Gson 是 Google 提供的用來在 Java 對象和 JSON 數據之間進行映射的 Java 類庫。可以將一個 JSON 字符串轉成一個 Java 對象,或者反過來。
jar和源碼下載地址: http://code.google.com/p/google-gson/downloads/list
實體類:
- public class Student {
- private int id;
- private String name;
- 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 + "]";
- }
- }
測試類:
- import java.util.ArrayList;
- import java.util.Date;
- import java.util.List;
- import com.google.gson.Gson;
- import com.google.gson.reflect.TypeToken;
- public class GsonTest1 {
- public static void main(String[] args) {
- Gson gson = new Gson();
- Student student1 = new Student();
- student1.setId(1);
- student1.setName("李坤");
- student1.setBirthDay(new Date());
- // //////////////////////////////////////////////////////////
- System.out.println("----------簡單對象之間的轉化-------------");
- // 簡單的bean轉爲json
- String s1 = gson.toJson(student1);
- System.out.println("簡單Bean轉化爲Json===" + s1);
- // json轉爲簡單Bean
- Student student = gson.fromJson(s1, Student.class);
- System.out.println("Json轉爲簡單Bean===" + student);
- // 結果:
- // 簡單Bean轉化爲Json==={"id":1,"name":"李坤","birthDay":"Jun 22, 2012 8:27:52 AM"}
- // Json轉爲簡單Bean===Student [birthDay=Fri Jun 22 08:27:52 CST 2012, id=1,
- // name=李坤]
- // //////////////////////////////////////////////////////////
- Student student2 = new Student();
- student2.setId(2);
- student2.setName("曹貴生");
- 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("----------帶泛型的List之間的轉化-------------");
- // 帶泛型的list轉化爲json
- String s2 = gson.toJson(list);
- System.out.println("帶泛型的list轉化爲json==" + s2);
- // json轉爲帶泛型的list
- List<Student> retList = gson.fromJson(s2,
- new TypeToken<List<Student>>() {
- }.getType());
- for (Student stu : retList) {
- System.out.println(stu);
- }
- // 結果:
- // 帶泛型的list轉化爲json==[{"id":1,"name":"李坤","birthDay":"Jun 22, 2012 8:28:52 AM"},{"id":2,"name":"曹貴生","birthDay":"Jun 22, 2012 8:28:52 AM"},{"id":3,"name":"柳波","birthDay":"Jun 22, 2012 8:28:52 AM"}]
- // Student [birthDay=Fri Jun 22 08:28:52 CST 2012, id=1, name=李坤]
- // Student [birthDay=Fri Jun 22 08:28:52 CST 2012, id=2, name=曹貴生]
- // Student [birthDay=Fri Jun 22 08:28:52 CST 2012, id=3, name=柳波]
- }
- }
執行結果:
- ----------簡單對象之間的轉化-------------
- 簡單Bean轉化爲Json==={"id":1,"name":"李坤","birthDay":"Jun 22, 2012 9:10:31 PM"}
- Json轉爲簡單Bean===Student [birthDay=Fri Jun 22 21:10:31 CST 2012, id=1, name=李坤]
- ----------帶泛型的List之間的轉化-------------
- 帶泛型的list轉化爲json==[{"id":1,"name":"李坤","birthDay":"Jun 22, 2012 9:10:31 PM"},{"id":2,"name":"曹貴生","birthDay":"Jun 22, 2012 9:10:31 PM"},{"id":3,"name":"柳波","birthDay":"Jun 22, 2012 9:10:31 PM"}]
- Student [birthDay=Fri Jun 22 21:10:31 CST 2012, id=1, name=李坤]
- Student [birthDay=Fri Jun 22 21:10:31 CST 2012, id=2, name=曹貴生]
- Student [birthDay=Fri Jun 22 21:10:31 CST 2012, id=3, name=柳波]