java常用的代码11

/**
     * 将某个日期以固定格式转化成字符串
     *
     * @param date
     * @return String
     */
    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;
    }




Java code
    /**
     * 判断任意一个整数是否素数
     *
     * @param n
     * @return boolean
     */
    public static boolean isPrimes(int n)
    {
        for (int i = 2; i <= Math.sqrt(n); i++)
        {
            if (n % i == 0)
            {
                return false;
            }
        }
        return true;
    }






 
Java code
    /**
     * 获得任意一个整数的阶乘，递归
      *
     * @param n
     * @return n!
     */
    public static int factorial(int n)
    {
        if (n == 1)
        {
            return 1;
        }
        return n * factorial(n - 1);
    }






 
Java code
    /**
     * 将指定byte数组以16进制的形式打印到控制台
     *
     * @param hint
     *            String
     * @param b
     *            byte[]
     * @return void
     */
    public static void printHexString(String hint, byte[] b)
    {
        System.out.print(hint);
        for (int i = 0; i < b.length; i++)
        {
            String hex = Integer.toHexString(b[i] & 0xFF);
            if (hex.length() == 1)
            {
                hex = '0' + hex;
            }
            System.out.print(hex.toUpperCase() + " ");
        }
        System.out.println("");
    }






 
wait();//线程等待
notify();//激活一个线程





 
我一直在用的一个字符串类库，自己写的用了很多年

Java code
package net.java2000.tools;

/**
* Title:        Java Bean 工具
* Description:
* Copyright:    Copyright (c) 2001
* Company:      JAVA世纪网 http://www.java2000.net
* @author 赵学庆
* @version 1.0
*/
import java.util.*;
import java.util.regex.Pattern;

public class StrTools {
  /**
   * 分割字符串
   *
   * @param str String 原始字符串
   * @param splitsign String 分隔符
   * @return String[] 分割后的字符串数组
   */
  @SuppressWarnings("unchecked")
  public static String[] split(String str, String splitsign) {
    int index;
    if (str == null || splitsign == null)
      return null;
    ArrayList al = new ArrayList();
    while ((index = str.indexOf(splitsign)) != -1) {
      al.add(str.substring(0, index));
      str = str.substring(index + splitsign.length());
    }
    al.add(str);
    return (String[]) al.toArray(new String[0]);
  }

  /**
   * 替换字符串
   *
   * @param from String 原始字符串
   * @param to String 目标字符串
   * @param source String 母字符串
   * @return String 替换后的字符串
   */
  public static String replace(String from, String to, String source) {
    if (source == null || from == null || to == null)
      return null;
    StringBuffer bf = new StringBuffer("");
    int index = -1;
    while ((index = source.indexOf(from)) != -1) {
      bf.append(source.substring(0, index) + to);
      source = source.substring(index + from.length());
      index = source.indexOf(from);
    }
    bf.append(source);
    return bf.toString();
  }

  /**
   * 替换字符串，能能够在HTML页面上直接显示(替换双引号和小于号)
   *
   * @param str String 原始字符串
   * @return String 替换后的字符串
   */
  public static String htmlencode(String str) {
    if (str == null) {
      return null;
    }

    return replace("\"", "&quot;", replace("<", "&lt;", str));
  }

  /**
   * 替换字符串，将被编码的转换成原始码（替换成双引号和小于号）
   *
   * @param str String
   * @return String
   */
  public static String htmldecode(String str) {
    if (str == null) {
      return null;
    }

    return replace("&quot;", "\"", replace("&lt;", "<", str));
  }

  private static final String _BR = "<br/>";

  /**
   * 在页面上直接显示文本内容，替换小于号，空格，回车，TAB
   *
   * @param str String 原始字符串
   * @return String 替换后的字符串
   */
  public static String htmlshow(String str) {
    if (str == null) {
      return null;
    }

    str = replace("<", "&lt;", str);
    str = replace(" ", "&nbsp;", str);
    str = replace("\r\n", _BR, str);
    str = replace("\n", _BR, str);
    str = replace("\t", "&nbsp;&nbsp;&nbsp;&nbsp;", str);
    return str;
  }

