Json转换利器Gson之实例二-Gson注解和GsonBuilder
来源:互联网 发布:暴走鞋淘宝网 编辑:程序博客网 时间:2024/05/19 02:02
有时候我们不需要把实体的所有属性都导出,只想把一部分属性导出为Json.
有时候我们的实体类会随着版本的升级而修改.
有时候我们想对输出的json默认排好格式.
... ...
请看下面的例子吧:
实体类:
- import java.util.Date;
-
- import com.google.gson.annotations.Expose;
- import com.google.gson.annotations.SerializedName;
-
- public class Student {
- private int id;
-
- @Expose
- private String name;
-
- @Expose
- @SerializedName("bir")
- private Date birthDay;
-
- 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 Date getBirthDay() {
- return birthDay;
- }
-
- public void setBirthDay(Date birthDay) {
- this.birthDay = birthDay;
- }
-
- @Override
- public String toString() {
- return "Student [birthDay=" + birthDay + ", id=" + id + ", name="
- + name + "]";
- }
-
- }
测试类:
- import java.util.ArrayList;
- import java.util.Date;
- import java.util.List;
-
- import com.google.gson.FieldNamingPolicy;
- import com.google.gson.Gson;
- import com.google.gson.GsonBuilder;
- import com.google.gson.reflect.TypeToken;
-
- public class GsonTest2 {
-
- public static void main(String[] args) {
-
- Gson gson = new GsonBuilder()
- .excludeFieldsWithoutExposeAnnotation()
- .enableComplexMapKeySerialization()
- .serializeNulls().setDateFormat("yyyy-MM-dd HH:mm:ss:SSS")
- .setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE)
-
- .setPrettyPrinting()
- .setVersion(1.0)
-
-
-
- .create();
-
-
-
- Student student1 = new Student();
- student1.setId(1);
- student1.setName("李坤");
- student1.setBirthDay(new Date());
-
-
- System.out.println("----------简单对象之间的转化-------------");
-
- String s1 = gson.toJson(student1);
- System.out.println("简单Bean转化为Json===" + s1);
-
-
- Student student = gson.fromJson(s1, Student.class);
- System.out.println("Json转为简单Bean===" + student);
-
-
- Student student2 = new Student();
- student2.setId(2);
- student2.setName("曹贵生");
- student2.setBirthDay(new Date());
-
- Student student3 = new Student();
- student3.setId(3);
- student3.setName("柳波");
- student3.setBirthDay(new Date());
-
- List<Student> list = new ArrayList<Student>();
- list.add(student1);
- list.add(student2);
- list.add(student3);
-
- System.out.println("----------带泛型的List之间的转化-------------");
-
- String s2 = gson.toJson(list);
- System.out.println("带泛型的list转化为json==" + s2);
-
-
- List<Student> retList = gson.fromJson(s2,
- new TypeToken<List<Student>>() {
- }.getType());
- for (Student stu : retList) {
- System.out.println(stu);
- }
-
- }
- }
输出结果:
- ----------简单对象之间的转化-------------
- 简单Bean转化为Json==={
- "Name": "李坤",
- "bir": "2012-06-22 21:26:40:592"
- }
- Json转为简单Bean===Student [birthDay=Fri Jun 22 21:26:40 CST 2012, id=0, name=李坤]
- ----------带泛型的List之间的转化-------------
- 带泛型的list转化为json==[
- {
- "Name": "李坤",
- "bir": "2012-06-22 21:26:40:592"
- },
- {
- "Name": "曹贵生",
- "bir": "2012-06-22 21:26:40:625"
- },
- {
- "Name": "柳波",
- "bir": "2012-06-22 21:26:40:625"
- }
- ]
- Student [birthDay=Fri Jun 22 21:26:40 CST 2012, id=0, name=李坤]
- Student [birthDay=Fri Jun 22 21:26:40 CST 2012, id=0, name=曹贵生]
- Student [birthDay=Fri Jun 22 21:26:40 CST 2012, id=0, name=柳波]