数据库操作疑难:Java连接MySQL并执行SQL语句
在Java中连接MySQL并执行SQL语句,通常会用到JDBC(Java Database Connectivity)API。以下是一个基本的步骤:
添加依赖:
- 如果你使用Maven作为构建工具,添加MySQL驱动到pom.xml文件:
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.24</version> <!-- 更新你的版本 -->
</dependency>
- 如果你使用Gradle,将依赖添加到build.gradle文件:
dependencies {
implementation 'mysql
8.0.24'
}
- 如果你使用Maven作为构建工具,添加MySQL驱动到pom.xml文件:
创建Java类:
创建一个Java类(比如DatabaseConnection
),并在其中编写方法来连接数据库和执行SQL语句。连接数据库:
在连接数据库的方法中,使用JDBC的DriverManager.getConnection()
方法连接MySQL:
import java.sql.Connection;
import java.sql.DriverManager;
public class DatabaseConnection {
private static final String DB_URL = "jdbc:mysql://localhost:3306/mydatabase";
private static final String USER = "username";
private static final String PASS = "password";
public Connection connect() {
Connection connection = null;
try {
// 注册JDBC驱动
Class.forName("com.mysql.cj.jdbc.Driver");
// 连接数据库
connection = DriverManager.getConnection(DB_URL, USER, PASS));
System.out.println("Database connected successfully!");
} catch (Exception e) {
System.out.println("Error occurred while connecting to the database: " + e.getMessage());
}
return connection;
}
}
- 执行SQL语句:
在连接数据库后,你可以创建一个方法来执行SQL语句。例如:
public void executeSql(String sql) {
try (Connection connection = connect()) {
if (connection != null) {
Statement statement = connection.createStatement();
int rowsAffected = statement.executeUpdate(sql);
System.out.println("Number of rows affected: " + rowsAffected);
} else {
System.out.println("Database connection is null. Unable to execute SQL.");
}
} catch (Exception e) {
System.out.println("Error occurred while executing SQL: " + e.getMessage());
}
}
现在你可以创建一个DatabaseConnection
对象,通过它来连接数据库并执行SQL语句。
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