SpringBoot注入配置文件的3种方法

方案1:@ConfigurationProperties+@Component

定义spring的一个实体bean装载配置文件信息，其它要使用配置信息是注入该实体bean

/**
 * 将配置文件中配置的每一个属性的值，映射到这个组件中
 * @ConfigurationProperties：告诉SpringBoot将本类中的所有属性和配置文件中相关的配置进行绑定；
 *      prefix = "person"：配置文件中哪个下面的所有属性进行一一映射
 *
 * 只有这个组件是容器中的组件，才能容器提供的@ConfigurationProperties功能；
 *
 */
@Component
@ConfigurationProperties(prefix = "person")
public class Person {
​
    private String lastName;
    private Integer age;
    private Boolean boss;
    private Date birth;
​
    private Map<String,Object> maps;
    private List<Object> lists;
    private Dog dog;

方案2：@Bean+@ConfigurationProperties

我们还可以把@ConfigurationProperties还可以直接定义在@bean的注解上，这是bean实体类就不用@Component和@ConfigurationProperties了，这边是Boot的动态数据源切换的类。

package com.topcheer.oss.base.datasource;
​
import com.alibaba.druid.pool.DruidDataSource;
​
import com.xiaoleilu.hutool.crypto.symmetric.SymmetricAlgorithm;
import com.xiaoleilu.hutool.crypto.symmetric.SymmetricCrypto;
import com.xiaoleilu.hutool.util.CharsetUtil;
import com.xiaoleilu.hutool.util.HexUtil;
​
import lombok.extern.slf4j.Slf4j;
​
@Slf4j
public class UmspscDataSource extends DruidDataSource {
​
    private static final long serialVersionUID = 4766401181052251539L;
​
    private String passwordDis;
    
    /**
     * 密匙
     */
    private final static String Pkey ="1234565437892132";
    
    @Override
    public String getPassword() {
        if(passwordDis != null && passwordDis.length() > 0) {
            return passwordDis;
        }
        String encPassword = super.getPassword();
        if(null == encPassword) {
            return null;
        }
        log.info("数据库密码加解密，{" + encPassword + "}");
        try {
            //  密文解密，解密方法可以修改
            String key = HexUtil.encodeHexStr(Pkey);
            SymmetricCrypto aes = new SymmetricCrypto(SymmetricAlgorithm.AES, key.getBytes());
            passwordDis = aes.decryptStr(encPassword, CharsetUtil.CHARSET_UTF_8);
            return passwordDis;
        } catch (Exception e) {
            log.error("数据库密码解密出错，{"+encPassword + "}");
            //log.error(LogUtil.e(e));
            //throw new Exception("数据库密码解密失败！", e);
            return null;
        }
    }
​
}

@Bean(name = "systemDataSource")
    @ConfigurationProperties(ignoreUnknownFields = false, prefix = "spring.datasource.system")
    public DataSource systemDataSource() {
        return new UmspscDataSource();
    }
​
    @Bean(name = "secondDataSource")
    @ConfigurationProperties(ignoreUnknownFields = false, prefix = "spring.datasource.second")
    public DataSource secondDataSource() {
        return new UmspscDataSource();
    }
    
    @Bean(name="systemJdbcTemplate")
    public JdbcTemplate systemJdbcTemplate(
            @Qualifier("systemDataSource") DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }
    
    @Bean(name="secondJdbcTemplate")
    public JdbcTemplate secondJdbcTemplate(
            @Qualifier("secondDataSource") DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }

​

 

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:

package com.dxz.property;
​
import org.springframework.boot.context.properties.ConfigurationProperties;
​
@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
    public String getHost() {
        return host;
    }
​
    public void setHost(String host) {
        this.host = host;
    }
​
    public int getPort() {
        return port;
    }
​
    public void setPort(int port) {
        this.port = port;
    }
​
    public String getFrom() {
        return from;
    }
​
    public void setFrom(String from) {
        this.from = from;
    }
​
    public String getUsername() {
        return username;
    }
​
    public void setUsername(String username) {
        this.username = username;
    }
​
    public String getPassword() {
        return password;
    }
​
    public void setPassword(String password) {
        this.password = password;
    }
​
    public Smtp getSmtp() {
        return smtp;
    }
​
    public void setSmtp(Smtp smtp) {
        this.smtp = smtp;
    }
    
    @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;
​
        public boolean isAuth() {
            return auth;
        }
​
        public void setAuth(boolean auth) {
            this.auth = auth;
        }
​
        public boolean isStarttlsEnable() {
            return starttlsEnable;
        }
​
        public void setStarttlsEnable(boolean starttlsEnable) {
            this.starttlsEnable = starttlsEnable;
        }
​
    }
}

启动类及测试类：

package com.dxz.property;
​
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
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
@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:

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)}

注意: 还有其他办法 (Spring Boot 总是有其他办法!) 让@ConfigurationProperties beans 被添加 – 用@Configuration或者 @Component注解, 这样就可以在 component scan时候被发现了。

	@ConfigurationProperties	@Value
功能	批量注入配置文件中的属性	一个个指定
松散绑定（松散语法）	支持	不支持
SpEL	不支持	支持
JSR303数据校验	支持	不支持
复杂类型封装	支持	不支持

配置文件yml还是properties他们都能获取到值；

如果说，我们只是在某个业务逻辑中需要获取一下配置文件中的某项值，使用@Value；

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