通过_source字段中的include和exclude来指定返回结果包含哪些字段，排除哪些字段。
举例：根据关系单号，查询es，设置_source的include和exclude：
{
"_source":{
"include":[
"policyNo",
"policyRelationNo",
"policyStatus"
],
"exclude":[
"salesType"
]
},
"query": {
"bool": {
"must": [
{
"term": {
"policyRelationNo": "KR01435021"
}
}
],
"should": [],
"must_not": []
}
},
"from": 0,
"size": 10
}