Java 连接 MySQL 数据库方法

1、传统的连接方式

• 导入mysql-connector-java-x.x.x-bin.jar驱动包，也可以参考 https://blog.csdn.net/github_38336924/article/details/82352869 文章

• 注册驱动

// 动态加载mysql驱动
Class.forName("com.mysql.jdbc.Driver");

• 获取连接

String url = "jdbc:mysql://localhost:3306/mypro";
 
String user = "dadeity";
 
String password = "*****";
 
Connection conn = DriverManager.getConnection(url, user, password);

• Code

public static Connection getConnection() throws ClassNotFoundException {
        String url="jdbc:mysql://192.168.137.142:3306/mypro";
        String user="dadeity";
        String password="*****";
        String driverClass="com.mysql.jdbc.Driver";
        Connection con=null;
        Class.forName(driverClass);
        try {
            con=DriverManager.getConnection(url, user, password);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return con;
    }

2、读取配置文件方式

• 在 src 目录下创建一个以 .properties结尾的配置文件，内容如下

driver:com.mysql.jdbc.Driver
url:jdbc:mysql://192.168.137.142:3306/mypro
user:dadeity
password:****

• 读取配置文件

InputStream inputStream = DemoTwo.class.getClassLoader().getResourceAsStream("db.properties");

• 创建Properties对象

Properties pro = new Properties();

• 装载

pro.load(inputStream);

• 解析

String driver = pro.getProperty("driver");
String url = pro.getProperty("url");
String user = pro.getProperty("user");
String password = pro.getProperty("password");

• 注册驱动获取连接

Class.forName(driver);
Connection conn = DriverManager.getConnection(url, user, password);

• Code

public static Connection getConnection() throws IOException, ClassNotFoundException {
        // 读取类路径下的jdbc.propreties文件(配置文件)
        InputStream inputStream = DemoTwo.class.getClassLoader().getResourceAsStream("db.properties");
        // 创建 Properties 对象
        Properties pro = new Properties();
        // 装载
        pro.load(inputStream);
        // 解析
        String driver = pro.getProperty("driver");
        String url = pro.getProperty("url");
        String user = pro.getProperty("user");
        String password = pro.getProperty("password");

        Connection conn = null;
        // 注册驱动获取连接
        Class.forName(driver);
        try {
            conn = DriverManager.getConnection(url, user, password);

        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return conn;
    }

3、c3p0连接池连接数据库

所需的jar包：c3p0-0.9.2.1.jar，mchange-commons-java-0.2.3.4.jar，mysql-connector-java-5.1.40-bin.jar

• 下载并导入
  c3p0-*.jar下载地址 http://www.java2s.com/Code/Jar/c/Downloadc3p00921jar.html
  mchange-commons-java-*.jar下载地址http://www.java2s.com/Code/Jar/m/Downloadmchangecommonsjava0234jar.htm

• 在src目录下新建c3p0-config.xml文件，内容如下：

<c3p0-config>
    <named-config name="helloc3p0">
        
        <property name="user">dadeityproperty>
        <property name="password">*****property>
        <property name="driverClass">com.mysql.jdbc.Driverproperty>
        <property name="jdbcUrl">jdbc:mysql://192.168.137.142/myproproperty>

        
        <property name="acquireIncrement">5property>
        
        <property name="initialPoolSize">5property>
        
        <property name="minPoolSize">5property>
        
        <property name="maxPoolSize">10property>
        
        <property name="maxStatements">20property>
        
        <property name="maxStatementsPerConnection">5property>
    named-config>
c3p0-config>

• 获取连接Code

// 定义全局变量
private static ComboPooledDataSource ds;
// 静态代码块，命名配置
static {
	ds = new ComboPooledDataSource("helloc3p0");
}
// 获取数据源
public static DataSource getDataSource() {
	return ds;
}
// 获取连接
public static Connection getConnection() throws SQLException {
	return ds.getConnection();
}

4、数据库连接池

所需的jar包：commons-dbcp2-2.5.0.jar和相关的jar包

• 下载
  commons-dbcp2-*.jar下载地址 http://www-eu.apache.org/dist//commons/dbcp/binaries/commons-dbcp2-2.5.0-bin.tar.gz

• 创建基础数据源

BasicDataSource bs=new BasicDataSource();

• 设置属性

bs.setDriverClassName("com.mysql.jdbc.Driver");
bs.setUrl("jdbc:mysql://192.168.137.142:3306/mypro");
bs.setUsername("dadeity");
bs.setPassword("*****");

• Code

public static BasicDataSource getBasicDataSource(){
	// 实例化BasicDataSource
	BasicDataSource bs=new BasicDataSource();

	// 设置BasicDataSource属性
	// 设置四个属性
	bs.setDriverClassName("com.mysql.jdbc.Driver");
	bs.setUrl("jdbc:mysql://192.168.137.142:3306/mypro");
	bs.setUsername("dadeity");
	bs.setPassword("*****");
	return bs;
}