spring初步學習---注入配置檔案變數
阿新 • • 發佈：2019-01-02
Spring是一個輕量級控制反轉(IoC)和麵向切面(AOP)的容器框架。
控制反轉——Spring通過一種稱作控制反轉（IoC）的技術促進了鬆耦合。當應用了IoC，一個物件依賴的其它物件會通過被動的方式傳遞進來，而不是這個物件自己建立或者查詢依賴物件。
一.用maven引入spring包，pom.xml如下
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.practice</groupId> <artifactId>annotation</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>annotation</name> <url>http://maven.apache.org</url> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <!-- spring版本號 --> <spring.version>4.0.2.RELEASE</spring.version> </properties> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency> <!-- spring核心包 --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-oxm</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-tx</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> </dependency> </dependencies> </project>
下面介紹如何利用spring注入變數。
我想要把多個配置檔案中的資料注入到config物件中。
有兩個配置檔案：
jmq.properties
mq.producer.topic=wlogin_monitor
mq.epoll=falseredis-key-1 = mon_login redis-node-1 = 192.168.144.119:6379|192.168.144.120:6379 redis-key-2 = mon_register redis-node-2 = 192.168.144.119:6379|192.168.144.120:6379
二.用XML方式注入變數
把上述資料注入到LocalConf物件例項中，該類必須要有get，set方法。
mq.producer.topic注入到topic變數中，redis相關資料注入到modules變數中。
spring的配置檔案如下：public class LocalConf { private String topic; private Map<String,String> modules; public Map<String, String> getModules() { return modules; } public void setModules(Map<String, String> modules) { this.modules = modules; } public String getTopic() { return topic; } public void setTopic(String topic) { this.topic = topic; } }
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:jmq="http://code.jd.com/schema/jmq"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://code.jd.com/schema/jmq
http://code.jd.com/schema/jmq/jmq-1.0.xsd">
<bean id="propertyConfigurer"
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<list>
<value>classpath:conf/jmq.properties</value>
<value>classpath:conf/module.properties</value>
</list>
</property>
</bean>
<bean id="localConf" class="com.jd.jmq.main.LocalConf">
<property name="topic" value="${mq.producer.topic}"/>
<property name="modules">
<map>
<entry key="${redis-key-1}" value="${redis-node-1}"/>
<entry key="${redis-key-2}" value="${redis-node-2}"/>
</map>
</property>
</bean>
</beans>ApplicationContext context = new ClassPathXmlApplicationContext (new String[]{"conf/spring-producer.xml"});
LocalConf localConf = (LocalConf)context.getBean("localConf");就是這麼簡單！spring可以注入Java的各種容器，list，map，set等等。
三. 用Spring註解的方式
1.spring配置檔案<?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"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">
<!-- 自動掃描 -->
<context:component-scan base-package="com.practice.annotation" />
<!-- 引入配置檔案 -->
<bean id="configProperties" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
<property name="locations">
<list>
<value>classpath*:*.properties</value>
</list>
</property>
</bean>
<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PreferencesPlaceholderConfigurer">
<property name="properties" ref="configProperties" />
</bean>
</beans>2.測試類
package com.practice.annotation;
import java.util.Map;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({"classpath:spring.xml"})
public class App
{
@Value("#{configProperties['mq.producer.topic']}")
private String topic;
@Value("#{configProperties['mq.epoll']}")
private Boolean epoll;
@Value("#{configProperties}")
private Map<String,String> properties;
@Test
public void test(){
System.out.println("topic="+topic);
System.out.println("epoll="+epoll);
System.out.println(properties);
}
}
列印結果：
topic=wlogin_monitor
epoll=false
{redis-key-2=mon_register, mq.epoll=false, redis-node-2=192.168.144.119:6379|192.168.144.120:6379, redis-key-1=mon_login , redis-node-1=192.168.144.119:6379|192.168.144.120:6379 , providerName=Eclipse.org, pluginName=Java Development Tools JUnit Runtime Support,
mq.producer.topic=wlogin_monitor}
這裡providerName和pluginName變數也列印了，是因為spring.xml中引入的配置檔案是classpath*，即在整個專案目錄下搜尋所有的properties檔案。