Java监控MongoDB空间使用量、连接数

最近在做一个Java开发的监控系统，里面有一个模块是监控MongoDB的。看到网络上比较少这块资料，特记录如下：
1.下载MongoDB的Java驱动包。
2.获取空间使用量等数据：

CommandResult stats=db.getStats();

获取到的数据如下：

{
    "serverUsed": "172.1.1.3:15080",
    "db": "monitor",
    "collections": 27,
    "objects": 26358,
    "avgObjSize": 1044.4045830487898,
    "dataSize": 27528416,
    "storageSize": 53030912,
    "numExtents": 73,
    "indexes": 25,
    "indexSize": 1062880,
    "fileSize": 1006632960,
    "nsSizeMB": 16,
    "dataFileVersion": { "major": 4, "minor": 5 },
    "extentFreeList": { "num": 71, "totalSize": 654319616 },
    "ok": 1.0 }

3.获取连接数等数据：

CommandResult stats=db.command("serverStatus");

获取到的数据如下：

{
    "serverUsed": "172.1.1.3:15080",
    "host": "docker:80",
    "version": "2.6.6",
    "process": "mongod",
    "pid": 49,
    "uptime": 687177.0,
    "uptimeMillis": 687177657,
    "uptimeEstimate": 679910.0,
    "localTime": { "$date": "2016-03-08T16:15:46.815Z" },
    "asserts": { "regular": 1, "warning": 1, "msg": 0, "user": 58812, "rollovers": 0 },
    "backgroundFlushing": { "flushes": 11452, "total_ms": 143088, "average_ms": 12.494586098498079, "last_ms": 78, "last_finished": { "$date": "2016-03-08T16:14:50.610Z" } },
    "connections": { "current": 13, "available": 806, "totalCreated": 1794 },
    "cursors": { "note": "deprecated, use server status metrics", "clientCursors_size": 0, "totalOpen": 0, "pinned": 0, "totalNoTimeout": 38, "timedOut": 3 },
    "dur": { "commits": 29, "journaledMB": 0.008192, "writeToDataFilesMB": 0.003634, "compression": 2.0262181548355183, "commitsInWriteLock": 0, "earlyCommits": 0, "timeMs": { "dt": 3009, "prepLogBuffer": 0, "writeToJournal": 40, "writeToDataFiles": 0, "remapPrivateView": 0 } },
    "extra_info": { "note": "fields vary by platform", "heap_usage_bytes": 67277952, "page_faults": 692 },
    "globalLock": { "totalTime": 687177659000, "lockTime": 47304462, "currentQueue": { "total": 0, "readers": 0, "writers": 0 }, "activeClients": { "total": 0, "readers": 0, "writers": 0 } },
    "indexCounters": { "accesses": 431329, "hits": 431329, "misses": 0, "resets": 0, "missRatio": 0.0 },
    "locks": { ".": { "timeLockedMicros": { "R": 9599442, "W": 47304462 }, "timeAcquiringMicros": { "R": 4543336, "W": 1125820 } }, "admin": { "timeLockedMicros": { "r": 2625360, "w": 0 }, "timeAcquiringMicros": { "r": 158482, "w": 0 } } },
    "network": { "bytesIn": 96033519, "bytesOut": 177762851, "numRequests": 878581 },
    "opcounters": { "insert": 108167, "query": 262770, "update": 1014, "delete": 6, "getmore": 50, "command": 632623 },
    "opcountersRepl": { "insert": 0, "query": 0, "update": 0, "delete": 0, "getmore": 0, "command": 0 },
    "recordStats": { "accessesNotInMemory": 2, "pageFaultExceptionsThrown": 1, "admin": { "accessesNotInMemory": 0, "pageFaultExceptionsThrown": 0 } },
    "writeBacksQueued": false,
    "mem": { "bits": 64, "resident": 196, "virtual": 4782, "supported": true, "mapped": 2000, "mappedWithJournal": 4000 },
    "metrics": { "cursor": { "timedOut": 3, "open": { "noTimeout": 38, "pinned": 0, "total": 0 } }, "document": { "deleted": 21, "inserted": 78767, "returned": 103245, "updated": 1014 }, "getLastError": { "wtime": { "num": 0, "totalMillis": 0 }, "wtimeouts": 0 }, "operation": { "fastmod": 1, "idhack": 0, "scanAndOrder": 0 }, "queryExecutor": { "scanned": 0, "scannedObjects": 0 }, "record": { "moves": 0 }, "repl": { "apply": { "batches": { "num": 0, "totalMillis": 0 }, "ops": 0 }, "buffer": { "count": 0, "maxSizeBytes": 268435456, "sizeBytes": 0 }, "network": { "bytes": 0, "getmores": { "num": 0, "totalMillis": 0 }, "ops": 0, "readersCreated": 0 }, "preload": { "docs": { "num": 0, "totalMillis": 0 }, "indexes": { "num": 0, "totalMillis": 0 } } }, "storage": { "freelist": { "search": { "bucketExhausted": 0, "requests": 130732, "scanned": 231145 } } }, "ttl": { "deletedDocuments": 0, "passes": 11452 } },
    "ok": 1.0 }