SpringMVC入门

1. 什么是springMVC?
Spring Web MVC是一种基于Java的实现了MVC设计模式的、请求驱动类型的、轻量级Web框架。

2. SpringMVC处理请求的流程
2.1 首先用户发送请求-->DispatherServlet
2.2 DispatcherServlet-->HandlerMapping
2.3 DispatcherServlet-->HandlerAdapter
2.4 HandlerAdapter-->处理器功能处理方法的调用
2.5 ModelAndView的逻辑视图名-->ViewRecolver
2.6 View-->渲染
2.7 返回控制权给DispatcherServlet，由DispatcherServlet返回呼应给用户，流程结束

3. SpringMVC核心开发步骤
3.1 DispatcherServlet在web.xml中的部署描述，从而拦截请求到springMVC
3.2 HandlerMapping的配置，从而将请求映射到处理器
3.3 HandlerAdapter的配置，从而支持多种类型的处理器
3.4 处理器(页面控制器)的配置，从而刊行功能处理
3.5 ViewResolver的配置，从而将逻辑视图名解析为具体的视图技术

4. SpringMVC的组件
4.1 前端控制器(DispatcherServlet)
4.2 请求到处理器映射(HandlerMapping)
4.3 处理器适配器(HandlerAdapter)
4.4 视图解析器(ViewResolver)
4.5 处理器或页面控制器(Controller)
4.6 验证器(Validator)
4.6 命令对象(Command 请求参数绑定到的对象就叫命令对象)
4.7 表单对象(Form Object提供给表单展示和提交到的对象就叫表单对象)

5. 常用注解
5.1 @Controller：用于标识处理器类

5.2 @RequestMapping：请求到处理器功能方法的映射规则，可定义到类和方法
常用参数：value、method
可将@RequestMapping标签定义到类名处窄化路径

5.3 @RequestParam：请求参数到处理器功能处理方法的方法参数上的绑定
常用参数：value、required、defaultValue
注：required设置成false的参数类型必须是引用类型，因为基本数据类型是不能为null的

5.4 @ModelAttribute：请求参数到命令对象的绑定
常用参数：value
5.4.1 可用@ModelAttribute标注方法参数，方法参数会被添加到Model对象中(作用：向视图层传数据)
5.4.2 可用@ModelAttribute标注一个非请求处理方法，此方法会在每次调用请求处理方法前被调用(作用：数据初始化)
5.4.3 可用@ModelAttribute标注方法，方法返回值会被添加到Model对象中(作用：向视图层传数据)
但此方法视图的逻辑图就会根据请求路径解析，例如：a/test42 --> /WEB-INF/a/test42.jsp
太麻烦几乎不用，不用直接保存到Model或ModelAndView中

5.5 @SessionAttributes：指定ModelMap中的哪些属性需要转存到session
常用参数：value、types
注1：必须放到class类名处

5.6 @InitBinder(本章暂不介绍)：用于将请求参数转换到命令对象属性的对应类型

5.7 @RequestBody(重要~~~~~)：用于目前比较流行的ajax开发的数据绑定(即提交数据的类型为json格式)
注1：使用@RequestBody注解的时候，前台的Content-Type必须要改为application/json，
如果没有更改，前台会报错415（Unsupported Media Type）。
后台日志就会报错Content type ‘application/x-www-form-urlencoded;charset=UTF-8’ not supported。
这些错误Eclipse下Tomcat是不会显示错误信息的，只有使用了日志才会显示

如何在项目中添加springmvc

添加相关依赖

 <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>${spring.version}</version>
      </dependency>

<dependency>
          <groupId>jstl</groupId>
          <artifactId>jstl</artifactId>
          <version>1.2</version>
      </dependency>
      <dependency>
          <groupId>taglibs</groupId>
          <artifactId>standard</artifactId>
          <version>1.1.2</version>
      </dependency>

