java中简单的函数代码 java中简单的函数代码是什么

Java 的代码，50行，要三个函数，要有循环

随便给你写了一个

package com.wys.util;

import java.util.ArrayList;

import java.util.List;

import java.util.Random;

public class Test {

public static ListInteger smallNumbers,largeNumbers;

public static int sum1 = 0,sum2 = 0;

public static void main(String[] args) {

smallNumbers = new ArrayListInteger();

largeNumbers = new ArrayListInteger();

run();

}

public static void run() {

int i = 0;

for (int j = 0; j 50; j++) {

Random rand = new Random();

i = rand.nextInt(1000);

if (i500) {

small(i);

}else{

large(i);

}

}

System.out.println("随机输出的50个数字中:");

System.out.println("大于500的数（包括500）共有"+largeNumbers.size()+"个");

System.out.print("他们是"+largeNumbers);

System.out.println();

System.out.println("他们的和是"+sum1);

System.out.println("小于500的数共有"+smallNumbers.size()+"个");

System.out.print("他们是"+smallNumbers);

System.out.println();

System.out.println("他们的和是"+sum2);

}

private static void large(int number) {

largeNumbers.add(number);

sum1 += number;

}

private static void small(int number) {

smallNumbers.add(number);

sum2 += number;

}

}

相关问答

Q1: java中读字符的函数代码!

/**

* @version 1.0

* @author 韩卫召

*

* 多种方式读文件的内容

* 按字节读取文件内容,按字符读取文件的内容,按行读取文件的内容,随即读取文件的内容

*/

import java.io.BufferedReader;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.RandomAccessFile;

import java.io.Reader;

import java.util.ResourceBundle;

public class ReadFromFile {

/**

* 以字节为单位读取文件的内容,常用于二进制文件,如声音,图象,影象等文件

*

* @param filename

* 文件名

*/

public static void readFileByBytes(java.lang.String filename) {

File file = new File(filename);

InputStream in = null;

System.out.println("以字节为单位读取文件的内容,一次读一个字节: ");

// 一次读一个字节

try {

in = new FileInputStream(file);

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

int tempbyte;

try {

// 不断的读取,直到文件结束

while ((tempbyte = in.read()) != -1) {

System.out.write(tempbyte);

}

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

try {

in.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

return;

}

System.out.println("以字节为单位读取文件内容,一次读多个字节: ");

// 一次读取多个字节

byte[] tempbytes = new byte[100];

int byteread = 0;

try {

in = new FileInputStream(filename);

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

ReadFromFile.showAvailabelBytes(in);

try {

while ((byteread = in.read(tempbytes)) != -1) {

// 读取多个字节到数组中,byteead为一次读取的字节数

System.out.write(tempbytes, 0, byteread);

}

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public static void readFileByteChars(java.lang.String filename) {

/**

* 以字符为单位读取文件,常用与读文本,数字等类型的文件

*/

File file = new File(filename);

Reader reader = null;

System.out.println("以字符为单位读取文件内容,一次读一个字节: ");

// 一次读一个字符

try {

reader = new InputStreamReader(new FileInputStream(file));

} catch (FileNotFoundException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}

int tempchar;

try {

while ((tempchar = reader.read()) != -1) {

// 在Window下,\r\n这两个字符在一起时,表示一个换行

// 但如果这两个字符分开显示时,会换行两次行

// 因此,屏蔽掉\r,或者\n;否则,将会多出来很多空行

if (((char) tempchar) != '\r') {

System.out.println((char) tempchar);

}

}

reader.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

System.out.println("以字符为单位读取文件内容,一次读多个字符: ");

char[] tempchars = new char[30];

int charread = 0;

try {

reader = new InputStreamReader(new FileInputStream(filename));

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

try {

// 读入多个字符到字符数组中,charread为一次读取字符数

while ((charread = reader.read(tempchars)) != -1) {

if ((charread == tempchars.length)

(tempchars[tempchars.length - 1] != '\r')) {

System.out.println(tempchars);

} else {

for (int i = 0; i charread; i++) {

if (tempchars[i] == '\r') {

continue;

} else {

System.out.print(tempchars[i]);

}

}

}

}

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} finally {

if (reader != null) {

try {

reader.close();

} catch (IOException e) {

}

}

}

}

public static void readFileByLines(java.lang.String filename) {

File file = new File(filename);

BufferedReader reader = null;

// System.out.println("以行为单位读取文件的内容,一次读一整行: ");

try {

reader = new BufferedReader(new FileReader(file));

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

java.lang.String tempString = null;

int line = 1;

try {

while ((tempString = reader.readLine()) != null) {

if(tempString.indexOf("福州")!=-1){

System.out.println("靠！出错了！赶紧报警啊！ " + line + ": " + tempString);

}

// System.out.println("line " + line + ": " + tempString);

line++;

