spring boot 自定義starter的實現教程

spring boot 使用starter 解決了很多配置問題, 但是, 他是怎麼來解決這些問題的呢?

這里通過一個簡單的例子, 來看一下, starter是怎麼來設置默認配置的.

一. 建starter 項目

自定義的starter, 項目命名規範是： 自定義名-spring-boot-starter

先來看一下, 我最後的目錄結構

1. 修改pom.xml文件

<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>org.elvin</groupId> <artifactId>my-spring-boot-starter</artifactId> <version>1.0-SNAPSHOT</version> <packaging>jar</packaging> <name>my-spring-boot-starter</name> <url>http://maven.apache.org</url> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-autoconfigure</artifactId> <version>1.5.9.RELEASE</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>2.3.2</version> <configuration> <source>1.8</source> <target>1.8</target> </configuration> </plugin> </plugins> </build></project>

其實只是加入了spring-boot-autoconfigure

App文件中的main方法, 我註釋掉了, 這個在這裡沒有用到

2. 配置屬性對應的接收文件

package org.elvin;import org.springframework.boot.context.properties.ConfigurationProperties;/** * author: Elvin * Date: 2017/12/12 14:51 * Description: */@ConfigurationProperties(prefix = "hello")public class HelloServiceProperties { //默認配置內容private static final String MSG = "world"; private String msg = MSG; public String getMsg() { return msg; } public void setMsg(String msg) { this.msg = msg; }}

3. 對外Service

 package org.elvin;/** * author: Elvin * Date: 2017/12/12 14:55 * Description: */public class HelloService { private String msg; public String sayHello(){ return "Hello " + msg; } public String getMsg() { return msg; } public void setMsg(String msg) { this.msg = msg; }}

4. 對外service與配置對應文件關聯

package org.elvin;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;import org.springframework.boot.context.properties.EnableConfigurationProperties;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;/** * author: Elvin * Date: 2017/12/12 14:59 * Description: */@Configuration@EnableConfigurationProperties(HelloServiceProperties.class)@ConditionalOnClass(HelloService.class)@ConditionalOnProperty(prefix = "hello", value="enabled", matchIfMissing =true )public class HelloServiceAutoConfiguration { @Autowired private HelloServiceProperties helloServiceProperties; @Bean @ConditionalOnMissingBean(HelloService.class) public HelloService helloService(){ HelloService helloService = new HelloService(); helloService.setMsg(helloServiceProperties.getMsg()); return helloService; }}

5. starter配置: spring.factories

 org.springframework.boot.autoconfigure.EnableAutoConfiguration=org.elvin.HelloServiceAutoConfiguration

做完這些之後, 通過mvn clean install , 打包到maven庫裡面

二. spring boot 項目使用

新建一個spring boot 項目, 選擇web即可.

目錄結構：

先看一下引用pom.xml

 <dependency> <groupId>org.elvin</groupId> <artifactId>my-spring-boot-starter</artifactId> <version>1.0-SNAPSHOT</version> </dependency>

再看一下HelloController

 package org.elvin.learn.springboot.controller;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import org.elvin.*;/** * author: Elvin * Date: 2017/12/12 15:34 * Description: */@RestController@RequestMapping("hello")public class HelloController { @Autowired private HelloService helloService; @RequestMapping("index") public String index(){ return helloService.sayHello(); }}

這裡的HelloService 就是前面自定義starter 裡面的.

1. 結果: 未配置情況下, 應該是輸出hello world

2. 在配置文件中, 加入hello.msg=hahahahahah

這個例子很簡單, 只是顯示一下主要的過程, 別的都是各插件自己的邏輯判斷了.

參考資料：

JavaEE開發的顛覆者Spring Boot實戰

以上這篇spring boot 自定義starter的實現教程就是小編分享給大家的全部內容了，希望能給大家一個參考，也希望大家多多支持武林網。