数据库操作常见问题：Java与MySQL等数据库连接和操作示例-蒲公英云

数据库操作常见问题：Java与MySQL等数据库连接和操作示例

原创 r囧r小猫 2024-09-18 10:45 146阅读 0赞

在Java中，我们通常使用JDBC（Java Database Connectivity）来连接和操作MySQL等数据库。以下是一个基本的连接和查询示例：

连接数据库：
```java
import java.sql.Connection;
import java.sql.DriverManager;

public class DatabaseConnection {
private static final String DB_URL = “jdbc//localhost:3306/mydatabase”;
private static final String USER = “username”;
private static final String PASS = “password”;

public static Connection connectToDB() {
    try {
        return DriverManager.getConnection(DB_URL, USER, PASS));
    } catch (Exception e) {
        System.out.println("Error while connecting to database: " + e.getMessage());
        e.printStackTrace();
        return null;
    }
}

}


2. **执行查询操作**：
```java
import java.sql.ResultSet;
import java.sql.Statement;
public class DatabaseQuery {
    public static void main(String[] args) {
        Connection conn = DatabaseConnection.connectToDB();
        if (conn != null) {
            try {
                // 创建Statement对象，用于执行SQL语句
                Statement stmt = conn.createStatement();
                // 执行查询语句（这里示例为：获取所有用户信息的SELECT语句） 
                ResultSet rs = stmt.executeQuery("SELECT * FROM users");
                // 遍历查询结果并打印
                while (rs.next()) {
                    System.out.println(rs.getString("username")) + " - " + rs.getString("email"));
                }
                rs.close();
                stmt.close();
            } catch (Exception e) {
                System.out.println("Error occurred while executing SQL query: " + e.getMessage());
                e.printStackTrace();
            }
        }
    }
}