Spring-03-Setter Injection and IoC

Understanding WSDL

This is an attempt to explain WSDL in the simplest manner

About WSDL

•WSDL stands for Web Service Definition Language.
•It is a contract to the web service that is expressed in XML. To understand better this can be compared to an Interface in Java or a Package in Oracle which acts as a contract between the client and the system.
Structure of WSDL (parallels are drawn to Java wherever possible)

1.What are the capabilities of the Service?
◦What are the operations(methods) provided by the Service and what are the messages(parameters) that each operation requires?
◦The messages can be input(parameters), output(return value) or faults(exception)
2.How can the Service be accessed?
◦What is the protocol(SOAP) and what is the encoding(document)?
3.Where can the Service be accessed?
◦What is the endpoint(address) of the Service?

Top Down Vs Bottom Up Approach

Context "Whether I should start Developing JSP first or the Business Logic ?" is a common question that arises to every developer. This blog talks about the same and try to see the advantage & Disadvantage of both approaches. Top Down Approach What is Top Down Approach? Top Down approach is to start implementing Presentation Layer and then implement the Business Logic. Advantage: • Easy to visualize functionality. • Sense of completeness in the requirement. • Easy to show the progress of development. Disadvantage: • UI driven approach hence high possibility of redundant business logics. • Since an UI is readily available no developer would write a Unit test cases. • No Concrete layer to rely on, as both presentation & Business Logic keep evolving. • Lack of concrete test suits to ensure one layer is tied up. Bottom Up Approach What is Bottom Up Approach? Bottom Up approach is to start with the concrete business logic and its testcase and proceed with presentation Implementation. Advantage: • Solid Business Logic, hence zero redundancy • Good Unit test case can be written to validate changes. • Developer has only option to use unit testing tools to test the Logic. • Easy to manage changes and modification. Disadvantage: • Effort involved to write test cases. • Progress of implementation cannot be show very effectively. Conclusion As the number of tier & layers getting more and more, the amount complexity due to loose coupling also increases. Business logic is one which need to be concrete, testable and manageable. There is no right or wrong in these approaches, but business logic is heart of any modern day or traditional applications. If one has a concrete business logic, it's easy to provide a UI to manipulate the same (UI Developer's excuse me for that, this my perspective). Note: I prefer the Bottom Up approach, and i feel lot more comfortable and confident that my one end it tied up, and i need not worry about it.

Simple JDBC Program to Access/Read Microsoft Excel

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class Main {

public static Connection getConnection() throws Exception {
String driver = "sun.jdbc.odbc.JdbcOdbcDriver";
String url = "jdbc:odbc:excelDB";
String username = "yourName";
String password = "yourPass";
Class.forName(driver);
return DriverManager.getConnection(url, username, password);
}

public static void main(String args[]) throws Exception {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;

conn = getConnection();
stmt = conn.createStatement();
String excelQuery = "select * from [Sheet1$]";
rs = stmt.executeQuery(excelQuery);

while (rs.next()) {
System.out.println(rs.getString("FirstName") + " " + rs.getString("LastName"));
}

rs.close();
stmt.close();
conn.close();
}
}

Read and Write Microsoft Excel ( .xls ) Documents with Jakarta's POI Open source

Reading an Excel Document
Reading an existing Excel document is just as simple as creating one. HSSF provides a custom POIFSFileSystem object that specializes in reading Microsoft's OLE 2 documents. Using the POIFSFileSystem object, you construct an HSSFWorkbook object from a specified Excel document. Here's an example.


//create a POIFSFileSystem object to read the data
POIFSFileSystem fs = new POIFSFileSystem(
new FileInputStream(
"c:/dev/src/customs/Book1.xls"));
Next, create a new workbook from the input stream. You can obtain a reference to any of the worksheets within the workbook. Notice that the worksheet index starts at 0.


