elasticsearch 插件报错 org.apache.http.client.ClientProtocolException

配置：
```JSON
{
"writer": {
"parameter": {
"dynamic": false,
"indexType": "default",
"cleanup": false,
"accessKey": "elastic",
"index": "ordertest",
"settings": {
"index": {
"number_of_replicas": "1",
"number_of_shards": "5"
}
},
"column": [
{
"name": "id",
"type": "long"
},
{
"name": "order_id",
"type": "long"
},
{
"name": "merchant_id",
"type": "long"
},
{
"name": "order_name",
"type": "text"
},
{
"name": "gmt_create",
"type": "date"
},
{
"name": "gmt_modify",
"type": "date"
}
],
"batchSize": 1000,
"accessId": "elastic",
"discovery": false,
"endpoint": "es-cn-4590i74hi000awxw9.elasticsearch.aliyuncs.com",
"splitter": ","
},
"plugin": "elasticsearch"
}
}
```
异常信息：
```BASH
经DataX智能分析,该任务最可能的错误原因是:
com.alibaba.datax.common.exception.DataXException: Code:[ESWriter-03], Description:[mappings错误.]. - org.apache.http.client.ClientProtocolException
at com.alibaba.datax.common.exception.DataXException.asDataXException(DataXException.java:26)
at com.alibaba.datax.plugin.writer.elasticsearchwriter.ESWriter$Job.prepare(ESWriter.java:76)
at com.alibaba.datax.core.job.JobContainer.prepareJobWriter(JobContainer.java:947)
at com.alibaba.datax.core.job.JobContainer.prepare(JobContainer.java:391)
at com.alibaba.datax.core.job.JobContainer.start(JobContainer.java:165)
at com.alibaba.datax.core.Engine.start(Engine.java:96)
at com.alibaba.datax.core.Engine.entry(Engine.java:184)
at com.alibaba.datax.core.Engine.main(Engine.java:217)
```

Start with the supplied configuration and the stack trace at com.alibaba.datax.plugin.writer.elasticsearchwriter.ESWriter$Job.prepare, especially ESWriter.java:76. Reproduce the mappings error with the reported Elasticsearch endpoint and determine the relevant request failure; done means the configuration completes preparation without ClientProtocolException and the behavior is covered by a regression test.

Written by the indexing model from the issue text.