本文讲解2点：
1. fastjson生成和解析json数据
(举例：4种常用类型:JavaBean,List<JavaBean>,List<String>,List<Map<String,Object>)
2.通过一个android程序测试fastjson的用法。
fastjson简介：
Fastjson是一个Java语言编写的高性能功能完善的JSON库。fastjson采用独创的算法，将parse的速度提升到极致，超过所有json库，包括曾经号称最快的jackson。并且还超越了google的二进制协议protocol buf。Fastjson完全支持http://json.org的标准，也是官方网站收录的参考实现之一。支持各种JDK类型。包括基本类型、JavaBean、Collection、Map、Enum、泛型等。支持JDK 5、JDK 6、Android、阿里云手机等环境。
一. fastjson生成json字符串(JavaBean,List<JavaBean>,List<String>,List<Map<String,Object>)
String jsonStrng = JSON.toJSONString(object);
二. fastjson 解析json字符串为四种类型
1. JavaBean
Person person = JSON.parseObject(jsonString, Person.class);
2. List<JavaBean>
List<Person> listPerson =JSON.parseArray(jsonString, Person.class);
3. List<String>
List<String> listString = JSON.parseArray(jsonString, String.class);
4. List<Map<String,Object>>
List<Map<String, Object>> listMap = JSON.parseObject(jsonString, new TypeReference<List<Map<String,Object>>>(){}); (注意：此处可看出fastjson反射机制比gson更准确， id = 1001 通过fastjson反射仍是 id = 1001 , 而通过gson反射结果 为 id =1001.0 ,参考前篇程序运行结果图GSON方式生成和解析json数据)
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程序运行结果：
1. 点击“解析Person数据”按钮
2. 点击“解析Persons数据按钮”
3.点击“解析listString数据”按钮
4.点击“解析listMap数据”按钮
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客户端eclipse android工程目录（左边）服务器端myeclipse web工程（右边）
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服务器端 fastjson_Project
1.FastJsonAction.java
package com.fastjson.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.fastjson.service.FastJsonService;
import com.fastjson.tools.*;
public class FastJsonAction extends HttpServlet {
/**
* 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");
String action_flag = request.getParameter("action_flag");
PrintWriter out = response.getWriter();
if ("person".equals(action_flag)) {
// String person = GsonTools.creatJsonString(GsonService.getPerson());
String person = FastJsonTools.createJsonString(FastJsonService.getPerson());
out.println(person);
System.out.println(person);
} else if("persons".equals(action_flag)) {
// String persons = GsonTools.creatJsonString(GsonService.getListPersons());
String persons = FastJsonTools.createJsonString(FastJsonService.getListPersons());
out.println(persons);
System.out.println(persons);
}else if("listString".equals(action_flag)) {
// String listString = GsonTools.creatJsonString(GsonService.getListString());
String listString = FastJsonTools.createJsonString(FastJsonService.getListString());
out.println(listString);
System.out.println(listString);
}else if("listMap".equals(action_flag)) {
// String listMap = GsonTools.creatJsonString(GsonService.getListMap());
String listMap = FastJsonTools.createJsonString(FastJsonService.getListMap());
out.println(listMap);
System.out.println(listMap);
}
System.out.println();
out.flush();
out.close();
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
}
2.FastJsonService.java
package com.fastjson.service;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.fastjson.data.Person;
public class FastJsonService {
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;
}
}
3.FastJsonTools.java
package com.fastjson.tools;
import com.alibaba.fastjson.*;
public class FastJsonTools {
public static String createJsonString(Object object){
String jsonString = "";
try {
jsonString = JSON.toJSONString(object);
} catch (Exception e) {
// TODO: handle exception
}
return jsonString;
}
}
4.Person.java
package com.fastjson.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;
}
@Override
public String toString() {
return "Person [id=" + id + ", name=" + name + ", address=" + address
+ "]";
}
}
5. TestFastJson.java
package com.fastjson.test;
import com.fastjson.service.FastJsonService;
import com.fastjson.tools.FastJsonTools;
public class TestFastJson {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
//Test1 Person
System.out.println("FastJson数据格式测试结果：\n");
String person = FastJsonTools.createJsonString(FastJsonService.getPerson());
//Test2 persons
String listPerson = FastJsonTools.createJsonString(FastJsonService.getListPersons());
//Test3 listString
String listString = FastJsonTools.createJsonString(FastJsonService.getListString()) ;
//Test 4 listMap
String listMap = FastJsonTools.createJsonString(FastJsonService.getListMap()) ;
System.out.println("测试结果1："+person+"\n");
System.out.println("测试结果2："+listPerson+"\n");
System.out.println("测试结果3："+listString+"\n");
System.out.println("测试结果4："+listMap);
}
}
客户端：android_fastjson
1.MainActivity.java
package com.android.mygson;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.Serializable;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.List;
import java.util.Map;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import com.fastjson.tools.FastJsonTools;
import com.gson.data.Person;
import com.gson.http.HttpUtils;
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;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
closeStrictMode();//关闭严苛模式
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);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.person:
String url_path = "http://192.168.0.102:8080/fastjson_Project/servlet/FastJsonAction?action_flag=person";
String jsonString = HttpUtils.getJsonContent(url_path, "utf-8");
Person person = FastJsonTools.getPerson(jsonString, Person.class);
//用fastJson技术解析json字符串，转换为Person对象
// Person person = JSON.parseObject(jsonString, Person.class);
Intent intent = new Intent(MainActivity.this, OtherActivity.class);
intent.putExtra("click_flag", "person");
intent.putExtra("person", (Serializable) person);
startActivity(intent);
// Log.i(TAG, person.toString());
break;
case R.id.persons:
String url_path2 = "http://192.168.0.102:8080/fastjson_Project/servlet/FastJsonAction?action_flag=persons";
String jsonString2 = HttpUtils.getJsonContent(url_path2, "utf-8");
