• JSR303和拦截器

    目录

    一、JSR303

    1、pom依赖

    <dependency>
      <groupId>org.hibernategroupId>
      <artifactId>hibernate-validatorartifactId>
      <version>6.0.7.Finalversion>
    dependency>


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    2、后端

    ①实体类

    package com.xnx.ssm.model;

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

/**
 * NotNull:针对的是基本数据类型
 * NotEmpty:作用于集合
 * NotBlank:作用于字符串
 */
public class Clazz {
    @NotNull(message = "cid不能为空")
    protected Integer cid;

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

    @NotBlank(message = "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;
    }
}

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    ②ClazzController.java

    package com.xnx.ssm.web;

import com.xnx.ssm.biz.ClazzBiz;
import com.xnx.ssm.model.Clazz;
import com.xnx.ssm.model.dto.ClazzDto;
import com.xnx.ssm.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.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletRequest;
import javax.validation.Valid;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Controller
@RequestMapping("/clz")
public class ClazzController {
    @Autowired
    private ClazzBiz clazzBiz;
//    list->clzlist
//    toList->重定向list->"redirect:/clz/list"
//    toEdit->跳转到编辑界面->clzEdit
//    Clazz:以前是通过模型驱动接口封装，现在是直接在方法中接收参数即可

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

    @RequestMapping("/toEdit")
    public String toEdit(Clazz clazz, HttpServletRequest request){
        Integer cid = clazz.getCid();
//        传递的id代表了修改，没传代表新增
        if(cid != null){
            List<Clazz> lst = this.clazzBiz.listPager(clazz, null);
            request.setAttribute("b",lst.get(0));
        }
        return "clzEdit";
    }

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

    /**
     * @Valid 是与实体类中的服务端校验 注解配合使用的
     * BindingResult存放了所有违背校验的错误信息
     * @param clazz
     * @param bindingResult
     * @return
     */
    @RequestMapping("/valiAdd")
    public String valiAdd(@Valid Clazz clazz, BindingResult bindingResult,HttpServletRequest request){
        if(bindingResult.hasErrors()){
            Map msg=new HashMap();
//            违背规则
            List<FieldError> fieldErrors = bindingResult.getFieldErrors();
            for (FieldError fieldError : fieldErrors) {
//                cid : cid不能为空
                System.out.println(fieldError.getField() + ":" + fieldError.getDefaultMessage());
//                msg.put(cid,cid不能为空)
                msg.put(fieldError.getField(),fieldError.getDefaultMessage());

            }
            request.setAttribute("msg",msg);
//            如果出现了错误，一个将提示语显示在表单提交元素后方
            return "clzEdit";
        }else{
            this.clazzBiz.insertSelective(clazz);
        }
        return "redirect:/clz/list";
    }

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

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

//    文件上传
    @RequestMapping("/upload")
    public String upload(ClazzDto clazzDto){
        try{
//          前台上传的文件
            MultipartFile picFile = clazzDto.getPicFile();
//            InputStream inputStream = picFile.getInputStream();
            /*FileOutputStream fout = new FileOutputStream(new File("D/temp/1.png"));
            byte[] bbuf=new byte[1024];
            int len = 0;
            while(true){
                len=inputStream.read(bbuf,0,len);
                fout.write(bbuf,0,len);
                if(len<0){
                    break;
                }
            }*/
//            实际应该配置到resource.properties中
            String dispath="E:/temp/images";//图片的存放地址
//            http://localhost:8080/upload/mvc/**.png
            String requestPath="/upload/mvc";//数据库保存的地址，也是访问地址
//            拿到上传文件的名字
            String fileName = picFile.getOriginalFilename();//**.png

            FileUtils.copyInputStreamToFile(picFile.getInputStream(),new File(dispath+fileName));
//           将图片上传之后，并且将图片地址更新到数据库中
            Clazz clazz=new Clazz();
            clazz.setCid(clazzDto.getCid());
            clazz.setPic(requestPath+fileName);
            this.clazzBiz.updateByPrimaryKeySelective(clazz);
        }catch (Exception e){
            e.printStackTrace();
        }
        return "redirect:/clz/list";
    }

