java——MD5密码隐藏（不可逆）

Main.java:

package com.jd.test; import java.util.Scanner; import java.util.UUID; import com.jd.tool.MD5Tool; import com.jd.tool.db.DBLink; public class Main { public static void main(String[] args) { System.out.println("*********************************"); System.out.println("*\t\t\t\t*"); System.out.println("*\t欢迎使用注册登录系统\t\t*"); System.out.println("*\t\t\t\t*"); System.out.println("*********************************"); while (true) { menu(); } } static void menu() { System.out.println("1、注册");//用户名 密码 确认密码 System.out.println("2、登录");//用户名和密码 System.out.println("3、退出");//System.exit(0); System.out.println("请输入操作，以Enter键结束:"); Scanner scanner = new Scanner(System.in); int option = scanner.nextInt(); switch (option) { case 1:{ System.out.println("请输入用户名"); String userName=scanner.next(); System.out.println("请输入密码"); String passWord=scanner.next(); System.out.println("请确认密码"); String repassWord=scanner.next(); String sql="select id from user_info where user_name=?"; if(new DBLink().exist(sql,userName)) { System.out.println("用户名被占用，操作终止"); return; } if(!passWord.equals(repassWord)) { System.out.println("密码不一致，操作终止"); } String id=UUID.randomUUID().toString(); passWord=MD5Tool.encrypt(passWord); sql="insert into user_info (id,user_name,password) values('"+id+"',?,?)"; if(new DBLink().update(sql,userName,passWord)) { System.out.println("注册成功"); return; } System.out.println("注册失败"); break; } case 2:{ System.out.println("请输入用户名"); String userNames=scanner.next(); System.out.println("请输入密码"); String passWords=scanner.next(); passWords=MD5Tool.encrypt(passWords); String sql="select id from user_info where user_name=? and password=?"; if(new DBLink().exist(sql,userNames,passWords)) { System.out.println("登陆成功"); return; } System.out.println("用户名或密码错误"); break; } case 3:{ System.out.println("退出"); System.exit(0); } default: System.out.println("I'm Sorry,there is not the "+option+" option,please try again."); } } }

DBLink.java:

package com.jd.tool.db; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import org.apache.log4j.Logger; import com.jd.tool.PropertiesTool; /** * 数据库管理工具类 * * @author 10164 */ public class DBLink { private Logger logger=Logger.getLogger(DBLink.class); /** * 获取数据库链接 * * @author 10164 */ private Connection getConnection() { try { Class.forName("com.mysql.jdbc.Driver"); String userName = PropertiesTool.getValue("db.username"); String password = PropertiesTool.getValue("db.password"); String url = PropertiesTool.getValue("db.url"); return DriverManager.getConnection(url, userName, password); } catch (Exception e) { logger.debug(e.getMessage(),e); } return null; } /** * 查询数据 * * @author 10164 */ public void select(String sql,IRowMapper rowMapper) { Connection connection = null; Statement statement =null; ResultSet resultSet=null; try { connection=getConnection(); statement = connection.createStatement(); resultSet= statement.executeQuery(sql); rowMapper.rowmapper(resultSet); } catch (Exception e) { logger.debug(e.getMessage(),e); }finally { close(resultSet,statement,connection); } } /** * 修改数据 * * @author 10164 */ public boolean update(String sql) { Connection connection=null; Statement statement=null; try { connection=getConnection(); statement=connection.createStatement(); int result=statement.executeUpdate(sql); //statement.close(); //connection.close(); return result>0; }catch(Exception e) { logger.debug(e.getMessage(),e); }finally { close(statement,connection); } return false; } /** * 释放资源 * * @author 10164 */ private void close(Statement statement,Connection connection) { try { if(statement!=null) { statement.close(); } } catch (SQLException e) { e.printStackTrace(); } try { if(connection!=null) { connection.close(); } } catch (SQLException e) { logger.debug(e.getMessage(),e); } } /** * 判断SQL语句是否能查出数据 * * @author 10164 */ public boolean exist(String sql) { Connection connection = null; Statement statement =null; ResultSet resultSet=null; try { connection = getConnection(); statement = connection.createStatement(); resultSet= statement.executeQuery(sql); return resultSet.next(); } catch (Exception e) { logger.debug(e.getMessage(),e); }finally { close(resultSet,statement,connection); } return false; } /** * 判断SQL语句是否能查出数据 * * @author 10164 */ public boolean exist(String sql,Object ...params) { Connection connection = null; PreparedStatement preparedStatement =null; ResultSet resultSet=null; try { connection = getConnection(); preparedStatement = connection.prepareStatement(sql); for (int i = 0; i < params.length; i++) { preparedStatement.setObject(i+1, params[i]); } resultSet= preparedStatement.executeQuery(); return resultSet.next(); } catch (Exception e) { logger.debug(e.getMessage(),e); }finally { close(resultSet,preparedStatement,connection); } return false; } /** * 释放资源 * * @author 10164 */ private void close(ResultSet resultSet,Statement statement,Connection connection) { try { if(resultSet!=null) { resultSet.close(); } } catch (SQLException e) { logger.debug(e.getMessage(),e); } try { if(statement!=null) { statement.close(); } } catch (SQLException e) { logger.debug(e.getMessage(),e); } try { if(connection!=null) { connection.close(); } } catch (SQLException e) { logger.debug(e.getMessage(),e); } } public boolean update(String sql,Object ...params) { Connection connection=null; PreparedStatement preparedStatement=null; try { connection=getConnection(); preparedStatement=connection.prepareStatement(sql); for (int i = 0; i < params.length; i++) { preparedStatement.setObject(i+1, params[i]); } return preparedStatement.executeUpdate()>0; } catch (Exception e) { logger.debug(e.getMessage(),e); }finally { close(preparedStatement,connection); } return false; } public void select(String sql,IRowMapper rowMapper,Object ...params) { Connection connection = null; PreparedStatement preparedStatement =null; ResultSet resultSet=null; try { connection=getConnection(); preparedStatement = connection.prepareStatement(sql); for (int i = 0; i < params.length; i++) { preparedStatement.setObject(i+1, params[i]); } resultSet= preparedStatement.executeQuery(); rowMapper.rowmapper(resultSet); } catch (Exception e) { logger.debug(e.getMessage(),e); }finally { close(resultSet,preparedStatement,connection); } } }

