Spring中加载propertities配置文件

￡神魔★判官ぃ 2022-07-13 06:56 59阅读 0赞

0、Spring加载classpath路径下的propertities配置文件

<bean
    		class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    		
    		<property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
    		
    		<property name="ignoreResourceNotFound" value="true" />
    		
    		<property name="locations">
    			<list>
    				<value>classpath:baseInfo.properties</value>
    				<value>classpath:db.properties</value>
    			</list>
    		</property>
    	</bean>

db.properties的配置

jdbc.driver=com.mysql.jdbc.Driver
    jdbc.url=jdbc:mysql://localhost:3306/student
    jdbc.username=root
    jdbc.password=1234

baseInfo.properties的配置

my.jspPath=/jsp
    my.htmlPath=/html

1、用于数据库连接池的配置

2、在Java程序中使用propertities中的配置

import org.springframework.beans.factory.annotation.Value;
    import org.springframework.stereotype.Service;
    
    @Service
    public class ProService {
    	@Value("${my.jspPath}")
    	private String jspPath;
    	@Value("${my.htmlPath}")
    	private String htmlPath;
    
    	public void test() {
    		System.out.println("jspPath:" + this.jspPath + ", htmlPath:"
    				+ this.htmlPath);
    	}
    }

注意baseInfo.properties和ProService.java的代码实现

![20161229173025458][]

3、自定义实现propertities配置文件的加载

使用上面的方法，**但是这有一个问题，我每用一次配置文件中的值，就要声明一个局部变量。有没有用代码的方式，直接读取配置文件中的值。****答案就是重写PropertyPlaceholderConfigurer。**

3.1 重写PropertyPlaceholderConfigurer

import java.util.HashMap;
    import java.util.Map;
    import java.util.Properties;
    import org.springframework.beans.BeansException;
    import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
    import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
    
    public class PropertyPlaceholder extends PropertyPlaceholderConfigurer {
    
    	private static Map<String, String> propertyMap;
    
    	@Override
    	protected void processProperties(
    			ConfigurableListableBeanFactory beanFactoryToProcess,
    			Properties props) throws BeansException {
    		super.processProperties(beanFactoryToProcess, props);
    		propertyMap = new HashMap<String, String>();
    		for (Object key : props.keySet()) {
    			String keyStr = key.toString();
    			String value = props.getProperty(keyStr);
    			propertyMap.put(keyStr, value);
    		}
    	}
    
    	// static method for accessing context properties
    	public static Object getProperty(String name) {
    		return propertyMap.get(name);
    	}
    }

3.2 在Spring的配置文件里面， 用上面的类，代替PropertyPlaceholderConfigurer

<bean class="com.utils.PropertyPlaceholder">
    		
    		<property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
    		
    		<property name="ignoreResourceNotFound" value="true" />
    		
    		<property name="locations">
    			<list>
    				<value>classpath:baseInfo.properties</value>
    				<value>classpath:db.properties</value>
    			</list>
    		</property>
    	</bean>

3.2 Java程序中的用法

import org.springframework.stereotype.Service;
    
    import com.utils.PropertyPlaceholder;
    
    @Service
    public class MyProService {
    
    	public void test() {
    		System.out.println("jspPath:"
    				+ PropertyPlaceholder.getProperty("my.jspPath") + ", htmlPath:"
    				+ PropertyPlaceholder.getProperty("my.htmlPath"));
    	}
    }

**        具体的代码实现，就是PropertyPlaceholder.getProperty("my.jspPath").**

4、测试代码

public class App {
    	public static void main(String[] args) {
    		ApplicationContext context = new ClassPathXmlApplicationContext(
    				"classpath:spring/bean-*.xml");
    		System.out.println(context);
    
    		// 获取并测试
    		ProService proService = context.getBean("proService", ProService.class);
    		System.out.println(proService);
    		proService.test();
    
    		// 获取并测试
    		MyProService myproService = context.getBean("myProService",
    				MyProService.class);
    		System.out.println(myproService);
    		myproService.test();
    		// 获取并测试
    		DataSource dataSource = context.getBean("dataSource", DataSource.class);
    		System.out.println(dataSource);
    	}
    }

5、[源码下载][Link 1]

[20161229173025458]: /images/20220713/b7133c3b1ddb42ca853df38923dd0fe4.png
[Link 1]: http://pan.baidu.com/s/1pLvuc59