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");//name
		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 block
							e.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null
		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();//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null
		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();//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prepareStatement
			for(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;
	}
	
	
	
	/**
	 * 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();//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