Gson、FastJson、json-lib对比与实例

一、各个JSON技术的对比（本部分摘抄自http://www.cnblogs.com/kunpengit/p/4001680.html）：

1.json-lib
json-lib最开始的也是应用最广泛的json解析工具，json-lib 不好的地方确实是依赖于很多第三方包，
包括commons-beanutils-1.7.0.jar，commons-collections-3.2.jar，commons-lang-2.4.jar，commons-logging-1.1.jar，ezmorph-1.0.4.jar，jdom.jar，json-lib-2.2.2-jdk15.jar
对于复杂类型的转换，json-lib对于json转换成bean还有缺陷，比如一个类里面会出现另一个类的list或者map集合，json-lib从json到bean的转换就会出现问题。
json-lib在功能和性能上面都不能满足现在互联网化的需求。
2.开源的Jackson
相比json-lib框架，Jackson所依赖的jar包较少，简单易用并且性能也要相对高些。
而且Jackson社区相对比较活跃，更新速度也比较快。
Jackson对于复杂类型的json转换bean会出现问题，一些集合Map，List的转换出现问题。
Jackson对于复杂类型的bean转换Json，转换的json格式不是标准的Json格式
3.Google的Gson
Gson是目前功能最全的Json解析神器，Gson当初是为因应Google公司内部需求而由Google自行研发而来，
但自从在2008年五月公开发布第一版后已被许多公司或用户应用。
Gson的应用主要为toJson与fromJson两个转换函数，无依赖，不需要例外额外的jar，只依赖于gson-2.7.jar，能够直接跑在JDK上。
而在使用这种对象转换之前需先创建好对象的类型以及其成员才能成功的将JSON字符串成功转换成相对应的对象。
类里面只要有get和set方法，Gson完全可以将复杂类型的json到bean或bean到json的转换，是JSON解析的神器。
Gson在功能上面无可挑剔，但是性能上面比FastJson有所差距。
4.阿里巴巴的FastJson
Fastjson是一个Java语言编写的高性能的JSON处理器,由阿里巴巴公司开发。
无依赖，不需要例外额外的jar，只需要fastjson-1.2.8.jar，能够直接跑在JDK上。
FastJson在复杂类型的Bean转换Json上会出现一些问题，可能会出现引用的类型，导致Json转换出错，需要制定引用。
FastJson采用独创的算法，将parse的速度提升到极致，超过所有json库。

综上4种Json技术的比较，在项目选型的时候可以使用Google的Gson和阿里巴巴的FastJson两种并行使用，
如果只是功能要求，没有性能要求，可以使用google的Gson，
如果有性能上面的要求可以使用Gson将bean转换json确保数据的正确，使用FastJson将Json转换Bean

二、实例

1.首先建立实体Bean

（1）学生实体类

 1 package com.model;
 2 
 3 import java.io.Serializable;
 4 import java.util.Date;
 5 
 6 /**
 7   * @ClassName: Student 
 8   * @Description: TODO(学生实体类) 
 9   * @author xbq 
10   * @date 2017-2-2 上午9:31:06 
11   *
12  */
13 public class Student implements Serializable{
14 
15     /** 
16      * @Fields serialVersionUID : TODO(用一句话描述这个变量表示什么) 
17     */ 
18     private static final long serialVersionUID = 1L;
19     
20     private int id;
21     private String name;
22     private Date birth;
23     private String address;
24     
25     public Student() {
26         super();
27     }
28     
29     public Student(int id, String name, Date birth, String address) {
30         super();
31         this.id = id;
32         this.name = name;
33         this.birth = birth;
34         this.address = address;
35     }
36 
37     public int getId() {
38         return id;
39     }
40     public void setId(int id) {
41         this.id = id;
42     }
43     public String getName() {
44         return name;
45     }
46     public void setName(String name) {
47         this.name = name;
48     }
49     public Date getBirth() {
50         return birth;
51     }
52     public void setBirth(Date birth) {
53         this.birth = birth;
54     }
55     public String getAddress() {
56         return address;
57     }
58     public void setAddress(String address) {
59         this.address = address;
60     }
61     
62     @Override
63     public String toString() {
64         return "Student [id=" + id + ", name=" + name + ", birth=" + birth
65                 + ", address=" + address + "]";
66     }
67     
68 }
View Code

