In this pattern, the web service declares the URI for the newly created resource. Entity providers supply mapping services between representations and their associated Java types. If the application needs to supply additional metadata, such as HTTP headers or a different status code, a method can return a Response that wraps the entity and that can be built by using Response.
Table 13—3 shows the standard types that are supported automatically for entities. You need to write an entity provider only if you are not choosing one of these standard types.
The following example shows how to use MessageBodyReader with the Consumes and Provider annotations:. The following example shows how to use MessageBodyWriter with the Produces and Provider annotations:. You can specify which MIME media types of representations a resource can respond to or produce by using the following annotations:.
The Produces annotation is used to specify the MIME media types or representations a resource can produce and send back to the client. If Produces is applied at the class level, all the methods in a resource can produce the specified MIME types by default.
If applied at the method level, the annotation overrides any Produces annotations applied at the class level. The following example shows how to apply Produces at both the class and method levels:. If a resource class is capable of producing more than one MIME media type, the resource method chosen will correspond to the most acceptable media type as declared by the client.
More than one media type may be declared in the same Produces declaration. The following code example shows how this is done:.
If both are equally acceptable, the former will be chosen because it occurs first. The preceding examples refer explicitly to MIME media types for clarity. It is possible to refer to constant values, which may reduce typographical errors. The Consumes annotation is used to specify which MIME media types of representations a resource can accept, or consume, from the client. If Consumes is applied at the class level, all the response methods accept the specified MIME types by default.
If applied at the method level, Consumes overrides any Consumes annotations applied at the class level. For example:. The following example shows how to apply Consumes at both the class and method levels:. The doPost2 method overrides the class level Consumes annotation to specify that it can accept URL-encoded form data.
The HelloWorld example discussed previously in this section can be modified to set the message by using Consumes , as shown in the following code example:. Note that the resource method returns void.
Parameters of a resource method may be annotated with parameter-based annotations to extract information from a request. A previous example presented the use of the PathParam parameter to extract a path parameter from the path component of the request URL that matched the path declared in Path.
Query parameters are extracted from the request URI query parameters and are specified by using the javax. QueryParam annotation in the method parameter arguments. The following example, from the sparklines sample application, demonstrates using QueryParam to extract query parameters from the Query component of the request URL:.
If the query parameter step exists in the query component of the request URI, the value of step will be extracted and parsed as a bit signed integer and assigned to the step method parameter.
If step does not exist, a default value of 2, as declared in the DefaultValue annotation, will be assigned to the step method parameter. User-defined Java programming language types may be used as query parameters. The following code example shows the ColorParam class used in the preceding query parameter example:. Any class with the static method named valueOf String that accepts a single String argument.
Sometimes, parameters may contain more than one value for the same name. If this is the case, these types may be used to obtain all values.
If DefaultValue is not used in conjunction with QueryParam , and the query parameter is not present in the request, the value will be an empty collection for List , Set , or SortedSet ; null for other object types; and the default for primitive types. URI parameters are specified using the javax.
PathParam annotation in the method parameter arguments. The following example shows how to use Path variables and the PathParam annotation in a method:. In the preceding snippet, the URI path template variable name username is specified as a parameter to the printUsername method. The PathParam annotation is set to the variable name username.
At runtime, before printUsername is called, the value of username is extracted from the URI and cast to a String. The resulting String is then available to the method as the userId variable.
Cookie parameters , indicated by decorating the parameter with javax. Header parameters , indicated by decorating the parameter with javax. Matrix parameters , indicated by decorating the parameter with javax. MatrixParam , extract information from URL path segments.
Form parameters , indicated by decorating the parameter with javax. The following example extracts the name form parameter from the POST form data:. To obtain a general map of parameter names and values for query and path parameters, use the following code:.
In general, Context can be used to obtain contextual Java types related to the request or response. This section provides an introduction to creating, deploying, and running your own JAX-RS applications.
This section demonstrates the steps that are needed to create, build, deploy, and test a very simple web application that uses JAX-RS annotations. NetBeans IDE generates a skeleton for the application, and you simply need to implement the appropriate methods.
If you do not use an IDE, try using one of the example applications that ship with Jersey as a template to modify. The remaining steps would be the same. Type helloworld in the Path field. Type HelloWorld in the Class Name field. A new resource, HelloWorld. This file provides a template for creating a RESTful web service. In HelloWorld. Test the web service. When the test client appears, select the helloworld resource in the left pane, and click the Test button in the right pane. This tutorial includes a section on creating a CRUD application from a database.
Create, read, update, and delete CRUD are the four basic functions of persistent storage and relational databases. The three enterprise beans in the rsvp example application are rsvp. ConfigBean , rsvp. StatusBean , and rsvp. The URI path template is declared as follows:. The eventId variable is used to look up all the current responses in the database for that particular event.
Each invitee to that event has a unique ID for the invitation, and that is the inviteId. An invitee who wants to change his or her response selects the new response and submits the form data, which is processed as an HTTP PUT request by the putResponse method.
One of the parameters to the putResponse method, the userResponse string, is annotated with FormParam "attendeeResponse". The putResponse method uses userResponse , eventId , and inviteId to update the invitee's response in the database.
The rsvp. Event , rsvp. Person , and rsvp. Response entities respectively represent events, invitees, and responses to an event.
ResponseEnum class declares an enumerated type that represents all the possible response statuses an invitee may have. The project will be compiled, assembled, and deployed to GlassFish Server. Click on the name of one of the invitees, select a response, and click Submit response; then click Back to event page. Click on the name of one of the invitees, select a response, and click Submit response, then click Back to event page. Most blog sites use RESTful web services.
The following principles encourage RESTful applications to be simple, lightweight, and fast: Resource identification through URI : A RESTful web service exposes a set of resources that identify the targets of the interaction with its clients. PathParam The PathParam annotation is a type of parameter that you can extract for use in your resource class. QueryParam The QueryParam annotation is a type of parameter that you can extract for use in your resource class.
Utility function to find maximum sum between any. Base Case. Find maximumsum in left and right subtree. If both left and right children exist. Return maximum possible value for root being.
If any of the two children is empty, return. The main function which returns sum of the maximum. THis function mainly. Driver program to test above function. Next Find the maximum sum leaf to root path in a Binary Tree. Recommended Articles. Tree with N nodes and K leaves such that distance between farthest leaves is minimized. Maximum weighted edge in path between two nodes in an N-ary tree using binary lifting.
Minimum and maximum node that lies in the path connecting two nodes in a Binary Tree. Minimum number of leaves required to be removed from a Tree to satisfy the given condition. Construct a Tree whose sum of nodes of all the root to leaf path is not divisible by the count of nodes in that path.
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