I have created a MySQL database with entries similar to nurse roster, Now i need to send this data to optaplanner deployed on my server. To which file do i need to send it in the optaplanner folder deployed on server to get the results displayed on my webpage.
I'm using Xstream to generate XML file.
Can any one please give me brief on how to make this functionality work and get me the desired results.
The whole dataset serialization from and to XML is part of optaplanner-examples: OptaPlanner itself doesn't provide or require any serialization format. That being said, optaplanner-examples includes the following serialization formats:
Every example: XStream XML format in data directories unsolved and solved. The format is defined by the XStream annotations (#XStreamAlias etc) on the domain classes. In some cases the XML format is too verbose, causing OutOfMemoryError, for example for the big MachineReassignment B datasets.
Most examples: Competition specific TXT format in data directories import and export. The format is defined by the competition (see docs). In the examples GUI, click on button Import to load them.
I suggested you to read the final chapter in optaplanner manual / documentation :
Chapter 15. Integration
If your data source is a database, you can annotate your domain POJO's with JPA annotations. I think it will be a waste if you still store the data from database to xml file then feed the xml file to optaplanner, it will be more wise to feed your POJO objects to optaplanner directly.
I don't know what your web application technology, but the general algorithm will be like this :
Get POJO object data from your database (you can use JPA etc.)
Construct the solution class object
Feed the solution object to optaplanner solver
Get the best solution from optaplanner solver and present it to your user in your user desire.
Take a look at CloudBalancingHelloWorld.java class to get the basic idea. Hope this can help you.
package com.jdbcxml;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import org.w3c.dom.Document;
class EmployeeDAO
{
private Connection conn = null;
static
{
try
{
Class.forName("com.mysql.jdbc.Driver");
}
catch (Exception e)
{
e.printStackTrace();
}
}
public EmployeeDAO()
{
String url = "jdbc:mysql://50.62.23.184:3306/gtuser";
String userId = "gtuser1";
String passWord = "";
try
{
conn = DriverManager.getConnection(url, userId, passWord);
}
catch (SQLException e)
{
e.printStackTrace();
}
}
public void finalize()
{
try
{
conn.close();
}
catch (SQLException e)
{
e.printStackTrace();
}
}
public Document getCustomerList()
{
Document doc = null;
try
{
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * from t7_users");
doc = JDBCUtil.toDocument(rs);
rs.close();
stmt.close();
}
catch (Exception e)
{
e.printStackTrace();
}
return doc;
}
public String getCustomerListAsString()
{
String xml = null;
try
{
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * from t7_users");
xml = JDBCUtil.toXML(rs);
rs.close();
stmt.close();
}
catch (Exception e)
{
e.printStackTrace();
}
return xml;
}
public static void main(String argv[]) throws Exception
{
EmployeeDAO dao = new EmployeeDAO();
String xml = dao.getCustomerListAsString();
System.out.println(xml);
Document doc = dao.getCustomerList();
System.out.println(doc);
//PrintWriter out = new PrintWriter(new FileWriter("output.txt"));
//out.write(doc);;
//out.close();
}
}
Here the pseudo code (I never actually use JSP, I currently using GWT) to give you the basic idea, but please do remember these notes :
I think it will be a waste to save your POJO objects to xml then use XStream library to extract it again to POJO objects. In optaplanner example, they use it because it only need a static data and for the sake of example.
I assume that you already create your approriate domain class model that fit your planning problem domain. Because this is one of the core concept of optaplanner.
In method generateCustomerRoster, you should put your own logic to convert your customer POJO objects to planning solution object.
