在java,commons beanutils中,尝试将属性'address'和'creditCardList'设置为object,但它给了我错误:
java.lang.NoSuchMethodException: Property 'address' has no setter method in class 'class com.dao.Student'
但我有这种方法.代码在这里:
public class Main {
public static void main(String[] args) {
Object student = new Student("John");
Object address = new Address("NJ");
try {
PropertyUtils.setProperty(student, "address", address);
//----------
List list = new ArrayList();
Object creditCard = new CreditCard();
list.add(creditCard);
PropertyUtils.setProperty(student, "creditCardList", list);
} catch (Exception e) {
e.printStackTrace();
}
}
}
class Student {
private String name;
private Address address;
private List<CreditCard> creditCardList;
public Student(String name) {
super(); …在Perl OOP中,如何转储此类及其父类中的所有方法/字段.
my ($self) = @_;
我看到了很多上面的构造函数.那么,是什么@_？
我有Java/OOP背景.如果您的解释可以遵循Java域,那么我将更容易理解.
在Oracle中,如果列类型是datetime,如何进行此日期比较？我想保持字符串格式'MM/dd/yyyy'.
这该怎么做 ？
谢谢
select * from my_tbl
where mycol >= '07/11/2012'
在C#中,我正在从字符串中解析日期,但它给了我错误
DateTime.Parse("07/26/2012");
错误
System.FormatException: String was not recognized as a valid DateTime.
at System.DateTimeParse.Parse(String s, DateTimeFormatInfo dtfi, DateTimeStyles styles)
at System.DateTime.Parse(String s)
它与日期格式有关吗？它与我的电脑设置有关吗？
谢谢
在java JPA中,如果我们需要创建一个映射到数据库的实体,我们只需使用注释@entity,它几乎是无代码的.在C#/ NHibernate中,我们有类似的吗？
谢谢
在GridView中,为什么我必须在同一页面而不是C#文件中定义select方法？
例如,在index.aspx中,我有
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="index.aspx.cs" Inherits="GridViewApp.index" %>
<asp:GridView ID="GridView1" runat="server"
onselectedindexchanged="GridView1_SelectedIndexChanged"
DataSourceID="SqlDataSource2" AllowPaging="True" AllowSorting="True">
<Columns>
<asp:CommandField ShowSelectButton="True" />
</Columns>
</asp:GridView>
GridView1_SelectedIndexChanged,这个方法必须在index.aspx而不是index.aspx.cs中定义？
错误消息是
Compiler Error Message: CS1061: 'ASP.index_aspx' does not contain a definition for 'GridView1_SelectedIndexChanged' and no extension method 'GridView1_SelectedIndexChanged' accepting a first argument of type 'ASP.index_aspx' could be found (are you missing a using directive or an assembly reference?)
更新:解决.在我清理项目后,重建它.它现在有效.构建/调试项目的正确方法是什么？如何清理缓存？
感谢您的帮助.
在SQLplus中,为什么我将行大小设置为max(32767),它仍然没有格式化.怎么解决？
select * from user_tables
TABLE_NAME TABLESPACE_NAME CLUSTER_NAME IOT_NAME STATUS PCT_FREE PCT_U
_TRANS MAX_TRANS INITIAL_EXTENT NEXT_EXTENT MIN_EXTENTS MAX_EXTENTS PCT_INCREASE FREELISTS FREELIST_GROUPS LOG B NUM_ROWS BLOCKS EMPTY_BLOCKS A
CHAIN_CNT AVG_ROW_LEN AVG_SPACE_FREELIST_BLOCKS NUM_FREELIST_BLOCKS DEGREE INSTANCES CACHE TABLE_LO SAMPLE_SIZE LAST_ANAL PAR IOT_TYPE T S NE
_ ROW_MOVE GLO USE DURATION SKIP_COR MON CLUSTER_OWNER DEPENDEN COMPRESS COMPRESS_FOR DRO REA
我正在使用SQL Developer来调试下面的代码,只有在完成所有存储过程后,输出结果才会显示在调试对话框中.我需要打开一些配置吗？
谢谢
FOR j IN REVERSE 1..i LOOP
DBMS_OUTPUT.PUT_LINE(emp_tab(j).first_name);
END LOOP;
日志
Connecting to the database hr.
Executing PL/SQL: ALTER SESSION SET PLSQL_DEBUG=TRUE
Executing PL/SQL: CALL DBMS_DEBUG_JDWP.CONNECT_TCP( '192.168.1.4', '53475' )
Debugger accepted connection from database on port 53475.
Source breakpoint occurred at line 24 of EMP_LIST.pls.
Source breakpoint occurred at line 24 of EMP_LIST.pls.
Source breakpoint occurred at line 24 of EMP_LIST.pls.
Source breakpoint occurred at line 24 of EMP_LIST.pls.
Source breakpoint occurred at line 24 of EMP_LIST.pls.
Source …在 perl 中，如何编写这个正则表达式？
my $line = "job_name_1_" ; #end with '_'
$pattern = "_$"; # tried "\_$", still doesn't work
if($line =~ m/$pattern/){
# remove last "_" ?
}
-#output should be "job_name"
这该怎么做 ？
我正在学习Oracle Lock.
在一个会话中
lock table countries in ROW Exclusive mode nowait;
在另一个会话中,我更新了县表.
SQL> update countries set country_name = 'ddd';
25 rows updated.
我期望会话将挂起.你知道为什么吗 ？
我检查EM,我确实看到了锁.