}

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

try {

reader.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} finally {

if (reader != null) {

try {

reader.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}

public static void readFileByRandomAccess(java.lang.String filename) {

RandomAccessFile randomFile = null;

System.out.println("随即读取一段文件内容: ");

try {

randomFile = new RandomAccessFile(filename, "r");

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

long fileLength = 0;

try {

fileLength = randomFile.length();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

int beginIndex = (fileLength 4) ? 4 : 0;

try {

randomFile.seek(beginIndex);

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

byte[] bytes = new byte[10];

int byteread = 0;

try {

while ((byteread = randomFile.read(bytes)) != -1) {

System.out.write(bytes, 0, byteread);

}

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} finally {

if (randomFile != null) {

try {

randomFile.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}

private static void showAvailabelBytes(InputStream in) {

try {

System.out.println("当前字节输入流中的字节数为: " + in.available());

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public static void main(java.lang.String args[]) {

ResourceBundle rb = ResourceBundle.getBundle("PreventTampering");

String filePath = rb.getString("filePath");

java.lang.String filename = filePath+"test.txt";

System.out.println(filename);

// ReadFromFile.readFileByBytes(filename);

// ReadFromFile.readFileByteChars(filename);

ReadFromFile.readFileByLines(filename);

// ReadFromFile.readFileByRandomAccess(filename);

}

Q2: java常用函数方法

Java的一些常用函数,方法总结：

1:数组方面:

数组是一个对象,数组名可以理解和C++里面一样,

1):System.arraycopy(src,srcindex,dst,dstindex,src.length);

2):java.util.Arrays.sort(数组名);//块数排序法进行排序

3):java.util.Arrays.binarySearch(arr,key);//从哪里收,关键值,返回索引.没有的话返回-1

4):java.util.Array.fill(arr,value),设置数组初始值

5):Array.equals(arr1,arr2)//比较两个数组中元素是不是全部相等,是返回true,不是返回false

2:时间方面:

public static String dateToStr(java.util.Date date)

{

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

String str = sdf.format(date);

return str;

}

import java.text.SimpleDateFormat;

import java.util.Calendar;

public class DateUtil

{

public static java.util.Date parseDate(String dateStr, String format)

{

java.util.Date date = null;

try

{

java.text.DateFormat df = new java.text.SimpleDateFormat(format);

String dt = dateStr.replaceAll("-", "/");

if ((!dt.equals("")) (dt.length() format.length()))

{

dt += format.substring(dt.length()).replaceAll("[YyMmDdHhSs]", "0");

}

date = (java.util.Date) df.parse(dt);

}

catch (Exception e)

{

}

return date;

}

public static java.util.Date parseDate(String dateStr)

{

return parseDate(dateStr, "yyyy/MM/dd");

}

public static String format(java.util.Date date, String format)

{

String result = "";

try

{

if (date != null)

{

java.text.DateFormat df = new java.text.SimpleDateFormat(format);

result = df.format(date);

}

}

catch (Exception e)

{

}

return result;

}

public static String format(java.util.Date date)

{

return format(date, "yyyy/MM/dd");

}

public static int getYear(java.util.Date date)

{

java.util.Calendar c = java.util.Calendar.getInstance();

c.setTime(date);

return c.get(java.util.Calendar.YEAR);

}

public static int getMonth(java.util.Date date)

{

java.util.Calendar c = java.util.Calendar.getInstance();

c.setTime(date);

return c.get(java.util.Calendar.MONTH) + 1;

}

public static int getDay(java.util.Date date)

{

java.util.Calendar c = java.util.Calendar.getInstance();

c.setTime(date);

return c.get(java.util.Calendar.DAY_OF_MONTH);

}

public static int getHour(java.util.Date date)

{

java.util.Calendar c = java.util.Calendar.getInstance();

c.setTime(date);

return c.get(java.util.Calendar.HOUR_OF_DAY);

}

public static int getMinute(java.util.Date date)

{

java.util.Calendar c = java.util.Calendar.getInstance();

c.setTime(date);

return c.get(java.util.Calendar.MINUTE);

}

public static int getSecond(java.util.Date date)

{

java.util.Calendar c = java.util.Calendar.getInstance();

c.setTime(date);

return c.get(java.util.Calendar.SECOND);

}

public static long getMillis(java.util.Date date)

{

java.util.Calendar c = java.util.Calendar.getInstance();

c.setTime(date);

return c.getTimeInMillis();

}

public static String getDate(java.util.Date date)

{

return format(date, "yyyy/MM/dd");

}

public static String getTime(java.util.Date date)

{

return format(date, "HH:mm:ss");

}

public static String getDateTime(java.util.Date date)

{

return format(date, "yyyy/MM/dd HH:mm:ss");

}

public static java.util.Date addDate(java.util.Date date, int day)