Hope this can help you and lead you to finish your job. Thanks & Regards.
package com.jdbcxml;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import org.w3c.dom.Document;
public class EmployeeDAO
{
private Connection conn = null;
static
{
try
{
Class.forName("com.mysql.jdbc.Driver");
}
catch (Exception e)
{
e.printStackTrace();
}
}
public EmployeeDAO()
{
String url = "jdbc:mysql://50.62.23.184:3306/gtuser";
String userId = "gtuser1";
String passWord = "";
try
{
conn = DriverManager.getConnection(url, userId, passWord);
}
catch (SQLException e)
{
e.printStackTrace();
}
}
public void finalize()
{
try
{
conn.close();
}
catch (SQLException e)
{
e.printStackTrace();
}
}
public List<Customer> getCustomerList()
{
Document doc = null;
try
{
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * from t7_users");
doc = JDBCUtil.toDocument(rs);
rs.close();
stmt.close();
}
catch (Exception e)
{
e.printStackTrace();
}
return doc;
}
public CustomerRoster generateCustomerRoster(List<Customer> rawData) {
CustomerRoster result = new CustomerRoster();
// here you should write your logic to generate Customer Roster data from your Raw Data (Customer)
return result;
}
public static void main(String argv[]) throws Exception
{
// Build the Solver
SolverFactory solverFactory = SolverFactory.createFromXmlResource("yourSolverConfig.xml");
Solver solver = solverFactory.buildSolver();
// Load your problem
EmployeeDAO dao = new EmployeeDAO();
List<Customer> listCustomer = dao.getCustomerList();
CustomerRoster unsolvedCustomerRoster = generateCustomerRoster(listCustomer);
// Solve the problem
solver.solve(unsolvedCustomerRoster);
CustomerRoster solvedCustomerRoster = (CustomerRoster) solver.getBestSolution();
// Display the result
DataGrid grid = new DataGrid(solvedCustomerRoster); // Just change this line code to display to any of your view component
}
}
Related
My code is as follows.
import org.xbill.DNS.Lookup;
import org.xbill.DNS.Record;
import org.xbill.DNS.Type;
public class MailCheckService {
public Record[] mailHostValidate(String email, MailEntity mailEntity) {
Record[] records = null;
String hostName = email.split("#")[1];
try {
Lookup lookup = new Lookup(hostName, Type.MX);
lookup.run();
records = lookup.getAnswers();
} catch (IOException e) {
throw e;
}
return records;
}
}
how can i mock the Lookup class or rewrite it.
if possible, please provide the version of jar.
Thanks and best regards.
I am currently building an API gateway for a new microservices system, using the Spring Netflix Zuul library.
So far my gateway contains PRE and POST filters that intercept the requests and perform the required logic, etc.
One thing that I see is that REST calls to specific microservices require invoking an API endpoint (either GET or POST) containing JSON payload data that is very complex.
For an end-user sending a request to a microservice containing this JSON would not be user friendly.
I had an idea such that the API gateway act as a mediator, where the user can submit a more "simplified/ user-friendly" JSON to the API gateway, which will transform the JSON payload with the correct "complex" JSON structure that the target microservice can understand in order to handle the request efficiently.
My understanding of how Netflix Zuul is that this can be done by creating a RouteFilter and then including this logic here.
Can anyone explain if (or how) this transformation could be done using Netflix Zuul?
Any advice is appreciated.
Thanks.
No doubt you can do it with Zuul, i am currently trying to do almost the same. i'd suggest you take a look at this repo :
sample-zuul-filters
and the official doc on github.
Filters have to extend ZuulFilter and implement the following methods :
/**
*return a string defining when your filter must execute during zuul's
*lyfecyle ('pre'/'post' routing
**/
#Override
public String filterType(){
return 'pre'; // run this filter before sending the final request
}
/**
* return an int describing the order that the filter should run on,
* (relative to the other filters and the current 'pre' or 'post' context)
**/
#Override
public int filterOrder {
return 1; //this filter runs first in a pre-request context
}
/**
* return a boolean indicating if the filter should run or not
**/
#Override
public boolean shouldFilter() {
RequestContext ctx = RequestContext.getCurrentContext();
if(ctx.getRequest().getRequestURI().equals("/theRouteIWantToFilter"))
{
return true;
}
else {
return false;
}
}
/**
* After all the config stuffs you can set what your filter actually does
* here. This is where your json logic goes.
