暑期第四周总结

本周继续学习了springboot项目知识，开始写了一个简单的入门项目，瑞吉外卖
说一些核心技术和新接触的代码片段
使用了springMVC，持久层使用了mp技术大大简化开发，不仅省去了mapper层的编写，还省去了service层的编写，使用其中提供的基本业务方法即可，
核心代码：
过滤器

package open.reggie.filter;

import com.alibaba.fastjson.JSON;
import lombok.extern.slf4j.Slf4j;
import open.reggie.common.BaseContext;
import open.reggie.common.R;
import org.springframework.stereotype.Component;
import org.springframework.util.AntPathMatcher;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 检查用户是否已经登录
 */
@WebFilter(filterName = "loginCheckFilter",urlPatterns = "/*")
@Component
@Slf4j
public class LoginCheckFilter implements Filter {

    private static final AntPathMatcher PATH_MATCHER=new AntPathMatcher();
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest httpServletRequest=(HttpServletRequest) servletRequest;
        HttpServletResponse httpServletResponse=(HttpServletResponse) servletResponse;

        //1、获取请求的uri
        String requestURI = httpServletRequest.getRequestURI();

        log.info("拦截到请求：{}",requestURI);

        //定义不需要处理的请求
        String [] urls=new String[]{
                "/employee/login",
                "/employee/logout",
                "/backend/**",
                "/front/**"
        };
        //2、判断请求是否需要处理
        boolean check=check(urls,requestURI);


        //3、如果不需要处理，则直接返回
        if(check){
            log.info("本次{}请求不需要处理",requestURI);
            filterChain.doFilter(httpServletRequest,httpServletResponse);
            return;
        }
        //4、判断登录状态，如果已经登录，放行
        if(httpServletRequest.getSession().getAttribute("employee")!=null){
            log.info("用户已经登录");
            long id = Thread.currentThread().getId();
            log.info("当前线程的id是{}",id);

            Long empId = (Long) httpServletRequest.getSession().getAttribute("employee");
            BaseContext.setCurrentId(empId);

            filterChain.doFilter(httpServletRequest,httpServletResponse);
            return;
        }
        log.info("用户未登录");
        //5、如果未登录则返回未登录结果，通过输出流方式向客户端页面响应数据
        httpServletResponse.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
        return;
    }
    /**
     * 路径匹配，检查本次请求是否需要放行
     * @param urls
     * @param requestURI
     * @return
     */
    public boolean check(String[] urls,String requestURI){
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url, requestURI);
            if(match){
                return true;
            }
        }
        return false;
    }
}

全局异常处理器

package open.reggie.common;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.RestControllerAdvice;

import java.sql.SQLIntegrityConstraintViolationException;
/**
 * 全局异常处理类，带有RestController，Controller的注解的类中如果发生异常的话，会进入该类中，进行处理
 */
@RestControllerAdvice(annotations = {RestController.class, Controller.class})
@Slf4j
public class GlobalExceptionHandler {
    /**
     * 异常处理方法，注解的参数是表示出现这个异常会执行这个方法
     * @param e 异常类
     * @return 结果对象
     */
    @ExceptionHandler(SQLIntegrityConstraintViolationException.class)
    public R<String> exceptionHandler(SQLIntegrityConstraintViolationException e){
        log.error(e.getMessage());
        if(e.getMessage().contains("Duplicate entry")){
            return R.error("添加实体已存在");
        }
        return R.error("失败了");
    }
}

公共字段处理类

package open.reggie.common;

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import lombok.extern.slf4j.Slf4j;
import org.apache.ibatis.reflection.MetaObject;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;

@Component
@Slf4j
public class MyMetaObjectHandler implements MetaObjectHandler {
    /**
     * 插入操作自行填充
     * @param metaObject
     */
    @Override
    public void insertFill(MetaObject metaObject) {
        log.info("数据插入操作,公共字段填充");
        metaObject.setValue("createTime", LocalDateTime.now());
        metaObject.setValue("updateTime",LocalDateTime.now());

        metaObject.setValue("createUser",BaseContext.getCurrentId());
        metaObject.setValue("updateUser",BaseContext.getCurrentId());
    }

    /**
     * 更新操作自行填充
     * @param metaObject
     */
    @Override
    public void updateFill(MetaObject metaObject) {
        log.info("数组更新操作，公共字段填充");
        metaObject.setValue("updateTime",LocalDateTime.now());
        metaObject.setValue("updateUser",BaseContext.getCurrentId());
        long id = Thread.currentThread().getId();
        log.info("当前线程的id是{}",id);
    }
}

mp配置分页对象

package open.reggie.config;

import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * mybatis-plus分页插件配置
 */
@Configuration
public class MybatisPlusConfig {

    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor(){
        MybatisPlusInterceptor mybatisPlusInterceptor=new MybatisPlusInterceptor();
        mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor());
        return mybatisPlusInterceptor;
    }

}

网络层配置资源映射

package open.reggie.config;

import lombok.extern.slf4j.Slf4j;
import open.reggie.common.JacksonObjectMapper;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;

import java.util.List;

@Configuration
@Slf4j
public class WebMvcConfig extends WebMvcConfigurationSupport {
    /**
     * 设置静态资源映射
     * @param registry
     */
    @Override
    protected void addResourceHandlers(ResourceHandlerRegistry registry) {
        log.info("开始进行静态资源映射");
        registry.addResourceHandler("/backend/**").addResourceLocations("classpath:/backend/");
        registry.addResourceHandler("/front/**").addResourceLocations("classpath:/front/");
    }

    /**
     * 扩展MVC的消息转换器
     * @param converters
     */
    @Override
    protected void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
        MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter=new MappingJackson2HttpMessageConverter();
        mappingJackson2HttpMessageConverter.setObjectMapper(new JacksonObjectMapper());
        converters.add(0,mappingJackson2HttpMessageConverter);
    }
}