1,jsp的9大內置對象java
request,response,session,application,page,pageContext,out,config,exceptionsql
查過資料了,如今補充一下;數組
JSP中九大內置對象爲:
request 請求對象 類型 javax.servlet.ServletRequest 做用域 Request
response 響應對象 類型 javax.servlet.SrvletResponse 做用域 Page
pageContext 頁面上下文對象 類型 javax.servlet.jsp.PageContext 做用域 Page
session 會話對象 類型 javax.servlet.http.HttpSession 做用域 Session
application 應用程序對象 類型 javax.servlet.ServletContext 做用域 Application
out 輸出對象 類型 javax.servlet.jsp.JspWriter 做用域 Page
config 配置對象 類型 javax.servlet.ServletConfig 做用域 Page
page 頁面對象 類型 javax.lang.Object 做用域 Page
exception 例外對象 類型 javax.lang.Throwable 做用域 pagesession
2,哪一個標籤點擊文字會聚焦到text文本輸入框,答案是<input type="text" id="text1"><label for="text1">text1</label>app
3,輸出乘法口訣jsp
public static void pringChengfakoujue()
{ide
System.out.println("乘法口訣表");this
for(int outNum=1;outNum<=9;outNum++)
{
for(int innerNum=1;innerNum<=9;innerNum++)
{3d
if(outNum>=innerNum)
{
System.out.print("[" + innerNum + "*" + outNum + "=" + (outNum * innerNum) + "]");
}對象
}
System.out.println();
}
}
4,用數組實現一個棧,接口以下:
public interface IStatck {
Object pop();
int size();
void push(Object obj);
}
實現代碼:
package org.tws;
/**
* Created with IntelliJ IDEA.
* User: cutter.li
* Date: 14-3-4
* Time: 下午4:25
* To change this template use File | Settings | File Templates.
*/
public class ArrayStack implements IStatck {
private Object[] objArray;
public ArrayStack(Object[] objArray)
{
this.objArray=objArray;
}
@Override
public Object pop() {
if(null==objArray){
return null;
}
return objArray[objArray.length-1];
}
@Override
public int size() {
if(null==objArray) {
return 0;
}
return objArray.length;
}
@Override
public void push(Object obj) {
int length=size();
if(length==0)
{
objArray=new Object[]{obj};
} else
{
Object[] objArray2=new Object[length+1];
System.arraycopy(objArray,0,objArray2,0,length-1);
objArray2[length]=obj;
objArray=objArray2;
}
}
}
5,sql的行列轉換
select departmentname as '部門'
, sum(if(monthName=1,icome,0)) as '一月份'
, sum(if(monthName=2,icome,0)) as '二月份'
, sum(if(monthName=3,icome,0)) as '三月份'
, sum(icome) as '總收入'
from t_icome group by departmentName ;
數據準備:
CREATE TABLE `t_icome` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`departmentName` varchar(3) NOT NULL,
`monthName` int(11) NOT NULL,
`icome` float NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB;
INSERT INTO `t_icome` VALUES ('1', 'a', '1', '2000');
INSERT INTO `t_icome` VALUES ('2', 'a', '2', '2500');
INSERT INTO `t_icome` VALUES ('3', 'b', '1', '2500');
INSERT INTO `t_icome` VALUES ('4', 'b', '2', '2600');
INSERT INTO `t_icome` VALUES ('5', 'a', '3', '2600');
INSERT INTO `t_icome` VALUES ('6', 'b', '3', '2900');
INSERT INTO `t_icome` VALUES ('7', 'c', '1', '2900');
INSERT INTO `t_icome` VALUES ('8', 'c', '2', '2900');
6,數據去重
兩張結構相同的表,查找在表a中不在表b的數據;
數據和表:
DROP TABLE IF EXISTS `t_a`;
CREATE TABLE `t_a` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`no` varchar(20) DEFAULT NULL,
`product` varchar(20) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1;
INSERT INTO `t_a` VALUES ('1', 'aaa', 'xxx');
INSERT INTO `t_a` VALUES ('2', 'bbb', 'xyz');
INSERT INTO `t_a` VALUES ('3', 'aaa', 'aaa');
INSERT INTO `t_a` VALUES ('4', 'aaa', 'ddd');
DROP TABLE IF EXISTS `t_b`;
CREATE TABLE `t_b` (
`id` int(11) NOT NULL DEFAULT '0',
`no` varchar(20) DEFAULT NULL,
`product` varchar(20) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO `t_b` VALUES ('1', 'aaa', 'xyz');
INSERT INTO `t_b` VALUES ('2', 'aaa', 'aaa');
INSERT INTO `t_b` VALUES ('3', 'aaa', 'fuck');
INSERT INTO `t_b` VALUES ('4', 'bbb', 'ccc');
INSERT INTO `t_b` VALUES ('5', 'bbb', 'nimei');
sql寫法:
SELECT a.* FROM
t_a a
LEFT JOIN
t_b b ON a.no = b.no and a.product=b.product
WHERE b.no IS NULL and b.product is null;