maven与数据库实现学生管理系统

    技术2023-05-14  87

    结构:

    Main:

    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(); DBLink dblink = new DBLink(); switch (option) { case 1:{ System.out.println("请输入学号:"); String id = scanner.next(); 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("请输入地址:"); String address = scanner.next(); String sql = "select id from user_info where id=?"; if(dblink.exist(sql, id)) { System.out.println("学号已存在"); return; } sql = "insert into user_info (id,name,mobile,address) values (?,?,?,?)"; if(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("请输入学号:"); String id = scanner.next(); String sql = "select id from user_info where id =?"; if(!dblink.exist(sql,id)) { System.out.println("学号不存在"); return; } sql = "delete from user_info where id=?"; if(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("请输入学号:"); String id = scanner.next(); String sql = "select id from user_info where id =?"; if(!dblink.exist(sql,id)) { System.out.println("学号不存在"); return; } System.out.println("请输入新姓名:"); String name = scanner.next(); System.out.println("请输入新手机号:"); String mobile = scanner.next(); System.out.println("请输入新地址:"); String address = scanner.next(); sql = "update user_info set name=? , mobile =? ,address =? where id ='"+id+"'"; if(dblink.update(sql, name,mobile,address)) { System.out.println("修改成功!"); return; } System.out.println("修改失败"); break; } case 4:{ System.out.println("请输入学号:"); final String id = scanner.next(); String sql = "select id from user_info where id=?"; if(!dblink.exist(sql,id)) { System.out.println("学号不存在!"); return; } /*IRowMapper rowMapper = new IRowMapper() { public void rowMapper(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); } } catch (SQLException e) { e.printStackTrace(); } } }; sql = "select id,name,mobile,address from user_info where id =?"; dblink.select(sql,rowMapper,id);*/ //匿名内部类对象实现接口抽象方法 /*IRowMapper rowMapper = (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); } } catch (SQLException e) { e.printStackTrace(); } }; sql = "select id,name,mobile,address from user_info where id =?"; dblink.select(sql,rowMapper,id);*/ //lambda表达式实现接口抽象方法 sql = "select id,name,mobile,address from user_info where id =?"; DBLink.select(sql,(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); } } catch (SQLException e) { e.printStackTrace(); } },id); //进一步简化 break; } default: System.out.println("I'm Sorry,there is not the "+option+" option,please try again."); } } }

    DBLink:

    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 心游 */ public class DBLink { private static Logger logger = Logger.getLogger(DBLink.class); /** * 获取连接 * * @author 心游 */ public static Connection getConnection() {//增删改查都需要进行这一步骤,这可以简化代码 try { Class.forName("com.mysql.jdbc.Driver");//加载驱动 String url = PropertiesTool.getVaule("db.url"); String userName = PropertiesTool.getVaule("db.username"); String password = PropertiesTool.getVaule("db.password"); return DriverManager.getConnection(url, userName, password);//获取连接,产生每一个对象代表一次数据库连接 } catch (Exception e) { logger.debug(e.getMessage(),e); } return null; } /** * 修改(delete,update,insert)数据 * * @author 心游 */ public boolean update(String sql) { Connection connection =null; Statement statement = null; try { connection = getConnection(); System.out.println(connection); statement = connection.createStatement();//获取statement对象 int affect = statement.executeUpdate(sql);//执行sql语句,返回影响行数 if(affect>0) { System.out.println("OK"); }else System.out.println("NO"); 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(); return affect>0; } catch (Exception e) { logger.debug(e.getMessage(),e); }finally { close(statement,connection); } return false; } /** * 修改(delete,update,insert)数据 * * @author 心游 */ public static boolean update(String sql ,Object ...pramas) {//与上面的不同之处:可以处理这样的形式String where = "123 'or' 1 '=' 1"; Connection connection =null; PreparedStatement preparedStatement = null; try { connection = getConnection(); preparedStatement = connection.prepareStatement(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; } /** * 查找数据 * * @author 心游 */ public static void select(String sql,IRowMapper rowMapper,Object ...pramas) { Connection connection = null; PreparedStatement preparedStatement =null; ResultSet resultSet=null; try { connection = getConnection();//获取连接 preparedStatement = connection.prepareStatement(sql); for (int i = 0; i < pramas.length; i++) { preparedStatement.setObject(i+1,pramas[i]);//为?赋值 } resultSet= preparedStatement.executeQuery();//执行sql语句 rowMapper.rowMapper(resultSet); } catch (Exception e) { logger.debug(e.getMessage(),e); }finally { close(preparedStatement,connection,resultSet); } } /** * 判断SQL语句是否能查出数据 * * @author 心游 */ public static 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 Connection connection = null; Statement statement =null; ResultSet resultSet=null; try { connection = getConnection(); statement = connection.createStatement(); resultSet= statement.executeQuery(sql);//执行sql,将查询的数据存到ResultSet类型的变量中 return resultSet.next(); } catch (Exception e) { logger.debug(e.getMessage(),e); }finally { close(statement,connection,resultSet); } return false; } /** * 判断SQL语句是否能查出数据 * * @author 心游 */ public static boolean exist(String sql,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(); preparedStatement = connection.prepareStatement(sql); for (int i = 0; i < params.length; i++) { preparedStatement.setObject(i+1, params[i]); } resultSet= preparedStatement.executeQuery();//执行sql,将查询的数据存到ResultSet类型的变量中 return resultSet.next(); } catch (Exception e) { logger.debug(e.getMessage(),e); }finally { close(preparedStatement,connection,resultSet); } return false; } /** * 释放内存 * * @author 心游 */ 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); } } /** * 释放内存 * * @author 心游 */ private static void close(Statement statement,Connection connection,ResultSet resultSet) { try { if(resultSet!=null) { resultSet.close(); } } catch (SQLException e) { e.printStackTrace(); } 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); } } }

    IRowMapper:

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

    PropertiesTool:

    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 getVaule(String key) { return properties.getProperty(key); } public static void main(String [] args) { } }

    db.properties:

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

    log4.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

    pom.xml:

    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.jd</groupId> <artifactId>sirius</artifactId> <packaging>war</packaging> <version>0.0.1-SNAPSHOT</version> <name>sirius Maven Webapp</name> <url>http://maven.apache.org</url> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.47</version> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </dependency> <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api --> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>3.1.0</version> <scope>provided</scope> </dependency> </dependencies> <build> <finalName>sirius</finalName> </build> <profiles> <profile> <id>jdk1.8</id> <activation> <activeByDefault>true</activeByDefault> <jdk>1.8</jdk> </activation> <properties> <maven.compiler.source>1.8</maven.compiler.source> <maven.compiler.target>1.8</maven.compiler.target> <maven.compiler.compilerVersion>1.8</maven.compiler.compilerVersion> </properties> </profile> </profiles> </project>
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