将 @PathParam 传递给 Jersey 中的子资源定位器 class

Question

我想这样调用我的 api 端点：

http://.../companies/1/employees

并使用代码 1 检索公司的员工。我有这个代码：

@Path("companies")
public class CompanyResource {

    @Context
    ResourceContext resourceContext;

    @GET
    @Path("{idCompany}/employees")
    public EmployeeResource getEmployees() {
        return resourceContext.getResource(EmployeeResource.class);
    }

}

和

@Path("/employees")
public class EmployeeResource {

    @PathParam("idCompany")
    String idCompany;

    @GET
    public List<Employee> getEmployees() {
        // here "idCompany" is null
        //some code
    }
}

但是路径参数为空。我究竟做错了什么？有更正确的方法吗？

Answer 1

我这样使用路径参数

@GET
public List<Employee> getEmployees(@PathParam("idCompany") String id ) {
    // here "idCompany" is null
    //some code
}

Answer 2

我通常是这样做的:

@Path("companies")
public class CompanyResource {

    @GET
    @Path("{idCompany}/employees")
    public EmployeeResource getEmployees(@PathParam("idCompany") String idCompany) {
       // ...
    }

}

或

@Path("companies/{idCompany}/employees")
public class EmployeeResource {

    @PathParam("idCompany")
    String idCompany;

    @GET
    public List<Employee> getEmployees() {
       //
    }
}

第二个示例中的 @PathParam 为空，因为为了将其注入字段，服务 class 上的 @Path 注释必须有一个部分声明 {idCompany} @PathParam.

Answer 3

我无法重现 null id，但有几点需要指出

@GET 应该从 EmployeeResource getEmployees() 方法中删除。子资源定位器不应该有 HTTP 方法注释。参见 Sub-resources
EmployeeResource 上的 @Path 也被忽略（不需要）。没问题，只是觉得你应该知道。

下面是使用 Jersey Test Framework 的完整工作示例。这是我使用的测试依赖项

<dependency>
    <groupId>org.glassfish.jersey.test-framework.providers</groupId>
    <artifactId>jersey-test-framework-provider-grizzly2</artifactId>
    <version>${jersey2.version}</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-json-jackson</artifactId>
    <version>${jersey2.version}</version>
    <scope>test</scope>
</dependency>

您可以运行它像任何其他 JUnit 测试一样

import java.util.ArrayList;
import java.util.List;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.container.ResourceContext;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import org.glassfish.jersey.server.ResourceConfig;
import org.glassfish.jersey.test.JerseyTest;
import org.junit.Test;
import static junit.framework.Assert.*;

public class LocatorTest extends JerseyTest {

    public static class Employee {
        public String firstName;
        public String lastName;
        public Employee(){}
        public Employee(String firstName, String lastName) {
            this.firstName = firstName;
            this.lastName = lastName;
        }
    }

    public static class Company {
        public String companyId;
        public List<Employee> employees;
        public Company(){}
        public Company(String companyId, List<Employee> employees) {
            this.companyId = companyId;
            this.employees = employees;
        }
    }

    @Path("companies")
    public static class CompanyResource {

        @Context
        private ResourceContext resourceContext;

        @Path("{companyId}/employees")
        public EmployeeResource getEmployees() {
            return resourceContext.getResource(EmployeeResource.class);
        }
    }

    public static class EmployeeResource {

        @PathParam("companyId")
        public String companyId;

        @GET
        @Produces(MediaType.APPLICATION_JSON)
        public Company getCompanyEmployees() {
            List<Employee> emps = new ArrayList<>();
            emps.add(new Employee("pee", "skillet"));
            emps.add(new Employee("Stack", "Overflow"));
            Company co = new Company(companyId, emps);
            return co;
        }
    }

    @Override
    public ResourceConfig configure() {
        return new ResourceConfig(CompanyResource.class);
    }

    @Test
    public void doit() {
        Response response = target("companies/1234/employees").request().get();
        assertEquals(200, response.getStatus());
        Company co = response.readEntity(Company.class);
        assertNotNull(co.companyId);
        assertEquals("1234", co.companyId);
        assertEquals(2, co.employees.size());
        response.close();
    }
}