    //    文件下载
    @RequestMapping("/download")
    public ResponseEntity download(ClazzDto clazzDto){
        try{
//            1.点击下载传递文件的ID，通过文件的ID查询出文件的路径
            Clazz clazz = this.clazzBiz.selectByPrimaryKey(clazzDto.getCid());
            String pic=clazz.getPic();// /upload/mvc/**.png
//              实际应该配置到resource.properties中
            String diskPath="E:/temp/images/";//图片的存放地址
//            http://localhost:8080/upload/mvc/图片.png
            String requestPath="/upload/mvc/";//数据库保存的地址，也是访问地址
            
//            2.通过文件的请求地址，转换成文件存放的硬盘地
            String realPath=pic.replace(requestPath,diskPath);// E:/temp/images
            String fileName=realPath.substring(realPath.lastIndexOf("/")+1);
//            3.将硬盘中文件下载下来->固定代码
            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<byte[]>(FileUtils.readFileToByteArray(file),headers, HttpStatus.OK);
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }
}


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    3、前端

    clzEdit.jsp

    <%@ page language="java" contentType="text/html; charset=UTF-8"
         pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>编辑界面</title>
</head>
<body>
<%--
<form action="${pageContext.request.contextPath }/clz/${empty b ? 'add' : 'edit'}" method="post">
--%>
<form action="${pageContext.request.contextPath }/clz/${empty b ? 'valiAdd' : 'edit'}" method="post">
    cid:<input type="text" name="cid" value="${b.cid }"><span style="color: red">${msg.cid}</span><br>
    cname:<input type="text" name="cname" value="${b.cname }"><span style="color: red">${msg.cname}</span><br>
    cteacher:<input type="text" name="cteacher" value="${b.cteacher }"><span style="color: red">${msg.cteacher}</span><br>
    <input type="submit">
</form>
</body>
</html>

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    运行效果：
    在这里插入图片描述
    输入为空则提示

    二、拦截器

    1、拦截器的初步认识

    ①OneHandlerInterceptor

    package com.xnx.ssm.intercept;

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

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

/**
 * @author xnx
 * @create 2022-08-19 18:32
 */
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...");
    }
}


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    ②HelloController

    package com.xnx.ssm.web;

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

/**
 * @author xnx
 * @create 2022-08-19 19:21
 */
@Controller
public class HelloController {

    @RequestMapping("hello")
    public String hello(){
        System.out.println("进入业务方法...");
        return "index";
    }
}


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    ③springmvc-servlet的配置

    
    <mvc:interceptors>
        
        <bean class="com.xnx.ssm.intercept.OneHandlerInterceptor">bean>
    mvc:interceptors>

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    运行效果：
    在这里插入图片描述

    2、拦截器链

    在这里插入图片描述

    ①TwoHandlerInterceptor

    package com.xnx.ssm.intercept;

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

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

/**
 * @author xnx
 * @create 2022-08-19 18:32
 */
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...");
    }
}


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    ②springmvc-servlet的配置

    
    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/**"/>
            <bean class="com.xnx.ssm.intercept.OneHandlerInterceptor">bean>
        mvc:interceptor>
        <mvc:interceptor>
            <mvc:mapping path="/clz/**"/>
            <bean class="com.xnx.ssm.intercept.TwoHandlerInterceptor">bean>
        mvc:interceptor>
    mvc:interceptors>

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    运行效果：
    在这里插入图片描述
    在这里插入图片描述

    3、登录权限控制

    3.1 前端

    login.jsp

    <%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2022/8/19
  Time: 19:55
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
登录界面
</body>
</html>


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    3.2 后端

    LoginController

    package com.xnx.ssm.web;

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

import javax.servlet.http.HttpServletRequest;

/**
 * @author xnx
 * @create 2022-08-19 19:52
 */
@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";
    }

}


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    3.3运行效果

    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:
    在这里插入图片描述
    http://localhost:8080/login:
    在这里插入图片描述
    http://localhost:8080/login?uname=zs
    在这里插入图片描述
    http://localhost:8080/loginout
    在这里插入图片描述
    四种测试的控制台打印：
    在这里插入图片描述

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  • 原文地址：https://blog.csdn.net/weixin_67677668/article/details/126430797