1、使用@Value注解读取

读取properties配置文件时，默认读取的是application.properties。

application.properties：

demo.name=Name

demo.age=18

Java代码：

import org.springframework.beans.factory.annotation.Value;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class GatewayController {

@Value("${demo.name}")

private String name;

@Value("${demo.age}")

private String age;

@RequestMapping(value = "/gateway")

public String gateway() {

return "get properties value by ''@Value'' :" +

//1、使用@Value注解读取

" name=" + name +

" , age=" + age;

}

}

运行结果:

这里，如果要把

@Value("${demo.name}")

private String name;

@Value("${demo.age}")

private String age;

部分放到一个单独的类A中进行读取，然后在类B中调用，则要把类A增加@Component注解，并在类B中使用@Autowired自动装配类A，代码如下。

类A：

import org.springframework.beans.factory.annotation.Value;

import org.springframework.stereotype.Component;

@Component

public class ConfigBeanValue {

@Value("${demo.name}")

public String name;

@Value("${demo.age}")

public String age;

}

类B:

import cn.wbnull.springbootdemo.config.ConfigBeanValue;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class GatewayController {

@Autowired

private ConfigBeanValue configBeanValue;

@RequestMapping(value = "/gateway")

public String gateway() {

return "get properties value by ''@Value'' :" +

//1、使用@Value注解读取

" name=" + configBeanValue.name +

" , age=" + configBeanValue.age;

}

}

运行结果:

注意：如果@Value${}所包含的键名在application.properties配置文件中不存在的话，会抛出异常：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'configBeanValue': Injection of autowired dependencies failed;

nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'demo.name' in value "${demo.name}"

2、使用Environment读取

application.properties：

demo.sex=男

demo.address=山东

代码

import cn.wbnull.springbootdemo.config.ConfigBeanValue;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.core.env.Environment;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class GatewayController {

@Autowired

private ConfigBeanValue configBeanValue;

@Autowired

private Environment environment;

@RequestMapping(value = "/gateway")

public String gateway() {

return "get properties value by ''@Value'' :" +

//1、使用@Value注解读取

" name=" + configBeanValue.name +

" , age=" + configBeanValue.age +

"

get properties value by ''Environment'' :" +

//2、使用Environment读取

" , sex=" + environment.getProperty("demo.sex") +

" , address=" + environment.getProperty("demo.address");

}

}

运行结果:

这里，我们在application.properties做如下配置：

server.tomcat.uri-encoding=UTF-8

spring.http.encoding.charset=UTF-8

spring.http.encoding.enabled=true

spring.http.encoding.force=true

spring.messages.encoding=UTF-8

重新运行结果如下:

3、使用@ConfigurationProperties注解读取

在实际项目中，当项目需要注入的变量值很多时，上述所述的两种方法工作量会变得比较大，这时候我们通常使用基于类型安全的配置方式，将properties属性和一个Bean关联在一起，即使用注解@ConfigurationProperties读取配置文件数据。

在src\main\resources下新建config.properties配置文件：

demo.phone=10086

demo.wife=self

创建ConfigBeanProp并注入config.properties中的值：

import org.springframework.boot.context.properties.ConfigurationProperties;

import org.springframework.context.annotation.PropertySource;

import org.springframework.stereotype.Component;

@Component

@ConfigurationProperties(prefix = "demo")

@PropertySource(value = "config.properties")

public class ConfigBeanProp {

private String phone;

private String wife;

public String getPhone() {

return phone;

}

public void setPhone(String phone) {

this.phone = phone;

}

public String getWife() {

return wife;

}

public void setWife(String wife) {

this.wife = wife;

}

}

@Component 表示将该类标识为Bean

@ConfigurationProperties(prefix = "demo")用于绑定属性，其中prefix表示所绑定的属性的前缀。

@PropertySource(value = "config.properties")表示配置文件路径。

使用时，先使用@Autowired自动装载ConfigBeanProp，然后再进行取值，示例如下：

import cn.wbnull.springbootdemo.config.ConfigBeanProp;

import cn.wbnull.springbootdemo.config.ConfigBeanValue;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.core.env.Environment;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class GatewayController {

@Autowired

private ConfigBeanValue configBeanValue;

@Autowired

private Environment environment;

@Autowired

private ConfigBeanProp configBeanProp;

