android解析json数据

本文讲解android解析json数据。客户端接收服务端发来的4种json数据，分别解析成四种类型Person , List<Person> , List<String> , List<Map<String,Object>>，从MainActivity传递到OtherActivity.

接收的服务器端的4种json数据分别为：

1. {"person":{"address":"香港","id":1001,"name":"刘德华"}}  

2. {"persons":[{"address":"香港","id":1001,"name":"刘德华"},{"address":"韩国","id":1001,"name":"宋慧乔"}]}  

3. {"listString":["美国","中国","俄罗斯"]}  

4. {"listMap":[{"id":1001,"address":"香港","name":"刘德华"},{"id":1002,"address":"韩国","name":"宋慧乔"}]}  

客户端相应4种操作 ：

1. MainActivity 将json数据解析成Person类，用Intent将Peson对象传递给OtherActvity. 设置标记click_flag = person

2. MainActivity 将json数据解析成List<Person>，用Intent将List<Person>传递给OtherActvity. 设置标记click_flag = persons

3. MainActivity 将json数据解析成List<String>，用Intent将List<String>传递给OtherActvity. 设置标记click_flag = listString

4. MainActivity 将json数据解析成List<Map<String,Object>>，用Intent将List<Map<String,Object>>传递给OtherActvity. 设置标记click_flag = listMap

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三点重点注意点：

1. 在AndroidManifest.xml中 加上

    <!-- 添加访问网络的授权 -->
    <uses-permission android:name="android.permission.INTERNET" />

2. android中Http访问时 connection.getResponseCode()不被执行 。添加访问网络的授权后，仍不能执行

3. 在android的两个activity中，如何用Intent传递Person对象，List<Person>,List<Map<String,Object>>类型。

    一.Intent 传递 Person对象

           传递 intent.putExtra("person", (Serializable)person);

           接收 Person person =(Person) intent.getSerializableExtra("person");

    二.Intent 传递 List<Person>对象

           传递 intent.putExtra("persons", (Serializable) list);

           接收 List<Person> list = (List<Person>) intent.getSerializableExtra("persons");

    三. Intent传递 List<Map<String,Object>>类型

           传递 intent.putExtra("listMap", (Serializable) list);

           接收 List<Map<String, Object>> list = (List<Map<String, Object>>) intent.getSerializableExtra("listMap");

    注意：Intent 传递的对象object必须都实现Serializable接口，List<Object>内的object也必须要实现Serializable接口.

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1.点击“解析person数据”，反馈结果如下：

2. 点击“解析persons数据”，反馈结果如下：

3. 点击“解析listString数据”，反馈结果如下：

4.点击“解析listMap数据”，反馈结果如下：

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程序思路：

1.服务器端产生4种类型的json数据，客户端android用GET方式分别获取服务器端返回的json数据，http 请求传递参数action_flag. 服务器端根据action_flag 返回不同的json数据给客户端。

2.客户端将4种不同的json数据解析成4中不同的结果类型(Person,List<Person>,List<String>,List<Map<String,Object>>)，用Intent方式由MainActivity传递给OtherActivity,在OtherActvity中显示解析的结果。

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客户端android工程目录(左)和服务器端web工程目录(右)

      

1. AndroidManifest.xml 加上网络访问权限

    <!-- 添加访问网络的授权 -->
  <uses-permission android:name="android.permission.INTERNET" />

2.activity_main.xml 主机面

<LinearLayout 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:orientation="vertical">"<Buttonandroid:id="@+id/person"android:layout_width="match_parent"android:layout_height="wrap_content"android:text="解析Person数据" /><Buttonandroid:id="@+id/persons"android:layout_width="match_parent"android:layout_height="wrap_content"android:text="解析Persons数据" /><Buttonandroid:id="@+id/listString"android:layout_width="match_parent"android:layout_height="wrap_content"android:text="解析listString数据" /><Buttonandroid:id="@+id/listMap"android:layout_width="match_parent"android:layout_height="wrap_content"android:text="解析listMap数据" /></LinearLayout>

3. avtivity_other.xml 点击主界面的按钮后相应的界面

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical" ><TextView android:id="@+id/msg"android:layout_width="match_parent"android:layout_height="wrap_content"/></LinearLayout>

