SpringMVC实战crud增删改查

一.公共页面的跳转

1.编写页面跳转控制类

package com.YU.web;

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

/**
 * @author YU
 * @create 2023-09-07 14:41
 */
@Controller
public class PageController {

    @RequestMapping("/page/{page}")
    public String toPage(@PathVariable("page") String page){
        return page;
    }

    @RequestMapping("/page/{dir}{page}")
    public String toDirPage(
            @PathVariable("dir") String dir,
            @PathVariable("page") String page){
        return dir + "/" + page;
    }
}

二.后端实现crud

1.利用mybatis插件生成实体模型和mapper接口和xml文件

在生成后的HBookMapper接口中，需要加上@Repository给Spring进行托管

2.编写切面类和工具类

2.1切面类：

package com.YU.aspect;

import com.YU.utils.PageBean;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;

import java.util.List;

/**
 * @author YU
 * @create 2023-08-25 17:17
 */
@Aspect //代表当前类为切面类
@Component //代表当前类交给Spring进行管理
public class PagerAspect {
    @Around("execution(* *..*biz.*Pager(..))")
    public Object invoke(ProceedingJoinPoint args) throws Throwable {
        PageBean pageBean = null;
        //获取目标方法的所有参数
        Object[] ars = args.getArgs();
        for (Object param : ars) {
            if(param instanceof PageBean){
                pageBean = (PageBean)param;
                break;
            }
        }

        if(pageBean != null && pageBean.isPagination())
            PageHelper.startPage(pageBean.getPage(),pageBean.getRows());

        Object list = args.proceed();

        if(null != pageBean && pageBean.isPagination()){
            PageInfo pageInfo = new PageInfo((List) list);
            pageBean.setTotal((int) pageInfo.getTotal());
        }
        return list;
    }

}

2.2 工具类

package com.YU.utils;

import javax.servlet.http.HttpServletRequest;
import java.io.Serializable;
import java.util.Map;

public class PageBean implements Serializable {

	private static final long serialVersionUID = 2422581023658455731L;

	//页码
	private int page=1;
	//每页显示记录数
	private int rows=10;
	//总记录数
	private int total=0;
	//是否分页
	private boolean isPagination=true;
	//上一次的请求路径
	private String url;
	//获取所有的请求参数
	private Map<String,String[]> map;
	
	public PageBean() {
		super();
	}
	
	//设置请求参数
	public void setRequest(HttpServletRequest req) {
		String page=req.getParameter("page");
		String rows=req.getParameter("rows");
		String pagination=req.getParameter("pagination");
		this.setPage(page);
		this.setRows(rows);
		this.setPagination(pagination);
		this.url=req.getContextPath()+req.getServletPath();
		this.map=req.getParameterMap();
	}
	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}

	public Map<String, String[]> getMap() {
		return map;
	}

	public void setMap(Map<String, String[]> map) {
		this.map = map;
	}

	public int getPage() {
		return page;
	}

	public void setPage(int page) {
		this.page = page;
	}
	
	public void setPage(String page) {
		if(null!=page&&!"".equals(page.trim()))
			this.page = Integer.parseInt(page);
	}

	public int getRows() {
		return rows;
	}

	public void setRows(int rows) {
		this.rows = rows;
	}
	
	public void setRows(String rows) {
		if(null!=rows&&!"".equals(rows.trim()))
			this.rows = Integer.parseInt(rows);
	}

	public int getTotal() {
		return total;
	}

	public void setTotal(int total) {
		this.total = total;
	}
	
	public void setTotal(String total) {
		this.total = Integer.parseInt(total);
	}

	public boolean isPagination() {
		return isPagination;
	}
	
	public void setPagination(boolean isPagination) {
		this.isPagination = isPagination;
	}
	
	public void setPagination(String isPagination) {
		if(null!=isPagination&&!"".equals(isPagination.trim()))
			this.isPagination = Boolean.parseBoolean(isPagination);
	}
	
	/**
	 * 获取分页起始标记位置
	 * @return
	 */
	public int getStartIndex() {
		//(当前页码-1)*显示记录数
		return (this.getPage()-1)*this.rows;
	}
	
