java web項目讀取配置文件properties的3種方式

首先我的配置文件名稱：cdsssms.properties，內容如下：

ORDER_URL=http://xx.xx.x.x:8888/sms.aspx
USER_ID=311147
ACCOUNT_NO=kp11l
ACCOUNT_PASSWORD=10003451

1、第一種使用文件流方式讀取。

讀取多個properties文件的例子。此例子直接可以用於到項目中。

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 
 *  @Description:Properties配置文件工具
 *  
 */
public class ConfigUtil {
	
	private static Logger logger = LoggerFactory.getLogger(ConfigUtil.class);//日誌		
	final static Properties props = new Properties();//配置文件對象
	static String rootPath=  "";
	/**加密項目的文件路徑**/
	public static final String IMAGEURl = ConfigUtil.getGetProperties("parameter").getProperty("imagePath").toString();
	public static final String PAGE_DIR = ConfigUtil.getGetProperties("parameter").getProperty("pageDir").toString();
	public static final String CLASS_DIR = ConfigUtil.getGetProperties("parameter").getProperty("classDir").toString();
	public static final String PROJECT_NAME = ConfigUtil.getGetProperties("parameter").getProperty("projectName").toString();
	public static final String PROJECT_URL = ConfigUtil.getGetProperties("parameter").getProperty("projectUrl").toString();
	/**短信通道的參數**/
	public static final String ORDER_URL = ConfigUtil.getGetProperties("cdsssms").getProperty("ORDER_URL").toString();
	public static final String USER_ID = ConfigUtil.getGetProperties("cdsssms").getProperty("USER_ID").toString();
	public static final String ACCOUNT_NO = ConfigUtil.getGetProperties("cdsssms").getProperty("ACCOUNT_NO").toString();
	public static final String ACCOUNT_PASSWORD =  ConfigUtil.getGetProperties("cdsssms").getProperty("ACCOUNT_PASSWORD").toString();
		
	
	/**
	 * 
	 * @Description:得到Properties配置文件
	 * @param propertiesName(配置文件路徑)
	 * @param programName  項目名
	 * @throws
	 */
	public static  Properties getGetProperties(String propertiesName, String programName){
		String url = getUrl(programName);
		setPro(url, propertiesName);
		return props;
	}
	/**
	 * 
	* @Title: getGetPropertiesByClass 
	* @Description: 通過class類得到當前配置文件路徑
	* @param cls
	* @param propertiesName
	* @return Properties   
	* @author ganjing
	* @throws
	 */
	public static  Properties getGetPropertiesByClass(Class<?> cls, String propertiesName){
		String url = getClassUrl(cls);
		setPro(url, propertiesName);
		return props;
	}
	
	/**
	 * 
	 * @Description:得到Properties配置文件
	 * @param propertiesName 配置文件中的屬性名稱
	 * @return Properties  
	 * @throws
	 */
	public static  Properties getGetPropertiesForJar(String propertiesName){
		String url = getUrlForJar();
		setPro(url, propertiesName);
		return props;
	}
	
	/**
	 * 
	 * @Description: 獲得classpath基礎路徑
	 * 
	 * @return
	 */
	private static String getUrl(String programName) {
		rootPath = ConfigUtil.class.getResource("").toString();
		String url = null;
		if (System.getProperty("os.name").toLowerCase().indexOf("window") > -1) {
			url = rootPath.replace("file:/", "").replace("%20", " ")
					.split("/com")[0];
		} else {
			url = rootPath.replace("file:", "").replace("%20", " ")
					.split("/com")[0];
		}
		String separator = "/";
		String url1 = url.substring(0, url.lastIndexOf(separator));
		String url2 = url.substring(url1.lastIndexOf(separator), url1.length());
		url1 = url1.substring(0, url1.lastIndexOf(separator));
		url1 = url1.substring(0, url1.lastIndexOf(separator));
		String url3 = url.substring(url.lastIndexOf(separator), url.length());
		return url1 + File.separator + programName+ url2+url3;
	}
	private static String getClassUrl(Class<?> cls) {
		return cls.getClassLoader().getResource("").getPath();
	}
	
