java post 文件--图片

post 上传图片

写在前面的：

代码中标黄的地方“Content-Type: image/jpeg” ，服务器端得到文件才会是“xxx.jpeg”;

网上大多数代码都是“Content-Type: application/octet-stream” ，这时服务器端得到的文件是“xxx.octet-stream”

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
 
 
 
 
public class PostFileTest {
     
 
    public static void main(String[] args) {
         
        String filePath = "E:\\2.jpg";
        String urlS = "http://localhost:8070/SpringMVCTest/hellofile/uploadfile";
         
         
        try{
            String boundary = "Boundary-b1ed-4060-99b9-fca7ff59c113"; //Could be any string
            String Enter = "\r\n";
             
            File file = new File(filePath);
            FileInputStream fis = new FileInputStream(file);
             
            URL url = new URL(urlS);
            HttpURLConnection conn = (HttpURLConnection)url.openConnection();
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setRequestMethod("POST");
            conn.setUseCaches(false);
            conn.setInstanceFollowRedirects(true);
            conn.setRequestProperty("Content-Type","multipart/form-data;boundary=" + boundary); 
             
            conn.connect();
             
            DataOutputStream dos = new DataOutputStream(conn.getOutputStream());
           
          //part 1
            String part1 =  "--" + boundary + Enter
                    + "Content-Type: image/jpeg" + Enter
                    + "Content-Disposition: form-data; filename=\""+file.getName()+"\"; name=\"file\"" + Enter + Enter;
          //part 2
            String part2 = Enter
                    + "--" + boundary + Enter
                    + "Content-Type: text/plain" + Enter
                    + "Content-Disposition: form-data; name=\"dataFormat\"" + Enter + Enter
                    + "hk" + Enter
                    + "--" + boundary + "--";
            System.out.println("part1: "+part1);
            System.out.println("part2: "+part2);
             
            byte[] fileBytes = new byte[fis.available()];
            fis.read(fileBytes);
             
            dos.writeBytes(part1);
            dos.write(fileBytes);
            dos.writeBytes(part2);
             
            dos.flush();
            dos.close();
            fis.close();
             
            System.out.println("status code: "+conn.getResponseCode());
            // 得到响应流
            InputStream responseStream = conn.getInputStream();
            // 获取响应
            BufferedReader reader = new BufferedReader(new InputStreamReader(responseStream));
            String line;
            StringBuilder message = new StringBuilder();
            while ((line = reader.readLine()) != null) {
                message.append(line);
            }
            // 获取返回信息
            //return message.toString();
            System.out.println("return: "+message.toString());
             
         
            conn.disconnect();
             
        }catch(Exception e){
            e.printStackTrace();
        }
 
 
 
    }
 
}