// 用fastjson 将json字符串转换成 List<Person>
// List<Person> listPerson =JSON.parseArray(jsonString2, Person.class);
List<Person> listPerson =FastJsonTools.getPersons(jsonString2, Person.class);
Intent intent2 = new Intent(MainActivity.this, OtherActivity.class);
intent2.putExtra("click_flag", "persons");
intent2.putExtra("persons", (Serializable) listPerson); // 用Intent传递 List<Person>数据类型
startActivity(intent2);
break;
case R.id.listString:
String url_path3 = "http://192.168.0.102:8080/fastjson_Project/servlet/FastJsonAction?action_flag=listString";
String jsonString3 = HttpUtils.getJsonContent(url_path3, "utf-8");
// 用fastjson 将json字符串转换成 List<String>
// List<String> listString = JSON.parseArray(jsonString3, String.class);
List<String> listString = FastJsonTools.getPersons(jsonString3,String.class);
Intent intent3 = new Intent(MainActivity.this, OtherActivity.class);
intent3.putExtra("click_flag", "listString");
intent3.putExtra("listString", (Serializable) listString); // 用Intent传递 List<Person>数据类型
startActivity(intent3);
break;
case R.id.listMap:
String url_path4 = "http://192.168.0.102:8080/fastjson_Project/servlet/FastJsonAction?action_flag=listMap";
String jsonString4 = HttpUtils.getJsonContent(url_path4, "utf-8");
// 用fastjson 将json字符串转换成 List<Map<String,Object>>
// List<Map<String, Object>> listMap = JSON.parseObject(jsonString4, new TypeReference<List<Map<String,Object>>>(){});
List<Map<String, Object>> listMap = FastJsonTools.getListMap(jsonString4);
Intent intent4 = new Intent(MainActivity.this, OtherActivity.class);
intent4.putExtra("click_flag", "listMap");
intent4.putExtra("listMap", (Serializable) listMap); // 用Intent传递 List<Map<Sting,Object>>数据类型
intent4.putExtra("jsonString", jsonString4);
startActivity(intent4);
break;
}
}
@SuppressLint("NewApi")
public static void closeStrictMode() {
StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
.detectAll().penaltyLog().build());
}
private static String changeInputStream(InputStream inputStream , String encode) throws IOException {
// TODO Auto-generated method stub
String 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;
}
}
2.OtherActivity.java
package com.android.mygson;
import java.util.List;
import java.util.Map;
import com.gson.data.Person;
import android.R.integer;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
public class OtherActivity extends Activity {
private TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.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());
// textView.setText("test :"+intent.getStringExtra("test"));
} 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Map
for (Map.Entry<String, Object> entry : map.entrySet()) {
String key = entry.getKey();
Object value = entry.getValue();
listMapString += " " + key + " : " + value + " ";
}
listMapString += "\n";
}
textView.setText(listMapString+intent.getStringExtra("jsonString"));
}
}
}
3.FastJsonTools.java
package com.fastjson.tools;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
public class FastJsonTools {
/**
* 用fastjson 将json字符串解析为一个 JavaBean
*
* @param jsonString
* @param cls
* @return
*/
public static <T> T getPerson(String jsonString, Class<T> cls) {
T t = null;
try {
t = JSON.parseObject(jsonString, cls);
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
return t;
}
/**
* 用fastjson 将json字符串 解析成为一个 List<JavaBean> 及 List<String>
*
* @param jsonString
* @param cls
* @return
*/
public static <T> List<T> getPersons(String jsonString, Class<T> cls) {
List<T> list = new ArrayList<T>();
try {
list = JSON.parseArray(jsonString, cls);
} catch (Exception e) {
// TODO: handle exception
}
return list;
}
/**
* 用fastjson 将jsonString 解析成 List<Map<String,Object>>
*
* @param jsonString
* @return
*/
public static List<Map<String, Object>> getListMap(String jsonString) {
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
try {
// 两种写法
// list = JSON.parseObject(jsonString, new
// TypeReference<List<Map<String, Object>>>(){}.getType());
list = JSON.parseObject(jsonString,
new TypeReference<List<Map<String, Object>>>() {
});
} catch (Exception e) {
// TODO: handle exception
}
return list;
}
}
4.Person.java
package com.gson.data;
import java.io.Serializable;
public class Person implements Serializable{
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;
}
@Override
public String toString() {
return "Person [id=" + id + ", name=" + name + ", address=" + address
+ "]";
}
}
5.HttpUtils.java
package com.gson.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;
/** 接收path服务器端返回的 InputStream, 转换为 json字符串
* @author ben
*
*/
public class HttpUtils {
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 stub
String 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;
}
}
6.activity_matin.xml
<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"> <Button android:id="@+id/person" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="解析Person数据" /> <Button android:id="@+id/persons" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="解析Persons数据" /> <Button android:id="@+id/listString" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="解析listString数据" /> <Button android:id="@+id/listMap" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="解析listMap数据" /> </LinearLayout>
7.activity_other.xml
<?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>
8.AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.android.mygson" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="19" /> <!-- 添加访问网络的授权 --> <uses-permission android:name="android.permission.INTERNET" /> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name="com.android.mygson.MainActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name=".OtherActivity"></activity> </application> </manifest>
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注意一点：
泛型方法
客户端：FastJsonToos.java 泛型方法的写法。