1.1. 01-SpringBoot高级-今日内容

  • SpringBoot自定配置
    • SpringBoot事件监听
    • SpringBoot流程分析
    • SpringBoot监控
    • SpringBoot部署

1.2. 02-SpringBoot自动配置-Condition-1

Condition是Spring4.0后引入的条件化配置接口,通过实现Condition接口可以完成有条件的加载相应的Bean

@Conditional要配和Condition的实现类(ClassCondition)进行使用

  • ClassCondition

public class ClassCondition implements Condition {
    /**
     *
     * @param context 上下文对象。用于获取环境,IOC容器,ClassLoader对象
     * @param metadata 注解元对象。 可以用于获取注解定义的属性值
     * @return
     */
    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {

        //1.需求: 导入Jedis坐标后创建Bean
        //思路:判断redis.clients.jedis.Jedis.class文件是否存在
        boolean flag = true;
        try {
            Class<?> cls = Class.forName(redis.clients.jedis.Jedis);
        } catch (ClassNotFoundException e) {
            flag = false;
        }
        return flag;

    }
}
  • UserConfig
@Configuration
public class UserConfig {

    @Bean
    @Conditional(ClassCondition.class)
    public User user(){
        return new User();
    }

}

测试

@SpringBootApplication
public class SpringbootConditionApplication {

    public static void main(String[] args) {
        //启动SpringBoot的应用,返回Spring的IOC容器
        ConfigurableApplicationContext context = SpringApplication.run(SpringbootConditionApplication.class, args);

        Object user = context.getBean(“user”);
        System.out.println(user);

    }

}

1.3. 03-SpringBoot自动配置-Condition-2

需求:将类的判断定义为动态的。判断哪个字节码文件存在可以动态指定。

自定义条件注解类

import org.springframework.context.annotation.Conditional;

import java.lang.annotation.*;


@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Conditional(ClassCondition.class)
public @interface ConditionOnClass {
    String[] value();
}

注意:此处@ConditionOnClass为自定义注解

@Configuration
public class UserConfig {

    @Bean
    //@Conditional(ClassCondition.class)
    @ConditionOnClass(“com.alibaba.fastjson.JSON)
    public User user(){
        return new User();
    }

    @Bean
    @ConditionalOnProperty(name = “itcast”,havingValue = “itheima”)
    public User user2(){
        return new User();
    }

}

测试User对象的创建

@SpringBootApplication
public class SpringbootConditionApplication {

    public static void main(String[] args) {
        //启动SpringBoot的应用,返回Spring的IOC容器
        ConfigurableApplicationContext context = SpringApplication.run(SpringbootConditionApplication.class, args);

        Object user = context.getBean(“user”);
        System.out.println(user);

    }

}

查看条件注解源码

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SpringBoot 提供的常用条件注解:

ConditionalOnProperty:判断配置文件中是否有对应属性和值才初始化Bean

ConditionalOnClass:判断环境中是否有对应字节码文件才初始化Bean

ConditionalOnMissingBean:判断环境中没有对应Bean才初始化Bean

1.4. 04-SpringBoot自动配置-切换内置web服务器

查看继承关系图

1571306414687

排除Tomcat

1571306366201

pom文件中的排除依赖效果

 <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <!—排除tomcat依赖—>
            <exclusions>
                <exclusion>
                    <artifactId>spring-boot-starter-tomcat</artifactId>
                    <groupId>org.springframework.boot</groupId>
                </exclusion>
            </exclusions>
        </dependency>

        <!—引入jetty的依赖—>
        <dependency>
            <artifactId>spring-boot-starter-jetty</artifactId>
            <groupId>org.springframework.boot</groupId>
        </dependency>

1.5. 05-SpringBoot自动配置-Enable注解原理

  • SpringBoot不能直接获取在其他工程中定义的Bean

    演示代码:

    springboot-enable工程

    /**
     * @ComponentScan 扫描范围:当前引导类所在包及其子包
    *
     * com.itheima.springbootenable
     * com.itheima.config
     * //1.使用@ComponentScan扫描com.itheima.config包
     * //2.可以使用@Import注解,加载类。这些类都会被Spring创建,并放入IOC容器
     * //3.可以对Import注解进行封装。
     */
    
