学生管理系统（用maven来导入jar包）

不废话，直接上

先看一下项目列表：

首先创建一个maven工程，然后导入相应的jar包，请参考：使用maven导入jar包

接着在Source Folder创建具体的项目：

Main类（客户端）

package com.zzu.client;import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Scanner;import com.zzu.tool.db.DBLink;
import com.zzu.tool.db.IRowMapper;public class Main {public static void main(String[] args) {System.out.println("*********************************");System.out.println("*\t\t\t\t*");System.out.println("*\t欢迎使用学生信息管理系统\t*");System.out.println("*\t\t\t\t*");System.out.println("*********************************");while (true) {menu();}}static void menu() {System.out.println("1、添加学生信息");System.out.println("2、删除学生信息");//学号System.out.println("3、修改学生信息");//地址传递System.out.println("4、查询学生信息");//nameSystem.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("请输入学号：");String id = scanner.next();String sql = "select id from student where id = ?";if(new DBLink().exist(sql, id)) {System.out.println("学号已存在，无法添加！");return;}System.out.println("请输入姓名：");String name = scanner.next();System.out.println("请输入手机号：");String mobile = scanner.next();System.out.println("请输入家庭住址：");String address = scanner.next();sql = "insert into student (id,name,mobile,address) values (?,?,?,?)";if(new DBLink().update(sql, id,name,mobile,address)) {System.out.println("添加成功!");return;}System.out.println("添加失败！");break;}case 2:{System.out.println("请输入要删除学生的学号：");String id = scanner.next();String sql = "delete from student where id = ?";if(new DBLink().update(sql, id)) {System.out.println("删除成功！");return;}System.out.println("删除失败！");break;}case 3:{System.out.println("请输入要修改学生的学号：");String id = scanner.next();String sql = "select id from student where id = ?";if(new DBLink().exist(sql, id)) {System.out.println("请输入新的姓名：");String name = scanner.next();System.out.println("请输入新的手机号：");String mobile = scanner.next();System.out.println("请输入新的家庭住址：");String address = scanner.next();sql = "update student set name = ?,mobile = ?, address = ? where id = ?";if(new DBLink().update(sql, name,mobile,address,id)) {System.out.println("修改成功！");return;}System.out.println("修改失败！");return;}System.out.println("未查询到要修改学生的学号！");break;}case 4:{System.out.println("请输入要查询学生的学号：");String id = scanner.next();String sql = "select id from student where id = ?";if(!new DBLink().exist(sql, id)) {System.out.println("学号不存在，无法查询！");}sql = "select id,name,mobile,address from student where id = ?";//有名内部类class RowMapper implements IRowMapper{public void rowMapper(ResultSet rs) {try {if(rs.next()) {String id1 = rs.getString("id");String name = rs.getString("name");String mobile = rs.getString("mobile");String address = rs.getString("address");System.out.println("学号："+id1+",姓名："+name+",手机号："+mobile+",家庭住址："+address);}} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}};RowMapper rowMapper = new RowMapper();new DBLink().select(sql, rowMapper,id);//Lambda表达式/*new DBLink().select(sql, (ResultSet rs)->{try {if(rs.next()) {String id1 = rs.getString("id");String name = rs.getString("name");String mobile = rs.getString("mobile");String address = rs.getString("address");System.out.println("学号："+id1+",姓名："+name+",手机号："+mobile+",家庭住址："+address);}} catch (SQLException e) {e.printStackTrace();}},id);*/break;}default:System.out.println("I'm Sorry,there is not the "+option+" option,please try again.");}}
}

