文件上传

最新推荐文章于 2024-10-02 11:29:37 发布

原创最新推荐文章于 2024-10-02 11:29:37 发布 · 281 阅读

CC 4.0 BY-SA版权

本文介绍了一个使用Java Servlet实现的文件上传服务。通过Apache Commons FileUpload库解析HTTP请求中的多部分表单数据，实现文件的接收与保存。文章详细展示了如何配置文件上传组件，并通过示例代码说明了文件上传的具体步骤。

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package cn.et.servlet04;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
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;

public class UploadServlet extends HttpServlet {

/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

this.doPost(request, response);
}
static String SAVE_DIR="E:/UploadServlet";
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
// 接收文件
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
// 判断是否是文件上传
if(isMultipart){
// 用于创建解析文件上传的工厂类
DiskFileItemFactory factory = new DiskFileItemFactory();
// 默认上传文件暂时存放在临时目录 System.getProperty("java.io.tmpdir");
// 也有可能是tomcat中/temp目录
// 用于从请求中解析文件
ServletFileUpload upload = new ServletFileUpload(factory);
// 在解析之前设置字符集,解决文件名中文乱码问题
upload.setHeaderEncoding("UTF-8");
try {
// 解析出文件个数
List<FileItem> items = upload.parseRequest(request);
// 解析到底是文本输入还是文件
for(FileItem fi:items){
// fi.isFormField()=true表示输入的是文本框 false是文件
if(fi.isFormField()){
System.out.println(fi.getFieldName()+"**"+fi.getString());
}else{
// 获取文件名
String fileName=fi.getName();
// 获取文件的流(输出流)
InputStream is=fi.getInputStream();
// 文件存储路径
String destPath=SAVE_DIR+"/"+fileName;
// 获取文件写入路径的流，(输出流)写到存储默认路径：SAVE_DIR
FileOutputStream fis=new FileOutputStream(destPath);
// 定义一个缓冲流
byte[] bt=new byte[1024];
// 读取文件
int readN=-1;
while((readN=is.read(bt))!=-1){
fis.write(bt, 0, readN);
}
fis.close();
is.close();
}
}
out.print("上传成功");
System.out.println(items.size());
} catch (FileUploadException e) {
e.printStackTrace();
}

}
out.flush();
out.close();

}

}