（2）包含学生List的实体类

 1 package com.model;
 2 
 3 import java.io.Serializable;
 4 import java.util.List;
 5 
 6 /**
 7  * 
 8  * @ClassName: StudentAnalysis 
 9  * @Description: TODO(包含学生 实体类 的List的 实体类) 
10  * @author xbq 
11  * @date 2017-2-2 上午9:31:46 
12  *
13  */
14 public class StudentAnalysis implements Serializable{
15 
16     /** 
17     * @Fields serialVersionUID : TODO(用一句话描述这个变量表示什么) 
18     */ 
19     private static final long serialVersionUID = 1L;
20     private List<Student> students;
21     
22     public StudentAnalysis() {
23         super();
24     }
25     
26     public StudentAnalysis(List<Student> students) {
27         super();
28         this.students = students;
29     }
30 
31     public List<Student> getStudents() {
32         return students;
33     }
34     public void setStudents(List<Student> students) {
35         this.students = students;
36     }
37 
38     @Override
39     public String toString() {
40         return "StudentAnalysis [students=" + students + "]";
41     }
42     
43 }
View Code

2.Gson测试类和封装的工具类

（1）测试类

  1 package com.gson.test;
  2 
  3 import java.util.ArrayList;
  4 import java.util.Date;
  5 import java.util.HashMap;
  6 import java.util.List;
  7 import java.util.Map;
  8 
  9 import org.junit.Test;
 10 
 11 import com.google.gson.Gson;
 12 import com.google.gson.GsonBuilder;
 13 import com.google.gson.reflect.TypeToken;
 14 import com.model.Student;
 15 import com.model.StudentAnalysis;
 16 
 17 /**
 18  * @ClassName: TestGson 
 19  * @Description: TODO(这里用一句话描述这个类的作用) 
 20  * @author xbq 
 21  * @date 2017-2-2 上午9:37:46 
 22  * Gson将 实体中的 Timestamp 类型 在 json中转化为   Feb 2, 2017 9:36:41 AM 形式
 23  *            Date 类型 在 json中转化为   Feb 2, 2017 9:36:41 AM 形式
 24  */
 25 public class TestGson {
 26     
 27     /**
 28      * @Title: testObjectToJson 
 29      * @Description: TODO(对象转Json) 
 30      * @param     设定文件 
 31      * @return void    返回类型 
 32      * @throws
 33      */
 34     @Test
 35     public void testObjectToJson(){
 36         Gson gson = new GsonBuilder().serializeNulls().create();  // 这样实例化 会将 实体中空的属性 在 json中显示为 null
 37         Student student = new Student(10,"张三",new Date(),null);
 38         String json = gson.toJson(student);
 39         System.out.println("json==" + json);
 40         
 41         List<Student> list = new ArrayList<Student>();
 42         student = new Student(1,"张三",new Date(),null);
 43         list.add(student);
 44         student = new Student(2,"李四",new Date(),null);
 45         list.add(student);
 46         student = new Student(3,"王五",null,"山东");
 47         list.add(student);
 48         StudentAnalysis analysis = new StudentAnalysis(list);
 49         String studentsJson = gson.toJson(analysis);
 50         System.out.println("json==" + studentsJson);
 51         
 52     }
 53     
 54     
 55     @Test
 56     public void jsonToObject(){
 57         Gson gson = new GsonBuilder().serializeNulls().create();
 58         String stuJson = "{"id":10,"name":"张三","birth":"Feb 2, 2017 9:46:39 AM","createDate":"Feb 2, 2017 9:46:39 AM","address":null}";
 59         Student stu = gson.fromJson(stuJson, Student.class);
 60         System.out.println("student==" + stu);
 61         
