• 【springboot】自定义starter(学习笔记)

    起步依赖

    自动配置

    条件依赖

    Bean参数获取

    Bean的发现

    bean的加载

    总结

    自定义starter案例一:hello-spring-boot-starter

    pom文件

    1. "1.0" encoding="UTF-8"?>
    2. <project xmlns="http://maven.apache.org/POM/4.0.0"
    3.          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    4.          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    5.     <modelVersion>4.0.0modelVersion>
    6.     <parent>
    7.         <artifactId>spring-boot-starter-parentartifactId>
    8.         <groupId>org.springframework.bootgroupId>
    9.         <version>2.7.2version>
    10.         <relativePath/>
    11.     parent>
    12.     <groupId>com.malguygroupId>
    13.     <artifactId>hello-spring-boot-starterartifactId>
    14.     <version>1.0-SNAPSHOTversion>
    15.     <properties>
    16.         <maven.compiler.source>8maven.compiler.source>
    17.         <maven.compiler.target>8maven.compiler.target>
    18.     properties>
    19.     <dependencies>
    20.         <dependency>
    21.             <groupId>org.springframework.bootgroupId>
    22.             <artifactId>spring-boot-starterartifactId>
    23.         dependency>
    24.         <dependency>
    25.             <groupId>org.springframework.bootgroupId>
    26.             <artifactId>spring-boot-autoconfigureartifactId>
    27.         dependency>
    28.     dependencies>
    29. project>

    配置属性类HelloProperties

    1. import org.springframework.boot.context.properties.ConfigurationProperties; 
    2. /**
    3. * 配置属性类,封装配置文件里的信息
    4. * 对应配置文件
    5. *   hello:
    6. *     name:
    7. *     address:
    8. */
    9. @ConfigurationProperties(prefix="hello") //参数的前缀;
    10. public class HelloProperties {
    11.     private String name;
    12.     private String address;
    13.     public String getName() {
    14.         return name;
    15.     }
    16.     public void setName(String name) {
    17.         this.name = name;
    18.     }
    19.     
    20.     public String getAddress() {
    21.         return address;
    22.     }
    23.     
    24.     public void setAddress(String address) {
    25.         this.address = address;
    26.     }
    27.     
    28.     @Override
    29.     public String toString() {
    30.         return "HelloProperties{" +
    31.             "name='" + name + '\'' +
    32.             ", address='" + address + '\'' +
    33.             '}';
    34.     }
    35. }

    服务类(到时boot会自动创建)HelloService

    1. public class HelloService {
    2.     private String name;
    3.     private String address;
    4.  
    5.     public HelloService(String name, String address) {
    6.         this.name = name;
    7.         this.address = address;
    8.     }
    9.     public String sayHello(){
    10.         return "你好,my name is "+name+",我 coming from "+address;
    11.     }
    12. }

    HelloServiceAutoConfiguration

    1. /**
    2.  * 自动配置类,自动配置hello对象
    3.  */
    4. @Configuration
    5. @EnableConfigurationProperties(value=HelloProperties.class)
    6. public class HelloServiceAutoConfiguration {
    7.     private HelloProperties helloProperties;
    8.     //通过构造方法注入配置对象
    9.     public HelloServiceAutoConfiguration(HelloProperties helloProperties) {
    10.         this.helloProperties = helloProperties;
    11.     }
    12.     @Bean
    13.     @ConditionalOnMissingBean //当没有这个bean的时候才创建
    14.     public HelloService helloService(){
    15.         return new HelloService(
    16.                 helloProperties.getName(),
    17.                 helloProperties.getAddress()
    18.         );
    19.     }
    20. }

    resources目录下创建META-INF/spring.factories , 可以加载自动配置类

    1. org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
    2. com.malguy.config.HelloServiceAutoConfiguration

    这样就可以install再使用了

    1. "1.0" encoding="UTF-8"?>
    2. <project mlns="http://maven.apache.org/POM/4.0.0"
    3.          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    4.          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    5.     <modelVersion>4.0.0modelVersion>
    6.     <parent>
    7.         <artifactId>spring-boot-starter-parentartifactId>
    8.         <groupId>org.springframework.bootgroupId>
    9.         <version>2.7.2version>
    10.     parent>
    11.     <groupId>org.examplegroupId>
    12.     <artifactId>myappartifactId>
    13.     <version>1.0-SNAPSHOTversion> 
    14.     <properties>
    15.         <maven.compiler.source>8maven.compiler.source>
    16.         <maven.compiler.target>8maven.compiler.target>
    17.     properties>
    18.     <dependencies>
    19.         
    20.         <dependency>
    21.             <groupId>com.malguygroupId>
    22.             <artifactId>hello-spring-boot-starterartifactId>
    23.             <version>1.0-SNAPSHOTversion>
    24.         dependency>
    25.         <dependency>
    26.             <groupId>org.springframework.bootgroupId>
    27.             <artifactId>spring-boot-starter-webartifactId>
    28.         dependency>
    29.     dependencies>
    30. project>
    1. server:
    2.   port:8080
    3. hello:
    4.   name: lihua
    5.   address: beijing
    1. @RestController
    2. @RequestMapping("/hello")
    3. public class HelloController {
    4.     @Autowired
    5.     private HelloService helloService;
    6.     @GetMapping("/say")
    7.     public String sayHello(){
    8.         return helloService.sayHello();
    9.     }
    10. }
    1. @SpringBootApplication
    2. public class HelloApplication {
    3.     public static void main(String[] args) {
    4.         SpringApplication.run(HelloApplication.class,args);
    5.     }
    6. }

