EE颠覆者5，6章boot基础和核心

妖狐艹你老母 2023-07-17 14:20 24阅读 0赞

运行项目：

mvn spring-boot:run

server:
      port: 9090
      contextPath: /helloboot

contextPath

context-path 这种方式是系统提示的

CONTEXT\_PATH

java -jar .\ch5_2_2-0.0.1-SNAPSHOT.jar --server.port=8888

book.name=spring boot

@Value("${book.name}")
    	 private String bookName;

## 类型安全的配置（基于 properties） ##

@ConfigurationProperties 将 配置文件关联

@Component
    @ConfigurationProperties(prefix = "author") //1 
    public class AuthorSettings { 
        private String name;
        private Long age;
        } //get set
    
    application.properties
    author.name=wyf
    author.age=32
        
        @Autowired
    	private AuthorSettings authorSettings; //1
        
        // 或者属性 ,locations = "classpath:config/author.properties"

## 日志配置 ##

Log4J log4J2 Logback，默认logback

logging.file=D:/mylog/log.log
    logging.level.org.springframework.web: DEBUG

## Profile配置 ##

application-\{profile\}.properties

application-prod.properties

application.properties 配置：
    spring.profiles.active=prod

application-dev.properties
    server.port=8888
    
    spring.profiles.active=prod
    server.port=80
    debug=true  //java -jar xx.jar --debug

## @SpringBootApplication ##

@Target(ElementType.TYPE)
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    @Inherited
    @Configuration
    @EnableAutoConfiguration
    @ComponentScan
    public @interface SpringBootApplication { }

# @EnableAutoConfiguration #

@Target(ElementType.TYPE)
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    @Inherited
    @Import({  EnableAutoConfigurationImportSelector.class,
    		AutoConfigurationPackages.Registrar.class })
    public @interface EnableAutoConfiguration { }

@Inherited 元注解是一个标记注解，@Inherited阐述了某个被标注的类型是被继承的。  
如果一个使用了@Inherited修饰的annotation类型被用于一个class，则这个annotation将被用于该class的子类。

@Order(Ordered.LOWEST_PRECEDENCE)
    注解@Order或者接口Ordered的作用是定义Spring IOC容器中Bean的执行顺序的优先级，
    而不是定义Bean的加载顺序，Bean的加载顺序不受@Order或Ordered接口的影响；

## http的编码配置 ##

spring.http.encoding.charset=UTF-8

# spring自动配置实战 #

HelloServiceAutoConfiguration
          - @ConditionalOnClass classes found: com.wisely.spring_boot_starter_hello.HelloService (OnClassCondition)
          - matched (OnPropertyCondition)
    
       HelloServiceAutoConfiguration#helloService
          - @ConditionalOnMissingBean (types: com.wisely.spring_boot_starter_hello.HelloService; SearchStrategy: all) found no beans (OnBeanCondition)

1.  spring-boot-start-hello
    
        <?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.wisely</groupId>
            <artifactId>spring-boot-starter-hello</artifactId>
            <version>0.0.1-SNAPSHOT</version>
            <packaging>jar</packaging>
        
            <name>spring-boot-starter-hello</name>
            <url>http://maven.apache.org</url>
        
            <properties>
                <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            </properties>
        
            <dependencies>
                <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-autoconfigure</artifactId>
                    <version>1.5.9.RELEASE</version>
                    
                </dependency>
        
        
                <dependency>
                    <groupId>junit</groupId>
                    <artifactId>junit</artifactId>
                    <version>3.8.1</version>
                    <scope>test</scope>
                </dependency>
            </dependencies>
        
        </project>
2.  属性配置：类型安全的属性获取
    
        @ConfigurationProperties(prefix = "hello") //读取配置
        public class HelloServiceProperties { 
            private static final String MSG="world";
            private String msg= MSG;//提供get set
        }

hello.msg= wangyunfei //如果不设置 默认为world

1.  判断依据类
    
        public class HelloService { 
            private String msg;
        
            public String sayHello(){ 
                return "Hello"+msg;
            }
        
        }
    
    > 根据此类 的存在与否 来创建 这个类的bean
2.  自动配置类
    
        @Configuration
        @EnableConfigurationProperties(HelloServiceProperties.class)//自动获取到配置
        @ConditionalOnClass(HelloService.class)//判断这个类在类路径中是否存在
        @ConditionalOnProperty(prefix = "hello",value = "enabled",matchIfMissing = true)
        public class HelloServiceAutoConfiguration { 
            @Autowired
            private HelloServiceProperties helloServiceProperties;
        
            @Bean
            @ConditionalOnMissingBean(HelloService.class)//如果容器中没有，自动创建一个bean
            public HelloService helloService(){ 
                HelloService helloService=new HelloService();
                helloService.setMsg(helloServiceProperties.getMsg());
                return helloService;
            }
        }
3.  配置文件，让自动配置生效
    
        src/main/resources/META-INF/spring.factories
        org.springframework.boot.autoconfigure.EnableAutoConfiguration=
        com.wisely.spring_boot_starter_hello.HelloServiceAutoConfiguration
    
    > 若有多个配置，用，隔开
4.  mvn install 并使用
    
        <dependency>
        			<groupId>com.wisely</groupId>
        			<artifactId>spring-boot-starter-hello</artifactId>
        			<version>0.0.1-SNAPSHOT</version>
        		</dependency>
        配置：
        hello.msg= wangyunfei
        debug=true
    
        @Autowired
        	HelloService helloService;
        	
        	@RequestMapping("/")
        	public String index(){ 
        		return helloService.sayHello();
        	}