Gson 简明教程

Gson - Serializing Inner Classes

在本章中，我们将讲解包含内部类的类的序列化/反序列化。

Nested Inner Class example

Student student = new Student();
student.setRollNo(1);
Student.Name name = student.new Name();
name.firstName = "Mahesh";
name.lastName = "Kumar";

student.setName(name);
//serialize inner class object
String nameString = gson.toJson(name);
System.out.println(nameString);

//deserialize inner class object
name = gson.fromJson(nameString,Student.Name.class);
System.out.println(name.getClass());

Example

让我们看一个序列化/反序列化带有内部类的类的示例。在 C:\>GSON_WORKSPACE 中创建一个名为 GsonTester 的 Java 类文件。

File − GsonTester.java

import com.google.gson.Gson;

public class GsonTester {
   public static void main(String args[]) {

      Student student = new Student();
      student.setRollNo(1);
      Student.Name name = student.new Name();

      name.firstName = "Mahesh";
      name.lastName = "Kumar";
      student.setName(name);
      Gson gson = new Gson();

      String jsonString = gson.toJson(student);
      System.out.println(jsonString);
      student = gson.fromJson(jsonString, Student.class);

      System.out.println("Roll No: "+ student.getRollNo());
      System.out.println("First Name: "+ student.getName().firstName);
      System.out.println("Last Name: "+ student.getName().lastName);

      String nameString = gson.toJson(name);
      System.out.println(nameString);

      name = gson.fromJson(nameString,Student.Name.class);
      System.out.println(name.getClass());
      System.out.println("First Name: "+ name.firstName);
      System.out.println("Last Name: "+ name.lastName);
   }
}

class Student {
   private int rollNo;
   private Name name;

   public int getRollNo() {
      return rollNo;
   }

   public void setRollNo(int rollNo) {
      this.rollNo = rollNo;
   }

   public Name getName() {
      return name;
   }

   public void setName(Name name) {
      this.name = name;
   }

   class Name {
      public String firstName;
      public String lastName;
   }
}

Verify the result

使用以下 javac 编译器编译类：

C:\GSON_WORKSPACE>javac GsonTester.java

现在运行 GsonTester 来查看结果 −

C:\GSON_WORKSPACE>java GsonTester

验证输出。

{"rollNo":1,"name":{"firstName":"Mahesh","lastName":"Kumar"}}
Roll No: 1
First Name: Mahesh
Last Name: Kumar

{"firstName":"Mahesh","lastName":"Kumar"}
class Student$Name
First Name: Mahesh
Last Name: Kumar

Nested Static Inner Class Example

Student student = new Student();
student.setRollNo(1);
Student.Name name = new Student.Name();

name.firstName = "Mahesh";
name.lastName = "Kumar";
student.setName(name);

//serialize static inner class object
String nameString = gson.toJson(name);
System.out.println(nameString);

//deserialize static inner class object
name = gson.fromJson(nameString,Student.Name.class);
System.out.println(name.getClass());

Example

让我们看一个序列化/反序列化带有静态内部类的类的示例。在 C:\>GSON_WORKSPACE 中创建一个名为 GsonTester 的 Java 类文件。

File − GsonTester.java

import com.google.gson.Gson;

public class GsonTester {
   public static void main(String args[]) {

      Student student = new Student();
      student.setRollNo(1);
      Student.Name name = new Student.Name();

      name.firstName = "Mahesh";
      name.lastName = "Kumar";
      student.setName(name);

      Gson gson = new Gson();
      String jsonString = gson.toJson(student);
      System.out.println(jsonString);
      student = gson.fromJson(jsonString, Student.class);

      System.out.println("Roll No: "+ student.getRollNo());
      System.out.println("First Name: "+ student.getName().firstName);
      System.out.println("Last Name: "+ student.getName().lastName);
      String nameString = gson.toJson(name);
      System.out.println(nameString);

      name = gson.fromJson(nameString,Student.Name.class);
      System.out.println(name.getClass());
      System.out.println("First Name: "+ name.firstName);
      System.out.println("Last Name: "+ name.lastName);
   }
}

class Student {
   private int rollNo;
   private Name name;

   public int getRollNo() {
      return rollNo;
   }

   public void setRollNo(int rollNo) {
      this.rollNo = rollNo;
   }

   public Name getName() {
      return name;
   }

   public void setName(Name name) {
      this.name = name;
   }

   static class Name {
      public String firstName;
      public String lastName;
   }
}

Verify the result

使用以下 javac 编译器编译类：

C:\GSON_WORKSPACE>javac GsonTester.java

现在运行 GsonTester 以查看结果 −

C:\GSON_WORKSPACE>java GsonTester

验证输出。

{"rollNo":1,"name":{"firstName":"Mahesh","lastName":"Kumar"}}
Roll No: 1
First Name: Mahesh
Last Name: Kumar

{"firstName":"Mahesh","lastName":"Kumar"}
class Student$Name
First Name: Mahesh
Last Name: Kumar