[JAVA]日期比對 CompareTo

Date date1 = sdf.parse("2009-12-31");
Date date2 = sdf.parse("2010-01-31");
 
System.out.println(sdf.format(date1));
System.out.println(sdf.format(date2));
 
if(date1.compareTo(date2)>0){
   System.out.println("Date1 is after Date2");
}else if(date1.compareTo(date2)<0){
   System.out.println("Date1 is before Date2");
}else if(date1.compareTo(date2)==0){
   System.out.println("Date1 is equal to Date2");
}else{
   System.out.println("How to get here?");
}

http://www.mkyong.com/java/how-to-compare-dates-in-java/

[JSTL]判斷該欄位是否為空值

在JSTL裡，判斷欄位是否為空值

用 empty

ex: empty each.remCuser             判斷rmeCuser為空的
      not empty each.remCuser     判斷rmeCuser不為空的

[JAVA]比對Collection的值是否一樣

可以用containsKey去檢查map的key是否一樣
如此就不用一個一個去比對


http://www.roseindia.net/tutorial/java/core/hashMap/containsKey.html

HashMapContainsKey.java

package net.roseindia.java; import java.util.HashMap; public class HashMapContainsKey { public static void main(String[] arr) { /* Create object of HashMap */ HashMap<Integer, String> obMap = new HashMap<Integer, String>(); /* Add value in HashMap */ obMap.put(new Integer(1), "Bharat"); obMap.put(new Integer(2), "Gyan"); obMap.put(new Integer(4), "Vrishti"); obMap.put(new Integer(3), "Sarika"); obMap.put(new Integer(5), "Rohit"); obMap.put(new Integer(6), "Parineeta"); /* Check key present in HashMap or not */ System.out.println("Returns :" + obMap.containsKey(1)); System.out.println("Returns :" + obMap.containsKey(8)); } }

[jQuery] 取得被選取的 checkbox

$('input[name="firstname"]:checked').val();

http://blog.miniasp.com/post/2011/04/26/jQuery-get-form-value-Checkbox-Radio.aspx

[sql]DATE to Char

time zone

select to_char(sysdate, 'MON', 'NLS_DATE_LANGUAGE=american') from dual;


Reference:

http://sqle.ru/index.php/Oracle_PL/SQL/Date_Timezone/Date_Format#Change_the_original_date_format_in_the_TO_CHAR_function

http://www.toadworld.com/KNOWLEDGE/KnowledgeXpertforOracle/tabid/648/TopicID/SQL52F46/Default.aspx

http://gogates.blogspot.tw/2011/09/use-of-nlsdatelanguage-parameter-in.html

[SQL]將用分號將字串切割，並切換多行

select regexp_substr(mystring,'[^,]+',1,level) element
        from dual
     connect by level <= length(regexp_replace(mystring,'[^,]+')) + 1

Reference:
http://stackoverflow.com/questions/4004377/splitting-comma-separated-string-in-a-pl-sql-stored-proc

[SQL]反向查詢吃不到INDEX

剛剛在看文件的時候看到
select 的條件若有 <> 時會吃不到Index

另外也儘量不用 not in
可以用not exists or in ( select ... from table1 minus select ... from table2)

以上可以提升效能

http://stackoverflow.com/questions/3545323/why-the-select-from-table-where-id-not-in-list-of-int-ids-query-is-slow-in

[SQL]optimal not in performance

若使用not in 的效能很差
可以改用minus可以提升效能

http://dbaforums.org/oracle/index.php?showtopic=21583

http://www.dba-oracle.com/oracle_news/2005_3_31_tips_using_not_exists_minus_sql.htm

http://www.dba-oracle.com/t_cbo_existence_queries.htm

[JavaScrip]判斷字串是否為空白或包含某字元

判斷是否為空白字元
$('[name*=polFormatid]').val().trim() == ""
http://stackoverflow.com/questions/1151032/javascript-blank-space-validation


判斷是否包含某字元
$('[name*=polFormatid]').val().indexOf("%") != -1
http://stackoverflow.com/questions/1789945/method-like-string-contains-in-javascript http://miisoo.blogspot.tw/2008/01/javascript-string-operations.html

[SQL] new line sign

new line in plsql is  CHR(13) || CHR(10)

reference:http://www.orafaq.com/forum/t/59679/2/

[SQL]ROW LOCK的發生情況

1.UPDATE的時候會造成ROW LOCK

最好在UPDATE後COMMIT
開頭也要加 PRAGMA AUTONOMOUS_TRANSACTION

2.同時INSERT時也會LOCK

參考：
http://www.dbasky.com/oracle/update_index_row_lock_waits.html

[SQL]數值處理

ROUND(n, [m]) --四捨五入(m代表取到第幾位)

SELECT ROUND(5/3, 2) FROM DUAL;
=>1.67


SELECT ROUND(5/3, 0) FROM DUAL;
=>2



TRUNC(n, [m]) --無條件捨去(m代表取到第幾位)

SELECT TRUNC(5/3, 2) FROM DUAL;
=>1.66


SELECT TRUNC(5/3, 0) FROM DUAL;
=>1

[JAVA]POI Example

http://poi.apache.org/spreadsheet/quick-guide.html

http://www.blogjava.net/ltc603/archive/2006/08/16/63804.html

http://hypgr.iteye.com/blog/439820