ES7學習日記——Java REST Client索引管理：判斷索引存在、獲取Settings、獲取Mappings

Java REST Client索引管理的一般步驟：

1. 創建相關請求對象
2. 執行請求
3. 查看請求結果

一、判斷索引是否存在

        RestHighLevelClient client=new RestHighLevelClient(RestClient.builder(new HttpHost("localhost",9200,"http")));
        GetIndexRequest exist=new GetIndexRequest("blog");
        boolean exists=client.indices().exists(exist, RequestOptions.DEFAULT);

　　如果索引存在，則exists布爾值為真

二、獲取Settings

　　　　GetSettingsRequest getSettings=new GetSettingsRequest().indices("blog");
　　　　GetSettingsResponse getSettingsResponse=client.indices().getSettings(getSettings, RequestOptions.DEFAULT);
　　　　String numberOfShardsString = getSettingsResponse.getSetting("index", "index.number_of_shards");

三、獲取mappings

        GetMappingsRequest getMappings=new GetMappingsRequest().indices("blog");
        GetMappingsResponse getMappingResponse = client.indices().getMapping(getMappings, RequestOptions.DEFAULT);
        Map<String, MappingMetaData> allMappings = getMappingResponse.mappings(); 
        MappingMetaData indexMapping = allMappings.get("blog"); 
        Map<String, Object> mapping = indexMapping.sourceAsMap();
        Iterator<Entry<String,Object>> entries=mapping.entrySet().iterator();
        while(entries.hasNext()){
            Entry<String, Object> entry = entries.next();
            String key = entry.getKey();
            Object value = entry.getValue();
            System.out.println(key+":"+value);
        }