@RequestMapping(value = "/gateway")

public String gateway() {

return "get properties value by ''@Value'' :" +

//1、使用@Value注解读取

" name=" + configBeanValue.name +

" , age=" + configBeanValue.age +

"

get properties value by ''Environment'' :" +

//2、使用Environment读取

" sex=" + environment.getProperty("demo.sex") +

" , address=" + environment.getProperty("demo.address") +

"

get properties value by ''@ConfigurationProperties'' :" +

//3、使用@ConfigurationProperties注解读取

" phone=" + configBeanProp.getPhone() +

" , wife=" + configBeanProp.getWife();

}

}

运行结果:

4.使用PropertiesLoaderUtils

app-config.properties

#### 通过注册监听器(`Listeners`) + `PropertiesLoaderUtils`的方式

com.zyd.type=Springboot - Listeners

com.zyd.title=使用Listeners + PropertiesLoaderUtils获取配置文件

com.zyd.name=zyd

com.zyd.address=Beijing

com.zyd.company=in

PropertiesListener.java 用来初始化加载配置文件

package com.zyd.property.listener;

import org.springframework.boot.context.event.ApplicationStartedEvent;

import org.springframework.context.ApplicationListener;

import com.zyd.property.config.PropertiesListenerConfig;

/**

* 配置文件监听器，用来加载自定义配置文件

*

* @authoryadong.zhang* @date 2017年6月1日 下午3:38:25

* @version V1.0

* @since JDK ： 1.7

*/

public class PropertiesListener implements ApplicationListener{

private String propertyFileName;

public PropertiesListener(String propertyFileName) {

this.propertyFileName = propertyFileName;

}

@Override

public void onApplicationEvent(ApplicationStartedEvent event) {

PropertiesListenerConfig.loadAllProperties(propertyFileName);

}

}

PropertiesListenerConfig.java 加载配置文件内容

package com.zyd.property.config;

import java.io.IOException;

import java.io.UnsupportedEncodingException;

import java.util.HashMap;

import java.util.Map;

import java.util.Properties;

import org.springframework.beans.BeansException;

import org.springframework.core.io.support.PropertiesLoaderUtils;

/**

* 第四种方式：PropertiesLoaderUtils

*

* @authoryadong.zhang* @date 2017年6月1日 下午3:32:37

* @version V1.0

* @since JDK ： 1.7

*/

public class PropertiesListenerConfig {

public static Map propertiesMap = new HashMap<>();

private static void processProperties(Properties props) throws BeansException {

propertiesMap = new HashMap();

for (Object key : props.keySet()) {

String keyStr = key.toString();

try {

// PropertiesLoaderUtils的默认编码是ISO-8859-1,在这里转码一下

propertiesMap.put(keyStr, new String(props.getProperty(keyStr).getBytes("ISO-8859-1"), "utf-8"));

} catch (UnsupportedEncodingException e) {

e.printStackTrace();

} catch (java.lang.Exception e) {

e.printStackTrace();

}

}

}

public static void loadAllProperties(String propertyFileName) {

try {

Properties properties = PropertiesLoaderUtils.loadAllProperties(propertyFileName);

processProperties(properties);

} catch (IOException e) {

e.printStackTrace();

}

}

public static String getProperty(String name) {

return propertiesMap.get(name).toString();

}

public static MapgetAllProperty() {

return propertiesMap;

}

}

Applaction.java 启动类

package com.zyd.property;

import java.io.UnsupportedEncodingException;

import java.util.HashMap;

import java.util.Map;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

import com.zyd.property.config.PropertiesListenerConfig;

import com.zyd.property.listener.PropertiesListener;

/**

* @authoryadong.zhang* @date 2017年6月1日 下午3:49:30

* @version V1.0

* @since JDK ： 1.7

*/

@SpringBootApplication

@RestController

public class Applaction {

/**

*

* 第四种方式：通过注册监听器(`Listeners`) + `PropertiesLoaderUtils`的方式

*

* @author zyd

* @throws UnsupportedEncodingException

* @since JDK 1.7

*/

@RequestMapping("/listener")

public Maplistener() {

Map map = new HashMap();

map.putAll(PropertiesListenerConfig.getAllProperty());

return map;

}

public static void main(String[] args) throws Exception {

SpringApplication application = new SpringApplication(Applaction.class);

// 第四种方式：注册监听器

application.addListeners(new PropertiesListener("app-config.properties"));

application.run(args);

}

}