day39-Spring 13-Spring的JDBC模板：默认连接池的配置

Spring内置的连接池DriverManagerDataSource的源码.

/*
 * Copyright 2002-2008 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jdbc.datasource;

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

import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;

/**
 * Simple implementation of the standard JDBC {@link javax.sql.DataSource} interface,
 * configuring the plain old JDBC {@link java.sql.DriverManager} via bean properties, and
 * returning a new {@link java.sql.Connection} from every <code>getConnection</code> call.
 *
 * <p><b>NOTE: This class is not an actual connection pool; it does not actually
 * pool Connections.</b> It just serves as simple replacement for a full-blown
 * connection pool, implementing the same standard interface, but creating new
 * Connections on every call.
 *
 * <p>Useful for test or standalone environments outside of a J2EE container, either
 * as a DataSource bean in a corresponding ApplicationContext or in conjunction with
 * a simple JNDI environment. Pool-assuming <code>Connection.close()</code> calls will
 * simply close the Connection, so any DataSource-aware persistence code should work.
 *
 * <p><b>NOTE: Within special class loading environments such as OSGi, this class
 * is effectively superseded by {@link SimpleDriverDataSource} due to general class
 * loading issues with the JDBC DriverManager that be resolved through direct Driver
 * usage (which is exactly what SimpleDriverDataSource does).</b>
 *
 * <p>In a J2EE container, it is recommended to use a JNDI DataSource provided by
 * the container. Such a DataSource can be exposed as a DataSource bean in a Spring
 * ApplicationContext via {@link org.springframework.jndi.JndiObjectFactoryBean},
 * for seamless switching to and from a local DataSource bean like this class.
 * For tests, you can then either set up a mock JNDI environment through Spring's
 * {@link org.springframework.mock.jndi.SimpleNamingContextBuilder}, or switch the
 * bean definition to a local DataSource (which is simpler and thus recommended).
 *
 * <p>If you need a "real" connection pool outside of a J2EE container, consider
 * <a href="http://jakarta.apache.org/commons/dbcp">Apache's Jakarta Commons DBCP</a>
 * or <a href="http://sourceforge.net/projects/c3p0">C3P0</a>.
 * Commons DBCP's BasicDataSource and C3P0's ComboPooledDataSource are full
 * connection pool beans, supporting the same basic properties as this class
 * plus specific settings (such as minimal/maximal pool size etc).
 *
 * @author Juergen Hoeller
 * @since 14.03.2003
 * @see SimpleDriverDataSource
 */
public class DriverManagerDataSource extends AbstractDriverBasedDataSource {

    /**
     * Constructor for bean-style configuration.
     */
    public DriverManagerDataSource() {
    }

    /**
     * Create a new DriverManagerDataSource with the given JDBC URL,
     * not specifying a username or password for JDBC access.
     * @param url the JDBC URL to use for accessing the DriverManager
     * @see java.sql.DriverManager#getConnection(String)
     */
    public DriverManagerDataSource(String url) {
        setUrl(url);
    }

    /**
     * Create a new DriverManagerDataSource with the given standard
     * DriverManager parameters.
     * @param url the JDBC URL to use for accessing the DriverManager
     * @param username the JDBC username to use for accessing the DriverManager
     * @param password the JDBC password to use for accessing the DriverManager
     * @see java.sql.DriverManager#getConnection(String, String, String)
     */
    public DriverManagerDataSource(String url, String username, String password) {
        setUrl(url);
        setUsername(username);
        setPassword(password);
    }

    /**
     * Create a new DriverManagerDataSource with the given JDBC URL,
     * not specifying a username or password for JDBC access.
     * @param url the JDBC URL to use for accessing the DriverManager
     * @param conProps JDBC connection properties
     * @see java.sql.DriverManager#getConnection(String)
     */
    public DriverManagerDataSource(String url, Properties conProps) {
        setUrl(url);
        setConnectionProperties(conProps);
    }

    /**
     * Create a new DriverManagerDataSource with the given standard
     * DriverManager parameters.
     * @param driverClassName the JDBC driver class name
     * @param url the JDBC URL to use for accessing the DriverManager
     * @param username the JDBC username to use for accessing the DriverManager
     * @param password the JDBC password to use for accessing the DriverManager
     * @deprecated since Spring 2.5. DriverManagerDataSource is primarily
     * intended for accessing <i>pre-registered</i> JDBC drivers.
     * If you need to register a new driver, consider using
     * {@link SimpleDriverDataSource} instead.
     */
    @Deprecated
    public DriverManagerDataSource(String driverClassName, String url, String username, String password) {
        setDriverClassName(driverClassName);
        setUrl(url);
        setUsername(username);
        setPassword(password);
    }