	/**
	 * 
	 * @author jl
	 * @Description: 返回jar運行同級目錄config
	 * @date:2017年3月13日 下午4:21:00
	 * @return
	 */
	private static String getUrlForJar() {
		return "config";
	}
	
	/**
	 * 
	 * @Description: 獲得properties文件
	 * @date:2017年3月13日 下午4:26:36
	 */
	private static void setPro(String url, String propertiesName) {
		FileInputStream fileIo = null;
		BufferedInputStream bufferIo = null;
		try {
			fileIo = new FileInputStream(url+File.separator+propertiesName+".properties");
			bufferIo = new BufferedInputStream(fileIo);
			props.load(bufferIo);
		} catch (Exception e) {
			logger.error("讀取項目的配置文件加載異常：{}",e);
		} finally {
			try {
				fileIo.close();
				bufferIo.close();
			} catch (IOException e) {
				logger.error("讀取項目的配置文件加載異常：{}",e);
				try {
					bufferIo.close();
				} catch (IOException e1) {
					logger.error("讀取項目的配置文件加載異常：{}",e1);
				}
			}
			
		}
	}
		
	/**
	 * 
	 * @Description:得到Properties配置文件
	 * @param  propertiesName 配置文件的名稱   
	 * @return Properties     配置文件中的數據
	 * @throws
	 */
	public static  Properties getGetProperties(String propertiesName){
		rootPath = ConfigUtil.class.getResource("").toString();
		String url = null;
		if (System.getProperty("os.name").toLowerCase().indexOf("window") > -1) {
			url = rootPath.replace("file:/", "").replace("%20", " ")
					.split("/com")[0];
		} else {
			url = rootPath.replace("file:", "").replace("%20", " ")
					.split("/com")[0];
		}
		FileInputStream fileIo = null;
		BufferedInputStream bufferIo = null;
		try {
			fileIo = new FileInputStream(url+File.separator+propertiesName+".properties");
			bufferIo = new BufferedInputStream(fileIo);
			props.load(bufferIo);
		} catch (Exception e) {
			logger.error("讀取項目的配置文件加載異常：{}",e);
		} finally {
			try {
				fileIo.close();
				bufferIo.close();
			} catch (IOException e) {
				logger.error("讀取項目的配置文件加載異常：{}",e);
				try {
					bufferIo.close();
				} catch (IOException e1) {
					logger.error("讀取項目的配置文件加載異常：{}",e1);
				}
			}
			
		}
		return props;
	}
	
}

要看更詳細的原理介紹請參考鏈接地址：https://www.cnblogs.com/super-yu/p/8622463.html

2、第二種使用PropertyPlaceHolderConfigurer

spring項目的配置文件具體配置如下：

<?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"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans-4.0.xsd  
                        http://www.springframework.org/schema/context
                        http://www.springframework.org/schema/context/spring-context-4.0.xsd">
                        
    <!-- 使用註解注入properties中的值 -->
	<bean id="SDKConfig" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
		<!-- ignoreUnresolvablePlaceholders爲是否忽略不可解析的 Placeholder，如配置了多個PropertyPlaceholderConfigurer，則需設置爲true -->
		<property name="ignoreUnresolvablePlaceholders" value="true" />  
		<property name="locations">
			<list>
				<value>classpath:/config/${package.env}/mobile.properties</value>
				<value>classpath:/config/${package.env}/db.properties</value>
				<value>classpath:/config/${package.env}/cdsssms.properties</value>
			</list>
		</property>
		<!-- 設置編碼格式 -->
        <property name="fileEncoding" value="UTF-8"></property>
	</bean>
</beans>

