Red Hat Summit 红帽全球峰会支持控制台（Console）开发人员开始试用联系人

此内容没有您所选择的语言版本。

59.6. Entity Reader Interceptor

Overview
复制链接

This section explains how to implement and register an entity reader interceptor, which enables you to intercept the input stream when reading a message body either on the client side or on the server side. This is typically useful for generic transformations of the request body, such as encryption and decryption, or compressing and decompressing.

ReaderInterceptor interface
复制链接

The javax.ws.rs.ext.ReaderInterceptor interface is defined as follows: 
// Java
...
package javax.ws.rs.ext;

public interface ReaderInterceptor {
    public Object aroundReadFrom(ReaderInterceptorContext context)
            throws java.io.IOException, javax.ws.rs.WebApplicationException;
}
Copy to Clipboard Toggle word wrap
By implementing the ReaderInterceptor interface, you can intercept the message body (Entity object) as it is being read either on the server side or the client side. You can use an entity reader interceptor in either of the following contexts:
  • Server side—if bound as a server-side interceptor, the entity reader interceptor intercepts the request message body when it is accessed by the application code (in the matched resource). Depending on the semantics of the REST request, the message body might not be accessed by the matched resource, in which case the reader interceptor is not called.
  • Client side—if bound as a client-side interceptor, the entity reader interceptor intercepts the response message body when it is accessed by the client code. If the client code does not explicitly access the response message (for example, by calling the Response.getEntity method), the reader interceptor is not called.

ReaderInterceptorContext interface
复制链接

The aroundReadFrom method of ReaderInterceptor receives one argument of type javax.ws.rs.ext.ReaderInterceptorContext, which can be used to access both the message body (Entity object) and message metadata.
The ReaderInterceptorContext interface is defined as follows: 
// Java
...
package javax.ws.rs.ext;

import java.io.IOException;
import java.io.InputStream;

import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MultivaluedMap;

public interface ReaderInterceptorContext extends InterceptorContext {

    public Object proceed() throws IOException, WebApplicationException;

    public InputStream getInputStream();

    public void setInputStream(InputStream is);

    public MultivaluedMap<String, String> getHeaders();
}
Copy to Clipboard Toggle word wrap

InterceptorContext interface
复制链接

The ReaderInterceptorContext interface also supports the methods inherited from the base InterceptorContext interface.
The InterceptorContext interface is defined as follows: 
// Java
...
package javax.ws.rs.ext;

import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.util.Collection;

import javax.ws.rs.core.MediaType;

public interface InterceptorContext {

    public Object getProperty(String name);

    public Collection<String> getPropertyNames();

    public void setProperty(String name, Object object);

    public void removeProperty(String name);

    public Annotation[] getAnnotations();

    public void setAnnotations(Annotation[] annotations);

    Class<?> getType();

    public void setType(Class<?> type);

    Type getGenericType();

    public void setGenericType(Type genericType);

    public MediaType getMediaType();

    public void setMediaType(MediaType mediaType);
}
Copy to Clipboard Toggle word wrap

Sample implementation on the client side
复制链接

To implement an entity reader interceptor for the client side, define a class that implements the ReaderInterceptor interface.
For example, the following code shows an example of an entity reader interceptor for the client side (with a priority of 10), which replaces all instances of COMPANY_NAME by Red Hat in the message body of the incoming response: 
// Java
package org.jboss.fuse.example;
 
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
 
import javax.annotation.Priority;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.ext.ReaderInterceptor;
import javax.ws.rs.ext.ReaderInterceptorContext;
 
@Priority(value = 10)
public class SampleClientReaderInterceptor implements ReaderInterceptor {
 
  @Override
  public Object aroundReadFrom(ReaderInterceptorContext interceptorContext)
          throws IOException, WebApplicationException
  {
    InputStream inputStream = interceptorContext.getInputStream();
    byte[] bytes = new byte[inputStream.available()];
    inputStream.read(bytes);
    String responseContent = new String(bytes);
    responseContent = responseContent.replaceAll("COMPANY_NAME", "Red Hat");
    interceptorContext.setInputStream(new ByteArrayInputStream(responseContent.getBytes()));

    return interceptorContext.proceed();
  }
}
Copy to Clipboard Toggle word wrap

Sample implementation on the server side
复制链接

To implement an entity reader interceptor for the server side, define a class that implements the ReaderInterceptor interface and annotate it with the @Provider annotation.
For example, the following code shows an example of an entity reader interceptor for the server side (with a priority of 10), which replaces all instances of COMPANY_NAME by Red Hat in the message body of the incoming request: 
// Java
package org.jboss.fuse.example;
 