DBLink（工具类）

package com.zzu.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.zzu.tool.PropertiesTool;/*** 数据库管理（增删改查）* * @author ZhaoZhengyi*/public class DBLink {private Logger logger = Logger.getLogger(DBLink.class);/*** 获取数据库连接** @author ZhaoZhengyi*/public  Connection getConnection() {try {String driver = PropertiesTool.getValue("db.driver");String   url    = PropertiesTool.getValue("db.url");String userName = PropertiesTool.getValue("db.userName");String password = PropertiesTool.getValue("db.password");Class.forName(driver);return DriverManager.getConnection(url, userName, password);} catch (Exception e) {logger.debug(e.getMessage(), e);}return null;}/*** 该方法用于判断某个用户是否存在，若存在返回该用户数据，否则返回false* @param sql 是指要执行的SQL语句* @return*//*public boolean exist(String sql) {//初始化变量为nullConnection connection = null;Statement statement = null;ResultSet resultset = null;try {connection = getConnection();statement = connection.createStatement();//创建SQL语句对象		resultset = statement.executeQuery(sql);//executeQuery用于查询用户的数据，并将其存入ResultSet类型的resultset变量中去return resultset.next();//若有则返回该用户数据} catch (Exception e) {logger.debug(e.getMessage(), e);} finally {//即便有异常也会执行代码close(resultset,statement,connection);//释放资源}return false;}*//*** 判断某条数据是否存在** @author ZhaoZhengyi*/public boolean exist(String sql,Object ...params) {//初始化变量为nullConnection connection = null;PreparedStatement prepareStatement = null;ResultSet resultset = null;try {connection = getConnection();prepareStatement = connection.prepareStatement(sql);//此时prepareStatement为含有?的sql语句for (int i = 0; i < params.length; i++) {//为？赋值，这里之所以为i+1，是因为该方法是从1开始的prepareStatement.setObject(i+1, params[i]);}resultset = prepareStatement.executeQuery();//executeQuery用于查询用户的数据，并将其存入ResultSet类型的resultset变量中去return resultset.next();//若有则返回该用户数据} catch (Exception e) {logger.debug(e.getMessage(), e);} finally {//即便有异常也会执行代码close(resultset,prepareStatement,connection);//释放资源}return false;//若没有则返回false}/*** 该方法用于insert（添加）、delete（删除）、update（修改）用户信息* 至于选哪一个来操作用户信息因sql语句而定* @param sql 是指要操作的SQL语句* @return 若成功则返回影响的行数，否则返回false*/public boolean update(String sql) {Connection connection = null;Statement statement = null;try {connection = getConnection();statement = connection.createStatement();//创建SQL语句对象		int affect = statement.executeUpdate(sql);//执行sql语句，返回影响的行数，仅限于insert delete update/*statement.close();connection.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return affect>0;/** 这里我想说明一下，由于finally的特殊性，会先执行完finally里的释放资源，再执行上一语句：返回一个affect值* 总之就是在结束方法之前无论如何都要先释放资源才可以*/} catch (Exception e) {logger.debug(e.getMessage(), e);} finally {//即便有异常也会执行代码close(statement,connection);//释放资源}return false;}/*** 用于添加、删除、修改用户信息** @author ZhaoZhengyi*/public boolean update(String sql, Object ...params) {Connection connection = null;PreparedStatement  prepareStatement = null;try {connection = getConnection();prepareStatement = connection.prepareStatement(sql);//含有?的sql语句 赋值给prepareStatementfor(int i = 0; i < params.length; i++) {prepareStatement.setObject(i+1, params[i]);//用参数替换掉？}int affect = prepareStatement.executeUpdate();//执行sql语句，并返回影响的行数return affect>0;} catch (Exception e) {logger.debug(e.getMessage(), e);} finally {close(prepareStatement,connection);}return false;}//获取某个表中的总行数（分页使用）public Object getValue(String sql,String columnName) {Connection connection = null;Statement statement = null;ResultSet resultset = null;try {connection = getConnection();statement = connection.createStatement();resultset = statement.executeQuery(sql);if(resultset.next()) {return resultset.getObject(columnName);}} catch (Exception e) {logger.debug(e.getMessage(), e);} finally {close(resultset,statement,connection);}return null;}//获取某个表中的总行数（分页使用）(防止sql注入)public Object getValue(String sql,String columnName,Object ...params) {Connection connection = null;PreparedStatement prepareStatement = null;ResultSet resultset = null;try {connection = getConnection();prepareStatement = connection.prepareStatement(sql);for (int i = 0; i < params.length; i++) {prepareStatement.setObject(i+1, params[i]);}resultset = prepareStatement.executeQuery();if(resultset.next()) {return resultset.getObject(columnName);}} catch (Exception e) {logger.debug(e.getMessage(), e);} finally {close(resultset,prepareStatement,connection);}return null;}/*** 该方法用于查询用户信息* @param sql 要执行的SQL语句* @param rowMapper 接口是无法创建对象的，所以参数rowMapper一定指向接口(IRowMapper)实现类对象*/public void select(String sql,IRowMapper rowMapper) {Connection connection = null;Statement statement = null;ResultSet resultset = null;try {connection = getConnection();statement = connection.createStatement();//创建SQL语句对象resultset = statement.executeQuery(sql);//执行SQL语句,此时用户数据都在resultset里面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);//释放资源}}/*** 查询用户数据** @author ZhaoZhengyi*/public void select(String sql,IRowMapper rowMapper,Object ...params) {Connection connection = null;PreparedStatement prepareStatement = null;ResultSet resultset = null;try {connection = getConnection();prepareStatement = connection.prepareStatement(sql);for (int i = 0; i < params.length; i++) {prepareStatement.setObject(i+1, params[i]);}resultset = prepareStatement.executeQuery();//执行SQL语句,此时用户数据都在resultset里面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,prepareStatement,connection);//释放资源}}/*** 释放资源** @author ZhaoZhengyi*/private void close(Statement statement,Connection connection) {try {if (statement != null) {//有可能由于异常导致statement没有赋值（譬如url出错），此时不必释放资源（多余），不然会报空指针异常statement.close();}} catch (SQLException e) {logger.debug(e.getMessage(), e);}try {if (connection != null) {connection.close();}} catch (SQLException e) {logger.debug(e.getMessage(), e);}}/*** 与上一方法是重载** @author ZhaoZhengyi*/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);}}