IRowMapper.java:

package com.jd.tool.db; import java.sql.ResultSet; public interface IRowMapper { void rowmapper (ResultSet rs); }

MD5Tool.java:

package com.jd.tool; import java.math.BigInteger; import java.security.MessageDigest; public class MD5Tool { public static String encrypt(String password) { byte[] bytes = null; try { MessageDigest messageDigest = MessageDigest.getInstance("MD5"); messageDigest.update(password.getBytes());//加密 bytes = messageDigest.digest();//获得加密结果 } catch (Exception e) { e.printStackTrace(); } String result = new BigInteger(1, bytes).toString(16);// 将加密后的数据转换为16进制数字 // 生成数字未满32位，则前面补0 for (int i = 0; i < 32 - result.length(); i++) { result = "0" + result; } return result; } }

PropertiesTool.java:

package com.jd.tool; import java.io.IOException; import java.io.InputStream; import java.util.Properties; public class PropertiesTool { private static Properties properties = new Properties(); static { InputStream inputStream = PropertiesTool.class.getClassLoader().getResourceAsStream("db.properties"); try { properties.load(inputStream); } catch (IOException e) { e.printStackTrace(); } } public static String getValue(String key) { return properties.getProperty(key); } }

db.properties:

db.username=root db.password=root db.url=jdbc:mysql://127.0.0.1:3306/test

log4j.properties:

# DEBUG\u8BBE\u7F6E\u8F93\u51FA\u65E5\u5FD7\u7EA7\u522B\uFF0C\u7531\u4E8E\u4E3ADEBUG\uFF0C\u6240\u4EE5ERROR\u3001WARN\u548CINFO \u7EA7\u522B\u65E5\u5FD7\u4FE1\u606F\u4E5F\u4F1A\u663E\u793A\u51FA\u6765 log4j.rootLogger=DEBUG,Console,RollingFile #\u5C06\u65E5\u5FD7\u4FE1\u606F\u8F93\u51FA\u5230\u63A7\u5236\u53F0 log4j.appender.Console=org.apache.log4j.ConsoleAppender log4j.appender.Console.layout=org.apache.log4j.PatternLayout log4j.appender.Console.layout.ConversionPattern= [%-5p]-[%d{yyyy-MM-dd HH:mm:ss}] -%l -%m%n #\u5C06\u65E5\u5FD7\u4FE1\u606F\u8F93\u51FA\u5230\u64CD\u4F5C\u7CFB\u7EDFD\u76D8\u6839\u76EE\u5F55\u4E0B\u7684log.log\u6587\u4EF6\u4E2D log4j.appender.RollingFile=org.apache.log4j.DailyRollingFileAppender log4j.appender.RollingFile.File=C://logger//logger.log log4j.appender.RollingFile.layout=org.apache.log4j.PatternLayout log4j.appender.RollingFile.layout.ConversionPattern=%d [%t] %-5p %-40.40c %X{traceId}-%m%n