Set HashSet

public static void main(String[] args) {

??//不可以重復(fù)? 并且是無序的
??//自然排序? 從A-Z
??//eqauls從Object繼承，默認(rèn)比較地址
//??Set<String> set= new HashSet<>();
//??set.add("zs");
//??set.add("ls");
//??set.add("ww");
//??set.add("qq");
//??set.add("zs");
//??System.out.println(set.size());
//??//遍歷
??//迭代器
//??Iterator<String > it= set.iterator();
//??while(it.hasNext()) {
//???System.out.println(it.next());
//??}
//??System.out.println("-------------------");
//??//Foreach
//??for(String s: set) {
//???System.out.println(s);
//??}
??
??//常用實現(xiàn)類? HashSet
??Set<Person> s= new HashSet<>();
???//System.out.println(new Person(1,"ls",18).equals(new Person(1,"zs",18)));
???//System.out.println(new Person(1,"zs",18));
??s.add(new Person(1,"zs",18));
??s.add(new Person(2,"ls",18));
??s.add(new Person(3,"ww",18));
??s.add(new Person(4,"zl",18));
??s.add(new Person(5,"qq",18));
??
??//foreach的底層原理就是迭代器
??for(Person p:s) {
???//默認(rèn)轉(zhuǎn)換為String的數(shù)據(jù)類型
???System.out.println(p);
??}
??
?}

?

?

TreeSet

public static void main(String[] args) {

//常用實現(xiàn)類? TreeSet ：根據(jù)某種（規(guī)則）對里面的元素進行排序
???????????????? //規(guī)則1 ：java.lang.Comparable
???????????????? //規(guī)則2 ：java.util.Comparator
//??Set<String> set= new TreeSet<>();
//??set.add("zs");
//??set.add("ls");
//??set.add("ww");
//??set.add("qq");
//??set.add("zs");
//??System.out.println(set.size());
//??

遍歷

迭代器
//??Iterator<String > it= set.iterator();
//??while(it.hasNext()) {
//???System.out.println(it.next());
//??}
//??System.out.println("-------------------");
//? Foreach
//??for(String s: set) {
//???System.out.println(s);
//??}
??
??//自然排序器
??
//??Set<Person> s= new TreeSet<>();
// ??//System.out.println(new Person(1,"ls",18).equals(new Person(1,"zs",18)));
// ??//System.out.println(new Person(1,"zs",18));
//??s.add(new Person(1,"zs",18));
//??s.add(new Person(2,"ls",18));
//??s.add(new Person(3,"ww",18));
//??s.add(new Person(4,"zl",18));
//??s.add(new Person(5,"qq",18));
//??
//??//foreach的底層原理就是迭代器
//??for(Person p:s) {
//???//默認(rèn)轉(zhuǎn)換為String的數(shù)據(jù)類型
//???System.out.println(p);
//??}
??
??// 自定義的排序器(根據(jù)年齡排序)
??Set<Person> s= new TreeSet<>(new Age());
???//System.out.println(new Person(1,"ls",18).equals(new Person(1,"zs",18)));
???//System.out.println(new Person(1,"zs",18));
??s.add(new Person(1,"zs",18));
??s.add(new Person(2,"ls",19));
??s.add(new Person(3,"ww",80));
??s.add(new Person(4,"zl",30));
??s.add(new Person(5,"qq",20));

??for(Person p:s) {
???System.out.println(p);
??}
??
?}

?

轉(zhuǎn)載于:https://www.cnblogs.com/ly-0919/p/10904520.html

總結(jié)

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