java - 将@PathParam 传递给 Jersey 中的子资源定位器类

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。我有以下代码:

@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？有没有更正确的方法来做到这一点？

Answer 1

这里总结了 JAX-RS 2.0 可能的解决方案:

• 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(inject)

• 使用 ResourceContext#initResource(Class) 请求范围内的子资源:

  @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(inject) JSR-330

• 使用 ResourceContext#getResource(Class) 请求范围内的子资源:

  @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(inject) JSR-330

• 使用 @PathParam 请求范围内的子资源作为字段:

  @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(inject) JSR-330

• 请求范围内的子资源，返回类型为 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(inject) JSR-330

• 使用 @PathParam 请求范围内的子资源作为方法参数:

  @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(inject) JSR-330

• 带有 @PathParam 的单例子资源作为方法参数:

  @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(inject) JSR-330

另见:

• Jersey User Guide - Rules of Injection
• Jersey User Guide - sub-resources
• Java EE 7 and JAX-RS 2.0
• JAX_RS_SPEC-55