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Showing posts from November, 2012

JAXB marshall and unmarshall

write xsd schema file(s) use xjc tool to compile xsd schema file(s) into java classes create a java object marshall the object into a file unmarshall the object from a file 1. drink.xsd schema file <xs:element name="drink"> <xs:complexType> <xs:sequence> <xs:element name="name" type="xs:string" /> <xs:element name="alcohol" type="AlcoholEnum" minOccurs="0" maxOccurs="10" /> <xs:element name="ice" type="xs:boolean" /> </xs:sequence> </xs:complexType> </xs:element> <xs:simpleType name="AlcoholEnum"> <xs:restriction base="xs:string"> <xs:enumeration value="vodka" /> <xs:enumeration value="rum" /> <xs:enumeration value="whiskey" /> <xs:enume

Java read file (entire or line by line)

Four ways to read a file in java. I have tested an execution time of them using 1,37 MB text file with 108825 lines. Result of tests is in a first comment of each method and is specified in milliseconds. 1 Read entire file at once 1.1 FileInputStream with read() // execution time: 7 - 8 ms ByteArrayOutputStream buffer = new ByteArrayOutputStream(); File file = new File("C:\\test.txt"); InputStream is = new FileInputStream(file); byte[] temp = new byte[1024]; int read; while ((read = is.read(temp)) >= 0) { buffer.write(temp, 0, read); } byte[] data = buffer.toByteArray(); System.out.println(new String(data)); PS: remember that read(byte[] b) doesn't do what you think it does -> link 1.2 FileInputStream with readFully() // execution time: 11 - 12 ms File file = new File("C:\\test.txt"); DataInput input = new DataInputStream(new FileInputStream(file)); byte[] bufferArray = new byte[(int) file.length()]; input.readFully(bufferArray); String value = new

scala Hello World

The code below prints Hello World! Hello.scala file (a name of file doesn't matter) object HelloWorld { def main(args: Array[String]) { println("Hello World!") } } Key word object is used to create a singleton object. To run this script use scala interpretor (check scala command line tools ).

scala command line tools

scalac scala compiler // compile a file scalac filename.scala fsc fast scala compiler (scala daemon for faster compiling) // start scala daemon and compile a file fsc filname.scala // stop scala deamon fsc -shutdown scala scala interpreter // run interpreter scala filename.scala

Logger java

Logger class import java.io.IOException; import java.util.logging.FileHandler; import java.util.logging.Formatter; import java.util.logging.Handler; import java.util.logging.Level; import java.util.logging.Logger; import java.util.logging.SimpleFormatter; public class TestLogger { public static void main(String args[]) { try { // 2012-11-08 10:01:32 TestLogger main\nWARNING: Some problem Formatter formatter = new SimpleFormatter(); // 2012-11-08 10:14:42 WARNING: TestLogger.main Some problem // Formatter formatter = new MyFormatter(); // boolean flag specifies append mode Handler handler = new FileHandler("MyLogFile.log", true); handler.setFormatter(formatter); Logger logger = Logger.getLogger("MyLoggerName"); logger.addHandler(handler); // Message with level lower will be discarded logger.setLevel(Level.ALL); // Log a message logger.log(Level.WARNING, "Some problem"); } catch (SecurityException e) {

AIX and SOLARIS maintenance commands

AIX and SOLARIS uname unix name, check which unix is used uname // OS name uname -r // OS version uname -a // OS name, host, version df info about disk space df -v // percent of used blocks df -vk // 1024-byte blocks df -vm // MB blocks df -gm // GB blocks AIX topas statistics about the activity on the local system // all statistics topas // -w WLM - WorkLoad Management topas -w SOLARIS prstat identify which processes are consuming the CPU // -s cpu flag sorts by CPU usage (default), -n 5 flag restricts top five processes prstat -s cpu -n 5 // -a summary of a consumption of resources by an user prstat -s cpu -a prstat -s cpu -a -n 5 ps process status ps -eo pid,pmem,vsz,rss,comm | sort -rnk2 | head