Apache Camel：发布请求正文时出现问题
Apache Camel: Problem POSTing request body
我有一个服务器和客户端应用程序，它们都使用 Apache Camel 来配置和管理它们的路由。我正在尝试使用 REST 组件从客户端向服务器发出 POST 请求，并在请求正文中发送消息。似乎正在调用 REST 端点，但正文没有通过。我想我要么遗漏了一些步骤，要么我做错了。
另一件要提及的事情是，我使用的是通用消息 class，它基本上可以包含任何对象（包括字节或字符数组）。也许这是我遇到的问题背后的部分（或全部）原因。
GenericMessage.java:
public class GenericMessage<T extends Object> {
private T payload;
public GenericMessage(T payload) {
this.payload = payload;
}
public T getPayload() {
return payload;
}
public void setPayload(T payload) {
this.payload = payload;
}
@Override
public String toString() {
return "GenericMessage [payload=" + payload + "]";
}
}
服务器
驼色-context.xml:
<camelContext id="camel-context" xmlns="http://camel.apache.org/schema/spring">
<restConfiguration component="jetty" bindingMode="json"
contextPath="/" host="localhost" port="9100">
<dataFormatProperty key="prettyPrint" value="true" />
</restConfiguration>
<rest>
<get uri="/data?size={size}" produces="JSON">
<route id="get-data-by-size">
<log loggingLevel="INFO" message="start - get-data-by-size" />
<process ref="get-request-processor" />
<log loggingLevel="INFO" message="end - get-data-by-size" />
</route>
</get>
<post uri="post-data" consumes="json">
<route id="post-data">
<log loggingLevel="INFO" message="start - post-data" />
<process ref="post-request-processor" />
<log loggingLevel="INFO" message="end - post-data" />
</route>
</post>
</rest>
</camelContext>
GetRequestProcessor.java:
@Component("get-request-processor")
public class GetRequestProcessor implements Processor {
@Autowired
private DataProvider provider;
public void process(Exchange exchange) throws Exception {
int size = exchange.getIn().getHeader("size", Integer.class);
// TODO currently only sends char[] data
GenericMessage<?> data = provider.getCharData(size);
exchange.getMessage().setBody(data, GenericMessage.class);
}
}
PostRequestProcessor.java:
@Component("post-request-processor")
public class PostRequestProcessor implements Processor {
private final Logger logger = LoggerFactory.getLogger(PostRequestProcessor.class);
public void process(Exchange exchange) throws Exception {
GenericMessage<?> data = exchange.getIn().getBody(GenericMessage.class);
if (data != null) {
logger.info("process: object received: {}", data);
} else {
logger.warn("process: null object");
}
}
}
DataProvider.java:
@Component
public class DataProvider {
private final Logger logger = LoggerFactory.getLogger(DataProvider.class);
public GenericMessage<?> getByteData(final int size) {
logger.info("getByteData: size={}", size);
return new GenericMessage<byte[]>(DataGenerator.generateByteArray(size));
}
public GenericMessage<?> getCharData(final int size) {
logger.info("getCharData: size={}", size);
return new GenericMessage<char[]>(DataGenerator.generateCharArray(size));
}
}
客户
驼色-context.xml:
<camelContext id="camel-context" xmlns="http://camel.apache.org/schema/spring">
<restConfiguration component="jetty" bindingMode="json"
contextPath="/" host="{{http-client.server.host}}"
port="{{http-client.server.port}}">
<dataFormatProperty key="prettyPrint" value="true" />
</restConfiguration>
<route id="rest-get">
<from
uri="timer:{{http-client.timers.http-get.name}}?delay={{http-client.timers.http-get.start-delay}}&fixedRate=true&period={{http-client.timers.http-get.period}}&repeatCount={{http-client.timers.http-get.repeat-count}}" />
<log loggingLevel="INFO" message="start - rest-get" />
<to uri="rest:get:{{http-client.endpoints.http-get}}" />
<process ref="process-get-response" />
<log loggingLevel="INFO" message="end - rest-get" />
</route>
<route id="rest-post">
