Java --专注EBS

System.getProperties().put("http.proxyHost",   "someProxyURL");  
System.getProperties().put("http.proxyPort",   "someProxyPort");  
System.getProperties().put("http.proxyUser",   "someUserName");  
System.getProperties().put("http.proxyPassword",   "somePassword"); 

System.getProperties().put("http.proxyHost",   "someProxyURL");
System.getProperties().put("http.proxyPort",   "someProxyPort");
System.getProperties().put("http.proxyUser",   "someUserName");
System.getProperties().put("http.proxyPassword",   "somePassword");

Read this article for more   details.
Update: Thanks Markus for the comment. I have updated the code and   changed it to
more robust implementation.


public class SimpleSingleton {  
private static SimpleSingleton singleInstance =  new SimpleSingleton  ();  

//Marking default constructor   private  
//to avoid direct   instantiation.  
private SimpleSingleton()   {  
}  

//Get instance for class SimpleSingleton  
public static SimpleSingleton getInstance() {  

return   singleInstance;  
}  
} 

public class SimpleSingleton {
private static SimpleSingleton   singleInstance =  new SimpleSingleton();
//Marking default constructor private
//to avoid direct   instantiation.
private SimpleSingleton() {
}
//Get instance for class SimpleSingleton
public static   SimpleSingleton getInstance() {
return singleInstance;
}
}
One more implementation of   Singleton class. Thanks to Ralph and Lukasz Zielinski
for pointing this out.


public enum SimpleSingleton {  
INSTANCE;  
public void doSomething()   {  
}  
}  

//Call the method from Singleton:  
SimpleSingleton.INSTANCE.doSomething(); 

public enum SimpleSingleton {
INSTANCE;
public void   doSomething() {
}
}
//Call the method from Singleton:
SimpleSingleton.INSTANCE.doSomething();

Read this article for more details.

import   java.awt.Dimension;  
import java.awt.Rectangle;  
import java.awt.Robot;  
import java.awt.Toolkit;  
import java.awt.image.BufferedImage;  
import   javax.imageio.ImageIO;  
import java.io.File;  

...  

public void captureScreen(String fileName)   throws Exception {  

Dimension screenSize =   Toolkit.getDefaultToolkit().getScreenSize();  
Rectangle   screenRectangle = new Rectangle(screenSize);  
Robot   robot = new Robot();  
BufferedImage image =   robot.createScreenCapture(screenRectangle);  
ImageIO.write(image, "png", new File(fileName));  

}    
... 

import java.awt.Dimension;
import java.awt.Rectangle;
import   java.awt.Robot;
import java.awt.Toolkit;
import   java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import   java.io.File;
...
public void captureScreen(String fileName) throws Exception {
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize  ();
Rectangle screenRectangle = new Rectangle  (screenSize);
Robot robot = new Robot();
BufferedImage image = robot.createScreenCapture(screenRectangle);
ImageIO.write(image, "png", new File(fileName));
}
...

>File dir = new File("directoryName");  
String[] children = dir.list();  
if (children ==   null) {  
// Either dir does not exist   or is not a directory  
} else {  
for (int i=0; i < children.length; i++)   {  
// Get   filename of file or directory  
String filename =   children[i];  
}  
}  

// It is also possible to filter the   list of returned files.  
// This example does not return any   files that start with `.'.  
FilenameFilter filter = new   FilenameFilter() {  
public boolean   accept(File dir, String name) {  
return !name.startsWith  (".");  
}  
};  
children = dir.list(filter);  

// The list of files can also be retrieved as File objects  
File[] files = dir.listFiles();  

//   This filter only returns directories  
FileFilter fileFilter =   new FileFilter() {  
public boolean   accept(File file) {  
return file.isDirectory  ();  
}  
};  
files = dir.listFiles(fileFilter); 

