java001-泛型
泛型出现的意义:
为编码阶段的不确定性和转化做视觉设计
将运行期遇到的问题转移到编译期,省去了强转的麻烦
package com.xiaolin.basic; /** * 泛型:将运行期遇到的问题转移到了编译期,省去了强转的麻烦 * val1,val2 * @author: xiaolin * @Date: 2021/6/11 22:49 * @Description: */ public class LocalPair<K,V> { private K k; private V v; public LocalPair(K k, V v) { this.k = k; this.v = v; } public K getK() { return k; } public V getV() { return v; } }
package com.xiaolin.basic; import java.util.Date; public class LocalPairApp { public static void main(String[] args) { LocalPair<String,String> pair = foo1(); String k = pair.getK(); String v = pair.getV(); String[] arrs = k.split(","); String[] arrs2 = v.split(","); for (String s:arrs){ System.out.println(s); } for (String b:arrs2){ System.out.println(b); } } public static LocalPair<String,String> foo1(){ LocalPair<String,String> pair1 = new LocalPair<>("abc,rer","bcd,oiu"); return pair1; } public static LocalPair<String,Integer> foo2(){ LocalPair<String,Integer> pair2 = new LocalPair<>("bdsd",123); return pair2; } public static LocalPair<String, Date> foo3(){ LocalPair<String,Date> pair3 = new LocalPair<>("bdsd",new Date()); return pair3; } }