Json转换利器Gson之实例五-实际开发中的特殊需求处理(手动解析-TypeToken)

前面四篇博客基本上可以满足我们处理的绝大多数需求,但有时项目中对json有特殊的格式规定.比如下面的json串解析:

[{"tableName":"students","tableData":[{"id":1,"name":"李坤","birthDay":"Jun 22, 2012 9:54:49 PM"},{"id":2,"name":"曹贵生","birthDay":"Jun 22, 2012 9:54:49 PM"},{"id":3,"name":"柳波","birthDay":"Jun 22, 2012 9:54:49 PM"}]},{"tableName":"teachers","tableData":[{"id":1,"name":"米老师","title":"教授"},{"id":2,"name":"丁老师","title":"讲师"}]}]

分析之后我们发现使用前面博客中用到的都不好处理上面的json串.请看本文是如何处理的吧:

实体类:

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1. import java.util.Date;  
2.   
3. public class Student {  
4.     private int id;  
5.     private String name;  
6.     private Date birthDay;  
7.   
8.     public int getId() {  
9.         return id;  
10.     }  
11.   
12.     public void setId(int id) {  
13.         this.id = id;  
14.     }  
15.   
16.     public String getName() {  
17.         return name;  
18.     }  
19.   
20.     public void setName(String name) {  
21.         this.name = name;  
22.     }  
23.   
24.     public Date getBirthDay() {  
25.         return birthDay;  
26.     }  
27.   
28.     public void setBirthDay(Date birthDay) {  
29.         this.birthDay = birthDay;  
30.     }  
31.   
32.     @Override  
33.     public String toString() {  
34.         return "Student [birthDay=" + birthDay + ", id=" + id + ", name="  
35.                 + name + "]";  
36.     }  
37.   
38. }  

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1. public class Teacher {  
2.     private int id;  
3.   
4.     private String name;  
5.   
6.     private String title;  
7.   
8.     public int getId() {  
9.         return id;  
10.     }  
11.   
12.     public void setId(int id) {  
13.         this.id = id;  
14.     }  
15.   
16.     public String getName() {  
17.         return name;  
18.     }  
19.   
20.     public void setName(String name) {  
21.         this.name = name;  
22.     }  
23.   
24.     public String getTitle() {  
25.         return title;  
26.     }  
27.   
28.     public void setTitle(String title) {  
29.         this.title = title;  
30.     }  
31.   
32.     @Override  
33.     public String toString() {  
34.         return "Teacher [id=" + id + ", name=" + name + ", title=" + title  
35.                 + "]";  
36.     }  
37.   
38. }  

注意这里定义了一个TableData实体类:

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1. import java.util.List;  
2.   
3. public class TableData {  
4.   
5.     private String tableName;  
6.   
7.     private List tableData;  
8.   
9.     public String getTableName() {  
10.         return tableName;  
11.     }  
12.   
13.     public void setTableName(String tableName) {  
14.         this.tableName = tableName;  
15.     }  
16.   
17.     public List getTableData() {  
18.         return tableData;  
19.     }  
20.   
21.     public void setTableData(List tableData) {  
22.         this.tableData = tableData;  
23.     }  
24. }  

测试类:

(仔细看将json转回为对象的实现,这里经过两次转化,第一次转回的结果是map不是我们所期望的对象,对map再次转为json后再转为对象,我引用的是Gson2.1的jar处理正常,好像使用Gson1.6的jar会报错,所以建议用最新版本)