  /**
   * 返回指定字节长度的字符串
   *
   * @param str String 字符串
   * @param length int 指定长度
   * @return String 返回的字符串
   */
  public static String toLength(String str, int length) {
    if (str == null) {
      return null;
    }
    if (length <= 0) {
      return "";
    }
    try {
      if (str.getBytes("GBK").length <= length) {
        return str;
      }
    } catch (Exception ex) {
    }
    StringBuffer buff = new StringBuffer();

    int index = 0;
    char c;
    length -= 3;
    while (length > 0) {
      c = str.charAt(index);
      if (c < 128) {
        length--;
      } else {
        length--;
        length--;
      }
      buff.append(c);
      index++;
    }
    buff.append("...");
    return buff.toString();
  }

  /**
   * 判断是否为整数
   *
   * @param str 传入的字符串
   * @return 是整数返回true,否则返回false
   */
  public static boolean isInteger(String str) {
    Pattern pattern = Pattern.compile("^[-\\+]?[\\d]*$");
    return pattern.matcher(str).matches();
  }

  /**
   * 判断是否为浮点数，包括double和float
   *
   * @param str 传入的字符串
   * @return 是浮点数返回true,否则返回false
   */
  public static boolean isDouble(String str) {
    Pattern pattern = Pattern.compile("^[-\\+]?[.\\d]*$");
    return pattern.matcher(str).matches();
  }

  /**
   * 判断输入的字符串是否符合Email样式.
   *
   * @param str 传入的字符串
   * @return 是Email样式返回true,否则返回false
   */
  public static boolean isEmail(String str) {
    Pattern pattern = Pattern.compile("^\\w+([-+.]\\w+)*@\\w+([-.]\\w+)*\\.\\w+([-.]\\w+)*$");
    return pattern.matcher(str).matches();
  }

  /**
   * 判断输入的字符串是否为纯汉字
   *
   * @param str 传入的字符窜
   * @return 如果是纯汉字返回true,否则返回false
   */
  public static boolean isChinese(String str) {
    Pattern pattern = Pattern.compile("[\u0391-\uFFE5]+$");
    return pattern.matcher(str).matches();
  }

  /**
   * 是否为空白,包括null和""
   *
   * @param str
   * @return
   */
  public static boolean isBlank(String str) {
    return str == null || str.trim().length() == 0;
  }

  /**
   * 判断是否为质数
   *
   * @param x
   * @return
   */
  public static boolean isPrime(int x) {
    if (x <= 7) {
      if (x == 2 || x == 3 || x == 5 || x == 7)
        return true;
    }
    int c = 7;
    if (x % 2 == 0)
      return false;
    if (x % 3 == 0)
      return false;
    if (x % 5 == 0)
      return false;
    int end = (int) Math.sqrt(x);
    while (c <= end) {
      if (x % c == 0) {
        return false;
      }
      c += 4;
      if (x % c == 0) {
        return false;
      }
      c += 2;
      if (x % c == 0) {
        return false;
      }
      c += 4;
      if (x % c == 0) {
        return false;
      }
      c += 2;
      if (x % c == 0) {
        return false;
      }
      c += 4;
      if (x % c == 0) {
        return false;
      }
      c += 6;
      if (x % c == 0) {
        return false;
      }
      c += 2;
      if (x % c == 0) {
        return false;
      }
      c += 6;
    }
    return true;
  }

  public static void main(String[] args) {
    String[] numbers = { "12345", "-12345", "123.45", "-123.45", ".12345", "-.12345", "a12345", "12345a", "123.a45" };
    for (String str : numbers) {
      System.out.println(str + "=" + isInteger(str) + " " + isDouble(str));
    }

