JCF框架hashset中hashcode()和equals()的用法

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package quickstart;import java.util.HashSet;import java.util.Iterator;/** * Created by patkritLee on 2017/2/28. */public class HelloWorld {    public static void main(String[] args) {        HashSet has = new HashSet();        has.add(new Person("a1",11));        has.add(new Person("a2",12));        has.add(new Person("a3",13));        has.add(new Person("a4",14));        System.out.println("a1:"+ has.contains(new Person("a1",11)));        Iterator it = has.iterator();        while(it.hasNext()){            Person p = (Person)it.next();            System.out.println(p.getName()+"::"+p.getAge());        }    }}class Person{    private String name;    private int age;    Person(String name,int age){        this.name = name;        this.age = age;    }    void SetName(String name){        this.name = name;    }    void SetAge(int age){        this.age = age;    }    String getName(){        return name;    }    int getAge(){        return age;    }    public int hashCode(){        System.out.println(this.name+"...hashCode");        return name.hashCode()+age*37;    }    public boolean equals(Object obj) {        if (!(obj instanceof Person))            return false;        Person p = (Person) obj;        System.out.println(this.name + "...equals..." + p.name);        return this.name.equals(p.name) && this.age == p.age;    }}

运行结果：

"C:\Program Files\Java\jdk1.8.0_111\bin\java" -Didea.launcher.port=7533 "-Didea.launcher.bin.path=C:\Program Files (x86)\JetBrains\IntelliJ IDEA Community Edition 2016.3.1\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_111\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\rt.jar;E:\java\workspace\HelloWorld\out\production\HelloWorld;C:\Program Files (x86)\JetBrains\IntelliJ IDEA Community Edition 2016.3.1\lib\idea_rt.jar" com.intellij.rt.execution.application.AppMain quickstart.HelloWorlda1...hashCodea2...hashCodea3...hashCodea4...hashCodea1...hashCodea1...equals...a1a1:truea3::13a1::11a4::14a2::12Process finished with exit code 0

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