javajdbc实现学生管理系统增删改查

Java JDBC是Java语言中用于连接和操作关系型数据库的API，可以通过它实现学生管理系统的增删改查功能。以下是一个简单的示例代码，演示如何使用Java JDBC实现学生管理系统的增删改查功能：

1.导入JDBC的jar包，连接数据库

Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "123456");

2.实现查询功能

public void query() {
    Statement stmt = null;
    ResultSet rs = null;
    try {
        stmt = conn.createStatement();
        String sql = "select * from student";
        rs = stmt.executeQuery(sql);
        while (rs.next()) {
            System.out.println("id=" + rs.getInt("id") + ", name=" + rs.getString("name") + ", age=" + rs.getInt("age"));
        }
    } catch (SQLException e) {
        e.printStackTrace();
    } finally {
        try {
            if (rs != null) rs.close();
            if (stmt != null) stmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

3.实现添加功能

public void add(Student student) {
    PreparedStatement pstmt = null;
    try {
        String sql = "insert into student(name, age) values(?, ?)";
        pstmt = conn.prepareStatement(sql);
        pstmt.setString(1, student.getName());
        pstmt.setInt(2, student.getAge());
        pstmt.executeUpdate();
    } catch (SQLException e) {
        e.printStackTrace();
    } finally {
        try {
            if (pstmt != null) pstmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

4.实现删除功能

public void delete(int id) {
    PreparedStatement pstmt = null;
    try {
        String sql = "delete from student where id=?";
        pstmt = conn.prepareStatement(sql);
        pstmt.setInt(1, id);
        pstmt.executeUpdate();
    } catch (SQLException e) {
        e.printStackTrace();
    } finally {
        try {
            if (pstmt != null) pstmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

5.实现修改功能

public void update(Student student) {
    PreparedStatement pstmt = null;
    try {
        String sql = "update student set name=?, age=? where id=?";
        pstmt = conn.prepareStatement(sql);
        pstmt.setString(1, student.getName());
        pstmt.setInt(2, student.getAge());
        pstmt.setInt(3, student.getId());
        pstmt.executeUpdate();
    } catch (SQLException e) {
        e.printStackTrace();
    } finally {
        try {
            if (pstmt != null) pstmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

完整代码如下：

import java.sql.*;

public class StudentManager {

    private Connection conn;

    public StudentManager() {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "123456");
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }
    }

    public void query() {
        Statement stmt = null;
        ResultSet rs = null;
        try {
            stmt = conn.createStatement();
            String sql = "select * from student";
            rs = stmt.executeQuery(sql);
            while (rs.next()) {
                System.out.println("id=" + rs.getInt("id") + ", name=" + rs.getString("name") + ", age=" + rs.getInt("age"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) rs.close();
                if (stmt != null) stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    public void add(Student student) {
        PreparedStatement pstmt = null;
        try {
            String sql = "insert into student(name, age) values(?, ?)";
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, student.getName());
            pstmt.setInt(2, student.getAge());
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (pstmt != null) pstmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    public void delete(int id) {
        PreparedStatement pstmt = null;
        try {
            String sql = "delete from student where id=?";
            pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1, id);
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (pstmt != null) pstmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    public void update(Student student) {
        PreparedStatement pstmt = null;
        try {
            String sql = "update student set name=?, age=? where id=?";
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, student.getName());
            pstmt.setInt(2, student.getAge());
            pstmt.setInt(3, student.getId());
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (pstmt != null) pstmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        StudentManager manager = new StudentManager();
        manager.query();
        manager.add(new Student("Tom", 18));
        manager.query();
        manager.update(new Student(1, "Jack", 20));
        manager.query();
        manager.delete(2);
        manager.query();
    }
}

class Student {
    private int id;
    private String name;
    private int age;

    public Student(int id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

在本示例中，我们创建了一个StudentManager类，用于连接数据库和实现学生管理系统的增删改查功能。在main方法中，我们先查询了数据库中的学生信息，然后添加了一个新的学生，更新了一个学生的信息，删除了一个学生，最后再次查询了数据库中的学生信息，从而演示了增删改查功能的实现。