Android4.0 对网络Jason对象的解析（二） 客户端
程序员文章站
2022-05-30 14:38:04
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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" />