在WEB-INF下添加springmvc-servlet.xml(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:mvc="http://www.springframework.org/schema/mvc" xmlns:aop="http://www.springframework.org/schema/aop"
       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/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
    <!-- 通过context:component-scan元素扫描指定包下的控制器-->
    <!--1) 扫描com.javaxl.zf及子子孙孙包下的控制器(扫描范围过大，耗时)-->
    <!--开启动态代理-->
    <aop:aspectj-autoproxy/>
    <context:component-scan base-package="com.liuwenwu"/>

    <!--2) 此标签默认注册DefaultAnnotationHandlerMapping和AnnotationMethodHandlerAdapter -->
    <!--两个bean，这两个bean是spring MVC为@Controllers分发请求所必须的。并提供了数据绑定支持，-->
    <!--@NumberFormatannotation支持，@DateTimeFormat支持，@Valid支持，读写XML的支持（JAXB），读写JSON的支持（Jackson）-->
    <!--开启注解驱动-->
    <mvc:annotation-driven></mvc:annotation-driven>

    <!--3) 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="/"/>
        <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="/static/" mapping="/static/**"/>
    <!--<mvc:resources location="/js/" mapping="/js/**"/>-->


</beans>

修改web.xml

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
  <display-name>Archetype Created Web Application</display-name>

  <welcome-file-list>
    <welcome-file>login.jsp</welcome-file>
  </welcome-file-list>

  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:applicationContext.xml</param-value>
  </context-param>
  <!-- 读取Spring上下文的监听器 -->
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  <!-- Spring和web项目集成end -->

  <!-- 防止Spring内存溢出监听器 -->
  <listener>
    <listener-class>org.springframework.web.util.IntrospectorCleanupListener</listener-class>
  </listener>

  <!-- 中文乱码处理 -->
  <filter>
    <filter-name>encodingFilter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <!--web.xml 3.0的新特性，是否支持异步-->
    <async-supported>true</async-supported>
    <init-param>
      <param-name>encoding</param-name>
      <param-value>UTF-8</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>encodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

  <!-- Spring MVC servlet -->
  <servlet>
    <servlet-name>SpringMVC</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <!--此参数可以不配置，默认值为：/WEB-INF/springmvc-servlet.xml-->
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>/WEB-INF/springmvc-servlet.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
    <!--web.xml 3.0的新特性，是否支持异步-->
    <async-supported>true</async-supported>
  </servlet>
  <servlet-mapping>
    <servlet-name>SpringMVC</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

</web-app>

Springmvc之helloword实现

第一个springMVC程序：HelloWorld
HelloController

package com.liuwenwu.controller;

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

import javax.servlet.http.HttpServletRequest;

/**
 * @author LWW
 * @site www.lww.com
 * @company
 * @create 2019-09-28 11:01
 *
 * 关于结果集处理的五种情况
 * 1、转发到页面(webapp下)
 * 2、转发到action
 * 3、重定向到页面(webapp下)
 * 4、重定向到action
 * 5、转发到 WEB-INF下的页面
 */

@Controller
public class HelloController {

    /**
     * 转发到页面
     * @param request
     * @return
     */
    @RequestMapping("hello")
    public String hello(HttpServletRequest request){
        request.setAttribute("msg","转发到页面的方式");
        return "hello";
    }


    /**
     * 重定向到action
     * @param request
     * @return
     */
    @RequestMapping("hello2")
    public String redirectPage(HttpServletRequest request){
        request.setAttribute("msg","重定向到action的方式");
        return "redirect:hello";
    }

    /**
     * 重定向到页面
     * @param request
     * @return
     */
    @RequestMapping("hello3")
    public String redirectPage2(HttpServletRequest request){
//        request.setAttribute("msg","重定向到页面的方式");
        Object msg = request.getAttribute("msg");
        return "redirect:/hello.jsp";
    }

    /**
     * 转发到action
     * @param request
     * @return
     */
    @RequestMapping("hello4")
    public String forwardAction(HttpServletRequest request){
        request.setAttribute("msg","转发到action的方式");
        return "forward:hello3";
    }

