AsyncTask POST请求

布局：

 <?xml version="1.0" encoding="utf-8"?>
 <android.support.constraint.ConstraintLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     tools:context="net.bwie.network.activity.PostActivity">

     <Button
         android:id="@+id/post_btn"
         android:text="post请求"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"/>

 </android.support.constraint.ConstraintLayout>

Activity:

 /**
  * 当前案例：
  * 上传姓名和年龄，返回JSON字符串
  */
 public class PostActivity extends AppCompatActivity implements View.OnClickListener {

     protected Button mPostBtn;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         super.setContentView(R.layout.activity_post);
         initView();
     }

     @Override
     public void onClick(View view) {
         if (view.getId() == R.id.post_btn) {
             doPost();
         }
     }

     // 使用异步任务执行POST请求
     private void doPost() {
         String url = "http://localhost:8080/postdemo";

         PostTask task = new PostTask();
         task.execute(url);
     }

     private void initView() {
         mPostBtn = (Button) findViewById(R.id.post_btn);
         mPostBtn.setOnClickListener(PostActivity.this);
     }

     private class PostTask extends AsyncTask<String, Void, Person> {

         @Override
         protected Person doInBackground(String... params) {
             String requestUrl = params[0];

             URL url = null;
             try {
                 url = new URL(requestUrl);
                 HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                 // 设置POST请求
                 connection.setRequestMethod("POST");
                 // 设置可向服务器输出
                 connection.setDoOutput(true);
                 // 打开连接
                 connection.connect();

                 // 打开连接后，向服务端写要提交的参数
                 // 参数格式：“name=asdasdas&age=123123”
                 StringBuilder stringBuilder = new StringBuilder();
                 stringBuilder.append("name=")
                         .append("wuyanzu")// 拼接自己传入的姓名
                         .append("&")
                         .append("age=")
                         .append("123");// 拼接自己传入的年龄
                 // 获取向服务器写数据的输出流
                 connection.getOutputStream()
                         .write(stringBuilder.toString().getBytes());

                 // 提交数据后，获取来自服务器的json数据
                 if (connection.getResponseCode() == 200) {
                     BufferedReader br = null;
                     br = new BufferedReader(new InputStreamReader(connection.getInputStream()));

                     String json = "";
                     String line = "";

                     while ((line = br.readLine()) != null) {
                         json += line.trim();
                     }

                     // 解析
                     Gson gson = new Gson();
                     Person person = gson.fromJson(json, Person.class);
                     return person;

                 }

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

             return null;
         }

         @Override
         protected void onPostExecute(Person person) {
             super.onPostExecute(person);

             Log.d("1507", "name:" + person.getName() + ", age: " + person.getAge());
         }
     }

 }

Bean:

 package net.bwie.network.bean;

 public class Person {

     private String name = "";
     private String age = "";

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public String getAge() {
         return age;
     }

     public void setAge(String age) {
         this.age = age;
     }
 }

权限：  <uses-permission android:name="android.permission.INTERNET"/>