网络编程（4）——使用post方式提交数据和文件

本节内容

1.常规方式post普通数据

2.底层方式post普通数据

3.文件上传

一、常规方式post普通数据

1.首先创建一个URL对象

URL url= new URL("http://127.0.0.1/login.php");

2.获取链接对象

        HttpURLConnection coon=(HttpURLConnection) url.openConnection();
        coon.setRequestMethod("POST");
        coon.setDoOutput(true);
        coon.setConnectTimeout(5*1000);

3.拼接上传的普通数据

String params ="user_name=jack&user_password=123";

4.获取输出流对象，注意：使用DataOutputStream包裹字节输出流，DataOutputStream是一个平台无关类

OutputStream os= coon.getOutputStream();
 DataOutputStream out=new DataOutputStream(os);

5.将自己的数据写出到输出流中

 out.writeBytes(params);
        out.flush();
        out.close();

6.获取服务器的响应信息

InputStream is =coon.getInputStream();
       DataInputStream in =new DataInputStream(is);
       byte []buffer =new byte[1024];
       int len= in.read(buffer);
      String content= new String(buffer,0,len);
      System.out.println(content);

二、底层方式POST普通数据(按照html上传的数据格式来上传)

//post底层方式提交普通数据
    public static void postData2()throws Exception{
        URL url= new URL("http://127.0.0.1/login.php");
        HttpURLConnection coon =(HttpURLConnection)url.openConnection();
        //设置请求方式为post
        coon.setRequestMethod("POST");
        //打开输出流
        coon.setDoOutput(true);
        //设置请求头部信息
        coon.setRequestProperty("Content-type","multipart/form-data, boundary==AaB03x");
        //发送请求体数据
        OutputStream os = coon.getOutputStream();
        DataOutputStream out = new DataOutputStream(os);

        out.writeBytes("--AaB03x\r\n");
        out.writeBytes("content-disposition: form-data; name=\"user_name\"\r\n");
        out.writeBytes("\r\n");
        out.writeBytes("jack\r\n");
        out.writeBytes("--AaB03x\r\n");
        out.writeBytes("content-disposition: form-data; name=\"user_password\"\r\n");
        out.writeBytes("\r\n");
        out.writeBytes("123\r\n");
        out.writeBytes("--AaB03x--\r\n");
        out.flush();
        out.close();
        //获取服务器的响应信息
        InputStream is =coon.getInputStream();
        DataInputStream in =new DataInputStream(is);
        byte []buffer =new byte[1024];
        int len= in.read(buffer);
        String content= new String(buffer,0,len);
        System.out.println(content);

    }

三、文件上传

public static void postFile() throws Exception{
        URL url= new URL("http://127.0.0.1/upload.php");
        HttpURLConnection coon =(HttpURLConnection)url.openConnection();
        coon.setRequestMethod("POST");
        coon.setDoOutput(true);
        coon.setRequestProperty("Content-type","multipart/form-data, boundary==AaB03x");
        OutputStream os = coon.getOutputStream();
        DataOutputStream out= new DataOutputStream(os);
        out.writeBytes("--AaB03x\r\n");
        out.writeBytes("content-disposition: form-data; name=\"file\";filename=\"abc.jpg\"\r\n");
        out.writeBytes("Content-Type: image/jpg\r\n\r\n");

        //图片的具体内容
        //创建文件的输入流对象
        FileInputStream fis = new FileInputStream("C:\\Users\\86178\\Pictures\\Saved Pictures\\1.jpg");
        BufferedInputStream bis=new BufferedInputStream(fis);
        byte [] buffer =new byte[1024];
        int  len =0;
        while((len=bis.read(buffer))!=-1){
            out.write(buffer,0,len);
        }
        out.writeBytes("\r\n");
        out.writeBytes("--AaB03x--\r\n");
        out.flush();
        out.close();
        bis.close();
        //获取服务器的响应信息
        InputStream is =coon.getInputStream();
        DataInputStream in =new DataInputStream(is);
        len= in.read(buffer);
        String content= new String(buffer,0,len);
        System.out.println(content);

    }