shell解析json工具-jq

本文主要包括：

• json解析工具-jq简介

jq简介

jq可以对json数据进行分片、过滤、映射和转换，和sed、awk、grep等命令一样，都可以让你轻松地把玩文本。它能轻松地把你拥有的数据转换成你期望的格式，而且需要写的程序通常也比你期望的更加简短。

jq安装

在Linux下安装：

# 安装EPEL源：
yum install -y epel-release
 
# 安装完EPEL源后，可以查看下jq包是否存在：
yum list jq
 
# 安装jq：
yum install -y jq

使用案例

1. 使用 jq 美化 json 数据

   jsonStr='{"name":"springcloud","processDefinitionId":"","failureStrategy":"CONTINUE","warningType":"NONE","warningGroupId":"0","taskDependType":"TASK_POST","runMode":"RUN_MODE_SERIAL","processInstancePriority":"MEDIUM","workerGroup":"default","runParam":[{"T_SID":"tenantId","INS_NO":"inspectionNo","partitionFields":"partitionFields","batchNo":"111","groupBy":"battery_voltage,","orderBy":"d,e","startLine":"3","endLine":"63","calculationType":"1","matchNo":"aaaaaaaaa1","planNo":"bbbbbbbb2","sampleNo":"ccccccc3","analysisModelNo":"aaaa","startRowNo":"1","endRowNo":"1000"}]}'
   echo $jsonStr | jq .
   # 输出为：
   {
     "name": "springcloud",
     "processDefinitionId": "",
     "failureStrategy": "CONTINUE",
     "warningType": "NONE",
     "warningGroupId": "0",
     "taskDependType": "TASK_POST",
     "runMode": "RUN_MODE_SERIAL",
     "processInstancePriority": "MEDIUM",
     "workerGroup": "default",
     "runParam": [
       {
         "T_SID": "tenantId",
         "INS_NO": "inspectionNo",
         "partitionFields": "partitionFields",
         "batchNo": "111",
         "groupBy": "battery_voltage,",
         "orderBy": "d,e",
         "startLine": "3",
         "endLine": "63",
         "calculationType": "1",
         "matchNo": "aaaaaaaaa1",
         "planNo": "bbbbbbbb2",
         "sampleNo": "ccccccc3",
         "analysisModelNo": "aaaa",
         "startRowNo": "1",
         "endRowNo": "1000"
       }
     ]
   }

2. 获取key的值

   echo $jsonStr | jq -r '.name'
   # 输出  springcloud
   
   # 输出多个索引的值，可以用逗号分割
   echo $jsonStr | jq -r '.name,.failureStrategy'

3. 数组操作 .[], .[i], .[s:e],[s:],[:e]

   # 语法：jq '.[s:e]',返回的是数组或者列表的index从s开始（包括s）到e结束（不包括e）
   # jq '.[i]'代表取数组第i位，从0开始
   # [[s:],[:e] 分别代表取从s开始直到结尾/从头开始直到e
   echo '[{"name":"JSON", "good":true}, {"name":"XML", "good":false}]' | jq -r '.[1]'
   # 输出值
   {
     "name": "XML",
     "good": false
   }
   
   

4. 构造数组/对象 [], {}

   echo '{"user":"stedolan","titles":["JQ Primer", "More JQ"]}' | jq -r '{user, title: .titles[]}'
   # 输出：
   {
     "user": "stedolan",
     "title": "JQ Primer"
   }
   {
     "user": "stedolan",
     "title": "More JQ"
   }

5. 括号的作用

   # 可以直接计算加减乘除
   echo 1 | jq '(.+2)*5'    # 15
   echo {1,2,3} | jq '(.+2)*5'  # 15 20 25

6. length求长度

   #如果是字符串是求的字符串的长度，如果是数组则求得是数组的长度
   echo '[{"name":"JSON", "good":true}, {"name":"XML", "good":false}]' | jq -r '. | length'   # 2
   echo '[{"name":"JSON", "good":true}, {"name":"XML", "good":false,"a":1}]' | jq -r '.[] | length'  # 2 3
   echo $jsonStr | jq -r '.name | length'   # 11

7. 输出所有的keys

   echo $jsonStr | jq -r 'keys'   
   # [
   #   "failureStrategy",
   #   "name",
   #   "processDefinitionId",
   #   "processInstancePriority",
   #   "runMode",
   #   "runParam",
   #   "taskDependType",
   #   "warningGroupId",
   #   "warningType",
   #   "workerGroup"
   # ]

8. 判断存不存在某个键

   echo $jsonStr | jq 'has("name")'  # true
   echo $jsonStr | jq 'has("aaa")'  # false

9. 字符插入 \(foo)

   echo '42' | jq '"The input was \(.), which is one less than \(.+1)"'
   # "The input was 42, which is one less than 43"

10. if-then-else-end 条件

    echo '2' | jq 'if . == 0 then "zero" elif . == 1 then "one" else "many" end' # many