*/
#Override
public Object run() {
try {
RequestContext ctx = RequestContext.getCurrentContext();
HttpServletRequest request = ctx.getRequest();
InputStream stream = ctx.getResponseDataStream();
String body = StreamUtils.copyToString(stream, Charset.forName("UTF-8"));
// transform your json and send it to the api.
ctx.setResponseBody(" Modified body : " + body);
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
I am not sure my answer is 100% accurate since i am working on it but it's a start.
I've done payload conversion in pre filter but this should work in route filter as well. Use com.netflix.zuul.http.HttpServletRequestWrapper to capture and modify the original request payload before forwarding the request to target microservice.
Sample code:
package com.sample.zuul.filters.pre;
import com.google.common.io.CharStreams;
import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import com.netflix.zuul.http.HttpServletRequestWrapper;
import com.netflix.zuul.http.ServletInputStreamWrapper;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
public class JsonConverterFilter extends ZuulFilter {
#Override
public String filterType() {
return "pre";
}
#Override
public int filterOrder() {
return 0; // Set it to whatever the order of your filter is
}
#Override
public boolean shouldFilter() {
return true;
}
#Override
public Object run() {
RequestContext context = RequestContext.getCurrentContext();
HttpServletRequest request = new HttpServletRequestWrapper(context.getRequest());
String requestData = null;
JSONParser jsonParser = new JSONParser();
JSONObject requestJson = null;
try {
if (request.getContentLength() > 0) {
requestData = CharStreams.toString(request.getReader());
}
if (requestData == null) {
return null;
}
requestJson = (JSONObject) jsonParser.parse(requestData);
} catch (Exception e) {
//Add your exception handling code here
}
JSONObject modifiedRequest = modifyJSONRequest(requestJson);
final byte[] newRequestDataBytes = modifiedRequest.toJSONString().getBytes();
request = getUpdatedHttpServletRequest(request, newRequestDataBytes);
context.setRequest(request);
return null;
}
private JSONObject modifyJSONRequest(JSONObject requestJSON) {
JSONObject jsonObjectDecryptedPayload = null;
try {
jsonObjectDecryptedPayload = (JSONObject) new JSONParser()
.parse("Your new complex json");
} catch (ParseException e) {
e.printStackTrace();
}
return jsonObjectDecryptedPayload;
}
private HttpServletRequest getUpdatedHttpServletRequest(HttpServletRequest request, final byte[] newRequestDataBytes) {
request = new javax.servlet.http.HttpServletRequestWrapper(request) {
#Override
public BufferedReader getReader() throws IOException {
return new BufferedReader(
new InputStreamReader(new ByteArrayInputStream(newRequestDataBytes)));
}
#Override
public ServletInputStream getInputStream() throws IOException {
return new ServletInputStreamWrapper(newRequestDataBytes);
}
/*
* Forcing any calls to HttpServletRequest.getContentLength to return the accurate length of bytes
* from a modified request
*/
#Override
public int getContentLength() {
return newRequestDataBytes.length;
}
};
return request;
}
}
How can I retrieve and display images from a database in a JSP page?
Let's see in steps what should happen:
JSP is basically a view technology which is supposed to generate HTML output.
To display an image in HTML, you need the HTML <img> element.
To let it locate an image, you need to specify its src attribute.
The src attribute needs to point to a valid http:// URL and thus not a local disk file system path file:// as that would never work when the server and client run at physically different machines.
The image URL needs to have the image identifier in either the request path (e.g. http://example.com/context/images/foo.png) or as request parameter (e.g. http://example.com/context/images?id=1).
In JSP/Servlet world, you can let a Servlet listen on a certain URL pattern like /images/*, so that you can just execute some Java code on specific URL's.
Images are binary data and are to be obtained as either a byte[] or InputStream from the DB, the JDBC API offers the ResultSet#getBytes() and ResultSet#getBinaryStream() for this, and JPA API offers #Lob for this.