IRowMapper接口：

package com.zzu.tool.db;import java.sql.ResultSet;@FunctionalInterface
public interface IRowMapper {/*** 定义一个抽象方法（参数类型为ResultSet）** @author ZhaoZhengyi*/void rowMapper (ResultSet rs);
}

PropertiesTool类（获取数据库连接的桥梁）：

package com.zzu.tool;import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;public class PropertiesTool {private static Properties properties = new Properties();/*** 联系db.properties文件和properties* * 静态代码块先于main方法先执行*/static {InputStream inputStream = PropertiesTool.class.getClassLoader().getResourceAsStream("db.properties");//将db.properties变为javaIO流对传入到inputStream中//此时db.properties文件中的数据就保存到了inputStream中try {properties.load(inputStream);//将inputStream中的key和value放到load方法中进行解析再存到properties中} catch (IOException e) {e.printStackTrace();}}/*** 我们创建一个getVaule方法来便于调用文件（此时也就是properties）中的数据*/public static String getValue(String key) {return properties.getProperty(key);//返回properties中的key值}/*** 我们来测试一下：*/public static void main(String [] ages) {String userName = getValue("db.userName");String password = getValue("db.password");String url = getValue("db.url");String driver = getValue("db.driver");System.out.println(userName);System.out.println(password);System.out.println(url);System.out.println(driver);}
}

要使用的资源：

db.properties（连接数据库的一些必要信息）:

db.userName = root
db.password = root
db.url = jdbc:mysql://127.0.0.1:3306/test
db.driver = com.mysql.jdbc.Driver

log4j.properties（收集异常信息所需要的一些配置）:

# 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

slf4j-log4j：

# 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
#每天产生一个日志文件(RollingFile)  
log4j.appender.RollingFile=org.apache.log4j.DailyRollingFileAppender
#当天的日志文件全路径
log4j.appender.RollingFile.File=d:/logs/sirius.log
#服务器启动日志是追加，false：服务器启动后会生成日志文件把老的覆盖掉
log4j.appender.RollingFile.Append=true
#日志文件格式  
log4j.appender.RollingFile.layout=org.apache.log4j.PatternLayout  
log4j.appender.RollingFile.layout.ConversionPattern=%d [%t] %-5p %-40.40c %X{traceId}-%m%n
log4j.appender.RollingFile.Threshold=DEBUG
#设置每天生成一个文件名后添加的名称,备份名称：sirius.log.年月日时分.log
log4j.appender.RollingFile.DatePattern='.'yyyy-MM-dd-HH-mm'.log'