WebService @QueryParam @DefaultValue @PathParam的区别

1 先来看@queryparam
   先看例子:
 
Java代码

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:
 
Java代码

@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:
 
Java代码

@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

@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