Spring入门学习（外部属性文件） 第七节

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/u011171125/article/details/85224677

外部属性文件

导入连接数据库相应的jar包

1. 添加相应的包

   <!-- https://mvnrepository.com/artifact/com.mchange/c3p0 -->
   <dependency>
       <groupId>com.mchange</groupId>
       <artifactId>c3p0</artifactId>
       <version>0.9.5.2</version>
   </dependency>
     	
   <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
   <dependency>
       <groupId>mysql</groupId>
       <artifactId>mysql-connector-java</artifactId>
       <version>5.1.40</version>
   </dependency>
   

创建Spring配置文件

1. 创建beans-properties.xml配置文件
   以前使用这种方式配置数据源，但这种方式比较混杂，不利于人员寻找修改，所以引入了外部属性配置文件

   <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
   	<property name="user" value="root"></property>
   	<property name="password" value="zwf1233"></property>
   	<property name="driverClass" value="com.mysql.jdbc.Driver"></property>
   	<property name="jdbcUrl" value="jdbc:mysql://localhost:3306/test"></property>
   </bean>
   

2. 我们创建一个db.properties的配置文件

   user=root
   password=zwf1233
   driverClass=com.mysql.jdbc.Driver
   jdbcUrl=jdbc:mysql://localhost:3306/test
   

3. 修改Spring配置文件beans-properties.xml
   使用context:property-placeholder导入配置文件，以${xxx}的方式加载外部配置文件中的属性值。

   <!-- 导入属性文件 -->
   <context:property-placeholder location="classpath*:db.properties"/>
   
   <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
   	<property name="user" value="${user}"></property>
   	<property name="password" value="${password}"></property>
   	<property name="driverClass" value="${driverClass}"></property>
   	<property name="jdbcUrl" value="${jdbcUrl}"></property>
   </bean>
   

4. 创建测试类：

   	@Test
   	public void testProperties() throws SQLException {
   		ApplicationContext ctx = new ClassPathXmlApplicationContext(
   				"classpath*:beans-properties.xml");
   
   		DataSource dataSource= (DataSource) ctx.getBean("dataSource");
   		System.out.println(dataSource.getConnection());
   		
   	}
   

   测试结果：

   信息: Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, contextClassLoaderSource -> caller, dataSourceName -> 1hgeby99z1omdrfqfwsqk4|2d3ffb89, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.mysql.jdbc.Driver, extensions -> {}, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, forceSynchronousCheckins -> false, forceUseNamedDriverClass -> false, identityToken -> 1hgeby99z1omdrfqfwsqk4|2d3ffb89, idleConnectionTestPeriod -> 0, initialPoolSize -> 3, jdbcUrl -> jdbc:mysql://localhost:3306/test, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 15, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 3, numHelperThreads -> 3, preferredTestQuery -> null, privilegeSpawnedThreads -> false, properties -> {user=******, password=******}, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, userOverrides -> {}, usesTraditionalReflectiveProxies -> false ]
   com.mchange.v2.c3p0.impl.NewProxyConnection@7042876b [wrapping: com.mysql.jdbc.JDBC4Connection@1fc8bb61]