这几天做东西接触了JAX-RS的东西，没有系统的从开始就学，只是单纯去复制粘贴的用，主要用到了几个Annotations变量，具体如下：
queryparam、PathParam、FormParam、Context、RestController。下面就分别解释下他们的用法：
1.@queryparam
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();
}
}
这里，在url中输入"/users/query/from=1&to=100&orderBy=name&orderBy=age"，则输出一下结果：
getUsers is called, from : 1, to : 100, orderBy[name, age]
这里，也可以以动态方式获得，如下：
@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.
2.@pathParam
与@queryParam类似，但是，queryparam在url中是用键值对来传递，而在pathParam中是只出现值而不出现参数，
url如是："/users/2011/20/10"，例如：
@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(); }
这里通过上面的url将输出：
getUserHistory is called, year/month/day : 2011/20/10
可以用多个param，并且若path中有相同参数名，则采用最接近的参数名所对应的值，如
@Path("/customers/{id}")
public class CustomerResource {
@Path("/address/{id}")
@Produces("text/plain")
@GET
public String getAddress(@PathParam("id") String addressId) {...}
}
如：customers/123/address/456 , 则 addressId 的值为456.
3.@DefaultValue
@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();
}
输入url为：/users/query
输出为：
getUsers is called, from : 1000, to : 999, orderBy[name]
4.@FormParam
FormParam用于提取post请求中的form数据，具体举例如下：
<FORM action="http://example.com/customers" method="post"> <P> First name: <INPUT type="text" name="firstname"><BR> Last name: <INPUT type="text" name="lastname"><BR> <INPUT type="submit" value="Send"> </P> </FORM>
@Path("/customers")
public class CustomerResource {
@POST
public void createCustomer(@FormParam("firstname") String first,
@FormParam("lastname") String last) {
...
}
}
5.@context
当jax-rs服务基于servlet发布的时候 ，还可以通过@Context注入servlet中的ServletConfig , ServletContext ,HttpServletRequest , HttpServletResponse
然后REST就可以通过sessionid来保持住用户状态。举例如下：
@Path("UserContext")
public class UserContext {
@Context UriInfo uriInfo;
@Context HttpHeaders httpHeaders;
@Context SecurityContext sc;
@Context Request req;
@Context Response resp;
@Context HttpServletResponse response;
@Context HttpServletRequest request;
@GET
public String hi(@QueryParam("name") String yourName ){
if(yourName!=null)
request.getSession().setAttribute("name", yourName);
String username = (String) request.getSession().getAttribute("name");
if(username!=null){
System.out.println(request.getSession().getId() + ":" + username);
}
else{
System.out.println(request.getSession().getId() + "没有用户");
}
return null;
}
}
<!--在web.xml加入--> <servlet> <display-name>JAX-RS REST Servlet</display-name> <servlet-name>JAX-RS REST Servlet</servlet-name> <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>JAX-RS REST Servlet</servlet-name> <url-pattern>/services/*</url-pattern> </servlet-mapping>
在url中输入：”/rest/services/UserContext“则输出：
A46756539D2E39CC2CFFCB3FE1C99E70没有用户
若在url中输入：http://localhost:8080/rest/services/UserContext?name=hello
则输出：
A46756539D2E39CC2CFFCB3FE1C99E70:hello
6.@RestController
它继承自@Controller注解，我们可以开发REST服务的时候不需要使用@Controller而专门的@RestController
定义如下：
@Target(value=TYPE) @Retention(value=RUNTIME) @Documented @Controller @ResponseBody public @interface RestController
7.还有cookieparam和headerparam等，此处没怎么接触，就先不学习了。