    自定义starter案例二:案例一的基础上添加拦截器,实现记录日志功能

    依赖

    1. "1.0" encoding="UTF-8"?>
    2. <project xmlns="http://maven.apache.org/POM/4.0.0"
    3.          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    4.          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    5.     <modelVersion>4.0.0modelVersion>
    6.     <parent>
    7.         <artifactId>spring-boot-starter-parentartifactId>
    8.         <groupId>org.springframework.bootgroupId>
    9.         <version>2.7.2version>
    10.         <relativePath/>
    11.     parent>
    12.     <groupId>com.malguygroupId>
    13.     <artifactId>hello-spring-boot-starterartifactId>
    14.     <version>1.0-SNAPSHOTversion>
    15.     <properties>
    16.         <maven.compiler.source>8maven.compiler.source>
    17.         <maven.compiler.target>8maven.compiler.target>
    18.     properties>
    19.     <dependencies>
    20.         <dependency>
    21.             <groupId>org.springframework.bootgroupId>
    22.             <artifactId>spring-boot-starterartifactId>
    23.         dependency>
    24.         <dependency>
    25.             <groupId>org.springframework.bootgroupId>
    26.             <artifactId>spring-boot-autoconfigureartifactId>
    27.         dependency>
    28.         <dependency>
    29.             <groupId>org.springframework.bootgroupId>
    30.             <artifactId>spring-boot-starter-webartifactId>
    31.         dependency>
    32.         <dependency>
    33.             <groupId>org.springframework.bootgroupId>
    34.             <artifactId>spring-boot-configuration-processorartifactId>
    35.         dependency>
    36.     dependencies>
    37. project>

    自定义MyLog注解

    1. /**
    2.  * 自定义日志注解
    3.  */
    4. @Target(ElementType.METHOD)//只能加在方法上
    5. @Retention(RetentionPolicy.RUNTIME)//在运行时生效
    6. public @interface MyLog {
    7.     /**
    8.      * 方法描述
    9.      */
    10.     String desc() default "";
    11. }

    创建拦截器对象MyLogInterceptor

    1. /**
    2.  * 自定义日志拦截器
    3.  */
    4. public class MyLogInterceptor extends HandlerInterceptorAdapter {
    5.     private static final ThreadLocal startTimeThreadLocal=
    6.             new ThreadLocal<>(); //记录时间的毫秒值
    7.     //在controller方法执行前执行
    8.     @Override
    9.     public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    10.         HandlerMethod handlerMethod = (HandlerMethod) handler;
    11.         Method method = handlerMethod.getMethod();//获取当前拦截到的方法
    12.         MyLog myLog = method.getAnnotation(MyLog.class);//方法上获取mylog注解
    13.         if(myLog!=null){
    14.             //当前拦截的方法上加了MyLog注解
    15.             long startTime = System.currentTimeMillis();//获取当前时间(毫秒)
    16.             startTimeThreadLocal.set(startTime);
    17.         }
    18.         return true;
    19.     }
    20.     //在controller方法执行后执行
    21.     @Override
    22.     public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    23.         HandlerMethod handlerMethod = (HandlerMethod) handler;
    24.         Method method = handlerMethod.getMethod();//获取当前拦截到的方法
    25.         MyLog myLog = method.getAnnotation(MyLog.class);//方法上获取mylog注解
    26.         if(myLog!=null){
    27.             //当前拦截的方法上加了MyLog注解
    28.             Long startTime = startTimeThreadLocal.get();
    29.             long endTime = System.currentTimeMillis();//获取当前时间(毫秒)
    30.             long optTime=endTime-startTime;//计算controller方法执行时间
    31.             String requestUri= request.getRequestURI();
    32.             String methodName=method.getDeclaringClass().getName()+"."+
    33.                     method.getName();
    34.             String methodDesc=myLog.desc();
    35.             System.out.println("请求uri: "+requestUri);
    36.             System.out.println("请求方法名:　"+methodName);
    37.             System.out.println("方法描述: "+methodDesc);
    38.             System.out.println("方法执行时间: "+optTime+"ms");
    39.         }
    40.         super.postHandle(request, response, handler, modelAndView);
    41.     }
    42. }

    自动配置类自动实例化拦截器对象(注册为bean)

    1. @Configuration
    2. public class MyLogAutoConfiguration implements WebMvcConfigurer {
    3.     //注册自定义日志拦截器 
    4.     @Override
    5.     public void addInterceptors(InterceptorRegistry registry) {
    6.         registry.addInterceptor(new MyLogInterceptor());
    7.     }
    8. }

    spring.factories

    1. org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
    2. com.malguy.config.HelloServiceAutoConfiguration,\
    3. com.malguy.config.MyLogAutoConfiguration

    重新打包install,在myapp的controller方法上加注解,测试

    1. @RestController
    2. @RequestMapping("/hello")
    3. public class HelloController {
    4.     @Autowired
    5.     private HelloService helloService;
    6.     @GetMapping("/say")
    7.     @MyLog(desc="sayHello方法")
    8.     public String sayHello(){
    9.         return helloService.sayHello();
    10.     }
    11. }

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  • 原文地址：https://blog.csdn.net/m0_60707623/article/details/126654442