    //@ComponentScan(“com.itheima.config”)
    //@Import(UserConfig.class)
    @EnableUser
    @SpringBootApplication
    public class SpringbootEnableApplication {
    
        public static void main(String[] args) {
            ConfigurableApplicationContext context = SpringApplication.run(SpringbootEnableApplication.class, args);
    
         //获取Bean
            Object user = context.getBean(“user”);
            System.out.println(user);
    
        }
    
    }
    

    pom中引入springboot-enable-other

           <dependency>
                <groupId>com.itheima</groupId>
              <artifactId>springboot-enable-other</artifactId>
                <version>0.0.1-SNAPSHOT</version>
          </dependency>
    

    springboot-enable-other工程

    UserConfig

    ```java @Configuration public class UserConfig {

    @Bean
    

    public User user() {

        return new User();
    

    }

}


  **EnableUser注解类**

  ```java
  import org.springframework.context.annotation.Import;

  import java.lang.annotation.*;

  @Target(ElementType.TYPE)
  @Retention(RetentionPolicy.RUNTIME)
@Documented
  @Import(UserConfig.class)
public @interface EnableUser {

}

原因:@ComponentScan 扫描范围:当前引导类所在包及其子包

三种解决方案:

1.使用@ComponentScan扫描com.itheima.config包

2.可以使用@Import注解,加载类。这些类都会被Spring创建,并放入IOC容器

3.可以对Import注解进行封装。

重点:Enable注解底层原理是使用@Import注解实现Bean的动态加载

1.6. 06-SpringBoot自动配置-@Import详解

@Enable*底层依赖于@Import注解导入一些类,使用@Import导入的类会被Spring加载到IOC容器中。而@Import提供4中用法:

①导入Bean

②导入配置类

③导入 ImportSelector 实现类。一般用于加载配置文件中的类

④导入 ImportBeanDefinitionRegistrar 实现类。

  • 导入Bean @Import(User.class)

  • 导入配置类 @Import(UserConfig.class)

  • 导入 ImportSelector 实现类 @Import(MyImportSelector.class)

    MyImportSelector

    public class MyImportSelector implements ImportSelector {
        @Override
        public String[] selectImports(AnnotationMetadata importingClassMetadata) {
            return new String[]{com.itheima.domain.User,com.itheima.domain.Role};
        }
    }
    
  • 导入 ImportBeanDefinitionRegistrar 实现类。@Import({MyImportBeanDefinitionRegistrar.class})

    ```java public class MyImportBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar {

    @Override
    public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
        AbstractBeanDefinition beanDefinition = BeanDefinitionBuilder.rootBeanDefinition(User.class).getBeanDefinition();
        registry.registerBeanDefinition(“user”, beanDefinition);
    
  }

}


  SpringbootEnableApplication测试代码

  ```java

  /**
 * Import4中用法:
   *  1. 导入Bean
   *  2. 导入配置类
   *  3. 导入ImportSelector的实现类。
   *  4. 导入ImportBeanDefinitionRegistrar实现类
   */

  //@Import(User.class)
  //@Import(UserConfig.class)
  //@Import(MyImportSelector.class)
  //@Import({MyImportBeanDefinitionRegistrar.class})

  @SpringBootApplication
  public class SpringbootEnableApplication {

      public static void main(String[] args) {
          ConfigurableApplicationContext context = SpringApplication.run(SpringbootEnableApplication.class, args);

          /*//获取Bean
          Object user = context.getBean(“user”);
          System.out.println(user);*/

          /*User user = context.getBean(User.class);
          System.out.println(user);

          Role role = context.getBean(Role.class);
          System.out.println(role);*/

        /*  Object user = context.getBean(“user”);
          System.out.println(user);*/
       Map<String, User> map = context.getBeansOfType(User.class);
          System.out.println(map);

      }

  }

@EnableAutoConfiguration中使用的是第三种方式:@Import(AutoConfigurationImportSelector.class)

1.7. 07-SpringBoot自动配置-@EnableAutoConfiguration详解

1571387384701

  • @EnableAutoConfiguration 注解内部使用 @Import(AutoConfigurationImportSelector.class)来加载配置类。