開始我把@Value("${msg.send.url}")用在controller的一個類中使用。報錯：

Error creating bean with name   'creditCardPaymentController': Injection of autowired dependencies failed; nested exception is  org.springframework.beans.factory.BeanCreationException: Could not
autowire field: private java.lang.String com.qingyu.pay.mobile.controller.CreditCardPaymentController.smsOrderUrl;

根據報錯：在我的creditCardPaymentController中短信配置文件注入失敗，證明spring加載配置文件都沒有加載成功。然後查檢項目的配置文件：

<context:component-scan base-package="com.xxxxx.xxx">

<context:include-filter  type="annotation"  expression="org.springframework.stereotype.Service"/>  

</context:component-scan>

發現我沒有把controller包放入component-scan中掃描。所以報此錯。一般配置文件的使用引入到Service層中使用。所以我創建了一個Service類，代碼如下：

@Service("sendMsgService")
public class SendMsgService {
    private static final Logger logger = LoggerFactory.getLogger(SendMsgService.class);
    
    @Value("${ORDER_URL}")
    private String             smsOrderUrl;
    
    @Value("${USER_ID}")
    private String             smsUserID;
    
    @Value("${ACCOUNT_NO}")
    private String              smsAccountNo;
    
    @Value("${ACCOUNT_PASSWORD}")
    private String              smsPassword;

    public String sendSmsRequest(){
    	logger.info("短信發送的userId:{},accountNo:{},password:{},url:{}",smsUserID,smsAccountNo,smsPassword,smsOrderUrl);
    	return "";
    }
｝

要深入瞭解PropertyPlaceHolderConfigurer的實現原理請參考以下blog：

https://www.cnblogs.com/fnlingnzb-learner/p/10384742.html

https://blog.csdn.net/u013789656/article/details/80937687

https://blog.csdn.net/CSDN19951017/article/details/84031375

3、第三種使用PropertiesFactoryBean

使用格式：@Value("#{SDKConfig['xf.payDF.url']}")

spring項目配置文件：

<?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"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
         http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd">
	<!-- 使用註解注入properties中的值 -->
	<bean id="SDKConfig" class="org.springframework.beans.factory.config.PropertiesFactoryBean">  
	    <property name="locations">
	        <array>
	            <value>classpath:xf-sdk.properties</value>
	            <value>classpath:xfx-sdk.properties</value>
	            <value>classpath:dd-sdk.properties</value>
	            <value>classpath:prop.properties</value>
	        </array>  
	    </property>
	    <!-- 設置編碼格式 -->
		<property name="fileEncoding" value="UTF-8"></property>
	</bean>  

</beans>

Service類的代碼：

@Service("sendMsgService")
public class SendMsgService {
    private static final Logger logger = LoggerFactory.getLogger(SendMsgService.class);
    
    @Value("#{SDKConfig['ORDER_URL']}")
    private String             smsOrderUrl;
    
    @Value("#{SDKConfig['USER_ID']}")
    private String             smsUserID;
    
    @Value("#{SDKConfig['ACCOUNT_NO']}")
    private String              smsAccountNo;
    
    @Value("#{SDKConfig['ACCOUNT_PASSWORD']}")
    private String              smsPassword;

    public String sendSmsRequest(){
    	logger.info("短信發送的userId:{},accountNo:{},password:{},url:{}",smsUserID,smsAccountNo,smsPassword,smsOrderUrl);
    	return "";
    }
｝

參考鏈接代碼：https://blog.csdn.net/qq_1017097573/article/details/62897645

總結：PropertyPlaceholderConfigurer 與PropertiesFactoryBean 區別：

使用 PropertyPlaceholderConfigurer 時， @Value表達式的用法是 @Value(value="${properties key}") ，

使用 PropertiesFactoryBean 時，我們還可以用@Value 讀取 properties對象的值， @Value 用法 是 @Value(value="#{configProperties['properties key']}")