java在系统中增加提示音 java提示语句

常用的Java语句
1.取得日期，格式为2013-10-14

Calendar calendar = Calendar.getInstance(); 

String to_date = new SimpleDateFormat("yyyy-MM-dd").format(calendar.getTime()); 

//取得前5天日期from_date 

calendar.add(Calendar.DATE, -5); 

String from_date = new SimpleDateFormat("yyyy-MM-dd").format(calendar.getTime()); 

//取得前一个月的日期 

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

String from_date = new SimpleDateFormat("yyyy-MM-dd").format(calendar.getTime());

2.四舍五入 scale：要保留的小数位

public static String round(double value, int scale) { 

 if(value==0.5){//0.5四舍五入有误，故加上0.00000001校正 

 value=0.50000001; 

 } 

 String temp = Math.abs(value) < 1 ? "0":"###,###"; 

 if (scale > 0) { 

 temp += "."; 

 for (int i = 0; i < scale; i++) { 

 temp += "0"; 

 } 

 } 

 return new DecimalFormat(temp).format(value); 

 }

3.验证是否是数字

private static boolean isNumeric(String str) { 

 try{ 

 Double.parseDouble(str); 

 }catch (Exception e) { 

 return false; 

 } 

 return true; 

 }

4.判断字符串是否为空

public static boolean isNull(String str){ 

 return str==null || "".equals(str.trim()) || "NULL".equalsIgnoreCase(str.trim()) || "undefined".equalsIgnoreCase(str.trim()) || "NaN".equalsIgnoreCase(str.trim()); 

 }

5.文件读写处理

//读文件 

 public static String readFileToString(String filePath,String encoding){ 

 File file=null; 

 InputStream input = null; 

 try { 

 file=new File(filePath); 

 if(file.exists()){ 

 input = new FileInputStream(file); 

 return IOUtils.toString(input, encoding); 

 } 

 }catch (Exception e) { 

 logger.error("读取文件异常。"+e.getMessage()); 

 } 

 finally { 

 IOUtils.closeQuietly(input); 

 } 

 return ""; 

 } 

 // 写文件 

 public static void writeFile(String filePath, String data, String encoding) { 

 File file = null; 

 OutputStream output = null; 

 try { 

 if (data != null) { 

 file = new File(filePath); 

 output = new FileOutputStream(file); 


 if (encoding == null) { 

 IOUtils.write(data, output); 

 } else { 

 output.write(data.getBytes(encoding)); 

 } 

 } 

 } catch (Exception e) { 

 logger.error("写入文件异常。" + e.getMessage()); 

 } finally { 

 IOUtils.closeQuietly(output); 

 } 

 } 

 // 写文件 

 public static void writeFile(String filePath, InputStream inputStream, String encoding) { 

 try { 

 BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream)); 

 StringBuilder sb = new StringBuilder(); 


 String line = null; 

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

 sb.append(line + "\n"); 

 } 

 writeFile( filePath, sb.toString(), encoding); 


 } catch (Exception e) { 

 e.printStackTrace(); 

 logger.error("写入文件异常。" + e.getMessage()); 

 }finally { 

 try { 

 inputStream.close(); 

 } catch (IOException e) { 

 e.printStackTrace(); 

 } 

 } 

 }

6.将list集合组成字符串

/** 

 * @specification :提取list中表头列,形成字符串a,b,c 

 * @param list: list列 

 * @param flag: 提取map中key值 

 * @param initStr: 初始化字符串 

 * @return :String 

 * @exception :Exception 

 */ 

 public static String getStrFromList(List list,String flag,String initStr) { 

 // TODO Auto-generated method stub 

 //将字符串大写，方便获取map值 

 flag = flag.toUpperCase(); 

 String flagStr = ""; 


 //获取当前用户、页面对应的条件 

 String condition = initStr; 

 if(list != null && list.size() > 0){ 

 for(int i=0;i<list.size();i++){ 

 Map map = (Map) list.get(i); 

 flagStr +="," + map.get(flag); 

 } 

 } 

 if(flagStr != null && !"".equals(flagStr)){ 

 condition = flagStr.substring(1); 

