Spring-Boot-Starter

自定义Starter

案例一：读取application.yml中的参数

1、创建

1、创建maven工程hello-spring-boot-starter

2、pom中添加依赖

<?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>org.example</groupId>
    <artifactId>hello-spring-boot-starter</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.2.RELEASE</version>
        <relativePath/>
    </parent>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
        </dependency>
    </dependencies>
</project>

3、创建HelloProperties
配置属性类，用于封装配置文件中配置的参数信息

package org.example.config;

import org.springframework.boot.context.properties.ConfigurationProperties;

/**
 * TODO 配置属性类，用于封装配置文件中配置的参数信息
 *
 * @author ss_419
 * @version 1.0
 * @date 2023/7/8 13:55
 */
@ConfigurationProperties(prefix = "hello")
public class HelloProperties {
    private String name;
    private String address;

    public String getName() {
        return name;
    }

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

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "HelloProperties{" +
                "name='" + name + '\'' +
                ", address='" + address + '\'' +
                '}';
    }
}

4、创建HelloService
这个类用于对读取到的参数进行一些业务上的操作

package org.example.service;

/**
 * TODO
 *
 * @author ss_419
 * @version 1.0
 * @date 2023/7/8 14:03
 */
public class HelloService {
    private String name;
    private String address;

    public HelloService(String name, String address) {
        this.name = name;
        this.address = address;
    }

    public String sayHello(){
        return "你好！我的名字叫做"+name+"，地址是" + address;
    }
}

5、创建HelloServiceAutoConfiguration（用于自动配置HelloService对象）

package org.example.config;

import org.example.service.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * TODO 自动配置类
 * 通过@Configuration + @Bean 实现自动创建对象
 *
 * @author ss_419
 * @version 1.0
 * @date 2023/7/8 14:06
 */
@Configuration
// 一定要加上这个注解，否则Spring找不到这个配置类
@EnableConfigurationProperties(value = HelloProperties.class)
public class HelloServiceAutoConfiguration {


    private HelloProperties helloProperties;

    // 通过构造方法注入配置属性对象HelloProperties
    public HelloServiceAutoConfiguration(HelloProperties helloProperties) {
        this.helloProperties = helloProperties;
    }
    // 实例化HelloService并载入Spring IOC 容器
    @Bean
    @ConditionalOnMissingBean// Spring中没有这个实例的时候再去创建
    public HelloService helloService(){
        return new HelloService(helloProperties.getName(), helloProperties.getAddress());
    }
}

6、在resources目录下创建META-INF/spring.factories

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.example.config.HelloServiceAutoConfiguration

7、将工程打包到maven仓库中

2、使用

1、创建项目，导入自定义starter

2、创建application.yml配置文件

3、创建启动类

package org.example;

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

/**
 * TODO
 *
 * @author ss_419
 * @version 1.0
 * @date 2023/7/8 14:39
 */
@SpringBootApplication
public class HelloApplication {
    public static void main(String[] args) {
        SpringApplication.run(HelloApplication.class,args);
    }
}

4、创建测试Controller

package org.example.controller;

import org.example.annotaion.MyLog;
import org.example.service.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * TODO
 *
 * @author ss_419
 * @version 1.0
 * @date 2023/7/8 14:36
 */
@RestController
@RequestMapping("/hello")
public class HelloController {

    @Autowired
    private HelloService helloService;

    @GetMapping("/sayHello")
    
    public String sayHello() {
     return helloService.sayHello();
    }
}

5、测试

案例二：通过自动配置来创建一个拦截器对象，通过此拦截器对象来实现记录日志功能

1、创建

1、创建maven项目并且引入依赖

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.2.RELEASE</version>
        <relativePath/>
    </parent>
    <groupId>org.example</groupId>
    <artifactId>log-spring-boot-starter</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>
</project>

2、创建MyLog注解

package org.example.annotaion;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface MyLog {
    /**
     * 方法描述
     * @return
     */
    String desc() default "";
}

3、创建日志拦截器

package org.example.interceptor;

import org.example.annotaion.MyLog;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;

/**
 * TODO 自定义日志拦截器
 *
 * @author ss_419
 * @version 1.0
 * @date 2023/7/8 17:43
 */
public class MyLogInterceptor extends HandlerInterceptorAdapter {
    private static final ThreadLocal<Long> startTimeThreadLocal = new ThreadLocal<>();// 记录时间毫秒值

    /**
     * 执行之前
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 进行转换
        HandlerMethod handlerMethod = (HandlerMethod) handler;
        Method method = handlerMethod.getMethod();
        // 获取方法上的注解MyLog
        MyLog annotation = method.getAnnotation(MyLog.class);
        if(annotation != null){
            // 说明当前拦截到的方法上加入了MyLog注解
            long currentTimeMillis = System.currentTimeMillis();
            startTimeThreadLocal.set(currentTimeMillis);
        }
        return true;
    }

    /**
     * 执行之后
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        HandlerMethod handlerMethod = (HandlerMethod) handler;
        Method method = handlerMethod.getMethod();

        // 获取方法上的注解MyLog
        MyLog annotation = method.getAnnotation(MyLog.class);
        if(annotation != null){
            // 说明当前拦截到的方法上加入了MyLog注解
            Long startTime = startTimeThreadLocal.get();
            long endTime = System.currentTimeMillis();
            long optTime =  endTime - startTime;

            String requestUri = request.getRequestURI();
            String methodName = method.getDeclaringClass().getName() + "."+
                                method.getName()+"()";
            String methodDesc = annotation.desc();

            System.out.println("请求uri："+requestUri);
            System.out.println("请求方法名："+methodName);
            System.out.println("方法描述："+methodDesc);
            System.out.println("方法执行时间："+optTime+"ms");

        }
        super.postHandle(request, response, handler, modelAndView);
    }
}

4、创建自动装配对象

package org.example.config;

import org.example.interceptor.MyLogInterceptor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * TODO
 *
 * @author ss_419
 * @version 1.0
 * @date 2023/7/8 18:08
 */
@Configuration
public class MyLogAutoConfiguration implements WebMvcConfigurer {
    /**
     * 注册自定义日志拦截器
     * @param registry
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new MyLogInterceptor());
    }
}

5、在resources下创建META-INF，在该文件夹下创建spring.factories
该配置文件用于扫描自动装配类

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.example.config.MyLogAutoConfiguration  

2、使用

1、创建一个web项目，并且引入依赖，pom.xml如下：

<?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>org.example</groupId>
    <artifactId>use-my-spring-boot-starter-demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.2.RELEASE</version>
        <relativePath/>
    </parent>
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.example</groupId>
            <artifactId>log-spring-boot-starter</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.example</groupId>
            <artifactId>hello-spring-boot-starter</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>

</project>

2、创建测试Controller
在测试的方法上添加上自定义的MyLog注解，当该方法执行的时候就会在控制台输出对应信息

package org.example.controller;

import org.example.annotaion.MyLog;
import org.example.service.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * TODO
 *
 * @author ss_419
 * @version 1.0
 * @date 2023/7/8 14:36
 */
@RestController
@RequestMapping("/hello")
public class HelloController {

    @Autowired
    private HelloService helloService;

    @GetMapping("/sayHello")
    @MyLog(desc = "sayHello方法")
    public String sayHello() {
     return helloService.sayHello();
    }
}

3、测试

到这里，对于自定义starter的案例就结束了。

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