  • 配置文件位置:META-INF/spring.factories,该配置文件中定义了大量的配置类,当 SpringBoot 应用启动时,会自动加载这些配置类,初始化Bean

  • 并不是所有的Bean都会被初始化,在配置类中使用Condition来加载满足条件的Bean

1.8. 08-SpringBoot自动配置-自定义starter步骤分析

需求:自定义redis-starter。要求当导入redis坐标时,SpringBoot自动创建Jedis的Bean。

步骤:

①创建 redis-spring-boot-autoconfigure 模块

②创建 redis-spring-boot-starter 模块,依赖 redis-spring-boot-autoconfigure的模块

③在 redis-spring-boot-autoconfigure 模块中初始化 Jedis 的 Bean。并定义META-INF/spring.factories 文件

④在测试模块中引入自定义的 redis-starter 依赖,测试获取 Jedis 的Bean,操作 redis。

1.9. 09-SpringBoot自动配置-自定义starter实现-1

  1. 创建redis-spring-boot-starter工程

​ pom文件中引入redis-spring-boot-autoconfigure

 <!—引入configure—>
        <dependency>
            <groupId>com.itheima</groupId>
            <artifactId>redis-spring-boot-autoconfigure</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>
  1. 创建redis-spring-boot-autoconfigure配置工程

创建RedisProperties配置文件参数绑定类

@ConfigurationProperties(prefix = “redis”)
public class RedisProperties {

    private String host = “localhost”;
    private int port = 6379;


    public String getHost() {
        return host;
    }

    public void setHost(String host) {
        this.host = host;
    }

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }
}

创建RedisAutoConfiguration自动配置类

@Configuration
@EnableConfigurationProperties(RedisProperties.class)
public class RedisAutoConfiguration {


    /**
     * 提供Jedis的bean
     */
    @Bean
    public Jedis jedis(RedisProperties redisProperties) {

        return new Jedis(redisProperties.getHost(), redisProperties.getPort());
    }
}

在resource目录下创建META-INF文件夹并创建spring.factories

注意:”\ “是换行使用的

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
  com.itheima.redis.config.RedisAutoConfiguration
  1. 在springboot-enable工程中引入自定义的redis的starter
  <!—自定义的redis的starter—>
        <dependency>
            <groupId>com.itheima</groupId>
            <artifactId>redis-spring-boot-starter</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

在SpringbootEnableApplication启动类中测试

 Jedis jedis = context.getBean(Jedis.class);
        System.out.println(jedis);

1.10. 10-SpringBoot自动配置-自定义starter实现-2

测试springboot-enable工程中的application.properties中的配置参数

redis.port=6666

使用注解完成有条件加载配置类

@Configuration
@EnableConfigurationProperties(RedisProperties.class)
@ConditionalOnClass(Jedis.class)
public class RedisAutoConfiguration {


    /**
     * 提供Jedis的bean
     */
    @Bean
    @ConditionalOnMissingBean(name = “jedis”)
    public Jedis jedis(RedisProperties redisProperties) {
        System.out.println(RedisAutoConfiguration....);
        return new Jedis(redisProperties.getHost(), redisProperties.getPort());
    }
}

1.11. 11-SpringBoot事件监听

Java中的事件监听机制定义了以下几个角色:

①事件:Event,继承 java.util.EventObject 类的对象

②事件源:Source ,任意对象Object

③监听器:Listener,实现 java.util.EventListener 接口 的对象

SpringBoot 在项目启动时,会对几个监听器进行回调,我们可以实现这些监听器接口,在项目启动时完成一些操作。

  • ApplicationContextInitializer、

  • SpringApplicationRunListener、

  • CommandLineRunner、

  • ApplicationRunner

自定义监听器的启动时机:MyApplicationRunner和MyCommandLineRunner都是当项目启动后执行,使用@Component放入容器即可使用

MyApplicationRunner

/**
 * 当项目启动后执行run方法。
 */
@Component
public class MyApplicationRunner implements ApplicationRunner {
    @Override
    public void run(ApplicationArguments args) throws Exception {
        System.out.println(ApplicationRunner...run”);
        System.out.println(Arrays.asList(args.getSourceArgs()));
    }
}