 } 


 return condition; 

 }

7.Java反射

/*** 

 * 

 * @specification :通过方法名，寻找反射相应的方法，获得变量值 

 * @param :frac_value 方法名 FormMRFractileInfo 类对象 

 * @return :方法对应的值 

 * @exception : 

 */ 

 public static String getMethodValue(String frac_value,Object frc) { 

 // TODO Auto-generated method stub 

 String rating_number = null ; 

 // 获取反射类 

 Class frc_class = frc.getClass(); 

 Method frc_method; 

 try { 

 // 获取反射方法 

 frc_method = frc_class.getDeclaredMethod(frac_value); 

 // 获取值 

 rating_number = (String) frc_method.invoke(frc); 

 } catch (SecurityException e) { 

 // TODO Auto-generated catch block 

 e.printStackTrace(); 

 } catch (NoSuchMethodException e) { 

 // TODO Auto-generated catch block 

 e.printStackTrace(); 

 } catch (IllegalArgumentException e) { 

 // TODO Auto-generated catch block 

 e.printStackTrace(); 

 } catch (IllegalAccessException e) { 

 // TODO Auto-generated catch block 

 e.printStackTrace(); 

 } catch (InvocationTargetException e) { 

 // TODO Auto-generated catch block 

 e.printStackTrace(); 

 } 

 return rating_number; 

 } 


 /*** 

 * 

 * @param value 

 * @specification :通过方法名，寻找反射相应的方法，设置变量值 

 * @param :frac_value 方法名 FormMRFractileInfo 类对象 

 * @return :方法对应的值 

 * @exception : 

 */ 

 public static void setMethodValue(String frac_value,Object frc, String value) { 

 // 获取反射类 

 Class frc_class = frc.getClass(); 

 Method frc_method; 

 try { 

 // 获取反射方法 

 frc_method = frc_class.getDeclaredMethod(frac_value, new Class[]{java.lang.String.class}); 

 // 设置值 

 frc_method.invoke(frc, value); 

 } catch (SecurityException e) { 

 // TODO Auto-generated catch block 

 e.printStackTrace(); 

 } catch (NoSuchMethodException e) { 

 // TODO Auto-generated catch block 

 e.printStackTrace(); 

 } catch (IllegalArgumentException e) { 

 // TODO Auto-generated catch block 

 e.printStackTrace(); 

 } catch (IllegalAccessException e) { 

 // TODO Auto-generated catch block 

 e.printStackTrace(); 

 } catch (InvocationTargetException e) { 

 // TODO Auto-generated catch block 

 e.printStackTrace(); 

 } 

 }

8.截屏

public static void main(String[] args) { 

 try { 

 int width = (int)Toolkit.getDefaultToolkit().getScreenSize().getWidth(); 

 int height = (int)Toolkit.getDefaultToolkit().getScreenSize().getHeight(); 

 Robot robot = new Robot(); 

 BufferedImage image = robot.createScreenCapture(new Rectangle(width,height)); 

 ImageIO.write (image, "png" , new File("E:/1.jpg")); 


 } catch (AWTException e) { 

 e.printStackTrace(); 

 } catch (IOException e) { 

 e.printStackTrace(); 

 } 

 }

9.excel2007读写-POI

private static void test(String strPath) throws Exception{ 

 XSSFWorkbook xwb; 

 xwb = new XSSFWorkbook(strPath); 

 XSSFSheet sheet = xwb.getSheetAt(0); 

// 读取第一章表格内?? 

// 定义 row、cell 

 XSSFRow row; 

 String cell; 

// 循环输出表格中的内容 

 for (int i = sheet.getFirstRowNum(); i < sheet.getPhysicalNumberOfRows(); i++ ) { 

 row = sheet.getRow(i); 

 for (int j = row.getFirstCellNum(); j < row.getPhysicalNumberOfCells(); j++ ) { 

// 通过 row.getCell(j).toString() 获取单元格内容， 

 cell = row.getCell(j)!=null?row.getCell(j).toString():""; 

 System.out.print(cell+"\t"); 

 } 

 System.out.println(""); 

