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import java.util.Calendar;
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import java.util.Date;
public class Countdown2 implements Runnable {
public static void main(String[] args) {
Thread cd = new Thread(new Countdown2());
cd.start();
}
@Override
public void run() {
// 设置日期2012-12-21
Calendar c = Calendar.getInstance();
c.set(2016, 1, 1, 0, 0, 0);
// 单独设置年、月、日、小时、分钟、秒
c.set(Calendar.YEAR, 2015);
c.set(Calendar.MONTH, Calendar.DECEMBER); // 0 表示1月,11 表示12月
c.set(Calendar.DAY_OF_MONTH, 21);
c.set(Calendar.HOUR_OF_DAY, 0);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
// 获取2012-12-21 0:0:0时间点对应的毫秒数
long endTime = c.getTimeInMillis();
// 获取系统当前时间
Date now = new Date();
// 获取当前时间点对应的毫秒数
long currentTime = now.getTime();
// 计算两个时间点相差的秒数
long seconds = (endTime - currentTime) / 1000;
while (true) {
long days = seconds / (3600 * 24);
long h = seconds % (3600 * 24) / 3600;
long m = seconds % (3600 * 24) % 3600 / 60;
long s = seconds % (3600 * 24) % 3600 % 60;
System.out.println("离2016年元旦还剩: " + days + "天" + h + "小时" + m + "分" + s + "秒");
seconds--;
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
获取系统时间:
import java.util.*;
import java.text.*;
public class TestDate {
public static void main(String[] args) {
Calendar ca = Calendar.getInstance();
int year = ca.get(Calendar.YEAR);//获取年份
int month=ca.get(Calendar.MONTH);//获取月份
int day=ca.get(Calendar.DATE);//获取日
int minute=ca.get(Calendar.MINUTE);//分
int hour=ca.get(Calendar.HOUR);//小时
int second=ca.get(Calendar.SECOND);//秒
int WeekOfYear = ca.get(Calendar.DAY_OF_WEEK);
}
用系统时间跟生日比较就行了
java虚拟机加载资源文件和加载类一样。如果资源文件和类放在一起,资源文件也需要加上包名。
还有可能是资源冲突了。看看这个
改为,你的boolean数组没有初始化,bar[0]取到的为null,if(null){} 编译通不过去
1. String foo = “blue”;
2. Boolean[] bar = {true};
3. if (bar[0]) {
4. foo = “green”;
5. }
代码如下,随便附一句,一定要看写的源码,我已经尽量马马虎虎的写了,你更容易看懂。
public class Test {
// 第八题
public static final int NUM = 100;
public static final double GOOD = 99.99;
public static final String CLASSNAME = "Test.Class";
public static final long MAX = 9999999;
public static void main(String[] args) {
// 第一题
byte byte1 = 1;
short short1 = 1;
int int1 = 1;
long long1 = 1;
float float1 = 1;
double double1 = 1.0;
System.out.println("byte1 - " + byte1);
System.out.println("short1 - " + short1);
System.out.println("int1 - " + int1);
System.out.println("long1 - " + long1);
System.out.println("float1 - " + float1);
System.out.println("double1 - " + double1);
// 第二题
String name;
char sex;
int age;
boolean isMember;
// 第三题
int score1;
double score2 = 98.5;
// 第四题
double f1 = 10.1, f2 = 34.2;
System.out.println("f1,f2的和:" + (f1 + f2));
System.out.println("f1,f2的差:" + (f1 - f2));
System.out.println("f1,f2的积:" + (f1 * f2));
System.out.println("f1,f2的商:" + (f1 / f2));
// 第五题
int f3 = 5;
double f4 = 45.6;
System.out.println("f3,f4的和:" + (f3 + f4));
System.out.println("f3,f4的差:" + (f3 - f4));
System.out.println("f3,f4的积:" + (f3 * f4));
System.out.println("f3,f4的商:" + (f3 / f4));
// 第六题
int A = 65;
char a = (char) A;
System.out.println("整型互转char:" + a);
// 第七题
double timor = 123.456789;
int x = Integer
.parseInt(new java.text.DecimalFormat("0").format(timor));// 四舍五入
System.out.println("double - int :" + x);
// 第八题(定义在最开始)
System.out.println("常量NUM的值: " + NUM);
System.out.println("常量GOOD的值: " + GOOD);
System.out.println("常量CLASSNAME的值: " + CLASSNAME);
System.out.println("常量MAX的值: " + MAX);
// 第九题(自定义商品类)
class Goods {
private String name;
private double price;
private int count;
private double total;
public Goods(String name, double price, int count) {
this.name = name;
this.price = price;
this.count = count;
}
public void print() {
total = price * count;
System.out.println("商品名 价格 数量 总价");
System.out.println(name + " " + price + " " + count + " "
+ total);
}
}
Goods goods = new Goods("苹果", 2, 10);
goods.print();
// 第十题
double pi = 3.14, r, d;
r = 4;
d = 2 * r;
System.out.println("圆的周长: " + (pi * d));
System.out.println("圆的面积: " + (pi * r * r));
// 第十一题
String qqname = "1234567890";
String qqpassword = "asd!#@#$%66";
Date birth = new Date(2014, 5, 1);
boolean isVIP = false;
char sex1 = '男';
StringBuilder personInfo = new StringBuilder();
personInfo.append("我是一个快乐的骚年");
personInfo
.append("然后a!#$%^*asdasdasdasdsa9d87a9s8d79asdjidauisdhausdihiasd");
// 第十二题
class Swaper {
public void change(int num1, int num2) {
int temp = num1;
num1 = num2;
num2 = temp;
System.out.printf("a=%d,b=%d\n", num1, num2);
}
}
int a1 = 2;
int b1 = 5;
Swaper swaper = new Swaper();
swaper.change(a1, b1);
}
}
class NoLowerLetterException extends Exception {
public NoLowerLetterException(String msg) {
super(msg);
}
}
class NoDigitException extends Exception {
public NoDigitException(String msg) {
super(msg);
}
}
class People {
void printLetter(char c) {
if (c = 'a' c = 'z') {
System.out.println(c);
} else {
try {
throw new NoLowerLetterException(String.valueOf(c));
} catch (NoLowerLetterException e) {
e.printStackTrace();
}
}
}
void printDigit(char c) {
if (c = '0' c = '9') {
System.out.println(c);
} else {
try {
throw new NoDigitException(String.valueOf(c));
} catch (NoDigitException e) {
e.printStackTrace();
}
}
}
}
public class ExceptionExample {
public static void main(String args[]) {
People people = new People();
for (int i = 0; i 128; i++) {
// 【代码5】
// //将i转换为char类型,执行people.printLetter()方法,如果出现异常则捕获,并输出异常的错误信息!
people.printLetter((char) i);
}
for (int i = 0; i 128; i++) {
// 【代码6】 //将i转换为char类型,执行people. printDigit
// ()方法,如果出现异常则捕获,并输出异常的错误信息!
people.printDigit((char) i);
}
}
}