我的 sql 中有一个图像，我想在网页中检索它，所以我开发了一个 servlet。现在，当我点击提交按钮时，它会调用 servlet，但不会显示图像，但如果我正在编写 localhost:8080/y/testimageServlet，则会在浏览器中显示图像。
imagetestServlet.java
import java.sql.*;
import DB.DataBaseConnection;
import java.io.IOException;
import java.io.InputStream;
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 imagetestServlet
*/
@WebServlet("/imagetestServlet")
public class imagetestServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public imagetestServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException,ServletException {
Blob image = null;
Connection con = null;
Statement stmt = null;
ResultSet rs = null;
DataBaseConnection db= new DataBaseConnection();
ServletOutputStream out = response.getOutputStream();
try {
Class.forName("com.mysql.jdbc.Driver");
con=db.connet();
stmt = con.createStatement();
rs = stmt.executeQuery("select img from one where id = '4'");
if (rs.next()) {
image = rs.getBlob(1);
} else {
response.setContentType("text/html");
out.println("<font color='red'>image not found for given id</font>");
return;
}
response.setContentType("image/gif");
InputStream in = image.getBinaryStream();
int length = (int) image.length();
int bufferSize = 1024;
byte[] buffer = new byte[bufferSize];
while ((length = in.read(buffer)) != -1) {
out.write(buffer, 0, length);
}
in.close();
out.flush();
} catch (Exception e) {
response.setContentType("text/html");
out.println("<html><head><title>Unable To Display image</title></head>");
out.println("<body><h4><font color='red'>Image Display Error=" + e.getMessage() +
"</font></h4></body></html>");
return;
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
}
登录
<form id="f1" name="f1" action="imagetest" method="post" onsubmit="return ccheck()">
<img src="header.png"><br><br><br><br><br>
<table >
<tr>
<td>
<table class="table">
<tr>
<td>
<table class="table">
<tr>
<td>
<div class="content"><div class="signin-header"><h3>Welcome to DiaEmr</h3></div></div>
</td>
</tr>
<tr>
<td>
<div class="content">
<div class="signin-box">
<p class="one">
Welcome to all at the <b>"Workshop on Ileal Interposition".</b><br>
<b>Brazil</b> to inaugurate & launch this very important Data Registry<br>
Key features of the solution-<br>
</div>
</div>
</td>
</tr>
</table>
</td>
<td>image</td>
<td>
<table class="table" >
<tr>
<td>
<div class="content">
<div class="signin-header">
<h3>Portal Login</h3>
</div>
</div>
</td>
</tr>
<tr>
<td>
<div class="content">
<div align="center" class="signin-box">
<table class="table">
<tr>
<td><b>User ID</b></td>
<td><input name="uid" type="text" /></td>
</tr>
<tr >
<td><b>Password</b></td>
<td><input name="cpass" type="password" /></td>
</tr>
<tr >
<td><input type="submit"
class="button button-submit" value="Submit" /></td>
<td><input type="reset" class="button button-submit"
value="Reset" /></td>
<tr>New User<a href ="UserRegistration.jsp">Register</a></tr><br>
</tr>
</table>
</div>
</div>
</td>
</tr>
</table>
</td>
</tr>
</table>
</td>
</tr>
</table>
<div class="footer-bar">
<img align="left" src="footer.png">
</div>
</form>