[英]Retrieve Image from Database and display in another jsp page
我正在嘗試從數據庫中檢索多個圖像,並將這些圖像顯示在另一個JSP頁面中。 首先,我嘗試將單個圖像顯示在特定的JSP頁面中,我檢索了該顯示,但顯示是以文件類型顯示的,我想在特定的JSP頁面中顯示該圖像。 我正在使用MySQL數據庫。
我的servlet代碼:
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/Retrieve")
public class Retrieve extends HttpServlet {
static {
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{ Connection con = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/vikas", "root", "root");
ps = con.prepareStatement("select * from rough");
rs=ps.executeQuery();
if (rs.next()) {
byte[] content = rs.getBytes("image");
response.setContentLength(content.length);
response.getOutputStream().write(content);
request.setAttribute("image", content);
RequestDispatcher rd=request.getRequestDispatcher("View.jsp");
rd.forward(request, response);
} else {
response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404.
}
} catch (SQLException e) {
throw new ServletException("Something failed at SQL/DB level.", e);
}
}
}
jsp代碼:
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Display Image</title>
</head>
<body>
<div>THE DISPLAY</div>
<div style="width:25%; height:25%">
<%request.getAttribute("image"); %>
</div>
</body>
</html>
嘗試使用Base64
編碼,
使用Apache Commons Codec進行Base64編碼。
byte[] content = rs.getBytes("image");
String base64Encoded = new String(Base64.encodeBase64(content), "UTF-8");
request.setAttribute("imageBt", base64Encoded);
從JSP檢索它
<img src="data:image/png;base64,${requestScope['imageBt']}"/>
對於多張圖片,您可以嘗試這樣的操作((我沒有嘗試過)
List<String> images = new ArrayList<>();
if (rs.next()) {
byte[] content = rs.getBytes("image");
images.add(new String(Base64.encodeBase64(content), "UTF-8"));
}
request.setAttribute("imageBt", images);
在JSP中
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<c:forEach var="img" items="${imageBt}">
<img src="data:image/png;base64, ${img}"/>
</c:forEach>
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