Android4.0 对网络Jason对象的解析（二） 客户端

      1.要在客户端实现对Json对象的解析，首先我们在清单文件加好权限：可以上网的权限，注意，在此之时，也一定要看看设备有没有联网，就是说，要上网权限，手机也要同时联网。

         

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

       2.建立一个工具类去实现并处理一些东西，如：Http去获取InputStream，将InputStream转换成对应的JsonString，然后在将其封装成一个javaBean类传给Activitiy前台显示

package com.example.json_demo;

import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import org.json.JSONException;
import org.json.JSONObject;

import com.example.domain.Person;

public class HttpUtils {

	public HttpUtils() {
		// TODO Auto-generated constructor stub
	}

	public static String GetJsonString(String urlstr) {
        //通过Http协议去得到对应InputStream
		String Jsonstring = "";
		try {
			URL url = new URL(urlstr);
			HttpURLConnection conn = (HttpURLConnection) url.openConnection();
			conn.setConnectTimeout(3000);
			conn.setRequestMethod("GET");
			conn.setDoInput(true);
			InputStream input = conn.getInputStream();
			int code = conn.getResponseCode();
			System.out.println("-->>response code" + code);
			//如果说这个连接成功，就将input变成一个JsonString，
			//一般来说对应的JsonString是 {‘Key’：‘Value’}
			if (code == 200) {
				Jsonstring = changeInputStreamToString(input);
				System.out.println("--》JsonString" + Jsonstring);
				
			}

		} catch (MalformedURLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return Jsonstring;
	}

	private static String changeInputStreamToString(InputStream input) {
		// 通过 byteArrayoutputStream 写入byte然后转换成string类型
		String jsonstr = "";
		ByteArrayOutputStream byteout = new ByteArrayOutputStream();
		byte[] by = new byte[4 * 1024];
		int len = 0;
		try {
			while (len != -1) {
				byteout.write(by, 0, len);
				len = input.read(by);
			}
			jsonstr = new String(byteout.toByteArray());

		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}
		return jsonstr;
	}

	// 通过JsonStrng得到对应Json 的对象
	public static Person getPersonObject(String key, String JsonStr) {

		Person person = new Person();
		try {
			// 将怎么个大的String变成一个 JSON 对象
			JSONObject jsonObject = new JSONObject(JsonStr);
			// 取其中的key后面的变成value 后的 Json对象
			JSONObject personPobject = jsonObject.getJSONObject(key);
			//将 Json中的对象的值，转换成JavaBean的对象的属性值
			person.setId(personPobject.getInt("id"));
			person.setAge(personPobject.getInt("age"));
			person.setName(personPobject.getString("name"));

		} catch (JSONException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

		return person;
	}
}
Person 类：

package com.example.domain;
public class Person {
	private int id;
	private String name;
	private String address;
	private int age;

	public Person(int id, String name, String address, int age) {
		super();
		this.id = id;
		this.name = name;
		this.address = address;
		this.age = age;
	}

	public Person() {
		// TODO Auto-generated constructor stub
	}

	@Override
	public String toString() {
		return "Person [id=" + id + ", name=" + name + ", address=" + address
				+ ", age=" + age + "]";
	}

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

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

	public String getAddress() {
		return address;
	}

	public void setAddress(String address) {
		this.address = address;
	}

	public int getAge() {
		return age;
	}

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

主要的Activity

package com.example.json_demo;

import com.example.domain.Person;

import android.location.GpsStatus.Listener;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends ActionBarActivity {
	private Runnable run;

	private Button button1, button2, button3, button4;

	private String str = "";

	private OnClickListener listener = new OnClickListener() {

		@Override
		public void onClick(View v) {
			// 新的线程去实现对应的方法
			
			switch (v.getId()) {
			case R.id.Button:
				run = new Runnable() {
					// 通过子线程去获取到Jsson
					public void run() {
						String path = "http://192.168.1.4:8080/BackWen/servlet/JsonAction?action_flag=person";
						str = HttpUtils.GetJsonString(path);
						Person person = HttpUtils.getPersonObject("person", str);
						System.out.println("--> Person" + person.getAge());
					}
				};
				Thread mythread = new Thread(run);
				mythread.start();
				System.out.println(str);
				break;
			case R.id.Button1:

				break;
			case R.id.Button2:

				break;
			case R.id.Button3:

				break;
			}

		}
	};

	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		//初始化各个组件
		button1 = (Button) findViewById(R.id.Button);
		button2 = (Button) findViewById(R.id.Button1);
		button3 = (Button) findViewById(R.id.Button2);
		button4 = (Button) findViewById(R.id.Button3);
        //添加监听
		button1.setOnClickListener(listener);
		button2.setOnClickListener(listener);
		button3.setOnClickListener(listener);
		button4.setOnClickListener(listener);

	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		// Handle action bar item clicks here. The action bar will
		// automatically handle clicks on the Home/Up button, so long
		// as you specify a parent activity in AndroidManifest.xml.
		int id = item.getItemId();
		if (id == R.id.action_settings) {
			return true;
		}
		return super.onOptionsItemSelected(item);
	}
}

 最后就是对应得布局，很简单

<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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.json_demo.MainActivity" >

    <Button
        android:id="@+id/Button"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="解析Json object" />