在Spring Boot中使用 @ConfigurationProperties 和 @EnableConfigurationProperties

Spring Boot 使用一些轻松的规则来绑定属性到

@ConfigurationProperties

 bean 并且支持分层结构（hierarchical structure）。
开始创建一个

@ConfigurationProperties

 bean:

[code]@ConfigurationProperties(locations = "classpath:mail.properties", ignoreUnknownFields = false, prefix = "mail")
public class Mai
4000
lProperties {
private String host;
private int port;
private String from;
private String username;
private String password;
private Smtp smtp;

// ... getters and setters

@Override
public String toString() {
return "MailProperties [host=" + host + ", port=" + port + ", from=" + from + ", username=" + username
+ ", password=" + password + ", smtp=" + smtp + "]";
}

public static class Smtp {
private boolean auth;
private boolean starttlsEnable;

// ... getters and setters

}
}

创建mail.properties：

[code]mail.host=localhost
mail.port=25
mail.smtp.auth=false
mail.smtp.starttls-enable=false
mail.from=me@localhost
mail.username=duan
mail.password=duan123456

上例中我们用

@ConfigurationProperties

注解就可以绑定属性了。

ignoreUnknownFields = false

告诉Spring Boot在有属性不能匹配到值的时候抛出异常。开发的时候很方便! 

prefix

 用来选择哪个属性的prefix名字来绑定。
请注意setters 和 getters 需要在

@ConfigurationProperties

 bean中创建! 与

@Value

注解相反。

方案1:@Component + @ConfigurationProperties

[code]package com.dxz.property3;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

@Component
@ConfigurationProperties(locations = "classpath:mail.properties", ignoreUnknownFields = false, prefix = "mail")
public class MailProperties {
private String host;
private int port;
private String from;
private String username;
private String password;
private Smtp smtp;

// ... getters and setters

@Override
public String toString() {
return "MailProperties [host=" + host + ", port=" + port + ", from=" + from + ", username=" + username
+ ", password=" + password + ", smtp=" + smtp + "]";
}

public static class Smtp {
private boolean auth;
private boolean starttlsEnable;

}
}

启动及测试类：

[code]package com.dxz.property3;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
@SpringBootApplication
public class TestProperty3 {

@Autowired
private MailProperties mailProperties;

@RequestMapping(value = "/hello", method = RequestMethod.GET)
@ResponseBody
public String hello() {
System.out.println("mailProperties" + mailProperties);
return "hello world";
}

public static void main(String[] args) {
//SpringApplication.run(TestProperty1.class, args);
new SpringApplicationBuilder(TestProperty3.class).web(true).run(args);

}
}

结果：

[code]mailPropertiesMailProperties [host=localhost, port=25, from=me@localhost, username=duan, password=duan123456, smtp=com.dxz.property3.MailProperties$Smtp@37cebacb]

方案2：@Bean + @ConfigurationProperties

我们还可以把@ConfigurationProperties直接定义在@bean的注解上，这时bean实体类就不用@Component和@ConfigurationProperties了

[code]package com.dxz.property4;

public class MailProperties {
private String host;
private int port;
private String from;
private String username;
private String password;
private Smtp smtp;

// ... getters and setters

@Override
public String toString() {
return "MailProperties [host=" + host + ", port=" + port + ", from=" + from + ", username=" + username
+ ", password=" + password + ", smtp=" + smtp + "]";
}

public static class Smtp {
private boolean auth;
private boolean starttlsEnable;

}
}

启动类：

[code]@SpringBootApplication
public class TestProperty4 {

@Bean
@ConfigurationProperties(locations = "classpath:mail.properties", prefix = "mail")
public MailProperties mailProperties(){
MailProperties mp = new MailProperties();
System.out.println("zheli " + mp);
return mp;

}

public static void main(String[] args) {
//SpringApplication.run(TestProperty1.class, args);
new SpringApplicationBuilder(TestProperty4.class).web(true).run(args);

}
}

测试类：

[code]@RestController
@RequestMapping("/task")
public class TaskController {

@Autowired
MailProperties mailProperties;

@RequestMapping(value = {"/",""})
public String hellTask(){
System.out.println("mailProperties" +mailProperties);
return "hello task !!";
}

}

结果：

方案3:@ConfigurationProperties + @EnableConfigurationProperties

我们和上面例子一样注解属性，然后用 Spring的

@Autowire

来注入 mail configuration bean:

[code]@ConfigurationProperties(locations = "classpath:mail.properties", ignoreUnknownFields = false, prefix = "mail")
public class MailProperties {
private String host;
private int port;
private String from;
private String username;
private String password;
private Smtp smtp;

// ... getters and setters

@Override
public String toString() {
return "MailProperties [host=" + host + ", port=" + port + ", from=" + from + ", username=" + username
+ ", password=" + password + ", smtp=" + smtp + "]";
}

public static class Smtp {
private boolean auth;
private boolean starttlsEnable;

}
}

启动类及测试类：

[code]@RestController
@SpringBootApplication
@EnableConfigurationProperties(MailProperties.class)
public class TestProperty1 {

@Autowired
private MailProperties mailProperties;

@RequestMapping(value = "/hello", method = RequestMethod.GET)
@ResponseBody
public String hello() {
System.out.println("mailProperties" + mailProperties);
return "hello world";
}

public static void main(String[] args) {
//SpringApplication.run(TestProperty1.class, args);
new SpringApplicationBuilder(TestProperty1.class).web(true).run(args);

}
}

结果：

请注意

@EnableConfigurationProperties

注解。该注解是用来开启对@ConfigurationProperties注解配置Bean的支持。也就是@EnableConfigurationProperties注解告诉Spring Boot 能支持@ConfigurationProperties。如果不指定会看到如下异常:

[code]Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.dxz.property.MailProperties] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}