Java之使用數據庫和Maven工具完成學生管理系統

項目框架結構

添加依賴

在pom.xml文件中添加依賴：

	<dependency>
	    <groupId>javax.servlet</groupId>
	    <artifactId>javax.servlet-api</artifactId>
	    <version>3.1.0</version>
	    <scope>provided</scope>
	</dependency>
	<dependency>
	    <groupId>log4j</groupId>
	    <artifactId>log4j</artifactId>
	    <version>1.2.17</version>
	</dependency>
	<dependency>
	    <groupId>mysql</groupId>
	    <artifactId>mysql-connector-java</artifactId>
	    <version>5.1.44</version>
	</dependency>

由此引入數據庫和log4j的jar包

Properties

db.properties：

db.username=root
db.password=root
db.url=jdbc:mysql://192.168.77.14/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=E://log.log
log4j.appender.RollingFile.layout=org.apache.log4j.PatternLayout
log4j.appender.RollingFile.layout.ConversionPattern=%d [%t] %-5p %-40.40c %X{traceId}-%m%n

寫出相應工具類

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");//將db.properties變爲javaIO流對象
    try {
      properties.load(inputStream);
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
  
  public static String getValue(String key) {
	  String value = properties.getProperty(key);
	  return value;
  }
}

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;

/**
 * 數據庫工具類
 * 
 * @author Administrator
 */
public class DBLink {
	
	private Logger logger = Logger.getLogger(DBLink.class);
	
	/**
	 * 獲取數據庫鏈接
	 * @return
	 */
	private Connection getConnection() {
		try {
			Class.forName("com.mysql.jdbc.Driver");//加載驅動
			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) {
			logger.debug(e.getMessage(), e);
		}
		return null;
	}
	
	/**
	 * 判斷sql語句是否存在數據
	 * @param sql
	 * @return
	 */
	public boolean exist(String sql) {
		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 {
			close(resultSet, statement, connection);
		}
		return false;
	}
	
	public boolean exist(String sql,Object ...params) {
		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();
			return resultSet.next();
		} catch (Exception e) {
			logger.debug(e.getMessage(), e);
		}finally {
			close(resultSet, preparedStatement, connection);
		}
		return false;
	}
	
	/**
	 * 查詢數據
	 * @param sql
	 * @param rowMapper
	 */
	public void select(String sql, IRowMapper rowMapper) {//接口無法創建對象，所以rowMapper參數一定指向IRowMapper接口實現類對象
		Connection connection = null;
		Statement statement = null;
		ResultSet resultSet = null;
		try {
			connection = getConnection();
			statement = connection.createStatement();
			resultSet = statement.executeQuery(sql);
			rowMapper.rowMapper(resultSet);
			
		} catch (Exception e) {
			logger.debug(e.getMessage(), e);
		}finally {
			close(resultSet, statement, connection);
		}
		
	}
	
	/**
	 * 查詢數據
	 * @param sql
	 * @param rowMapper
	 */
	public void select(String sql, IRowMapper rowMapper,Object ...params) {//接口無法創建對象，所以rowMapper參數一定指向IRowMapper接口實現類對象
		Connection connection = null;
		PreparedStatement preparedStatement = null;
		ResultSet resultSet = null;
		try {
			connection = getConnection();
			preparedStatement = connection.prepareStatement(sql);//含有?佔位符的sql
			for (int i = 0; i < params.length; i++) {
				preparedStatement.setObject(i + 1, params[i]);//爲?賦值
			}
			resultSet = preparedStatement.executeQuery();//執行sql
			rowMapper.rowMapper(resultSet);
		} catch (Exception e) {
			logger.debug(e.getMessage(), e);
		}finally {
			close(resultSet, preparedStatement, connection);
		}
		
	}

	/**
	 * 修改(insert、update、delete)數據
	 * @param sql
	 * @return
	 */
	public boolean update(String sql) {
		Connection connection = null;
		Statement statement = null;
		try {
			connection = getConnection();
			System.out.println(connection);
			statement = connection.createStatement();//獲取statement對象
			int result = statement.executeUpdate(sql);//執行sql語句，返回受影響的行數
			return result>0;
		} catch (Exception e) {
			logger.debug(e.getMessage(), e);
		}finally {
			close(statement, connection);
		}
		return false;
	}
	
	/**
	 * 修改(insert、update、delete)數據
	 * @param sql
	 * @return
	 */
	public boolean update(String sql,Object ...params) {
		Connection connection = null;
		PreparedStatement prepareStatement = null;
		try {
			connection = getConnection();
			prepareStatement = connection.prepareStatement(sql);
			for (int i = 0; i < params.length; i++) {
				prepareStatement.setObject(i+1, params[i]);//爲?賦值
			}
			return prepareStatement.executeUpdate()>0;
		} catch (Exception e) {
			logger.debug(e.getMessage(), e);
		}finally {
			close(prepareStatement, connection);
		}
		return false;
	}
	
