SpringMVC学习总结

SprngMVC学习总结

HelloSpringMvc遇到的问题

• Tomcat中没有相应的jar包,需要导入!
• controller在注册时的id,就是url中的参数,需要保持一致

使用注解进行开发

<!--    自动扫描包，让指定包下的注解生效-->
    <context:component-scan base-package="com.huzai.controller"/>
<!--    让SpringMVC不处理静态资源-->
    <mvc:default-servlet-handler/>
<!--    自动注入-->
    <mvc:annotation-driven/>

RestFull风格

url路径中参数的携带

@RequestMapping(value = "/add/{a}/{b}", method = RequestMethod.GET)
public String add(@PathVariable int a,@PathVariable int b, Model model){
    int result = a+b;
    model.addAttribute("msg",result);
    return "hello";
}

JSON的使用

jackson

• 依赖(需要将其jar包导入tomcat的依赖)

  <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.11.3</version>
  </dependency>

• 使用(可以在大环境下使用@RestController)

  @RequestMapping("/json")
  @ResponseBody
  public String json() throws JsonProcessingException {
      ObjectMapper objectMapper = new ObjectMapper();
      Date date = new Date();
      String str = objectMapper.writeValueAsString(date);
      return str;
  }

fastjson

• 依赖

  <dependency>
         <groupId>com.alibaba</groupId>
         <artifactId>fastjson</artifactId>
         <version>1.2.73</version>
     </dependency>

• 使用

      @RequestMapping("/fastJson")
      @ResponseBody
      public String fastJson(){
  //        fastJson 有很多功能其实都可以用jackson扩展写
  //        java对象转JSON字符串JSON.toJSONString
  //        JSON字符串转JAVA对象JSON.parseObject()
  
          Date date = new Date();
          String json = JSON.toJSONString(date);
          return json;
      }

乱码问题

Web中的乱码

• 在web.xml中进行配置

<filter>
    <filter-name>encoding</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>encoding</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

Jackson中的乱码

• 在springMVC的配置文件中进行配置

<!--    自动注入,JSON乱码问题配置-->
<mvc:annotation-driven>
    <mvc:message-converters register-defaults="true">
        <bean class="org.springframework.http.converter.xml.SourceHttpMessageConverter"/>
        <bean class="org.springframework.http.converter.cbor.MappingJackson2CborHttpMessageConverter">
            <property name="objectMapper">
                <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                    <property name="failOnEmptyBeans" value="false"/>
                </bean>
            </property>
        </bean>
    </mvc:message-converters>
</mvc:annotation-driven>

fastjson中的乱码

<mvc:annotation-driven>
    <mvc:message-converters>
        <bean class="org.springframework.http.converter.StringHttpMessageConverter">
            <property name="supportedMediaTypes">
                <list>
                    <value>application/json;charset=UTF-8</value>
                </list>
            </property>
        </bean>
    </mvc:message-converters>
</mvc:annotation-driven>

springMVC中的全部配置文件

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<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_4_0.xsd"
         version="4.0">
    <servlet>
        <servlet-name>springMVC</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springMVC</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <filter>
        <filter-name>encoding</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>



</web-app>

Springmvc-servlet.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:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       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.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
    <!--    自动扫描包，让指定包下的注解生效-->
    <context:component-scan base-package="com.huzai.controller"/>
    <!--    让SpringMVC不处理静态资源-->
    <mvc:default-servlet-handler/>
    <!--    自动注入,JSON乱码问题配置-->
    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean class="org.springframework.http.converter.xml.SourceHttpMessageConverter"/>
            <bean class="org.springframework.http.converter.cbor.MappingJackson2CborHttpMessageConverter">
                <property name="objectMapper">
                    <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                        <property name="failOnEmptyBeans" value="false"/>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>