json - 在 DIspatcherServlet 中找不到映射

Question

几天来我一直在与这条消息作斗争，无法弄清楚我错在哪里。

基本上我想做的是在我的服务中提供 json。我对返回 jsp 不感兴趣。

我请求的网址是

localhost/service/products/1

这里是错误。

WARN - No mapping found for HTTP request with URI [/service/products/1] in DispatcherServlet with name 'cr'

我的 ProductsController 显示如下:

package com.cr.controllers;

import com.cr.dao.ProductsDao;
import com.cr.entity.Products;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.servlet.ServletResponse;
import java.io.IOException;

/**
 * User: ChappleZ
 * Date: 2/17/13
 * Time: 8:21 PM
 */
@Controller
@RequestMapping(value = "/service")
public class ProductsController {
    private static final Logger log = LoggerFactory.getLogger(ProductsController.class);
    @Autowired
    private ProductsDao productsDao;

    @RequestMapping(method = RequestMethod.GET)
    public void get(ServletResponse response) throws IOException {
        response.setContentType("text/plain");
        response.getWriter().print("My Products dao: " + productsDao);
    }

    @RequestMapping(value = "/products/{productId}",
            headers="Accept=application/json",
            method = RequestMethod.GET)
    public
    @ResponseBody
    Products findByProductId(@PathVariable Long productId) {
        Products products = productsDao.getProductsById(productId);
        return products;
    }
}

应用环境:

<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:jpa="http://www.springframework.org/schema/data/jpa"
       xmlns:jdbc="http://www.springframework.org/schema/jdbc"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd
        http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.0.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
       ">
    <context:annotation-config />
    <jpa:repositories base-package="com.cr" />

    <!--   // JPA specific configuration here: dataSource, persistenceUnitManager exceptionTranslator, entityManagerFactory, SessionFactory, transactionManager - should not be relevant for this problem, tell me if i'm wrong-->

    <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />

    <bean id="productsDao" class="com.cr.dao.impl.ProductsDaoImpl"/>

    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="persistenceUnitName" value="spring-jpa"/>
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <property name="showSql" value="true"/>
                <property name="generateDdl" value="true"/>
                <property name="database" value="MYSQL"/>
            </bean>
        </property>
    </bean>

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
    </bean>

    <tx:annotation-driven/>

    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/crcart3"/>
        <property name="username" value="root"/>
        <property name="password" value=""/>
    </bean>
</beans>

网络.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <display-name>cr</display-name>
    <description>cr</description>
    <context-param>
        <param-name>log4jConfigLocation</param-name>
        <param-value>classpath:log4j.xml</param-value>
    </context-param>

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
            classpath:applicationContext.xml
        </param-value>
    </context-param>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>


    <servlet>
        <servlet-name>cr</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/conf/spring-controllers.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>cr</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <filter>
        <filter-name>httpMethodFilter</filter-name>
        <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>httpMethodFilter</filter-name>
        <servlet-name>cr</servlet-name>
    </filter-mapping>

    <session-config>
        <session-timeout>15</session-timeout>
    </session-config>

    <error-page>
        <error-code>401</error-code>
        <location>/error/401</location>
    </error-page>
    <error-page>
        <error-code>404</error-code>
        <location>/error/404</location>
    </error-page>
    <error-page>
        <error-code>500</error-code>
        <location>/error/500</location>
    </error-page>
    <error-page>
        <error-code>504</error-code>
        <location>/error/504</location>
    </error-page>
    <error-page>
        <exception-type>java.lang.Throwable</exception-type>
        <location>/error/500</location>
    </error-page>

</web-app>

Spring-Controllers.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:util="http://www.springframework.org/schema/util"
       xmlns:jee="http://www.springframework.org/schema/jee"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:oxm="http://www.springframework.org/schema/oxm"
       xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd
        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.0.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
        http://www.springframework.org/schema/oxm http://www.springframework.org/schema/oxm/spring-oxm-3.0.xsd">

    <context:property-placeholder location="classpath:config.properties"/>

    <context:component-scan base-package="com.cr"/>

    <bean id="jsonConverter" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
        <property name="supportedMediaTypes" value="application/json"/>
    </bean>

    <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
        <property name="messageConverters">
            <list>
                <ref bean="jsonConverter"/>
            </list>
        </property>
    </bean>

    <mvc:resources mapping="/resources/**" location="/resources/"/>

</beans>

此外，如果它有帮助，这也会显示 404 页面的相同警告。

WARN - No mapping found for HTTP request with URI [/service/products/1] in DispatcherServlet with name 'cr'
WARN - No mapping found for HTTP request with URI [/error/404] in DispatcherServlet with name 'cr'

Answer 1

我看到的三个问题:

1. 在 web.xml 中，您的 DispatcherServlet 应该映射到 /*而不仅仅是 / .后者仅匹配空路径而不匹配其他任何内容，因此您请求的路径永远不会命中 servlet。
2. 您离开了 <mvc:annotation-driven/>从你的 spring-controller.xml 中。
3. 在您的 spring-controllers.xml 中可能不相关，但肯定会导致 future 的问题，您不应该像在 applicationContext.xml 中那样对相同的基础包进行组件扫描。 spring-controllers.xml 用于配置您的 DispatcherServlet，并且应该只包含 Controller 和与 MVC 相关的 bean。 applicationContext.xml 是您的服务、DAO 和相关事物应该存在的地方。这与此处描述的问题相同:

Declaring Spring Bean in Parent Context vs Child Context

有关在 Spring MVC 中配置 Spring 上下文的正确方法的更多说明，请访问:

Why DispatcherServlet creates another application context?