最简单的文件上传

1、在做之前需要导入的jar包组件：

commons-fileupload-1.2.1.jar、commons-io-2.0.jar（依赖包）

2、页面代码html>

<%@ 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>Insert title here</title>
</head>
<body>
	<form action="simpleFileupload" method="post" enctype="multipart/form-data">
	最简单的文件上传：<input type="file" name="fileupload"/>
	描述：<input type="text" name="desc"/>
	<input type="submit" value="submit"/>
	</form>
</body>
</html>

注意：这里的enctype(编码类型)是“multipart/form-data”

3、servlet代码

package com.xiaojie.simpleFileupload;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
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.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
/**
* Servlet implementation class SimpleFileupload
*/
@WebServlet("/simpleFileupload")
public class SimpleFileupload extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
//1、创建一个DiskFileItemFactory工厂
DiskFileItemFactory factory = new DiskFileItemFactory();
//2、创建一个文件上传解析器
ServletFileUpload upload = new ServletFileUpload(factory);
//解决上传文件名的中文乱码
upload.setHeaderEncoding("UTF-8");
factory.setSizeThreshold(1024 * 500);//设置内存的临界值为500K
File linshi = new File("E:\\linshi");//当超过500K的时候，存到一个临时文件夹中
factory.setRepository(linshi);
upload.setSizeMax(1024 * 1024 * 5);//设置上传的文件总的大小不能超过5M
try {
// 1. 得到 FileItem 的集合 items
List<FileItem> /* FileItem */items = upload.parseRequest(request);
// 2. 遍历 items:
for (FileItem item : items) {
// 若是一个一般的表单域, 打印信息
if (item.isFormField()) {
String name = item.getFieldName();
String value = item.getString("utf-8");
System.out.println(name + ": " + value);
}
// 若是文件域则把文件保存到 e:\\files 目录下.
else {
String fileName = item.getName();
long sizeInBytes = item.getSize();
System.out.println(fileName);
System.out.println(sizeInBytes);
InputStream in = item.getInputStream();
byte[] buffer = new byte[1024];
int len = 0;
fileName = "e:\\files\\" + fileName;//文件最终上传的位置
System.out.println(fileName);
OutputStream out = new FileOutputStream(fileName);
while ((len = in.read(buffer)) != -1) {
out.write(buffer, 0, len);
}
out.close();
in.close();
}
}
} catch (FileUploadException e) {
e.printStackTrace();
}
}
}

最简单的文件上传

1、在做之前需要导入的jar包组件：

2、页面代码html>

3、servlet代码

推荐阅读