<from
uri="timer:{{http-client.timers.http-post.name}}?delay={{http-client.timers.http-post.start-delay}}&fixedRate=true&period={{http-client.timers.http-post.period}}&repeatCount={{http-client.timers.http-post.repeat-count}}" />
<log loggingLevel="INFO" message="start - rest-post" />
<process ref="add-post-body" />
<to uri="rest:post:{{http-client.endpoints.http-post}}" />
<log loggingLevel="INFO" message="end - rest-post" />
</route>
</camelContext>
AddPostRequestBody.java:
@Component("add-post-body")
public class AddPostRequestBody implements Processor {
private final Logger logger = LoggerFactory.getLogger(AddPostRequestBody.class);
@Autowired
private DataProvider provider;
@Override
public void process(Exchange exchange) throws Exception {
GenericMessage<?> data = null;
int intValue = RandomUtil.generateInt(1);
switch (intValue) {
case 0:
data = provider.produceByteArrayData();
break;
case 1:
data = provider.produceCharArrayData();
break;
default:
break;
}
logger.info("adding POST request body:\n{}", data);
exchange.getMessage().setHeader(Exchange.HTTP_METHOD, "POST");
exchange.getMessage().setHeader(Exchange.CONTENT_TYPE, "application/json");
exchange.getMessage().setBody(data, GenericMessage.class);
}
}
GetResponseProcessor.java:
@Component("process-get-response")
public class GetResponseProcessor implements Processor {
private final Logger logger = LoggerFactory.getLogger(GetResponseProcessor.class);
@Override
public void process(Exchange exchange) throws Exception {
GenericMessage<?> body = (GenericMessage<?>) exchange.getIn().getBody();
logger.info("body: {}", body);
}
}
DataProvider.java:
@Component
public class DataProvider {
private final Logger logger = LoggerFactory.getLogger(DataProvider.class);
public GenericMessage<byte[]> produceByteArrayData() {
int size = RandomUtil.generateInt(1000, 20000000);
byte[] bytes = DataGenerator.generateByteArray(size);
logger.info("produceByteArrayData: generated {} bytes", size);
GenericMessage<byte[]> data = new GenericMessage<>(bytes);
return data;
}
public GenericMessage<char[]> produceCharArrayData() {
int size = RandomUtil.generateInt(1000, 20000000);
char[] chars = DataGenerator.generateCharArray(size);
logger.info("produceCharArrayData: generated {} characters", size);
GenericMessage<char[]> data = new GenericMessage<>(chars);
return data;
}
}
我已将其配置为执行来自客户端的一个 POST 请求。散布着日志记录语句，以了解发生了什么。
客户端控制台：
2020-04-13 13:23:39.805 INFO 17464 --- [ main] o.a.c.i.e.AbstractCamelContext : Route: rest-get started and consuming from: timer://http-get
2020-04-13 13:23:39.806 INFO 17464 --- [ main] o.a.c.i.e.AbstractCamelContext : Route: rest-post started and consuming from: timer://http-post
2020-04-13 13:23:39.812 INFO 17464 --- [ main] o.a.c.i.e.AbstractCamelContext : Total 2 routes, of which 2 are started
2020-04-13 13:23:39.812 INFO 17464 --- [ main] o.a.c.i.e.AbstractCamelContext : Apache Camel 3.1.0 (CamelContext: RESTClient) started in 1.679 seconds
2020-04-13 13:23:42.308 INFO 17464 --- [mer://http-post] rest-post : start - rest-post
2020-04-13 13:23:42.312 INFO 17464 --- [mer://http-post] e.m.l.m.s.DataProvider : produceCharArrayData: generated 1039 characters
2020-04-13 13:23:42.313 INFO 17464 --- [mer://http-post] e.m.l.m.p.AddPostRequestBody : CLIENT: Adding POST request body:
GenericMessage [payload=[C@2124c204]
2020-04-13 13:23:42.408 INFO 17464 --- [mer://http-post] rest-post : end - rest-post
服务器控制台：
2020-04-13 13:23:10.846 INFO 23260 --- [ main] o.a.c.i.e.AbstractCamelContext : Route: get-data-by-size started and consuming from: jetty:http://localhost:9100/data
