Exception Dart异常:类字符串没有实例方法'&燃气轮机';
我正在编写一个简单的类来使用sqljocky管理数据库查询。代码如下Exception Dart异常:类字符串没有实例方法'&燃气轮机';,exception,dart,sqljocky,Exception,Dart,Sqljocky,我正在编写一个简单的类来使用sqljocky管理数据库查询。代码如下 import'包:sqljocky/sqljocky.dart'; 导入'Config.dart'; 抽象类QueryResultCallBack{ void handleQuery(动态queryResult); } 类数据库工厂{ 静态数据库工厂实例; 静态DatabaseFactory getInstance(){ if(实例==null) 实例=新数据库工厂(); 返回实例; } var-dbpool; 数据库工厂()
import'包:sqljocky/sqljocky.dart';
导入'Config.dart';
抽象类QueryResultCallBack{
void handleQuery(动态queryResult);
}
类数据库工厂{
静态数据库工厂实例;
静态DatabaseFactory getInstance(){
if(实例==null)
实例=新数据库工厂();
返回实例;
}
var-dbpool;
数据库工厂(){
如果(Config.DB_PWD.length==0){
dbpool=newconnectionpool(主机:Config.DB\u主机,端口:Config.DB\u端口,用户:Config.DB\u用户,DB:Config.DB\u名称,最大:Config.DB\u连接\u池大小);
}否则{
dbpool=newconnectionpool(主机:Config.DB\u主机,端口:Config.DB\u端口,用户:Config.DB\u用户,密码:Config.DB\u PWD,DB:Config.DB\u名称,最大:Config.DB\u连接\u池大小);
}
}
void executelquery(字符串查询、QueryResultCallBack){
query(query).then((result){
callback.handleQuery(结果);
});
}
void executeQuery(字符串queryStr、列表参数、QueryResultCallBack){
试一试{
dbpool.prepareExecute(queryStr,params).then((结果){
callback.handleQuery(结果);
});
}捕获(e){
打印('DatabaseFactory.executeQuery异常:\n${e}');
}
}
无效关机(){
dbpool.close();
}
}
但是,当执行查询时,我会得到异常“class String has no instance method')。堆栈跟踪显示它在此处抛出:
dbpool.prepareExecute(queryStr, params).then((result) {
我在互联网上搜索过,大多数情况下都是这样的错误,就是在一个包中抛出了一个bug,但是没有发现任何发生在类字符串上的情况。有什么想法吗
提前谢谢
编辑:Stacktrace
Uncaught Error: Class 'String' has no instance method '>'.
NoSuchMethodError : method not found: '>'
Receiver: "5"
Arguments: [0]
Stack Trace:
#0 Object.noSuchMethod (dart:core-patch/object_patch.dart:45)
#1 int.< (dart:core-patch/integers.dart:72)
#2 ConnectionPool._getConnection (package:sqljocky/src/connection_pool.dart
:64:29)
#3 Query._getConnection (package:sqljocky/src/query.dart:35:32)
#4 Query._prepare (package:sqljocky/src/query.dart:41:26)
#5 ConnectionPool.prepare (package:sqljocky/src/connection_pool.dart:242:26
)
#6 ConnectionPool.prepareExecute (package:sqljocky/src/connection_pool.dart
:310:19)
#7 DatabaseFactory.executeQuery (file:///C:/Users/Nadir/Downloads/dart/dart
-sdk/bin/prueba/DatabaseFactory.dart:46:28)
#8 main.<anonymous closure>.<anonymous closure> (file:///C:/Users/Nadir/Dow
nloads/dart/dart-sdk/bin/prueba/Server.dart:27:49)
#9 _rootRunUnary (dart:async/zone.dart:717)
#10 _RootZone.runUnary (dart:async/zone.dart:854)
#11 _BaseZone.runUnaryGuarded (dart:async/zone.dart:569)
#12 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:333)
#13 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:263)
#14 _StreamController&&_SyncStreamControllerDispatch._sendData (dart:async/s
tream_controller.dart:529)
#15 _StreamController._add (dart:async/stream_controller.dart:438)
#16 _StreamController.add (dart:async/stream_controller.dart:395)
#17 _HttpServer._handleRequest (http_impl.dart:2116)
#18 _HttpConnection._HttpConnection.<anonymous closure> (http_impl.dart:1954
)
