数组的三种声明方式总结、多维数组的遍历、Arrays类的常用方法总结

public class WhatEver {
    public static void main(String[] args) {
        //第一种   例:
        String[] test1 = new String[6];
        test1[0] = "数组0";
        test1[1] = "数组1";


        //第二种 例:
        String[] test2 = {"数组0","数组1","数组2","...."};

        //第三种 例:
        String[] test3 = new String[]{"数组0","数组1","数组2","...."};



    }
}

//二维数组
public class Test1 {
    public static void main(String[] args) {
        int[] score1=new int[10];
        int[][] score2;
        String[][] names;
        //二维数组的初始化
        score2=new int[][]{{1,2,3},{3,4,5,6},{16,7}};//静态初始化
        names=new String[6][5];//动态初始化方式一
        names=new String[6][];//动态初始化方式二，一定要设置行数
        names[0]=new String[5];//第一行中有5个元素
        names[1]=new String[4];
        names[2]=new String[7];
        names[3]=new String[5];
        names[4]=new String[8];
        names[5]=new String[5];
        System.out.println("第一行中的元素："+names[1].length);
        System.out.println(names.length);//打印的是二维数组有几行

        //如何遍历二维数组
        for(int m=0;m<score2.length;m++){//控制行数
            for(int n=0;n<score2[m].length;n++){//一行中有多少个元素（即多少列）
                System.out.print(score2[m][n]+" ");
            }
            System.out.println();
        }


    }

}

1 @SafeVarargs
2     public static <T> List<T> asList(T... a) {
3         return new ArrayList<>(a);
4     }

1 List<String> stringList = Arrays.asList("Welcome", "To", "Java",
2         "World!");
3 
4     List<Integer> intList = Arrays.asList(1, 2, 3, 4);

1 String[] names2 = { "Eric", "John", "Alan", "Liz" };
2 
3 
4     //[Eric, John, Alan]
5     String[] copy = Arrays.copyOf(names2, 3);
6     
7     //[Alan, Liz]
8     String[] rangeCopy = Arrays.copyOfRange(names2, 2,
9         names2.length);

1 String[] names = { "Liz", "John", "Eric", "Alan" };
2 //只排序前两个
3 //[John, Liz, Eric, Alan]
4 Arrays.sort(names, 0, 2);
5 //全部排序
6 //[Alan, Eric, John, Liz]
7 Arrays.sort(names);

1 public static <T> void sort(T[] a, Comparator<? super T> c) {
2         if (LegacyMergeSort.userRequested)
3             legacyMergeSort(a, c);
4         else
5             TimSort.sort(a, c);
6     }

String[] names = { "Liz", "John", "Eric", "Alan" };
  Arrays.sort(names);
  System.out.println(Arrays.toString(names));