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:
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import java.util.Date;
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import com.google.gson.annotations.Expose;
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import com.google.gson.annotations.SerializedName;
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public class Student {
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private int id;
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@Expose
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private String name;
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@Expose
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@SerializedName("bir")
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private Date birthDay;
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public int getId() {
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return id;
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}
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public void setId(int id) {
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this.id = id;
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}
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public String getName() {
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return name;
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}
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public void setName(String name) {
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this.name = name;
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}
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public Date getBirthDay() {
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return birthDay;
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}
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public void setBirthDay(Date birthDay) {
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this.birthDay = birthDay;
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}
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@Override
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public String toString() {
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return "Student [birthDay=" + birthDay + ", id=" + id + ", name="
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+ name + "]";
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}
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}
测试类:
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import java.util.ArrayList;
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import java.util.Date;
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import java.util.List;
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import com.google.gson.FieldNamingPolicy;
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import com.google.gson.Gson;
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import com.google.gson.GsonBuilder;
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import com.google.gson.reflect.TypeToken;
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public class GsonTest2 {
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public static void main(String[] args) {
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Gson gson = new GsonBuilder()
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.excludeFieldsWithoutExposeAnnotation()
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.enableComplexMapKeySerialization()
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.serializeNulls().setDateFormat("yyyy-MM-dd HH:mm:ss:SSS")
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.setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE)
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.setPrettyPrinting()
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.setVersion(1.0)
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.create();
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Student student1 = new Student();
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student1.setId(1);
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student1.setName("李坤");
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student1.setBirthDay(new Date());
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System.out.println("----------简单对象之间的转化-------------");
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String s1 = gson.toJson(student1);
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System.out.println("简单Bean转化为Json===" + s1);
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Student student = gson.fromJson(s1, Student.class);
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System.out.println("Json转为简单Bean===" + student);
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Student student2 = new Student();
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student2.setId(2);
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student2.setName("曹贵生");
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student2.setBirthDay(new Date());
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Student student3 = new Student();
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student3.setId(3);
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student3.setName("柳波");
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student3.setBirthDay(new Date());
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List<Student> list = new ArrayList<Student>();
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list.add(student1);
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list.add(student2);
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list.add(student3);
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System.out.println("----------带泛型的List之间的转化-------------");
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String s2 = gson.toJson(list);
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System.out.println("带泛型的list转化为json==" + s2);
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List<Student> retList = gson.fromJson(s2,
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new TypeToken<List<Student>>() {
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}.getType());
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for (Student stu : retList) {
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System.out.println(stu);
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}
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}
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}
输出结果:
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----------简单对象之间的转化-------------
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简单Bean转化为Json==={
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"Name": "李坤",
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"bir": "2012-06-22 21:26:40:592"
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}
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Json转为简单Bean===Student [birthDay=Fri Jun 22 21:26:40 CST 2012, id=0, name=李坤]
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----------带泛型的List之间的转化-------------
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带泛型的list转化为json==[
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{
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"Name": "李坤",
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"bir": "2012-06-22 21:26:40:592"
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},
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{
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"Name": "曹贵生",
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"bir": "2012-06-22 21:26:40:625"
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},
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{
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"Name": "柳波",
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"bir": "2012-06-22 21:26:40:625"
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}
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]
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Student [birthDay=Fri Jun 22 21:26:40 CST 2012, id=0, name=李坤]
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Student [birthDay=Fri Jun 22 21:26:40 CST 2012, id=0, name=曹贵生]
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Student [birthDay=Fri Jun 22 21:26:40 CST 2012, id=0, name=柳波]
Json转换利器Gson之实例一-简单对象转化和带泛型的List转化 (http://blog.csdn.net/lk_blog/article/details/7685169)
Json转换利器Gson之实例二-Gson注解和GsonBuilder (http://blog.csdn.net/lk_blog/article/details/7685190)
Json转换利器Gson之实例三-Map处理(上) (http://blog.csdn.net/lk_blog/article/details/7685210)
Json转换利器Gson之实例四-Map处理(下) (http://blog.csdn.net/lk_blog/article/details/7685224)
Json转换利器Gson之实例五-实际开发中的特殊需求处理 (http://blog.csdn.net/lk_blog/article/details/7685237)
Json转换利器Gson之实例六-注册TypeAdapter及处理Enum类型 (http://blog.csdn.net/lk_blog/article/details/7685347)
实例代码下载: http://download.csdn.net/detail/lk_blog/4387822
Json转换利器Gson之实例二-Gson注解和GsonBuilder
原文：http://blog.csdn.net/zhangming1013/article/details/44960951