	/**
	 * 末页
	 * @return
	 */
	public int getMaxPage() {
		int totalpage=this.total/this.rows;
		if(this.total%this.rows!=0)
			totalpage++;
		return totalpage;
	}
	
	/**
	 * 下一页
	 * @return
	 */
	public int getNextPage() {
		int nextPage=this.page+1;
		if(this.page>=this.getMaxPage())
			nextPage=this.getMaxPage();
		return nextPage;
	}
	
	/**
	 * 上一页
	 * @return
	 */
	public int getPreivousPage() {
		int previousPage=this.page-1;
		if(previousPage<1)
			previousPage=1;
		return previousPage;
	}

	@Override
	public String toString() {
		return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", isPagination=" + isPagination
				+ "]";
	}
}

3.编写biz层

package com.YU.biz;

import com.YU.model.HBook;
import com.YU.utils.PageBean;

import java.util.List;

public interface HBookbiz {
    int deleteByPrimaryKey(Integer bid);

    int insert(HBook record);

    int insertSelective(HBook record);

    HBook selectByPrimaryKey(Integer bid);

    int updateByPrimaryKeySelective(HBook record);

    int updateByPrimaryKey(HBook record);

    List<HBook> listPager(HBook hBook, PageBean pageBean);
}

注：

这个方法为查询返回列表方法，包含分页，因为切面类对其进行切面，所以在命名时，必须以Pager结尾

4.配置mapper.xml

<select id="selectBycon" resultType="com.YU.model.HBook" parameterType="com.YU.model.HBook" >
    select
    <include refid="Base_Column_List" />
    from t_mvc_book
    <where>
        <if test="bname != null">
            and bname like concat('%',#{bname},'%')
        </if>
    </where>
  </select>

5.编写相应的接口类（HBookMapper）

    List<HBook> selectBycon(HBook hBook);

6.处理controller层发送到biz的请求(配置spring-mvc.xml)

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
      http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
      http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
      http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">
    <!--1) 扫描com.YU.web及子子孙孙包下的控制器(扫描范围过大，耗时)-->
    <context:component-scan base-package="com.YU"/>

    <!--2) 此标签默认注册DefaultAnnotationHandlerMapping和AnnotationMethodHandlerAdapter -->
    <mvc:annotation-driven />

    <!--3) 创建ViewResolver视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!-- viewClass需要在pom中引入两个包：standard.jar and jstl.jar -->
        <property name="viewClass"
                  value="org.springframework.web.servlet.view.JstlView"></property>
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--4) 单独处理图片、样式、js等资源 -->
    <!-- <mvc:resources location="/css/" mapping="/css/**"/>
     <mvc:resources location="/js/" mapping="/js/**"/>
     <mvc:resources location="WEB-INF/images/" mapping="/images/**"/>-->
    <!--处理controller层发送请求到biz，会经过切面的拦截处理-->
    <aop:aspectj-autoproxy/>
</beans>

7.编写tag助手标签类

package com.YU.tag;

import java.io.IOException;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.BodyTagSupport;

import com.YU.utils.PageBean;

public class PageTag extends BodyTagSupport{
	private PageBean pageBean;// 包含了所有分页相关的元素
	
	public PageBean getPageBean() {
		return pageBean;
	}

	public void setPageBean(PageBean pageBean) {
		this.pageBean = pageBean;
	}

	@Override
	public int doStartTag() throws JspException {
//		没有标签体，要输出内容
		JspWriter out = pageContext.getOut();
		try {
			out.print(toHTML());
		} catch (IOException e) {
			e.printStackTrace();
		}
		return super.doStartTag();
	}

	private String toHTML() {
		StringBuffer sb = new StringBuffer();
//		隐藏的form表单---这个就是上一次请求下次重新发的奥义所在
//		上一次请求的URL
		sb.append("<form action='"+pageBean.getUrl()+"' id='pageBeanForm' method='post'>");
		sb.append("	<input type='hidden' name='page'>");
//		上一次请求的参数
		Map<String, String[]> paramMap = pageBean.getMap();
		if(paramMap != null && paramMap.size() > 0) {
			Set<Entry<String, String[]>> entrySet = paramMap.entrySet();
			for (Entry<String, String[]> entry : entrySet) {
//				参数名
				String key = entry.getKey();
//				参数值
				for (String value : entry.getValue()) {
//					上一次请求的参数，再一次组装成了新的Form表单
//					注意：page参数每次都会提交，我们需要避免
					if(!"page".equals(key)) {
						sb.append("	<input type='hidden' name='"+key+"' value='"+value+"' >");
					}
				}
			}
		}
		sb.append("</form>");
		
