How to configure Jersey with Spring using only annotations - spring

Question

I have a Servlet 3.0 web app that uses both Spring and Jersey. I currently have it set up using the SpringServlet configured as a filter in web.xml, and the resource classes annotated with both #Path and #Component. Here's the web.xml snippet:
<filter>
<filter-name>jersey-serlvet</filter-name>
<filter-class>
com.sun.jersey.spi.spring.container.servlet.SpringServlet
</filter-class>
<init-param>
<param-name>
com.sun.jersey.config.property.packages
</param-name>
<param-value>com.foo;com.bar</param-value>
</init-param>
<init-param>
<param-name>com.sun.jersey.config.feature.FilterForwardOn404</param-name>
<param-value>true</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>jersey-serlvet</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
This setup works, but I really want to get this set up with annotations only - no web.xml config. My first attempt at this was to remove the above SpringServlet configuration and create a class that extends Application. Here's a snippet of that:
#ApplicationPath("/*")
public class MyApplication extends PackagesResourceConfig {
public MyApplication() {
super("com.foo;com.bar");
HashMap<String, Object> settings = new HashMap<String, Object>(1);
settings.put(ServletContainer.FEATURE_FILTER_FORWARD_ON_404, true);
this.setPropertiesAndFeatures(settings);
}
}
This works in that the JAX-RS resources are registered and I can hit them at their URLs, but they throw NullPointerExceptions when they try and use their autowired properties... this makes sense because I'm guessing the resources are now being loaded by Jersey and are not Spring managed beans, therefore no autowiring.
Despite a fair bit of searching around I cannot find any way of loading the Jersey resources as Spring beans with annotations only. Is there such a way? I don't really want to have to write a bunch of code for the resources to manually fetch the Spring context and invoke the DI if I can help it.
If annotations-only isn't going to work, then I can live with the filter config in web.xml if I can specify an Application class to load instead of a list of packages to scan. If I can get rid of the package list in there and just specify an Application class instance then I'll be content.
Obviously it would be great if someone had a definitive answer for me but I'd also be grateful for any pointers or hints of where else I could look or things to try.
Thanks,
Matt

Answer 1

Below is part of my app, which uses Servlet 3.0, Spring, Jersey 1.8 and it has no web.xml:
public class WebAppInitializer implements WebApplicationInitializer {
#Override
public void onStartup(ServletContext servletContext) throws ServletException {
final AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
context.setConfigLocation("com.myapp.config");
final FilterRegistration.Dynamic characterEncodingFilter = servletContext.addFilter("characterEncodingFilter", new CharacterEncodingFilter());
characterEncodingFilter.addMappingForUrlPatterns(EnumSet.allOf(DispatcherType.class), true, "/*");
characterEncodingFilter.setInitParameter("encoding", "UTF-8");
characterEncodingFilter.setInitParameter("forceEncoding", "true");
final FilterRegistration.Dynamic springSecurityFilterChain = servletContext.addFilter("springSecurityFilterChain", new DelegatingFilterProxy());
springSecurityFilterChain.addMappingForUrlPatterns(EnumSet.allOf(DispatcherType.class), true, "/*");
servletContext.addListener(new ContextLoaderListener(context));
servletContext.setInitParameter("spring.profiles.default", "production");
final SpringServlet servlet = new SpringServlet();
final ServletRegistration.Dynamic appServlet = servletContext.addServlet("appServlet", servlet);
appServlet.setInitParameter("com.sun.jersey.config.property.packages", "com.myapp.api");
appServlet.setInitParameter("com.sun.jersey.spi.container.ContainerRequestFilters", "com.myapp.api.SizeLimitFilter");
appServlet.setLoadOnStartup(1);
final Set<String> mappingConflicts = appServlet.addMapping("/api/*");
if (!mappingConflicts.isEmpty()) {
throw new IllegalStateException("'appServlet' cannot be mapped to '/' under Tomcat versions <= 7.0.14");
}
}
}

