MD5加密

1、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，点击Enter键"); String user_name = scanner.next(); System.out.println("请输入密码，点击Enter键"); String password = scanner.next(); System.out.println("请再次输入密码，点击Enter键"); String rePassword = scanner.next(); String sql = "select id from user_info where user_name=?"; if(new DBLink().exist(sql, user_name)) { System.out.println("该用户名已存在，请重新输入"); return; } if(!password.equals(rePassword)){ System.out.println("密码不一致"); return; } 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,user_name,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，点击Enter键"); String user_name = scanner.next(); System.out.println("请输入密码，点击Enter键"); String password = scanner.next(); password = MD5Tool.encrypt(password); String sql = "select id from user_info where user_name=? and password=?"; if(new DBLink().exist(sql, user_name,password)) { System.out.println("登录成功！"); return; } System.out.println("登录失败！"); break; } case 3:{ System.out.println("已成功退出"); System.exit(0); } default: System.out.println("I'm Sorry,there is not the "+option+" option,please try again."); } } }

2、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; public class DBLink { private Logger logger = Logger.getLogger(DBLink.class); /** * 获取数据连接 * * @author 样光伊 */ 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) { //e.printStackTrace(); //将异常显示在控制台上 logger.debug(e.getMessage(), e); } return null; } /** * 判断数据是否存在 * * @author 样光伊 */ 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; } /** * 判断数据是否存在 * * @author 样光伊 */ public boolean exist(String sql,Object ...params) { //避免exist()方法SQL注入 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; } /** * 修改（insert、delete、update）数据 * * @author 样光伊 */ public boolean update(String sql) {//不能使用private，否则update只能被本类中的对象调用 Connection connection = null; Statement statement = null; try { connection = getConnection(); statement = connection.createStatement(); int affect = statement.executeUpdate(sql); return affect>0; } catch (Exception e) { logger.debug(e.getMessage(), e); }finally { close(statement,connection); } return false; } /** * 修改（insert、delete、update）数据（避免了SQL注入） * * @author 样光伊 */ public boolean update(String sql,Object ...params) {//Object ...params是动态参数，只能放在参数列表的最后面 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; } /** * 查询数据 * * @author 样光伊 */ public void select(String sql,IRowMapper rowMapper) { Connection connection = null; close(resultSet,statement,connection)都是非静态方法 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); } } /** * 查询数据（避免了SQL注入） * * @author 样光伊 */ 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) { e.printStackTrace(); } finally { close(resultSet,preparedStatement,connection); } } /** * 关闭资源 * * @author 样光伊 */ private void close(Statement statement,Connection connection) { 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); } } /** * 关闭资源 * * @author 样光伊 */ private void close(ResultSet resultSet,Statement statement,Connection connection) { try { if(resultSet!=null) { resultSet.close(); } } catch (SQLException e) { logger.debug(e.getMessage(), e); } close(statement,connection); } }

3、IRowMapper.java

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

4、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; } }

5、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");//将db.properties变为javaIO流对象inputStream try { properties.load(inputStream); } catch (IOException e) { e.printStackTrace(); } } public static String getValue(String string) { return properties.getProperty(string); } }

6、db.properties

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

7、log4j.properties

# DEBUG设置输出日志级别，由于为DEBUG，所以ERROR、WARN和INFO 级别日志信息也会显示出来 log4j.rootLogger=DEBUG,RollingFile #将日志信息输出到控制台 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 #将日志信息输出到操作系统D盘根目录下的log.log文件中 log4j.appender.RollingFile=org.apache.log4j.DailyRollingFileAppender log4j.appender.RollingFile.File=D://log.log log4j.appender.RollingFile.layout=org.apache.log4j.PatternLayout log4j.appender.RollingFile.layout.ConversionPattern=%d [%t] %-5p %-40.40c %X{traceId}-%m%n