spring-boot读取props和yml配置文件

最近微框架spring-boot很火，笔者也跟风学习了一下，废话不多说，现给出一个读取配置文件的例子。
首先，需要在pom文件中依赖以下jar包

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>		
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

其次，我们需要一个spring-boot启动类

@SpringBootApplication
@EnableConfigurationProperties({PropsConfig.class,YmlConfig.class}) 
public class ReadApplication {
    public static void main(String[] args) {
        SpringApplication.run(ReadApplication.class, args);
    }
}

没错，@EnableConfigurationProperties注解里指出的PropsConfig.class,YmlConfig.class分别就是读取props和yml配置文件的类。接下来，我们分别进行读取properties和yml配置文件的具体实现。

1.读取properties配置文件
在类路径下放置一个application.properties文件，大致内容如下：

master.ds.driverClassName=com.mysql.jdbc.Driver
master.ds.url=jdbc:mysql://localhost:3306/test
master.ds.username=root
master.ds.password=root
master.ds.filters=stat
master.ds.maxActive=20
master.ds.initialSize=1
master.ds.maxWait=60000
master.ds.minIdle=10
master.ds.timeBetweenEvictionRunsMillis=60000
master.ds.minEvictableIdleTimeMillis=300000
master.ds.validationQuery=SELECT 'x'
master.ds.testWhileIdle=true
master.ds.testOnBorrow=false
master.ds.testOnReturn=false
master.ds.poolPreparedStatements=true
master.ds.maxOpenPreparedStatements=100
master.ds.removeAbandoned=true
master.ds.removeAbandonedTimeout=1800
master.ds.logAbandoned=true

读取props配置的类，很简单，基本就是一个pojo/vo类，在类上加载@ConfigurationProperties注解即可。

@ConfigurationProperties(prefix = "master.ds",locations = "classpath:application.properties")
public class PropsConfig {
	private String driverClassName;
	private String url;
	private String username;
	private String password;
	private String filters;
	private String maxActive;
	private String initialSize;
	private String maxWait;
		
	public String getDriverClassName() {
		return driverClassName;
	}
	public void setDriverClassName(String driverClassName) {
		this.driverClassName = driverClassName;
	}
	public String getUrl() {
		return url;
	}
	public void setUrl(String url) {
		this.url = url;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	public String getFilters() {
		return filters;
	}
	public void setFilters(String filters) {
		this.filters = filters;
	}
	public String getMaxActive() {
		return maxActive;
	}
	public void setMaxActive(String maxActive) {
		this.maxActive = maxActive;
	}
	public String getInitialSize() {
		return initialSize;
	}
	public void setInitialSize(String initialSize) {
		this.initialSize = initialSize;
	}
	public String getMaxWait() {
		return maxWait;
	}
	public void setMaxWait(String maxWait) {
		this.maxWait = maxWait;
	}
}

单元测试类

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = ReadApplication.class)
public class ReadApplicationPropsTests {
	@Autowired
	private PropsConfig propsConfig;
	
	@Test
	public void testDisplayPropsValue() {
		String driverClassName = propsConfig.getDriverClassName();
		String url = propsConfig.getUrl();
		String username = propsConfig.getUsername();
		String password = propsConfig.getPassword();
		
		String filters = propsConfig.getFilters();
		String maxActive = propsConfig.getMaxActive();
		String initialSize = propsConfig.getInitialSize();
		String maxWait = propsConfig.getMaxWait();
				
		System.out.println("driverClassName -> " + driverClassName);
		System.out.println("url -> " + url);
		System.out.println("username -> " + username);
		System.out.println("password -> " + password);
		
		System.out.println("initialSize -> " + initialSize);
		System.out.println("maxWait -> " + maxWait);
		
	}
}

可以看到在控制台输出的测试内容：

driverClassName -> com.mysql.jdbc.Driver
url -> jdbc:mysql://localhost:3306/test
username -> root
password -> root
initialSize -> 1
maxWait -> 60000

2.读取yml配置文件
在类路径下放置一个application.yml文件，大致内容如下：

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

读取yml配置文件的类。

@ConfigurationProperties(prefix="myProps") //application.yml中的myProps下的属性  
public class YmlConfig {
    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;  
    }  
      
    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;  
    } 
}

单元测试类

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = ReadApplication.class)
public class ReadApplicationYmlTests {
	@Autowired
	private YmlConfig ymlConfig;
	
	@Test
	public void testDisplayYmlValue() throws JsonProcessingException {
		System.out.println("simpleProp: " + ymlConfig.getSimpleProp());  
		
		ObjectMapper objectMapper = new ObjectMapper();
	    System.out.println("arrayProps: " + objectMapper.writeValueAsString(ymlConfig.getArrayProps()));  
	    System.out.println("listProp1: " + objectMapper.writeValueAsString(ymlConfig.getListProp1()));  
	    System.out.println("listProp2: " + objectMapper.writeValueAsString(ymlConfig.getListProp2()));  
	    System.out.println("mapProps: " + objectMapper.writeValueAsString(ymlConfig.getMapProps()));  

	}
}

可以看到在控制台输出的测试内容：

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"}

是不是很神奇，不需要spring的applicationContext.xml文件也可以顺利运行之。