SpringBoot自学好几天中途开始写笔记自定义starter 20190224

自定义starter

starter:
1. 这个场景使用的依赖是什么（jar包）
2. 如何编写自动配置参考WebMvcAutoConfiguration.java
SpringBoot自学好几天中途开始写笔记自定义starter 20190224

@Configuration  //指定这个类是配置类
@ConditionalOnXXX //在条件成立的情况下 生效
@AutoConfigureOrder //指定自动配置类的顺序 
@AutoConfigureAfter //指定自动配置类在哪个类加载之后
@Bean //给容器中添加组件 
@ConfigurationProperties结合相关的xxxProperties类 来绑定相关的配置
@EnableConfigurationProperties //让xxxProperties 类生效 并加入到容器中

自动配置类要能加载 必须把自动配置类指定在类路径下/META-INF/spring.factories
# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\
org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\
org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration,\
org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration,\
org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration,\
org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration,\
org.springframework.boot.autoconfigure.cloud.CloudServiceConnectorsAutoConfiguration,\
org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration,\
org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration,\
org.springframework.boot.autoconfigure.couchbase.CouchbaseAutoConfiguration,\

模式

启动器只用来做依赖导入，
专门写一个自动配置模块
启动器依赖自动配置模块
别人只需要引入启动器（starter）
当然：也可以都写到启动器里边
约定名称：

mybatis-spring-boot-starter : 自动以启动器名+spring-boot-starter

创建工程
自动配置Modules
再创建一个模块自动配置相关的东西
example-springboot-starter pom.xml 引入我们的example-springboot-starter-autoconfigure

<?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.example.starter</groupId>
    <artifactId>example-springboot-starter</artifactId>
    <version>1.0-SNAPSHOT</version>
    <!--启动器-->
    <dependencies>
        <!--引入自动配置-->
        <dependency>
            <groupId>com.example.starter</groupId>
            <artifactId>example-springboot-starter-autoconfigure</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>
    </dependencies>
    
</project>

自动配置没用的模块删掉

pom.xml 中的test也不要了插件也不要了

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example.starter</groupId>
    <artifactId>example-springboot-starter-autoconfigure</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>example-springboot-starter-autoconfigure</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
       <!--引入spring-boot-starter;所有starter的基本配置-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

       
    </dependencies>

 

</project>

编写类

HelloProperties 属性映射

package com.example.starter;

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

/**
 * @author LM
 * @create 2019-02-24 10:17
 */
//绑定配置文件中以example.hello 开头的所有属性
@ConfigurationProperties(prefix = "example.hello")
public class HelloProperties {
    private String  prefix;
    private  String suffix;

    public String getPrefix() {
        return prefix;
    }

    public void setPrefix(String prefix) {
        this.prefix = prefix;
    }

    public String getSuffix() {
        return suffix;
    }

    public void setSuffix(String suffix) {
        this.suffix = suffix;
    }
}

HelloService类方法使用到属性文件的属性

package com.example.starter;

/**
 * @author LM
 * @create 2019-02-24 10:16
 */
public class HelloService {

    HelloProperties helloProperties;


    public HelloProperties getHelloProperties() {
        return helloProperties;
    }

    public void setHelloProperties(HelloProperties helloProperties) {
        this.helloProperties = helloProperties;
    }

    public String  sayHello(String name){
        //从配置中拿属性
        return helloProperties.getPrefix()+ name +helloProperties.getSuffix();
    }
}

HelloServiceAutoConfiguration 自动配置类

package com.example.starter;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * @author LM
 * @create 2019-02-24 10:22
 */
@Configuration
@ConditionalOnWebApplication
@EnableConfigurationProperties(HelloProperties.class)
public class HelloServiceAutoConfiguration {

    @Autowired
    HelloProperties helloProperties;

    @Bean
    public  HelloService helloService(){
        HelloService helloService = new HelloService();
        helloService.setHelloProperties(helloProperties);
        return helloService;
    }
}

spring.factories 配置好这个才能！！生效

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.example.starter.HelloServiceAutoConfiguration

有报错把test文件夹也删了

example-springboot-starter-autoconfigure 安装到仓库

可能会报错：Execution default of goal org.springframework.boot:spring-boot-maven-plugin:1.5.6.RELEASE:repackage failed: Unable to find main class
修改pom.xml 去掉插件引用就好了

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example.starter</groupId>
    <artifactId>example-springboot-starter-autoconfigure</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>example-springboot-starter-autoconfigure</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

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


    </dependencies>



</project>

SpringBoot自学好几天中途开始写笔记自定义starter 20190224
11. example-springboot-starter安装到仓库

测试创建项目
pom中引入依赖

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example.starter.test</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-boot-starter-test</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

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

        <!--引入自定义starter-->
        <dependency>
            <groupId>com.example.starter</groupId>
            <artifactId>example-springboot-starter</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

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

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

编写测试类

package com.example.starter.test.springboot.controller;

import com.example.starter.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author LM
 * @create 2019-02-24 21:48
 */
@RestController
public class HelloController  {
    @Autowired
    HelloService helloService;
    @GetMapping("/hello")
    public String hello() {
        return helloService.sayHello("测试");
    }
}

配置文件

example.hello.prefix=EXAMPLE
example.hello.suffix=HELLO

测试