SpringBoot博客系统

1. 异常页配置

1.1 对于404和500错误

SpringBoot会自动拦截这两个异常，去resources–> templates --> error下找404.html和500.html

1.2 自定义异常页

需要自定义拦截器，根据自定义错误跳转到相应的错误页面
① 自定义拦截器，使用@ControllerAdvice + @ExceptionHandler 进行全局的 Controller 层异常处理

@ControllerAdvice 注解，用于拦截全局的Controller的异常，跳转到error页面

package com.javaer.blog.handler;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;

@ControllerAdvice
public class ControllerExceptionHandler {
    private Logger logger = LoggerFactory.getLogger(this.getClass());
    @ExceptionHandler(Exception.class)
    public ModelAndView exceptionHander(HttpServletRequest httpServletRequest, Exception e){
        logger.error("Request URL: {}, Exception: {}", httpServletRequest.getRequestURI(), e);
        ModelAndView mv = new ModelAndView();
        mv.addObject("url",httpServletRequest.getRequestURI());
        mv.addObject("exception",e);
        mv.setViewName("error/error");
        return mv;
    }
}

② 自定义NotFoundException异常，状态码标记为找不到

注意，在第一步拦截了所有的异常，我们需要对异常进行判断，不处理已经标明了状态码的异常，把标明了状态码的异常交个springBoot本身来处理

package com.javaer.blog.handler;
@ControllerAdvice
public class ControllerExceptionHandler {
    private Logger logger = LoggerFactory.getLogger(this.getClass());
    @ExceptionHandler(Exception.class)
    public ModelAndView exceptionHander(HttpServletRequest httpServletRequest, Exception e) throws Exception {
        logger.error("Request URL: {}, Exception: {}", httpServletRequest.getRequestURI(), e);

        if(AnnotationUtils.findAnnotation(e.getClass(), ResponseStatus.class)!=null){
            throw e;
        }
        ModelAndView mv = new ModelAndView();
        mv.addObject("url",httpServletRequest.getRequestURI());
        mv.addObject("exception",e);
        mv.setViewName("error/error");
        return mv;
    }
}

再自定义NotFoundException，状态码为找不到

package com.javaer.blog.Exception;

@ResponseStatus(HttpStatus.NOT_FOUND)
public class NotFoundException extends RuntimeException{
    public NotFoundException() {
    }

    public NotFoundException(String message) {
        super(message);
    }

    public NotFoundException(String message, Throwable cause) {
        super(message, cause);
    }
}

使用

package com.javaer.blog.web;
@Controller
public class indexController {
    @RequestMapping("/")
    public String index(){
        String blog = null;
        if(blog == null){
            throw new NotFoundException("博客不存在");
        }

        return "index";
    }
}

2. 日志处理

希望在日志记录
① 请求的url
② 访问者ip
③ 调用的方法
④ 参数
⑤ 返回内容

做法：
不用在每个controller里面进行内容记录，而是使用aop来针对切面的前后来处理

package com.javaer.blog.aspect;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;
import java.util.Arrays;

@Aspect
@Component
public class LogAspect {
    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    private class ReqeustLog {
        private String url;
        private String ip;
        private String classMethod;
        private Object[] args;

        public ReqeustLog(String url, String ip, String classMethod, Object[] args) {
            this.url = url;
            this.ip = ip;
            this.classMethod = classMethod;
            this.args = args;
        }

        @Override
        public String toString() {
            return "ReqeustLog{" + "url='" + url + '\'' + ", ip='" + ip + '\'' + ", classMethod='" + classMethod + '\'' + ", args=" + Arrays.toString(args) + '}';
        }
    }
    //定义一个切面，针对web下的所有类的所有方法
    @Pointcut("execution(* com.javaer.blog.web.*.*(..))")
    public void log(){

    }

    //切面之前
    @Before("log()")
    public void doBefore(JoinPoint joinPoint){
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        String classMethod = joinPoint.getSignature().getDeclaringTypeName() + "." + joinPoint.getSignature().getName();
        ReqeustLog reqeustLog = new ReqeustLog(request.getRequestURL().toString(), request.getRemoteAddr(), classMethod, joinPoint.getArgs());
        logger.info("Rquest  ----- {}", reqeustLog);
    }

    //切面之后
    @After("log()")
    public void doAfter(){

    }
    //返回之后
    @AfterReturning(returning = "result",pointcut = "log()")
    public void doAfterReturn(Object result){
        logger.info("Return ------ {}",result );
    }

}