数据库连接池技术

//方法一，通过字符串来设置连接参数
public class JDBCUtil1 {
    private static BasicDataSource ds = null;
    private static String url="jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8";
    private static String user="root";
    private static String password="123123";
    private static String driverClass="com.mysql.jdbc.Driver";
    static{
        ds = new BasicDataSource();
        //最基本的链接配置
        ds.setUrl(url);
        ds.setUsername(user);
        ds.setPassword(password);
        ds.setDriverClassName(driverClass);
        
        //初始化连接数
        ds.setInitialSize(5);
        //最大连接数
        ds.setMaxActive(10);
        //最大等待时间
        ds.setMaxWait(3000);
    }
    
    public static Connection getConnection(){
        try {
            return ds.getConnection();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }
    
}

//方法二通过配置文件读取连接参数
public class JDBCUtil {
    private static BasicDataSource ds = null;
    static{
        //properties中的key不能乱写
        //通过BasicDataSource的set方法来得到key的写法，去掉set，首字母小写即可。
        Properties prop = new Properties();
　　　　　//读取配置文件，配置文件在下面　
        InputStream inputStream = JDBCUtil.class.getResourceAsStream("/db.properties");
        try {
            prop.load(inputStream);
            ds = (BasicDataSource) BasicDataSourceFactory.createDataSource(prop);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    public static Connection getConnection(){
        try {
            return ds.getConnection();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }
}

配置文件名db.properties

url=jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8
username=root
password=123123
driverClassName=com.mysql.jdbc.Driver
initialSize=5
maxActive=10
maxWait=3000

C3P0配置数据库连接池，需要导入c3p0-0.9.5.2.jar和mchange-commons-java-0.2.11.jar

配置方式一：

public class JDBCUtil1 {
    
    private static ComboPooledDataSource ds = null;
    
    private static String url="jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8";
    private static String user="root";
    private static String password="123123";
    private static String driverClass="com.mysql.jdbc.Driver";
    
    static{
        ds = new ComboPooledDataSource();
        //基本配置
        ds.setJdbcUrl(url);
        ds.setUser(user);
        ds.setPassword(password);
        try {
            ds.setDriverClass(driverClass);
        } catch (PropertyVetoException e) {
            e.printStackTrace();
        }
        
        ds.setInitialPoolSize(5);
        ds.setMaxPoolSize(10);
        //设置超时时间
        ds.setCheckoutTimeout(3000);
    }
    
    public static Connection getConnection(){
        try {
            return ds.getConnection();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }
    

}

配置方式二：通过读取配置文件c3p0-config.xml，配置文件必须命名唯一，只能叫c3p0-config.xml

配置文件信息

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
    <!-- 默认配置 -->
    <default-config>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/test</property>
        <property name="user">root</property>
        <property name="password">123123</property>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="initialPoolSize">5</property>
        <property name="maxPoolSize">10</property>
        <property name="checkoutTimeout">3000</property>
    </default-config>
    
    <!--  -->
    <named-config name="intergalactoApp">
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/test</property>
        <property name="user">root</property>
        <property name="password">123123</property>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="initialPoolSize">10</property>
        <property name="maxPoolSize">20</property>
        <property name="checkoutTimeout">5000</property>
    </named-config>
</c3p0-config>

代码示范

public class JDBCUtil {
    private static ComboPooledDataSource ds = null;
    static {
        // 读取的是default-config
        // ds = new ComboPooledDataSource();
        // 读取的是<named-config name="intergalactoApp">
        ds = new ComboPooledDataSource("intergalactoApp");
    }

    public static Connection getConnection() {
        try {
            return ds.getConnection();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

}

数据库连接池技术

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