Answer 4

以下是 JAX-RS 2.0 可能解决方案的总结：

使用构造函数请求范围内的子资源：

@Path("companies")
public class CompanyResource {

    @Path("{idCompany}/employees")
    public EmployeeResource getEmployees(@PathParam("idCompany") String companyId) {
        return new EmployeeResource(companyId);
    }
}  

public class EmployeeResource {

    private String companyId

    public EmployeeResource(String companyId) {
        this.companyId = companyId;
    }

    @GET
    public List<Employee> getEmployees() {
        //some code
    }
}

缺点：

没有依赖注入

请求范围子资源 ResourceContext#initResource(Class):

@Path("companies")
public class CompanyResource {

    @Context
    private ResourceContext resourceContext;

    @GET
    @Path("{idCompany}/employees")
    public EmployeeResource getEmployees(@PathParam("idCompany") String companyId) {
        EmployeeResource employeeResource = new EmployeeResource(companyId);
        return resourceContext.initResource(employeeResource);
    }
}  

public class EmployeeResource {

    @Context
    private Request request;

    private String companyId

    public EmployeeResource(String companyId) {
        this.companyId = companyId;
    }

    @GET
    public List<Employee> getEmployees() {
        //some code
    }
}

缺点：

没有依赖注入 JSR-330

请求范围子资源 ResourceContext#getResource(Class):

@Path("companies")
public class CompanyResource {

    @Context
    private ResourceContext resourceContext;

    @GET
    @Path("{idCompany}/employees")
    public EmployeeResource getEmployees(@PathParam("idCompany") String companyId) {
        EmployeeResource employeeResource = resourceContext.getResource(EmployeeResource.class);
        employeeResource.setCompanyId(companyId);
        return employeeResource;
    }
}  

public class EmployeeResource {

    @Context
    private Request request;

    private String companyId

    public setCompanyId(String companyId) {
        this.companyId = companyId;
    }

    @GET
    public List<Employee> getEmployees() {
        //some code
    }
}

缺点：

没有依赖注入 JSR-330

以@PathParam作为字段请求范围子资源：

@Path("companies")
public class CompanyResource {

    @Context
    private ResourceContext resourceContext;

    @GET
    @Path("{idCompany}/employees")
    public EmployeeResource getEmployees() {
        return resourceContext.getResource(EmployeeResource.class);
    }
}  

public class EmployeeResource {

    @Context
    private Request request;

    @PathParam("idCompany")
    private String companyId;

    @GET
    public List<Employee> getEmployees() {
        // some code
    }
}

缺点：

没有依赖注入 JSR-330

请求 return 类型的子资源 Class<T>:

@Path("companies")
public class CompanyResource {

    @GET
    @Path("{idCompany}/employees")
    public Class<EmployeeResource> getEmployees() {
        return EmployeeResource.class;
    }
}  

public class EmployeeResource {

    @Context
    private Request request;

    @PathParam("idCompany")
    private String companyId;

    @GET
    public List<Employee> getEmployees() {
        // some code
    }
}

缺点：

没有依赖注入 JSR-330

使用@PathParam作为方法参数请求范围子资源：

@Path("companies")
public class CompanyResource {

    @Context
    private ResourceContext resourceContext;

    @GET
    @Path("{idCompany}/employees")
    public Class<EmployeeResource> getEmployees() {
        return resourceContext.getResource(EmployeeResource.class);
    }
}  

public class EmployeeResource {

    @Context
    private Request request;

    @GET
    public List<Employee> getEmployees(@PathParam("idCompany") String companyId) {
        // some code
    }
}

缺点：

没有依赖注入 JSR-330

方法参数为@PathParam的单例子资源：

@Path("companies")
public class CompanyResource {

    @Context
    private ResourceContext resourceContext;

    @GET
    @Path("{idCompany}/employees")
    public Class<EmployeeResource> getEmployees() {
        return resourceContext.getResource(EmployeeResource.class);
    }
}  

@Singleton
public class EmployeeResource {

    @Context
    private Request request;

    @GET
    public List<Employee> getEmployees(@PathParam("idCompany") String companyId) {
        // some code
    }
}

缺点：

没有依赖注入 JSR-330

另请参阅：

将 @PathParam 传递给 Jersey 中的子资源定位器 class

Passing @PathParam to Sub Resource locator class in Jersey

java

rest

jersey