[英]Custom ObjectMapper with Jersey 2.2 and Jackson 2.1
我正在努力使用 Grizzly、Jersey 和 Jackson 的 REST 應用程序,因為 Jersey 忽略了我的自定義 ObjectMapper。
POM依賴:
<dependencies>
<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-grizzly2-servlet</artifactId>
<version>2.2</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.jaxrs</groupId>
<artifactId>jackson-jaxrs-json-provider</artifactId>
<version>2.1.4</version>
</dependency>
</dependencies>
結果版本是:Grizzly 2.3.3、Jackson 2.1.4 和 Jersey 2.2。
主類(我想顯式注冊 Jersey 組件):
public class Main {
public static void main(String[] args) {
try {
ResourceConfig rc = new ResourceConfig();
rc.register(ExampleResource.class);
rc.register(ObjectMapperResolver.class);
HttpHandler handler = ContainerFactory.createContainer(
GrizzlyHttpContainer.class, rc);
URI uri = new URI("http://0.0.0.0:8080/");
HttpServer server = GrizzlyHttpServerFactory.createHttpServer(uri);
ServerConfiguration config = server.getServerConfiguration();
config.addHttpHandler(handler, "/");
server.start();
System.in.read();
} catch (ProcessingException | URISyntaxException | IOException e) {
throw new Error("Unable to create HTTP server.", e);
}
}
}
ObjectMapper 的 ContextResolver:
@Provider
@Produces(MediaType.APPLICATION_JSON)
public class ObjectMapperResolver implements ContextResolver<ObjectMapper> {
private final ObjectMapper mapper;
public ObjectMapperResolver() {
System.out.println("new ObjectMapperResolver()");
mapper = new ObjectMapper();
mapper.enable(SerializationFeature.INDENT_OUTPUT);
}
@Override
public ObjectMapper getContext(Class<?> type) {
System.out.println("ObjectMapperResolver.getContext(...)");
return mapper;
}
}
ObjectMapperResolver
構造函數和getContext
都不會被調用。 我錯過了什么? 我更喜歡使用 Jersey 2.2 和 Jackson 2.1,因為它是另一個庫的依賴項。
完整示例可以在 GitHub 上找到: https : //github.com/svenwltr/example-grizzly-jersey-jackson/tree/stackoverflow
以下解決方案適用於以下堆棧(如...這是我用來測試它的設置)
我正在添加我的消息以及我在這篇文章中提出的解決方案,因為它與我今天進行的許多 Google 搜索非常相關......這是一個繁瑣的解決方案,我認為這是一個更麻煩的問題。
jackson-jaxrs-json-provider
依賴項:<dependency>
<groupId>com.fasterxml.jackson.jaxrs</groupId>
<artifactId>jackson-jaxrs-json-provider</artifactId>
<version>2.4.1</version>
</dependency>
jersey-media-json-jackson
依賴項:<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-json-jackson</artifactId>
</dependency>
com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider
的@Provider
組件, com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider
所示:import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.ext.Provider;
@Provider
@Produces(MediaType.APPLICATION_JSON)
public class CustomJsonProvider extends JacksonJaxbJsonProvider {
private static ObjectMapper mapper = new ObjectMapper();
static {
mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
mapper.setSerializationInclusion(JsonInclude.Include.ALWAYS);
mapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
mapper.enable(SerializationFeature.INDENT_OUTPUT);
}
public CustomJsonProvider() {
super();
setMapper(mapper);
}
}
正如您所觀察到的,這也是我們定義com.fasterxml.jackson.databind.ObjectMapper
的自定義實例的com.fasterxml.jackson.databind.ObjectMapper
MarshallingFeature
擴展javax.ws.rs.core.Feature
像這樣:import javax.ws.rs.core.Feature;
import javax.ws.rs.core.FeatureContext;
import javax.ws.rs.ext.MessageBodyReader;
import javax.ws.rs.ext.MessageBodyWriter;
public class MarshallingFeature implements Feature {
@Override
public boolean configure(FeatureContext context) {
context.register(CustomJsonProvider.class, MessageBodyReader.class, MessageBodyWriter.class);
return true;
}
}
org.glassfish.jersey.server.ResourceConfig
像這樣配置您的應用程序:import org.glassfish.jersey.server.ResourceConfig;
...
public class MyApplication extends ResourceConfig {
public MyApplication() {
...
register(MarshallingFeature.class);
...