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
 
import javax.annotation.Priority;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.ext.Provider;
import javax.ws.rs.ext.ReaderInterceptor;
import javax.ws.rs.ext.ReaderInterceptorContext;
 
@Priority(value = 10)
@Provider
public class SampleServerReaderInterceptor implements ReaderInterceptor {

  @Override
  public Object aroundReadFrom(ReaderInterceptorContext interceptorContext)
          throws IOException, WebApplicationException {
    InputStream inputStream = interceptorContext.getInputStream();
    byte[] bytes = new byte[inputStream.available()];
    inputStream.read(bytes);
    String requestContent = new String(bytes);
    requestContent = requestContent.replaceAll("COMPANY_NAME", "Red Hat");
    interceptorContext.setInputStream(new ByteArrayInputStream(requestContent.getBytes()));

    return interceptorContext.proceed();
  }
}
Copy to Clipboard Toggle word wrap

Binding a reader interceptor on the client side
复制链接

Using the JAX-RS 2.0 client API, you can register an entity reader interceptor directly on a javax.ws.rs.client.Client object or on a javax.ws.rs.client.WebTarget object. Effectively, this means that the reader interceptor can optionally be applied to different scopes, so that only certain URI paths are affected by the interceptor.
For example, the following code shows how to register the SampleClientReaderInterceptor interceptor so that it applies to all invocations made using the client object: 
// Java
... 
import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.Invocation;
import javax.ws.rs.client.WebTarget;
import javax.ws.rs.core.Response;
...
Client client = ClientBuilder.newClient();
client.register(SampleClientReaderInterceptor.class);
Copy to Clipboard Toggle word wrap
For more details about registering interceptors with a JAX-RS 2.0 client, see ???.

Binding a reader interceptor on the server side
复制链接

To bind a reader interceptor on the server side (that is, to install it into the Apache CXF runtime), perform the following steps:
  1. Add the @Provider annotation to the reader interceptor class, as shown in the following code fragment: 
    // Java
package org.jboss.fuse.example;
...
import javax.annotation.Priority;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.ext.Provider;
import javax.ws.rs.ext.ReaderInterceptor;
import javax.ws.rs.ext.ReaderInterceptorContext;
 
@Priority(value = 10)
@Provider
public class SampleServerReaderInterceptor implements ReaderInterceptor {
  ...
}
    Copy to Clipboard Toggle word wrap
    When the reader interceptor implementation is loaded into the Apache CXF runtime, the REST implementation automatically scans the loaded classes to search for the classes marked with the @Provider annotation (the scanning phase).
  2. When defining a JAX-RS server endpoint in XML (for example, see Section 16.1, “Configuring JAX-RS Server Endpoints”), add the reader interceptor to the list of providers in the jaxrs:providers element. 
    <blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:jaxrs="http://cxf.apache.org/blueprint/jaxrs"
    xmlns:cxf="http://cxf.apache.org/blueprint/core"
    ...
>
    ...
    <jaxrs:server id="customerService" address="/customers">
      ...
      <jaxrs:providers>
        <ref bean="interceptorProvider" />
      </jaxrs:providers>
      <bean id="interceptorProvider" class="org.jboss.fuse.example.SampleServerReaderInterceptor"/>

    </jaxrs:server>

</blueprint>
    Copy to Clipboard Toggle word wrap
    Note
    This step is a non-standard requirement of Apache CXF. Strictly speaking, according to the JAX-RS standard, the @Provider annotation should be all that is required to bind the interceptor. But in practice, the standard approach is somewhat inflexible and can lead to clashing providers when many libraries are included in a large project.
返回顶部
Red Hat logoGithubredditYoutubeTwitter

学习

尝试、购买和销售

社区

关于红帽文档

通过我们的产品和服务，以及可以信赖的内容，帮助红帽用户创新并实现他们的目标。 了解我们当前的更新.

让开源更具包容性

红帽致力于替换我们的代码、文档和 Web 属性中存在问题的语言。欲了解更多详情，请参阅红帽博客.

關於紅帽

我们提供强化的解决方案，使企业能够更轻松地跨平台和环境（从核心数据中心到网络边缘）工作。

Theme

© 2025 Red Hat