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equals与hashCode在实际开发中的重写写法

 
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package com.tarena.corejava.day10;
/**
 * 该类展示equals/hashCode两个方法的实际开发中的标准写法
 * @author Administrator
 *
 */
public class TestEqualsHashCode {
    private int id;
    private String name;
    
    
	public TestEqualsHashCode(int id, String name) {
		super();
		this.id = id;
		this.name = name;
	}

	@Override
	public boolean equals(Object obj) {
		if(obj == null) return false;
		if(this.getClass()==obj.getClass()){//利用反射取确切的类型
			TestEqualsHashCode tec = (TestEqualsHashCode)obj;
			return tec.id == this.id;//比较基本数据类型用==
			//return tec.name.equals(this.name);//比较引用类型用equals
		}
		return false;
	}

	@Override
	public int hashCode() {
		int type = this.getClass().hashCode();
		int code = type*31+id;
		System.out.println("Hash码"+code);
		return code;
		//return type*31 +name.hashCode();//返回引用类型的hashCode的方法,引用.hashCode
	}
	
	public static void main(String[] args) {
		TestEqualsHashCode tec1 = new TestEqualsHashCode(1,"alpha");
		TestEqualsHashCode tec2 = new TestEqualsHashCode(2,"jack");
		TestEqualsHashCode tec3 = new TestEqualsHashCode(1,"alpha");
		System.out.println(tec1.equals(tec2));
		System.out.println(tec1.equals(tec3));
		
		if(tec1.hashCode() == tec2.hashCode()){
			System.out.println("hashCode相同");
		  }else{
			  System.out.println("hashCode不相同");  
		  }	
	}
	
}

 

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