JavaSE-Object类

Object类

总结

（1）对于字符串（变量）来说，==和equals是比较字符串中所包含的内容

（2）对于非字符串（引用型变量）来说，==和equals都是比较两个对象在堆内存中的首地址

（3）对于new String()来说，==是比较两个对象在内存中的首地址；对于StringBuffer来说，equals也是比较两个对象在内存中的首地址

• toString方法

package com.Object.util;
/*
 * @author Administrator
 * @version 1.0
 */
public class ObjectDemo {
	//成员变量
	private String name;
	private int age;
	
	//构造函数
	public ObjectDemo(String name, int age) {
		this.name = name;
		this.age = age;
	}

	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;
	}
	//重写toString()方法
	public String afterToString() {
		return this.name;
	}
}

• equals()方法

• package com.Object.util;
  /*
   * @author Administrator
   * @version 1.0
   */
  public class Person {
  	//成员变量
  	private String name;
  	private String number;
  	//构造函数
  	public Person(String name, String number) {
  		this.name = name;
  		this.number = number;
  	}
  	public String getName() {
  		return name;
  	}
  	public void setName(String name) {
  		this.name = name;
  	}
  	public String getNumber() {
  		return number;
  	}
  	public void setNumber(String number) {
  		this.number = number;
  	}
  	//重写equals()方法
  	public Boolean afterEquals(Object obj) {
  		if(this == obj) {
  			return true;
  		}
  		
  		if(obj instanceof Person) {
  			Person person = (Person) obj;
  			if(this.name == person.name && this.number == person.number) {
  				return true;
  			}
  		}else {
  			System.out.println(obj.getClass());
  		}
  		return false;
  	}
  }
  

  package com.Object.util;
  /*
   * @author Administrator
   * @version 1.0
   */
  public class Teacher {
  	//成员变量
  	private String name;
  	private String number;
  	//构造函数
  	public Teacher(String name, String number) {
  		this.name = name;
  		this.number = number;
  	}
  	public String getName() {
  		return name;
  	}
  	public void setName(String name) {
  		this.name = name;
  	}
  	public String getNumber() {
  		return number;
  	}
  	public void setNumber(String number) {
  		this.number = number;
  	}
  }
  

• toString()和equals()方法的重写前后的实现

• package com.Object.util;
  /*
   * @author Administrator
   * @version 1.0
   */
  public class ObjectTest {
  	
  	public static void main(String[] args) {
  		//Object类的toString()方法
  		ObjectDemo od = new ObjectDemo("Administrator", 24);
  		//重写之前的toString()方法
  		System.out.println(od.toString());  		//com.Object.util.ObjectDemo@70dea4e
  		//重写之后的toString()方法
  		System.out.println(od.afterToString());  		//Administrator
  		//Object类的equals()方法
  		Person person1 = new Person("人","123");
  		Person person2 = new Person("人","123");
  		Teacher teacher = new Teacher("人","123");
  		//重写之前的equals()方法
  		System.out.println(person1.equals(person2));  //false
  		//重写之后的equals()方法
  		System.out.println(person1.afterEquals(person2)); 
  		//true
  		System.out.println(person1.afterEquals(teacher));
  		//class com.Object.util.Teacher
  		//false
  	}
  }