Java开发工具类

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工具包

===============================================================

ConfigUtil .java 文件

package util;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class ConfigUtil {

   private static Properties props=new Properties();
   static {
       ClassLoader loader=ConfigUtil.class.getClassLoader();
       InputStream ips=loader.getResourceAsStream("util/config.properties");
       try {
           props.load(ips);
       } catch (IOException e) {
           e.printStackTrace();
       }
   }
   public static String getProperty(String key){
       return props.getProperty(key);
   }
   public static void main(String[] args){
       System.out.println("EmploryDAO");

   }

}

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config.properties 文件

ComputerDAO=dao.impl.ComputerDAOJdbcImpl
#StudentDAO=dao.impl.StudentDAOHibernateImpl

===============================================================

DBUtil.java 文件

package util;

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

/**
* jdbc工具类
* @author Administrator
*/
public class DBUtil {
   public static Connection getConnection() throws Exception{
       Connection conn = null;
       try {
           Class.forName("com.mysql.jdbc.Driver");
           conn = DriverManager.getConnection(
                   "jdbc:mysql://127.0.0.1:3306/bookshopping?useUnicode=true&characterEncoding=utf8","root","qq@qq.com");
       } catch (Exception e) {
           e.printStackTrace();
           throw e;
       }
       return conn;
   }

   public static void close(Connection conn){
       if(conn !=null){
           try {
               conn.close();
           } catch (SQLException e) {
               e.printStackTrace();
           }
       }
   }
   public static void main(String[] args) throws Exception {
       System.out.println(getConnection());

   }

}

===============================================================

Factory.java 文件

package util;
/**
* 工厂类
* @author Administrator
*
*/
public class Factory {
   public static Object getInstance(String type) throws Exception{
       Object obj = null;
       //依据接口名(type)，返回该接口对应的实现类的名称
       String className = ConfigUtil.getProperty(type);
       //通过反射机制，创建某个类的实例
       try {
           obj = Class.forName(className).newInstance();
       } catch (Exception e) {
           e.printStackTrace();
           throw e;
       }
       return obj;
   }
}

===============================================================

MD5Util.java 文件

package util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import sun.misc.BASE64Encoder;

public class MD5Util {
   public static void test1(){
       try {
           MessageDigest md =
               MessageDigest.getInstance("md5");
           String str = "ihateyouasdfasdfasdf";
           byte[] buf = md.digest(str.getBytes());
           BASE64Encoder encoder =
               new BASE64Encoder();
           String str2 = encoder.encode(buf);
           System.out.println("str2:" + str2 + " " + str2.length());
       } catch (NoSuchAlgorithmException e) {
           e.printStackTrace();
       }
   }

   public static String getMD5Str(String origStr) throws Exception{
           MessageDigest md =
               MessageDigest.getInstance("md5");
           byte[] buf = md.digest(origStr.getBytes());
           BASE64Encoder encoder =
               new BASE64Encoder();
           String str2 = encoder.encode(buf);
           return str2;

   }
   /**
   * @param args
   */
   public static void main(String[] args) {
       // TODO Auto-generated method stub
       test1();
   }

}