SpringBoot--自动加载

1 单执行main方法后执行的事情如下：

在org.springframework.boot.autoconfigure.spring.factories中部分配置如下:

org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration,\

从上可知，Redis是自动配置的。

2 Redis配置修改
在RedisAutoConfiguration中：

@Configuration@ConditionalOnClass({ JedisConnection.class, RedisOperations.class, Jedis.class })//在项目中发现了JedisConnection.class, RedisOperations.class, Jedis.class会初始化redis配置。@EnableConfigurationProperties(RedisProperties.class)public class RedisAutoConfiguration {

通过查阅全局配置文档说明，可配置Redis服务器相关信息：

# REDIS (RedisProperties)spring.redis.cluster.max-redirects= # Maximum number of redirects to follow when executing commands across the cluster.spring.redis.cluster.nodes= # Comma-separated list of "host:port" pairs to bootstrap from.spring.redis.database=0 # Database index used by the connection factory.spring.redis.url= # Connection URL, will override host, port and password (user will be ignored), e.g. redis://user:[e-mail]:6379spring.redis.host=localhost # Redis server host.spring.redis.password= # Login password of the redis server.spring.redis.ssl=false # Enable SSL support.spring.redis.pool.max-active=8 # Max number of connections that can be allocated by the pool at a given time. Use a negative value for no limit.spring.redis.pool.max-idle=8 # Max number of "idle" connections in the pool. Use a negative value to indicate an unlimited number of idle connections.spring.redis.pool.max-wait=-1 # Maximum amount of time (in milliseconds) a connection allocation should block before throwing an exception when the pool is exhausted. Use a negative value to block indefinitely.spring.redis.pool.min-idle=0 # Target for the minimum number of idle connections to maintain in the pool. This setting only has an effect if it is positive.spring.redis.port=6379 # Redis server port.spring.redis.sentinel.master= # Name of Redis server.spring.redis.sentinel.nodes= # Comma-separated list of host:port pairs.spring.redis.timeout=0 # Connection timeout in milliseconds.

在src/main/respurces下创建的application.properties文件，

spring.redis.url= 127.0.0.1

当执行SpringApplication初始化时，会自动初始化Redis相关的信息。

@ConfigurationProperties(prefix = "spring.redis")public class RedisProperties {    /**     * Database index used by the connection factory.     */    private int database = 0;    /**     * Redis url, which will overrule host, port and password if set.     */    private String url;    /**     * Redis server host.     */    private String host = "localhost";

如上，将会在application.properties中找spring.redis前缀的配置信息，例如spring.redis.url的值映射到String url中。
部分摘自某智播客。

3 创建一个自定义加载的模块，类似于启动的时候自动加载spring.factory中的内容。
application.properties:

hello.msg=hello

配置文件映射对应的类：

@ConfigurationProperties(prefix="hello")public class HelloProperties {    private final String MSG="WORLD";    private String msg=MSG;    public String getMsg() {        return msg;    }    public void setMsg(String msg) {        this.msg = msg;    }}

被自动创建的服务:

public class HelloService {     private String msg;    public String sayHello(){        return "hello"+this.msg;    }    public String getMsg() {        return msg;    }    public void setMsg(String msg) {        this.msg = msg;    }}

自动创建中心：

@Configuration@EnableConfigurationProperties(HelloProperties.class)//开启声明注入，将配置文件中的值映射到变量中@ConditionalOnClass(HelloService.class)//判断HelloService在类路径中是否存在，@ConditionalOnProperty(prefix="hello",value="enabled",matchIfMissing=true)public class HelloServiceAutoConfiguration {    @Autowired    private HelloProperties helloProperties;    @Bean    @ConditionalOnMissingBean(HelloService.class)//没有的情况下自动创建    public HelloService helloService(){        HelloService helloService=new HelloService();        helloService.setMsg(helloProperties.getMsg());        return helloService;    }}

在src/main/resources/下创建META-INF文件夹后在META-INF装中创建spring.factories，

# Auto Configureorg.springframework.boot.autoconfigure.EnableAutoConfiguration=\com.text.springboot.autoconfigure.hello.HelloServiceAutoConfiguration

Maven clean一下项目后install，在另外一个项目中依赖。启动

<dependencies>        <dependency>            <groupId>text</groupId>            <artifactId>helloworld</artifactId>            <version>0.0.1-SNAPSHOT</version>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-autoconfigure</artifactId>            <version>1.5.2.RELEASE</version>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>            <version>1.5.2.RELEASE</version>        </dependency>    </dependencies>

打开debug模式：
application.properties

debug=true

启动：

@RestController@SpringBootApplicationpublic class TextApplication {    @Autowired    private HelloService helloService;    @RequestMapping("/")    public String index(){        return helloService.sayHello();    }    public static void main(String[] args) {        SpringApplication.run(TextApplication.class, args);    }}

执行结果：
在

Positive matches:

中查看到HelloService已自动加载。
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