{

java.util.Calendar c = java.util.Calendar.getInstance();

c.setTimeInMillis(getMillis(date) + ((long) day) * 24 * 3600 * 1000);

return c.getTime();

}

public static int diffDate(java.util.Date date, java.util.Date date1)

{

return (int) ((getMillis(date) - getMillis(date1)) / (24 * 3600 * 1000));

}

public static String getMonthBegin(String strdate)

{

java.util.Date date = parseDate(strdate);

return format(date, "yyyy-MM") + "-01";

}

public static String getMonthEnd(String strdate)

{

java.util.Date date = parseDate(getMonthBegin(strdate));

Calendar calendar = Calendar.getInstance();

calendar.setTime(date);

calendar.add(Calendar.MONTH, 1);

calendar.add(Calendar.DAY_OF_YEAR, -1);

return formatDate(calendar.getTime());

}

public static String formatDate(java.util.Date date)

{

return formatDateByFormat(date, "yyyy-MM-dd");

}

public static String formatDateByFormat(java.util.Date date, String format)

{

String result = "";

if (date != null)

{

try

{

SimpleDateFormat sdf = new SimpleDateFormat(format);

result = sdf.format(date);

}

catch (Exception ex)

{

ex.printStackTrace();

}

}

return result;

}

}

Java日期格式化及其使用例子

1 SimpleDateFormat担当重任,怎样格式化都行

import java.util.Date;

import java.text.SimpleDateFormat;

public class Demo

{

public static void main(String[] args)

{

Date now=new Date();

SimpleDateFormat f=newSimpleDateFormat("今天是"+"yyyy年MM月dd日 E kk点mm分");

System.out.println(f.format(now));

f=new SimpleDateFormat("a hh点mm分ss秒");

System.out.println(f.format(now));

}

}

2 从字符串到日期类型的转换：

import java.util.Date;

import java.text.SimpleDateFormat;

import java.util.GregorianCalendar;

import java.text.*;

publicclass Demo

{

public static void main(String[] args)

{

String strDate="2005年04月22日";

//注意：SimpleDateFormat构造函数的样式与strDate的样式必须相符

SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy年MM月dd日");

//必须捕获异常

try

{

Date date=simpleDateFormat.parse(strDate);

System.out.println(date);

}

catch(ParseException px)

{

px.printStackTrace();

}

}

}

3 将毫秒数换转成日期类型

import java.util.Date;

import java.text.SimpleDateFormat;

import java.util.GregorianCalendar;

import java.text.*;

public class Demo

{

public static void main(String[] args)

{

long now=System.currentTimeMillis();

System.out.println("毫秒数："+now);

Date dNow=new Date(now);

System.out.println("日期类型："+dNow);

}

}

4 获取系统时期和时间，转换成SQL格式后更新到数据库

java.util.Date d=new java.util.Date(); //获取当前系统的时间

//格式化日期

new java.text.SimpleDateFormat s= new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

String dateStr = s.format(d); //转为字符串

使用RS更新数据库，仍然要用rs.updateString，而不是rs.updateDade。

rs.updateString("regtime",dateStr); //regtime字段为datetime类型的

5 按本地时区输出当前日期

Date myDate = new Date();

System.out.println(myDate.toLocaleString());

输出结果为：

2003-5-30

6 如何格式化小数

DecimalFormat df = new DecimalFormat(",###.00");

double aNumber = 33665448856.6568975;

String result = df.format(aNumber);

Sytem. out.println(result);

输出结果为：

33,665,448,856.66

其他：获取毫秒时间 System.currentTimeMillis();

7 在数据库里的日期只以年-月-日的方式输出

定义日期格式：SimpleDateFormat sdf = new SimpleDateFormat(yy-MM-dd);

sql语句为：String sqlStr = "select bookDate from roomBook where bookDate between '2007-4-10' and '2007-4-25'";

输出：

System.out.println(df.format(rs.getDate("bookDate")));

Q3: Java语言里面如何调用函数，请给出一段调用函数的代码？

public class HelloWord{

//自定义的输出函数，打印字符串helloword！

public void printHelloWord() {

System.out.println("helloword!");

}

public static void main(String args[]){

//创建对象实例

HelloWord hw = new HelloWord();

//通过对象实例调用自己的成员函数

hw.printHelloWord() ;

}

}

你看看满意不？

Q4: 求一段简单的java代码 写一个简单的函数比如y=sin(x) 然后调用该函数得到结果y(pi/2)=1

帮你写好了.

public class AAA {

public static void main (String[] args){

double PI, y;

PI = 4 * Math.atan(1.0);

y = F(0.5*PI);

System.out.println(y);

}

public static double F (double x){

return Math.sin(x);

}

}

java中简单的函数代码的介绍就聊到这里吧，感谢你花时间阅读本站内容，更多关于java中简单的函数代码是什么、java中简单的函数代码的信息别忘了在本站进行查找喔。