In the Servlet you can just write this byte[] or InputStream to the OutputStream of the response the usual Java IO way.
The client side needs to be instructed that the data should be handled as an image, thus at least the Content-Type response header needs to be set as well. You can obtain the right one via ServletContext#getMimeType() based on image file extension which you can extend and/or override via <mime-mapping> in web.xml.
That should be it. It almost writes code itself. Let's start with HTML (in JSP):
<img src="${pageContext.request.contextPath}/images/foo.png">
<img src="${pageContext.request.contextPath}/images/bar.png">
<img src="${pageContext.request.contextPath}/images/baz.png">
You can if necessary also dynamically set src with EL while iterating using JSTL:
<c:forEach items="${imagenames}" var="imagename">
<img src="${pageContext.request.contextPath}/images/${imagename}">
</c:forEach>
Then define/create a servlet which listens on GET requests on URL pattern of /images/*, the below example uses plain vanilla JDBC for the job:
#WebServlet("/images/*")
public class ImageServlet extends HttpServlet {
// content=blob, name=varchar(255) UNIQUE.
private static final String SQL_FIND = "SELECT content FROM Image WHERE name = ?";
#Resource(name="jdbc/yourDB") // For Tomcat, define as <Resource> in context.xml and declare as <resource-ref> in web.xml.
private DataSource dataSource;
#Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String imageName = request.getPathInfo().substring(1); // Returns "foo.png".
try (Connection connection = dataSource.getConnection(); PreparedStatement statement = connection.prepareStatement(SQL_FIND)) {
statement.setString(1, imageName);
try (ResultSet resultSet = statement.executeQuery()) {
if (resultSet.next()) {
byte[] content = resultSet.getBytes("content");
response.setContentType(getServletContext().getMimeType(imageName));
response.setContentLength(content.length);
response.getOutputStream().write(content);
} else {
response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404.
}
}
} catch (SQLException e) {
throw new ServletException("Something failed at SQL/DB level.", e);
}
}
}
That's it. In case you worry about HEAD and caching headers and properly responding on those requests, use this abstract template for static resource servlet.
See also:
How should I connect to JDBC database / datasource in a servlet based application?
How to upload an image and save it in database?
Simplest way to serve static data from outside the application server in a Java web application
I suggest you address that as two problems. There are several questions and answer related to both.
How to load blob from MySQL
See for instance Retrieve image stored as blob
How to display image dynamically
See for instance Show thumbnail dynamically
I've written and configured the code in JSP using Oracle database.
Hope it will help.
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.http.HttpSession;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class displayfetchimage
*/
#WebServlet("/displayfetchimage")
public class displayfetchimage extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* #see HttpServlet#HttpServlet()
*/
public displayfetchimage() {
super();
// TODO Auto-generated constructor stub
}
/**
* #see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
Statement stmt = null;
String sql = null;
BufferedInputStream bin = null;
BufferedOutputStream bout = null;
InputStream in = null;
response.setContentType("image/jpeg");
ServletOutputStream out;
out = response.getOutputStream();
Connection conn = employee.DbConnection.getDatabaseConnection();
HttpSession session = (HttpSession) request.getSession();
String ID = session.getAttribute("userId").toString().toLowerCase();
try {
stmt = conn.createStatement();
sql = "select user_image from employee_data WHERE username='" + ID + "' and rownum<=1";
ResultSet result = stmt.executeQuery(sql);
if (result.next()) {
in = result.getBinaryStream(1);// Since my data was in first column of table.
