spring-boot读取props和yml配置文件的方法

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。

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