    /**
     * Set the JDBC driver class name. This driver will get initialized
     * on startup, registering itself with the JDK's DriverManager.
     * <p><b>NOTE: DriverManagerDataSource is primarily intended for accessing
     * <i>pre-registered</i> JDBC drivers.</b> If you need to register a new driver,
     * consider using {@link SimpleDriverDataSource} instead. Alternatively, consider
     * initializing the JDBC driver yourself before instantiating this DataSource.
     * The "driverClassName" property is mainly preserved for backwards compatibility,
     * as well as for migrating between Commons DBCP and this DataSource.
     * @see java.sql.DriverManager#registerDriver(java.sql.Driver)
     * @see SimpleDriverDataSource
     */
    public void setDriverClassName(String driverClassName) {
        Assert.hasText(driverClassName, "Property 'driverClassName' must not be empty");
        String driverClassNameToUse = driverClassName.trim();
        try {
            Class.forName(driverClassNameToUse, true, ClassUtils.getDefaultClassLoader());
        }
        catch (ClassNotFoundException ex) {
            throw new IllegalStateException("Could not load JDBC driver class [" + driverClassNameToUse + "]", ex);
        }
        if (logger.isInfoEnabled()) {
            logger.info("Loaded JDBC driver: " + driverClassNameToUse);
        }
    }

    @Override
    protected Connection getConnectionFromDriver(Properties props) throws SQLException {
        String url = getUrl();
        if (logger.isDebugEnabled()) {
            logger.debug("Creating new JDBC DriverManager Connection to [" + url + "]");
        }
        return getConnectionFromDriverManager(url, props);
    }

    /**
     * Getting a Connection using the nasty static from DriverManager is extracted
     * into a protected method to allow for easy unit testing.
     * @see java.sql.DriverManager#getConnection(String, java.util.Properties)
     */
    protected Connection getConnectionFromDriverManager(String url, Properties props) throws SQLException {
        return DriverManager.getConnection(url, props);
    }

}

DriverManagerDataSource的父类AbstractDriverBasedDataSource的源码
/*
 * Copyright 2002-2008 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jdbc.datasource;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

import org.springframework.util.Assert;

/**
 * Abstract base class for JDBC {@link javax.sql.DataSource} implementations
 * that operate on a JDBC {@link java.sql.Driver}.
 *
 * @author Juergen Hoeller
 * @since 2.5.5
 * @see SimpleDriverDataSource
 * @see DriverManagerDataSource
 */
public abstract class AbstractDriverBasedDataSource extends AbstractDataSource {

    private String url;

    private String username;

    private String password;

    private Properties connectionProperties;

    /**
     * Set the JDBC URL to use for connecting through the Driver.
     * @see java.sql.Driver#connect(String, java.util.Properties)
     */
    public void setUrl(String url) {
        Assert.hasText(url, "Property 'url' must not be empty");
        this.url = url.trim();
    }

    /**
     * Return the JDBC URL to use for connecting through the Driver.
     */
    public String getUrl() {
        return this.url;
    }

    /**
     * Set the JDBC username to use for connecting through the Driver.
     * @see java.sql.Driver#connect(String, java.util.Properties)
     */
    public void setUsername(String username) {
        this.username = username;
    }

    /**
     * Return the JDBC username to use for connecting through the Driver.
     */
    public String getUsername() {
        return this.username;
    }

    /**
     * Set the JDBC password to use for connecting through the Driver.
     * @see java.sql.Driver#connect(String, java.util.Properties)
     */
    public void setPassword(String password) {
        this.password = password;
    }

    /**
     * Return the JDBC password to use for connecting through the Driver.
     */
    public String getPassword() {
        return this.password;
    }

    /**
     * Specify arbitrary connection properties as key/value pairs,
     * to be passed to the Driver.
     * <p>Can also contain "user" and "password" properties. However,
     * any "username" and "password" bean properties specified on this
     * DataSource will override the corresponding connection properties.
     * @see java.sql.Driver#connect(String, java.util.Properties)
     */
    public void setConnectionProperties(Properties connectionProperties) {
        this.connectionProperties = connectionProperties;
    }

    /**
     * Return the connection properties to be passed to the Driver, if any.
     */
    public Properties getConnectionProperties() {
        return this.connectionProperties;
    }

    /**
     * This implementation delegates to <code>getConnectionFromDriver</code>,
     * using the default username and password of this DataSource.
     * @see #getConnectionFromDriver(String, String)
     * @see #setUsername
     * @see #setPassword
     */
    public Connection getConnection() throws SQLException {
        return getConnectionFromDriver(getUsername(), getPassword());
    }