}
bin = new BufferedInputStream(in);
bout = new BufferedOutputStream(out);
int ch = 0;
while ((ch = bin.read()) != -1) {
bout.write(ch);
}
} catch (SQLException ex) {
Logger.getLogger(displayfetchimage.class.getName()).log(Level.SEVERE, null, ex);
} finally {
try {
if (bin != null)
bin.close();
if (in != null)
in.close();
if (bout != null)
bout.close();
if (out != null)
out.close();
if (conn != null)
conn.close();
} catch (IOException | SQLException ex) {
System.out.println("Error : " + ex.getMessage());
}
}
}
// response.getWriter().append("Served at: ").append(request.getContextPath());
/**
* #see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Statement stmt = null;
String sql = null;
BufferedInputStream bin = null;
BufferedOutputStream bout = null;
InputStream in = null;
response.setContentType("image/jpeg");
ServletOutputStream out;
out = response.getOutputStream();
Connection conn = employee.DbConnection.getDatabaseConnection();
HttpSession session = (HttpSession) request.getSession();
String ID = session.getAttribute("userId").toString().toLowerCase();
try {
stmt = conn.createStatement();
sql = "select user_image from employee_data WHERE username='" + ID + "' and rownum<=1";
ResultSet result = stmt.executeQuery(sql);
if (result.next()) {
in = result.getBinaryStream(1);
}
bin = new BufferedInputStream(in);
bout = new BufferedOutputStream(out);
int ch = 0;
while ((ch = bin.read()) != -1) {
bout.write(ch);
}
} catch (SQLException ex) {
Logger.getLogger(displayfetchimage.class.getName()).log(Level.SEVERE, null, ex);
} finally {
try {
if (bin != null)
bin.close();
if (in != null)
in.close();
if (bout != null)
bout.close();
if (out != null)
out.close();
if (conn != null)
conn.close();
} catch (IOException | SQLException ex) {
System.out.println("Error : " + ex.getMessage());
}
}
}
}
Try to flush and close the output stream if it does not display.
Blob image = rs.getBlob(ImageColName);
InputStream in = image.getBinaryStream();
// Output the blob to the HttpServletResponse
response.setContentType("image/jpeg");
BufferedOutputStream o = new BufferedOutputStream(response.getOutputStream());
byte by[] = new byte[32768];
int index = in.read(by, 0, 32768);
while (index != -1) {
o.write(by, 0, index);
index = in.read(by, 0, 32768);
}
o.flush();
o.close();
I used SQL SERVER database and so the answer's code is in accordance. All you have to do is include an <img> tag in your jsp page and call a servlet from its src attribute like this
<img width="200" height="180" src="DisplayImage?ID=1">
Here 1 is unique id of image in database and ID is a variable. We receive value of this variable in servlet. In servlet code we take the binary stream input from correct column in table. That is your image is stored in which column. In my code I used third column because my images are stored as binary data in third column. After retrieving input stream data from table we read its content in an output stream so it can be written on screen. Here is it
import java.io.*;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.*;
import javax.servlet.http.*;
import model.ConnectionManager;
public class DisplayImage extends HttpServlet {
public void doGet(HttpServletRequest request,HttpServletResponse response)
throws IOException
{
Statement stmt=null;
String sql=null;
BufferedInputStream bin=null;
BufferedOutputStream bout=null;
InputStream in =null;
response.setContentType("image/jpeg");
ServletOutputStream out;
out = response.getOutputStream();
Connection conn = ConnectionManager.getConnection();
int ID = Integer.parseInt(request.getParameter("ID"));
try {
stmt = conn.createStatement();
sql = "SELECT * FROM IMAGETABLE WHERE ID="+ID+"";
ResultSet result = stmt.executeQuery(sql);
if(result.next()){
in=result.getBinaryStream(3);//Since my data was in third column of table.
}
bin = new BufferedInputStream(in);
bout = new BufferedOutputStream(out);
int ch=0;
while((ch=bin.read())!=-1)
{
bout.write(ch);
}
} catch (SQLException ex) {
Logger.getLogger(DisplayImage.class.getName()).log(Level.SEVERE, null, ex);
}finally{
try{
if(bin!=null)bin.close();
if(in!=null)in.close();
if(bout!=null)bout.close();
if(out!=null)out.close();
if(conn!=null)conn.close();
}catch(IOException | SQLException ex){
System.out.println("Error : "+ex.getMessage());
}
}
}
}
After the execution of your jsp or html file you will see the image on screen.
