代碼：
index.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><!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=UTF-8"><title>檔案上傳</title></head><body> <form action="FileUploadServlet" method="post" enctype="multipart/form-data"> 選擇上傳檔案： <input type="file" name="file" id="file" accept="image/*"/><br/><br/> <input type="submit" value="上傳" name="upload" id="upload"/> </form></body></html>
package com.servlet;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.io.PrintWriter;import java.sql.Connection;import java.sql.SQLException;import java.sql.PreparedStatement;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.annotation.MultipartConfig;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.Part;import com.connect.DButil;@MultipartConfig//標識Servlet支援檔案上傳public class FileUploadServlet extends HttpServlet {private static final long serialVersionUID = 1L; public FileUploadServlet() { super(); // TODO Auto-generated constructor stub } protected void processRequest(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{ response.setContentType("text/html;charset=UTF-8"); request.setCharacterEncoding("UTF-8"); final Part filePart=request.getPart("file"); final String fileName=getFileName(filePart); Connection conn=null; OutputStream out=null; InputStream filecontent=null; final PrintWriter writer=response.getWriter(); try { conn=DButil.open();conn.setAutoCommit(false);String sql="INSERT INTO images(name,image) VALUES(?,?)";PreparedStatement stmt=(PreparedStatement) conn.prepareStatement(sql);stmt.setString(1, fileName);filecontent=filePart.getInputStream();stmt.setBinaryStream(2, filecontent, (int)filePart.getSize());stmt.execute();conn.commit();response.sendRedirect("disping.jsp");} catch (SQLException e) {// TODO Auto-generated catch blockwriter.println("<br/>錯誤："+e.getMessage());e.printStackTrace();} finally {if(conn!=null){try {conn.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}if(out!=null){out.close();}if(filecontent!=null){filecontent.close();}if(writer!=null){writer.close();}} }private String getFileName(final Part part) {// TODO Auto-generated method stubfor(String content : part.getHeader("content-disposition").split(";")){String filename=content.substring(content.lastIndexOf('\\')+1).trim().replace("\"", "");return filename;}return null;}protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubprocessRequest(request, response);}protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubprocessRequest(request, response);}}
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><!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=UTF-8"><title>顯示最後一張圖片</title></head><body> <h4>顯示最後一張圖片</h4> <img alt="圖片" src="ImageServlet"/></body></html>
package com.servlet;import java.io.IOException;import java.io.InputStream;import java.sql.ResultSet;import java.sql.SQLException;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;import com.connect.DButil;import com.mysql.jdbc.Connection;import com.mysql.jdbc.PreparedStatement;public class ImageServlet extends HttpServlet {private static final long serialVersionUID = 1L; public ImageServlet() { super(); // TODO Auto-generated constructor stub }protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubresponse.setContentType("image/jpeg");request.setCharacterEncoding("UTF-8");ServletOutputStream os=response.getOutputStream();Connection conn=null;try {conn=DButil.open();String sql="SELECT name,image FROM images ORDER BY id DESC";PreparedStatement stmt=(PreparedStatement) conn.prepareStatement(sql);ResultSet rs=stmt.executeQuery();if(rs.next()){//沒有用到@SuppressWarnings("unused") String name=rs.getString(1); byte[] buffer=new byte[1]; InputStream is=rs.getBinaryStream(2); while(is.read(buffer)>0){ os.write(buffer); } os.flush();}} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}finally {if(conn!=null){try {conn.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}if(os!=null){os.close();}}}}
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