安装必要的包：pymongo、elasticsearch

bash pip install pymongo elasticsearch

连接MongoDB和Elasticsearch

```python
import pymongo
from elasticsearch import Elasticsearch

连接MongoDB

mongo_client = pymongo.MongoClient('localhost', 27017)
db = mongo_client['database_name']

连接Elasticsearch

es = Elasticsearch()
```

将MongoDB数据导入到Elasticsearch

```python

获取MongoDB中的数据

data = db.collection_name.find()

逐条导入数据到Elasticsearch

for item in data:
# 构造Elasticsearch中的文档
doc = {
'field1': item['mongo_field1'],
'field2': item['mongo_field2'],
# ...
}

# 将文档导入Elasticsearch
es.index(index='index_name', doc_type='doc_type', body=doc)

```

调整Elasticsearch的mapping（如果需要）

如果需要更改Elasticsearch的mapping，可以通过以下方法实现：

```python

设置mapping

mapping = {
'properties': {
'field1': {'type': 'text'},
'field2': {'type': 'integer'},
# ...
}
}

创建index并设置mapping

es.indices.create(index='index_name', body={'mappings': mapping})
```

完整代码示例

```python
import pymongo
from elasticsearch import Elasticsearch

连接MongoDB

mongo_client = pymongo.MongoClient('localhost', 27017)
db = mongo_client['database_name']

连接Elasticsearch

es = Elasticsearch()

设置mapping

mapping = {
'properties': {
'field1': {'type': 'text'},
'field2': {'type': 'integer'},
# ...
}
}

创建index并设置mapping

es.indices.create(index='index_name', body={'mappings': mapping})

获取MongoDB中的数据

data = db.collection_name.find()

逐条导入数据到Elasticsearch

for item in data:
# 构造Elasticsearch中的文档
doc = {
'field1': item['mongo_field1'],
'field2': item['mongo_field2'],
# ...
}

# 将文档导入Elasticsearch
es.index(index='index_name', doc_type='doc_type', body=doc)

```