You can also create custom tag for displaying image.
1) create custom tag java class and tld file.
2) write logic to display image like conversion of byte[] to string by Base64.
so it is used for every image whether you are displaying only one image or multiple images in single jsp page.
How can I retrieve and display images from a database in a JSP page?
Let's see in steps what should happen:
JSP is basically a view technology which is supposed to generate HTML output.
To display an image in HTML, you need the HTML <img> element.
To let it locate an image, you need to specify its src attribute.
The src attribute needs to point to a valid http:// URL and thus not a local disk file system path file:// as that would never work when the server and client run at physically different machines.
The image URL needs to have the image identifier in either the request path (e.g. http://example.com/context/images/foo.png) or as request parameter (e.g. http://example.com/context/images?id=1).
In JSP/Servlet world, you can let a Servlet listen on a certain URL pattern like /images/*, so that you can just execute some Java code on specific URL's.
Images are binary data and are to be obtained as either a byte[] or InputStream from the DB, the JDBC API offers the ResultSet#getBytes() and ResultSet#getBinaryStream() for this, and JPA API offers #Lob for this.
In the Servlet you can just write this byte[] or InputStream to the OutputStream of the response the usual Java IO way.
The client side needs to be instructed that the data should be handled as an image, thus at least the Content-Type response header needs to be set as well. You can obtain the right one via ServletContext#getMimeType() based on image file extension which you can extend and/or override via <mime-mapping> in web.xml.
That should be it. It almost writes code itself. Let's start with HTML (in JSP):
<img src="${pageContext.request.contextPath}/images/foo.png">
<img src="${pageContext.request.contextPath}/images/bar.png">
<img src="${pageContext.request.contextPath}/images/baz.png">
You can if necessary also dynamically set src with EL while iterating using JSTL:
<c:forEach items="${imagenames}" var="imagename">
<img src="${pageContext.request.contextPath}/images/${imagename}">
</c:forEach>
Then define/create a servlet which listens on GET requests on URL pattern of /images/*, the below example uses plain vanilla JDBC for the job:
#WebServlet("/images/*")
public class ImageServlet extends HttpServlet {
// content=blob, name=varchar(255) UNIQUE.
private static final String SQL_FIND = "SELECT content FROM Image WHERE name = ?";
#Resource(name="jdbc/yourDB") // For Tomcat, define as <Resource> in context.xml and declare as <resource-ref> in web.xml.
private DataSource dataSource;
#Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String imageName = request.getPathInfo().substring(1); // Returns "foo.png".
try (Connection connection = dataSource.getConnection(); PreparedStatement statement = connection.prepareStatement(SQL_FIND)) {
statement.setString(1, imageName);
try (ResultSet resultSet = statement.executeQuery()) {
if (resultSet.next()) {
byte[] content = resultSet.getBytes("content");
response.setContentType(getServletContext().getMimeType(imageName));
response.setContentLength(content.length);
response.getOutputStream().write(content);
} else {
response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404.
}
}
} catch (SQLException e) {
throw new ServletException("Something failed at SQL/DB level.", e);
}
}
}
That's it. In case you worry about HEAD and caching headers and properly responding on those requests, use this abstract template for static resource servlet.
See also:
How should I connect to JDBC database / datasource in a servlet based application?
How to upload an image and save it in database?
Simplest way to serve static data from outside the application server in a Java web application
I suggest you address that as two problems. There are several questions and answer related to both.
How to load blob from MySQL
See for instance Retrieve image stored as blob
How to display image dynamically
See for instance Show thumbnail dynamically
I've written and configured the code in JSP using Oracle database.
Hope it will help.
