SpringBoot中@ConfigurationProperties实现配置自动绑定的方法 SpringBoot中@ConfigurationProperties实

代码
构造器绑定
结合@PropertySource

代码 pom.xml：

4.0.0org.springframework.bootspring-boot-starter-parent2.6.2jarcom.kavenspringboot0.0.1-SNAPSHOTspringbootspringboot1.8org.springframework.bootspring-boot-starter-weborg.projectlomboklombokorg.springframework.bootspring-boot-maven-plugin

配置类：

package com.kaven.springboot.config; import lombok.Setter; import lombok.ToString; import org.springframework.boot.context.properties.ConfigurationProperties; import java.util.List; import java.util.Map; import java.util.Set; @ConfigurationProperties(prefix = "user")@Setter@ToStringpublic class UserProperties {private String username; private String password; private Set hobbies; private Map scores; private List userToken; }

UserToken类：

package com.kaven.springboot.config; import lombok.Setter; import lombok.ToString; @Setter@ToStringpublic class UserToken {private String token; }

接口：

package com.kaven.springboot.controller; import com.kaven.springboot.config.UserProperties; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RestController; import javax.annotation.Resource; @RestControllerpublic class ConfigController {@Resourceprivate UserProperties userProperties; @GetMapping("/config")public String getConfig() {return userProperties.toString(); }}

application.properties：

user.username="kaven"user.password="itkaven"user.hobbies[0]="A"user.hobbies[1]="B"user.hobbies[2]="C"user.scores.mathematics=145user.scores.english=80user.user-token[0].token="A"user.user-token[1].token="B"user.user-token[2].token="C"

启动类：

package com.kaven.springboot; import com.kaven.springboot.config.UserProperties; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.context.properties.EnableConfigurationProperties; @SpringBootApplication@EnableConfigurationProperties(value = https://www.it610.com/article/{UserProperties.class})//@ConfigurationPropertiesScan(basePackageClasses = {UserProperties.class})public class SpringbootApplication {public static void main(String[] args) {SpringApplication application = new SpringApplication(SpringbootApplication.class); application.run(args); }}

下面这两个注解都可以使得Spring Boot基于被@ConfigurationProperties注解修饰的类创建bean，因此UserProperties实例可以自动注入到控制器中。

@EnableConfigurationProperties(value = https://www.it610.com/article/{UserProperties.class})@ConfigurationPropertiesScan(basePackageClasses = {UserProperties.class})

而@ConfigurationPropertiesScan注解还可以指定要被扫描的包数组。

@ConfigurationPropertiesScan(basePackages = {"com.kaven.springboot.config"})

启动应用，访问http://localhost:8080/config。

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效果符合预期。
【SpringBoot中@ConfigurationProperties实现配置自动绑定的方法】
构造器绑定 Spring Boot将配置文件中的配置自动绑定到配置类，无非就是通过反射等手段，创建配置类实例，而配置项需要绑定到配置类实例的属性，这一般通过属性的set方法或者构造器来实现，上面的演示是通过set方法来进行绑定，这是@Setter注解的效果。

@Setter

如果需要通过构造器将配置项绑定到配置类实例的属性，可以使用@ConstructorBinding注解。

package com.kaven.springboot.config; import lombok.ToString; import org.springframework.boot.context.properties.ConfigurationProperties; import org.springframework.boot.context.properties.ConstructorBinding; import java.util.List; import java.util.Map; import java.util.Set; @ConfigurationProperties(prefix = "user")@ToString@ConstructorBindingpublic class UserProperties {private String username; private String password; private Set hobbies; private Map scores; private List userToken; public UserProperties(String username,String password,Set hobbies,Map scores,List userToken) {this.username = username; this.password = password; this.hobbies = hobbies; this.scores = scores; this.userToken = userToken; }}

使用@ConstructorBinding注解修饰类的问题在于类中可能有多个构造器，如果出现这种情况就会有问题。

package com.kaven.springboot.config; import lombok.ToString; import org.springframework.boot.context.properties.ConfigurationProperties; import org.springframework.boot.context.properties.ConstructorBinding; import java.util.List; import java.util.Map; import java.util.Set; @ConfigurationProperties(prefix = "user")@ToString@ConstructorBindingpublic class UserProperties { private String username; private String password; private Set hobbies; private Map scores; private List userToken; public UserProperties() {} public UserProperties(String username, String password, Set hobbies, Map scores, List userToken) { this.username = username; this.password = password; this.hobbies = hobbies; this.scores = scores; this.userToken = userToken; }}

因为Spring Boot不知道调用哪个构造器。

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可以将@ConstructorBinding注解修饰在构造器上。

package com.kaven.springboot.config; import lombok.ToString; import org.springframework.boot.context.properties.ConfigurationProperties; import org.springframework.boot.context.properties.ConstructorBinding; import java.util.List; import java.util.Map; import java.util.Set; @ConfigurationProperties(prefix = "user")@ToStringpublic class UserProperties {private String username; private String password; private Set hobbies; private Map scores; private List userToken; public UserProperties() {}@ConstructorBindingpublic UserProperties(String username,String password,Set hobbies,Map scores,List userToken) {this.username = username; this.password = password; this.hobbies = hobbies; this.scores = scores; this.userToken = userToken; }}

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结合@PropertySource SourceConfig类：

package com.kaven.springboot.config; import org.springframework.context.annotation.Configuration; import org.springframework.context.annotation.PropertySource; @Configuration@PropertySource(value = "https://www.it610.com/article/classpath:/static/user.properties")public class SourceConfig {}