JAX-RS之@QueryParam和@DefaultValue

先来看@queryparam
   先看例子:
 

1.   
2. Path("/users")   
3. public class
4.     
5. @GET
6. @Path("/query")   
7. public
8. @QueryParam("from") int
9. @QueryParam("to") int
10. @QueryParam("orderBy") List<String> orderBy) {   
11.     
12. return
13. 200)   
14. "getUsers is called, from : " + from + ", to : "
15. ", orderBy"
16.     
17.     }   
18.     
19. }

Path("/users")
public class UserService {
 
  @GET
  @Path("/query")
  public Response getUsers(
    @QueryParam("from") int from,
    @QueryParam("to") int to,
    @QueryParam("orderBy") List<String> orderBy) {
 
    return Response
       .status(200)
       .entity("getUsers is called, from : " + from + ", to : " + to
      + ", orderBy" + orderBy.toString()).build();
 
  }
 
}

   URL输入为:users/query?from=100&to=200&orderBy=age&orderBy=name

  此时,输出为:

getUsers is called, from : 100, to : 200, orderBy[age, name]

   要注意的是,跟@pathparam不同,@queryparam

中,指定的是URL中的参数是以键值对的形式出现的,而在程序中

@QueryParam("from") int from则读出URL中from的值,

而@pathparem中,URL中只出现参数的值,不出现键值对,比如:

“/users/2011/06/30”

则:

  ​

1. @GET
2. @Path("{year}/{month}/{day}")   
3. public
4. @PathParam("year") int
5. @PathParam("month") int
6. @PathParam("day") int
7.     
8. "/" + month + "/"
9.     
10. return Response.status(200)   
11. "getUserHistory is called, year/month/day : "
12.         .build();   
13.     
14.     }

@GET
  @Path("{year}/{month}/{day}")
  public Response getUserHistory(
      @PathParam("year") int year,
      @PathParam("month") int month, 
      @PathParam("day") int day) {
 
     String date = year + "/" + month + "/" + day;
 
     return Response.status(200)
    .entity("getUserHistory is called, year/month/day : " + date)
    .build();
 
  }

输出为:

getUserHistory is called, year/month/day : 2011/6/30

2 以动态的方式获得:

1. @Path("/users")   
2. public class
3.     
4. @GET
5. @Path("/query")   
6. public Response getUsers(@Context
7.     
8. "from");   
9. "to");   
10. "orderBy");   
11.     
12. return
13. 200)   
14. "getUsers is called, from : " + from + ", to : "
15. ", orderBy"
16.     
17.     }   
18.

@Path("/users")
public class UserService {
 
  @GET
  @Path("/query")
  public Response getUsers(@Context UriInfo info) {
 
    String from = info.getQueryParameters().getFirst("from");
    String to = info.getQueryParameters().getFirst("to");
    List<String> orderBy = info.getQueryParameters().get("orderBy");
 
    return Response
       .status(200)
       .entity("getUsers is called, from : " + from + ", to : " + to
      + ", orderBy" + orderBy.toString()).build();
 
  }

URL;users/query?from=100&to=200&orderBy=age&orderBy=name

输出为:

getUsers is called, from : 100, to : 200, orderBy[age, name]

注意这里把orderby后的两个参数读入为LIST处理了.

3 @DefaultValue,默认值

  例子:

Java代码 
1. @Path("/users")   
2. public class
3.     
4. @GET
5. @Path("/query")   
6. public
7. @DefaultValue("1000") @QueryParam("from") int
8. @DefaultValue("999")@QueryParam("to") int
9. @DefaultValue("name") @QueryParam("orderBy") List<String> orderBy) {   
10.     
11. return
12. 200)   
13. "getUsers is called, from : " + from + ", to : "
14. ", orderBy"
15.     
16.     }

@Path("/users")
public class UserService {
 
  @GET
  @Path("/query")
  public Response getUsers(
    @DefaultValue("1000") @QueryParam("from") int from,
    @DefaultValue("999")@QueryParam("to") int to,
    @DefaultValue("name") @QueryParam("orderBy") List<String> orderBy) {
 
    return Response
       .status(200)
       .entity("getUsers is called, from : " + from + ", to : " + to
      + ", orderBy" + orderBy.toString()).build();
 
  }

URL:users/query

输出:getUsers is called, from : 1000, to : 999, orderBy[name]

很好理解吧