//		分页条
		sb.append("<ul class='pagination justify-content-center'>");
		sb.append("	<li class='page-item "+(pageBean.getPage() == 1 ? "disabled" : "")+"'><a class='page-link'");
		sb.append("	href='javascript:gotoPage(1)'>首页</a></li>");
		sb.append("	<li class='page-item "+(pageBean.getPage() == 1 ? "disabled" : "")+"'><a class='page-link'");
		sb.append("	href='javascript:gotoPage("+pageBean.getPreivousPage()+")'>&lt;</a></li>");// less than 小于号
//		sb.append("	<li class='page-item'><a class='page-link' href='#'>1</a></li>");
//		sb.append("	<li class='page-item'><a class='page-link' href='#'>2</a></li>");
		sb.append("	<li class='page-item active'><a class='page-link' href='#'>"+pageBean.getPage()+"</a></li>");
		sb.append("	<li class='page-item "+(pageBean.getPage() == pageBean.getMaxPage() ? "disabled" : "")+"'><a class='page-link' href='javascript:gotoPage("+pageBean.nextPage()+")'>&gt;</a></li>");
		sb.append("	<li class='page-item "+(pageBean.getPage() == pageBean.getMaxPage() ? "disabled" : "")+"'><a class='page-link' href='javascript:gotoPage("+pageBean.maxPage()+")'>尾页</a></li>");
		sb.append("	<li class='page-item go-input'><b>到第</b><input class='page-link'");
		sb.append("	type='text' id='skipPage' name='' /><b>页</b></li>");
		sb.append("	<li class='page-item go'><a class='page-link'");
		sb.append("	href='javascript:skipPage()'>确定</a></li>");
		sb.append("	<li class='page-item'><b>共"+pageBean.getTotal()+"条</b></li>");
		sb.append("</ul>");
		
//		分页执行的JS代码
		sb.append("<script type='text/javascript'>");
		sb.append("	function gotoPage(page) {");
		sb.append("		document.getElementById('pageBeanForm').page.value = page;");
		sb.append("		document.getElementById('pageBeanForm').submit();");
		sb.append("	}");
		sb.append("	function skipPage() {");
		sb.append("		var page = document.getElementById('skipPage').value;");
		sb.append("		if (!page || isNaN(page) || parseInt(page) < 1 || parseInt(page) > "+pageBean.getMaxPage()+") {");
		sb.append("			alert('请输入1~"+pageBean.getMaxPage()+"的数字');");
		sb.append("			return;");
		sb.append("		}");
		sb.append("		gotoPage(page);");
		sb.append("	}");
		sb.append("</script>");
		
		return sb.toString();
	}
}

8.引入tld标签库

<?xml version="1.0" encoding="UTF-8" ?>

<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
    version="2.0">
    
  <description>YU 1.1 core library</description>
  <display-name>YU core</display-name>
  <tlib-version>1.1</tlib-version>
  <short-name>YU</short-name>
  <uri>http://jsp.veryedu.cn</uri>
  
  
  <tag>
    <name>page</name>
    <tag-class>com.YU.tag.PageTag</tag-class>
    <body-content>JSP</body-content>
    <attribute>
        <name>pageBean</name>
        <required>true</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
  </tag>
  
</taglib>

9.编写controller类

package com.YU.web;

import com.YU.biz.HBookbiz;
import com.YU.model.HBook;
import com.YU.utils.PageBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;

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

/**
 * @author YU
 * @create 2023-09-07 16:07
 */
@Controller
@RequestMapping("book")
public class HbookController {

    @Autowired
    private HBookbiz hBookbiz;

