How to debug 404 resource not found in spring mvc rest?

Question

I have a sample spring rest mvc application which has the following java code:

SampleController.java

import org.apache.logging.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("sample")
public class SampleController {
        @RequestMapping(method = RequestMethod.GET, produces = "application/json")
        @ResponseBody
        public String getBatches()//@RequestParam(name = "name", required = true) String name)
        {
                return "Hello ";
        }
}

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>ved</groupId>
    <artifactId>platform</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>platform Maven Webapp</name>
    <url>http://maven.apache.org</url>
    <properties>
        <spring.version>4.2.1.RELEASE</spring.version>
        <jackson.version>2.6.2</jackson.version>
        <spring-boot.version>1.2.6.RELEASE</spring-boot.version>
        <filter.name>DEV</filter.name>
        <jersey.version>1.9</jersey.version>
        <base.directory>${basedir}</base.directory>
    </properties>
    <profiles>
        <profile>
            <id>local</id>
            <activation>
                <property>
                    <name>env</name>
                    <value>local</value>
                </property>
            </activation>
            <properties>
                <filter.name>DEV</filter.name>
            </properties>
        </profile>
        <profile>
            <id>qa</id>
            <activation>
                <property>
                    <name>env</name>
                    <value>qa</value>
                </property>
            </activation>
            <properties>
                <filter.name>QA</filter.name>
            </properties>
        </profile>
        <profile>
            <id>prod</id>
            <activation>
                <property>
                    <name>env</name>
                    <value>prod</value>
                </property>
            </activation>
            <properties>
                <filter.name>PROD</filter.name>
            </properties>
        </profile>
    </profiles>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>

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

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>${jackson.version}</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>${jackson.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-mongodb</artifactId>
            <version>1.8.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.3</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.3</version>
        </dependency>
        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-core</artifactId>
            <version>${jersey.version}</version>
        </dependency>

        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-client</artifactId>
            <version>${jersey.version}</version>
        </dependency>
        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.2.4</version>
        </dependency>
        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-server</artifactId>
            <version>${jersey.version}</version>
        </dependency>
    </dependencies>
    <build>
        <!-- <filters> <filter>${basedir}/src/main/resources/ENV-${filter.name}/application.properties</filter> 
            </filters> -->
        <finalName>platform</finalName>

        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <debug>true</debug>
                    <debuglevel>source,lines</debuglevel>
                    <showDeprecation>true</showDeprecation>
                    <archive>
                    </archive>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.5</version>
                <configuration>
                    <systemPropertyVariables>
                        <environment>prod</environment>
                    </systemPropertyVariables>
                </configuration>
            </plugin>
            <plugin>
                <groupId>com.google.code.maven-svn-revision-number-plugin</groupId>
                <artifactId>maven-svn-revision-number-plugin</artifactId>
                <version>1.7</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>revision</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <entries>
                        <entry>
                            <prefix>svn</prefix>
                        </entry>
                    </entries>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>buildnumber-maven-plugin</artifactId>
                <version>1.0</version>
                <executions>
                    <execution>
                        <id>generate-timestamp</id>
                        <phase>validate</phase>
                        <goals>
                            <goal>create-timestamp</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <format>{0,date,yyyy-MM-dd HH:mm}</format>
                    <items>
                        <item>timestamp</item>
                    </items>
                </configuration>
            </plugin>
        </plugins>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>
</project>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    id="WebApp_ID" version="3.0">

    <display-name>Archetype Created Web Application</display-name>

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

    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

dispatcher-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:beans="http://www.springframework.org/schema/beans"
    xmlns:util="http://www.springframework.org/schema/util" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mongo="http://www.springframework.org/schema/data/mongo"
    xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/mvc 
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-4.0.xsd
http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd
http://www.springframework.org/schema/data/mongo
http://www.springframework.org/schema/data/mongo/spring-mongo-1.0.xsd">

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

    <context:annotation-config />
    <context:component-scan base-package="com.ved.platform" />

    <bean id="jacksonMessageConverter"
        class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter" />

    <bean
        class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
        <property name="messageConverters">
            <list>
                <ref bean="jacksonMessageConverter" />
            </list>
        </property>
    </bean>
    <bean
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix">
            <value>/WEB-INF/views/</value>
        </property>
        <property name="suffix">
            <value>.jsp</value>
        </property>
    </bean>

    <!-- <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter"> 
        <property name="messageConverters"> <list> <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"> 
        </bean> </list> </property> </bean> -->

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

    <mvc:annotation-driven />

</beans>

homepage is giving me the apache page, but once I try to access 127.0.0.1:8080/sample It throws me a 404 error. Logs are all silent about it. Not sure how to fix this.

Answer 1

Place a breakpoint in

org.springframework.web.servlet.mvc.condition.PatternsRequestCondition.getMatchingPattern(String pattern, String lookupPath).

You will see why there is no match for your request.

Answer 2

Make sure you're scanning the packages your controllers are in. Otherwise spring won't create beans for your controllers and the paths they're listening for will return a 404.