 62         String stuListJson = "{"students":[{"id":1,"name":"张三","birth":"Feb 2, 2017 9:46:39 AM","createDate":"Feb 2, 2017 9:46:39 AM","address":null},{"id":2,"name":"李四","birth":"Feb 2, 2017 9:46:39 AM","createDate":null,"address":null},{"id":3,"name":"王五","birth":null,"createDate":"Feb 2, 2017 9:46:39 AM","address":"山东"}]}";
 63         StudentAnalysis analysis = gson.fromJson(stuListJson, StudentAnalysis.class);
 64         System.out.println("studentList==" + analysis);
 65         
 66         // 遍历List
 67         for(Student s : analysis.getStudents()){
 68             System.out.println(s);
 69         }
 70         
 71         String studentsJson = gson.toJson(analysis);
 72         System.out.println("json==" + studentsJson);
 73         
 74     }
 75     
 76     @Test
 77     public void ListToJson(){
 78         Gson gson = new GsonBuilder().serializeNulls().create();
 79         
 80         List<Student> list = new ArrayList<Student>();
 81         Student student = new Student(1,"张三",new Date(),null);
 82         list.add(student);
 83         student = new Student(2,"李四",new Date(),null);
 84         list.add(student);
 85         student = new Student(3,"王五",null,"山东");
 86         list.add(student);
 87         // list 转为 json
 88         String json = gson.toJson(list);
 89         System.out.println(json);
 90         
 91         // json转为 List
 92         List<Student> students = gson.fromJson(json, new TypeToken<List<Student>>(){}.getType());  
 93         System.out.println(students);
 94     }
 95     
 96     @Test
 97     public void MapToJson(){
 98         Gson gson = new GsonBuilder().serializeNulls().create();
 99         
100         Map<String,List<Student>> map = new HashMap<String,List<Student>>();
101         List<Student> list1 = new ArrayList<Student>();
102         Student student = new Student(1,"张三",new Date(),null);
103         list1.add(student);
104         student = new Student(2,"李四",new Date(),null);
105         list1.add(student);
106         student = new Student(3,"王五",null,"山东");
107         list1.add(student);
108         
109         List<Student> list2 = new ArrayList<Student>();
110         student = new Student(4,"张三2",new Date(),null);
111         list2.add(student);
112         student = new Student(5,"李四2",new Date(),null);
113         list2.add(student);
114         student = new Student(6,"王五2",null,"山东");
115         list2.add(student);
116         
117         List<Student> list3 = new ArrayList<Student>();
118         student = new Student(7,"张三2",new Date(),null);
119         list3.add(student);
120         student = new Student(8,"李四2",new Date(),null);
121         list3.add(student);
122         student = new Student(9,"王五2",null,"山东");
123         list3.add(student);
124         
125         map.put("list1", list1);
126         map.put("list2", list2);
127         map.put("list3", list3);
128         
129         // map转为 json
130         String json = gson.toJson(map);
131         System.out.println(json);
132         
133         // json转为map
134         map = gson.fromJson(json, new TypeToken<HashMap<String,List<Student>>>(){}.getType());
135         System.out.println(map);
136     }
137     
138 }
View Code

