java程序语言Set集合方法演示
import java.util.Collection;import java.util.Comparator;import java.util.HashSet;import java.util.Iterator;import java.util.Set;public class HashSetDemos {public static void main(String[] args) {// 新建一个Set类的集合Set st = new HashSet();st.add("abc1");st.add("abc2");st.add("abc1");st.add("abc2");//输出结果只会有 abc1 和abc2 不允许元素重复Iterator it = st.iterator();while(it.hasNext()){System.out.println(it.next());}st.removeAll(st);st.add(new Studenti("lisi",23));st.add(new Studenti("lisi",24));st.add(new Studenti("lisan",22));st.add(new Studenti("lisan",20));Iterator its = st.iterator();while(its.hasNext()){Studenti s = (Studenti) its.next();System.out.println(s.getName()+" "+s.getAge());}}}class Studenti{private String name;private int age;Studenti(String name ,int age){this.name=name;this.age = age;}public int getAge(){return age;}public String getName(){return name;}public String toString(){return "the student name : +name "+" and age is : "+ age;}public int hashCode(){return name.hashCode()+age*10;}public boolean equals(Object obj){ if(this == obj)return true ;//同一个对象放两次，，直接返回trueif(!(obj instanceof Studenti))throw new ClassCastException("类型错误");Studenti p = (Studenti)obj;return this .name.equals(p.name) && this.age == p.age;}}
运行程序：
没有什么可留恋，只有抑制不住的梦想，没有什么可凭仗，