    /**
     * This implementation delegates to <code>getConnectionFromDriver</code>,
     * using the given username and password.
     * @see #getConnectionFromDriver(String, String)
     */
    public Connection getConnection(String username, String password) throws SQLException {
        return getConnectionFromDriver(username, password);
    }

    /**
     * Build properties for the Driver, including the given username and password (if any),
     * and obtain a corresponding Connection.
     * @param username the name of the user
     * @param password the password to use
     * @return the obtained Connection
     * @throws SQLException in case of failure
     * @see java.sql.Driver#connect(String, java.util.Properties)
     */
    protected Connection getConnectionFromDriver(String username, String password) throws SQLException {
        Properties props = new Properties(getConnectionProperties());
        if (username != null) {
            props.setProperty("user", username);
        }
        if (password != null) {
            props.setProperty("password", password);
        }
        return getConnectionFromDriver(props);
    }

    /**
     * Obtain a Connection using the given properties.
     * <p>Template method to be implemented by subclasses.
     * @param props the merged connection properties
     * @return the obtained Connection
     * @throws SQLException in case of failure
     */
    protected abstract Connection getConnectionFromDriver(Properties props) throws SQLException;

}

---

    public void setDriverClassName(String driverClassName) {
        Assert.hasText(driverClassName, "Property 'driverClassName' must not be empty");
        String driverClassNameToUse = driverClassName.trim();
        try {

public abstract class AbstractDriverBasedDataSource extends AbstractDataSource {

    private String url;

    private String username;

    private String password;

    private Properties connectionProperties;

    <!-- 配置Spring默认的连接池 -->
    <!-- 这个类由Spring来帮我们创建,它默认情况下只创建一次,因为是单例的. -->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">

        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql:///spring3_day02"></property>
        <property name="username" value="root"></property>
        <property name="password" value="123"></property>

    </bean>
    <!-- 定义jdbctemplate -->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
          <property name="dataSource" ref="dataSource"></property><!-- 把上面定义好的连接池注入进来了 -->
    </bean>

---

7:26:03,403  INFO XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [applicationContext.xml]
17:26:03,514  INFO GenericApplicationContext:510 - Refreshing org.springframework.context.support.GenericApplicationContext@1fa78298: startup date [Fri May 05 17:26:03 CST 2017]; root of context hierarchy
17:26:03,595  INFO DefaultListableBeanFactory:577 - Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@63a52fe6: defining beans [dataSource,jdbcTemplate,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor]; root of factory hierarchy
17:26:03,633  INFO DriverManagerDataSource:153 - Loaded JDBC driver: com.mysql.jdbc.Driver
17:26:03,998  INFO GenericApplicationContext:1042 - Closing org.springframework.context.support.GenericApplicationContext@1fa78298: startup date [Fri May 05 17:26:03 CST 2017]; root of context hierarchy
17:26:03,999  INFO DefaultListableBeanFactory:444 - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@63a52fe6: defining beans [dataSource,jdbcTemplate,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor]; root of factory hierarchy

不会把SQL语句打印出来,因为它不是Hibernate.

---

package cn.itcast.spring3.demo1;

import java.sql.DriverManager;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.transaction.jta.SpringJtaSynchronizationAdapter;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class SpringTest1 {

    @Autowired
    @Qualifier("jdbcTemplate")
    private JdbcTemplate jdbcTemplate;//注入Jdbc模板
    @Test
    public void demo2(){
        jdbcTemplate.execute("create table user (id int primary key auto_increment,name varchar(20))");
    }

    @Test
    public void demo1(){
        // 创建连接池:
        DriverManagerDataSource dataSource = new DriverManagerDataSource();//Spring自带的连接池
        // 设置参数:
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql:///spring3_day02");
        dataSource.setUsername("root");
        dataSource.setPassword("");

        //使用JDBC的模板:
        //JdbcTemplate jdbcTemplate = new JdbcTemplate();
        //jdbcTemplate.setDataSource(dataSource);
        JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
        jdbcTemplate.execute("create table user (id int primary key auto_increment,name varchar(20))");
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<!-- 引入beans的头 -->
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    <!-- 配置Spring默认的连接池 -->
    <!-- 这个类由Spring来帮我们创建,它默认情况下只创建一次,因为是单例的. -->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">

        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql:///spring3_day02"></property>
        <property name="username" value="root"></property>
        <property name="password" value=""></property>

    </bean>
    <!-- 定义jdbctemplate -->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
          <property name="dataSource" ref="dataSource"></property><!-- 把上面定义好的连接池注入进来了 -->
    </bean>
</beans>

---

---