Android HTTP请求

直接上代码：

代码中有GET和POST两种方法：

package com.example.camera.demohttp;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.Looper;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.Toast;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private HandlerThread handlerThread;
    private Handler handler;
    private ImageView imageView;

    private final int DOWNDLOAD = 1;
    private final int REGISTER = 2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViewById(R.id.downloadFile).setOnClickListener(this);
        findViewById(R.id.register).setOnClickListener(this);
        imageView = findViewById(R.id.img);

        handlerThread = new HandlerThread("http");
        handlerThread.start();
        handler = new HttpHandler(handlerThread.getLooper());//让handler消息运行子线程
    }



    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.downloadFile:
                handler.sendEmptyMessage(DOWNDLOAD);
                break;
            case R.id.register:
                handler.sendEmptyMessage(REGISTER);
                break;
                default:
                    break;
        }
    }



    private class HttpHandler extends Handler {
        public HttpHandler(Looper looper) {
            super(looper);
        }
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case DOWNDLOAD:
                    downloadFile();
                    break;
                case REGISTER:
                    registerUser();
                    break;
                    default:
                        break;
            }
        }
    }

    //post请求
    private void registerUser() {

        String registerUrl = "http://169.254.230.253:8080/register";
        try {
            URL url = new URL(registerUrl);
            HttpURLConnection postConnection = (HttpURLConnection) url.openConnection();
            postConnection.setRequestMethod("POST");//post 请求
            postConnection.setConnectTimeout(1000*5);
            postConnection.setReadTimeout(1000*5);
            postConnection.setDoInput(true);//允许从服务端读取数据
            postConnection.setDoOutput(true);//允许写入
            postConnection.setRequestProperty("Content-type", "application/x-www-form-urlencoded");//以表单形式传递参数
            String postParms = "name=1702C2019&password=12345&verifyCode=8888";
            OutputStream outputStream = postConnection.getOutputStream();
            outputStream.write(postParms.getBytes());//把参数发送过去.
            outputStream.flush();
            final StringBuffer buffer = new StringBuffer();
            int code = postConnection.getResponseCode();
            if (code == 200) {//成功
                InputStream inputStream = postConnection.getInputStream();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                String line = null;//一行一行的读取
                while ((line = bufferedReader.readLine()) != null) {
                    buffer.append(line);//把一行数据拼接到buffer里
                }
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        //把从服务端获取的数据提示出来
                        Toast.makeText(MainActivity.this, buffer.toString(), Toast.LENGTH_SHORT).show();
                    }
                });
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //需要放到子线程中去,使用handlerThread.
    private void downloadFile() {
        String downloadUrl = "http://pic41.nipic.com/20140508/18609517_112216473140_2.jpg";
        String savePath = "/sdcard/flowergirl.jpg";

        File file = new File(savePath);
        if (file.exists()) {
            file.delete();//如果文件存在，先删掉
        }
        BufferedInputStream bufferedInputStream = null;
        FileOutputStream outputStream = null;
        try {
            URL url = new URL(downloadUrl);
            try {
                HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                httpURLConnection.setRequestMethod("GET");
                httpURLConnection.setConnectTimeout(1000*5);
                httpURLConnection.setReadTimeout(1000*5);
                httpURLConnection.setDoInput(true);
                httpURLConnection.connect();

                //代表请求成功
                if (httpURLConnection.getResponseCode() == 200) {
                    InputStream in = httpURLConnection.getInputStream();
                    bufferedInputStream = new BufferedInputStream(in);//文件输入流
                    outputStream = new FileOutputStream(savePath);
                    byte[] buffer = new byte[1024];
                    int length = 0;
                    while ((length = bufferedInputStream.read(buffer)) != -1) {
                        outputStream.write(buffer, 0, length);//写入文件
                    }
                    outputStream.flush();//强制把数据写入磁盘
                    final Bitmap bitmap = BitmapFactory.decodeFile(savePath);
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            imageView.setImageBitmap(bitmap);
                        }
                    });
                }

            } catch (IOException e) {
                e.printStackTrace();
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bufferedInputStream!= null) {
                    bufferedInputStream.close();
                }
                if (outputStream != null) {
                    outputStream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }


}