用jersey ＋ spring 实现rest服务及单元测试

jersey提供了强大的rest功能，可以通过简洁的标注和编码实现业务的需求，架构会透明的把你的pojo对象转化为客户端可以接受的json/xml文件模式，当然也可以用它做一些基于ajax的表单提交和下载功能，这里简单说下他在spirng中的设置

在pom中引入

        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-json</artifactId>
            <version>1.17.1</version>
        </dependency>
        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-core</artifactId>
            <version>1.17.1</version>
        </dependency>

        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-core-asl</artifactId>
            <version>1.9.13</version>
        </dependency>
        <dependency>
            <groupId>com.sun.jersey.contribs</groupId>
            <artifactId>jersey-spring</artifactId>
            <version>1.17.1</version>
        </dependency>

在 web.xml里面配置,其中com.sun.jersey.config.property.packages属性设置我们的rest对外的业务类所在的包，本事例对外输出json为主，所以设置POJOMappingFeature 为true。url-parttern 和 org.codehaus.enunciate.modules.jersey.config.ServletPath 设置rest的url的前缀，例如下面的为127.0.0.1/rest/xxxxx

com.sun.jersey.spi.spring.container.servlet.SpringServlet 这个为jersey 在spring中的路由统一处理模块

    <servlet>
        <servlet-name>jersey</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>mypackage.jersey.resource</param-value>
        </init-param>
        <init-param>
            <param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
            <param-value>true</param-value>
        </init-param>
        <init-param>
            <param-name>com.sun.jersey.spi.container.ContainerRequestFilters</param-name>
            <param-value>com.sun.jersey.api.container.filter.PostReplaceFilter</param-value>
        </init-param>
        <init-param>
            <param-name>org.codehaus.enunciate.modules.jersey.config.ServletPath</param-name>
            <param-value>/rest</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>jersey</servlet-name>
        <url-pattern>/rest/*</url-pattern>
    </servlet-mapping>

咱们在刚才定义的 com.sun.jersey.config.property.packages 里面写一个 rest服务类

import java.awt.PageAttributes.MediaType;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;


@Component
@Path("/demo")
@Produces({ "application/json" })
public class DemoRest {    
    @GET
    public DemoResult getDemo(@Context HttpServletRequest req) {
        DemoResult dr = new DemoResult("test", 19);
        return dr;
    }

    @GET
    @Path("name/{name}")
    public DemoResult getDemo1(@PathParam("name") String name) {
        DemoResult dr = new DemoResult(name, 19);
        return dr;
    }
}

其中 DemoResult 为：

public class DemoResult {
    private String name;
    private int age;
    public DemoResult(String name, int age) {
        this.name = name;
        this.age = age;
    }    
}

启动服务后，运行 127.0.0.1/rest/demo  (对应getDemo)或者 127.0.0.1/rest/demo/name/hello (对应 getDemo1)就可以得到我们需要的json结果了

单元测试：

配置pom:

        <dependency>
            <groupId>com.sun.jersey.jersey-test-framework</groupId>
            <artifactId>jersey-test-framework-core</artifactId>
            <version>1.17.1</version>
        </dependency>
        <dependency>
            <groupId>com.sun.jersey.jersey-test-framework</groupId>
            <artifactId>jersey-test-framework-grizzly2</artifactId>
            <version>1.17.1</version>
        </dependency>

我们写一个测试基类，其中 mypackage.jersey.resource 为提供rest服务的类所在的包，例如上面的DemoRest所在的包。其他的配置和web.xml中jersey的配置参数一一对应

import javax.ws.rs.core.Application;

import junit.framework.TestCase;

import org.junit.BeforeClass;
import org.junit.runner.RunWith;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.request.RequestContextListener;
import org.unitils.database.annotations.Transactional;
import org.unitils.spring.annotation.SpringApplicationContext;
import org.unitils.UnitilsJUnit4TestClassRunner;
import org.unitils.database.util.TransactionMode;

import com.sun.jersey.spi.spring.container.servlet.SpringServlet;
import com.sun.jersey.test.framework.WebAppDescriptor;public abstract class BaseJerseyServiceTest extends com.sun.jersey.test.framework.JerseyTest {
    @Override
    protected WebAppDescriptor configure() {
        return  new WebAppDescriptor.Builder("mypackage.jersey.resource")
        .contextParam( "contextConfigLocation", "classpath:JApplicationContext.xml")
        .servletClass(SpringServlet.class)
        .initParam("com.sun.jersey.api.json.POJOMappingFeature", "true")
        .initParam("com.sun.jersey.spi.container.ContainerRequestFilters", "com.sun.jersey.api.container.filter.PostReplaceFilter")
        .contextListenerClass(ContextLoaderListener.class)
        .requestListenerClass(RequestContextListener.class)
        .build();
    }
}

我们用这个测试类写一个测试用例的半成品，其中params是模拟的get/post参数.运行即可。例子中测试的是 /shopInfo/trend?type=pv 这个rest请求

public class ShopInfoTest extends BaseJerseyServiceTest {    

    private final static Logger logger = LoggerFactory
            .getLogger(ShopInfoTest.class);

    @Test
    public void test() {
        WebResource webResource = resource();
        webResource.accept("application/json");
        MultivaluedMap<String, String> params = new MultivaluedMapImpl();
        params.add("type", "pv");
        String response = webResource
                .path("/shopInfo/trend")
                .queryParams(params)
                .get(String.class);
        System.out.println(response.toString());
    }
}