使用Nutz版本1.r.55
jdk版本 1.8
List list = sql.getList(Lesson.class); 这一句能够取得内容
但一for循环 就报错（如图二）
图一
图二
6 回复
java.lang.ClassCastException: org.nutz.dao.entity.Record cannot be cast to com.teachart.domain.Lesson
at com.teachart.services.lesson.impl.LessonServiceImpl.getPages(LessonServiceImpl.java:149)
at admin.teachart.controllers.lesson.LessonController.list(LessonController.java:114)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.nutz.mvc.impl.processor.MethodInvokeProcessor.process(MethodInvokeProcessor.java:25)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.AdaptorProcessor.process(AdaptorProcessor.java:33)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.ActionFiltersProcessor.process(ActionFiltersProcessor.java:58)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.ModuleProcessor.process(ModuleProcessor.java:123)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.EncodingProcessor.process(EncodingProcessor.java:27)
at org.nutz.mvc.impl.processor.AbstractProcessor.doNext(AbstractProcessor.java:44)
at org.nutz.mvc.impl.processor.UpdateRequestAttributesProcessor.process(UpdateRequestAttributesProcessor.java:15)
at org.nutz.mvc.impl.NutActionChain.doChain(NutActionChain.java:44)
at org.nutz.mvc.impl.ActionInvoker.invoke(ActionInvoker.java:67)
at org.nutz.mvc.ActionHandler.handle(ActionHandler.java:31)
at org.nutz.mvc.NutFilter.doFilter(NutFilter.java:196)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1099)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2508)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2497)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
public QueryResult getPages(String where, int pageNumber) {
try {
//定义分页
if (pageNumber == 0) {
pageNumber = 1;
}
//返回list
List<Lesson> lessons = new ArrayList<Lesson>();
Pager pager = this.dao().createPager(pageNumber, this.getPageSize());
//调用sql 回调查询
Sql sql = Sqls.queryRecord("select * from lesson " + where +
"limit " + (pageNumber - 1) * this.getPageSize() + " ," + pageNumber * this.getPageSize() + ";"
);
this.dao().execute(sql);
List<Lesson> list = sql.getList(Lesson.class);
if (!list.isEmpty()) {
//遍历报异常
for (Lesson l : list) {
System.out.println(l.getId());
}
}
for (Lesson lesson : sql.getList(Lesson.class)) {
//Lesson l = this.getLessonAllInfo(lesson.getId());
//lessons.add(l);
}
list = null;
Sql countSql = Sqls.fetchInt("select count(1) from lesson " + where);// 带count的sql
countSql.params().putAll(sql.params()); // 重用参数
this.dao().execute(countSql);
int count = countSql.getInt();
//封装QueryResult对象
pager.setRecordCount(count);
return new QueryResult(lessons, pager);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
这代码看的得有点崩溃
不要手工拼条件,用Cnd来拼
不要手工分页,除非内置的分页会报错
给你点范例, 自行改一下, 完全不需要自定义SQL啊
public QueryResult query(Cnd cnd, int pageNumber) {
QueryResult qr = new QueryResult();
Pager pager = new Pager().setPageNumber(pageNumber);
qr.setList(dao.query(Lesson.class, cnd, pager));
pager.setRecordCount(dao.count(Lesson.class, cnd));
qr.setPager(pager);
return qr;
}
另外,之所以报错,是因为 Sqls.queryRecord 返回的结果集就是List<Record>, 应该用Sqls.queryEntity
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