（2）工具类（在项目中可以直接使用）

  1 package com.gson.util;
  2 
  3 import java.lang.reflect.Type;
  4 import java.util.ArrayList;
  5 import java.util.Date;
  6 import java.util.HashMap;
  7 import java.util.List;
  8 import java.util.Map;
  9 
 10 import com.google.gson.Gson;
 11 import com.google.gson.GsonBuilder;
 12 import com.google.gson.reflect.TypeToken;
 13 import com.model.Student;
 14 import com.model.StudentAnalysis;
 15 
 16 /**
 17  * @ClassName: GsonUtil 
 18  * @Description: TODO(这里用一句话描述这个类的作用) 
 19  * @author xbq 
 20  * @date 2017-2-2 下午12:42:59 
 21  *Gson将 实体中的 Timestamp 类型 在 json中转化为   Feb 2, 2017 9:36:41 AM 形式
 22  *            Date 类型 在 json中转化为   Feb 2, 2017 9:36:41 AM 形式
 23  */
 24 public class GsonUtil {
 25 
 26     private static Gson gson = null;
 27     
 28     static {
 29         gson = new GsonBuilder().serializeNulls().create();  // 这样实例化 会将 实体中空的属性 在 json中显示为 null
 30     }
 31     
 32     /**
 33      * @Title: objectToJson 
 34      * @Description: TODO(实体类、List、Map 转为 Json) 
 35      * @param @param obj
 36      * @param @return    设定文件 
 37      * @return String    返回类型 
 38      * @throws
 39      */
 40     public static String objectToJson(Object obj){
 41         return gson.toJson(obj);
 42     }
 43     
 44     /**
 45      * @Title: jsonToObject 
 46      * @Description: TODO(Json转化为实体类 或 List、Map) 
 47      * @param @param json
 48      * @param @param type
 49      * @param @return    设定文件 
 50      * @return Object    返回类型 
 51      * @throws
 52      */
 53     public static Object jsonToObject(String json,Type type){
 54         if(type instanceof List){
 55             return gson.fromJson(json, new TypeToken<List<Type>>(){}.getType());  
 56         }else if(type instanceof Map){
 57             return gson.fromJson(json, new TypeToken<HashMap<String,List<Type>>>(){}.getType());
 58         }else {
 59             return gson.fromJson(json, type);
 60         }
 61     }
 62     
 63     
 64     /**
 65      * 测试
 66      * @Title: main 
 67      * @Description: TODO(这里用一句话描述这个方法的作用) 
 68      * @param @param args    设定文件 
 69      * @return void    返回类型 
 70      * @throws
 71      */
 72     public static void main(String[] args) {
 73         Student student = new Student(10,"张三",new Date(),null);
 74         String json = objectToJson(student);
 75         System.out.println("---1---学生Student实体转为的Json------");
 76         System.out.println(json);
 77         
 78         List<Student> list = new ArrayList<Student>();
 79         student = new Student(1,"张三",new Date(),null);
 80         list.add(student);
 81         student = new Student(2,"李四",new Date(),null);
 82         list.add(student);
 83         student = new Student(3,"王五",null,"山东");
 84         list.add(student);
 85         StudentAnalysis analysis = new StudentAnalysis(list);
 86         String studentsJson = objectToJson(analysis);
 87         System.out.println("---2----学生StudentAnalysis实体转为的Json------");
 88         System.out.println(studentsJson);
 89         
 90         
 91         String stuJson = "{"id":10,"name":"张三","birth":"Feb 2, 2017 9:46:39 AM","address":null}";
 92         Student stu = (Student) jsonToObject(stuJson, Student.class);
 93         System.out.println("---3----学生Json转化为Student实体-------");
 94         System.out.println(stu);
 95         
 96         String stuListJson = "{"students":[{"id":1,"name":"张三","birth":"Feb 2, 2017 9:46:39 AM","address":null},{"id":2,"name":"李四","birth":"Feb 2, 2017 9:46:39 AM","createDate":null,"address":null},{"id":3,"name":"王五","birth":null,"createDate":"Feb 2, 2017 9:46:39 AM","address":"山东"}]}";
 97         StudentAnalysis analysis1 = (StudentAnalysis) jsonToObject(stuListJson, StudentAnalysis.class);
 98         System.out.println("---4----学生analysis1转化为StudentAnalysis实体-------");
 99         System.out.println(analysis1);
100         
101         System.out.println("---5----遍历学生List--------");
102         // 遍历List
103         for(Student s : analysis1.getStudents()){
104             System.out.println(s);
105         }
106         
107     }
108 }
View Code