Answer 2

I haven't been able to get my ideal result but I have been able to make some progress, so I'll post here in case it helps anyone else. I was able to use the Spring Servlet to specify my application class, thereby removing the package list from the web.xml.
The web.xml changes required are in the init params (the filter mapping is not shown but is still required):
<filter>
<filter-name>jersey-serlvet</filter-name>
<filter-class>
com.sun.jersey.spi.spring.container.servlet.SpringServlet
</filter-class>
<init-param>
<param-name>javax.ws.rs.Application</param-name> <!-- Specify application class here -->
<param-value>com.foo.MyApplication</param-value>
</init-param>
</filter>
And then in the application class I had to change the way I called the super constructor slightly:
public MyApplication() {
super("com.foo", "com.bar"); // Pass in packages as separate params
HashMap<String, Object> settings = new HashMap<String, Object>(1);
settings.put(ServletContainer.FEATURE_FILTER_FORWARD_ON_404, true);
this.setPropertiesAndFeatures(settings);
}
Still not exactly what I was after but at least this pulls a little more config into Java code and out of the web.xml, which is important for me as I'm trying to hide this detail.

Answer 3

Two options spring to mind (no pun intended).
Maybe you could extend SpringServlet with your own class and add appropriate servlet 3.0 annotations to it.
Going along with your approach of switching from the SpringServlet to an Application class, you could solve the no-autowiring problem by enabling Spring build-time or load-time bytecode weaving. That enables Spring to inject objects instantiated by anywhere instead of only objects created by Spring. See "Using AspectJ to dependency inject domain objects with Spring".

Answer 4

First of all, in a servlet 3.0 container you don't really need a web.xml.
But with Jersey 2.0 you can set a flag to scan the whole web app for annotated resources:
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet>
<servlet-name>jersey</servlet-name>
<servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
<init-param>
<param-name>jersey.config.servlet.provider.webapp</param-name>
<param-value>true</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
Spring will be enabled automatically if you include this jar:
<dependency>
<groupId>org.glassfish.jersey.ext</groupId>
<artifactId>jersey-spring3</artifactId>
<version>2.3.1</version>
</dependency>

