spring boot 自定义starter的实现教程

spring boot 使用 starter 解决了很多配置问题, 但是, 他是怎么来解决这些问题的呢?

这里通过一个简单的例子, 来看一下, starter是怎么来设置默认配置的.

一. 建 starter 项目

自定义的starter, 项目命名规范是： 自定义名-spring-boot-starter

先来看一下, 我最后的目录结构

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>

其实只是加入了 spring-boot-autoconfigure

app文件中的main方法, 我注释掉了, 这个在这里没有用到

2. 配置属性对应的接收文件

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 {
 //默认配置内容
 private static final string msg = "world";
 private string msg = msg;
 public string getmsg() {
 return msg;
 }
 public void setmsg(string msg) {
 this.msg = msg;
 }
}

3. 对外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. 对外service与配置对应文件关联

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

做完这些之后, 通过 mvn clean install , 打包到maven库里面

二. spring boot 项目使用

新建一个spring boot 项目, 选择web即可.

目录结构：

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();
 }
}

这里的 helloservice 就是 前面自定义 starter 里面的.

1. 结果: 未配置情况下, 应该是输出 hello world

2. 在配置文件中, 加入 hello.msg=hahahahahah

这个例子很简单, 只是显示一下主要的过程, 别的都是各插件自己的逻辑判断了.

参考资料：

javaee开发的颠覆者 spring boot实战

以上这篇spring boot 自定义starter的实现教程就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持。