3.FastJson测试类和封装的工具类

（1）测试类

  1 package com.fastjson.test;
  2 
  3 import java.util.ArrayList;
  4 import java.util.Date;
  5 import java.util.HashMap;
  6 import java.util.List;
  7 import java.util.Map;
  8 
  9 import org.junit.Test;
 10 
 11 import com.alibaba.fastjson.JSON;
 12 import com.alibaba.fastjson.TypeReference;
 13 import com.alibaba.fastjson.serializer.SerializerFeature;
 14 import com.model.Student;
 15 import com.model.StudentAnalysis;
 16 
 17 /**
 18  * fastjson 将 Date 和 Timestamp 类型的 转化为 long的形式
 19  * @ClassName: TestFastJson 
 20  * @Description: TODO(这里用一句话描述这个类的作用) 
 21  * @author xbq 
 22  * @date 2017-2-2 下午2:00:27 
 23  *
 24  */
 25 public class TestFastJson {
 26 
 27     @Test
 28     public void ObjectToJson(){
 29         Student student = new Student(10,"张三",new Date(),null);
 30         //  缺省情况下FastJSON不输入为值Null的字段，可以使用SerializerFeature.WriteMapNullValue使其输出
 31         String json = JSON.toJSONString(student,SerializerFeature.WriteMapNullValue);
 32         System.out.println(json);
 33         
 34         List<Student> list = new ArrayList<Student>();
 35         student = new Student(1,"张三",new Date(),null);
 36         list.add(student);
 37         student = new Student(2,"李四",new Date(),null);
 38         list.add(student);
 39         student = new Student(3,"王五",null,"山东");
 40         list.add(student);
 41         StudentAnalysis analysis = new StudentAnalysis(list);
 42         json = JSON.toJSONString(analysis,SerializerFeature.WriteMapNullValue);
 43         System.out.println(json);
 44     }
 45     
 46     @Test
 47     public void jsonToObject(){
 48         String json = "{"address":null,"birth":1486015195815,"createDate":1486015195815,"id":10,"name":"张三"}";
 49         Student student =  JSON.parseObject(json,Student.class);
 50         System.out.println(student);
 51         
 52         json = "{"students":[{"address":null,"birth":1486015524472,"createDate":1486015524472,"id":1,"name":"张三"},{"address":null,"birth":1486015524472,"createDate":null,"id":2,"name":"李四"},{"address":"山东","birth":null,"createDate":1486015524472,"id":3,"name":"王五"}]}";
 53         StudentAnalysis analysis = JSON.parseObject(json,StudentAnalysis.class);
 54         System.out.println(analysis);
 55     }
 56     
 57     @Test
 58     public void ListToJson(){
 59         List<Student> list = new ArrayList<Student>();
 60         Student student = new Student(1,"张三",new Date(),null);
 61         list.add(student);
 62         student = new Student(2,"李四",new Date(),null);
 63         list.add(student);
 64         student = new Student(3,"王五",null,"山东");
 65         list.add(student);
 66         
 67         // list转化为 json 数组
 68         String json = JSON.toJSONString(list,SerializerFeature.WriteMapNullValue);
 69         System.out.println(json);
 70         
 71         // json数组转为 list
 72         List<Student> list1 = JSON.parseArray(json, Student.class);
 73         System.out.println(list1);
 74     }
 75     
 76     
 77     @Test
 78     public void MapToJson(){
 79         Map<String,List<Student>> map = new HashMap<String,List<Student>>();
 80         List<Student> list1 = new ArrayList<Student>();
 81         Student student = new Student(1,"张三",new Date(),null);
 82         list1.add(student);
 83         student = new Student(2,"李四",new Date(),null);
 84         list1.add(student);
 85         student = new Student(3,"王五",null,"山东");
 86         list1.add(student);
 87         
 88         List<Student> list2 = new ArrayList<Student>();
 89         student = new Student(4,"张三2",new Date(),null);
 90         list2.add(student);
 91         student = new Student(5,"李四2",new Date(),null);
 92         list2.add(student);
 93         student = new Student(6,"王五2",null,"山东");
 94         list2.add(student);
 95         
 96         List<Student> list3 = new ArrayList<Student>();
 97         student = new Student(7,"张三2",new Date(),null);
 98         list3.add(student);
 99         student = new Student(8,"李四2",new Date(),null);
100         list3.add(student);
101         student = new Student(9,"王五2",null,"山东");
102         list3.add(student);
103         
104         map.put("list1", list1);
105         map.put("list2", list2);
106         map.put("list3", list3);
107         
108         // map 转为 json
109         String json = JSON.toJSONString(map,SerializerFeature.WriteMapNullValue);
110         System.out.println(json);
111         
112         // json转为map
113         map = JSON.parseObject(json,new TypeReference<Map<String,List<Student>>>(){} );
114         System.out.println(map);
115     }
116 }
View Code