// create a workbook out of the input stream
HSSFWorkbook wb = new HSSFWorkbook(fs);
// get a reference to the worksheet
HSSFSheet sheet = wb.getSheetAt(0);
A Little Bit More
Some of you may need to use Java to access Excel from a Web application. In such cases, you may need to construct an Excel document and show it in a browser. That's not difficult but does require a little trick. You send the Excel document as the response, but to make it appear in Excel, you need to set the MIME type of the response to the appropriate type. This method is browser independent. Here's an example:


try {
OutputStream out = res.getOutputStream();

// SET THE MIME TYPE
res.setContentType("application/vnd.ms-excel");

// set content dispostion to attachment in
// case the open/save dialog needs to appear
res.setHeader("Content-disposition",
"inline; filename=sample");
workBook.write(out);
out.flush();
out.close();
} catch (FileNotFoundException fne) {
System.out.println("File not found...");
} catch (IOException ioe) {
System.out.println("IOException..." +
ioe.toString());
}
The following points are important:


Use the MIME type string "application/vnd.ms-excel"
In the response header, the content-disposition entry defines how to deliver this content to the browser. For example, an inline attribute specifies that the browser should present an Open/Save/Cancel dialog before opening this document. The filename attribute specifies a default file name for the document.
This tutorial should help you to get started in the world of Java-to-Microsoft bridges. The POI project offers considerably more than I've discussed here, such as the capability to interact with Microsoft Word and with Adobe's PDF files. The project is very active, so you should monitor the POI project and keep up what's going on.

Q : How to read a Microsoft Excel ( .xls ) file from Java?

June 29, 2001

Can I read a Microsoft Excel file from Java? If so, how?

Yes, you can read Microsoft Excel files from Java. Microsoft provides an ODBC driver for Excel, thus allowing you to use JDBC
and the Sun JDBC-ODBC driver to read Excel files.

Assume you have an Excel file named c:\qa.xls . Also suppose that the data is in a worksheet named qas and takes the following excel/04-qa-0629-excel-table.html Following format .

Microsoft's ODBC driver treats the first row in a spreadsheet as the column names and the worksheet name as the database
name.

To access a spreadsheet with JDBC, you need to create a new ODBC data source. To create one in Windows 2000:

1. Go to "Control Panel"


2. Go to "Administrative Tools"


3. Go to "Data Sources"


4. Select "Add"


5. Choose "Microsoft Excel Driver" and "Finish," as seen in Figure 1

Figure 1. Create new data source

Then give the "Data Source Name" qa-list and select the workbook, shown in Figure 2.

Figure 2. ODBC Microsoft Excel Setup

When you are done you should see your new qa-list data source name:

Figure 3. New listing of user data sources

Now the spreadsheet is available as an ODBC source.

Say that you would like to pull out all March 2000 entries. You will need to hit the data source with the following SQL query:

select URL from [qas$] where Month='March' and Year=2000;

Note that the table name is the name of the worksheet with a $ appended to the end. You have to append the $ in order for the query to work. Why? Because. The brackets are there because $ is a reserved character in SQL. Life is never easy.

Now try ExcelReader on for size:

import java.sql.Connection;

import java.sql.Statement;

import java.sql.ResultSet;

import java.sql.DriverManager;

public class ExcelReader 

{

    public static void main( String [] args )

    {

        Connection c = null;

        Statement stmnt = null;

        try

        {

            Class.forName( "sun.jdbc.odbc.JdbcOdbcDriver" );

            c = DriverManager.getConnection( "jdbc:odbc:qa-list", "", "" );

            stmnt = c.createStatement();

            String query = "select URL from [qas$] where Month='March' and Year=2000;";

            ResultSet rs = stmnt.executeQuery( query );

            

            System.out.println( "Found the following URLs for March 2000:" );

            while( rs.next() )

            {

                System.out.println( rs.getString( "URL" ) );

            }

        }

        catch( Exception e )

        {

            System.err.println( e );

        }

        finally

        {

            try

            {

                stmnt.close();

                c.close();

            }

            catch( Exception e )

            {

                System.err.println( e );

            }

        }

    }

}

In ExcelReader, the main() gets a connection to the spreadsheet, then pulls out all of the entries for March 2000.

