前言

Srping自动装配非常实用，我们可以利用这个把项目解耦合，真正使用的只需引入即可使用。
今天我们来演示下自动装配，利用自动装配，实现web拦截器，解析request中的内容。

项目搭建

引入需要的pom

<dependencies>                                              
    <dependency>                                            
        <groupId>org.projectlombok</groupId>                
        <artifactId>lombok</artifactId>                     
        <version>1.18.24</version>                          
    </dependency>                                           
                                                            
    <dependency>                                            
        <groupId>org.springframework.boot</groupId>         
        <artifactId>spring-boot-autoconfigure</artifactId>  
        <version>2.7.0</version>                            
    </dependency>                                           
    <dependency>                                            
        <groupId>org.springframework</groupId>              
        <artifactId>spring-webmvc</artifactId>              
        <version>5.3.20</version>                           
    </dependency>                                           
    <dependency>                                            
        <groupId>javax.servlet</groupId>                    
        <artifactId>javax.servlet-api</artifactId>          
        <version>4.0.1</version>                            
        <scope>provided</scope>                             
    </dependency>                                           
                                                            
    <!-- json -->                                           
    <dependency>                                            
        <groupId>com.alibaba</groupId>                      
        <artifactId>fastjson</artifactId>                   
        <version>2.0.3</version>                            
    </dependency>                                           
</dependencies>                                             

编写拦截器

import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author sxt
 * @date 2022-07-01
 * @describe header拦截器
 */
public class HeaderInterceptor implements HandlerInterceptor {
    private final static String OPTIONS = "OPTIONS";

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("处理request");
        return true;
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("后置处理");
    }
}

web配置

import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * @author sxt
 * @date 2022-07-01
 * @describe web配置
 */
@Order(Ordered.HIGHEST_PRECEDENCE)
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new HeaderInterceptor());
    }
}

自动装配配置类

import com.yqsl.config.header.WebConfig;
import org.springframework.context.annotation.Import;


/**
 * @author sxt
 * @date 2022-07-01
 * @describe 自动配置
 */
@Import(WebConfig.class)
public class HeaderAutoConfiguration {
}

在/resource/META-INF/spring.factories中添加类路径

org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.yqsl.config.HeaderAutoConfiguration

上传jar包

此时需要注意，直接打包有可能打包失败，需要把pom中内容删掉

<build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

打成jar包，上传到云仓库中，项目引入对应jar，就可以直接使用了。