（2）工具类（在项目中可以直接使用）

 1 package com.fastjson.util;
 2 
 3 import java.lang.reflect.Type;
 4 import java.util.ArrayList;
 5 import java.util.Date;
 6 import java.util.List;
 7 import java.util.Map;
 8 
 9 import com.alibaba.fastjson.JSON;
10 import com.alibaba.fastjson.TypeReference;
11 import com.alibaba.fastjson.serializer.SerializerFeature;
12 import com.model.Student;
13 
14 /**
15  * @ClassName: FastJsonUtil 
16  * @Description: TODO(FastJson工具类) 
17  * @author xbq 
18  * @date 2017-2-2 下午6:25:08 
19  *
20  */
21 public class FastJsonUtil {
22 
23     /**
24      * @Title: objectToJson 
25      * @Description: TODO(实体类、List、Map转化为 json) 
26      * @param @param obj
27      * @param @return    设定文件 
28      * @return String    返回类型 
29      * @throws
30      */
31     public static String objectToJson(Object obj){
32         //  缺省情况下FastJSON不输入为值Null的字段，可以使用SerializerFeature.WriteMapNullValue使其输出
33         return JSON.toJSONString(obj, SerializerFeature.WriteMapNullValue);
34     }
35     
36     /**
37      * @Title: jsonToObject 
38      * @Description: TODO(json转化为实体) 
39      * @param @param json
40      * @param @param type
41      * @param @return    设定文件 
42      * @return Object    返回类型 
43      * @throws
44      */
45     public static Object jsonToObject(String json,Type type){
46         return JSON.parseObject(json, type);
47     }
48     
49     /**
50      * @Title: jsonToList 
51      * @Description: TODO(json转化为List) 
52      * @param @param json
53      * @param @param obj  若传 Student的时候，则  传参数  new Student()
54      * @param @return    设定文件 
55      * @return Object    返回类型 
56      * @throws
57      */
58     @SuppressWarnings("rawtypes")
59     public static  List jsonToList(String json,Object obj){
60         return JSON.parseArray(json, obj.getClass());
61     }
62     
63     /**
64      * @Title: jsonToMap 
65      * @Description: TODO(json转化为Map) 
66      * @param @param json
67      * @param @param type
68      * @param @return    设定文件 
69      * @return Object    返回类型 
70      * @throws
71      */
72     @SuppressWarnings("rawtypes")
73     public static Map jsonToMap(String json,Type type){
74         return JSON.parseObject(json,new TypeReference<Map<String,List>>(){});
75     }
76     
77     // 测试
78     public static void main(String[] args) {
79         
80         List<Student> list = new ArrayList<Student>();
81         Student student = new Student(1,"张三",new Date(),null);
82         list.add(student);
83         student = new Student(2,"李四",new Date(),null);
84         list.add(student);
85         student = new Student(3,"王五",null,"山东");
86         list.add(student);
87         
88         // list转化为 json 数组
89         String json = objectToJson(list);
90         System.out.println(json);
91         
92         // json数组转为 list
93         @SuppressWarnings("unchecked")
94         List<Student> list1 = jsonToList(json, new Student());
95         System.out.println(list1);
96     }
97 }
View Code

