spring Mongodb查询索引报错 java.lang.NumberFormatException: empty String

笔者在mongo3.4/4.0环境下使用以下命令创建索引，

db.getCollection("xxx.com").createIndex({
    mobile: ""
}, {
    name: "mobile_mac"
})

执行以下demo查询索引

mongoTemplate.indexOps(collection).getIndexInfo(); #笔者正式环境不是这么写的，这里方便大家理解，使用语法糖方式的代码 ;p

每次走到xxx.com表的时候总是报错

Exception in thread "Configuration Initializer" java.lang.NumberFormatException: empty String
    at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1842)
    at sun.misc.FloatingDecimal.parseDouble(FloatingDecimal.java:110)
    at java.lang.Double.parseDouble(Double.java:538)
    at java.lang.Double.<init>(Double.java:608)
    at org.springframework.data.mongodb.core.IndexConverters.lambda$getDocumentIndexInfoConverter$1(IndexConverters.java:147)
    at org.springframework.data.mongodb.core.DefaultIndexOperations$1.getIndexData(DefaultIndexOperations.java:126)
    at org.springframework.data.mongodb.core.DefaultIndexOperations$1.doInCollection(DefaultIndexOperations.java:116)
    at org.springframework.data.mongodb.core.DefaultIndexOperations$1.doInCollection(DefaultIndexOperations.java:110)
    at org.springframework.data.mongodb.core.DefaultIndexOperations.execute(DefaultIndexOperations.java:141)
    at org.springframework.data.mongodb.core.DefaultIndexOperations.getIndexInfo(DefaultIndexOperations.java:110)
    at com.xmd.model.db.MongoDBHelper$1.run(MongoDBHelper.java:97)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

最初怀疑是框架bug，想整合新版本（2.13）进去，浪费了好久时间最终没能成功，回到了2.0.0.M1。

本地是jar版本是托管给maven，maven上没有该版本的源代码，最终硬着头皮调试。

用navicat mongo查看索引，的确是没有排序

后来想到mongo控制台创建索引有1,-1两个值，回想起来。1是正序 -1是倒序。于是到官方查询文档

db.collection.createIndex(keys, options)

For an ascending index on a field, specify a value of 1; for descending index, specify a value of -1.

到这里基本解决问题了，方法如下:

1、删除索引

db.getCollection(‘xxx.com‘).dropIndex("mobile_mac")

2、重建索引

db.getCollection("xxx.com").createIndex({
    mobile: 1
}, {
    name: "mobile_mac"
})

原文地址：https://www.cnblogs.com/passedbylove/p/10263790.html