Simple example (#528)

Signed-off-by: yhmo <yihua.mo@zilliz.com>

examples/main/java/io/milvus/SimpleExample.java

@@ -0,0 +1,147 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package io.milvus;
+
+import com.alibaba.fastjson.JSONObject;
+import io.milvus.client.MilvusServiceClient;
+import io.milvus.grpc.*;
+import io.milvus.param.*;
+import io.milvus.param.collection.*;
+import io.milvus.param.dml.*;
+import io.milvus.param.index.*;
+import io.milvus.response.*;
+import java.util.*;
+
+public class SimpleExample {
+    private static final String COLLECTION_NAME = "hello_milvus";
+    private static final String ID_FIELD = "book_id";
+    private static final String VECTOR_FIELD = "book_intro";
+    private static final String TITLE_FIELD = "book_title";
+    private static final Integer VECTOR_DIM = 4;
+
+    public static void main(String[] args) {
+        // Connect to Milvus server. Replace the "localhost" and port with your Milvus server address.
+        MilvusServiceClient milvusClient = new MilvusServiceClient(ConnectParam.newBuilder()
+                .withHost("localhost")
+                .withPort(19530)
+                .build());
+
+        // Define fields
+        List<FieldType> fieldsSchema = Arrays.asList(
+                FieldType.newBuilder()
+                        .withName(ID_FIELD)
+                        .withDataType(DataType.Int64)
+                        .withPrimaryKey(true)
+                        .withAutoID(false)
+                        .build(),
+                FieldType.newBuilder()
+                        .withName(VECTOR_FIELD)
+                        .withDataType(DataType.FloatVector)
+                        .withDimension(VECTOR_DIM)
+                        .build(),
+                FieldType.newBuilder()
+                        .withName(TITLE_FIELD)
+                        .withDataType(DataType.VarChar)
+                        .withMaxLength(64)
+                        .build()
+        );
+
+        // Create the collection with 3 fields
+        R<RpcStatus> ret = milvusClient.createCollection(CreateCollectionParam.newBuilder()
+                .withCollectionName(COLLECTION_NAME)
+                .withFieldTypes(fieldsSchema)
+                .build());
+        if (ret.getStatus() != R.Status.Success.getCode()) {
+            throw new RuntimeException("Failed to create collection! Error: " + ret.getMessage());
+        }
+
+        // Specify an index type on the vector field.
+        ret = milvusClient.createIndex(CreateIndexParam.newBuilder()
+                .withCollectionName(COLLECTION_NAME)
+                .withFieldName(VECTOR_FIELD)
+                .withIndexType(IndexType.FLAT)
+                .withMetricType(MetricType.L2)
+                .build());
+        if (ret.getStatus() != R.Status.Success.getCode()) {
+            throw new RuntimeException("Failed to create index! Error: " + ret.getMessage());
+        }
+
+        // Call loadCollection() to enable automatically loading data into memory for searching
+        milvusClient.loadCollection(LoadCollectionParam.newBuilder()
+                .withCollectionName(COLLECTION_NAME)
+                .build());
+
+        // Insert 10 records into the collection
+        List<JSONObject> rows = new ArrayList<>();
+        for (long i = 1L; i <= 10; ++i) {
+            JSONObject row = new JSONObject();
+            row.put(ID_FIELD, i);
+            List<Float> vector = Arrays.asList((float)i, (float)i, (float)i, (float)i);
+            row.put(VECTOR_FIELD, vector);
+            row.put(TITLE_FIELD, "Tom and Jerry " + i);
+            rows.add(row);
+        }
+
+        R<MutationResult> insertRet = milvusClient.insert(InsertParam.newBuilder()
+                .withCollectionName(COLLECTION_NAME)
+                .withRows(rows)
+                .build());
+        if (insertRet.getStatus() != R.Status.Success.getCode()) {
+            throw new RuntimeException("Failed to insert! Error: " + insertRet.getMessage());
+        }
+
+        // Call flush to make sure the inserted records are consumed by Milvus server, so that the records
+        // be searchable immediately. Just a special action in this example.
+        // In practice, you don't need to call flush() frequently.
+        milvusClient.flush(FlushParam.newBuilder()
+                .addCollectionName(COLLECTION_NAME)
+                .build());
+
+        // Construct a vector to search top5 similar records, return the book title for us.
+        // This vector is equal to the No.3 record, we suppose the No.3 record is the most similar.
+        List<Float> vector = Arrays.asList(3.0f, 3.0f, 3.0f, 3.0f);
+        R<SearchResults> searchRet = milvusClient.search(SearchParam.newBuilder()
+                .withCollectionName(COLLECTION_NAME)
+                .withMetricType(MetricType.L2)
+                .withTopK(5)
+                .withVectors(Arrays.asList(vector))
+                .withVectorFieldName(VECTOR_FIELD)
+                .withParams("{}")
+                .addOutField(TITLE_FIELD)
+                .build());
+        if (searchRet.getStatus() != R.Status.Success.getCode()) {
+            throw new RuntimeException("Failed to search! Error: " + searchRet.getMessage());
+        }
+
+        // The search() allows multiple target vectors to search in a batch.
+        // Here we only input one vector to search, get the result of No.0 vector to print out
+        SearchResultsWrapper resultsWrapper = new SearchResultsWrapper(searchRet.getData().getResults());
+        List<SearchResultsWrapper.IDScore> scores = resultsWrapper.getIDScore(0);
+        System.out.println("The result of No.0 target vector:");
+        for (SearchResultsWrapper.IDScore score:scores) {
+            System.out.println(score);
+        }
+
+        // drop the collection if you don't need the collection anymore
+        milvusClient.dropCollection(DropCollectionParam.newBuilder()
+                .withCollectionName(COLLECTION_NAME)
+                .build());
+    }
+}