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.http.HttpSession;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class displayfetchimage
*/
#WebServlet("/displayfetchimage")
public class displayfetchimage extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* #see HttpServlet#HttpServlet()
*/
public displayfetchimage() {
super();
// TODO Auto-generated constructor stub
}
/**
* #see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
Statement stmt = null;
String sql = null;
BufferedInputStream bin = null;
BufferedOutputStream bout = null;
InputStream in = null;
response.setContentType("image/jpeg");
ServletOutputStream out;
out = response.getOutputStream();
Connection conn = employee.DbConnection.getDatabaseConnection();
HttpSession session = (HttpSession) request.getSession();
String ID = session.getAttribute("userId").toString().toLowerCase();
try {
stmt = conn.createStatement();
sql = "select user_image from employee_data WHERE username='" + ID + "' and rownum<=1";
ResultSet result = stmt.executeQuery(sql);
if (result.next()) {
in = result.getBinaryStream(1);// Since my data was in first column of table.
}
bin = new BufferedInputStream(in);
bout = new BufferedOutputStream(out);
int ch = 0;
while ((ch = bin.read()) != -1) {
bout.write(ch);
}
} catch (SQLException ex) {
Logger.getLogger(displayfetchimage.class.getName()).log(Level.SEVERE, null, ex);
} finally {
try {
if (bin != null)
bin.close();
if (in != null)
in.close();
if (bout != null)
bout.close();
if (out != null)
out.close();
if (conn != null)
conn.close();
} catch (IOException | SQLException ex) {
System.out.println("Error : " + ex.getMessage());
}
}
}
// response.getWriter().append("Served at: ").append(request.getContextPath());
/**
* #see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Statement stmt = null;
String sql = null;
BufferedInputStream bin = null;
BufferedOutputStream bout = null;
InputStream in = null;
response.setContentType("image/jpeg");
ServletOutputStream out;
out = response.getOutputStream();
Connection conn = employee.DbConnection.getDatabaseConnection();
HttpSession session = (HttpSession) request.getSession();
String ID = session.getAttribute("userId").toString().toLowerCase();
try {
stmt = conn.createStatement();
sql = "select user_image from employee_data WHERE username='" + ID + "' and rownum<=1";
ResultSet result = stmt.executeQuery(sql);
if (result.next()) {
in = result.getBinaryStream(1);
}
bin = new BufferedInputStream(in);
bout = new BufferedOutputStream(out);
int ch = 0;
while ((ch = bin.read()) != -1) {
bout.write(ch);
}
} catch (SQLException ex) {
Logger.getLogger(displayfetchimage.class.getName()).log(Level.SEVERE, null, ex);
} finally {
try {
if (bin != null)
bin.close();
if (in != null)
in.close();
if (bout != null)
bout.close();
if (out != null)
out.close();
if (conn != null)
conn.close();
} catch (IOException | SQLException ex) {
System.out.println("Error : " + ex.getMessage());
}
}
}
}
Try to flush and close the output stream if it does not display.
Blob image = rs.getBlob(ImageColName);
InputStream in = image.getBinaryStream();
// Output the blob to the HttpServletResponse
response.setContentType("image/jpeg");
BufferedOutputStream o = new BufferedOutputStream(response.getOutputStream());
byte by[] = new byte[32768];
int index = in.read(by, 0, 32768);
while (index != -1) {
o.write(by, 0, index);
index = in.read(by, 0, 32768);
}
o.flush();
o.close();
I used SQL SERVER database and so the answer's code is in accordance. All you have to do is include an <img> tag in your jsp page and call a servlet from its src attribute like this
<img width="200" height="180" src="DisplayImage?ID=1">
Here 1 is unique id of image in database and ID is a variable. We receive value of this variable in servlet. In servlet code we take the binary stream input from correct column in table. That is your image is stored in which column. In my code I used third column because my images are stored as binary data in third column. After retrieving input stream data from table we read its content in an output stream so it can be written on screen. Here is it
import java.io.*;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.*;
import javax.servlet.http.*;
import model.ConnectionManager;
public class DisplayImage extends HttpServlet {
public void doGet(HttpServletRequest request,HttpServletResponse response)
throws IOException
{
Statement stmt=null;
String sql=null;
BufferedInputStream bin=null;
BufferedOutputStream bout=null;
InputStream in =null;
response.setContentType("image/jpeg");
ServletOutputStream out;
out = response.getOutputStream();
Connection conn = ConnectionManager.getConnection();
int ID = Integer.parseInt(request.getParameter("ID"));
try {
stmt = conn.createStatement();
sql = "SELECT * FROM IMAGETABLE WHERE ID="+ID+"";
ResultSet result = stmt.executeQuery(sql);
if(result.next()){
in=result.getBinaryStream(3);//Since my data was in third column of table.
