从控制台输入输出，来进行数据库的插入和查询操作的小程序

Posted 2020-08-06 Hello.World!

从控制台输入输出，来进行数据库的插入和查询操作的小程序（利用JDBC）

首先来看一下数据库结构

 

然后将数据库中插入如下数据

 

eclipse中包和Java文件

examStudent包的代码

ExamStudent.java

package examStudent;

public class ExamStudent {
    /**
     * 流水号
     */
    private int flowId;

    /**
     * 四级、六级
     */
    private int type;

    /**
     * 身份证号码
     */
    private int idCard;

    /**
     * 准考证号码
     */
    private int examCard;

    /**
     * 学生姓名
     */
    private String studentName;

    /**
     * 区域
     */
    private String location;

    /**
     * 成绩
     */
    private int grade;

    public int getFlowId() {
        return flowId;
    }

    public int getType() {
        return type;
    }

    public void setType(int type) {
        this.type = type;
    }

    public int getIdCard() {
        return idCard;
    }

    public void setIdCard(int idCard) {
        this.idCard = idCard;
    }

    public int getExamCard() {
        return examCard;
    }

    public void setExamCard(int examCard) {
        this.examCard = examCard;
    }

    public String getStudentName() {
        return studentName;
    }

    public void setStudentName(String studentName) {
        this.studentName = studentName;
    }

    public String getLocation() {
        return location;
    }

    public void setLocation(String location) {
        this.location = location;
    }

    public int getGrade() {
        return grade;
    }

    public void setGrade(int grade) {
        this.grade = grade;
    }
}

View Code

ExamStudentDao.java

package examStudent;

import java.util.List;
import java.util.Scanner;

import org.junit.Test;

import tools.SqlTools;

public class ExamStudentDao {
    /**
     * 插入一条数据
     */
    public void update() {
        ExamStudent examStudent = new ExamStudent();
        // 从控制台输入 Type,idCard,examCard,studentName,location,grade
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入考生的详细信息");
        System.out.print("Type: ");
        int type = sc.nextInt();
        System.out.print("IDCard: ");
        int idCard = sc.nextInt();
        System.out.print("ExamCard: ");
        int examCard = sc.nextInt();
        System.out.print("StudentName: ");
        String studentName = sc.next();
        System.out.print("Location: ");
        String location = sc.next();
        System.out.print("Grade: ");
        int grade = sc.nextInt();
        // 将从控制台输入的值分别写入ExamStudent中
        examStudent.setType(type);
        examStudent.setIdCard(idCard);
        examStudent.setExamCard(examCard);
        examStudent.setStudentName(studentName);
        examStudent.setLocation(location);
        examStudent.setGrade(grade);
        // sql文
        String sql = "INSERT INTO exam_student (TYPE,ID_CARD,EXAM_CARD,STUDENT_NAME,LOCATION,GRADE) VALUES (\'"
                + examStudent.getType() + "\',\'" + examStudent.getIdCard() + "\',\'" + examStudent.getExamCard() + "\',\'"
                + examStudent.getStudentName() + "\',\'" + examStudent.getLocation() + "\',\'" + examStudent.getGrade()
                + "\')";
        // 插入一条数据
        SqlTools.update(sql);
        System.out.println("插入成功");
    }

    /**
     * 根据身份证号码进行查询
     */
    public List findByIdCard(String idCard) {
        String sql = "SELECT * FROM EXAM_STUDENT WHERE ID_CARD=" + idCard;
        List list = SqlTools.findOne(sql);
        return list;
    }

    /**
     * 根据准考证号码进行查询
     */
    public List findByExamCard(String examCard) {
        String sql = "SELECT * FROM EXAM_STUDENT WHERE EXAM_CARD=" + examCard;
        List<ExamStudent> list = SqlTools.findOne(sql);
        return list;
    }
}

View Code

TestExamStudent.java

package examStudent;

import java.util.List;
import java.util.Scanner;

public class TestExamStudent {
    public static void main(String[] args) {
        ExamStudentDao esd = new ExamStudentDao();
        ExamStudent es = new ExamStudent();
        Scanner sc = new Scanner(System.in);
        System.out.println("输入1插入，输入2查询");
        int temp = sc.nextInt();
        if(temp == 1){
            esd.update();
        }else if(temp == 2){
            System.out.println("进入查询系统");
            System.out.println("请选择您要输入的类型：");
            System.out.println("3:准考证号");
            System.out.println("4:身份证号");
            int cardType = sc.nextInt();
            if(cardType == 3){
                System.out.println("请输入证件号码");
                String cardNum = sc.next();
                List list = esd.findByExamCard(cardNum);
                for (Object obj : list) {
                    System.out.println(obj);
                }
            }
            else if(cardType == 4){
                System.out.println("请输入证件号码");
                String cardNum = sc.next();
                List list = esd.findByIdCard(cardNum);
                if(list.isEmpty()){
                    System.out.println("查无此人");
                }else{
                    for (Object obj : list) {
                        System.out.println(obj);
                    }
                }
            }
            else{
                System.out.println("系统异常退出");
            }
        }else{
            System.out.println("系统退出");
        }
    }
}

