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This means you can use JMX to stop/start routes, and also get the JMX metrics about the routes, such as number of message processed, and their performance statistics.
Example - camel-example-spark-rest-tomcat
We provide an example that uses the REST DSL with the Spark Rest component that can be deployed in web containers such as Apache Tomcat. This example defines a single REST service which offers a GET operation that accepts 3 different types: plain text, json, and xml.
...
Binding to POJOs using
The Rest DSL supports automatic binding json/xml contents to/from POJOs using Camels Data Format. By default the binding mode is off, meaning there is no automatic binding happening for incoming and outgoing messages.
You may want to use binding if you develop POJOs that maps to your REST services request and response types. This allows you as a developer to work with the POJOs in Java code.
The binding modes are:
Binding Mode |
Description |
off |
Binding is turned off. This is the default option. |
auto |
Binding is enabled and Camel is relaxed and support json, xml or both if the needed data formats are included in the classpath. Notice that if for example camel-jaxb is not on the classpath, then XML binding is not enabled. |
json |
Binding to/from json is enabled, and requires a json capabile data format on the classpath. By default Camel will use json-jackson as the data format. |
xml |
Binding to/from xml is enabled, and requires camel-jaxb on the classpath. |
json_xml |
Biding to/from json and xml is enabled and requires both data formats to be on the classpath. |
To use binding you must include the necessary data formats on the classpath, such as camel-jaxb
and/or camel-jackson
. And then enable the binding mode. You can configure the binding mode globally on the rest configuration, and then override per rest service as well.
To enable binding you configure this in Java DSL as shown below
Code Block |
restConfiguration().component("restlet").host("localhost").port(portNum).bindingMode(RestBindingMode.auto);
|
And in XML DSL
Code Block |
<restConfiguration bindingMode="auto" component="restlet" port="8080"/>
|
When binding is enabled Camel will bind the incoming and outgoing messages automatic, accordingly to the content type of the message. If the message is json, then json binding happens; and so if the message is xml then xml binding happens. The binding happens for incoming and reply messages. The table below summaries what binding occurs for incoming and reply messages.
Message Body |
Direction |
Binding Mode |
Message Body |
XML |
Incoming |
auto xml json_xml |
POJO |
POJO |
Outgoing |
auto xml json_xml |
XML |
JSON |
Incoming |
auto json json_xml |
POJO |
POJO |
Outgoing |
auto json json_xml |
JSON |
When using binding you must also configure what POJO type to map to. This is mandatory for incoming messages, and optional for outgoing.
For example to map from xml/json to a pojo class UserPojo
you do this in Java DSL as shown below:
Code Block |
// configure to use restlet on localhost with the given port
// and enable auto binding mode
restConfiguration().component("
|
...
restlet").host("localhost").port(portNum).bindingMode(RestBindingMode.auto);
// use the rest DSL to define the rest services
rest("/
|
...
...
...
...
...
type(UserPojo.class)
.to("
|
...
...
...
Notice we use type
to define the incoming type. We can optionally define an outgoing type (which can be a good idea, to make it known from the DSL and also for tooling and JMX APIs to know both the incoming and outgoing types of the REST services.). To define the outgoing type, we use outType
as shown below:
Code Block |
// configure to use restlet on localhost with the given port
// and enable auto binding mode
restConfiguration().component("restlet").host("localhost").port(portNum).bindingMode(RestBindingMode.auto);
// use the rest DSL to define the rest services
rest("/users/")
.post("new").type(UserPojo.class).outType(CountryPojo.class)
.to("direct:newUser");
|
The UserPojo
is just a plain pojo with getter/setter as shown:
Code Block |
public class UserPojo {
private int id;
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
|
The UserPojo
only supports json, as XML requires to use JAXB annotations, so we can add those annotations if we want to support XML also
Code Block |
@XmlRootElement(name = "user")
@XmlAccessorType(XmlAccessType.FIELD)
public class UserPojo {
@XmlAttribute
private int id;
@XmlAttribute
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
|
By having the JAXB annotations the POJO supports both json and xml bindings.
Configuring Rest DSL
The Rest DSL allows to configure the following options using a builder style
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Option |
Default |
Description |
component |
|
The Camel Rest component to use for the REST transport, such as restlet, spark-rest. If no component has been explicit configured, then Camel will lookup if there is a Camel component that integrates with the Rest DSL, or if a org.apache.camel.spi.RestConsumerFactory is registered in the registry. If either one is found, then that is being used. |
scheme |
http |
The scheme to use for exposing the REST service. Usually http or https is supported |
hostname |
0.0.0.0 |
The hostname to use for exposing the REST service. |
port |
|
The port number to use for exposing the REST service. |
bindingMode |
off |
Whether binding is in use. See further above for more details. |
componentProperty |
|
Allows to configure as many additional properties. This is used to configure component specific options such as for Restlet / Spark-Rest etc. |
endpointProperty |
|
Allows to configure as many additional properties. This is used to configure endpoint specific options for Restlet / Spark-Rest etc. |
consumerProperty |
|
Allows to configure as many additional properties. This is used to configure consumer specific options for Restlet / Spark-Rest etc. |
...