}
}
其他注意事項和觀察:
javax.ws.rs.core.Response
來包裝控制器的響應,此解決方案都適用。com.fasterxml.jackson.databind.ObjectMapper
的自定義配置的com.fasterxml.jackson.databind.ObjectMapper
。很抱歉把球丟在這個@jcreason 上,我希望你仍然是好奇心。 所以我檢查了去年的代碼,這就是我提供自定義映射器的想法。
問題是在特性初始化期間,任何自定義對象映射器都會被某些代碼禁用
org.glassfish.jersey.jackson.JacksonFeature:77 (jersey-media-json-jackson-2.12.jar)
// Disable other JSON providers.
context.property(PropertiesHelper.getPropertyNameForRuntime(InternalProperties.JSON_FEATURE, config.getRuntimeType()), JSON_FEATURE);
但是這個功能只會被這個組件注冊
org.glassfish.jersey.jackson.internal.JacksonAutoDiscoverable
if (!context.getConfiguration().isRegistered(JacksonFeature.class)) {
context.register(JacksonFeature.class);
}
所以我所做的是注冊我自己的功能,該功能注冊了我自己的對象映射器提供程序,並在絆線中阻止 org.glassfish.jersey.jackson.JacksonFeature 被注冊並覆蓋我的對象映射器......
import com.fasterxml.jackson.jaxrs.base.JsonMappingExceptionMapper;
import com.fasterxml.jackson.jaxrs.base.JsonParseExceptionMapper;
import org.glassfish.jersey.internal.InternalProperties;
import org.glassfish.jersey.internal.util.PropertiesHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.ws.rs.core.Configuration;
import javax.ws.rs.core.Feature;
import javax.ws.rs.core.FeatureContext;
import javax.ws.rs.ext.MessageBodyReader;
import javax.ws.rs.ext.MessageBodyWriter;
public class MarshallingFeature implements Feature {
private final static String JSON_FEATURE = MarshallingFeature.class.getSimpleName();
@Override
public boolean configure(FeatureContext context) {
context.register(JsonParseExceptionMapper.class);
context.register(JsonMappingExceptionMapper.class);
context.register(JacksonJsonProviderAtRest.class, MessageBodyReader.class, MessageBodyWriter.class);
final Configuration config = context.getConfiguration();
// Disables discoverability of org.glassfish.jersey.jackson.JacksonFeature
context.property(
PropertiesHelper.getPropertyNameForRuntime(InternalProperties.JSON_FEATURE,
config.getRuntimeType()), JSON_FEATURE);
return true;
}
}
這是自定義對象映射器提供程序...
import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.ext.Provider;
@Provider
@Produces(MediaType.APPLICATION_JSON)
public class JacksonJsonProviderAtRest extends JacksonJaxbJsonProvider {
private static ObjectMapper objectMapperAtRest = new ObjectMapper();
static {
objectMapperAtRest.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
objectMapperAtRest.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
objectMapperAtRest.configure(SerializationFeature.INDENT_OUTPUT, true); // Different from default so you can test it :)
objectMapperAtRest.setSerializationInclusion(JsonInclude.Include.ALWAYS);
}
public JacksonJsonProviderAtRest() {
super();
setMapper(objectMapperAtRest);
}
}
我找到了解決方案。 我必須自己實例化 Jackson Provider 並設置我的自定義ObjectMapper
。 可以在 GitHub 上找到一個工作示例: https : //github.com/svenwltr/example-grizzly-jersey-jackson/tree/stackoverflow-answer
我刪除了我的ObjectMapperResolver
並修改了我的main
方法:
public class Main {
public static void main(String[] args) {
try {
// create custom ObjectMapper
ObjectMapper mapper = new ObjectMapper();
mapper.enable(SerializationFeature.INDENT_OUTPUT);
// create JsonProvider to provide custom ObjectMapper
JacksonJaxbJsonProvider provider = new JacksonJaxbJsonProvider();
provider.setMapper(mapper);
// configure REST service
ResourceConfig rc = new ResourceConfig();
rc.register(ExampleResource.class);
rc.register(provider);
// create Grizzly instance and add handler
HttpHandler handler = ContainerFactory.createContainer(
GrizzlyHttpContainer.class, rc);
URI uri = new URI("http://0.0.0.0:8080/");
HttpServer server = GrizzlyHttpServerFactory.createHttpServer(uri);
ServerConfiguration config = server.getServerConfiguration();
config.addHttpHandler(handler, "/");
// start
server.start();
System.in.read();
