Spring Boot 自定义starter

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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

 1 package com.xjw;                                                                                                           2                                                                                                                            3 import org.springframework.boot.context.properties.ConfigurationProperties;                                                4                                                                                                                            5 @ConfigurationProperties(prefix = "hello")                                                                                 6 public class HelloServiceProperteis {                                                                                      7                                                                                                                            8     private String msg;                                                                                                    9                                                                                                                           10     public String getMsg() {                                                                                              11         return msg;                                                                                                       12     }                                                                                                                     13                                                                                                                           14     public void setMsg(String msg) {                                                                                      15         this.msg = msg;                                                                                                   16     }                                                                                                                     17                                                                                                                           18 }                                                                                                                         19

@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

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

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@SpringBootApplicationpublic 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=trueserver.port=8888#hello=enablehello.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

转自： http://www.cnblogs.com/cz-xjw/p/6632402.html

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