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java如何连接sql数据库

2026-03-03 00:50:19Java

连接SQL数据库的方法

Java连接SQL数据库通常使用JDBC（Java Database Connectivity）技术。以下是几种常见数据库的连接方式。

连接MySQL数据库

确保已安装MySQL JDBC驱动（mysql-connector-java.jar），并将其添加到项目依赖中。

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

public class MySQLConnection {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/database_name";
        String username = "root";
        String password = "password";

        try {
            Connection connection = DriverManager.getConnection(url, username, password);
            System.out.println("Connected to MySQL database!");
            connection.close();
        } catch (SQLException e) {
            System.out.println("Connection failed!");
            e.printStackTrace();
        }
    }
}

连接PostgreSQL数据库

需要postgresql.jar驱动文件。

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

public class PostgreSQLConnection {
    public static void main(String[] args) {
        String url = "jdbc:postgresql://localhost:5432/database_name";
        String username = "postgres";
        String password = "password";

        try {
            Connection connection = DriverManager.getConnection(url, username, password);
            System.out.println("Connected to PostgreSQL database!");
            connection.close();
        } catch (SQLException e) {
            System.out.println("Connection failed!");
            e.printStackTrace();
        }
    }
}

连接SQL Server数据库

需要mssql-jdbc.jar驱动文件。

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

public class SQLServerConnection {
    public static void main(String[] args) {
        String url = "jdbc:sqlserver://localhost:1433;databaseName=database_name";
        String username = "sa";
        String password = "password";

        try {
            Connection connection = DriverManager.getConnection(url, username, password);
            System.out.println("Connected to SQL Server database!");
            connection.close();
        } catch (SQLException e) {
            System.out.println("Connection failed!");
            e.printStackTrace();
        }
    }
}

使用连接池提高性能

对于生产环境，建议使用连接池管理数据库连接。以下是使用HikariCP连接池的示例：

import com.zaxxer.hikari.HikariConfig;
import com.zaxxer.hikari.HikariDataSource;
import java.sql.Connection;
import java.sql.SQLException;

public class ConnectionPoolExample {
    public static void main(String[] args) {
        HikariConfig config = new HikariConfig();
        config.setJdbcUrl("jdbc:mysql://localhost:3306/database_name");
        config.setUsername("root");
        config.setPassword("password");
        config.addDataSourceProperty("cachePrepStmts", "true");
        config.addDataSourceProperty("prepStmtCacheSize", "250");
        config.addDataSourceProperty("prepStmtCacheSqlLimit", "2048");

        try (HikariDataSource ds = new HikariDataSource(config);
             Connection connection = ds.getConnection()) {
            System.out.println("Connection obtained from pool");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}