If you need to search for a phrase or a string in a text file Java regular expression is the easiest way to accomplish this task. Here is a simple example that demonstrates how you can use Java regular expression to find a string or a phrase in a text file.

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.ArrayList;
import java.io.IOException;
public class TextSearch{
	public ArrayList searchString(String fileName,
                                            String phrase) throws IOException{
	  Scanner fileScanner = new Scanner(new File(fileName));
	  int lineID = 0;
	  ArrayList lineNumbers = new ArrayList();
	  Pattern pattern =  Pattern.compile(phrase);//,Pattern.CASE_INSENSITIVE);
	  Matcher matcher = null;
	  while(fileScanner.hasNextLine()){
			String line = fileScanner.nextLine();
			lineID++;
			matcher = pattern.matcher(line);
			if(matcher.find()){
				lineNumbers.add(lineID);

			}

		}
		return lineNumbers;
	}
}

Here in this example I read input file line by line searching for the given string or phrase. The code uses Pattern and Matcher classes to search for the string. If a line contains the string we are looking for we store its line number in an ArrayList. At the end, the method returns the ArrayList of Integer objects depicting the lines of the file that have the given string. If the file does not contain given string an appropriate message will be printed.

How to search for a string in a file using Java regular expression. is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha

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If you need to read properties file in your Spring application all you need is to configure a PropertyPlaceholderConfigurer bean in your application context.
Following example shows how to read property values from a properties file named config.properties. This file needs to be in your classpath so Spring can find it.

Let’s begin by creating a simple Java class that will use the properties values from the file.

package com.zparacha.spring.examples.config;

public class CreateUser {
	//Spring will populate these fields through Dependency Injection.
        private String name;
	private String email;
	private String URL;

	public CreateUser(){}
	public String getName() {
	  return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getEmail() {
		return email;
	}

	public void setEmail(String email) {
		this.email = email;
	}

	public String getURL() {
		return URL;
	}

	public void setURL(String url) {
		URL = url;
	}
	public void displayUser() {
		System.out.println("Name=" + this.name);
		System.out.println("Email="+ this.email);
		System.out.println("URL=" + this.URL);
	}
}

Now create the application context. I saved the file as user.xml

Notice the placeholderConfig bean. This is where we are instructing Spring container to load the values from config.properties file. You can name your will whatever you like.

Here is my config.properties file.

name=John Doe
URL=http://www.zparacha.com
email=demo@zparacha.com

That is all there is to read the properties file.
Following is a simple test client.

package com.zparacha.spring.examples.config;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class UserClient {
	public static void main(String[] args) throws Exception {
		String[] configFiles = new String[] { "user.xml" };
		BeanFactory factory =
			new ClassPathXmlApplicationContext (configFiles);
		CreateUser createUser =
	        (CreateUser) factory.getBean("createUser");
		createUser.displayUser();
	  }
}

If you execute this class it will print

Name=John Doe
Email=demo@zparacha.com
URL=http://www.zparacha.com

This approach to use PropertyPlaceholderConfigurer to read properties file will not work if you are using XmlBeanFactory. To read properties file with XmlBeanFactory you will have to retrieve the bean from context and invoke it on your factory.

For example:

package com.zparacha.spring.examples.config;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class UserClient2 {
	public static void main(String[] args) throws Exception {
		XmlBeanFactory factory =
			        new XmlBeanFactory(new ClassPathResource("hello.xml"));
			  PropertyPlaceholderConfigurer configurer = (PropertyPlaceholderConfigurer)factory.getBean("placeholderConfig");
	  configurer.postProcessBeanFactory(factory);
		CreateUser createUser =
	        (CreateUser) factory.getBean("createUser");
		createUser.displayUser();
	  }
}

Unless you have your reasons to use XmlBeanFactory, I would recommend that you use ClassPathXmlApplicationContext as your factory.

Enjoy.

How to read properties file in Spring. is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha

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Sometimes when you upload or FTP files from a Windows system to a UNIX box you will see ^M at the end of each line. ^M is the UNIX equivalent of DOS line break. Not only does it not look pretty, this extra character may break all sorts of scripts that you try to run on your file. So how do you remove ^M? Here are two ways to get rid or ^M (Ctrl-M) from your files.

Option 1.Use dos2unix utility. The easiest way is to use dos2unix utility.
dos2unix originalfile convertedfile.

You can run man dos2unix to learn about all the options.

Option 2. If you do not have dos2unix utility the next best option is to edit the file in VI. Open the file in VI editor and do a global search and replace.
:%s/(ctrl+V)(ctrl+M)//g and hit enter.

Be aware that ^M is not just a ^ followed by a M. You will have to press CTRL and V to get ^ and then CRTL and M to get the M.
After replacing ^M do :wq or ZZ to save and exit the VI editor.
Enjoy.

How to remove Ctrl-M (^M) from Unix files? is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha

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For PL/SQL developers put_line is a quite useful method. I use it for logging purposes. Recently I found out that the method has an annoying limitation. You cannot print more than 255 characters per line!
Now that is a strange feature. I don’t know what is the reasoning behind this restriction but it does make this method somewhat risky to use. Because if you use put_line to log a string more than 255 characters long it will raise an exception and you program might fail. Unless you catch the exception and continue on with your flow. Obviously no good programmer would want the trouble of adding exception handling code for such a mundane task as logging. So far I have not found an alternative method to print out large string in PL/SQL but I came up with a work around.
I created a little procedure to print large string.

Here is the method.

PROCEDURE print_line(p_str IN VARCHAR2) IS
l_offset NUMBER;
l_length NUMBER;
l_max_len NUMBER;
l_line VARCHAR2(256);
BEGIN
 l_offset :=1;
 l_max_len :=255;
 l_length:=LENGTH(p_str);
dbms_output.put_line(l_length);
 WHILE l_offset <= l_length LOOP
	   l_str := SUBSTR(p_str,  l_offset,
	                         l_max_len);
	   l_offset := l_offset+l_max_len;
      dbms_output.put_line(l_line);
    END LOOP;
 END;

Let's now write a simple test client to see this method in action.

DECLARE
l_str VARCHAR2(3000);
l_phrase VARCHAR2(300);
BEGIN
l_phrase :=' The quick brown fox jumps over the lazy dog';
--Create a string bigger than 255 characters.
FOR i IN 1..20 LOOP
 l_str := l_str || l_phrase;
END LOOP;
l_length:=LENGTH(l_str);
dbms_output.put_line(l_length); -- The string has 880 characters.
--dbms_output.put_line(l_str); //Cannot do this. You will get following error.
/*
ORA-20000: ORU-10028: line length overflow, limit of 255 chars per line
ORA-06512: at "SYS.DBMS_OUTPUT", line 35
ORA-06512: at "SYS.DBMS_OUTPUT", line 133
ORA-06512: at line 15
*/
 --Now try our method.
  print_line(l_str);
END;

Here is the output
/*
The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps over the
lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps
over the lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy dog The quick brown
fox jumps over the lazy dog The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy dog
*/

Feel free to copy, modify and use this method. If you know a better way of achieving this please let me know.

Print large string in PL/SQL. is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha

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