SpringMVC of Java framework

Spring MVC series of teaching materials (1)-Tutorial

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Must read: Framework-based programs must run successfully. For the version of the JAR package and the correctness of the configuration file, there are strict requirements. Anything wrong will cause the framework program to fail. If you are learning this framework for the first time, be sure to strictly follow the instructions of the tutorial and completely imitate the operation until you successfully see the running effect. After the first success, confidence and ideas will have a good foundation, and then according to their doubts, make the original changes and adjustments to the "successful" code, which can greatly save the time of learning and improve efficiency Do n’t make changes without permission, creating obstacles to your own learning

Step 1: first run, to see the effect, re-learning
Step 2: imitate and troubleshooting
Step 3: Create project springmvc
Step 4: introducing jar package
Step 5: web.xml
Step 6: Create springmvc-servlet.xml
Step 7: Control class IndexController
step 8: prepare index.jsp
step 9: deploy in the tomcat restart testing
step 10: schematic
step 11: Download the complete project
step 12: exercise

Step 1: Run first, see the effect, then learn

Spring MVC needs to do a lot of steps. If any step is missed or wrong, it may fail, which will affect the confidence of learning and mistakenly believe that this tutorial will not work.

So first download the download area (https://how2j.cn/p/5329) can run the project springmvc.rar, unpacked into eclipse, start Tomcat, see if functioning properly. Make sure you can run, make sure the tutorial can run, and then learn the following content.

For the method of importing into Eclipse and running, please refer to: After importing a dynamic Web project into Eclipse and

deploying successfully, test the address and you should see the effect as shown in the figure

http: //127.0.0.1:8080/springmvc/index

Note: This is a dynamic project format does not support an independent way to deploy Tomcat

Step 2: imitate and troubleshoot

After ensuring that the runnable project runs correctly, follow the steps of the tutorial strictly and imitate the code again.
The imitation process will inevitably lead to discrepancies in the code, resulting in the inability to obtain the expected operating results. At this moment, by comparing the correct answer (runnable item) and your own code, you can locate the problem.
In this way, learning is effective and troubleshooting is efficient, which can significantly improve the learning speed and cross the threshold of learning.

It is recommended to use diffmerge software for folder comparison. Compare your own project folder with my executable project folder.
This software is very fast hardware, you can know which of the two file folder wrong, and clearly marked
here provides installation and use of green Tutorial: DiffMerge download and tutorial

Step 3: Create project springmvc

Create a new project springmvc in eclipse, using dynamic web project. Students who are not familiar with this method, please refer to  the way to develop J2EE applications using Dynamic Web Project

Step 4: import jar package

Download download area (click to enter) lib.rar and copy it to unzip e: / project / springmvc / WebContent / WEB-INF / lib directory

Step 5: web.xml

Created under the WEB-INF directory web.xml

configuration entries DispatcherServlet Spring MVC, and all requests are submitted to the Servlet

Note: <the servlet-name> SpringMVC </ the servlet-name>

SpringMVC This name will be used in the next step

<? xml  version = "1.0"  encoding = "UTF-8" ?> < web-app  version = "2.4"  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-app_2_4.xsd">      < servlet >          < servlet-name >springmvc</ servlet-name >          < servlet-class >              org.springframework.web.servlet.DispatcherServlet          </ servlet-class >          < load-on-startup >1</ load-on-startup >      </ servlet >      < servlet-mapping >          < servlet-name >springmvc</ servlet-name >          < url-pattern >/</ url-pattern >      </ servlet-mapping > </ web-app >

Step 6: create springmvc-servlet.xml

Create springmvc-servlet.xml
springmvc-servlet.xml in the WEB-INF directory and the previous step

<servlet-name>springmvc</servlet-name>

springmvc corresponds

This is Spring MVC profile map
showing access paths / index will give indexController the process id = bean
id = indexController bean configuration of the class: IndexController

<? xml  version = "1.0"  encoding = "UTF-8"  ?> <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"> < beans >      < bean  id = "simpleUrlHandlerMapping"          class = "org.springframework.web.servlet.handler.SimpleUrlHandlerMapping" >          < property  name = "mappings" >              < props >                  < prop  key = "/index" >indexController</ prop >              </ props >          </ property >      </ bean >      < bean  id = "indexController"  class = "controller.IndexController" ></ bean > </ beans >

Step 7: Control class IndexController

The control class IndexController implements the interface Controller and provides the method handleRequest to process the request.

Spring MVC combines the model and the view through the ModelAndView object

ModelAndView mav =  new  ModelAndView( "index.jsp" ); mav.addObject( "message" ,  "Hello Spring MVC" );

Indicates that the view is index.jsp The
model data is message, and the content is "Hello Spring MVC"

package  controller;   import  javax.servlet.http.HttpServletRequest; import  javax.servlet.http.HttpServletResponse;   import  org.springframework.web.servlet.ModelAndView; import  org.springframework.web.servlet.mvc.Controller;   public  class  IndexController  implements  Controller {      public  ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response)  throws  Exception {          ModelAndView mav =  new  ModelAndView( "index.jsp" );          mav.addObject( "message" ,  "Hello Spring MVC" );          return  mav;      } }

Step 8: prepare index.jsp

Create index.jsp in the WebContent directory

index.jsp is very simple, display the content of the message through the EL expression

<%@ page language="java" contentType="text/html; charset=UTF-8"      pageEncoding="UTF-8" isELIgnored="false"%>   < h1 >${message}</ h1 >

Step 9: Deploy in tomcat, restart test

Deploy in Tomcat, restart tomcat, and then visit the address to observe the effect

http: //127.0.0.1:8080/springmvc/index

For the deployment method, please refer  to Tomcat-Run On Server via Eclipse

步骤 10 : 原理图

1. 用户访问 /index
2. 根据web.xml中的配置 所有的访问都会经过DispatcherServlet
3. 根据 根据配置文件springmvc-servlet.xml ，访问路径/index
会进入IndexController类
4. 在IndexController中指定跳转到页面index.jsp，并传递message数据
5. 在index.jsp中显示message信息

步骤 11 : 完整的项目下载

一般说来，根据步骤一步一步的做过来，就可以运行看到结果了。
如果实在看不到结果，多半是因为中间某个步骤不够仔细，大小写错误，多了个下划线等等细微的错误。

如果是这样，还可以在右侧下载完整的项目保证一定可以走通

步骤 12 : 练习

本例实现了访问路径/index，服务端跳转到index.jsp的效果

练习：访问路径/hello 服务端跳转到hello.jsp

More SpringMVC learning content: https://how2j.cn/k/springmvc/springmvc-springmvc/615.html?p=144217