Answer 5

I used Jersey with my previously made project using SpringMVC. I based my code on the Spring's official documentation.
public class WebAppInitializer implements WebApplicationInitializer {
#Override
public void onStartup(ServletContext servletContext) {
// Don't create the Listener that Jersey uses to create.
// There can only be one linstener
servletContext.setInitParameter("contextConfigLocation", "<NONE>");
AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
// Add app config packages
context.setConfigLocation("config.package");
// Add listener to the context
servletContext.addListener(new ContextLoaderListener(context));
// Replacing:
// <servlet-name>ServletName</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>webservices.packages</param-value>
// </init-param>
// <load-on-startup>1</load-on-startup>
AnnotationConfigWebApplicationContext dispatcherContext = new AnnotationConfigWebApplicationContext();
ServletRegistration.Dynamic appServlet = servletContext.addServlet("ServletName", new DispatcherServlet(dispatcherContext));
appServlet.setInitParameter("com.sun.jersey.config.property.packages", "org.sunnycake.aton.controller");
appServlet.setLoadOnStartup(1);
appServlet.addMapping("/RootApp");
}
}
The configuration classes in config.package are:
// Specifies that there will be bean methods annotated with #Bean tag
// and will be managed by Spring
#Configuration
// Equivalent to context:component-scan base-package="..." in the xml, states
// where to find the beans controlled by Spring
#ComponentScan(basePackages = "config.package")
public class AppConfig {
/**
* Where will the project views be.
*
* #return ViewResolver como el XML
*/
#Bean
public ViewResolver viewResolver() {
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
return viewResolver;
}
}
Hibernate configuration
// Specifies that there will be bean methods annotated with #Bean tag
// and will be managed by Spring
#Configuration
// Equivalent to Spring's tx in the xml
#EnableTransactionManagement
// Equivalent to context:component-scan base-package="..." in the xml, states
// where to find the beans controlled by Spring
#ComponentScan({"config.package"})
// Here it can be stated some Spring properties with a properties file
#PropertySource(value = {"classpath:aplicacion.properties"})
public class HibernateConfig {
/**
* Inyected by Spring based on the .properties file in the
* \#PropertySource tag.
*/
#Autowired
private Environment environment;
/**
* Here it's created a Session Factory, equivalent to the Spring's config file one.
*
* #return Spring Session factory
*/
#Bean
public LocalSessionFactoryBean sessionFactory() {
LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();
// Uses the datasource
sessionFactory.setDataSource(dataSource());
// Indicates where are the POJOs (DTO)
sessionFactory.setPackagesToScan(new String[]{"dto.package"});
// Se asignan las propiedades de Hibernate
sessionFactory.setHibernateProperties(hibernateProperties());
return sessionFactory;
}
/**
* Propiedades de la base de datos (Según environment)
*
* #return Nuevo DataSource (Configuración de la base de datos)
*/
#Bean
public DataSource dataSource() {
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName(environment.getRequiredProperty("jdbc.driverClassName"));
dataSource.setUrl(environment.getRequiredProperty("jdbc.url"));
dataSource.setUsername(environment.getRequiredProperty("jdbc.username"));
dataSource.setPassword(environment.getRequiredProperty("jdbc.password"));
return dataSource;
}
/**
* Hibernate properties
*
* #return Properties set with the configuration
*/
private Properties hibernateProperties() {
Properties properties = new Properties();
// Dialect (Mysql, postgresql, ...)
properties.put("hibernate.dialect", environment.getRequiredProperty("hibernate.dialect"));
// Show SQL query
properties.put("hibernate.show_sql", environment.getRequiredProperty("hibernate.show_sql"));
properties.put("hibernate.format_sql", environment.getRequiredProperty("hibernate.format_sql"));
return properties;
}
/**
* Inyected by sessionFactory
*/
#Bean
#Autowired
public HibernateTransactionManager transactionManager(SessionFactory s) {
HibernateTransactionManager txManager = new HibernateTransactionManager();
txManager.setSessionFactory(s);
return txManager;
}
}

Answer 6

This is a full example. First of all - don't use any web.xml. Use only code below.
Rest resource:
#Path("hello")
public class HelloResource {
#GET
#Produces(MediaType.TEXT_PLAIN)
public Response hello() {
String output = "Hello World!";
return Response.status(200).entity(output).build();
}
}
Rest application (note "core" in package name)
#ApplicationPath("rest")
public class RestApplication extends javax.ws.rs.core.Application {
public RestApplication() {
}
#Override public Set<Class<?>> getClasses() {
return Set.of(
HelloResource.class
);
}
}
Spring web configuration.
#Configuration
#EnableWebMvc
#ComponentScan(basePackageClasses = {
})
public class WebConfig implements WebMvcConfigurer {
private static final Logger logger = LoggerFactory.getLogger(WebConfig.class);
#Autowired
private ApplicationContext applicationContext;
public WebConfig() {
}
}
Spring initializer
//This #Order is required!!!
#Order(Ordered.HIGHEST_PRECEDENCE)
public class MyWebInitializer implements WebApplicationInitializer {
#Override
public void onStartup(ServletContext servletContext) throws ServletException {
var ctx = new AnnotationConfigWebApplicationContext();
//spring WebMvcConfigurer
ctx.register(WebConfig.class);
ctx.setServletContext(servletContext);
//Spring servlet
var servlet = servletContext.addServlet("dispatcher", new DispatcherServlet(ctx));
servlet.setLoadOnStartup(1);
servlet.addMapping("/");
// Register Jersey 2.0 servlet
ServletRegistration.Dynamic jerseyServlet = servletContext.addServlet("jerseyServlet",
"org.glassfish.jersey.servlet.ServletContainer");
//note "javax.ws.rs.Application" doesn't have "core"
jerseyServlet.setInitParameter("javax.ws.rs.Application", RestApplication.class.getName());
jerseyServlet.addMapping("/rest/*");
jerseyServlet.setLoadOnStartup(1);
}
}
And it must work on, for example, http://127.0.0.1:8080/rest/hello