    /**
     * 转发到WEB-INF下的页面
     * @param request
     * @return
     */
    @RequestMapping("hello5")
    public String forwardAction2(HttpServletRequest request){
        request.setAttribute("msg","转发到WEB-INF下的页面方式");
        return "abc";
    }
}

hello.ksp

<%--
  Created by IntelliJ IDEA.
  User: ASUS
  Date: 2019/9/28
  Time: 11:03
  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>
hello springmvc xxx
<hr>
${msg}
</body>
</html>

效果：

Springmvc常用注解及返回值处理

CRUD案例

BookController

package com.liuwenwu.controller;

import com.liuwenwu.model.Book;
import com.liuwenwu.service.BookService;
import com.liuwenwu.util.PageBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;

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

/**
 * @author LWW
 * @site www.lww.com
 * @company
 * @create 2019-09-28 11:43
 */

@Controller
@RequestMapping("/book")  //命名空间
public class BookController {

    @Autowired
    private BookService bookService;

    /**
     * postman
     * swagger2
     * 查询展示
     * @param book
     * @param request
     * @return
     *
     */

    @RequestMapping("/list")
    public String list(Book book, HttpServletRequest request){
        PageBean pageBean =new PageBean();
        pageBean.setRequest(request);
        List<Map> list = this.bookService.listPager(book, pageBean);
        request.setAttribute("bookList",list);
        request.setAttribute("pageBean",pageBean);
        return "bookList";
    }

    /**
     * 跳转新增或修改页面
     * @param book
     * @param request
     * @return
     */
    @RequestMapping("/preSave")
    public String preSave(Book book, HttpServletRequest request){
        if(book.getBid() !=null){
            Book b = this.bookService.selectByPrimaryKey(book.getBid());
            request.setAttribute("b",b);
        }
        return "bookEdit";
    }

    /**
     * 新增
     * @param book
     * @param request
     * @return
     */
    @RequestMapping("/add")
    public String add(Book book, HttpServletRequest request){
        this.bookService.insert(book);
        return "redirect:/book/list"; //重定向
    }

    /**
     * 删除
     * @param bid
     * @param request
     * @return
     */
    @RequestMapping("/del/{bid}")
    public String del(@PathVariable(value = "bid") Integer bid, HttpServletRequest request){
        this.bookService.deleteByPrimaryKey(bid);
        return "redirect:/book/list";
    }

    /**
     * 修改
     * @param book
     * @param request
     * @return
     */
    @RequestMapping("/edit")
    public String edit(Book book, HttpServletRequest request){
        this.bookService.updateByPrimaryKeySelective(book);
        return "redirect:/book/list";
    }
}

bookList.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
     <%@ taglib uri="/zking" prefix="z" %>
<!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>Insert title here</title>
<script type="text/javascript">
    function add(){
        // window.location.href = "bookEdit.jsp";
        window.location.href="${pageContext.request.contextPath}/book/preSave";
    }
    
    function update(bid){
        window.location.href = "${pageContext.request.contextPath}/book/preSave?bid="+bid;
    }
    
    function del(bid){
        window.location.href = "${pageContext.request.contextPath}/book/del/"+bid;
    }
</script>
</head>
<body>
    <form action="${pageContext.request.contextPath}/book/list"
        method="post">
        书名：<input type="text" name="bname"> <input type="submit"
            value="确定">
    </form>
    <button onclick="add();">新增</button>
    <table border="1" width="100%">
        <tr>
            <td>编号</td>
            <td>名称</td>
            <td>价格</td>
            <td>操作</td>
        </tr>
        <c:forEach items="${bookList }" var="b">
            <tr>
                <td>${b.bid }</td>
                <td>${b.bname }</td>
                <td>${b.price }</td>
                <td>
                    <button onclick="update(${b.bid });">修改</button>&nbsp;&nbsp;&nbsp;
                    <button onclick="del(${b.bid });">删除</button>
                </td>
            </tr>
        </c:forEach>
    </table>
    <z:page pageBean="${pageBean }"></z:page>
</body>
</html>

bookEdit.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>Insert title here</title>
<script type="text/javascript">
    function doSubmit(bid){
        var bookForm = document.getElementById("bookForm");
        if(bid){
            //修改时候执行
            bookForm.action = '${pageContext.request.contextPath}/book/edit';

