Java将对象序列化成为JSON格式、JSON格式反序列化为Java对象

摘要：Java将对象序列化成为JSON格式、JSON格式反序列化为Java对象。

一：引入jackson的依赖：

<dependency>
  <groupId>org.codehaus.jackson</groupId>
  <artifactId>jackson-mapper-asl</artifactId>
  <version>1.9.12</version>
</dependency>
<dependency>
  <groupId>org.codehaus.jackson</groupId>
  <artifactId>jackson-core-asl</artifactId>
  <version>1.9.12</version>
</dependency>

二：编写实体对象类Employee

package cn.micai.base.io;

import java.io.Serializable;

/**
 * 描述：
 * <p>
 *
 *     transient使用小结
 *     1.一旦变量被transient修饰，变量将不再是对象持久化的一部分，该变量内容在序列化后无法获得访问。
 *     2.transient关键字只能修饰变量，而不能修饰方法和类。注意，本地变量是不能被transient关键字修饰的。变量如果是用户自定义类变量，则该类需要实现Serializable接口。
 *     3.被transient关键字修饰的变量不再能被序列化，一个静态变量不管是否被transient修饰，均不能被序列化。
 *
 * @author: 赵新国
 * @date: 2018/6/7 12:10
 */
public class Employee implements Serializable {

    private static final long serialVersionUID = 1L;
    private int employeeId;
    private String employeeName;
    /**
     * 使用transient关键字，表示该字段不序列化
     */
    private transient String department;

    public int getEmployeeId() {
        return employeeId;
    }
    public void setEmployeeId(int employeeId) {
        this.employeeId = employeeId;
    }
    public String getEmployeeName() {
        return employeeName;
    }
    public void setEmployeeName(String employeeName) {
        this.employeeName = employeeName;
    }
    public String getDepartment() {
        return department;
    }
    public void setDepartment(String department) {
        this.department = department;
    }

    @Override
    public String toString() {
        return "Employee{" +
                "employeeId=" + employeeId +
                ", employeeName='" + employeeName + '\'' +
                ", department='" + department + '\'' +
                '}';
    }
}

三：编写使用jackson-all.1.7.6.jar工具包实现将对象序列化为JSON格式、JSON格式反序列化为对象的类

package cn.micai.base.io;

import org.codehaus.jackson.JsonFactory;
import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.map.ObjectMapper;

import java.io.IOException;
import java.io.StringWriter;

/**
 * @Auther: zhaoxinguo
 * @Date: 2018/8/23 12:03
 * @Description: 使用jackson-all.1.7.6.jar工具包实现将对象序列化为JSON格式、JSON格式反序列化为对象
 */
public class JacksonAllSerializeDeserializeMain {

    /**
     * 将Java对象employee序列化成为JSON格式
     * @param employee
     * @return
     */
    public static String serialize(Employee employee){
        // JSON对象序列化
        String employeeJson = null;
        try {
            ObjectMapper objectMapper = new ObjectMapper();
            StringWriter stringWriter = new StringWriter();
            JsonGenerator jsonGenerator = new JsonFactory().createJsonGenerator(stringWriter);
            objectMapper.writeValue(jsonGenerator, employee);
            jsonGenerator.close();
            employeeJson = stringWriter.toString();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return employeeJson;
    }

    /**
     * 将JSON格式反序列化为employee对象
     * @param employeeJson
     * @return
     */
    public static Employee deserialize(String employeeJson) {
        try {
            ObjectMapper objectMapper = new ObjectMapper();
            return objectMapper.readValue(employeeJson, Employee.class);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    public static void main(String [] args) {

        Employee employee = new Employee();
        employee.setEmployeeId(1);
        employee.setEmployeeName("赵新国");
        employee.setDepartment("软件工程师");
        // 序列化
        String serialize = serialize(employee);
        System.out.println(serialize);
        // 反序列化
        Employee deserialize = deserialize(serialize);
        System.out.println(deserialize);

    }

}

四：运行结果：