第 3 章 查询远程缓存
您可以在 Data Grid 服务器上索引和查询远程缓存。
3.1. 从 Hot Rod Java 客户端查询缓存
通过数据网格，您可以以编程方式通过 Hot Rod 端点从 Java 客户端查询远程缓存。此流程解释了如何索引查询存储 Book 实例的远程缓存。
先决条件
-
将 ProtoStream 处理器添加到
pom.xml中。
Data Grid 为 @ProtoField 注释提供此处理器，以便您可以生成 Protobuf 模式并执行查询。
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>...</version>
<configuration>
<annotationProcessorPaths>
<annotationProcessorPath>
<groupId>org.infinispan.protostream</groupId>
<artifactId>protostream-processor</artifactId>
<version>...</version>
</annotationProcessorPath>
</annotationProcessorPaths>
</configuration>
</plugin>
</plugins>
</build>流程
在类中添加索引注解，如下例所示：
Book.java
import org.infinispan.api.annotations.indexing.Basic; import org.infinispan.api.annotations.indexing.Indexed; import org.infinispan.api.annotations.indexing.Text; import org.infinispan.protostream.annotations.ProtoFactory; import org.infinispan.protostream.annotations.ProtoField; @Indexed public class Book { @Text @ProtoField(number = 1) final String title; @Text @ProtoField(number = 2) final String description; @Basic @ProtoField(number = 3, defaultValue = "0") final int publicationYear; @ProtoFactory Book(String title, String description, int publicationYear) { this.title = title; this.description = description; this.publicationYear = publicationYear; } // public Getter methods omitted for brevity }在新类中实施
SerializationContextInitializer接口，然后添加@ProtoSchema注释。-
使用
includeClasses参数引用包含@ProtoField注解的类。 -
定义 Protobuf 模式的名称，该模式使用
schemaFileName和schemaFilePath参数生成文件系统路径。 使用
schemaPackageName参数指定 Protobuf 模式的软件包名称。RemoteQueryInitializer.java
import org.infinispan.protostream.SerializationContextInitializer; import org.infinispan.protostream.annotations.ProtoSchema; @ProtoSchema( includeClasses = { Book.class }, schemaFileName = "book.proto", schemaFilePath = "proto/", schemaPackageName = "book_sample") public interface RemoteQueryInitializer extends SerializationContextInitializer { }
-
使用
编译您的项目。
此流程中的代码示例生成
proto/book.proto模式，以及 annotatedBook类的RemoteQueryInitializerImpl.java实现。
后续步骤
创建一个远程缓存，将 Data Grid 配置为索引您的实体。例如，以下远程缓存会在您在上一步中生成的 书.proto 模式中索引了 Book 实体：
<replicated-cache name="books">
<indexing>
<indexed-entities>
<indexed-entity>book_sample.Book</indexed-entity>
</indexed-entities>
</indexing>
</replicated-cache>
以下 RemoteQuery 类执行以下操作：
-
使用 Hot Rod Java 客户端注册
RemoteQueryInitializerImpl序列化上下文。 -
将 Protobuf 模式(
书.proto)注册到 Data Grid Server。 -
将两个
Book实例添加到远程缓存中。 - 根据标题中的关键字，执行与书书匹配的全文本查询。
RemoteQuery.java
package org.infinispan;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;
import org.infinispan.client.hotrod.RemoteCache;
import org.infinispan.client.hotrod.RemoteCacheManager;
import org.infinispan.client.hotrod.Search;
import org.infinispan.client.hotrod.configuration.ConfigurationBuilder;
import org.infinispan.query.dsl.Query;
import org.infinispan.query.dsl.QueryFactory;
import org.infinispan.query.remote.client.ProtobufMetadataManagerConstants;
public class RemoteQuery {
public static void main(String[] args) throws Exception {
ConfigurationBuilder clientBuilder = new ConfigurationBuilder();
// RemoteQueryInitializerImpl is generated
clientBuilder.addServer().host("127.0.0.1").port(11222)
.security().authentication().username("user").password("user")
.addContextInitializers(new RemoteQueryInitializerImpl());
RemoteCacheManager remoteCacheManager = new RemoteCacheManager(clientBuilder.build());
// Grab the generated protobuf schema and registers in the server.
Path proto = Paths.get(RemoteQuery.class.getClassLoader()
.getResource("proto/book.proto").toURI());
String protoBufCacheName = ProtobufMetadataManagerConstants.PROTOBUF_METADATA_CACHE_NAME;
remoteCacheManager.getCache(protoBufCacheName).put("book.proto", Files.readString(proto));
// Obtain the 'books' remote cache
RemoteCache<Object, Object> remoteCache = remoteCacheManager.getCache("books");
// Add some Books
Book book1 = new Book("Infinispan in Action", "Learn Infinispan with using it", 2015);
Book book2 = new Book("Cloud-Native Applications with Java and Quarkus", "Build robust and reliable cloud applications", 2019);
remoteCache.put(1, book1);
remoteCache.put(2, book2);
// Execute a full-text query
Query<Book> query = remoteCache.query("FROM book_sample.Book WHERE title:'java'");
List<Book> list = query.execute().list(); // Voila! We have our book back from the cache!
}
}
