JSR 303 以及 拦截器

前言

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一、JSR303

        JSR-303 是 JAVA EE 6 中的一项子规范，叫做 Bean Validation，官方参考实现是Hibernate Validator。

        

        简单的说，JSR-303就是用来做表单验证的。

我们之前用js、jQuery做表单验证，JS属于前端的脚本验证（只作用于客户端的浏览器中，可以被屏蔽）

JSR303属于服务端验证

        1、导入pom

      org.hibernate
      hibernate-validator
      6.0.7.Final
    

        2、Clazz

package com.zhw.model;

import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;

/**
 * @NotNull ：作用于基本数据类型
 * @NotEmpty    作用于集合
 * @NotBlank    作用于字符串
 */
public class Clazz {
    @NotNull(message = "班级编号不能为空")
    protected Integer cid;

    @NotBlank(message = "班级名不能为空")
    protected String cname;

    @NotBlank(message = "班级教员老师不能为空")
    protected String cteacher;

    protected String pic;

    public Clazz(Integer cid, String cname, String cteacher, String pic) {
        this.cid = cid;
        this.cname = cname;
        this.cteacher = cteacher;
        this.pic = pic;
    }

    public Clazz() {
        super();
    }

    public Integer getCid() {
        return cid;
    }

    public void setCid(Integer cid) {
        this.cid = cid;
    }

    public String getCname() {
        return cname;
    }

    public void setCname(String cname) {
        this.cname = cname;
    }

    public String getCteacher() {
        return cteacher;
    }

    public void setCteacher(String cteacher) {
        this.cteacher = cteacher;
    }

    public String getPic() {
        return pic;
    }

    public void setPic(String pic) {
        this.pic = pic;
    }
}

        3、ClazzController

package com.zhw.web;

import com.zhw.biz.ClazzBiz;
import com.zhw.model.Clazz;
import com.zhw.model.dto.ClazzDto;
import com.zhw.util.PageBean;
import org.apache.commons.io.FileUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.validation.FieldError;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author louis
 * @create  2022-08-17 18:39
 */
@Controller
@RequestMapping("/clz")
public class ClazzController {
    @Autowired
    private ClazzBiz clazzBiz;

    @RequestMapping("/list")
    public String list(HttpServletRequest req, Clazz clazz){
        PageBean pageBean = new PageBean();
        pageBean.setRequest(req);
        List lst = this.clazzBiz.listPager(clazz, pageBean);
        req.setAttribute("lst",lst);
        req.setAttribute("pageBean",pageBean);
        return "clzList";
    }

    @RequestMapping("/add")
    public String add(HttpServletRequest req, Clazz clazz){
        this.clazzBiz.insertSelective(clazz);
        return "redirect:/clz/list";
    }

    @RequestMapping("/edit")
    public String edit(HttpServletRequest req, Clazz clazz){
        this.clazzBiz.updateByPrimaryKeySelective(clazz);
        return "redirect:/clz/list";
    }

    @RequestMapping("/del")
    public String del(HttpServletRequest req, Clazz clazz){
        this.clazzBiz.deleteByPrimaryKey(clazz.getCid());
        return "redirect:/clz/list";
    }

    @RequestMapping("/toEdit")
    public String toEdit(HttpServletRequest req, Clazz clazz){
        if(clazz.getCid() != null){
            List lst = this.clazzBiz.listPager(clazz, null);
            req.setAttribute("b",lst.get(0));
        }
        return "clzEdit";
    }

    @RequestMapping("/upload")
    public String upload(HttpServletRequest request, ClazzDto clazzDto){
        try {
            String diskPath = "D:/Temp/images/";
            String reqPath = "/upload/mvc/";
            MultipartFile picFile = clazzDto.getPicFile();
//            完成文件上传
            FileUtils.copyInputStreamToFile(picFile.getInputStream(),new File(diskPath+picFile.getOriginalFilename()));
//            保存到数据库中
            Clazz clz = new Clazz();
            clz.setCid(clazzDto.getCid());
            clz.setPic(reqPath + picFile.getOriginalFilename());
            this.clazzBiz.updateByPrimaryKeySelective(clz);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "redirect:/clz/list";
    }

