Java面向对象-Object类

Object类是所有类的父类

Object类的常用方法

1.public String toString() 返回该对象的字符串表示

2.public boolean equals(Object obj) 指示其他某个对象是否与此对象“相等”

先讲toString()方法：

public class Person {
	private String name;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Person(String name) {
		super();
		this.name = name;
	}
	public static void main(String[] args) {
		Person p=new Person("小明");
		System.out.println(p);
		System.out.println(p.toString());
	}
}
           

运行结果

输出对象，默认调用的是toString()方法

这里我们通过修改toString()实现，来实现输出对象的结果

public class Person {
	private String name;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Person(String name) {
		super();
		this.name = name;
	}
	
	
	@Override
	public String toString() {
		return this.getName();
	}

	public static void main(String[] args) {
		Person p=new Person("小明");
		System.out.println(p);
		System.out.println(p.toString());
	}
}
           

运行结果

最后说下equals 是比较对象的引用，是否指向同一个堆内存（跟字符串的equals区别开）

public class Person {
	private String name;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Person(String name) {
		super();
		this.name = name;
	}

	public static void main(String[] args) {
		Person p=new Person("小明");
		Person p1=new Person("小明");
		System.out.println(p.equals(p1));
	}
}
           

运行结果

我们来重写下equals方法，来实现比较具体内容

public class Person {
	private String name;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Person(String name) {
		super();
		this.name = name;
	}

	@Override
	public boolean equals(Object obj) {
		String name=((Person)obj).getName();
		return this.name==name;
	}

	public static void main(String[] args) {
		Person p=new Person("小明");
		Person p1=new Person("小明");
		Person p2=new Person("小红");
		System.out.println(p.equals(p1));
		System.out.println(p.equals(p2));
	}
}
           

运行结果