在我們使用SpringBoot以及SpringCloud的一系列組件(比如說Eureka)的時(shí)候，我們都是只需要添加注解@Enablexxx就可以引入對應(yīng)的模塊(對于EurekaServer僅需使用@EnableEurekaServer注解)，非常方便快捷拆座。這其實(shí)對于我們抽取一些通用的功能非常有利霜运，避免了每次都要寫或者復(fù)制同樣的代碼代乃，提高開發(fā)效率办龄。
在探究原理之后，我做了一個(gè)自己的實(shí)現(xiàn)敌卓。我們來看一下使用效果：

使用效果圖.png

運(yùn)行效果圖.gif

我們來探究一下原理實(shí)現(xiàn)：
首先介紹一下Spring的JavaBean注解：
@Component
@Controller
@Service
@Configuration
@Import
@ImportResource
@Bean
此次略過介紹，有空再補(bǔ)
1. 創(chuàng)建一個(gè)Admin模塊項(xiàng)目(SpringBoot項(xiàng)目)荸哟，pom.xml如下

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.sanisy</groupId>
    <artifactId>admin-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>admin-demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-freemarker</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-source-plugin</artifactId>
                <version>2.2.1</version>
            </plugin>
        </plugins>
    </build>
</project>

項(xiàng)目目錄結(jié)構(gòu)如下

Admin模塊整體結(jié)構(gòu).png

package com.sanisy.controller;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

/**
 * Created by Sanisy on 2018/4/30.
 */
@Slf4j
@Controller
@RequestMapping(value = "/admin/login")
public class LoginController {

    /**
     * 登錄頁
     */
    @Value("${login.page}")
    private String loginPage;

    /**
     * 登錄頁
     * @return
     */
    @RequestMapping(value = "/page")
    public String loginPage() {
        log.info("This is login page:{}", loginPage);
        return loginPage;
    }

    /**
     * 用戶登錄
     * @param userName
     * @param password
     * @return
     */
    @RequestMapping(value = "/login", method = RequestMethod.POST)
    @ResponseBody
    public String login(String userName, String password) {
        if (!"admin".equals(userName) || !"123456".equals(password)) {
            log.info("login fail,userName={},password={}", userName, password);
            return "login fail:userName or password error!!!";
        }

        return "login success, welcome to come here!";
    }
}

AdminAutoConfiguration代碼

package com.sanisy.annotations;

import org.springframework.context.annotation.ComponentScan;

/**
 * Created by Sanisy on 2018/5/1.
 */
@ComponentScan(basePackages =
        {
                "com.sanisy",
                "com.sanisy.controller",
        })
public class AdminAutoConfiguration {
}

EnableAdminDemo代碼

package com.sanisy.annotations;

import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Created by Sanisy on 2018/4/30.
 */
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@Configuration
@Import(AdminAutoConfiguration.class)
public @interface EnableAdminDemo {

}

以上代碼完成后執(zhí)行maven命令：

1.將項(xiàng)目打包成jar包：mvn clean install
2.將jar包部署到本地maven倉庫：mvn install:install-file -Dfile=E:\Study\Workspaces\Idea\admin-demo\target\admin-demo-0.0.1-SNAPSHOT.jar -DgroupId=com.sanisy -DartifactId=admin-demo -Dversion=2.0.2 -Dpackaging
=jar

2. 使用Admin模塊
創(chuàng)建一個(gè)新的SpringBoot項(xiàng)目(這里是enable-demo)假哎，pom.xml文件如下

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.dodo</groupId>
    <artifactId>enable-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>enable-demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-freemarker</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <!--引入Admin模塊依賴-->
        <dependency>
            <groupId>com.sanisy</groupId>
            <artifactId>admin-demo</artifactId>
            <version>2.0.2</version>
        </dependency>
    </dependencies>

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

工程目錄結(jié)構(gòu)如下

enable-demo目錄結(jié)構(gòu).png

package com.dodo;

import com.sanisy.annotations.EnableAdminDemo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@EnableAdminDemo
public class EnableDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(EnableDemoApplication.class, args);
    }
}