2020-04-13 13:23:10.847 INFO 23260 --- [ main] o.a.c.i.e.AbstractCamelContext : Route: post-data started and consuming from: jetty:http://localhost:9100/post-data
2020-04-13 13:23:10.852 INFO 23260 --- [ main] o.a.c.i.e.AbstractCamelContext : Total 2 routes, of which 2 are started
2020-04-13 13:23:10.853 INFO 23260 --- [ main] o.a.c.i.e.AbstractCamelContext : Apache Camel 3.1.0 (CamelContext: RESTServer) started in 0.314 seconds
2020-04-13 13:23:42.395 INFO 23260 --- [tp1276761134-37] post-data : start - post-data
2020-04-13 13:23:42.396 INFO 23260 --- [tp1276761134-37] e.m.l.m.p.PostRequestProcessor : SERVER: Processing POST request
2020-04-13 13:23:42.400 WARN 23260 --- [tp1276761134-37] e.m.l.m.p.PostRequestProcessor : null object
2020-04-13 13:23:42.400 INFO 23260 --- [tp1276761134-37] post-data : end - post-data
Camel 不认识你的 GenericMessage class，所以它不知道如何转换 to/from 它。
Camel 使用可插入的 type converters 来告诉它如何在不同类型的对象之间转换消息（正文）。
内置类型转换器涵盖了很多常见情况（例如，字符串到整数、迭代器到 ArrayList 等），但它们不知道如何与任何自定义类型相互转换 classes你写。
这就是为什么服务器处理器中的这一行 returns null:
GenericMessage<?> data = exchange.getIn().getBody(GenericMessage.class);
因为当时 Body 是 Stream，但 Camel 不知道如何将其转换为您要求的 GenericMessage。
（如果您希望抛出异常，则 getBody(Class<T>) is to return null if it can't convert. Try using getMandatoryBody(Class<T>) 的默认行为。）
在客户端：如何获得 GenericMessage 的响应？您需要使用 unmarshalling。您首先将 JSON 解组为 Java 对象。正是在这一点上，您需要向 Camel 提示要解组到哪个 class。
<dataFormats>
<json id="myGeneric" .... unmarshalTypeName="....GenericMessage"/>
</dataFormats>
...
<unmarshal><custom ref="myGeneric"/></unmarshal>
然后 Body 将是您的 GenericMessage 类型。
请注意，在 Camel 中，类型转换和 marshalling/unmarshalling 是两个不同的东西。
在服务器端： Camel 将尝试将来自 JSON 的请求解组为简单的 Java 对象（例如 HashMap 等）自动地。要告诉它解组为特定的 POJO，请在 REST 动词定义上设置 type，例如：
<post uri="post-data" consumes="json" type="com.example.demo.GenericMessage">
您也可以使用相同的方法来定义 outType（用于将响应编组回 JSON）
我有一个服务器和客户端应用程序，它们都使用 Apache Camel 来配置和管理它们的路由。我正在尝试使用 REST 组件从客户端向服务器发出 POST 请求，并在请求正文中发送消息。似乎正在调用 REST 端点，但正文没有通过。我想我要么遗漏了一些步骤，要么我做错了。
另一件要提及的事情是，我使用的是通用消息 class，它基本上可以包含任何对象（包括字节或字符数组）。也许这是我遇到的问题背后的部分（或全部）原因。
GenericMessage.java:
public class GenericMessage<T extends Object> {
private T payload;
public GenericMessage(T payload) {
this.payload = payload;
}
public T getPayload() {
return payload;
}
public void setPayload(T payload) {
this.payload = payload;
}
@Override
public String toString() {
return "GenericMessage [payload=" + payload + "]";
}
}
服务器
驼色-context.xml:
<camelContext id="camel-context" xmlns="http://camel.apache.org/schema/spring">
<restConfiguration component="jetty" bindingMode="json"
contextPath="/" host="localhost" port="9100">
<dataFormatProperty key="prettyPrint" value="true" />
</restConfiguration>
<rest>
<get uri="/data?size={size}" produces="JSON">
<route id="get-data-by-size">
<log loggingLevel="INFO" message="start - get-data-by-size" />
<process ref="get-request-processor" />
<log loggingLevel="INFO" message="end - get-data-by-size" />
</route>
</get>
<post uri="post-data" consumes="json">
<route id="post-data">
<log loggingLevel="INFO" message="start - post-data" />
<process ref="post-request-processor" />
<log loggingLevel="INFO" message="end - post-data" />
</route>
</post>
</rest>
</camelContext>
GetRequestProcessor.java:
@Component("get-request-processor")
public class GetRequestProcessor implements Processor {
@Autowired
private DataProvider provider;
public void process(Exchange exchange) throws Exception {
int size = exchange.getIn().getHeader("size", Integer.class);
// TODO currently only sends char[] data
GenericMessage<?> data = provider.getCharData(size);
exchange.getMessage().setBody(data, GenericMessage.class);