	/**
	 * 釋放資源
	 * @param statement
	 * @param connection
	 */
	private void close(Statement statement,Connection connection) {
		try {
			if(statement!=null) {
				statement.close();
			}				
		} catch (SQLException e) {
			logger.debug(e.getMessage(), e);
		}
		try {
			if(connection!=null) {
				connection.close();					
			}
		} catch (SQLException e) {
			logger.debug(e.getMessage(), e);
		}
	}
	
	/**
	 * 釋放資源
	 * @param statement
	 * @param connection
	 */
	private void close(ResultSet resultSet,Statement statement,Connection connection) {
		try {
			if(resultSet!=null) {
				resultSet.close();			
			}
		} catch (SQLException e) {
			logger.debug(e.getMessage(), e);
		}
		try {
			if(statement!=null) {
				statement.close();
			}				
		} catch (SQLException e) {
			logger.debug(e.getMessage(), e);
		}
		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);
}

程序主體

package com.zzu.client;

import java.util.Scanner;

import com.zzu.tool.db.DBLink;

public class Main {
	
	private static DBLink db = new DBLink();

	public static void main(String[] args) {
		System.out.println("*********************************");
		System.out.println("*\t\t\t\t*");
		System.out.println("*\t歡迎使用學生信息管理系統\t*");
		System.out.println("*\t\t\t\t*");
		System.out.println("*********************************");
		while (true) {
			menu();
		}
	}

	static void menu() {
		System.out.println("1、添加學生信息");
		System.out.println("2、刪除學生信息");//學號
		System.out.println("3、修改學生信息");//地址傳遞
		System.out.println("4、查詢學生信息");//name
		System.out.println("請輸入操作，以Enter鍵結束:");
		Scanner scanner = new Scanner(System.in);
		int option  = scanner.nextInt();
		switch (option) {
			case 1:{
				System.out.println("請輸入學號：");
				String id = scanner.next();
				String sql = "select name from student where id=?";
				if(db.exist(sql, id)) {
					System.out.println("學號已存在，添加失敗！");
					return;
				}
				System.out.println("請輸入姓名：");
				String name = scanner.next();
				System.out.println("請輸入手機號：");
				String mobile = scanner.next();
				System.out.println("請輸入地址：");
				String address = scanner.next();
				sql = "insert into student (id,name,mobile,address) value(?,?,?,?)";
				if(db.update(sql, id,name,mobile,address)) {
					System.out.println("添加成功！");
					return;
				}
				System.out.println("添加失敗！");
				break;
			}
			case 2:{
				System.out.println("請輸入學號：");
				String id = scanner.next();
				String sql = "select name from student where id=?";
				if(!db.exist(sql, id)) {
					System.out.println("該學號不存在，刪除失敗！");
					return;
				}
				sql = "delete from student where id=?";
				if(db.update(sql, id)) {
					System.out.println("刪除成功！");
					return;
				}
				System.out.println("刪除失敗！");
				break;
			}
			case 3:{
				System.out.println("請輸入學號：");
				String id =scanner.next();
				String sql = "select name from student where id=?";
				if(!db.exist(sql, id)) {
					System.out.println("該學號不存在，修改失敗！");
					return;
				}
				System.out.println("請輸入新的姓名：");
				String name =scanner.next();
				System.out.println("請輸入新的手機號：");
				String mobile = scanner.next();
				System.out.println("請輸入新的地址：");
				String address = scanner.next();
				sql = "update student set name=?,mobile=?,address=? where id=?";
				if(db.update(sql,name,mobile,address,id)) {
					System.out.println("修改成功！");
					return;
				}
				System.out.println("修改失敗！");
				break;
			}
			case 4:{
				System.out.println("請輸入學號：");
				String id = scanner.next();
				String sql = "select name from student where id=?";
				if(!db.exist(sql,id)) {
					System.out.println("該學號不存在，查詢失敗！");
					return;
				}
				sql = "select id,name,mobile,address from student where id=?";
				//普通寫法
				/*class RowMapper implements 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="+id+" ,name="+name+" ,mobile="+mobile+" ,address="+address);
								return;
							}
							System.out.println("沒有找到該學號學生的信息");
						} catch (Exception e) {
							e.printStackTrace();
						}
					}
				}*/
				
				//Lambda表達式寫法
				/*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="+id+" ,name="+name+" ,mobile="+mobile+" ,address="+address);
							return;
						}
						System.out.println("沒有找到該學號學生的信息");
					} catch (Exception e) {
						e.printStackTrace();
					}
				};*/
				
				//最簡寫法
				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="+id+" ,name="+name+" ,mobile="+mobile+" ,address="+address);
							return;
						}
						System.out.println("沒有找到該學號學生的信息");
					} catch (Exception e) {
						e.printStackTrace();
					}
				}, id);
				break;
			}
			default:
				System.out.println("I'm Sorry,there is not the "+option+" option,please try again.");
		}
	}
}