Servlet 上传图片
预备
需求包
commons-fileupload -用于上传
jstl -用于jsp页面遍历
servlet-api -使用servlet
pom
<dependencies>
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
</dependencies>
前端代码
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>上传Demo</title>
</head>
<body>
<form action="uploadServlet" method="post"
enctype="multipart/form-data">
上传文件：<input type="file" name="file"><br/>
上传文件：<input type="file" name="file2"><br/>
<input type="submit" />
</form>
<c:forEach items="${pics }" var="p">
<img src="heads/${p }" />
</c:forEach>
</body>
</html>
后端处理代码
package com;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
@WebServlet("/uploadServlet")
public class uploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public uploadServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.sendRedirect("index.jsp");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 是否是多功能表单
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
if (!isMultipart) {
return;
}
// 目标服务端目录
String path = request.getSession().getServletContext().getRealPath("/heads");
// String path="D:/heads";
File file = new File(path);
// 如果目录不存在就创建目录
if (!file.exists() && !file.isDirectory()) {
file.mkdirs();
}
// 接受文件列表
List piclist = new ArrayList(); // 放上传的图片名
DiskFileItemFactory factory = new DiskFileItemFactory();
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setHeaderEncoding("UTF-8"); // 处理中文问题
upload.setSizeMax(1024 * 1024 * 5); // 限制文件大小5M
try {
// 得到所有表单元素
List<FileItem> fileItems = upload.parseRequest(request); // 解码请求
for (FileItem item : fileItems) {
System.out.println(item);
// 有可能是 文件，也可能是普通文字
if (item.isFormField()) { // 这个选项是 文字
System.out.println("表单值为：" + item.getString());
} else {
// 是文件
String fileName = item.getName();
System.out.println("文件名是:" + fileName); // 文件名
item.write(new File(path, fileName));
if (fileName.endsWith(".jpg") || fileName.endsWith(".png") || fileName.endsWith(".bmp") || fileName.endsWith(".ico") || fileName.endsWith(".gif")) {
piclist.add(fileName); // 把图片放入集合
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
// 去显示上传的文件
request.setAttribute("pics", piclist);
request.getRequestDispatcher("index.jsp").forward(request, response);
}
}