}
}
PostRequestProcessor.java:
@Component("post-request-processor")
public class PostRequestProcessor implements Processor {
private final Logger logger = LoggerFactory.getLogger(PostRequestProcessor.class);
public void process(Exchange exchange) throws Exception {
GenericMessage<?> data = exchange.getIn().getBody(GenericMessage.class);
if (data != null) {
logger.info("process: object received: {}", data);
} else {
logger.warn("process: null object");
}
}
}
DataProvider.java:
@Component
public class DataProvider {
private final Logger logger = LoggerFactory.getLogger(DataProvider.class);
public GenericMessage<?> getByteData(final int size) {
logger.info("getByteData: size={}", size);
return new GenericMessage<byte[]>(DataGenerator.generateByteArray(size));
}
public GenericMessage<?> getCharData(final int size) {
logger.info("getCharData: size={}", size);
return new GenericMessage<char[]>(DataGenerator.generateCharArray(size));
}
}
客户
驼色-context.xml:
<camelContext id="camel-context" xmlns="http://camel.apache.org/schema/spring">
<restConfiguration component="jetty" bindingMode="json"
contextPath="/" host="{{http-client.server.host}}"
port="{{http-client.server.port}}">
<dataFormatProperty key="prettyPrint" value="true" />
</restConfiguration>
<route id="rest-get">
<from
uri="timer:{{http-client.timers.http-get.name}}?delay={{http-client.timers.http-get.start-delay}}&fixedRate=true&period={{http-client.timers.http-get.period}}&repeatCount={{http-client.timers.http-get.repeat-count}}" />
<log loggingLevel="INFO" message="start - rest-get" />
<to uri="rest:get:{{http-client.endpoints.http-get}}" />
<process ref="process-get-response" />
<log loggingLevel="INFO" message="end - rest-get" />
</route>
<route id="rest-post">
<from
uri="timer:{{http-client.timers.http-post.name}}?delay={{http-client.timers.http-post.start-delay}}&fixedRate=true&period={{http-client.timers.http-post.period}}&repeatCount={{http-client.timers.http-post.repeat-count}}" />
<log loggingLevel="INFO" message="start - rest-post" />
<process ref="add-post-body" />
<to uri="rest:post:{{http-client.endpoints.http-post}}" />
<log loggingLevel="INFO" message="end - rest-post" />
</route>
</camelContext>
AddPostRequestBody.java:
@Component("add-post-body")
public class AddPostRequestBody implements Processor {
private final Logger logger = LoggerFactory.getLogger(AddPostRequestBody.class);
@Autowired
private DataProvider provider;
@Override
public void process(Exchange exchange) throws Exception {
GenericMessage<?> data = null;
int intValue = RandomUtil.generateInt(1);
switch (intValue) {
case 0:
data = provider.produceByteArrayData();
break;
case 1:
data = provider.produceCharArrayData();
break;
default:
break;
}
logger.info("adding POST request body:\n{}", data);
exchange.getMessage().setHeader(Exchange.HTTP_METHOD, "POST");
exchange.getMessage().setHeader(Exchange.CONTENT_TYPE, "application/json");
exchange.getMessage().setBody(data, GenericMessage.class);
}
}
GetResponseProcessor.java:
@Component("process-get-response")
public class GetResponseProcessor implements Processor {
private final Logger logger = LoggerFactory.getLogger(GetResponseProcessor.class);
@Override
public void process(Exchange exchange) throws Exception {
GenericMessage<?> body = (GenericMessage<?>) exchange.getIn().getBody();
logger.info("body: {}", body);
}
}
DataProvider.java:
@Component
public class DataProvider {
private final Logger logger = LoggerFactory.getLogger(DataProvider.class);
public GenericMessage<byte[]> produceByteArrayData() {
int size = RandomUtil.generateInt(1000, 20000000);
