springboot获取properties文件的配置内容(转载)

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 +
                "<p>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 +
                "<p>get properties value by ''Environment'' :" +
                //2、使用Environment读取
                " sex=" + environment.getProperty("demo.sex") +
                " , address=" + environment.getProperty("demo.address") +
                "<p>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
 *
 * @author <a href="mailto:yadong.zhang0415@gmail.com">yadong.zhang</a>
 * @date 2017年6月1日 下午3:38:25
 * @version V1.0
 * @since JDK ： 1.7
 */
public class PropertiesListener implements ApplicationListener<ApplicationStartedEvent> {

    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
 *
 * @author <a href="mailto:yadong.zhang0415@gmail.com">yadong.zhang</a>
 * @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<String, String> propertiesMap = new HashMap<>();

    private static void processProperties(Properties props) throws BeansException {
        propertiesMap = new HashMap<String, String>();
        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 Map<String, String> getAllProperty() {
        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;

/**
 * @author <a href="mailto:yadong.zhang0415@gmail.com">yadong.zhang</a>
 * @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 Map<String, Object> listener() {
        Map<String, Object> map = new HashMap<String, Object>();
        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);
    }
}