springboot如何通过@Value,@ConfigurationProperties获取配置

目录

• 通过@Value,@ConfigurationProperties获取配置
• spring boot 获取配置项值
• 通过@Value 获取值
• 通过@ConfigurationProperties 获取值
• 说下@ConfigurationProperties和@Value区别
• 配置文件注入值数据校验

通过@Value,@ConfigurationProperties获取配置

spring boot 获取配置项值

使用版本是1.5.4

举例一个线程池的配置：

在application.yml添加配置项及值

    # 线程池配置
    taskexecutor:
      corePoolSize: 5
      maxPoolSize: 10
      queueCapacity: 25

通过@Value 获取值

@Configuration
@EnableAsync
public class ExecutorConfig {
    @Value("${taskexecutor.corePoolSize}")
    private int corePoolSize;
    @Value("${taskexecutor.maxPoolSize}")
    private int maxPoolSize;
    @Value("${taskexecutor.queueCapacity}")
    private int queueCapacity;
    @Bean
    public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(corePoolSize);
        executor.setMaxPoolSize(maxPoolSize);
        executor.setQueueCapacity(queueCapacity);
        executor.setThreadNamePrefix("TaskExecutor-");
        executor.initialize();
        return executor;
    }
    }

通过@ConfigurationProperties 获取值

    @Configuration
    @EnableAsync
    @ConfigurationProperties(ignoreUnknownFields = false，prefix = "taskexecutor")
    public class ExecutorConfig {
    private int corePoolSize;
    private int maxPoolSize;
    private int queueCapacity;
    @Bean
    public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(corePoolSize);
        executor.setMaxPoolSize(maxPoolSize);
        executor.setQueueCapacity(queueCapacity);
        executor.setThreadNamePrefix("TaskExecutor-");
        executor.initialize();
        return executor;
    }
    }

通过@ConfigurationProperties加载配置文件，将配置项与bean及属性关联，指定ignoreUnknownFields当有属性未匹配到值时会抛出异常，用prefix指定配置项的前缀。

@ConfigurationProperties还支持层级结构、 布尔、集合等类型的值注入

http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-features-external-config-typesafe-configuration-properties

说下@ConfigurationProperties和@Value区别

配置文件yml还是properties他们都能获取到值;

如果说, 只是在某个业务逻辑中需要获取一项配置文件中的某项值, 使用@Value

如果说，专门编写了一个javaBean 来和配置文件进行映射，我们就直接使用@ConfigurationProperties;

配置文件注入值数据校验

@Component
@ConfigurationProperties(prefix = "person")
@Validated
public class Person {

    /**
     * <bean class="Person">
     *      <property name="lastName" value="字面值/${key} 从环境变量，配置文件中获取值/#{Spel}"></property>
     * </bean>
     */
    //Value("${person.last-name}")
    //lastName必须为邮箱格式
    @Email
    private String lastName;
    //@Value("#{11*2}")
    private Integer age;
    //@Value("true")
    private Boolean boss;
    private Date birth;
    private Map<String, Object> maps;
    private List<Object> list;
    private Dog dog;

以上为个人经验，希望能给大家一个参考，也希望大家多多支持我们。