 }

}
测试：test("F:\\11.xlsx");


10.获取IP地址对应的MAC地址

/** 

 * 

 * @Title: 

 * @Description: 同工ip取得对应的mac值 

 * @param @param args 设定文件 

 * @return 返回类型 

 * @throws 

 */ 

 public String getMACAddress(String ip){ 

 String str = ""; 

 String macAddress = ""; 


 try { 

 Process p = Runtime.getRuntime().exec("nbtstat -A " + ip); 

 InputStreamReader ir = new InputStreamReader(p.getInputStream()); 

 LineNumberReader input = new LineNumberReader(ir); 

 for (int i = 1; i < 100; i++) { 

 str = input.readLine(); 

 if (str != null) { 

 if (str.indexOf("MAC") > 1) { 

 macAddress = str.substring(str.indexOf("MAC Address") + 14, str.length()); 

 System.out.println(ip+"/macAddress==="+macAddress); 

 break; 

 } 

 } 

 } 

 } catch (IOException e) { 

 e.printStackTrace(System.out); 

 } 


 return macAddress; 

 }

测试：getMACAddress("10.1.1.1")


11.获取随机数

/** 

 * 

 * @Title: 

 * @Description: 取得随机数据 

 * @param @param args 设定文件 

 * @return 返回类型 

 * @throws 

 */ 

 public static void main(String[] args) { 

 Random rd = new Random(); 

 //随机正数 

 System.out.println(Math.abs(Math.random()*10)); 

 //随机正整数 

 System.out.println(Math.abs(rd.nextInt())%10); 

 }

12.获取当前系统物理文件夹

//取得目前程序所在电脑系统用户、用户文档地址、当前代码物理地址 

System.out.println("user_name:" + System.getProperty("")); 

 System.out.println("user_home:" + System.getProperty("user.home")); 

 System.out.println("user_dir:" + System.getProperty("user.dir"));

13.socket连接

package test; 


import java.io.DataInputStream; 

import java.io.DataOutputStream; 

import java.io.IOException; 

import .ServerSocket; 

import .Socket; 

import .UnknownHostException; 

import java.util.ArrayList; 


public class TestSocket { 

 public static void main(String[] args) { 

 try { 

 ArrayList a = new ArrayList(); 

 a.add(a); 

 //socket接收 

 ServerSocket soc = new ServerSocket(6666); 

 // 服务器接收到客户端的数据后，创建与此客户端对话的Socket 

 Socket socket = soc.accept(); 


// 用于向客户端发送数据的输出流 

 DataOutputStream dos = new DataOutputStream(socket.getOutputStream()); 

// 用于接收客户端发来的数据的输入流 

 DataInputStream dis = new DataInputStream(socket.getInputStream()); 


 System.out.println("服务器接收到客户端的连接请求：" + dis.readUTF()); 

// 服务器向客户端发送连接成功确认信息 

 dos.writeUTF("接受连接请求，连接成功!"); 

// 不需要继续使用此连接时，关闭连接 

 socket.close(); 

 soc.close(); 

 } catch (IOException e) { 

 // TODO Auto-generated catch block 

 e.printStackTrace(); 

 } 

 } 

 //客户端socket 

 void cilentSocketDemo(){ 


 Socket socket = null; 

 try { 

 socket = new Socket("localhost",6666);//ip,端口 


 //获取输出流，用于客户端向服务器端发送数据 

 DataOutputStream dos = new DataOutputStream(socket.getOutputStream()); 

 //获取输入流，用于接收服务器端发送来的数据 

 DataInputStream dis = new DataInputStream(socket.getInputStream()); 

 //客户端向服务器端发送数据 

 dos.writeUTF("我是客户端，请求连接!"); 


 //打印出从服务器端接收到的数据 

 System.out.println(dis.readUTF()); 

 //不需要继续使用此连接时，记得关闭哦 

 socket.close(); 

 } catch (UnknownHostException e) { 

 // TODO Auto-generated catch block 

 e.printStackTrace(); 

 } catch (IOException e) { 

 // TODO Auto-generated catch block 

 e.printStackTrace(); 

 } 


 } 

}