    //    给数据添加服务端校验
    @RequestMapping("/valiAdd")
    public String valiAdd(@Validated Clazz clazz, BindingResult result, HttpServletRequest req){
//        如果服务端验证不通过，有错误
        if(result.hasErrors()){
//            服务端验证了实体类的多个属性，多个属性都没有验证通过
            List fieldErrors = result.getFieldErrors();
            Map map = new HashMap<>();
            for (FieldError fieldError : fieldErrors) {
//                将多个属性的验证失败信息输送到控制台
                System.out.println(fieldError.getField() + ":" + fieldError.getDefaultMessage());
                map.put(fieldError.getField(),fieldError.getDefaultMessage());
            }
            req.setAttribute("errorMap",map);
        }else {
            this.clazzBiz.insertSelective(clazz);
            return "redirect:/clz/list";
        }
        return "clzEdit";
    }

    @RequestMapping("/download")
    public ResponseEntity download(Clazz clazz, HttpServletRequest req){

        try {
            //先根据文件id查询对应图片信息
            Clazz clz = this.clazzBiz.selectByPrimaryKey(clazz.getCid());
            String diskPath = "D:/Temp/images/";
            String reqPath = "/upload/mvc/";
            String realPath = clz.getPic().replace(reqPath,diskPath);
            String fileName = realPath.substring(realPath.lastIndexOf("/")+1);
            //下载关键代码
            File file=new File(realPath);
            HttpHeaders headers = new HttpHeaders();//http头信息
            String downloadFileName = new String(fileName.getBytes("UTF-8"),"iso-8859-1");//设置编码
            headers.setContentDispositionFormData("attachment", downloadFileName);
            headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
            //MediaType:互联网媒介类型  contentType：具体请求中的媒体类型信息
            return new ResponseEntity(FileUtils.readFileToByteArray(file),headers, HttpStatus.OK);
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }
}

         4、clzEidt.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
         pageEncoding="UTF-8"%>



    
    



    id:${errorMap.cid}

    cname:${errorMap.cname}

    cteacher:${errorMap.cteacher}

    

         效果展示

二、拦截器

        1、什么是拦截器

Spring MVC中的拦截器(Interceptor)类似于ServLet中的过滤器(Filter)，它主要用于拦截用户请求并作出相应的处理。例如通过拦截器可以进行权限验证、记录请求信息的日志、判断用户是否登录等。 

        2、拦截器的初识

                2.1、OneHandlerInterceptor

package com.zhw.intercept;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author louis
 * @create  2022-08-19 20:51
 */
public class OneHandlerInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
//        预处理
        System.out.println("[OneHandlerInterceptor] . preHandle");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
//       后处理
        System.out.println("[OneHandlerInterceptor] . postHandle...");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
//        完成后执行
        System.out.println("[OneHandlerInterceptor] . afterCompletion...");
    }
}

                2.2、HelloController

package com.zhw.web;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * @author louis
 * @create  2022-08-19 20:47
 */
@Controller
public class HelloController {
    @RequestMapping("/hello")
    public String hello(){
        System.out.println("come in ...");
        return "index";
    }
}

                2.3、springmvc-servlet的配置

          

        3、拦截器链

                3.1、TwoHandlerInterceptor

package com.zhw.intercept;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author louis
 * @create  2022-08-19 21:11
 */
public class TwoHandlerInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
//        预处理
        System.out.println("[TwoHandlerInterceptor] . preHandle");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
//       后处理
        System.out.println("[TwoHandlerInterceptor] . postHandle...");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
//        完成后执行
        System.out.println("[TwoHandlerInterceptor] . afterCompletion...");
    }
}

                3.2、springmvc-servlet的配置

三、案例

        1、login.jsp

<%--
  Created by IntelliJ IDEA.
  User: zhw
  Date: 2022/8/20
  Time: 21:28
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    


登录界面

        2、LoginController

package com.zhw.web;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;

/**
 * @author louis
 * @create  2022-08-20 21:29
 */
@Controller
public class LoginController {
    @RequestMapping("/login")
    public String login(HttpServletRequest request){
//        登录成功需要保存用户信息
        String uname = request.getParameter("uname");
        if("zhangsan".equals(uname)){
            request.getSession().setAttribute("uname",uname);
        }
        return "index";
    }

    @RequestMapping("/loginout")
    public String loginout(HttpServletRequest request){
        request.getSession().invalidate();
        return "index";
    }
}

http://localhost:8080/clz/list 不能访问，因为session被过滤掉
http://localhost:8080/login 不能访问，因为用户未成功登录被过滤掉
http://localhost:8080/login?uname=zs 可以访问
http://localhost:8080/loginout 清除掉session

 http://localhost:8080/clz/list

 http://localhost:8080/login

         

 http://localhost:8080/login?uname=zs

http://localhost:8080/loginout