Java 参数传递：按值传递和按地址传递

ゞ浴缸里的玫瑰 2023-10-10 17:40 39阅读 0赞

**结论：**

> 1.参数为基础类型（int，long，short等）时，本质为值传递，即对参数的任何操作都不会对原数据有影响。  
> 2.参数为对象（实例化new出来的）时，本质为引用传递，参数地址指向原数据地址，即任何操作都是在操作原数据。

**JAVA 演示功能代码:**

import com.zzg.entity.Person;
    import org.apache.hadoop.yarn.webapp.hamlet.Hamlet;
    
    public class TransferTest {
        public static void main(String[] args) {
            String str = "Hello Java 8";
            /**
             * 基本类型按值传递
             */
            System.out.println("str update before:" + str);
            updateString(str);
            System.out.println("str update after:" + str);
    
            Person person = new Person();
            person.setName("zzg");
            person.setAge(30);
            person.setHeight(2);
    
            /**
             * 对象类型：按照地址传递
             */
            System.out.println("person update before:" + person.toString());
            updatePerson(person);
            System.out.println("person update after:" + person.toString());
    
            /**
             * 对象类型：传递对象不修改原有对象通过,实现Cloneable 接口,覆写Object.clone() 方法实现。
             */
            System.out.println("clone person update before:" + person.toString());
            cloneUpdatePerson(person);
            System.out.println("clone person update after:" + person.toString());
        }
    
        public static void updateString(String str) {
            str = "Hello Python3";
        }
    
        public static void updatePerson(Person person) {
            person.setName("zzy");
            person.setAge(2);
            person.setHeight(1);
        }
    
        public static void cloneUpdatePerson(Person person) {
            Person clonePerson = null;
            try {
                clonePerson = (Person) person.clone();
            } catch (CloneNotSupportedException e) {
                System.out.println("Person clone Object is failed");
               return;
            }
            clonePerson.setName("zzy");
            clonePerson.setAge(2);
            clonePerson.setHeight(1);
    
        }
    
    }

package com.zzg.entity;
    
    import lombok.AllArgsConstructor;
    import lombok.Data;
    import lombok.NoArgsConstructor;
    
    @Data
    @AllArgsConstructor
    @NoArgsConstructor
    public class Person implements Cloneable {
        private String name;
    
        private Integer age;
    
        private Integer height;
    
        @Override
        public Object clone() throws CloneNotSupportedException {
            return super.clone();
        }
    }

运行结果:

str update before:Hello Java 8
    str update after:Hello Java 8
    person update before:Person(name=zzg, age=30, height=2)
    person update after:Person(name=zzy, age=2, height=1)
    clone person update before:Person(name=zzy, age=2, height=1)
    clone person update after:Person(name=zzy, age=2, height=1)