Spring Boot 笔记 004 自动配置和自定义starter

003讲到了导入jar包中的方法，但其实是个半成品，别人写的jar包中的方法我要在自己的代码中去调用，非常的不方便。原则上写给别人用的jar包，人家要能直接用，而不用写注入的方法。

在springboot中会自动扫描imports文件中的内容，利用这一点进行自动注入的开发

以下是整个jar包的目录

Country

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package cn.itcast.pojo;

public class Country {
    private String name;
    private String system;

    public Country() {
    }

    public Country(String name, String system) {
        this.name = name;
        this.system = system;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSystem() {
        return this.system;
    }

    public void setSystem(String system) {
        this.system = system;
    }

    public String toString() {
        return "Country{name='" + this.name + "', system='" + this.system + "'}";
    }
}

Province

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package cn.itcast.pojo;

public class Province {
    private String name;
    private String direction;

    public Province() {
    }

    public Province(String name, String direction) {
        this.name = name;
        this.direction = direction;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDirection() {
        return this.direction;
    }

    public void setDirection(String direction) {
        this.direction = direction;
    }

    public String toString() {
        return "Province{name='" + this.name + "', direction='" + this.direction + "'}";
    }
}

CommonConfig

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package cn.itcast.config;

import cn.itcast.pojo.Country;
import cn.itcast.pojo.Province;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.context.annotation.Bean;

public class CommonConfig {
    public CommonConfig() {
    }

    @ConditionalOnProperty(
        prefix = "country",
        name = {"name", "system"}
    )
    @Bean
    public Country country(@Value("${country.name}") String name, @Value("${country.system}") String system) {
        return new Country(name, system);
    }

    @Bean
    public Province province() {
        return new Province();
    }
}

CommonAutoConfig

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package cn.itcast.config;

import org.springframework.boot.autoconfigure.AutoConfiguration;
import org.springframework.context.annotation.Import;

@AutoConfiguration
@Import({CommonConfig.class})
public class CommonAutoConfig {
    public CommonAutoConfig() {
    }
}

xxx.imports

cn.itcast.config.CommonAutoConfig

以上封装好的jar包就能自动注入了

接着在工程中引用

package com.geji;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;

/**
 * Hello world!
 *
 */
@SpringBootApplication
public class SpringbootAutoConfigApplication
{
    public static void main( String[] args )
    {
        ApplicationContext context= SpringApplication.run(SpringbootAutoConfigApplication.class,args);
        System.out.println(context.getBean("dispatcherServlet"));
        System.out.println(context.getBean("province"));

    }
}

以上是自动配置功能项目中也能用了，但是在实际工作中会更进一步，编写starter用来实现依赖管理功能，这样的话给别人用的时候就更方便了

创建两个maven工程dmybatis-spring-boot-aotuconfigure，dmybatis-spring-boot-starter