java System类和Arrays类详解

package com.Test;
import Test2.MyDate;
import java.awt.*;
import java.text.ParseException;
import java.text.SimpleDateFORMat;
import java.util.Calendar;
import java.util.Date;
import java.util.GreGorianCalendar;
import java.util.Properties;

public class Main {

private final static String name = "磊哥的java历险记-@51博客";


public static void main(String[] args) {
//构造方法被私有 不能创建对象
//System sy = new System();
//public static void exit(int status) //退出程序，0为正常状态，其他为异常状态
// System.out.println("我要退出了！");
// System.exit(0);
// System.out.println("我已经退出了！");
//public static long currentTimeMillis() //获取当前时间毫秒值
long timeMillis = System.currentTimeMillis();
long time = new Date().getTime();
long timeInMillis = Calendar.getInstance().getTimeInMillis();
System.out.println(timeMillis);
for(int i = 0; i < 5; i++) {
System.out.println("i love java");
}
long timeMillis2 = System.currentTimeMillis();
System.out.println(timeMillis2-timeMillis);
//publicstatic Properties getProperties() //获取某个属性信息
Properties properties = System.getProperties();
System.out.println(properties);
System.out.println("============="+name+"=============");
}
}

package com.Test;
import java.util.Arrays;

public class Test{
private final static String name = "磊哥的java历险记-@51博客";
public static void main(String args[]){

//定义数组
int[] score={1,2,3};
int[] scores={1,2,3};
//数组之间比较，长度，值相等，则认为两个数组相等，返回布尔值
System.out.println("比较值和长度："+Arrays.equals(score,scores));
//判断地址
if(score==scores){
System.out.println("score和scores比较，相等");
}else{
System.out.println("score和scores比较，不相等");
}
//定义二维数组
int[][] sc={{222,333,1,2,0},{1,2,3,2,0}};
//排序
Arrays.sort(sc[1]);
System.out.println("排序："+Arrays.toString(sc[1]));
System.out.println("按照下标取值:"+sc[0][1]+" ");

//定义数据se
int[] se={1,2,3,4,5};
//填充数组
Arrays.fill(se,0);
System.out.println("填充："+Arrays.toString(se));
//复制值到sx，增加指定长度
int[] sx=Arrays.copyOf(se,2);
//输出sx的填充后的值
System.out.println("复制2："+Arrays.toString(sx));
int[] xb={14,20,67,34,33,23,10};
//排序xb
Arrays.sort(xb);
System.out.println(Arrays.toString(xb));
//在排序后，通过二分查找，找到34的元素，并返回下标
int index1=Arrays.binarySearch(xb,34);
System.out.println("二分法取值："+index1);
System.out.println("============="+name+"=============");
}
}

package com.Test;

import java.util.Arrays;


public class Main {
private final static String name = "磊哥的java历险记-@51博客";
public static void main(String[] args){
//创建int类型数组A，A的值为{1,2,3,4,5}
int[]A = new int[]{1,2,3,4,5};
//将A的值拷贝进长度为6的B中
int[]B = Arrays.copyOf(A, 6);
//比较A和B是否相同
System.out.println("两个数组是否相等："+Arrays.equals(A, B));
System.out.println("============="+name+"=============");
}
}