4.MainActivity.java

package com.android.myjson;import java.io.Serializable;import java.util.ArrayList;import java.util.List;import java.util.Map;import com.json.data.Person;import com.json.http.HttpUtils;import com.json.tools.JsonTools;import android.os.Bundle;import android.os.StrictMode;import android.annotation.SuppressLint;import android.app.Activity;import android.content.Intent;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class MainActivity extends Activity implements OnClickListener {private Button person, persons, listString, listMap;private static final String TAG = "MainActivity";@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);closeStrictMode();person = (Button) findViewById(R.id.person);persons = (Button) findViewById(R.id.persons);listString = (Button) findViewById(R.id.listString);listMap = (Button) findViewById(R.id.listMap);person.setOnClickListener(this);persons.setOnClickListener(this);listString.setOnClickListener(this);listMap.setOnClickListener(this);}@Overridepublic void onClick(View v) {String url_path = "";String jsonString = "";switch (v.getId()) {case R.id.person:url_path = "http://192.168.0.102:8080/json_Project/servlet/JsonAction?action_flag=person";jsonString = HttpUtils.getJsonContent(url_path, "utf-8");Person person = JsonTools.getPerson("person", jsonString);Intent intent = new Intent(MainActivity.this, OtherActivity.class);intent.putExtra("click_flag", "person"); // 标记当前intent是按钮 personintent.putExtra("person", (Serializable)person);startActivity(intent);break;case R.id.persons:url_path = "http://192.168.0.102:8080/json_Project/servlet/JsonAction?action_flag=persons";jsonString = HttpUtils.getJsonContent(url_path, "utf-8");try {List<Person> list = JsonTools.getPersons("persons", jsonString);Intent intent2 = new Intent(MainActivity.this,OtherActivity.class);intent2.putExtra("click_flag", "persons"); // 标记当前intent按钮是personsintent2.putExtra("persons", (Serializable) list);startActivity(intent2);} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}break;case R.id.listString:url_path = "http://192.168.0.102:8080/json_Project/servlet/JsonAction?action_flag=listString";jsonString = HttpUtils.getJsonContent(url_path, "utf-8");List<String> list = new ArrayList<String>();try {list = (ArrayList<String>) JsonTools.getListString("listString", jsonString);} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}Intent intent2 = new Intent(this, OtherActivity.class);intent2.putExtra("click_flag", "listString"); // 标记// 当前intent按钮是listStringintent2.putStringArrayListExtra("listString",(ArrayList<String>) list); // 参数中的list要加强制转换startActivity(intent2);break;case R.id.listMap:url_path = "http://192.168.0.102:8080/json_Project/servlet/JsonAction?action_flag=listMap";jsonString = HttpUtils.getJsonContent(url_path, "utf-8");List<Map<String, Object>> list2 = new ArrayList<Map<String, Object>>();try {list2 = JsonTools.getListMap("listMap", jsonString);} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}Intent intent3 = new Intent(MainActivity.this, OtherActivity.class);intent3.putExtra("click_flag", "listMap"); // 标记 当前intent按钮是listMap// 用Intent传递List<Map<String,Object>> 对象，其中HashMap实现了Serializableintent3.putExtra("listMap", (Serializable) list2);startActivity(intent3);break;}}@SuppressLint("NewApi")public static void closeStrictMode() {StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder().detectAll().penaltyLog().build());}}

5.OtherActivity.java

package com.android.myjson;import java.util.List;import java.util.Map;import com.json.data.Person;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.widget.TextView;public class OtherActivity extends Activity {private TextView textView;public OtherActivity() {// TODO Auto-generated constructor stub}@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.activity_other);textView = (TextView) findViewById(R.id.msg);Intent intent = getIntent();String click_flag = intent.getStringExtra("click_flag");if ("person".equals(click_flag)) { // 如果是点击 person按钮// 接收Intent传递的Person对象Person person =(Person) intent.getSerializableExtra("person");  textView.setText(person.toString());} else if ("persons".equals(click_flag)) {// 如果是点击 persons按钮// 接收Intent传递的List<Person>参数@SuppressWarnings("unchecked")List<Person> list = (List<Person>) intent.getSerializableExtra("persons");String persons = "";for (Person person : list) {persons += person.toString() + "\n";}textView.setText(persons);} else if ("listString".equals(click_flag)) {List<String> list = (List<String>) intent.getStringArrayListExtra("listString");String listString = "";for (String s : list) {listString += s + "\n";}textView.setText(listString);} else if ("listMap".equals(click_flag)) {//接收Intent传递的List<Map<String,Object>>参数@SuppressWarnings("unchecked")List<Map<String, Object>> list = (List<Map<String, Object>>) intent.getSerializableExtra("listMap");String listMapString = "";for (Map<String, Object> map : list) {// 遍历一个Mapfor (Map.Entry<String, Object> entry : map.entrySet()) {String key = entry.getKey();Object value = entry.getValue();listMapString += " " + key + " : " + value + " ";}listMapString += "\n";}textView.setText(listMapString);}}}

