心得总结一

枚举类:

package com.aliyun.sop.myEnum;import java.util.HashMap;
import java.util.Map;public enum MyProductEnum {APPLE(001,"苹果","apple"),ORANGE(002,"橘子","orange"),BANANA(003,"香蕉","banana");private Integer code;private String name;private String enName;private static final Map map = new HashMap<>();static {for (MyProductEnum product :MyProductEnum.values()){map.put(product.getCode(),product);}}private MyProductEnum(Integer code, String name, String enName) {this.code = code;this.name = name;this.enName = enName;}public static MyProductEnum getEnum(Integer code){return map.get(code);}public void setCode(Integer code) {this.code = code;}public void setName(String name) {this.name = name;}public void setEnName(String enName) {this.enName = enName;}public Integer getCode() {return code;}public String getName() {return name;}public String getEnName() {return enName;}
}

遍历集合并把符合条件的从集合里删除。

    @Testpublic void testListRemove(){List<Integer> list = new ArrayList<>();list.add(3);list.add(10);list.add(5);list.add(4);list.add(15);Iterator<Integer> it = list.iterator();//使用迭代器，同时移除时使用it.remove();while(it.hasNext()){Integer next = it.next();if(next % 5 == 0){/* ERROR:删除后集合下标会发生变化* list.remove(next);*/it.remove();}}/* ERROR:删除后集合下标会发生变化* for (int i = 0; i < list.size(); i++) {if(list.get(i) % 5 == 0){list.remove(i);}}*//* ERROR:可能会抛异常java.util.ConcurrentModificationException* for (Integer i : list) {if(list.get(i) % 5 == 0){list.remove(i);}}*/System.out.println(list.toString());}

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