项目结构

Main.java

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学生管理系统\t*");System.out.println("*\t\t\t\t*");System.out.println("*********************************");while (true) {menu();}}static void menu() {//DBLink db = new DBLink();System.out.println("1添加学生信息");System.out.println("2修改学生信息");System.out.println("3查询学生信息");//地址传递System.out.println("4删除学生信息");//nameSystem.out.println("请输入Enter键以继续");final Scanner scanner = new Scanner(System.in);int option  = scanner.nextInt();switch (option) {case 1:{System.out.println("添加系统");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，添加失败");return;}System.out.println("请输入姓名");String name = scanner.next();System.out.println("请输入电话");String mobile = scanner.next();System.out.println("请输入地址");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");break;}System.out.println("添加失败");break;}case 2:{System.out.println("修改系统");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("请输入新姓名");String name = scanner.next();System.out.println("请输入新电话");String mobile = scanner.next();System.out.println("请输入新地址");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");break;}}System.out.println("没有找到学号为"+id+"的学生,请检查学号是否错误");break;}case 3:{System.out.println("欢迎使用查询系统");System.out.println("请输入学号");String id = scanner.next();String sql = "select id,name,mobile,address from student where id = ?";class RowMapper implements IRowMapper{public void IRowMapper(ResultSet rs) {try {if(rs.next()) {String name = rs.getString("name");String mobile = rs.getString("mobile");String address = rs.getString("address");System.out.println(id+","+name+","+mobile+","+address);return;}System.out.println("没有找到学生信息");} catch (SQLException e) {e.printStackTrace();}}}IRowMapper rowMapper = new RowMapper();new DBLink().select(sql,rowMapper,id);/*IRowMapper rowMapper = (rs)->{try {if(rs.next()) {String name = rs.getString("name");String mobile = rs.getString("mobile");String address = rs.getString("address");System.out.println(id+","+name+","+mobile+","+address);return;}System.out.println("没有找到学生信息");} catch (SQLException e) {e.printStackTrace();}};*//*db.select(sql, (rs)->{try {if(rs.next()) {String name = rs.getString("name");String mobile = rs.getString("mobile");String address = rs.getString("address");System.out.println(id+","+name+","+mobile+","+address);return;}System.out.println("没有找到学生信息");} catch (SQLException e) {e.printStackTrace();}}, id);*/break;}case 4:{System.out.println("欢迎使用删除系统");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)) {sql = "delete from student where id = ?";new DBLink().update(sql,id);System.out.println("删除成功");break;}System.out.println("未找到学号为'"+id+"'的学生,删除失败");break;}default:System.out.println("I'm Sorry,there is not the "+option+" option,please try again.");}}
}

Tool

DBLink.java

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;/*** 数据库管理工具类* * @author Administrator*/
public class DBLink {private Logger logger = Logger.getLogger(DBLink.class);/*** 获取数据库连接** @author Administrator*/private  Connection getConnection() {try {Class.forName("com.mysql.jdbc.Driver");//加载驱动String userName = PropertiesTool.getvalue("db.username");String password = PropertiesTool.getvalue("db.password");String url = PropertiesTool.getvalue("db.url");return DriverManager.getConnection(url, userName, password);//创建连接} catch (Exception e) {logger.debug(e.getMessage(), e);}return null;}/*** 查询数据** @author Administrator*/public void select(String sql,IRowMapper rowMapper,Object...params) {//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Connection connection = null;PreparedStatement preparedStatement = null;ResultSet resultSet =  null;try {	connection = getConnection();//创建连接preparedStatement = connection.prepareStatement(sql);//创建语句for (int i = 0; i < params.length; i++) {preparedStatement.setObject(i+1, params[i]);}resultSet = preparedStatement.executeQuery();//executeQuery()方法会把数据库响应的查询结果存放在ResultSet类对象中供我们使用rowMapper.IRowMapper(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);}}/*** 修改（insert，update和delete）数据** @author Administrator*/public boolean update(String sql) {Connection connection = null;//提升作用域Statement statement = null;try {connection = getConnection();statement = connection.createStatement();int result = statement.executeUpdate(sql);//执行SQL语句，返回受影响的语句行数//statement.close();//如果前面代码出错，下面代码将会不执行，所以不能写在这里//connection.close();return result>0;} catch (Exception e) {logger.debug(e.getMessage(), e);}finally {close(statement,connection);}return false;}/*** 修改（insert，update和delete）数据** @author Administrator*/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;}/*** 判断SQL语句是否能查出数据** @author Administrator*/public boolean exist(String sql,Object...params) {//查询Connection connection = null;PreparedStatement preparedStatement = null;ResultSet resultSet =  null;try {	connection = getConnection();//获取连接preparedStatement = connection.prepareStatement(sql);//创建语句for (int i = 0; i < params.length; i++) {preparedStatement.setObject(i+1, params[i]);//为占位符传值}resultSet = preparedStatement.executeQuery();return resultSet.next();//判断是否有值} catch (Exception e) {logger.debug(e.getMessage(), e);}finally {close(resultSet,preparedStatement,connection);}return false;}/*** 释放资源** @author Administrator*/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) {e.printStackTrace();}}/*** 释放资源** @author Administrator*/private void close(ResultSet resultSet,Statement statement,Connection connection) {//方法的重载try {if(resultSet!=null) {resultSet.close();}} catch (SQLException e) {e.printStackTrace();}close(statement,connection);}}

IRowMapper.java

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

Properties.java

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();static {InputStream inputStream = PropertiesTool.class.getClassLoader().getResourceAsStream("db.properties");//将db.properties变为javaIO流对象try {properties.load(inputStream);} catch (IOException e) {e.printStackTrace();}}public static String getvalue(String key) {return properties.getProperty(key);}}

Properties

db.properties

db.username=root
db.password=root
db.url=jdbc:mysql://localhost: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=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

jar包

1、junit

<dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>3.8.1</version><scope>test</scope>
</dependency>

2、javax.servlet

    <dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>3.1.0</version><scope>provided</scope></dependency>

3、mysql

	<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.42</version></dependency>

4、log4j

	<dependency><groupId>log4j</groupId><artifactId>log4j</artifactId><version>1.2.17</version></dependency>