6.Person.java

package com.json.data;import java.io.Serializable;public class Person implements Serializable {/** *  */private static final long serialVersionUID = 1L;private int id;private String name;    private String address;public Person() {// TODO Auto-generated constructor stub}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 Person(int id, String name, String address) {super();this.id = id;this.name = name;this.address = address;}@Overridepublic String toString() {return "Person [id=" + id + ", name=" + name + ", address=" + address+ "]";}}

7.HttpUtils.java

package com.json.http;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.URL;import android.annotation.SuppressLint;import android.os.StrictMode;public class HttpUtils {public HttpUtils() {// TODO Auto-generated constructor stub}public static String getJsonContent(String url_path ,String encode){String jsonString = "";try {URL url = new URL(url_path);HttpURLConnection connection = (HttpURLConnection)url.openConnection();connection.setConnectTimeout(3000);connection.setRequestMethod("GET");connection.setDoInput(true);  //从服务器获得数据int responseCode = connection.getResponseCode();if (200 == responseCode) {jsonString = changeInputStream(connection.getInputStream(),encode);}} catch (Exception e) {// TODO: handle exception}//return jsonString;}private static String changeInputStream(InputStream inputStream , String encode) throws IOException {// TODO Auto-generated method stubString  jsonString = null;ByteArrayOutputStream outputStream = new ByteArrayOutputStream();byte[] data = new byte[1024];int len = 0;while((len=inputStream.read(data))!=-1){outputStream.write(data, 0, len);}jsonString = new String(outputStream.toByteArray(), encode);inputStream.close();return jsonString;}}

8.JsonTools.java

package com.json.tools;import java.util.ArrayList;import java.util.HashMap;import java.util.Iterator;import java.util.List;import java.util.Map;import org.json.JSONArray;import org.json.JSONException;import org.json.JSONObject;import com.json.data.Person;/** * 完成对json数据的解析 *  * @author ben *  */public class JsonTools {private static final String TAG = "JsonTools";public JsonTools() {// TODO Auto-generated constructor stub}public static Person getPerson(String key, String jsonString) {Person person = new Person();try {// jsonObject ={"person":{"address":"香港","id":1001,"name":"刘德华"}}JSONObject jsonObject = new JSONObject(jsonString);// personObject = {"address":"香港","id":1001,"name":"刘德华"}JSONObject personObject = jsonObject.getJSONObject(key); // 此处key = "person"person.setId(personObject.getInt("id"));person.setName(personObject.getString("name"));person.setAddress(personObject.getString("address"));} catch (Exception e) {// TODO: handle exception}return person;}public static List<Person> getPersons(String key , String jsonString) throws Exception{List<Person> list = new ArrayList<Person>();//jsonObject={"persons":[{"address":"香港","id":1001,"name":"刘德华"},{"address":"韩国","id":1002,"name":"宋慧乔"}]} JSONObject jsonObject = new JSONObject(jsonString);//jsonArray =[{"address":"香港","id":1001,"name":"刘德华"},{"address":"韩国","id":1002,"name":"宋慧乔"}]JSONArray jsonArray = jsonObject.getJSONArray(key);   //此处key = persons,取得for (int i = 0; i < jsonArray.length(); i++) {JSONObject personObject = jsonArray.getJSONObject(i);Person person = new Person();person.setId(personObject.getInt("id"));person.setName(personObject.getString("name"));  person.setAddress(personObject.getString("address"));list.add(person);}return list;}public static List<String> getListString(String key,String jsonString) throws Exception{List<String> list = new ArrayList<String>();// jsonObject = {"listString":["美国","中国","俄罗斯"]}JSONObject jsonObject = new JSONObject(jsonString);// jsonArray = ["美国","中国","俄罗斯"]JSONArray jsonArray = jsonObject.getJSONArray(key);for (int i =0 ; i<jsonArray.length();i++) {String s = jsonArray.getString(i);list.add(s);}return list;}public static List<Map<String, Object>> getListMap(String key , String jsonString) throws Exception{List<Map<String, Object>> list = new ArrayList<Map<String,Object>>();JSONObject jsonObject = new JSONObject(jsonString);JSONArray jsonArray = jsonObject.getJSONArray(key);for (int i = 0; i < jsonArray.length(); i++) {JSONObject jsonObject2 = jsonArray.getJSONObject(i);Map<String, Object> map = new HashMap<String, Object>();//重点：如何遍历json 对象中的keyIterator<String> iterator = jsonObject2.keys(); // 获取json对象中的key，返回一个string集合。while(iterator.hasNext()){String json_key = iterator.next();Object json_value = jsonObject2.get(json_key);if (json_value == null) { //因为JSON value可为 null;json_value = "";}map.put(json_key, json_value);}list.add(map);}return list;}    }

