使用multi get API可以通過索引名、型別名、文件id一次得到一個文件集合，文件可以來自同一個索引庫，也可以來自不同索引庫。示例如下:

MultiGetResponse multiGetItemResponses = client.prepareMultiGet()
    .add("twitter", "tweet", "1")    //註釋1                            
    .add("twitter", "tweet", "2", "3", "4")     //註釋2             
    .add("another", "type"
 
, "foo")          //註釋3                   
    .get();

for (MultiGetItemResponse itemResponse : multiGetItemResponses) {       //註釋4
    GetResponse response = itemResponse.getResponse();
    if (response.isExists()) {                   //註釋5               
        String json = response.getSourceAsString();    //註釋6                 
 

    }
}

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註釋1: 通過單一的ID獲取一個文件. 
註釋2：傳入多個id，從相同的索引名/型別名中獲取多個文件. 
註釋3：可以同時獲取不同索引中的文件. 
註釋4：遍歷結果集. 
註釋5：檢驗文件是否存在. 
註釋6：獲取文件源.

一、獲取索引的所有mapping

通過java客戶端獲取mapping：

package elasticsearch.in.action.client;

import java.net.InetAddress;
import java.net.UnknownHostException;

import org.elasticsearch
 
.client.transport.TransportClient;
import org.elasticsearch.cluster.metadata.MappingMetaData;
import org.elasticsearch.common.collect.ImmutableOpenMap;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.InetSocketTransportAddress;

public class TransClient {
    public static String clusterName = "elasticsearch";// 叢集名稱
    public static String serverIP = "127.0.0.1";// 伺服器IP
    public static void main(String[] args) {
        System.out.println(getMapping("news", "sportnews"));
    }

    public static String getMapping(String indexname, String typename) {
        Settings settings = Settings.settingsBuilder().put("cluster.name", clusterName).build();
        String mapping="";
        try {
            TransportClient client = TransportClient.builder().settings(settings).build()
                    .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName(serverIP), 9300));

            ImmutableOpenMap<String, MappingMetaData> mappings = client.admin().cluster().prepareState().execute()
                    .actionGet().getState().getMetaData().getIndices().get(indexname).getMappings();
            mapping = mappings.get(typename).source().toString();


            client.close();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }

        return mapping;
    }

}

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二、獲取所有的type以及每個type的mapping

mapping資訊都是ImmutableOpenMap

for (ObjectObjectCursor<String, MappingMetaData> cursor : mappings) {
            System.out.println(cursor.key); // 索引下的每個type
            System.out.println(cursor.value.getSourceAsMap()); // 每個type的mapping
}