Jackson-对象序列化

本文讲解如何将一个Java对象序列化为一个json文件，然后读取该json文件读取回对象。在下面的示例中，我们创建Student类。使用Jackson存储到一个student.json文件，该文件拥有Student对象的JSON表示形式。

1 编写核心类

MainApp：

package cn.xnip.jackson;

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

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

/**
 * 小牛知识库网 - https://www.xnip.cn
 */
public class MainApp {

    public static void main(String args[]){
        MainApp tester = new MainApp();
        try {
            Student student = new Student();
            student.setAge(10);
            student.setName("eric");
            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+ " ]";
    }
}

2 运行测试