byte[] bytes = DataGenerator.generateByteArray(size);
logger.info("produceByteArrayData: generated {} bytes", size);
GenericMessage<byte[]> data = new GenericMessage<>(bytes);
return data;
}
public GenericMessage<char[]> produceCharArrayData() {
int size = RandomUtil.generateInt(1000, 20000000);
char[] chars = DataGenerator.generateCharArray(size);
logger.info("produceCharArrayData: generated {} characters", size);
GenericMessage<char[]> data = new GenericMessage<>(chars);
return data;
}
}
我已将其配置为执行来自客户端的一个 POST 请求。散布着日志记录语句，以了解发生了什么。
客户端控制台：
2020-04-13 13:23:39.805 INFO 17464 --- [ main] o.a.c.i.e.AbstractCamelContext : Route: rest-get started and consuming from: timer://http-get
2020-04-13 13:23:39.806 INFO 17464 --- [ main] o.a.c.i.e.AbstractCamelContext : Route: rest-post started and consuming from: timer://http-post
2020-04-13 13:23:39.812 INFO 17464 --- [ main] o.a.c.i.e.AbstractCamelContext : Total 2 routes, of which 2 are started
2020-04-13 13:23:39.812 INFO 17464 --- [ main] o.a.c.i.e.AbstractCamelContext : Apache Camel 3.1.0 (CamelContext: RESTClient) started in 1.679 seconds
2020-04-13 13:23:42.308 INFO 17464 --- [mer://http-post] rest-post : start - rest-post
2020-04-13 13:23:42.312 INFO 17464 --- [mer://http-post] e.m.l.m.s.DataProvider : produceCharArrayData: generated 1039 characters
2020-04-13 13:23:42.313 INFO 17464 --- [mer://http-post] e.m.l.m.p.AddPostRequestBody : CLIENT: Adding POST request body:
GenericMessage [payload=[C@2124c204]
2020-04-13 13:23:42.408 INFO 17464 --- [mer://http-post] rest-post : end - rest-post
服务器控制台：
2020-04-13 13:23:10.846 INFO 23260 --- [ main] o.a.c.i.e.AbstractCamelContext : Route: get-data-by-size started and consuming from: jetty:http://localhost:9100/data
2020-04-13 13:23:10.847 INFO 23260 --- [ main] o.a.c.i.e.AbstractCamelContext : Route: post-data started and consuming from: jetty:http://localhost:9100/post-data
2020-04-13 13:23:10.852 INFO 23260 --- [ main] o.a.c.i.e.AbstractCamelContext : Total 2 routes, of which 2 are started
2020-04-13 13:23:10.853 INFO 23260 --- [ main] o.a.c.i.e.AbstractCamelContext : Apache Camel 3.1.0 (CamelContext: RESTServer) started in 0.314 seconds
2020-04-13 13:23:42.395 INFO 23260 --- [tp1276761134-37] post-data : start - post-data
2020-04-13 13:23:42.396 INFO 23260 --- [tp1276761134-37] e.m.l.m.p.PostRequestProcessor : SERVER: Processing POST request
2020-04-13 13:23:42.400 WARN 23260 --- [tp1276761134-37] e.m.l.m.p.PostRequestProcessor : null object
2020-04-13 13:23:42.400 INFO 23260 --- [tp1276761134-37] post-data : end - post-data
Camel 不认识你的 GenericMessage class，所以它不知道如何转换 to/from 它。
Camel 使用可插入的 type converters 来告诉它如何在不同类型的对象之间转换消息（正文）。
内置类型转换器涵盖了很多常见情况（例如，字符串到整数、迭代器到 ArrayList 等），但它们不知道如何与任何自定义类型相互转换 classes你写。
这就是为什么服务器处理器中的这一行 returns null:
GenericMessage<?> data = exchange.getIn().getBody(GenericMessage.class);
因为当时 Body 是 Stream，但 Camel 不知道如何将其转换为您要求的 GenericMessage。
（如果您希望抛出异常，则 getBody(Class<T>) is to return null if it can't convert. Try using getMandatoryBody(Class<T>) 的默认行为。）
在客户端：如何获得 GenericMessage 的响应？您需要使用 unmarshalling。您首先将 JSON 解组为 Java 对象。正是在这一点上，您需要向 Camel 提示要解组到哪个 class。
<dataFormats>
<json id="myGeneric" .... unmarshalTypeName="....GenericMessage"/>
</dataFormats>
...
<unmarshal><custom ref="myGeneric"/></unmarshal>
然后 Body 将是您的 GenericMessage 类型。
请注意，在 Camel 中，类型转换和 marshalling/unmarshalling 是两个不同的东西。
在服务器端： Camel 将尝试将来自 JSON 的请求解组为简单的 Java 对象（例如 HashMap 等）自动地。要告诉它解组为特定的 POJO，请在 REST 动词定义上设置 type，例如：
<post uri="post-data" consumes="json" type="com.example.demo.GenericMessage">
您也可以使用相同的方法来定义 outType（用于将响应编组回 JSON）