Spring Boot 自定义starter的示例代码
springboot 个人感觉特点:
1)众多库的集合(各种starter),方便快速构建应用系统。
2)自动配置spring(通过autoconfiguration机制),简化配置,也方便扩展新的starter。
3)内嵌web容器,无需war部署。
创建一个用maven构建的springboot项目
pom文件配置如下:
<?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.xjw.springboot</groupid> <artifactid>hellostarter</artifactid> <version>0.0.1-snapshot</version> <packaging>jar</packaging> <name>hello-spring-boot-starter</name> <description>测试自定义starter</description> <parent> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-parent</artifactid> <version>1.5.2.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</artifactid> </dependency> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-test</artifactid> <scope>test</scope> </dependency> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-configuration-processor</artifactid> <optional>true</optional> </dependency> </dependencies> <build> <plugins> <plugin> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-maven-plugin</artifactid> </plugin> </plugins> </build> </project>
定义一个pojo用来接收properties中配置的信息
package com.xjw; import org.springframework.boot.context.properties.configurationproperties; @configurationproperties(prefix = "hello") public class helloserviceproperteis { private string msg; public string getmsg() { return msg; } public void setmsg(string msg) { this.msg = msg; } }
@configurationproperties:用来标识这个pojo是一个用来接收指定前缀的资源配置值
prefix:表示在配置文件中配置项前缀[/code]
编写一个service用来对外提供服务
package com.xjw; 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; } }
配置一个pojo用来读取上面配置的helloserviceproperteis
package com.xjw; 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; @configuration @enableconfigurationproperties(value = helloserviceproperteis.class) @conditionalonclass(helloservice.class) @conditionalonproperty(prefix = "hello", value = "enable", matchifmissing = true) public class helloautoconfiguration { @autowired private helloserviceproperteis helloserviceproperteis; @bean @conditionalonmissingbean(helloservice.class) public helloservice helloservice() { helloservice helloservice = new helloservice(); helloservice.setmsg(helloserviceproperteis.getmsg()); return helloservice; } }
@configuration:标识此类为一个spring配置类
@enableconfigurationproperties(value = helloserviceproperteis.class):启动配置文件,value用来指定我们要启用的配置类,可以有多个,多个时我们可以这么写value={xxproperties1.class,xxproperteis2.class....}
@conditionalonclass(helloservice.class):表示当classpath下存在helloservice.class文件时改配置文件类才有效
@conditionalonproperty(prefix = "hello", value = "enable", matchifmissing = true):表示只有我们的配置文件是否配置了以hello为前缀的资源项值,并且在该资源项值为enable,如果没有配置我们默认设置为enable[/code]
最后在src/main/resources 文件夹下新建文件夹 meta-inf,在新建的meta-inf文件夹下新建spring.factories
在新建的spring.factories文件中配置自动启动类为我们之前编写的helloautoconfiguration 类
org.springframework.boot.autoconfigure.enableautoconfiguration=com.xjw.helloautoconfiguration
然后就可以在其他的spring-boot项目中使用我们刚刚新建的starter了,我们来测试一下
在新建一个spring-boot项目,pom.xml配置如下:
<?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.xjw.springboot</groupid> <artifactid>hellostarter.test</artifactid> <version>0.0.1-snapshot</version> <packaging>jar</packaging> <name>hello-spring-boot-starter-test</name> <description>测试自定义starter</description> <parent> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-parent</artifactid> <version>1.5.2.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-web</artifactid> </dependency> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-test</artifactid> <scope>test</scope> </dependency> <dependency> <groupid>com.xjw.springboot</groupid> <artifactid>hellostarter</artifactid> <version>0.0.1-snapshot</version> </dependency> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-devtools</artifactid> </dependency> </dependencies> <build> <plugins> <plugin> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-maven-plugin</artifactid> </plugin> </plugins> </build> </project>
然后我们直接在咋们的启动类中中尝试使用以下我们上面定义的starter提供的helloservice:
package com.xjw; import org.springframework.beans.factory.annotation.autowired; import org.springframework.boot.springapplication; import org.springframework.boot.autoconfigure.springbootapplication; import org.springframework.web.bind.annotation.requestmapping; import org.springframework.web.bind.annotation.restcontroller; @restcontroller @springbootapplication public class hellospringbootstartertestapplication { @autowired private helloservice helloservice; @requestmapping("/") public string index() { return helloservice.sayhello(); } public static void main(string[] args) { springapplication.run(hellospringbootstartertestapplication.class, args); } }
接着我们修改测试项目中的application.properteis,加入如下配置:
debug=true server.port=8888 #hello=enable hello.msg=测试starter
最后启动项目,观察控制台输出的内容中依赖的starter,从positive matches下我们可以看到有这么一句:
helloautoconfiguration matched:
- @conditionalonclass found required class 'com.xjw.helloservice'; @conditionalonmissingclass did not find unwanted class (onclasscondition)
- @conditionalonproperty (hello.enable) matched (onpropertycondition)
或者我们打开项目依赖树也能找到我们的starter ,这说明spring已经自动的启动了我们的starter了,打开浏览器输入地址:http://localhost:8888/将会看到如下结果
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。
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