#19 _rootRunUnary (dart:async/zone.dart:717)
#20 _RootZone.runUnary (dart:async/zone.dart:854)
#21 _BaseZone.runUnaryGuarded (dart:async/zone.dart:569)
#22 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:333)
#23 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:263)
#24 _StreamController&&_SyncStreamControllerDispatch._sendData (dart:async/s
tream_controller.dart:529)
#25 _StreamController._add (dart:async/stream_controller.dart:438)
#26 _StreamController.add (dart:async/stream_controller.dart:395)
#27 _HttpParser._doParse (http_parser.dart:687)
#28 _HttpParser._parse (http_parser.dart:343)
#29 _onData (http_parser.dart:813)
#30 _rootRunUnary (dart:async/zone.dart:717)
#31 _RootZone.runUnary (dart:async/zone.dart:854)
#32 _BaseZone.runUnaryGuarded (dart:async/zone.dart:569)
#33 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:333)
#34 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:263)
#35 _StreamController&&_SyncStreamControllerDispatch._sendData (dart:async/s
tream_controller.dart:529)
#36 _StreamController._add (dart:async/stream_controller.dart:438)
#37 _StreamController.add (dart:async/stream_controller.dart:395)
#38 _onData (dart:io-patch/socket_patch.dart:1356)
#39 _rootRunUnary (dart:async/zone.dart:717)
#40 _RootZone.runUnary (dart:async/zone.dart:854)
#41 _BaseZone.runUnaryGuarded (dart:async/zone.dart:569)
#42 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:333)
#43 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:263)
#44 _StreamController&&_SyncStreamControllerDispatch._sendData (dart:async/s
tream_controller.dart:529)
#45 _StreamController._add (dart:async/stream_controller.dart:438)
#46 _StreamController.add (dart:async/stream_controller.dart:395)
#47 _RawSocket._RawSocket.<anonymous closure> (dart:io-patch/socket_patch.da
rt:948)
#48 multiplex (dart:io-patch/socket_patch.dart:604)
#49 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dar
t:115)
Unhandled exception:
Class 'String' has no instance method '>'.
NoSuchMethodError : method not found: '>'
Receiver: "5"
Arguments: [0]
#0 _rootHandleUncaughtError.<anonymous closure>.<anonymous closure> (dart:a
sync/zone.dart:700)
#1 _asyncRunCallbackLoop (dart:async/schedule_microtask.dart:23)
#2 _asyncRunCallback (dart:async/schedule_microtask.dart:32)
#3 _asyncRunCallback (dart:async/schedule_microtask.dart:36)
#4 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dar
t:119)
Uncaught错误:类“String”没有实例方法“>”。
NoSuchMethodError:找不到方法:'>'
接收者:“5”
参数:[0]
堆栈跟踪:
#0 Object.noSuchMethod(省道:核心补片/对象补片。省道:45)
#1整数<(省道:核心补片/整数。省道:72)
#2 ConnectionPool.\u getConnection(包:sqljocky/src/connection\u pool.dart
:64:29)
#3 Query.\u getConnection(包:sqljocky/src/Query.dart:35:32)
#4查询.\u准备(包:sqljocky/src/Query.dart:41:26)
#5 ConnectionPool.prepare(包:sqljocky/src/connection\u pool.dart:242:26
)
#6 ConnectionPool.prepareExecute(包:sqljocky/src/connection\u pool.dart
:310:19)
#7 DatabaseFactory.executeQuery(file:///C:/Users/Nadir/Downloads/dart/dart
