TestCollections类
package cn.sxt.collection;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class TestCollections {
public static void main(String[] args) {
List<String> list = new ArrayList<>();
for(int i = 0 ; i < 10; i++){
list.add("ma" + i);
}
System.out.println(list);
//随机排列list元素
Collections.shuffle(list);
System.out.println(list);
//逆序排列list元素
Collections.reverse(list);
System.out.println(list);
//递增排列list元素
Collections.sort(list);
System.out.println(list);
//二分查找制定元素
System.out.println(Collections.binarySearch(list, "ma7"));
}
}
运行结果：
[ma0, ma1, ma2, ma3, ma4, ma5, ma6, ma7, ma8, ma9]
[ma7, ma1, ma4, ma9, ma0, ma3, ma5, ma2, ma8, ma6]
[ma6, ma8, ma2, ma5, ma3, ma0, ma9, ma4, ma1, ma7]
[ma0, ma1, ma2, ma3, ma4, ma5, ma6, ma7, ma8, ma9]
7
总结
Collections是工具类，Collection是接口，二者不同!