    String[] emails = { "[e-mail]", "[e-mail]", "[e-mail]" };
    for (String str : emails) {
      System.out.println(str + "=" + isEmail(str));
    }
    String[] chineses = { "中国", "1中国", "中国1", "1中国2", "中1国" };
    for (String str : chineses) {
      System.out.println(str + "=" + isChinese(str));
    }
  }
}


Java code

/* * Db.java 数据库连接的相关代码
Created on 2007年8月20日, 上午 8:37
*/
import java.io.*;
import java.sql.*;
import java.util.Properties;
public class Db {
    private String driver;
    private String url;
    private String user;
    private String password;
    private Connection conn;
    private Statement stm;
    private ResultSet rs;
    public Db(){
        this("DBConf.properties");
    }
    public Db(String conf) {
        loadProperties(conf);
        setConn();
    }
    public Connection getConn(){
        return this.conn;
    }
  //handle the properties file to get the informations for connection
    private void loadProperties(String conf){
        Properties props = new Properties();
        try {
            props.load(new FileInputStream(conf));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        this.driver = props.getProperty("driver");
        this.url = props.getProperty("url");
        this.user = props.getProperty("user");
        this.password = props.getProperty("password");
    }
    //implement the Connection
    private void setConn(){
        try {
            Class.forName(driver);
            this.conn = DriverManager.getConnection(url,user,password);
        } catch(ClassNotFoundException classnotfoundexception) {
              classnotfoundexception.printStackTrace();
            System.err.println("db: " + classnotfoundexception.getMessage());
        } catch(SQLException sqlexception) {
            System.err.println("db.getconn(): " + sqlexception.getMessage());
        }
    }
       public void doInsert(String sql) {
        try {
            Statement statement = conn.createStatement();
            int i = stm.executeUpdate(sql);
        } catch(SQLException sqlexception) {
            System.err.println("db.executeInset:" + sqlexception.getMessage());
        }
    }
    public void doDelete(String sql) {
        try {
            stm = conn.createStatement();
            int i = stm.executeUpdate(sql);
        } catch(SQLException sqlexception) {
            System.err.println("db.executeDelete:" + sqlexception.getMessage());
        }
    }
    public void doUpdate(String sql) {
        try {
            stm = conn.createStatement();
            int i = stm.executeUpdate(sql);
        } catch(SQLException sqlexception) {
            System.err.println("db.executeUpdate:" + sqlexception.getMessage());
        }
    }
   
    public ResultSet doSelect(String sql) {
        try {
            stm = conn.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY);
            rs = stm.executeQuery(sql);
        } catch(SQLException sqlexception) {
            System.err.println("db.executeQuery: " + sqlexception.getMessage());
        }
        return rs;
    }
    public static void main(String[] args){
        try{
            Db db = new Db();
            Connection conn = db.getConn();
            if(conn != null && !conn.isClosed()) {
                System.out.println("連結成功");
                ResultSet rs = db.doSelect("select * from content");
                while(rs.next()){
                    System.out.println(rs.getString(1)+":"+rs.getString(2)+":"+rs.getString(3));
                  }
                rs.close();
                conn.close();
            }
        }catch(SQLException e) {
            e.printStackTrace();
        }
    } 
}




DBConf.properties:
driver=oracle.jdbc.driver.OracleDriver
url=jdbc:oracle:thin:@tdt151:1521:train
user=XX
password=XX


数据库连接方面的代码

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class ConnectDB {
private static final String MYSQL = "jdbc:mysql://";

private static final String ORACLE = "jdbc:oracle:thin:@";

private ConnectDB() {
}

public static Connection getInstance(String DBType, String url)
throws NoSuchDBException, SQLException {
if ("mysql".equalsIgnoreCase(DBType))
return getMySqlConn(url);
if ("oracle".equalsIgnoreCase(DBType))
return getOracleConn(url);
return null;
}

public static void closeConn(Connection conn) {
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}

private static Connection getMySqlConn(String url) throws SQLException {
Connection conn = null;
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
conn = DriverManager.getConnection(MYSQL + url, "root", "root");