10- 20 C questions

11. main()
{
char string[]="Hello World";
display(string);
}
void display(char *string)
{
printf("%s",string);
}
Answer:
Compiler Error : Type mismatch in redeclaration of function display
Explanation :
In third line, when the function display is encountered, the
compiler doesn't know anything about the function display. It assumes the
arguments and return types to be integers, (which is the default type). When it
sees the actual function display, the arguments and type contradicts with what it
has assumed previously. Hence a compile time error occurs.
12. main()
{
int c=- -2;
printf("c=%d",c);
}
Answer:
c=2;
Explanation:
Here unary minus (or negation) operator is used twice. Same
maths rules applies, ie. minus * minus= plus.
Note:
However you cannot give like --2. Because -- operator can only be
applied to variables as a decrement operator (eg., i--). 2 is a constant and not a
variable.
13. #define int char
main()
{
int i=65;
printf("sizeof(i)=%d",sizeof(i));

}
Answer:
sizeof(i)=1
Explanation:
Since the #define replaces the string int by the macro char
14. main()
{
int i=10;
i=!i>14;
Printf ("i=%d",i);
}
Answer:
i=0
Explanation:
In the expression !i>14 , NOT (!) operator has more precedence
than ‘ >’ symbol. ! is a unary logical operator. !i (!10) is 0 (not of true is false).
0>14 is false (zero).
15. #include
main()
{
char s[]={'a','b','c','\n','c','\0'};
char *p,*str,*str1;
p=&s[3];
str=p;
str1=s;
printf("%d",++*p + ++*str1-32);
}
Answer:
77
Explanation:
p is pointing to character '\n'. str1 is pointing to character 'a' ++*p. "p is
pointing to '\n' and that is incremented by one." the ASCII value of '\n' is 10,
which is then incremented to 11. The value of ++*p is 11. ++*str1, str1 is
pointing to 'a' that is incremented by 1 and it becomes 'b'. ASCII value of 'b' is
98.
Now performing (11 + 98 – 32), we get 77("M");
So we get the output 77 :: "M" (Ascii is 77).
16. #include
main()
{
int a[2][2][2] = { {10,2,3,4}, {5,6,7,8} };
int *p,*q;
p=&a[2][2][2];
*q=***a;
printf("%d----%d",*p,*q);
}
Answer:
SomeGarbageValue---1
Explanation:
p=&a[2][2][2] you declare only two 2D arrays, but you are trying
to access the third 2D(which you are not declared) it will print garbage values.
*q=***a starting address of a is assigned integer pointer. Now q is pointing to
starting address of a. If you print *q, it will print first element of 3D array.
17. #include
main()
{
struct xx
{
int x=3;
char name[]="hello";
};
struct xx *s;
printf("%d",s->x);
printf("%s",s->name);
}
Answer:
Compiler Error
Explanation:
You should not initialize variables in declaration
18. #include
main()
{
struct xx
{
int x;
struct yy
{
char s;
struct xx *p;
};
struct yy *q;
};
}
Answer:
Compiler Error
Explanation:
The structure yy is nested within structure xx. Hence, the elements
are of yy are to be accessed through the instance of structure xx, which needs an
instance of yy to be known. If the instance is created after defining the structure
the compiler will not know about the instance relative to xx. Hence for nested
structure yy you have to declare member.
19. main()
{
printf("\nab");
printf("\bsi");
printf("\rha");
}
Answer:
hai
Explanation:
\n - newline
\b - backspace
\r - linefeed
20. main()
{
int i=5;
printf("%d%d%d%d%d%d",i++,i--,++i,--i,i);
}
Answer:
45545
Explanation:
The arguments in a function call are pushed into the stack from left
to right. The evaluation is by popping out from the stack. and the evaluation is
from right to left, hence the result.
21. #define square(x) x*x
main()
{
int i;
i = 64/square(4);
printf("%d",i);
}
Answer:
64
Explanation:
the macro call square(4) will substituted by 4*4 so the expression
becomes i = 64/4*4 . Since / and * has equal priority the expression will be
evaluated as (64/4)*4 i.e. 16*4 = 64
22. main()
{
char *p="hai friends",*p1;
p1=p;
while(*p!='\0') ++*p++;
printf("%s %s",p,p1);
}
Answer:
ibj!gsjfoet
Explanation:
++*p++ will be parse in the given order

*p that is value at the location currently pointed by p will be taken

++*p the retrieved value will be incremented

when ; is encountered the location will be incremented that is p++ will be
executed
Hence, in the while loop initial value pointed by p is ‘h’, which is changed to ‘i’ by
executing ++*p and pointer moves to point, ‘a’ which is similarly changed to ‘b’
and so on. Similarly blank space is converted to ‘!’. Thus, we obtain value in p
becomes “ibj!gsjfoet” and since p reaches ‘\0’ and p1 points to p thus p1doesnot
print anything.