Recent Notes
Displaying keyword search results 1 - 10
Created by Dr. Xi on June 22, 2011 13:23:19
Last update: April 30, 2012 11:40:06
This is a utility to convert a byte array to hex string, and to convert a hex string back to the original.
To convert a String to hex, you must call String.getBytes() first. The utility does not pretend to know your string encoding.
public class StringHexUtil {
public static ...
This also works:
String binaryToHex(byte[] data) {
StringBui...
Created by Dr. Xi on November 11, 2011 10:05:22
Last update: November 11, 2011 10:12:01
This is an HTML image tag filter using Java regex. It takes a string, finds the img tags, replaces the src attribute with one provided by the filter, then adds a class name to the class attribute.
import java.util.regex.*;
import java.io.*;
...
Test file:
<div id="HTML snippet">
<img src="img/big/txt-m...
Created by alfa on July 15, 2011 13:25:45
Last update: July 15, 2011 13:25:45
Read the whole contents of a file into a String. It's better to read the whole file as bytes and convert to String than to read the file line by line and concatenate the lines.
String getFileContents(String fileName) throws...
Using java.nio :
import java.io.FileInputStream;
import java...
Created by Dr. Xi on July 14, 2011 08:26:05
Last update: July 14, 2011 08:26:05
You can iterate through an array of String like this:
String[] a = { "one", "two", "three" };
for (in...
or like this:
for (String s: a) {
System.out.println(s);
...
For a string Collection , iterate like this:
Collection<String> c = Arrays.asList("one", "two",...
or like this:
Collection<String> c = Arrays.asList("one", "two",...
Created by Dr. Xi on September 04, 2008 18:34:25
Last update: July 14, 2011 07:31:48
The one argument version of String.split omits trailing empty strings. To get all parts, including trailing empty strings, you need to use the two argument version with a negative limit :
public class TestStringSplit {
public stati...
Output:
Length of array: 8
Part[0]: '1'
Part[1]: '2'...
Created by alfa on July 01, 2011 13:16:12
Last update: July 01, 2011 13:16:12
This is a simple doclet that prints all public methods and their parameter names and types.
Code
import com.sun.javadoc.*;
public class List...
Compile
javac -cp $JAVA_HOME/lib/tools.jar:. ListMethodsDo...
Use
javadoc -doclet ListMethodsDoclet -sourcepath /pat...
Created by Dr. Xi on June 22, 2011 15:15:15
Last update: June 22, 2011 15:15:15
There's no such thing as an immutable byte array in Java. What we are trying to achieve here is to protect the byte array inside the object from which it is being returned. We want to caller to have the contents of the byte array, but not be able to change the contents inside the object. The trick is to return a copy instead of the internal reference:
public class ReturnByteArray {
public stati...
Created by Dr. Xi on June 22, 2011 07:33:45
Last update: June 22, 2011 11:57:54
Demo code for CSV parsing with OpenCSV . Java code:
import java.io.*; import au.com.bytecode.opencs... Test with a simple CSV file: psmith01,CLASS2B,Peter Smith 1,YEAR2,1,N,ADVANCED,... The parser worked correctly: Line 1 has 11 values: |psmith01| |CLASS2B|... Test with a more complicated CSV file: "psmith01 abc", "CLASS2B " , " Peter... Result: Line 1 has 4 values: |psmith01 abc| |CLASS... The parser: Escaped quote and backslash correctly Ignored spaces before the quotation mark - sometimes (see below) Counted spaces after the right quotation mark till the comma as content, including the right quotation mark (bug). Ignored improperly quoted item - silently (third line) Indeed, the OpenCSV parser has a problem with spaces: Input: "Smith, Jack", "210-345-8888" "Smith, J... Result: Line 1 has 2 values: | Smith, Jack| |210-3......
Created by Dr. Xi on June 22, 2011 09:42:35
Last update: June 22, 2011 11:39:40
Demo code for CSV parsing with Skife CSV . Java code:
import java.io.*; import java.util.*; import... Test with a simple CSV file: psmith01,CLASS2B,Peter Smith 1,YEAR2,1,N,ADVANCED,... The parser worked correctly: Line 1 has 11 values: |psmith01| |CLASS2B|... Test with a more complicated CSV file: "psmith01 abc", "CLASS2B " , " Peter... Result: Line 1 has 4 values: |psmith01 abc| | CLAS... The parser worked correctly. But notice that it counts the spaces outside of the quotes significant, and doing so consistently. One more test for spaces: "Smith, Jack" , "210-345-8888" "Smith, Jack"... Result: Line 1 has 2 values: | Smith, Jack | | 210... Add a new line in item two: "One", "Two ", "Three" Result: Line 1 has 2 values: |One| | Two| L...
Created by Dr. Xi on June 21, 2011 15:41:51
Last update: June 22, 2011 11:33:36
Demo code for CSV parsing with Apache Commons CSV parser .
Java code:
import java.io.*;
import org.apache.commons.csv...
Test with a simple CSV file:
psmith01,CLASS2B,Peter Smith 1,YEAR2,1,N,ADVANCED,...
Result:
Line 1 has 11 values:
|psmith01|
|CLASS2B|...
The parser worked correctly.
Test with a more complicated CSV file:
"psmith01 abc", "CLASS2B " , " Peter...
Result:
Line 1 has 4 values:
|psmith01 abc|
|CLASS...
The third line is invalid input, but throwing a Java IOException is a bit grave. Also, the parser is not able to escape a backslash.
Add a new line in item two:
"One", "Two
", "Three"
Result:
Line 2 has 3 values:
|One|
|Two
|
|...