return conn;
}

private static Connection getOracleConn(String url) throws SQLException {
Connection conn = null;
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
conn = DriverManager.getConnection(ORACLE + url, "scott", "tiger");

return conn;
}
}


Java code
    /**
     * 人民币转成大写
     *
     * @param value
     * @return String
     */
    public static String hangeToBig(double value)
    {
        char[] hunit = { '拾', '佰', '仟' }; // 段内位置表示
        char[] vunit = { '万', '亿' }; // 段名表示
        char[] digit = { '零', '壹', '贰', '叁', '肆', '伍', '陆', '柒', '捌', '玖' }; // 数字表示
        long midVal = (long) (value * 100); // 转化成整形
        String valStr = String.valueOf(midVal); // 转化成字符串

        String head = valStr.substring(0, valStr.length() - 2); // 取整数部分
        String rail = valStr.substring(valStr.length() - 2); // 取小数部分

        String prefix = ""; // 整数部分转化的结果
        String suffix = ""; // 小数部分转化的结果
        // 处理小数点后面的数
        if (rail.equals("00"))
        { // 如果小数部分为0
            suffix = "整";
        }
        else
        {
            suffix = digit[rail.charAt(0) - '0'] + "角" + digit[rail.charAt(1) - '0'] + "分"; // 否则把角分转化出来
        }
        // 处理小数点前面的数
        char[] chDig = head.toCharArray(); // 把整数部分转化成字符数组
        char zero = '0'; // 标志'0'表示出现过0
        byte zeroSerNum = 0; // 连续出现0的次数
        for (int i = 0; i < chDig.length; i++)
        { // 循环处理每个数字
            int idx = (chDig.length - i - 1) % 4; // 取段内位置
            int vidx = (chDig.length - i - 1) / 4; // 取段位置
            if (chDig[i] == '0')
            { // 如果当前字符是0
                zeroSerNum++; // 连续0次数递增
                if (zero == '0')
                { // 标志
                    zero = digit[0];
                }
                else if (idx == 0 && vidx > 0 && zeroSerNum < 4)
                {
                    prefix += vunit[vidx - 1];
                    zero = '0';
                }
                continue;
            }
            zeroSerNum = 0; // 连续0次数清零
            if (zero != '0')
            { // 如果标志不为0,则加上,例如万,亿什么的
                prefix += zero;
                zero = '0';
            }
            prefix += digit[chDig[i] - '0']; // 转化该数字表示
            if (idx > 0)
                prefix += hunit[idx - 1];
            if (idx == 0 && vidx > 0)
            {
                prefix += vunit[vidx - 1]; // 段结束位置应该加上段名如万,亿
            }
        }

        if (prefix.length() > 0)
            prefix += '圆'; // 如果整数部分存在,则有圆的字样
        return prefix + suffix; // 返回正确表示
    }
数据库连接地址返回代码
public static String getURLByDBInfo(DBInfo dbInfo)
    {
        String url = "";
        if(dbInfo.getDbType() != null)
            if(dbInfo.getDbType().equals("SQLSERVER"))
                url = (new StringBuilder("jdbc:microsoft:sqlserver://")).append(dbInfo.getDbHost()).append(":").append(dbInfo.getDbPort()).append(";DatabaseName=").append(dbInfo.getDbSID()).toString();
            else
            if(dbInfo.getDbType().equals("ORACLE"))
                url = (new StringBuilder("jdbc:oracle:thin:@")).append(dbInfo.getDbHost()).append(":").append(dbInfo.getDbPort()).append(":").append(dbInfo.getDbSID()).toString();
            else
            if(dbInfo.getDbType().equals("ORACLE_DSP"))
                url = (new StringBuilder("jdbc:dsp@")).append(dbInfo.getDbHost()).append(":").append(dbInfo.getDbPort()).append("/").append(dbInfo.getDbSID()).append("/").append(dbInfo.getNamespace()).toString();
            else
            if(dbInfo.getDbType().equals("SYBASE"))
                url = "jdbc:sybase:Tds:...";
            else
                url = "sun.jdbc.odbc.JdbcOdbcDriver";
        return url;
    }


