開發自定義的Spring-Boot-Starter

 

starter命名規範

spring提供的starter：

• spring-boot-starter-xxx-x.y.z.jar
• spring-boot-xxx-autoconfigure-x.y.z.jar

第三方提供的starter：

• xxx-spring-boot-starter-x.y.z.jar

 

動手製作自定義Spring-Boot-Starter的步驟

1、新建項目，引入依賴

引入spring-boot-starter、spring-boot-autoconfigure、第三方jar，如果需要生成配置元信息，加入spring-boot-configuration-processor

2、編寫功能實現類

3、編寫自動配置類

4、在resources/META-INF/spring.factories中配置自動裝配類

5、打包

 

這裏我們使用jsoup抓取網頁信息爲例，製作一個starter。

項目結構：

1、新建maven項目，引入依賴：

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath /> 
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>org.jsoup</groupId>
            <artifactId>jsoup</artifactId>
            <version>1.11.3</version>
        </dependency>


    </dependencies>

 

2、編寫功能實現類

編寫實現抓取網頁內容的類

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;

public class CrawlPageClient {

    private String pageUrl;

    private CrawlPageClient() {
    }

    public CrawlPageClient(String pageUrl) {
        this.pageUrl = pageUrl;
    }

    public static CrawlPageClient of(String pageUrl) {
        return new CrawlPageClient(pageUrl);
    }

    public String getPageUrl() {
        return pageUrl;
    }

    public PageInfo getPageInfo() {
        PageInfo pageInfo = new PageInfo();
        try {
            Document doc = Jsoup.connect(pageUrl).get();
            pageInfo.setUrl(pageUrl);
            pageInfo.setTitle(doc.title());
            pageInfo.setContent(doc.html());
            return pageInfo;
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }
}

 

網頁信息類

public class PageInfo {
    private String url;
    private String title;
    private String content;

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public String getTitle() {
        return title;
    }

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

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }
}

 

3、編寫自動配置類

import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableConfigurationProperties( {PageProperties.class })
public class CrawlAutoConfigure {

    @Bean
    public CrawlPageClient create(PageProperties pageProperties) {
        return CrawlPageClient.of(pageProperties.getPageUrl());
    }
}

頁面配置類，配置前綴：crawl

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

@ConfigurationProperties(prefix = PageProperties.CRAWL_PREFIX)
public class PageProperties {

    public static final String CRAWL_PREFIX = "crawl";

    private String pageUrl = "http://www.baidu.com";

    public String getPageUrl() {
        return pageUrl;
    }

    public void setPageUrl(String pageUrl) {
        this.pageUrl = pageUrl;
    }
}

默認抓取百度的頁面內容

 

4、在resources/META-INF/spring.factories中配置自動裝配類

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.lee.springboot.CrawlAutoConfigure

 

5、打包

打成jar包: crawl-spring-boot-starter-1.0.jar，maven依賴信息：

<dependency>
            <groupId>org.lee.springboot</groupId>
            <artifactId>crawl-spring-boot-starter</artifactId>
            <version>1.0</version>
        </dependency>

 

測試自定義starter

最後，新建測試項目測試自定義的starter。

引入依賴：

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath />
    </parent>

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

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

        <!-- spring-boot crawl -->
        <dependency>
            <groupId>org.lee.springboot</groupId>
            <artifactId>crawl-spring-boot-starter</artifactId>
            <version>1.0</version>
        </dependency>

    </dependencies>

 

新建測試類：

import org.lee.springboot.CrawlPageClient;
import org.lee.springboot.PageInfo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("crawl")
public class CrawlController {

    @Autowired
    private CrawlPageClient crawlPageClient;

    @GetMapping("")
    @ResponseBody
    public PageInfo crawlPageInfo() {
        StringBuilder pageBuilder = new StringBuilder();
        pageBuilder.append("抓取到").append(crawlPageClient.getPageUrl())
                .append("網頁的信息<br/>").append(crawlPageClient.getPageInfo());
        System.out.println(crawlPageClient.getPageInfo());
        return crawlPageClient.getPageInfo();
    }
}

運行程序，瀏覽器輸入：http://127.0.0.1:8080/crawl

默認看到的是百度網頁的信息：

 

我們在application.properties配置中加入以下配置：

crawl.page-url=https://www.csdn.net

抓取網頁改成csdn的，再次運行程序，訪問內容如下：

 

總結

本文簡單介紹如何開發自定義的Spring-Boot-Starter，通過添加依賴自動完成功能導入，使用起來很方便，大家也可以自己動手實現自定義的starter。