Java Json 序列化與反序列化

jopen 10年前發布 | 72K 次閱讀 JSON JSON開發包

JSON</strong>(JavaScript Object Notation) 是一種輕量級的數據交換格式。 易于人閱讀和編寫。同時也易于機器解析和生成。 它基于JavaScript Programming Language, Standard ECMA-262 3rd Edition

  • December 1999的一個子集。 JSON采用完全獨立于語言的文本格式，這些特性使JSON成為理想的數據交換語言。</span>


    下面介紹兩款自己在開發中常用的處理Json的Java開源類庫：Gson和Fastjson

    1、Gson

    Gson is a Java library that can be used to convert Java Objects into their JSON representation. It can also be used to convert a JSON string to an equivalent Java object. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of.

    Gson官網：http://code.google.com/p/google-gson/

    Gson User Guide：https://sites.google.com/site/gson/gson-user-guide



    2、Fastjson

    Fastjson是一個json處理工具包，由阿里巴巴公司開發，包括“序列化”和“反序列化”兩部分，它具備如下特征：

    1. 速度最快，測試表明，fastjson具有極快的性能，超越任其他的java json parser。包括自稱最快的jackson。
    2. 功能強大，完全支持java bean、集合、Map、日期、Enum，支持范型，支持自省。
    3. 無依賴，能夠直接運行在Java SE 5.0以上版本
    4. 支持Android。
    5. 開源 (Apache 2.0)


    下面通過一個簡單Demo，對比兩者 序列化與反序列化的用法

    JavaBean 實體Person

        package com.example.testjson.entity;
    

    import java.util.Date;
    
 import java.util.List;
    
 import java.util.Map;
    

    public class Person {
    


     private String name;  
 private FullName fullName;  
 private int age;  
 private Date birthday;  
 private List<String> hobbies;  
 private Map<String, String> clothes;  
 private List<Person> friends;  

 public String getName() {  
     return name;  
 }  

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

 public FullName getFullName() {  
     return fullName;  
 }  

 public void setFullName(FullName fullName) {  
     this.fullName = fullName;  
 }  

 public int getAge() {  
     return age;  
 }  

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

 public Date getBirthday() {  
     return birthday;  
 }  

 public void setBirthday(Date birthday) {  
     this.birthday = birthday;  
 }  

 public List<String> getHobbies() {  
     return hobbies;  
 }  

 public void setHobbies(List<String> hobbies) {  
     this.hobbies = hobbies;  
 }  

 public Map<String, String> getClothes() {  
     return clothes;  
 }  

 public void setClothes(Map<String, String> clothes) {  
     this.clothes = clothes;  
 }  

 public List<Person> getFriends() {  
     return friends;  
 }  

 public void setFriends(List<Person> friends) {  
     this.friends = friends;  
 }  

 @Override  
 public String toString() {  
     String str= "Person [name=" + name + ", fullName=" + fullName + ", age="  
             + age + ", birthday=" + birthday + ", hobbies=" + hobbies  
             + ", clothes=" + clothes +  "]\n";  
     if(friends!=null){  
         str+="Friends:\n";  
         for (Person f : friends) {  
             str+="\t"+f;  
         }  
     }  
     return str;  
 }  


    

    }
    

    class FullName {
    


     private String firstName;  
 private String middleName;  
 private String lastName;  

 public FullName(){  
 }  

 public FullName(String firstName, String middleName, String lastName) {  
     super();  
     this.firstName = firstName;  
     this.middleName = middleName;  
     this.lastName = lastName;  
 }  

 public String getFirstName() {  
     return firstName;  
 }  

 public void setFirstName(String firstName) {  
     this.firstName = firstName;  
 }  

 public String getMiddleName() {  
     return middleName;  
 }  

 public void setMiddleName(String middleName) {  
     this.middleName = middleName;  
 }  

 public String getLastName() {  
     return lastName;  
 }  

 public void setLastName(String lastName) {  
     this.lastName = lastName;  
 }  

 @Override  
 public String toString() {  
     return "[firstName=" + firstName + ", middleName="  
             + middleName + ", lastName=" + lastName + "]";  
 }  


    

    }  </pre></div>
</div>
</div>

    