服务器端 json_Project

1.JsonAction.java

package com.json.action;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.json.service.JsonService;import com.json.tools.JsonTools;public class JsonAction extends HttpServlet {JsonService jsonService ;/** * Constructor of the object. */public JsonAction() {super();}/** * Destruction of the servlet. <br> */public void destroy() {super.destroy(); // Just puts "destroy" string in log// Put your code here}/** * The doGet method of the servlet. <br> * * This method is called when a form has its tag value method equals to get. *  * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {this.doPost(request, response);}/** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. *  * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("text/html;charset=utf-8");request.setCharacterEncoding("utf-8");response.setCharacterEncoding("utf-8");PrintWriter out = response.getWriter();// 获取 person的 list , 保存为json数据//String jsonString = JsonTools.creatJsonString("persons", jsonService.getListPersons());String jsonString ="";String action_flag = request.getParameter("action_flag");if ("person".equals(action_flag)) {jsonString = JsonTools.creatJsonString("person", jsonService.getPerson());} else if("persons".equals(action_flag)) {jsonString = JsonTools.creatJsonString("persons", jsonService.getListPersons());}else if("listString".equals(action_flag)) {jsonString = JsonTools.creatJsonString("listString", jsonService.getListString());}else if("listMap".equals(action_flag)) {jsonString = JsonTools.creatJsonString("listMap", jsonService.getListMap());}out.println(jsonString);System.out.println("jsonString"+jsonString);out.flush();out.close();}/** * Initialization of the servlet. <br> * * @throws ServletException if an error occurs */public void init() throws ServletException {// Put your code herejsonService = new JsonService();}}

2.Person.java

package com.json.data;public class Person {private int id;private String name;    private String address;public Person() {// TODO Auto-generated constructor stub}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 Person(int id, String name, String address) {super();this.id = id;this.name = name;this.address = address;}@Overridepublic String toString() {return "Person [id=" + id + ", name=" + name + ", address=" + address+ "]";}}

3.JsonService.java

package com.json.service;import java.util.ArrayList;import java.util.Map;import java.util.HashMap;import java.util.List;import com.json.data.Person;public class JsonService {public JsonService() {// TODO Auto-generated constructor stub}public static Person getPerson() {Person person = new Person(1001, "刘德华", "香港");return person;}public static List<Person> getListPersons() {List<Person> persons = new ArrayList<Person>();Person person1 = new Person(1001, "刘德华", "香港");Person person2 = new Person(1002, "宋慧乔", "韩国");persons.add(person1);persons.add(person2);return persons;}public static List<String> getListString(){List<String> list = new ArrayList<String>();list.add("美国");list.add("中国");list.add("俄罗斯");return list;} public static List<java.util.Map<String, Object>> getListMap(){List<java.util.Map<String, Object>> list = new ArrayList<Map<String,Object>>();java.util.Map<String,Object> map1 = new HashMap<String,Object>();map1.put("id",1001);map1.put("name","刘德华");map1.put("address","香港");java.util.Map<String,Object> map2 = new HashMap<String,Object>();map2.put("id",1002);map2.put("name","宋慧乔");map2.put("address","韩国");list.add(map1);list.add(map2);return list;}}

4.TestJson.java

package com.json.test;import com.json.service.JsonService;import com.json.tools.JsonTools;public class TestJson {public TestJson() {// TODO Auto-generated constructor stub}/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stub//Test1 Person System.out.println("Json数据格式测试结果：\n");String jsonString1 = JsonTools.creatJsonString("person", JsonService.getPerson());//Test2 personsString jsonString2 = JsonTools.creatJsonString("persons", JsonService.getListPersons());//Test3 listStringString jsonString3 = JsonTools.creatJsonString("listString",JsonService.getListString());//Test 4 listMapString jsonString4 = JsonTools.creatJsonString("listMap",JsonService.getListMap());System.out.println("测试结果1："+jsonString1+"\n");System.out.println("测试结果2："+jsonString2+"\n");System.out.println("测试结果3："+jsonString3+"\n");System.out.println("测试结果4："+jsonString4);}}

5.JsonTools.java

package com.json.tools;import net.sf.json.JSONObject;public class JsonTools {/** * @param key 表示json字符串的头信息 * @param value 表示解析几何的类型 * @return */public static String creatJsonString(String key, Object value) {JSONObject jsonObject = new JSONObject();jsonObject.put(key, value);return jsonObject.toString();}}