MyCommandLineRunner

@Component
public class MyCommandLineRunner implements CommandLineRunner {
    @Override
    public void run(String... args) throws Exception {
        System.out.println(CommandLineRunner...run”);
        System.out.println(Arrays.asList(args));
    }
}

MyApplicationContextInitializer的使用要在resource文件夹下添加META-INF/spring.factories

org.springframework.context.ApplicationContextInitializer=com.itheima.springbootlistener.listener.MyApplicationContextInitializer
@Component
public class MyApplicationContextInitializer implements ApplicationContextInitializer {
    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {
        System.out.println(“ApplicationContextInitializer....initialize”);
    }
}

MySpringApplicationRunListener的使用要添加构造器

public class MySpringApplicationRunListener implements SpringApplicationRunListener {

    public MySpringApplicationRunListener(SpringApplication application, String[] args) {
    }

    @Override
    public void starting() {
        System.out.println(“starting...项目启动中”);
    }

    @Override
    public void environmentPrepared(ConfigurableEnvironment environment) {
        System.out.println(“environmentPrepared...环境对象开始准备”);
    }

    @Override
    public void contextPrepared(ConfigurableApplicationContext context) {
        System.out.println(“contextPrepared...上下文对象开始准备”);
    }

    @Override
    public void contextLoaded(ConfigurableApplicationContext context) {
        System.out.println(“contextLoaded...上下文对象开始加载”);
    }

    @Override
    public void started(ConfigurableApplicationContext context) {
        System.out.println(“started...上下文对象加载完成”);
    }

    @Override
    public void running(ConfigurableApplicationContext context) {
        System.out.println(“running...项目启动完成,开始运行”);
    }

    @Override
    public void failed(ConfigurableApplicationContext context, Throwable exception) {
        System.out.println(“failed...项目启动失败”);
    }
}

1.12. 12-SpringBoot流程分析-初始化

  1. 配置启动引导类(判断是否有启动主类)

  2. 判断是否是Web环境

  3. 获取初始化类、监听器类

1571369439416

1.13. 13-SpringBoot流程分析-run

  1. 启动计时器

  2. 执行监听器

  3. 准备环境

  4. 打印banner:可以resource下粘贴自定义的banner

  5. 创建context

    refreshContext(context);
    

    执行refreshContext方法后才真正创建Bean

1571373793325

1.14. 14-SpringBoot监控-actuator基本使用

①导入依赖坐标

<dependency>

  <groupId>org.springframework.boot</groupId>

  <artifactId>spring-boot-starter-actuator</artifactId>

</dependency>

②访问http://localhost:8080/acruator

{
    “_links”:{
        “self”:{
            “href”:”http://localhost:8080/actuator”,
            “templated”:false
        },
        “health”:{
            “href”:”http://localhost:8080/actuator/health”,
            “templated”:false
        },
        “health-component-instance”:{
            “href”:”http://localhost:8080/actuator/health/{component}/{instance}”,
            “templated”:true
        },
        “health-component”:{
            “href”:”http://localhost:8080/actuator/health/{component}”,
            “templated”:true
        },
        “info”:{
            “href”:”http://localhost:8080/actuator/info”,
            “templated”:false
        }
    }
}

http://localhost:8080/actuator/info

在application.properties中配置

info.name=lucy
info.age=99

http://localhost:8080/actuator/health

开启健康检查详细信息

management.endpoint.health.show-details=always
{
    “status”:”UP”,
    “details”:{
        “diskSpace”:{
            “status”:”UP”,
            “details”:{
                “total”:159579508736,
                “free”:13558104064,
                “threshold”:10485760
            }
        },
        “redis”:{
            “status”:”UP”,
            “details”:{
                “version”:2.4.5}
        }
    }
}

1.15. 15-SpringBoot监控-actuator开启所有endpoint

开启所有endpoint

在application.properties中配置:

management.endpoints.web.exposure.include=*

开启所有endpoint的返回结果:

{
    “_links”:{
        “self”:{
            “href”:”http://localhost:8080/actuator”,
            “templated”:false
        },
        “auditevents”:{
            “href”:”http://localhost:8080/actuator/auditevents”,
            “templated”:false
        },
        “beans”:{
            “href”:”http://localhost:8080/actuator/beans”,
            “templated”:false
        },
        “caches-cache”:{
            “href”:”http://localhost:8080/actuator/caches/{cache}”,
            “templated”:true
        },
        “caches”:{
            “href”:”http://localhost:8080/actuator/caches”,
            “templated”:false
        },
        “health-component-instance”:{
            “href”:”http://localhost:8080/actuator/health/{component}/{instance}”,
            “templated”:true
        },
        “health”:{
            “href”:”http://localhost:8080/actuator/health”,
            “templated”:false
        },
        “health-component”:{
            “href”:”http://localhost:8080/actuator/health/{component}”,
            “templated”:true
        },
        “conditions”:{
            “href”:”http://localhost:8080/actuator/conditions”,
            “templated”:false
        },
        “configprops”:{
            “href”:”http://localhost:8080/actuator/configprops”,
            “templated”:false
        },
        “env”:{
            “href”:”http://localhost:8080/actuator/env”,
            “templated”:false
        },
        “env-toMatch”:{
            “href”:”http://localhost:8080/actuator/env/{toMatch}”,
            “templated”:true
        },
        “info”:{
            “href”:”http://localhost:8080/actuator/info”,
            “templated”:false
        },
        “loggers”:{
            “href”:”http://localhost:8080/actuator/loggers”,
            “templated”:false
        },
        “loggers-name”:{
            “href”:”http://localhost:8080/actuator/loggers/{name}”,
            “templated”:true
        },
        “heapdump”:{
            “href”:”http://localhost:8080/actuator/heapdump”,
            “templated”:false
        },
        “threaddump”:{
            “href”:”http://localhost:8080/actuator/threaddump”,
            “templated”:false
        },
        “metrics-requiredMetricName”:{
            “href”:”http://localhost:8080/actuator/metrics/{requiredMetricName}”,
            “templated”:true
        },
        “metrics”:{
            “href”:”http://localhost:8080/actuator/metrics”,
            “templated”:false
        },
        “scheduledtasks”:{
            “href”:”http://localhost:8080/actuator/scheduledtasks”,
            “templated”:false
        },
        “httptrace”:{
            “href”:”http://localhost:8080/actuator/httptrace”,
            “templated”:false
        },
        “mappings”:{
            “href”:”http://localhost:8080/actuator/mappings”,
            “templated”:false
        }
    }
}

1.16. 16-SpringBoot监控-springboot admin图形化界面使用

SpringBoot Admin 有两个角色,客户端(Client)和服务端(Server)。

以下为创建服务端和客户端工程步骤:

admin-server:

①创建 admin-server 模块

②导入依赖坐标 admin-starter-server

1571812312998

      <dependency>
            <groupId>de.codecentric</groupId>
            <artifactId>spring-boot-admin-starter-server</artifactId>
        </dependency>

③在引导类上启用监控功能@EnableAdminServer

@EnableAdminServer
@SpringBootApplication
public class SpringbootAdminServerApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootAdminServerApplication.class, args);
    }

}

admin-client:

①创建 admin-client 模块

②导入依赖坐标 admin-starter-client

          <dependency>
            <groupId>de.codecentric</groupId>
            <artifactId>spring-boot-admin-starter-client</artifactId>
        </dependency>

③配置相关信息:server地址等

# 执行admin.server地址
spring.boot.admin.client.url=http://localhost:9000

management.endpoint.health.show-details=always
management.endpoints.web.exposure.include=*

④启动server和client服务,访问server

1.17. 17-SpringBoot部署

SpringBoot 项目开发完毕后,支持两种方式部署到服务器:

①jar包(官方推荐)

②war包

更改pom文件中的打包方式为war

修改启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

@SpringBootApplication
public class SpringbootDeployApplication extends SpringBootServletInitializer {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootDeployApplication.class, args);
    }


    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
        return builder.sources(SpringbootDeployApplication.class);
    }
}

指定打包的名称

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