1 獲取html請求報文

使用POST上傳檔案
前端標籤樣例

<form action="http://www.baidu.com/" method="post" enctype="multipart/form-data">
    <input type="text" name="myText" /><br />
    <input type="file" name="upload1" /><br />
    <
 
input type="file" name="upload2" /><br />
    <input type="submit" />
</form>

為了實驗所需，我們建立兩個檔案file1.txt和file2.txt，內容分別為“This is file1.”及“This is file2, it’s bigger.”。在文字框裡寫上“hello world”，並選擇這兩個檔案，提交，則會看到瀏覽器傳遞了如下資料：

POST http://www.baidu.com/ HTTP/1.1
Host: www.
 
baidu.com
Content-Length: 495
Content-Type: multipart/form-data; boundary=---------------------------7db2d1bcc50e6e

-----------------------------7db2d1bcc50e6e
Content-Disposition: form-data; name="myText"

hello world
-----------------------------7db2d1bcc50e6e
Content-Disposition: form-data;
 
 name="upload1"; filename="C:\file1.txt"
Content-Type: text/plain

This is file1.
-----------------------------7db2d1bcc50e6e
Content-Disposition: form-data; name="upload2"; filename="C:\file2.txt"
Content-Type: text/plain

This is file2, it's longer.
-----------------------------7db2d1bcc50e6e--

2 通過Java URL讀取本地圖片傳送給服務端

程式碼如下

public void sendFiles(String path,String requestPath){
    String boundary = "--test";
    String format = "\r\n";
    String formatTwo = "\r\n\r\n";
    try {
        URL url = new URL(requestPath);

        HttpURLConnection conn = (HttpURLConnection)url.openConnection();

        conn.setDoInput(true);
        conn.setDoOutput(true);
        conn.setConnectTimeout(5000);
        conn.setReadTimeout(4000);
        conn.setRequestProperty("Connection","Keep-Alive");
        conn.setRequestProperty("Charset","UTF-8");
        conn.setRequestProperty("Content-Type","multipart/form-data; boundary="+boundary);
        conn.connect();

        OutputStream out = new DataOutputStream(conn.getOutputStream());
        out.write(formatTwo.getBytes(StandardCharsets.UTF_8));
        InputStream in =null;
        File file = new File(path);

        for(File file1 : file.listFiles()){

            if(file1.isDirectory()){continue;}

            out.write(("--"+boundary+format).getBytes(StandardCharsets.UTF_8));
            String contentType = "Content-Disposition: form-data; name=\"files\"; filename="+"\""+file1.getName()+"\"";
            out.write((contentType+format).getBytes(StandardCharsets.UTF_8));
            contentType = "Content-Type: text/plain";
            out.write((contentType+formatTwo).getBytes(StandardCharsets.UTF_8));

            in = new FileInputStream(file1);
            byte[] by = new byte[1024];
            int temp = -1;
            while ((temp=in.read(by))!=-1){
                out.write(by);
            }
            out.write(format.getBytes(StandardCharsets.UTF_8));
        }
        out.write(("--"+boundary).getBytes(StandardCharsets.UTF_8));
        in.close();
        out.flush();
        out.close();
        BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String line = null;
        while ((line = reader.readLine()) != null) {
            System.out.println("---line---"+line);
        }
    }catch (Exception e){
        e.printStackTrace();
    }
}

注意多個檔案用分割字串分割時在前一定要加- -

3 服務端接收檔案

程式碼如下

@ResponseBody
@RequestMapping("/upload/files")
public String uploadFiles(@RequestParam("files") MultipartFile[] files){

    for (MultipartFile multipartFile : files){

        String fileName = multipartFile.getOriginalFilename();

        try {
            File file = new File(filePath + File.separator + fileName);

            multipartFile.transferTo(file);
        }catch (Exception e){
            e.printStackTrace();

        }
    }
    return "成功";
   }