Loading of .properties files, and application of el expressions

//When configuring the database, pay attention
to the automatic configuration of the dbcp data source transaction, otherwise it cannot be submitted

        <property name="defaultAutoCommit">

        <value>false</value>

       </property>



Usage 1:

<?xml version=" 1.0" encoding="UTF-8"?>

<beans

         xmlns="http://www.springframework.org/schema/beans"

         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance "

         xmlns:p="http://www.springframework.org/schema/p"

         xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/ beans/spring-beans-2.5.xsd">



<!-- Use the PropertyPlaceholderConfigurer provided by spring to read database configuration information.properties -->

         <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

                   <property name="locations">

                            <list>

                                     <!—

1. The classpath here can be considered as the src in the project-
2. The property name is locations, and the sub-tag <list></list> can be used to specify the configuration files of multiple databases. One is specified here
->

                                     <value>classpath:resource/config/jdbc.properties</value>

                            </ list>

                   </property>

         </bean>

The database configuration file project path at this time is like this.



Usage 2: To

read the database configuration file, you can also use the following method

<?xml version="1. 0" encoding="UTF-8"?>



<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-2.0.xsd">

  <bean id="propertyConfigurer" class="org.springframework.beans.factory.config .PropertyPlaceholderConfigurer">

    <property name="locations">

      <list>

         <value>/WEB-INF/config_test/jdbc.properties</value>

      </list>

    </property>

  </bean>

jdbc.properties file at this time The location is shown in the figure below.



There can be multiple properties configuration files. Here, two data configuration files are specified in the <list></list> tags

< ?xml version="1.0" encoding="UTF-8"?>

<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-2.0.xsd">

  <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

    <property name="locations">

      <list>

        <value>classpath:jdbc.properties</value>

        <value>/WEB-INF/config_test/jdbc.properties</value>

      </list>

    </property>

  </bean>

classpath:jdbc.The file location corresponding to properties is: sqlserver.password=sqlserver sqlserver.username=sa



The content of the file is: The connection information of sqlserver is configured





sqlserver.url=jdbc\:jtds\:sqlserver\://localhost\:1433/J2EE

sqlserver.driver=net.sourceforge.jtds.jdbc.Driver

/WEB-INF/config_test/jdbc.properties The corresponding file location is



file The content is: The connection information of oracle is configured

jdbc.driverClassName=oracle.jdbc.driver.OracleDriver

jdbc.url=jdbc:oracle:thin:@127.0.0.1:1521:orcl

jdbc.username=jxbms

jdbc.password=

jxbms After the configuration information of the database is read, it can be used when creating a datasource. Connect to oracle

below and use apache's dbcp data source

<bean id="dataSource"

       class="org.apache.commons.dbcp.BasicDataSource"

       destroy-method ="close">

       <property name="driverClassName">

           <value>${jdbc.driverClassName}</value>

       < /property>

       <property name="url">

           <value>${jdbc.url}</value>

       </property>

       <property name="username">

           <value>${jdbc.username}</value>

       </property>

       <property name="password">

           <value>${jdbc.password}</value>

       </property>

       <property name="maxActive">

           <value>100</value>

       </property>

       <property name="maxIdle">

           <value>3</value>

       </property>

       <property name="maxWait">

           <value>-1</value>

       </property>

       <property name="defaultAutoCommit">































Then I thought that I could finally breathe a sigh of relief now, who knew that the sky was not what people wanted. When a table is replaced for testing, the data in the database still does not change. Is the c3p0 data source not easy

to use? After being tortured by the code again, I

finally found that the test java file was changed, not in a project, and other projects were closed. That's good.

When the document was written here, I suddenly found that the dbcp data source used by oracle has this configuration

        <property name="defaultAutoCommit">

        <value>false</value>

       </property>

The automatic transaction of the original dbcp data source The commit function is turned off.

Immediately change the transaction auto-commit to true for testing, everything is ok, (^ _ ^)