项目结构
工具
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=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
db.properties：存放连接数据库时的用到的数据，这样修改连接的设备时不需从java文件中修改
db.user_name = root;
db.password = root;
db.url =jdbc:mysql://127.0.0.1:3306/test1;
PropertiesTool：架起DBLink和db.properties之间的桥梁
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
try {
properties.load(inputStream);//将inputStream通过 load方法把key
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String [] ages) {
String userName = properties.getProperty("db.username");
System.out.print(userName);
}
public static String getValue(String key) {
return properties.getProperty(key);
}
}
MD5Tool：加密工具
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;
}
}
IRowMapper：函数式接口
package com.jd.tool.db.aa;
import java.sql.ResultSet;
public interface IRowMapper {
void rowMapper(ResultSet rs);
}
DBLink：jdbc用到的方法
package com.jd.tool.db.aa;
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;
/**
* sql管理工具类
*
* @author SONG
*/
public class DBLink {
private static Logger logger = Logger.getLogger(DBLink.class);
/*try {
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://127.0.0.1:3306/test1";
connection=DriverManager.getConnection(url, "root", "root");
statement = connection.createStatement();
long result = statement.executeLargeUpdate(sql);
statement.close();//如果上面代码出现异常，则该行代码及其下面代码无法执行，所以资源无法释放；比如sql语句语法错误，则statement和connection无法释放
connection.close();*/
/**
* 获取数据库连接
*
*@author SONG
*/
private static 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) {
// TODO Auto-generated catch block
logger.debug(e.getMessage(),e);
}
return null;
}
/**
* 查询数据
*
*@author SONG
*/
public void select(String sql,IRowMapper rowMapper ) {//接口无法创建对象，所以rowMapper参数一定指向IRowMapper接口实现类对象
//此处的rowMapper就是一个形参，到时候接口实现类里的实参再传给它
Connection connection =null;
Statement statement =null;
ResultSet resultSet =null;
try {
connection = getConnection();
statement = connection.createStatement();
resultSet = statement.executeQuery(sql);
rowMapper.rowMapper(resultSet);//因为rowMapper参数指向IRowMapper接口实现类对象，所以此处将调用接口实现类中所实现的rowMapper方法 多态
} catch (Exception e) {
logger.debug(e.getMessage(),e);
}finally {
close(resultSet,statement,connection);
}
}
/**
* 查询数据
*
*@author SONG
*/
public void select(String sql,IRowMapper rowMapper, Object ...pramas ) {//接口无法创建对象，所以rowMapper参数一定指向IRowMapper接口实现类对象
//此处的rowMapper就是一个形参，到时候接口实现类里的实参再传给它
Connection connection =null;
Statement statement =null;
ResultSet resultSet =null;
PreparedStatement preparedStatement =null;
try {
connection = getConnection();
preparedStatement = connection.prepareStatement(sql);//含有？占位符的sql
for (int i = 0; i < pramas.length; i++) {
preparedStatement.setObject(i+1, pramas[i]);//为？赋值
}
resultSet = preparedStatement.executeQuery();
rowMapper.rowMapper(resultSet);//因为rowMapper参数指向IRowMapper接口实现类对象，所以此处将调用接口实现类中所实现的rowMapper方法 多态
} catch (Exception e) {
logger.debug(e.getMessage(),e);
}finally {
close(resultSet,preparedStatement,connection);
}
}
/**
* 判断sql语句能否查出数据
*
*@author SONG
*/
public boolean exist(String sql) {//接口无法创建对象，所以rowMapper参数一定指向IRowMapper接口实现类对象
//此处的rowMapper就是一个形参，到时候接口实现类里的实参再传给它
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 {
try {
if(resultSet!=null){
resultSet.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
close(resultSet,statement,connection);
}
return false;
}
/**
* 判断sql语句能否查出数据
*
*@author SONG
*/
public boolean exist(String sql,Object ...pramas) {//接口无法创建对象，所以rowMapper参数一定指向IRowMapper接口实现类对象
//此处的rowMapper就是一个形参，到时候接口实现类里的实参再传给它
Connection connection =null;
PreparedStatement preparedStatement =null;
ResultSet resultSet =null;
try {
connection = getConnection();
preparedStatement = connection.prepareStatement(sql);//含有？占位符的sql
for (int i = 0; i < pramas.length; i++) {
preparedStatement.setObject(i+1, pramas[i]);//为？赋值
}
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 SONG
*/
public boolean update(String sql) {
Connection connection=null;
Statement statement=null;
try {
connection=getConnection();
statement = connection.createStatement();
long result = statement.executeLargeUpdate(sql);
return result>0;
} catch (Exception e) {
logger.debug(e.getMessage(),e);
}finally {
close(statement,connection);
}
return false;
}
/**
* 修改（insert delete update）数据
*
*@author SONG
*/
public static boolean update(String sql,Object ...pramas) {
Connection connection=null;
PreparedStatement preparedStatement=null;
try {
connection = getConnection();
preparedStatement=connection.prepareStatement(sql);//含有？占位符的sql
for (int i = 0; i < pramas.length; i++) {
preparedStatement.setObject(i+1, pramas[i]);//为？赋值
}
return preparedStatement.executeUpdate()>0;
}catch(Exception e) {
logger.debug(e.getMessage(),e);
}finally {
close(preparedStatement,connection);
}
return false;
}
/**
* 释放资源
*
*@author SONG
*/
private static 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);
}
}
/**
* 释放资源
*
*@author SONG
*/
private static 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);
}
}
Main：实现功能
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欢迎使用用户登录注册系统\t\t*");
System.out.println("*\t\t\t\t*");
System.out.println("*********************************");
while (true) {
menu();
}
}
static void menu() {
System.out.println("1登录");//用户名 密码 确认密码
System.out.println("2注册");//用户名，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 user_name = scanner.next();
System.out.println("请输入密码");
String password = scanner.next();
password = MD5Tool.encrypt(password);//将密码通过MD5算法得到一串36位十六进制的数字
String sql = "select id from user_info where user_name =? and password = ?";
if (new DBLink().exist(sql,password)) {
System.out.println("登录成功");
return;
}
System.out.println("登录失败");
break;
}
case 2:{
System.out.println("请输入用户名");
String user_name = scanner.next();
String sql = "select id from user_info where user_name =?";
if (new DBLink().exist(sql,user_name)) {
System.out.println("用户名不允许重复");
return;
}
System.out.println("请输入密码");
String password = scanner.next();
System.out.println("请确认密码");
String password1 = scanner.next();
if (!password.equals(password1)) {
System.out.println("密码不一致，注册失败");
break;
}
String id =UUID.randomUUID().toString();
password = MD5Tool.encrypt(password);//将密码通过MD5算法得到一串36位十六进制的数字
sql = "insert into user_info(id,user_name,password) value('"+id+"',?,?)";
if (new DBLink().update(sql,user_name,password)) {
System.out.println("注册成功");
break;
}
System.out.println("注册失败");
break;
}
case 3:{
System.out.println("退出成功");
System.exit(0);//关闭程序,不需要return或者break了
}
default:
System.out.println("I'm Sorry,there is not the "+option+" option,please try again.");
}
}
}
版权声明：本文为syhfly2333原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接和本声明。