        }else{
            //新增时候执行
            bookForm.action = '${pageContext.request.contextPath}/book/add';
        }
        bookForm.submit();
    }
</script>
</head>
<body>
    <form id="bookForm" action="" method="post">
        bid:<input type="text" name="bid" value="${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" value="提交" onclick="doSubmit('${b.bid }');"><br>
    </form>
</body>
</html>

PageTag

package com.liuwenwu.util;


import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.BodyTagSupport;
import java.io.IOException;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;


public class PageTag extends BodyTagSupport {

    private static final long serialVersionUID = 1L;
    private PageBean pageBean;
    public PageBean getPageBean() {
        return pageBean;
    }
    public void setPageBean(PageBean pageBean) {
        this.pageBean = pageBean;
    }
    @Override
    public int doStartTag() throws JspException {
        JspWriter out = pageContext.getOut();
        try {
            out.print(toHTML());
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return super.doStartTag();
    }
    private String toHTML() {
        StringBuffer sb = new StringBuffer();
        /*
         * 拼接向后台提交数据的form表单
         *     注意：拼接的form表单中的page参数是变化的，所以不需要保留上一次请求的值
         */
        sb.append("<form id='pageBeanForm' action='"+pageBean.getUrl()+"' method='post'>");
        sb.append("<input type='hidden' name='page'>");
        Map<String, String[]> parameterMap = pageBean.getMap();
        if(parameterMap != null && parameterMap.size() > 0) {
            Set<Entry<String, String[]>> entrySet = parameterMap.entrySet();
            for (Entry<String, String[]> entry : entrySet) {
                if(!"page".equals(entry.getKey())) {
                    String[] values = entry.getValue();
                    for (String val : values) {
                        sb.append("<input type='hidden' name='"+entry.getKey()+"' value='"+val+"'>");
                    }
                }
            }
        }
        sb.append("</form>");
        
        /*
         * 展示的分页条
         */
        sb.append("<div style='text-align: right; font-size: 12px;'>");
        sb.append("每页"+pageBean.getRows()+"条，共"+pageBean.getTotal()+"条，第"+pageBean.getPage()+"页，共"+pageBean.getMaxPage()+"页&nbsp;&nbsp;<a href='javascript:gotoPage(1)'>首页</a>&nbsp;&nbsp;<a");
        sb.append(" href='javascript:gotoPage("+pageBean.getPreivousPage()+")'>上一页</a>&nbsp;&nbsp;<a");
        sb.append(" href='javascript:gotoPage("+pageBean.getNextPage()+")'>下一页</a>&nbsp;&nbsp;<a");
        sb.append(" href='javascript:gotoPage("+pageBean.getMaxPage()+")'>尾页</a>&nbsp;&nbsp;<input type='text'");
        sb.append(" id='skipPage'");
        sb.append(" style='text-align: center; font-size: 12px; width: 50px;'>&nbsp;&nbsp;<a");
        sb.append(" href='javascript:skipPage()'>Go</a>");
        sb.append("</div>");
        
        /*
         * 给分页条添加与后台交互的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~N的数字');");
        sb.append("                return;");
        sb.append("            }");
        sb.append("            gotoPage(page);");
        sb.append("        }");
        sb.append("</script>");
        return sb.toString();
    }
}

效果：

Springmvc静态资源处理

在webapp下建一个static静态资源包存放一张图片

springmvc-servlet.xml

 <!--4) 单独处理图片、样式、js等资源 -->
    <!--<mvc:resources location="/css/" mapping="/css/**"/>-->
    <mvc:resources location="/static/" mapping="/static/**"/>
    <!--<mvc:resources location="/js/" mapping="/js/**"/>-->

效果：

posted on 2019-09-28 22:47 骑猪南下L 阅读(200) 评论(0) 编辑收藏举报