问题
When I am running test at that time @Autowired is working but when I run the web app and try to fetch data at that time its throwing null pointer exception.
this is my controller
In this BuyerRepo is always null
import com.retail.exception.InvalidIdException;
import com.retail.model.Buyer;
import com.retail.repository.BuyerRepo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
@Path("/buyer")
@Component
public class BuyerController {
@Autowired
private BuyerRepo buyerRepo;
@GET
@Produces("application/json")
public Buyer searchFields() throws InvalidIdException {
String buyerId = "51";
Buyer buyer;
try {
buyer = buyerRepo.getBuyer(Long.parseLong(buyerId));
} catch (NumberFormatException e) {
buyer = buyerRepo.getBuyer(buyerId);
}
return buyer;
}
}
In repository entity manager is always null
this is buyerRepository
import com.retail.exception.InvalidIdException;
import com.retail.model.Buyer;
import org.springframework.stereotype.Repository;
import javax.persistence.NoResultException;
@Repository
public class BuyerRepo extends AbstractRepository {
public Buyer getBuyer(String buyerName) throws InvalidIdException {
javax.persistence.Query buyerId = entityManager.createNativeQuery("select b.buyer_id from buyer b where b.name = :name").setParameter("name", buyerName);
Integer id;
try {
id = (Integer) buyerId.getSingleResult();
} catch (NoResultException e) {
return null;
}
return getBuyer(id);
}
public Buyer getBuyer(long buyerId) throws InvalidIdException {
Buyer buyer = entityManager.find(Buyer.class, buyerId);
if (buyer == null) throw new InvalidIdException("Invalid Article ID");
return buyer;
}
}
this is applicationContext.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:tx="http://www.springframework.org/schema/tx" xmlns:mvc="http://www.springframework.org/schema/mvc"
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/tx
http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
<context:annotation-config/>
<context:component-scan base-package="com.retail"/>
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="org.postgresql.Driver"/>
<property name="url" value="jdbc:postgresql://localhost/retail"/>
<property name="username" value="retail_user"/>
<property name="password" value="password"/>
</bean>
<bean id="entityManagerOne" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="packagesToScan" value="com.retail"/>
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="showSql" value="true"/>
<property name="databasePlatform" value="org.hibernate.dialect.PostgreSQLDialect"/>
</bean>
</property>
</bean>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerOne"/>
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
</beans>
this is servlet-context.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"
xsi:schemaLocation="http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
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">
<mvc:annotation-driven />
<context:annotation-config />
<context:component-scan base-package="com.retail" />
</beans>
this is web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 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_5.xsd">
<servlet>
<servlet-name>retail</servlet-name>
<servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
<init-param>
<param-name>com.sun.jersey.config.property.packages</param-name>
<param-value>com.retail.web</param-value>
</init-param>
<init-param>
<param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
<param-value>true</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>retail</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
classpath:applicationContext.xml
/WEB-INF/servlet-context.xml
</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<listener>
<listener-class>org.springframework.web.context.request.RequestContextListener</listener-class>
</listener>
<welcome-file-list>
<welcome-file>/WEB-INF/views/index.jsp</welcome-file>
</welcome-file-list>
</web-app>
回答1:
You can try using the SpringServlet instead of the jersey provided servlet container to achieve Jersey-Spring integration.
<servlet-class>com.sun.jersey.spi.spring.container.servlet.SpringServlet</servlet-class>
The documentation for this class states :
A servlet or filter for deploying root resource classes with Spring integration. This class extends ServletContainer and initiates the WebApplication with a Spring-based IoCComponentProviderFactory, SpringComponentProviderFactory, such that instances of resource and provider classes declared and managed by Spring can be obtained. Classes of Spring beans declared using XML-based configuration or auto-wire-based confguration will be automatically registered if such classes are root resource classes or provider classes. It is not necessary to provide initialization parameters for declaring classes in the web.xml unless a mixture of Spring-managed and Jersey- managed classes is required. The servlet supports configuration of child applicationContexts, see CONTEXT_CONFIG_LOCATION.
回答2:
I Have encountered this situation, you need to add some jar file
gradle project：
compile group: 'org.glassfish.jersey.ext', name: 'jersey-spring3', version: '2.22.2'
maven project:
<dependency>
<groupId>org.glassfish.jersey.ext</groupId>
<artifactId>jersey-spring3</artifactId>
<version>2.22.2</version>
</dependency>
another solution is web.xml file:
<servlet>
<servlet-name>jersey-serlvet</servlet-name>
<servlet-class>com.sun.jersey.spi.spring.container.servlet.SpringServlet</servlet-class>
<init-param>
<param-name>com.sun.jersey.config.property.packages</param-name>
<param-value>cn.ice</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>jersey-serlvet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
回答3:
You have to wire a interface instead of class. so there are two ways:
To let BuyerRepo to implement one interface
Useing @Inject or @Resource instead of @Autowired
回答4:
Looks like your buyerRepo has no public setter. It's also not possible to set it through the constructor. How about write a setter for it and put the @Autowired annotation on the setter instead. Like this:
@Repository
public class BuyerRepo extends AbstractRepository {
private BuyerRepo buyerRepo;
@Autowired
public void setBuyerRepo(BuyerRepo buyerRepo)
{
this.buyerRepo = buyerRepo;
}
//...Other code is omitted.
}
来源：https://stackoverflow.com/questions/16622148/autowired-is-not-working-with-jersey-and-spring