} catch (ProcessingException | URISyntaxException | IOException e) {
throw new Error("Unable to create HTTP server.", e);
}
}
}
我想通了這一點,基於一點修補。
問題似乎出在 Jersey 的功能自動檢測機制中。 如果您依賴 Jersey 加載 JacksonJaxbJsonProvider,那么您的 ObjectMapper 的自定義上下文提供程序將被忽略。 相反,如果您手動注冊該功能,則它可以工作。 我假設這與將自動檢測到的提供程序加載到不同的上下文范圍有關,但至於解決方案,這就是我最終得到的。 請注意,我將它封裝到一個功能中,您應該可以毫無問題地直接在您的應用程序中注冊它。
public final class RequestMappingFeature implements Feature {
@Override
public boolean configure(final FeatureContext context) {
context.register(ObjectMapperProvider.class);
// If you comment out this line, it stops working.
context.register(JacksonJaxbJsonProvider.class);
return true;
}
}
2017 年 11 月更新:Jersey2 世界發生了一些變化。 如果上述方法不起作用,請嘗試以下操作:
提供您自己的 ObjectMapper 的新方法現在看起來像這樣:
public final class JacksonFeature implements Feature {
private static final ObjectMapper MAPPER;
static {
// Create the new object mapper.
MAPPER = new ObjectMapper();
// Enable/disable various configuration flags.
MAPPER.configure(
DeserializationFeature.READ_ENUMS_USING_TO_STRING, true);
// ... Add your own configurations here.
}
@Override
public boolean configure(final FeatureContext context) {
JacksonJaxbJsonProvider provider = new JacksonJaxbJsonProvider(
MAPPER, DEFAULT_ANNOTATIONS);
context.register(provider);
return true;
}
}
請這樣做:
1) 添加 pom.xml 依賴
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-json-jackson</artifactId>
<version>2.2</version>
</dependency>
2) 在 Main.java 中注冊 JacksonFeature
public class Main {
public static void main(String[] args) {
try {
ResourceConfig rc = new ResourceConfig();
rc.register(ExampleResource.class);
rc.register(ObjectMapperResolver.class);
rc.register(JacksonFeature.class);
HttpHandler handler = ContainerFactory.createContainer(
GrizzlyHttpContainer.class, rc);
URI uri = new URI("http://0.0.0.0:8080/");
HttpServer server = GrizzlyHttpServerFactory.createHttpServer(uri);
ServerConfiguration config = server.getServerConfiguration();
config.addHttpHandler(handler, "/");
server.start();
System.in.read();
} catch (ProcessingException | URISyntaxException | IOException e) {
throw new Error("Unable to create HTTP server.", e);
}
}
}
3) 在你的資源中使用 org.codehaus.jackson.map.ObjectMapper
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.ext.ContextResolver;
import javax.ws.rs.ext.Provider;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.SerializationConfig.Feature;
@Provider
@Produces(MediaType.APPLICATION_JSON)
public class ObjectMapperResolver implements ContextResolver<ObjectMapper> {
private final ObjectMapper mapper;
public ObjectMapperResolver() {
System.out.println("new ObjectMapperResolver()");
mapper = new ObjectMapper();
mapper.enable(Feature.INDENT_OUTPUT);
}
@Override
public ObjectMapper getContext(Class<?> type) {
System.out.println("ObjectMapperResolver.getContext(...)");
return mapper;
}
}
由於我花了幾個小時才能使用 Java EE7 和 Glassfish4,這是我的解決方案:
@javax.ws.rs.ApplicationPath("withJackson")
public class ApplicationConfig extends Application {
private static final Logger log = java.util.logging.Logger.getLogger(ApplicationConfig.class.getName());
@Override
public Set<Object> getSingletons() {
Set<Object> set = new HashSet<>();
log.log(Level.INFO, "Enabling custom Jackson JSON provider");
set.add(new JacksonJsonProvider().configure(SerializationFeature.INDENT_OUTPUT, true));
return set;
}
@Override
public Map<String, Object> getProperties() {
Map<String, Object> map = new HashMap<>();
log.log(Level.INFO, "Disabling MOXy JSON provider");
map.put("jersey.config.disableMoxyJson.server", true);
return map;
}
@Override
public Set<Class<?>> getClasses() {
Set<Class<?>> resources = new java.util.HashSet<>();
addRestResourceClasses(resources);
return resources;
}
/**
* Do not modify addRestResourceClasses() method.
