about 4 years ago
在Spring中有提供設定檔的工具方便載入，並可以在xml跟java中可以自動注入變數，相當方便
使用PropertyPlaceholderConfigurer或是util:properties
方案一 使用PropertyPlaceholderConfigurer
要使用context元素記得要先加上context定義
xmlns:context="http://www.springframework.org/schema/context"
還有提供xsd對應檔位置
xsi:schemaLocation="
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.2.xsd"
不然Spring不認識context:property-placeholder喔
下面是常用的定義檔
<?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:context="http://www.springframework.org/schema/context"
xmlns:util="http://www.springframework.org/schema/util"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.2.xsd
http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util-3.2.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">
在spring設定檔中這樣引用
<bean id="placeholderConfig"
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="fileEncoding" value="UTF-8" />
<property name="location" value="classpath:config.properties" />
<property name="ignoreUnresolvablePlaceholders" value="true" />
</bean>
讀取外部檔案
<bean id="placeholderConfig" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="fileEncoding" value="UTF-8" />
<property name="location" value="file:///D:/testtomcat/data0/etc/wechat/jdbc.properties" />
<property name="ignoreUnresolvablePlaceholders" value="true" />
</bean>
Spring3.0後可以這樣寫
<context:property-placeholder location="classpath:config.properties" file-encoding="UTF-8" ignore-unresolvable="true" />
Loading multiple properties files
<bean id="appProperties"
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<list>
<value>classpath:mail.properties</value>
<value>classpath:database.properties</value>
</list>
</property>
</bean>
如果有多個設定檔則ignore-unresolvable要設成true
就可以在其他設定檔中使用這個參數如下
<bean name="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="url" value="${jdbc_url}" />
<property name="username" value="${jdbc_username}" />
<property name="password" value="${jdbc_password}" />
</bean>
或如果想在java中取得此變數可以這樣
@Value("${jdbc_url}")
private String jdbcUrl;
就可以取到一樣的值
但是這變數是有可能重複到互相覆蓋，也不太好辨識在哪個設定檔，你也可以使用方案二
方案二 使用util:properties
在Spring設定檔中增加命名xmlns:util跟spring-util-3.2.xsd，並加上util:properties
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:util="http://www.springframework.org/schema/util"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.2.xsd
http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util-3.2.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">
<util:properties id="securitysource" location="classpath:security.properties" />
</beans>
設定檔
sessiontimeout=30
你便可以在java中使用這樣方法獲得變數
@Value("#{securitysource[sessiontimeout]}")
private Long sessiontimeout;
