Spring Boot 手写starter！！！

原因：为什么要手写starter？？？

        原因：简化功能。

实例：以分页为例：写一个starter。

1.首先定义一个PageX注解。

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface PageX {
}

2.对这个注解进行增强，PageXAop。

/*
 * Copyright (c) 2020, 2024,  All rights reserved.
 *
 */
package cn.scl.pagex.aop;
 
import cn.hutool.core.util.ObjectUtil;
import com.github.pagehelper.PageHelper;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
 
import javax.servlet.http.HttpServletRequest;
 
/**
 * 
Project: pages - PageXAOP
 * 
Powered by scl On 2024-02-18 16:32:09
 * 
描述：
 *
 * @author 孙臣龙 [1846080280@qq.com]
 * @version 1.0
 * @since 17
 */
@Component
@Aspect
public class PageXAOP {
 
    @Pointcut("@annotation(cn.scl.core.annotations.PageX)")
    public void pointcut(){}
 
    @Around("pointcut()")
    public Object around(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println("目标方法执行之前");
        //获取请求
        RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = ((ServletRequestAttributes) requestAttributes).getRequest();
        //获取参数
        String pageNum = request.getParameter("pageNum");
        String pageSize = request.getParameter("pageSize");
        if(ObjectUtil.isNotEmpty(pageNum) && ObjectUtil.isNotEmpty(pageSize) ){
            PageHelper.startPage(Integer.parseInt(pageNum),Integer.parseInt(pageSize));
        }
        Object result = pjp.proceed();//执行目标方法
        System.out.println("目标方法执行之后");
        return result;
    }
}

3、定义统一返回格式，ResponseDTO。

/*
 * Copyright (c) 2020, 2024,  All rights reserved.
 *
 */
package cn.scl.model.dto;
 
import lombok.Data;
 
/**
 * 
Project: pages - ResponseDTO
 * 
Powered by scl On 2024-02-18 16:26:38
 * 
描述：
 *
 * @author 孙臣龙 [1846080280@qq.com]
 * @version 1.0
 * @since 17
 */
@Data
public class ResponseDTO {
    private int code ; //0为请求成功，非0为请求失败
    private String message; //返回的信息
    private Object data; //返回的数据
 
    //请求成功调用方法
    public static ResponseDTO success(Object data){
        ResponseDTO responseDTO = new ResponseDTO();
        responseDTO.setCode(0);
        responseDTO.setData(data);
        return responseDTO;
    }
    //请求失败调用方法
    public static ResponseDTO error(int code,String message){
        ResponseDTO responseDTO = new ResponseDTO();
        responseDTO.setCode(code);
        responseDTO.setMessage(message);
        return responseDTO;
    }
}

4、统一对controller进行处理，MyResponseAdvice。

/*
 * Copyright (c) 2020, 2024,  All rights reserved.
 *
 */
package cn.scl.pagex.advice;
 
import cn.hutool.json.JSONUtil;
import cn.scl.core.exception.BizException;
import cn.scl.model.dto.ResponseDTO;
import com.github.pagehelper.Page;
import org.springframework.core.MethodParameter;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;
 
import java.util.HashMap;
import java.util.Map;
 
/**
 * 
Project: pages - MyResponseAdvice
 * 
Powered by scl On 2024-02-18 16:48:23
 * 
描述：
 *
 * @author 孙臣龙 [1846080280@qq.com]
 * @version 1.0
 * @since 17
 */
@RestControllerAdvice
public class MyResponseAdvice implements ResponseBodyAdvice