在Spring Boot中，自定义属性是一种非常常见的需求，通常用于配置应用程序的行为。以下是Spring Boot中自定义属性的几种常见方式：

一、使用 @Value 注解注入单个属性

1.在 application.properties 或 application.yml 中定义属性

#配置自定义属性W3cjavaProperties
w3cjava:
  blog:
    name: w3cjava‘blog
    desc: w3cjava’blog description
    #属性间引用
    title: ${w3cjava.blog.name}---${w3cjava.blog.desc}

2.通过 @Value 注解将属性值注入到字段中：

@Component
public class CustomProperties {
    @Value("${w3cjava.blog.name}")
    private String name;
    @Value("${w3cjava.blog.desc}")
    private String desc;
    @Value("${w3cjava.blog.title}")
    private String title;

    public String getDesc() {
        return desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }


    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

3.测试效果

在IndexController中注入

@RestController
@RequestMapping("/index")
public class IndexController {
    @Autowired
    private CustomProperties customProperties;
    @RequestMapping("/custom-properties")
    public String customProperties() {
        return customProperties.getName() + ":" + customProperties.getDesc() + ":" + customProperties.getTitle();
    }
}

启动项目，访问路径

http://localhost:8081/index/custom-properties

二、@ImportResource外部引入xml文件配置

1.配置xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
            http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

    <bean id="xmlBeanTest" class="com.w3cjava.modules.index.bean.XmlBeanTest">
        <property name="name" value="w3cjava"></property>
    </bean>
</beans>

2.编写ConfigClass注入配置文件xml

@Configuration
@ImportResource(locations = {"classpath:w3cjava-application.xml"})
public class XmlConfig {
}

3.自定义xml对应的实体类

public class XmlBeanTest {
    private String name;


    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

4.测试controller

    @Autowired
    private XmlBeanTest xmlBeanTest;  
    //自定义配置文件echoplots.properties Test
    @RequestMapping("/xml")
    public String xml() {
        return xmlBeanTest.getName();
    }

5.启动项目测试xml配置效果

访问

http://localhost:8081/index/xml

三、@ConfigurationProperties(prefix = "w3cjava.blog") 引入多自定义属性配置

1.创建引入properties对应实体Bean

这里要注意，通过@ConfigurationProperties(prefix = "w3cjava.blog")配置前置

@ConfigurationProperties(prefix = "w3cjava.blog")
public class ConfigurationPropertiesBeans {
    private String name;
    private String desc;
    private String title;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDesc() {
        return desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }
}

2.项目启动类，通过@EnableConfigurationProperties(ConfigurationPropertiesBeans.class)启用

@SpringBootApplication
@EnableConfigurationProperties(ConfigurationPropertiesBeans.class)
public class SpringBootConfigApplication {
    public static void main(String[] args) {
        SpringApplication.run(SpringBootConfigApplication.class, args);
    }
}

3.测试controller

 @Autowired
    private ConfigurationPropertiesBeans configurationPropertiesBeans;
    //多自定义属性Test
    @RequestMapping("/bean")
    public String indexBean() {
        return configurationPropertiesBeans.getName()+"###" +configurationPropertiesBeans.getDesc();
    }


    //属性间引用Test
    @RequestMapping("/title")
    public String title() {
        return configurationPropertiesBeans.getTitle();
    }

分别访问，测试效果

http://localhost:8081/index/bean

http://localhost:8081/index/title

四、通过引入外部自定义properties

1.创建外部w3cjava.properties文件，定义变量

w3cjava.name = echoplots
w3cjava.age = 28

2.创建对应实体配置类，添加配置

• @Configuration或者@Component 注入
• @ConfigurationProperties(prefix="w3cjava") 指定配置文件前缀
• @PropertySource("classpath:w3cjava.properties") 指明使用的配置文件

/**
 * @Author cos
 * @description 通过引入外部properties自定义配置
 */
@Configuration
// 指定配置文件前缀
@ConfigurationProperties(prefix="w3cjava")
// 指明使用的配置文件
@PropertySource("classpath:w3cjava.properties")
@Component
public class W3cjavaConfigBean {
    private String name;
    private Integer age;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
  
}

3.项目启动类，通过@EnableConfigurationProperties(W3cjavaConfigBean.class)启用

4.测试controller

    @Autowired
    private W3cjavaConfigBean w3cjavaConfigBean;
    @RequestMapping("/properties")
    public String properties() {
        return "姓名："+w3cjavaConfigBean.getName()+" 年龄："+w3cjavaConfigBean.getAge();
    }

访问

http://localhost:8081/index/properties

五、小结

通过以上4种不同方式，自定义属性，可以根据项目需求采用不同配置方式。

六、源码地址

05-spring-boot-config