View Code

Properties包下的properties文件

jdbcName.properties

jdbcName=mysql

View Code

mySql.properties

driver=com.mysql.jdbc.Driver
jdbcUrl=jdbc:mysql://localhost:3306/dic
user=root
password=123456

View Code

tools包下的Java代码

JDBCTools.java

package tools;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

/**
 * JDBC 的工具类
 */
public class JDBCTools {
    /**
     * 关闭ResultSet，Statement，Connection
     */
    public static void release(ResultSet rs, Statement statement, Connection connection) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (statement != null) {
            try {
                statement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 关闭Statement,Connection
     * 
     * @param statement
     * @param connection
     */
    public static void release(Statement statement, Connection connection) {
        if (statement != null) {
            try {
                statement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 获取数据库连接的方法
     * 
     * @return
     * @throws Exception
     */
    public static Connection getConnection() {
        // 准备连接数据库的四个字符串
        // 驱动的全类名
        String driverClass = null;
        String jdbcUrl = null;
        String user = null;
        String password = null;
        String jdbcName = null;
        // 读取jdbcName.properties文件
        InputStream inStream = JDBCTools.class.getClassLoader().getResourceAsStream("properties/jdbcName.properties");
        Properties propertiesOfName = new Properties();
        try {
            propertiesOfName.load(inStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
        jdbcName = propertiesOfName.getProperty("jdbcName");
        // 读取需要的properties 文件
        InputStream in = JDBCTools.class.getClassLoader().getResourceAsStream("properties/" + jdbcName + ".properties");
        Properties properties = new Properties();
        try {
            properties.load(in);
        } catch (IOException e) {
            e.printStackTrace();
        }
        driverClass = properties.getProperty("driver");
        jdbcUrl = properties.getProperty("jdbcUrl");
        user = properties.getProperty("user");
        password = properties.getProperty("password");
        // 加载数据库驱动程序(注册驱动)
        try {
            Class.forName(driverClass);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        Connection connection = null;
        try {
            connection = DriverManager.getConnection(jdbcUrl, user, password);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return connection;
    }
}

View Code

SqlTools.java

package tools;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class SqlTools {

    /**
     * 通用的更新方法：包括INSERT/UPDATE/DELETE
     * 
     * @param sql
     */
    public static void update(String sql) {
        Connection connection = null;
        Statement statement = null;
        try {
            connection = JDBCTools.getConnection();
            statement = connection.createStatement();
            statement.executeUpdate(sql);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            JDBCTools.release(statement, connection);
        }
    }

    /**
     * 通用的查询方法：SELECT
     */
    @SuppressWarnings({ "unchecked", "rawtypes" })
    public static List findOne(String sql) {
        Connection connection = null;
        Statement statement = null;
        ResultSet rs = null;
        try {
            // 1.获取Connection
            connection = JDBCTools.getConnection();
            // 2.获取Statement
            statement = connection.createStatement();
            // 4.执行查询，得到ResultSet
            rs = statement.executeQuery(sql);
            // 5.处理ResultSet
            List list = new ArrayList();
            ResultSetMetaData metaData = rs.getMetaData();
            int columnCount = metaData.getColumnCount();
            while (rs.next()) {
                Map rowData = new HashMap();
                for (int i = 1; i < columnCount; i++) {
                    rowData.put(metaData.getColumnName(i), rs.getObject(i));
                }
                list.add(rowData);
            }
            return list;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        } finally {
            // 6.关闭数据库相应的资源
            JDBCTools.release(rs, statement, connection);
        }
    }
}

View Code

注：1.记得要在lib目录下导入mySql的包，并add

　　2.入口在Test中，main方法

　　3.虽然此代码很low，但对于初学者理解还是很有帮助的，逻辑非常简单，但是这里会有冗余的代码，而且有很多地方需要更加优化，有待解决 // TODO

欢迎转载，转载请附此说明，谢谢。