springmvc知识点

╰+哭是因爲堅強的太久メ 2024-04-06 09:51 56阅读 0赞

1.![8c7c20dcc8164b51a1bdafc02e7960b8.png][]

ServletContext

对于一个web应用，其部署在web容器中，web容器提供其一个全局的上下文环境，这个上下文就是我们的ServletContext，其为后面的spring IoC容器提供一个宿主环境

spring上下文,springmvc上下文

springMVC容器只负责创建Controller对象，不会创建service和dao，并且他是一个子容器。而spring的容器只负责Service和dao对象，是一个父容器。子容器可以看见父容器的对象，而父容器看不见子容器的对象，这样各司其职。

2.url匹配优先级

![5cfba0a2d1534c798bf18f4541fb8e1a.png][]

不论有多少个/\*/\*,都比/\*\*优先级高.

当有多个\*和多个‘\{\}'时，命中单个路径多的，优先越高。

前缀匹配优先级低,比非前缀的低

\*,\{\}越少优先级越高

路径越短优先级越高

3.form表单出现中文乱码,在web.xml文件添加如下过滤器

<filter>
            <filter-name>CharacterEncodingFilter</filter-name>
            <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
            <init-param>
                <param-name>encoding</param-name>
                <param-value>UTF-8</param-value>
            </init-param>
        </filter>
        <filter-mapping>
            <filter-name>CharacterEncodingFilter</filter-name>
            <url-pattern>/*</url-pattern>
        </filter-mapping>

4.在idea中测试http响应可以在test文件夹下新建一个user.http(只要以.http结尾就行),格式和帮助文档在建立该文件后,右上角会提示,具体文档全文如下

### Send POST request with json body
    POST https://httpbin.org/post
    Content-Type: application/json
    
    {
      "id": 999,
      "value": "content"
    }
    
    ### Send POST request with body as parameters
    POST https://httpbin.org/post
    Content-Type: application/x-www-form-urlencoded
    
    id=999&value=content
    
    ### Send a form with the text and file fields
    POST https://httpbin.org/post
    Content-Type: multipart/form-data; boundary=WebAppBoundary
    
    --WebAppBoundary
    Content-Disposition: form-data; name="element-name"
    Content-Type: text/plain
    
    Name
    --WebAppBoundary
    Content-Disposition: form-data; name="data"; filename="data.json"
    Content-Type: application/json
    
    < ./request-form-data.json
    --WebAppBoundary--
    
    ### Send request with dynamic variables in request's body
    POST https://httpbin.org/post
    Content-Type: application/json
    
    {
      "id": {
       {$uuid}},
      "price": {
       {$randomInt}},
      "ts": {
       {$timestamp}},
      "value": "content"
    }
    
    ###

5.当需要传递复杂参数的时候,需要建立一个vo类,专门用于传参

@Data
    public class QueryVo {
        private String sortField;
        private User user;
        private Long[] ids;
        private List<User> userList;
        private Map<String, User> userMap;
    }

6.entity对象的属性应该保持和数据库中的字段名完全一致.

7.越靠近po,复用度越低

8.![213dbd84b4a748ceb9c111aa7be722b7.png][]

9.避免每次添加新的包都手动引入的办法: project settings->artifacts->左上加号->WEBapplication EXPLORED ->第二个选项(from module) 然后重新部署tomcat, configuration->Deployment 然后reload下maven

10.thymeleaf 乱码,添加第二行

11. 上传文件时,要在springmvc的配置文件中添加如下内容(application.xml)

<bean id="multipartResolver"
              class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
            
            <property name="maxUploadSize" value="17367648787"></property>
    
            
            <property name="defaultEncoding" value="UTF-8"></property>
    </bean>

同时要注意表单的名字和controller中的

@RequestParam("textFile") 的参数要一致

public R upload(@RequestParam("textFile") CommonsMultipartFile file){

[8c7c20dcc8164b51a1bdafc02e7960b8.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/06/34698b55f70943759d425e21f058e99e.png
[5cfba0a2d1534c798bf18f4541fb8e1a.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/06/4c71f47f74bc4b99ac15fa3f5e55d2e4.png
[213dbd84b4a748ceb9c111aa7be722b7.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/06/947823da109d427fba28afc18ba24829.png