SpringBoot注解@ConfigurationProperties配置提示

一、使用

1. 配置Bean

@Component
@ConfigurationProperties(prefix = "pay")
@Data
public class PayConfig {
	/**
	 * 签名
	 */
	private String signCode = "11111";

	/**
	 * 超时时间，单位：秒
	 */
	private Integer timeOutOfSeconds;

	/**
	 * 请求URL
	 */
	private Url url;

	@Data
	public static class Url {
		/**
		 * url - 微信
		 */
		private String weixin;
		/**
		 * url - 支付宝
		 */
		private String zhifubao;
	}
}

1. @Component 让 Bean 被扫描
2. @Data 添加 getter、setter 方法，没有不行

2. 添加依赖

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

3. run 或 debug 或 maven compile

完成！

第3步后，会生成一个文件：/target/classes/META-INF/spring-configuration-metadata.json

配置提示效果图

二、@ConfigurationProperties 相关参数

@Target({ ElementType.TYPE, ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ConfigurationProperties {

	@AliasFor("prefix")
	String value() default "";

	@AliasFor("value")
	String prefix() default "";

	boolean ignoreInvalidFields() default false;

	boolean ignoreUnknownFields() default true;

}

1. ignoreInvalidFields

1. 默认 false，表示不忽略无效的字段
2. 无效字段，一般是指配置了错误的类型

   1. 类型是 Boolean，配置却不是 true/false
   2. 类型是 Integer，配置却不是数字

3. 当为 false 时，且配置了无效字段，启动时会报错

java.lang.IllegalStateException: Failed to load ApplicationContext
Caused by: org.springframework.boot.context.properties.ConfigurationPropertiesBindException: Error creating bean with name 'payConfig': Could not bind properties to 'PayConfig' : prefix=pay, ignoreInvalidFields=false, ignoreUnknownFields=true; nested exception is org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under 'pay.time-out-of-seconds' to java.lang.Integer
Caused by: org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under 'pay.time-out-of-seconds' to java.lang.Integer
Caused by: org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.String] to type [java.lang.Integer] for value 'asdf'; nested exception is java.lang.NumberFormatException: For input string: "asdf"
Caused by: java.lang.NumberFormatException: For input string: "asdf"

4. 当为 false 时，且配置了无效字段，启动成功，但不会绑定，字段值为 null

@SpringBootTest
public class ConfigTipTest {

	@Autowired
	private PayConfig payConfig;

	@Test
	public void test01() {
		System.out.println(payConfig.getTimeOutOfSeconds());
	}
}

// 打印结果
null

2. ignoreUnknownFields

忽略未知字段，默认 true

未知字段，就是配置的 key，与 Bean 对应不起来

当 ignoreUnknownFields = false，且配置了未知字段时，启动会报错

java.lang.IllegalStateException: Failed to load ApplicationContext
Caused by: org.springframework.boot.context.properties.ConfigurationPropertiesBindException: Error creating bean with name 'payConfig': Could not bind properties to 'PayConfig' : prefix=pay, ignoreInvalidFields=false, ignoreUnknownFields=false; nested exception is org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under 'pay' to com.balsam.study.spring.boot.config.tip.PayConfig
Caused by: org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under 'pay' to com.balsam.study.spring.boot.config.tip.PayConfig
Caused by: org.springframework.boot.context.properties.bind.UnboundConfigurationPropertiesException: The elements [pay.time-out-of-secondsHAHA] were left unbound.

备注：由于配置中的 Key-Value 可能在其它地方被使用，所以 ignoreUnknownFields 参数不建议设置成 false

---

相关依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
</dependency>
// 包含 spring-boot-autoconfigure
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-autoconfigure</artifactId>
    <version>2.2.1.RELEASE</version>
    <scope>compile</scope>
</dependency>
// 包含 spring-boot-autoconfigure-processor、spring-boot-configuration-processor
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-autoconfigure-processor</artifactId>
    <version>2.2.1.RELEASE</version>
    <scope>compile</scope>
    <optional>true</optional>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-configuration-processor</artifactId>
    <version>2.2.1.RELEASE</version>
    <scope>compile</scope>
    <optional>true</optional>
</dependency>
// 需要的是 spring-boot-configuration-processor