Jax rs what is

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. Ask Question. Asked 10 years, 9 months ago. Active 8 years, 6 months ago. Viewed 25k times.

Could someone provide me some insights about it? Many thanks!!! See also stackoverflow. Add a comment. Active Oldest Votes. Heiko Rupp Heiko Rupp Thank you very much!! I have added some further illustrations of my question in another post, would you please have a look at it? Got it!! Thank you! Arjan Tijms Robby Pond Robby Pond Yes, exactly! I understand they are implementations, but i can't understand the meaning of "being implementations of JAX-RS".

See, I have created a simple rest class and imported namespaces such as "javax. GET", "javax. Path", "javax. Using the Embedded Enterprise Bean Container. Getting Started Securing Web Applications. Getting Started Securing Enterprise Applications. If you are developing with GlassFish Server, you can install the Jersey samples and documentation by using the Update Tool.

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