Android 初识网络之get/post方法演示

た入场券 2022-07-19 11:58 82阅读 0赞

**布局：**

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context="com.example.administrator.jreduch08.HttpActivity">   
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="查询（get方式）"
            android:id="@+id/search""/>
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="查询（post方式）"
            android:id="@+id/search1"
            android:layout_below="@+id/search"/>
    
        <TextView
            android:layout_width="match_parent"
            android:layout_height="100dp"
            android:text="查询结果"
            android:id="@+id/show"
            android:layout_below="@+id/search1"/>   
    </RelativeLayout>

**布局效果展示：**

**![Center][]**

**代码：**

package com.example.administrator.jreduch08;
    
    import android.os.AsyncTask;
    import android.os.Bundle;
    import android.support.v7.app.AppCompatActivity;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.TextView;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStream;
    import java.net.HttpURLConnection;
    import java.net.MalformedURLException;
    import java.net.URL;
    
    public class HttpActivity extends AppCompatActivity {
        private Button search;
        private TextView show;
        private Button search1;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_http);
            search= (Button) findViewById(R.id.search);
            search1= (Button) findViewById(R.id.search1);
            show= (TextView) findViewById(R.id.show);
            //get请求监听
            search.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    String url="http://192.168.42.23:8080/" +
                            "HttpTest/index.jsp?option=getUser&uName=jerehedu";
                    new MyGet().execute(url);
                }
            });
            //post请求监听
            search1.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    String[] arg=new String[2];
                    arg[0]="http://192.168.42.23:8080/" +
                            "HttpTest/index.jsp?option=getUser&uName=jerehedu";
                    arg[1]="option=getUser&uName=jerehedu";
                new MyPost().execute(arg);
                }
            });
        }
        public class MyPost extends AsyncTask<String,Void,String>{
    
            @Override
            protected String doInBackground(String... params) {
                StringBuilder sbd=new StringBuilder();
                HttpURLConnection con=null;
                InputStream is=null;
                try {
                    URL url=new URL(params[0]);
                    con= (HttpURLConnection) url.openConnection();
                    con.setConnectTimeout(5 * 1000);
                    con.setReadTimeout(5 * 1000);
                    con.setRequestMethod("POST");
                    con.setDoInput(true);
                    con.setDoInput(true);
                    con.setUseCaches(false);
                    con.setRequestProperty("Charset", "UTF-8");
                    con.setRequestProperty("Content-type", "application/x-www-form-urlencoded");
                    //strings应该是这样的样式 option=getUser&uName=jerehedu
                    String strings=params[1];
                    OutputStream os=con.getOutputStream();
                    os.write(strings.getBytes());
                    os.flush();
                    os.close();
                    if(con.getResponseCode()==200){
                     is= con.getInputStream();
                      int next=0;
                        byte b[]=new byte[1024];
                        while((next=is.read(b))>0){
                            sbd.append(new String(b,0,next));
                        }
                    }
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } finally {
                    if(is!=null){
                        try {
                            is.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    if(con!=null){
                        con.disconnect();
                    }
                }
                return sbd.toString();
            }
    
            @Override
            protected void onPostExecute(String s) {
                super.onPostExecute(s);
                show.setText("POST请求结果"+s);
            }
        }
        /*
         AsyncTask异步任务类
         异步任务类的第一个参数
         会传到doInBackground方法中。
         第三个参数
         指定doInBackground的返回值。
          doInBackground的返回值会被OnPostExecute方法接收
        */
        public class MyGet extends AsyncTask<String,Void,String>{
    
           //在onPreExecute在主线程中执行命令，通常用于进度条的初始化
            @Override
            protected void onPreExecute() {
                super.onPreExecute();
            }
            // doInBackground 在子线程中执行命令
            @Override
            protected String doInBackground(String... params) {
                HttpURLConnection con=null;
                InputStream is=null;
                StringBuilder sbd=new StringBuilder();
                try {
                    URL url=new URL(params[0]);
                    con= (HttpURLConnection) url.openConnection();
                    con.setConnectTimeout(5 * 1000);
                    con.setReadTimeout(5 * 1000);
                    /*
                    Http响应码
                    200：成功
                    404：未找到
                    500：发生错误
                     */
                    if(con.getResponseCode()==200){
                        is=con.getInputStream();
                        int next=0;
                        byte[] bt=new byte[1024];
                        while((next=is.read(bt))>0){
                            sbd.append(new String(bt,0,next));
                        }
                    }
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }finally {
                    if(is!=null){
                        try {
                            is.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                   if(con!=null){
                       con.disconnect();
                   }
                }
                return sbd.toString();
            }
            //OnPostExecute 在UI线程中执行命令。
            @Override
            protected void onPostExecute(String s) {
                super.onPostExecute(s);
                show.setText(s);
            }
        }
    }效果展示：

![Center 1][]

[Center]: /images/20220718/849d9d0078a24aeabd66db8100847dfc.png
[Center 1]: /images/20220718/f730582697624c2895630662b185a40d.png