    
</div>

    負責創建Person的Bean Factory
    

        package com.example.testjson.entity;
    

    import java.util.ArrayList;
    
 import java.util.HashMap;
    
 import java.util.List;
    
 import java.util.Map;
    

    public class PersonFactory {
    


     private static Person createABSPerson(String name,List<Person> friends) {  
     Person newPerson = new Person();  
     newPerson.setName(name);  
     newPerson.setFullName(new FullName(name+"_first", name+"_middle", name+"_last"));  
     newPerson.setAge(24);  
     List<String> hobbies=new ArrayList<String>();  
     hobbies.add("籃球");  
     hobbies.add("游泳");  
     hobbies.add("coding");  
     newPerson.setHobbies(hobbies);  
     Map<String,String> clothes=new HashMap<String, String>();  
     clothes.put("coat", "Nike");  
     clothes.put("trousers", "adidas");  
     clothes.put("shoes", "安踏");  
     newPerson.setClothes(clothes);  
     newPerson.setFriends(friends);  
     return newPerson;  
 }  

 public static Person create(String name){  
     List<Person> friends=new ArrayList<Person>();  
     friends.add(createABSPerson("小明",null));  
     friends.add(createABSPerson("Tony",null));  
     friends.add(createABSPerson("陳小二",null));  

     return createABSPerson(name,friends);  
 }  

    

    }  </pre></div>
</div>
</div>

    

    
</div>

    Gson 工具類GsonUtil
    


    

    

    
</div>
</div>

        package com.example.testjson.gson;
    

    import com.google.gson.Gson;
    
 import com.google.gson.GsonBuilder;
    
 import com.google.gson.JsonElement;
    
 import com.google.gson.JsonParser;
    

    public class GsonUtil {
    
 private static Gson gson = new GsonBuilder().create();
    


     public static String bean2Json(Object obj){  
     return gson.toJson(obj);  
 }  

 public static <T> T json2Bean(String jsonStr,Class<T> objClass){  
     return gson.fromJson(jsonStr, objClass);  
 }  

 public static String jsonFormatter(String uglyJsonStr){  
     Gson gson = new GsonBuilder().setPrettyPrinting().create();  
     JsonParser jp = new JsonParser();  
     JsonElement je = jp.parse(uglyJsonStr);  
     String prettyJsonString = gson.toJson(je);  
     return prettyJsonString;  
 }  

    

    }  </pre>
    

    
</div>


    

    

    Fastjson 工具類FastJsonUtil
    


    

    

    
</div>
</div>

        package com.example.testjson.fastjson;
    

    import com.alibaba.fastjson.JSON;
    

    public class FastJsonUtil {
    


     public static String bean2Json(Object obj){  
     return JSON.toJSONString(obj);  
 }  

 public static <T> T json2Bean(String jsonStr,Class<T> objClass){  
     return JSON.parseObject(jsonStr, objClass);  
 }  

    

    }  </pre>
    

    
</div>

    最后兩個測試類
    


    

    

    GsonTest
    

    

        package com.example.testjson;
    

    import com.example.testjson.entity.Person;
    
 import com.example.testjson.entity.PersonFactory;
    
 import com.example.testjson.gson.GsonUtil;
    

    public class GsonTest {
    


     /** 
  * @param args 
  */  
 public static void main(String[] args) {  
     // TODO Auto-generated method stub  
     Person p = PersonFactory.create("Kobe");  
     String json = GsonUtil.bean2Json(p);  
     String prettyJsonString = GsonUtil.jsonFormatter(json);  

     System.out.println("FastJson Serializing="+json);  
     System.out.println("FastJson Serializing PrettyPrinting="+prettyJsonString);  

     Person newPerson = GsonUtil.json2Bean(json, Person.class);  

     System.out.println("FastJson Deserializing="+newPerson);  
 }  


    

    }  </pre></div>
</div>
</div>

    

    
</div>

    FastJsonTest
    

    

    

    package com.example.testjson;

import com.example.testjson.entity.Person;
import com.example.testjson.entity.PersonFactory;
import com.example.testjson.fastjson.FastJsonUtil;

public class FastJsonTest {

/** 
 * @param args 
 */  
public static void main(String[] args) {  
    // TODO Auto-generated method stub  

    Person p = PersonFactory.create("Kobe");  
    String json = FastJsonUtil.bean2Json(p);  

    System.out.println("FastJson Serializing="+json);  

    Person newPerson = FastJsonUtil.json2Bean(json, Person.class);  

    System.out.println("FastJson Deserializing="+newPerson);  
}

} </pre></div> </div> </div>

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