📜  Jackson-对象序列化

📅  最后修改于: 2020-11-16 07:31:52             🧑  作者: Mango


让我们将一个Java对象序列化为一个json文件,然后读取该json文件以将该对象取回。在此示例中,我们创建了Student类。我们将创建一个student.json文件,该文件将具有Student对象的json表示形式。

C:\> Jackson_WORKSPACE中创建一个名为JacksonTester的Java类文件。

文件:JacksonTester.java

import java.io.File;
import java.io.IOException;

import com.fasterxml.jackson.core.JsonGenerationException;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonTester {
   public static void main(String args[]){
      JacksonTester tester = new JacksonTester();
      try {
         Student student = new Student();
         student.setAge(10);
         student.setName("Mahesh");
         tester.writeJSON(student);

         Student student1 = tester.readJSON();
         System.out.println(student1);

      } catch (JsonParseException e) {
         e.printStackTrace();
      } catch (JsonMappingException e) {
         e.printStackTrace();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }

   private void writeJSON(Student student) throws JsonGenerationException, JsonMappingException, IOException{
      ObjectMapper mapper = new ObjectMapper();    
      mapper.writeValue(new File("student.json"), student);
   }

   private Student readJSON() throws JsonParseException, JsonMappingException, IOException{
      ObjectMapper mapper = new ObjectMapper();
      Student student = mapper.readValue(new File("student.json"), Student.class);
      return student;
   }
}

class Student {
   private String name;
   private int age;
   public Student(){}
   public String getName() {
      return name;
   }
   public void setName(String name) {
      this.name = name;
   }
   public int getAge() {
      return age;
   }
   public void setAge(int age) {
      this.age = age;
   }
   public String toString(){
      return "Student [ name: "+name+", age: "+ age+ " ]";
   }    
}

验证结果

使用javac编译器编译类,如下所示:

C:\Jackson_WORKSPACE>javac JacksonTester.java

现在运行jacksonTester以查看结果:

C:\Jackson_WORKSPACE>java JacksonTester

验证输出

Student [ name: Mahesh, age: 10 ]