Json入门

参考《疯狂android讲义》》730页

JSON的基础请参考W3SCHOOL的教程：
http://www.w3school.com.cn/json/index.asp
例子：
http://wenku.baidu.com/link?url=A5SiKBUNVx-aB_hFiDuHsEN1uw_Vu4a9ODRq7G-SpiY-qW11Ve8Ba8ym9TfheAUuHJhYgdD3g05lvGNWrPBzf7JZFhUlAcZYb0MMIdrcmp3
1、创建服务器端：

（1）创建对象类

package com.ljh.jsondemo.model;

public class User {

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 getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
private int id;
private String name;
private String email;
private String gender;
}

（2）创建json的提供类

package com.ljh.jsondemo.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.json.JSONArray;
import org.json.JSONObject;

import com.ljh.jsondemo.model.User;

public class JsonDemoServlet extends HttpServlet {

private static final long serialVersionUID = -7368225680407826408L;

private List<User> list;

/** * 处理post方式提交的数据 */

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {
doGet(request, response);

}

/** * 处理get方式提交的数据 */

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/plain");

response.setCharacterEncoding("UTF-8");

PrintWriter out = response.getWriter();

// 准备用户数据

prepareData();

// JSON数组

JSONArray array = new JSONArray();

for (User bean : list) {

// 单个用户JSON对象

JSONObject obj = new JSONObject();

try {
obj.put("id", bean.getId());

obj.put("name", bean.getName());

obj.put("email", bean.getEmail());

obj.put("gender", bean.getGender());

}

catch (Exception e) {
}

array.put(obj);

}

// 输出

out.write(array.toString());

out.flush();
out.close();
}

private void prepareData() {

list = new ArrayList<User>();

User bean1 = new User();

bean1.setId(1001);

bean1.setName("Tony");

bean1.setEmail("");

bean1.setGender("male");

list.add(bean1);

User bean2 = new User();

bean2.setId(1002);

bean2.setName("Jack");

bean2.setEmail("");

bean2.setGender("male");

list.add(bean2);

User bean3 = new User();

bean3.setId(1003);

bean3.setName("Marry");

bean3.setEmail("");

bean3.setGender("female");

list.add(bean3);

User bean4 = new User();

bean4.setId(1004);

bean4.setName("Linda");

bean4.setEmail("");

bean4.setGender("female");

list.add(bean4);

}

}

2、创建android客户端

注意要添加访问internet的权限。

package com.ljh.jsondemoclient;

import java.io.BufferedReader;
import java.io.InputStreamReader;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.json.JSONArray;
import org.json.JSONObject;

import android.os.Bundle;
import android.app.Activity;
import android.widget.TextView;

public class MainActivity extends Activity {

private String getContent(String url) throws Exception {

StringBuilder sb = new StringBuilder();

HttpClient client = new DefaultHttpClient();

HttpParams httpParams = client.getParams();

// 设置网络超时参数

HttpConnectionParams.setConnectionTimeout(httpParams, 3000);

HttpConnectionParams.setSoTimeout(httpParams, 5000);

HttpResponse response = client.execute(new HttpGet(url));

HttpEntity entity = response.getEntity();

if (entity != null) {
System.out.println("test!!!!");

BufferedReader reader = new BufferedReader(new InputStreamReader(
entity.getContent(), "UTF-8"), 8192);

String line = null;

while ((line = reader.readLine()) != null) {

sb.append(line + "\n");

}

reader.close();

}
return sb.toString();

}

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

try {

StringBuffer sb = new StringBuffer();

// 在测试过程中，经常是用本机做测试服务器，访问本机的IP地址要设置为10.0.2.2

String url = "192.168.136.133:8080/JsonDemoServer/JsonDemoServlet";

String body = getContent(url);

JSONArray array = new JSONArray(body);

for (int i = 0; i < array.length(); i++) {

JSONObject obj = array.getJSONObject(i);

sb.append("id:").append(obj.getInt("id")).append("\t");

sb.append("name:").append(obj.getString("name")).append("\r\n");

sb.append("gender:").append(obj.getString("gender"))
.append("\t");

sb.append("email:").append(obj.getString("email"))
.append("\r\n");

sb.append("----------------------\r\n");

}

TextView textView = (TextView) findViewById(R.id.tv_json_content);

textView.setText(sb.toString());

} catch (Exception e) {
}
}
}