Java code
    /**
     * 全角字符转半角字符
     *
     * @param QJStr
     * @return String
     */
    public static final String QJToBJChange(String QJStr)
    {
        char[] chr = QJStr.toCharArray();
        String str = "";
        for (int i = 0; i < chr.length; i++)
        {
            chr[i] = (char) ((int) chr[i] - 65248);
            str += chr[i];
        }
        return str;
    }
Java code
    /**
     * 去掉字符串中重复的子字符串
     *
     * @param str
     * @return String
     */
    private static String removeSameString(String str)
    {
        Set<String> mLinkedSet = new LinkedHashSet<String>();
        String[] strArray = str.split(" ");
        StringBuffer sb = new StringBuffer();

        for (int i = 0; i < strArray.length; i++)
        {
            if (!mLinkedSet.contains(strArray[i]))
            {
                mLinkedSet.add(strArray[i]);
                sb.append(strArray[i] + " ");
            }
        }
        System.out.println(mLinkedSet);
        return sb.toString().substring(0, sb.toString().length() - 1);
    }
Java code

    /**
     * 设置JSpinner的编辑属性
     * @param spinner 目标JSpinner
     * @param isAllowInvalid 是否允许输入非法值
     * @param isEditable 是否允许编辑
     */
    public static void setAllowsInvalid(JSpinner spinner, boolean isAllowInvalid, boolean isEditable)
    {
        JSpinner.NumberEditor editor = new JSpinner.NumberEditor(spinner, "#");
        spinner.setEditor(editor);
        JFormattedTextField tf = ((JSpinner.NumberEditor)spinner.getEditor()).getTextField();
        tf.setEditable(isEditable);
        DefaultFormatterFactory factory = (DefaultFormatterFactory)tf.getFormatterFactory();
        NumberFormatter formatter = (NumberFormatter)factory.getDefaultFormatter();
        formatter.setAllowsInvalid(isAllowInvalid);
    }

/**  
     * 根据指定方法的参数去构造一个新的对象的拷贝并将他返回
     * @param obj 原始对象
     * @return 新对象
     * @throws NoSuchMethodException   
     * @throws InvocationTargetException   
     * @throws IllegalAccessException   
     * @throws InstantiationException   
     * @throws SecurityException   
     * @throws IllegalArgumentException   
     */
    @SuppressWarnings("unchecked")
    public static Object copy(Object obj) throws IllegalArgumentException, SecurityException, InstantiationException, IllegalAccessException,
                    InvocationTargetException, NoSuchMethodException
    {
        //获得对象的类型   
        Class classType = obj.getClass();

        //通过默认构造方法去创建一个新的对象，getConstructor的视其参数决定调用哪个构造方法   
        Object objectCopy = classType.getConstructor(new Class[]{}).newInstance(new Object[]{});

        //获得对象的所有属性   
        Field[] fields = classType.getDeclaredFields();

        for(int i = 0; i < fields.length; i++)
        {
            //获取数组中对应的属性   
            Field field = fields[i];

            String fieldName = field.getName();
            String stringLetter = fieldName.substring(0, 1).toUpperCase();

            //获得相应属性的getXXX和setXXX方法名称   
            String getName = "get" + stringLetter + fieldName.substring(1);
            String setName = "set" + stringLetter + fieldName.substring(1);

            //获取相应的方法   
            Method getMethod = classType.getMethod(getName, new Class[]{});
            Method setMethod = classType.getMethod(setName, new Class[]{field.getType()});

            //调用源对象的getXXX（）方法   
            Object value = getMethod.invoke(obj, new Object[]{});

            //调用拷贝对象的setXXX（）方法   
            setMethod.invoke(objectCopy, new Object[]{value});
        }

        return objectCopy;
    }