* It is automatically populated with
* all resources defined in the project.
* If required, comment out calling this method in getClasses().
*/
private void addRestResourceClasses(Set<Class<?>> resources) {
resources.add(com.fasterxml.jackson.jaxrs.base.JsonMappingExceptionMapper.class);
resources.add(com.fasterxml.jackson.jaxrs.base.JsonParseExceptionMapper.class);
resources.add(com.fasterxml.jackson.jaxrs.json.JsonMappingExceptionMapper.class);
resources.add(com.fasterxml.jackson.jaxrs.json.JsonParseExceptionMapper.class);
resources.add(de.lathspell.java_test_ee7_json.Api.class);
resources.add(de.lathspell.java_test_ee7_json.with_jackson.MyExceptionMapper.class);
}
唯一相關的 POM 依賴項是:
<dependency>
<groupId>com.fasterxml.jackson.jaxrs</groupId>
<artifactId>jackson-jaxrs-json-provider</artifactId>
<version>2.2.3</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.2.3</version>
</dependency>
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-web-api</artifactId>
<version>7.0</version>
<scope>provided</scope>
</dependency>
來自 Jersey 2.17 文檔: https : //eclipse-ee4j.github.io/jersey.github.io/documentation/2.17/media.html#jackson-registration
在申請中
@ApplicationPath("/")
public class MyApplication extends ResourceConfig {
public MyApplication() {
register(JacksonFeature.class);
// This is the class that you supply, Call it what you want
register(JacksonObjectMapperProvider.class);
//...
}
}
編輯,忘記添加您在 register(..) 中提供的 JacksonObjectMapperProvider:
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
import javax.ws.rs.ext.ContextResolver;
import javax.ws.rs.ext.Provider;
@Provider
public class JacksonObjectMapperProvider implements ContextResolver<ObjectMapper>{
final ObjectMapper defaultObjectMapper;
public JacksonObjectMapperProvider() {
defaultObjectMapper = createDefaultMapper();
}
@Override
public ObjectMapper getContext(Class<?> type) {return defaultObjectMapper;}
public static ObjectMapper createDefaultMapper() {
final ObjectMapper jackson = new ObjectMapper();
// any changes to the ObjectMapper is up to you. Do what you like.
// The ParameterNamesModule is optional,
// it enables you to have immutable POJOs in java8
jackson.registerModule(new ParameterNamesModule());
jackson.enable(SerializationFeature.INDENT_OUTPUT);
jackson.disable(SerializationFeature.WRITE_EMPTY_JSON_ARRAYS);
jackson.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
return jackson;
}
}
使用 Jackson 2.7,這不起作用:
public class MyApplication extends ResourceConfig {
public MyApplication() {
register(MyObjectMapperProvider.class);
}}
調用了 MyObjectMapperProvider 構造函數,但從未調用過 getContext() 。
在 super() 構造函數中注冊 MyObjectMapperProvider 使其工作:
public class MyApplication extends ResourceConfig {
public MyApplication() {
super(
// register Jackson ObjectMapper resolver
MyObjectMapperProvider.class
);
}}
請參閱此 Jersey 示例代碼。
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