    //增加
    @RequestMapping("/add")
    public String add(HBook hBook){
         hBookbiz.insertSelective(hBook);
        return "redirect:/book/list";
    }
    //删除
    @RequestMapping("/del/{bid}")
    public String del(@PathVariable("bid")Integer bid){
        hBookbiz.deleteByPrimaryKey(bid);
        return "redirect:/book/list";
    }
    //修改
    @RequestMapping("/edit")
    public String edit(HBook hBook){
        hBookbiz.updateByPrimaryKeySelective(hBook);
        return "redirect:list";
    }
    //查询
    @RequestMapping("/list")
    public String list(HBook hBook, HttpServletRequest request){
//        hbook用来接收前台传递后台的参数
        PageBean pageBean = new PageBean();
        pageBean.setRequest(request);
        List<HBook> hBooks = hBookbiz.listPager(hBook, pageBean);
        request.setAttribute("lst",hBooks);
        request.setAttribute("pageBean",pageBean);
        return "book/list";
    }
    //数据回显
    @RequestMapping("/preSave")
    public String preSave(HBook hBook, Model model){
        if(hBook !=null && hBook.getBid()!=null && hBook.getBid()!=0){
            HBook b = hBookbiz.selectByPrimaryKey(hBook.getBid());
            model.addAttribute("b",b);
        }
        return "book/edit";
    }
}

10.编写前端页面

1.主页面(展示数据进行操作)

<%@ page language="java" contentType="text/html; charset=UTF-8"
         pageEncoding="UTF-8"%>
<%@ taglib uri="http://jsp.veryedu.cn" prefix="z"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <link
            href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.css"
            rel="stylesheet">
    <script
            src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/js/bootstrap.js"></script>
    <title>博客列表</title>
    <style type="text/css">
        .page-item input {
            padding: 0;
            width: 40px;
            height: 100%;
            text-align: center;
            margin: 0 6px;
        }

        .page-item input, .page-item b {
            line-height: 38px;
            float: left;
            font-weight: 400;
        }

        .page-item.go-input {
            margin: 0 10px;
        }
    </style>
</head>
<body>
<form class="form-inline"
      action="${pageContext.request.contextPath }/book/list" method="get">
    <div class="form-group mb-2">
        <input type="text" class="form-control-plaintext" name="cname"
               placeholder="请输入班级名称">
        <!-- 			<input name="rows" value="20" type="hidden"> -->
        <!-- 不想分页 -->
        <%--        <input name="pagination" value="false" type="hidden">--%>
    </div>
    <button type="submit" class="btn btn-primary mb-2">查询</button>
    <a class="btn btn-primary mb-2" href="${pageContext.request.contextPath }/book/preSave">新增</a>
</form>

<table class="table table-striped">
    <thead>
    <tr>
        <th scope="col">书籍ID</th>
        <th scope="col">书籍名称</th>
        <th scope="col">书籍价格</th>
<%--        <th scope="col">班级图片</th>--%>
        <th scope="col">操作</th>
    </tr>
    </thead>
    <tbody>
    <c:forEach  var="b" items="${lst }">
        <tr>
            <td>${b.bid }</td>
            <td>${b.bname }</td>
            <td>${b.price }</td>
            <td>
                <a href="${pageContext.request.contextPath }/book/preSave?bid=${b.bid}">修改</a>
                <a href="${pageContext.request.contextPath }/book/del/${b.bid}">删除</a>
            </td>
        </tr>
    </c:forEach>
    </tbody>
</table>
<!-- 这一行代码就相当于前面分页需求前端的几十行了 -->
<z:page pageBean="${pageBean }"></z:page>
${pageBean }
</body>
</html>

2.增加修改界面(操作数据)

<body>
<form action="${pageContext.request.contextPath }/${empty b ? 'book/add' : 'book/edit'}" method="post">
    cid:<input type="text" name="bid" value="${b.bid }"><br>
    bname:<input type="text" name="bname" value="${b.bname }"><br>
    price:<input type="text" name="price" value="${b.price }"><br>
    <input type="submit">
</form>
</body>

3.测试结果

感谢各位大大的收看，各位的支持和三连是博主更新的动力，感谢谢谢谢！！！！