-sdk/bin/prueba/DatabaseFactory.dart:46:28)
#8主要(file:///C:/Users/Nadir/Dow
nloads/dart/dart sdk/bin/prueba/Server.dart:27:49)
#9_rootrunnary(dart:async/zone.dart:717)
#10_RootZone.runUnary(dart:async/zone.dart:854)
#11_BaseZone.runUnaryGuarded(dart:async/zone.dart:569)
#12 _BufferingStreamSubscription._sendData(dart:async/stream\u impl.dart:333)
#13 _BufferingStreamSubscription._add(dart:async/stream\u impl.dart:263)
#14 \u StreamController和\u SyncStreamControllerDispatch.\u发送数据(dart:async/s
(飞镖手:529)
#15\u StreamController.\u add(dart:async/stream\u controller.dart:438)
#16\u StreamController.add(dart:async/stream\u controller.dart:395)
#17_HttpServer._handleRequest(http_impl.dart:2116)
#18_HttpConnection._HttpConnection.(http_impl.dart:1954)
)
#19_rootrunnary(dart:async/zone.dart:717)
#20_RootZone.runUnary(dart:async/zone.dart:854)
#21_BaseZone.runUnaryGuarded(dart:async/zone.dart:569)
#22 _BufferingStreamSubscription._sendData(dart:async/stream\u impl.dart:333)
#23 _BufferingStreamSubscription._add(dart:async/stream\u impl.dart:263)
#24(数据流控制器&)同步数据流控制器发送数据(dart:async/s)
(飞镖手:529)
#25\u StreamController.\u add(dart:async/stream\u controller.dart:438)
#26_StreamController.add(dart:async/stream_controller.dart:395)
#27_HttpParser._doParse(http_parser.dart:687)
#28_HttpParser._parse(http_parser.dart:343)
#29_onData(http_parser.dart:813)
#30_rootrunnary(dart:async/zone.dart:717)
#31_RootZone.runUnary(dart:async/zone.dart:854)
#32_BaseZone.runUnaryGuarded(dart:async/zone.dart:569)
#33 _BufferingStreamSubscription._sendData(dart:async/stream\u impl.dart:333)
#34 _BufferingStreamSubscription._add(dart:async/stream\u impl.dart:263)
#35_StreamController&&u SyncStreamControllerDispatch._sendData(dart:async/s
(飞镖手:529)
#36\u StreamController.\u add(dart:async/stream\u controller.dart:438)
#37_StreamController.add(dart:async/stream_controller.dart:395)
#38_onData(dart:io补丁/插座补丁。dart:1356)
#39_rootrunnary(dart:async/zone.dart:717)
#40_RootZone.runUnary(dart:async/zone.dart:854)
#41_BaseZone.runUnaryGuarded(dart:async/zone.dart:569)
#42 _BufferingStreamSubscription._sendData(dart:async/stream\u impl.dart:333)
#43 _BufferingStreamSubscription._add(dart:async/stream\u impl.dart:263)
#44 \u StreamController和\u SyncStreamControllerDispatch.\u发送数据(dart:async/s
(飞镖手:529)
#45_StreamController._add(dart:async/stream_controller.dart:438)
#46_StreamController.add(dart:async/stream_controller.dart:395)
#47_RawSocket._RawSocket.(省道:io补丁/socket_patch.da)
rt:948)
#48多路复用(dart:io补丁/插座补丁。dart:604)
#49 _RawReceivePortImpl._handleMessage(dart:隔离补丁/隔离补丁.dar
t:115)
未处理的异常:
类“String”没有实例方法“>”。
NoSuchMethodError:找不到方法:'>'
接收者:“5”
参数:[0]
#0_roothandleuncaughtror..(省道:a)
同步/分区。省道:700)
#1\u asyncRunCallbackLoop(dart:async/schedule\u microtask.dart:23)
#2\u asyncRunCallback(dart:async/schedule\u microtask.dart:32)
#3\u asyncRunCallback(dart:async/schedule\u microtask.dart:36)
#4 _RawReceivePortImpl._handleMessage(dart:isolate patch/isolate_patch.dar
T