JDBC增删改查代码实现 - 数据库操作教程 - 常规

以下是使用JDBC对数据库进行增删改查的具体代码实现。

导入JDBC相关的包：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

建立数据库连接：

public Connection getConnection() {
    Connection conn = null;
    try {
        // 加载驱动
        Class.forName('com.mysql.jdbc.Driver');
        // 建立连接
        conn = DriverManager.getConnection('jdbc:mysql://localhost:3306/mydatabase', 'username', 'password');
    } catch (ClassNotFoundException | SQLException e) {
        e.printStackTrace();
    }
    return conn;
}

// 示例代码中使用了MySQL数据库，需要下载MySQL的JDBC驱动并导入项目中。

插入数据：

public void insertData(String name, int age) {
    Connection conn = null;
    Statement stmt = null;
    try {
        conn = getConnection();
        stmt = conn.createStatement();
        String sql = "INSERT INTO student (name, age) VALUES ('" + name + "', " + age + ")";
        stmt.executeUpdate(sql);
    } catch (SQLException e) {
        e.printStackTrace();
    } finally {
        try {
            if (stmt != null)
                stmt.close();
            if (conn != null)
                conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

更新数据：

public void updateData(int id, String newName, int newAge) {
    Connection conn = null;
    Statement stmt = null;
    try {
        conn = getConnection();
        stmt = conn.createStatement();
        String sql = "UPDATE student SET name='" + newName + "', age=" + newAge + " WHERE id=" + id;
        stmt.executeUpdate(sql);
    } catch (SQLException e) {
        e.printStackTrace();
    } finally {
        try {
            if (stmt != null)
                stmt.close();
            if (conn != null)
                conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

删除数据：

public void deleteData(int id) {
    Connection conn = null;
    Statement stmt = null;
    try {
        conn = getConnection();
        stmt = conn.createStatement();
        String sql = "DELETE FROM student WHERE id=" + id;
        stmt.executeUpdate(sql);
    } catch (SQLException e) {
        e.printStackTrace();
    } finally {
        try {
            if (stmt != null)
                stmt.close();
            if (conn != null)
                conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

查询数据：

public void queryData() {
    Connection conn = null;
    Statement stmt = null;
    ResultSet rs = null;
    try {
        conn = getConnection();
        stmt = conn.createStatement();
        String sql = "SELECT * FROM student";
        rs = stmt.executeQuery(sql);
        while (rs.next()) {
            int id = rs.getInt('id');
            String name = rs.getString('name');
            int age = rs.getInt('age');
            System.out.println('ID: ' + id + ', Name: ' + name + ', Age: ' + age);
        }
    } catch (SQLException e) {
        e.printStackTrace();
    } finally {
        try {
            if (rs != null)
                rs.close();
            if (stmt != null)
                stmt.close();
            if (conn != null)
                conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

以上是使用JDBC对数据库进行增删改查的基本代码实现。需要根据实际情况修改数据库连接的URL、用户名和密码以及SQL语句中的表名和列名。同时需要注意对数据库连接、Statement、ResultSet等资源的正确关闭。