SpringBoot获取application的参数值

1. 获取.properties/.yml方法

注意事项： 在 .yml 配置时，冒号（:）后面一定要有空格， 没有空格可能会有一下情况

• 使用Environment和封装类时，值为null
• 使用@Value时，spring boot项目启动时会报：org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘webController’: Injection of autowired dependencies failed; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder ‘test.testMsg’ in value “${test.testMsg}”

1. 方法一：使用@Value(“”)

2. 方法二：使用Environment

package com.rit.demo.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.env.Environment;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping("/webCon")
public class WebController {
    @Value("${test.testMsg}")
    private String msg;
    @Autowired
    private Environment env;
    @RequestMapping("/index1")
    public String index1() {
        return "方式一："+msg;
    }
    @RequestMapping("/index2")
    public String index2() {
        return "方式二："+env.getProperty("redis.province.redisKey");
    }
}

#application.properties
redis.province.redisKey=witkeyProvince

正确配置：
错误配置：

3. 方法三：使用封装类

1. 创建application.yml
2. 引入依赖
3. 创建bean
4. 创建测试类

   #application.yml
   myProps: #自定义的属性和值  
   simpleProp: simplePropValue  
   arrayProps: 1,2,3,4,5  
   listProp1:  
    - name: abc  
      value: abcValue  
    - name: efg  
      value: efgValue  
   listProp2:  
    - config2Value1  
    - config2Vavlue2  
   mapProps:  
    key1: value1  
    key2: value2

   ```xml

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-configuration-processor</artifactId>
        <optional>true</optional>
    </dependency>

```java
//bean.class
package com.rit.demo.pojo;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
@Component
//接收application.yml中的wechat下面的屬性
@ConfigurationProperties(prefix = "my-props")
public class ReadApplicationUntil {
     private String simpleProp;  
        private String[] arrayProps;  
        private List<Map<String, String>> listProp1 = new ArrayList<>(); //接收prop1里面的属性值  
        private List<String> listProp2 = new ArrayList<>(); //接收prop2里面的属性值  
        private Map<String, String> mapProps = new HashMap<>(); //接收prop1里面的属性值  
        public String getSimpleProp() {  
            return simpleProp;  
        }  
        //String类型的一定需要setter来接收属性值；maps, collections, 和 arrays 不需要  
        public void setSimpleProp(String simpleProp) {  
            this.simpleProp = simpleProp;  
        }  
        public List<Map<String, String>> getListProp1() {  
            return listProp1;  
        }  
        public List<String> getListProp2() {  
            return listProp2;  
        }  
        public String[] getArrayProps() {  
            return arrayProps;  
        }  
        public void setArrayProps(String[] arrayProps) {  
            this.arrayProps = arrayProps;  
        }  
        public Map<String, String> getMapProps() {  
            return mapProps;  
        }  
        public void setMapProps(Map<String, String> mapProps) {  
            this.mapProps = mapProps;  
        }  
}

//测试类
package com.rit.demo.test;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.rit.demo.pojo.ReadApplicationUntil;
@SpringBootTest
public class YmlTest {
    private final ObjectMapper objectMapper = new ObjectMapper();
    @Autowired
    private ReadApplicationUntil applicationUntil;
    @Test
    public void yml() throws JsonProcessingException {
        System.out.println("simpleProp: " + applicationUntil.getSimpleProp());  
        System.out.println("arrayProps: " + objectMapper.writeValueAsString(applicationUntil.getArrayProps()));  
        System.out.println("listProp1: " + objectMapper.writeValueAsString(applicationUntil.getListProp1()));  
        System.out.println("listProp2: " + objectMapper.writeValueAsString(applicationUntil.getListProp2()));  
        System.out.println("mapProps: " + objectMapper.writeValueAsString(applicationUntil.getMapProps())); 
    }
}

测试结果： simpleProp: simplePropValue arrayProps: [“1”,”2”,”3”,”4”,”5”] listProp1: [{“name”:”abc”,”value”:”abcValue”},{“name”:”efg”,”value”:”efgValue”}] listProp2: [“config2Value1”,”config2Vavlue2”]

mapProps: {“key1”:”value1”,”key2”:”value2”}

补充知识：

如何执行测试类：