HttpUrlConnection Post请求

package com.example.administrator.myapplication.activity;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.webkit.WebView;
import android.widget.Button;
import android.widget.Toast;

import com.example.administrator.myapplication.R;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.charset.Charset;

public class HttpUrlConnectionPostActivity extends AppCompatActivity {
    WebView webView;
    Button postBtn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_http_url_connection_post);
        webView = (WebView) findViewById(R.id.webView);
        postBtn = (Button) findViewById(R.id.post);
        postBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        HttpUrlConnectionPost();
                    }
                }).start();
            }
        });

    }

    private void HttpUrlConnectionPost(){
        try {
            URL url = new URL("https://www.baidu.com/");
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setConnectTimeout(5*1000);
            connection.setReadTimeout(5*1000);
            //设置是否向httpURLConnection写入内容
            //post请求必须设置为true,因为post请求参数是否写在http正文中
            connection.setDoOutput(true);
            //设置是否从HttpURLConnection读入内容，默认为true
            connection.setDoInput(true);
            //设置是否使用缓存，post请求不使用缓存
            connection.setUseCaches(false);
            //设置请求方法  注意大小写!
            connection.setRequestMethod("POST");
            //设置长连接
            //connection.setRequestProperty("Connection","keep-Alive");
            //设置字符集
            connection.setRequestProperty("Charset","utf-8");
            //connection.setRequestProperty("Content-type","application/x-www-");

            //!!!重点部分，设置参数
            String params = "page = 1 & num = 10";
            OutputStream os = connection.getOutputStream();
            os.write(params.getBytes());
            os.flush();
            os.close();
            if (connection.getResponseCode() == HttpURLConnection.HTTP_OK){
                InputStream is = connection.getInputStream();
                StringBuilder sb = new StringBuilder();
                byte[] bytes = new byte[1024];
                int i = 0;
                while ((i = is.read(bytes)) != -1){
                    sb.append(new String(bytes,0,i,"utf-8"));
                }
                is.close();

                Message message = handler.obtainMessage(1,sb.toString());
                handler.sendMessage(message);
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            if (msg != null && msg.what == 1){
                String s = (String) msg.obj;
                String data = new String(s.getBytes(), Charset.forName("utf-8"));
                webView.getSettings().setDefaultTextEncodingName("utf-8");
                webView.getSettings().setJavaScriptEnabled(true);
                webView.loadDataWithBaseURL(null,data,"text/html","utf-8",null);
                Toast.makeText(getApplication(),"post请求成功!",Toast.LENGTH_SHORT).show();
            }
        }
    };
}

 <WebView
        android:id="@+id/webView"
        android:layout_width="match_parent"
        android:layout_height="400dp"></WebView>

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