}
bin = new BufferedInputStream(in);
bout = new BufferedOutputStream(out);
int ch=0;
while((ch=bin.read())!=-1)
{
bout.write(ch);
}
} catch (SQLException ex) {
Logger.getLogger(DisplayImage.class.getName()).log(Level.SEVERE, null, ex);
}finally{
try{
if(bin!=null)bin.close();
if(in!=null)in.close();
if(bout!=null)bout.close();
if(out!=null)out.close();
if(conn!=null)conn.close();
}catch(IOException | SQLException ex){
System.out.println("Error : "+ex.getMessage());
}
}
}
}
After the execution of your jsp or html file you will see the image on screen.
You can also create custom tag for displaying image.
1) create custom tag java class and tld file.
2) write logic to display image like conversion of byte[] to string by Base64.
so it is used for every image whether you are displaying only one image or multiple images in single jsp page.
I got struck while trying to do the coding part. Following is the part which i tried. I'm in need to know the #Test portion. I don't know to write the Selenium code to part to fetch the data from excel and to insert the data in MySQL.
import org.testng.annotations.BeforeTest;
import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;
import com.thoughtworks.selenium.SeleneseTestBase;
import java.io.File;
import java.sql.*;
import jxl.*;
public class testng extends SeleneseTestBase{
#BeforeTest
public static void connection()
{
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
#BeforeTest
public static void MysqlConnection() //we need to add the Dataprovider name[name="DP"] to pass the data from excel sheet
{
try {
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root", "admin");
Statement stmt = conn.createStatement();
} catch (SQLException e) {
e.printStackTrace();
return;
}
System.out.println("Testing Testfile1");
}
#DataProvider(name = "DP1")
public Object[][] createData1() throws Exception{
Object[][] retObjArr=getTableArray("D:\\sakthi\\selenium\\data3.xls","DataPool", "mysqldata");
return(retObjArr);
}
#Test (dataProvider = "DP1")
public void testDataProviderExample(int id, int plist_id, String email) throws Exception {
//This is the part where i'm in need of help
}
public String[][] getTableArray(String xlFilePath, String sheetName, String tableName) throws Exception{
String[][] tabArray=null;
Workbook workbook = Workbook.getWorkbook(new File(xlFilePath));
Sheet sheet = workbook.getSheet(sheetName);
int startRow,startCol, endRow, endCol,ci,cj;
Cell tableStart=sheet.findCell(tableName);
startRow=tableStart.getRow();
startCol=tableStart.getColumn();
Cell tableEnd= sheet.findCell(tableName, startCol+1,startRow+1, 100, 64000, false);
endRow=tableEnd.getRow();
endCol=tableEnd.getColumn();
System.out.println("startRow="+startRow+", endRow="+endRow+", " +"startCol="+startCol+", endCol="+endCol);
tabArray=new String[endRow-startRow-1][endCol-startCol-1];
ci=0;
for (int i=startRow+1;i<endRow;i++,ci++){
cj=0;
for (int j=startCol+1;j<endCol;j++,cj++){
tabArray[ci][cj]=sheet.getCell(j,i).getContents();
}
}
return(tabArray);
}
}
Selenium is used to control a web browser, you don't need it open an excel file and write to a DB.