Java连接数据库：异常处理与优化-蒲公英云

Java连接数据库：异常处理与优化

在Java中，连接数据库主要使用JDBC（Java Database Connectivity）接口。以下是一个简单的示例，包括异常处理和优化：

异常处理：
```java
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

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

public static Connection getConnection() throws SQLException {
    Connection connection = null;
    try {
        // 注册JDBC驱动
        Class.forName("com.mysql.jdbc.Driver");
        // 建立连接
        connection = DriverManager.getConnection(DB_URL, USER, PASSWORD));
        if (connection != null) {
            System.out.println("Database connection successful.");
        }
    } catch (Exception e) {
        System.err.println("Error occurred while connecting to database: " + e.getMessage());
        if (connection != null) {
            connection.close();
        }
        throw new SQLException(e.getMessage(), e));
    }
    return connection;
}
// 优化：使用连接池
private static final Object POOL_LOCK = new Object();
private static ConnectionPool getConnectionPool() throws SQLException {
    ConnectionPool pool = null;
    synchronized (POOL_LOCK) {
        if (pool == null) {
            // 初始化连接池
            pool = new SimpleConnectionPool();
        }
    }
    return pool.getConnection();
}
public static void main(String[] args) {
    try {
        // 使用优化后的连接池
        Connection connection = getConnectionPool().getConnection();
        if (connection != null) {
            System.out.println("Database connection successful.");
            // 处理数据库操作...
        } else {
            System.out.println("Connection to database pool failed.");
        }
    } catch (SQLException e) {
        System.err.println("Error occurred while connecting to database: " + e.getMessage());
        if (connection != null) {
            connection.close();
        }
        throw new RuntimeException(e.getMessage(), e));
    }
}