publicclassTest{publicstaticvoid main(String args []){User u1 =newUser();User u2 =newUser();User u3 = u1; boolean b1 = u1 == u2; boolean b2 = u1 == u3;System.out.println(b1);System.out.println(b2);}}classUser{String name;int age;public boolean equals(Object obj){if(this== obj){returntrue;}//instanceof作用：判断前面的对象是不是后面对象的类型 boolean b = obj instanceof User;if(b){//obj向下转型为User对象User u =(User)obj;if(this.age == u.age &&this.name.equals(u.name)){returntrue;}else{returnfalse;}}else{returnfalse;}}}publicclassTest{publicstaticvoid main(String args []){User u1 =newUser();User u2 =newUser();User u3 =newUser(); u1.name ="zhagnsan"; u1.age =12; u2.name ="lisi"; u2.age =12; u3.name ="zhagnsan"; u3.age =12;System.out.println(u1.equals(u2));System.out.println(u1.equals(u3));}}原文：http://www.cnblogs.com/arroneve/p/5815474.html