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1. import java.util.ArrayList;  
2. import java.util.Date;  
3. import java.util.List;  
4.   
5. import com.google.gson.Gson;  
6. import com.google.gson.reflect.TypeToken;  
7.   
8. public class GsonTest5 {  
9.   
10.     /** 
11.      * @param args 
12.      */  
13.     public static void main(String[] args) {  
14.         // 对象转为Json-->start  
15.         Student student1 = new Student();  
16.         student1.setId(1);  
17.         student1.setName("李坤");  
18.         student1.setBirthDay(new Date());  
19.   
20.         Student student2 = new Student();  
21.         student2.setId(2);  
22.         student2.setName("曹贵生");  
23.         student2.setBirthDay(new Date());  
24.   
25.         Student student3 = new Student();  
26.         student3.setId(3);  
27.         student3.setName("柳波");  
28.         student3.setBirthDay(new Date());  
29.   
30.         List<Student> stulist = new ArrayList<Student>();  
31.         stulist.add(student1);  
32.         stulist.add(student2);  
33.         stulist.add(student3);  
34.   
35.         Teacher teacher1 = new Teacher();  
36.         teacher1.setId(1);  
37.         teacher1.setName("米老师");  
38.         teacher1.setTitle("教授");  
39.   
40.         Teacher teacher2 = new Teacher();  
41.         teacher2.setId(2);  
42.         teacher2.setName("丁老师");  
43.         teacher2.setTitle("讲师");  
44.         List<Teacher> teacherList = new ArrayList<Teacher>();  
45.         teacherList.add(teacher1);  
46.         teacherList.add(teacher2);  
47.   
48.         TableData td1 = new TableData();  
49.         td1.setTableName("students");  
50.         td1.setTableData(stulist);  
51.   
52.         TableData td2 = new TableData();  
53.         td2.setTableName("teachers");  
54.         td2.setTableData(teacherList);  
55.   
56.         List<TableData> tdList = new ArrayList<TableData>();  
57.         tdList.add(td1);  
58.         tdList.add(td2);  
59.         Gson gson = new Gson();  
60.         String s = gson.toJson(tdList);  
61.   
62.         System.out.println(s);  
63.         // 结果:[{"tableName":"students","tableData":[{"id":1,"name":"李坤","birthDay":"Jun 22, 2012 10:44:16 AM"},{"id":2,"name":"曹贵生","birthDay":"Jun 22, 2012 10:44:16 AM"},{"id":3,"name":"柳波","birthDay":"Jun 22, 2012 10:44:16 AM"}]},{"tableName":"teachers","tableData":[{"id":1,"name":"米老师","title":"教授"},{"id":2,"name":"丁老师","title":"讲师"}]}]  
64.         // 对象转为Json-->end  
65.   
66.         // /////////////////////////////////////////////////////////////////////  
67.   
68.         // 将json转为数据-->start  
69.         List<TableData> tableDatas2 = gson.fromJson(s,  
70.                 new TypeToken<List<TableData>>() {  
71.                 }.getType());  
72.         for (int i = 0; i < tableDatas2.size(); i++) {  
73.             TableData entityData = tableDatas2.get(i);  
74.             String tableName = entityData.getTableName();  
75.             List tableData = entityData.getTableData();  
76.             String s2 = gson.toJson(tableData);  
77.             // System.out.println(s2);  
78.             // System.out.println(entityData.getData());  
79.             if (tableName.equals("students")) {  
80.                 System.out.println("students");  
81.                 List<Student> retStuList = gson.fromJson(s2,  
82.                         new TypeToken<List<Student>>() {  
83.                         }.getType());  
84.                 for (int j = 0; j < retStuList.size(); j++) {  
85.                     System.out.println(retStuList.get(j));  
86.                 }  
87.   
88.             } else if (tableName.equals("teachers")) {  
89.                 System.out.println("teachers");  
90.                 List<Teacher> retTchrList = gson.fromJson(s2,  
91.                         new TypeToken<List<Teacher>>() {  
92.                         }.getType());  
93.                 for (int j = 0; j < retTchrList.size(); j++) {  
94.                     System.out.println(retTchrList.get(j));  
95.                 }  
96.             }  
97.         }  
98.   
99.         // Json转为对象-->end  
100.     }  
101. }  

输出结果:

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1. [{"tableName":"students","tableData":[{"id":1,"name":"李坤","birthDay":"Jun 22, 2012 10:04:12 PM"},{"id":2,"name":"曹贵生","birthDay":"Jun 22, 2012 10:04:12 PM"},{"id":3,"name":"柳波","birthDay":"Jun 22, 2012 10:04:12 PM"}]},{"tableName":"teachers","tableData":[{"id":1,"name":"米老师","title":"教授"},{"id":2,"name":"丁老师","title":"讲师"}]}]  
2. students  
3. Student [birthDay=Fri Jun 22 22:04:12 CST 2012, id=1, name=李坤]  
4. Student [birthDay=Fri Jun 22 22:04:12 CST 2012, id=2, name=曹贵生]  
5. Student [birthDay=Fri Jun 22 22:04:12 CST 2012, id=3, name=柳波]  
6. teachers  
7. Teacher [id=1, name=米老师, title=教授]  
8. Teacher [id=2, name=丁老师, title=讲师]  
9. 
   
10. 转自：http://blog.csdn.net/lk_blog/article/category/1172246