4.Json-lib测试类

（1）测试类

 1 package com.jsonlib.test;
 2 
 3 import java.text.SimpleDateFormat;
 4 import java.util.ArrayList;
 5 import java.util.Date;
 6 import java.util.List;
 7 
 8 import net.sf.json.JSONArray;
 9 import net.sf.json.JSONObject;
10 import net.sf.json.JsonConfig;
11 import net.sf.json.processors.JsonValueProcessor;
12 
13 import org.junit.Test;
14 
15 import com.model.Student;
16 
17 public class TestJson_lib {
18 
19     // 对象转为json
20     @Test
21     public void ObjectToJson(){
22         Student student = new Student(10,"张三",new Date(),null);
23         
24         JsonConfig config=new JsonConfig();
25         //设置 json转换的处理器用来处理日期类型
26         //凡是反序列化Date类型的对象，都会经过该处理器进行处理
27         config.registerJsonValueProcessor(Date.class, new JsonValueProcessor() {
28             //参数1 ：属性名参数2：json对象的值参数3：jsonConfig对象
29             public Object processObjectValue(String arg0, Object arg1,JsonConfig arg2) {
30                 SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
31                 Date d = (Date) arg1;
32                 return sdf.format(d);
33             }
34             public Object processArrayValue(Object arg0, JsonConfig arg1) {
35                 return null;
36             }
37         });
38         
39         JSONObject jsonObject = JSONObject.fromObject(student,config);
40         System.out.println(jsonObject.toString());
41     }
42     
43     // json转为对象   
44     @Test
45     public void JsonToObject(){
46         String json = "{"address":"","birth":"2017-02-02 16:14:42","id":10,"name":"张三"}";
47         JsonConfig config=new JsonConfig();
48         //设置 json转换的处理器用来处理日期类型
49         //凡是反序列化Date类型的对象，都会经过该处理器进行处理
50         config.registerJsonValueProcessor(Date.class, new JsonValueProcessor() {
51             //参数1 ：属性名参数2：json对象的值参数3：jsonConfig对象
52             public Object processObjectValue(String arg0, Object arg1,JsonConfig arg2) {
53                 SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
54                 Date d = (Date) arg1;
55                 return sdf.format(d);
56             }
57             public Object processArrayValue(Object arg0, JsonConfig arg1) {
58                 return null;
59             }
60         });
61         Student student = (Student) JSONObject.toBean(JSONObject.fromObject(json,config), Student.class);
62         System.out.println(student);
63     }
64     
65     @SuppressWarnings({ "deprecation", "unchecked" })
66     @Test
67     public void ListToJson(){
68         List<Student> list = new ArrayList<Student>();
69         Student student = new Student(1,"张三",new Date(),null);
70         list.add(student);
71         student = new Student(2,"李四",new Date(),null);
72         list.add(student);
73         student = new Student(3,"王五",null,"山东");
74         list.add(student);
75 
76         // list转json
77         JSONArray jsonArray = JSONArray.fromObject(list);
78         System.out.println(jsonArray);
79         
80         // json转为list
81         list = JSONArray.toList(JSONArray.fromObject(jsonArray.toString()),Student.class);
82         System.out.println(list);
83         
84         // 遍历list
85         for(Student s : list){
86             System.out.println(s);
87         }
88     }
89     
90 }
View Code

三、源码下载

源码中包含实例与jar包----- http://download.csdn.net/detail/u010821757/9746160

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原文地址：https://www.cnblogs.com/xbq8080/p/6361610.html