HttpURLConnection的GET和POST请求方式

//使用GET简单获取数据

public class MainActivity extends AppCompatActivity {

    ImageView image;

    File file;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        image = (ImageView) findViewById(R.id.image);

        new Thread(){

            @Override

            public void run() {

                try {

                    //创建url对象

                    URL url = new URL("http://172.17.29.120/localuser/chenhao/img1.png");                    

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

                    //设置请求 方式 连接超时 读取超时

                    urlConnection.setRequestMethod("GET");

                    urlConnection.setConnectTimeout(10000);

                    urlConnection.setReadTimeout(10000);

                    //得到返回码

                    int code = urlConnection.getResponseCode();

                    if ( code== 200) {

                        //获取流

                        InputStream is = urlConnection.getInputStream();

                        //文件方式

                        file= new File(Environment.getExternalStorageDirectory().getPath(), "copy.jpg");

                        FileOutputStream fos = new FileOutputStream(file);

                        int len = 0;

                        byte[] b = new byte[1024];

                        while ((len = is.read(b)) != -1) {

                            fos.write(b, 0, len);

                        }

············//这里用的 decodeFile方法 可以直接用decodeStrean直接传一个 inputStream 就可以了

                        fos.close();

                        is.close();

                        final Bitmap bitmap = BitmapFactory.decodeFile(file.getPath());

                        //主线程 更改UI

                        runOnUiThread(new Runnable() {

                            @Override

                            public void run() {

                                image.setImageBitmap(bitmap);

                            }

                        });

                    }

                } catch (Exception e) {

                    e.printStackTrace();

                }

            }

        }.start();

    }
}

//使用Post简单提交数据

package com.example.administrator.myapplication;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.EditText;

import android.widget.TextView;

import android.widget.Toast;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.net.HttpURLConnection;

import java.net.MalformedURLException;

import java.net.URL;

import java.net.URLConnection;

public class MainActivity extends AppCompatActivity {

    private String path="http://123.206.70.44:8080/JavaWebTest/Upload_html?";

    private EditText etName;

    private EditText etPwd;

    private TextView tv;

    private String s;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        etName = (EditText) findViewById(R.id.etName);

        etPwd = (EditText) findViewById(R.id.etPwd);

        tv = (TextView) findViewById(R.id.tv);

    }

        public void butLog(View v){

            final String name = getTextString(etName);

            final String pwd = getTextString(etPwd);

            if(name==null){

                Toast.makeText(MainActivity.this,"账号不能为空",Toast.LENGTH_SHORT).show();

                return;

            }

            if(pwd==null){

                Toast.makeText(MainActivity.this,"密码不能为空",Toast.LENGTH_SHORT).show();

                return;

            }

            new Thread(){

                @Override

                public void run() {

                    try {

                        URL url=new URL(path);

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

                        connection.setRequestMethod("POST");

                        connection.setReadTimeout(5000);

                        connection.setConnectTimeout(5000);

                        //要向服务器写对的数据

                        String data="user="+name+"&password="+pwd;

                        //设置请求配置   Arg1:配置类型  Arg2:参数新值   String类型

                        connection.setRequestProperty("Content-Type","application/x-www-form-urlencoded");

                        connection.setRequestProperty("Content-Length",data.length()+"");

                        //设置是否要给服务器写数据

                        connection.setDoInput(true);

                        connection.setDoOutput(true);

                        //写数据

                        connection.getOutputStream().write(data.getBytes());

                        //从服务器读

                        int code = connection.getResponseCode();

                        if(code==200){

                            InputStream is = connection.getInputStream();

                            ByteArrayOutputStream baos=new ByteArrayOutputStream();

                            int len=0;

                            byte[] b=new byte[1024];

                            while((len=is.read(b))!=-1){

                                baos.write(b,0,len);

                                s =  baos.toString();

                            }

                            baos.close();

                            is.close();

                            System.out.println(s);

                            runOnUiThread(new Runnable() {

                                @Override

                                public void run() {

                                    tv.setText(s);

                                }

                            });

                        }

                    } catch (MalformedURLException e) {

                        e.printStackTrace();

                    } catch (IOException e) {

                        e.printStackTrace();

                    }

                }

            }.start();

        }

    public String getTextString(EditText editText){

        String s = editText.getText().toString();

        if(s!=null && !s.equals("")){

            return  s;

        }

        return  null;

    }

}