gson使用详解

昨天读一篇文章，看到gson这个词，一开始还以为作者写错了，问了度娘之后才发现是我才疏学浅，于是大概了解了一下gson用法，总体来说还是很简单的。

Gson.jar下载

JavaBean转json

 //javaBean-->json @Test public void test1(){ Gson gson = new Gson(); Person p = new Person("张三", "123", 500, new Book("三国演义", "罗贯中")); String json = gson.toJson(p); System.out.println(json); }
  

 

  
1
  
2
  
3
  
4
  
5
  
6
  
7
  
8
 

json转javabean

 //json-->javaBean @Test public void test2(){ String json = "{\"username\":\"张三\",\"password\":\"123\",\"money\":500,\"book\":{\"id\":0,\"name\":\"三国演义\",\"price\":0,\"author\":\"罗贯中\"}}"; Gson gson = new Gson(); Person p = gson.fromJson(json, Person.class); System.out.println(p.getUsername()+"--"+p.getBook().getName()); }
  

 

  
1
  
2
  
3
  
4
  
5
  
6
  
7
  
8
 

List集合转json

 //list-->json @Test public void test3() { List<Person> list = new ArrayList<Person>(); Person p = new Person("张三", "123", 500, new Book("三国演义", "罗贯中")); list.add(p); p = new Person("李四", "123", 500, new Book("三国演义", "罗贯中")); list.add(p); Gson gson = new Gson(); String gsonStr = gson.toJson(list); System.out.println(gsonStr); }
  

 

  
1
  
2
  
3
  
4
  
5
  
6
  
7
  
8
  
9
  
10
  
11
  
12
 

Map集合转json

 //map-->json @Test public void test4() { Map<String, Person> map = new HashMap<String, Person>(); Person p = new Person("张三", "123", 500, new Book("三国演义", "罗贯中")); map.put("p1", p); p = new Person("李四", "123", 500, new Book("三国演义", "罗贯中")); map.put("p2", p); Gson gson = new Gson(); String gsonStr = gson.toJson(map); System.out.println(gsonStr); }
  

 

  
1
  
2
  
3
  
4
  
5
  
6
  
7
  
8
  
9
  
10
  
11
  
12
 

json字符串转List集合

 //json-->list @Test public void test5() { String str = "[{\"username\":\"张三\",\"password\":\"123\",\"money\":500,\"book\":{\"id\":0,\"name\":\"三国演义\",\"price\":0,\"author\":\"罗贯中\"}},{\"username\":\"李四\",\"password\":\"123\",\"money\":500,\"book\":{\"id\":0,\"name\":\"三国演义\",\"price\":0,\"author\":\"罗贯中\"}}]"; Gson gson = new Gson(); List<Person> ps = gson.fromJson(str,new TypeToken<List<Person>>() { }.getType()); for (Person person : ps) { System.out.println(person.getUsername()+"---"+person.getBook().getName()); } }
  

 

  
1
  
2
  
3
  
4
  
5
  
6
  
7
  
8
  
9
  
10
  
11
  
12
 

json字符串转Map集合

 //json-->map @Test public void test6(){ String str = "{\"p1\":{\"username\":\"张三\",\"password\":\"123\",\"money\":500,\"book\":{\"id\":0,\"name\":\"三国演义\",\"price\":0,\"author\":\"罗贯中\"}},\"p2\":{\"username\":\"李四\",\"password\":\"123\",\"money\":500,\"book\":{\"id\":0,\"name\":\"红楼梦\",\"price\":0,\"author\":\"曹雪芹\"}}}"; Gson gson = new Gson(); Map<String, Person> map = gson.fromJson(str, new TypeToken<Map<String, Person>>(){}.getType()); Set<String> keys = map.keySet(); for(String key:keys){ System.out.println(map.get(key).getUsername()+"--"+map.get(key).getBook().getName()); } }
  

 

  
1
  
2
  
3
  
4
  
5
  
6
  
7
  
8
  
9
  
10
  
11
 

相关的两个javabean
Person.java

public class Person { private String username; private String password; private int money; private Book book; public Person() { } public Person(Book book) { this.book = book; } public Book getBook() { return book; } public void setBook(Book book) { this.book = book; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public int getMoney() { return money; } public void setMoney(int money) { this.money = money; } public Person(String username, String password, int money, Book book) { super(); this.username = username; this.password = password; this.money = money; this.book = book; }

}
  

 

  
1
  
2
  
3
  
4
  
5
  
6
  
7
  
8
  
9
  
10
  
11
  
12
  
13
  
14
  
15
  
16
  
17
  
18
  
19
  
20
  
21
  
22
  
23
  
24
  
25
  
26
  
27
  
28
  
29
  
30
  
31
  
32
  
33
  
34
  
35
  
36
  
37
  
38
  
39
  
40
  
41
  
42
  
43
  
44
  
45
  
46
  
47
  
48
 

Book.java

public class Book { private int id; private String name; private int price; private String author; private Detail detail; private Attribute attribute; public Attribute getAttribute() { return attribute; } public void setAttribute(Attribute attribute) { this.attribute = attribute; } public Detail getDetail() { return detail; } public void setDetail(Detail detail) { this.detail = detail; } 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 int getPrice() { return price; } public void setPrice(int price) { this.price = price; } public String getAuthor() { return author; } public void setAuthor(String author) { this.author = author; } public Book(String name, String author) { this.name = name; this.author = author; } public Book() { }

}
  

 

  
1
  
2
  
3
  
4
  
5
  
6
  
7
  
8
  
9
  
10
  
11
  
12
  
13
  
14
  
15
  
16
  
17
  
18
  
19
  
20
  
21
  
22
  
23
  
24
  
25
  
26
  
27
  
28
  
29
  
30
  
31
  
32
  
33
  
34
  
35
  
36
  
37
  
38
  
39
  
40
  
41
  
42
  
43
  
44
  
45
  
46
  
47
  
48
  
49
  
50
  
51
  
52
  
53
 

注意事项：
把json字符串转为集合时，new TypeToken<>(){}.getType()在eclipse中貌似不能够自动提示，如果你的电脑也是这样的话，建议这里的代码自己手动敲一下，eclipse只是不会自动提示，自己敲出来的是不会报错的，嗯，我就遇到这一个小小的问题，总体来说这个东东还是很好用的。

文章来源: wangsong.blog.csdn.net，作者：_江南一点雨，版权归原作者所有，如需转载，请联系作者。

原文链接：wangsong.blog.csdn.net/article/details/46043549