File dir = new File("directoryName");
String[]   children = dir.list();
if (children == null)   {
// Either dir does not exist or is   not a directory
} else   {
for (int i=0; i <   children.length; i++)   {
// Get   filename of file or   directory
String filename = children[i];
}
}
// It is also possible to filter the list of returned   files.
// This example does not return any files that start   with `.'.
FilenameFilter filter = new FilenameFilter()   {
public boolean accept(File dir,   String name)   {
return !  name.startsWith(".");
}
};
children = dir.list(filter);
// The list of files can also be retrieved as File   objects
File[] files = dir.listFiles();
// This filter only returns directories
FileFilter fileFilter = new FileFilter()   {
public boolean accept(File file)   {
return   file.isDirectory();
}
};
files = dir.listFiles  (fileFilter);

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<?xml version="1.0"?> 
<students> 
<student> 
<name>John</name> 
<grade>B</grade> 
<age>12</age> 
</student> 
<student> 
<name>Mary</name> 
<grade>A</grade> 
<age>11</age> 
</student> 
<student> 
<name>Simon</name> 
<grade>A</grade> 
<age>18</age> 
</student> 
</students> 

<?xml version="1.0"?>
<students>
<student>
<name>John</name>
<grade>B</grade>
<age>12</age>
</student>
<student>
<name>Mary</name>
<grade>A</grade>
<age>11</age>
</student>
<student>
<name>Simon</name>
<grade>A</grade>
<age>18</age>
</student>
</students>
Java code to parse above XML.
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package net.viralpatel.java.xmlparser;  

import java.io.File;  
import javax.xml.parsers.DocumentBuilder;  
import javax.xml.parsers.DocumentBuilderFactory;  

import org.w3c.dom.Document;  
import org.w3c.dom.Element;  
import org.w3c.dom.Node;  
import org.w3c.dom.NodeList;  

public class XMLParser {  

public void getAllUserNames(String fileName) {  
try {  
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();  
DocumentBuilder db = dbf.newDocumentBuilder();  
File file = new File(fileName);  
if (file.exists()) {  
Document doc = db.parse(file);  
Element docEle = doc.getDocumentElement();  

// Print root element of the document  
System.out.println("Root element of the document: " 
+ docEle.getNodeName());  

NodeList studentList = docEle.getElementsByTagName("student");  

// Print total student elements in document  
System.out  
.println("Total students: " + studentList.getLength());  

if (studentList != null && studentList.getLength() > 0) {  
for (int i = 0; i < studentList.getLength(); i++) {  

Node node = studentList.item(i);  

if (node.getNodeType() == Node.ELEMENT_NODE) {  

System.out  
.println("=====================");  

Element e = (Element) node;  
NodeList nodeList = e.getElementsByTagName("name");  
System.out.println("Name: " 
+ nodeList.item(0).getChildNodes().item(0)  
.getNodeValue());  

nodeList = e.getElementsByTagName("grade");  
System.out.println("Grade: " 
+ nodeList.item(0).getChildNodes().item(0)  
.getNodeValue());  

nodeList = e.getElementsByTagName("age");  
System.out.println("Age: " 
+ nodeList.item(0).getChildNodes().item(0)  
.getNodeValue());  
}  
}  
} else {  
System.exit(1);  
}  
}  
} catch (Exception e) {  
System.out.println(e);  
}  
}  
public static void main(String[] args) {  

XMLParser parser = new XMLParser();  
parser.getAllUserNames("c:\\test.xml");  
}  
} 

package net.viralpatel.java.xmlparser;
import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class XMLParser {
public void getAllUserNames(String fileName) {
try {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
File file = new File(fileName);
if (file.exists()) {
Document doc = db.parse(file);
Element docEle = doc.getDocumentElement();
// Print root element of the document
System.out.println("Root element of the document: "
+ docEle.getNodeName());
NodeList studentList = docEle.getElementsByTagName("student");
// Print total student elements in document
System.out
.println("Total students: " + studentList.getLength());
if (studentList != null && studentList.getLength() > 0) {
for (int i = 0; i < studentList.getLength(); i++) {
Node node = studentList.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
System.out
.println("=====================");
Element e = (Element) node;
NodeList nodeList = e.getElementsByTagName("name");
System.out.println("Name: "
+ nodeList.item(0).getChildNodes().item(0)
.getNodeValue());
nodeList = e.getElementsByTagName("grade");
System.out.println("Grade: "
+ nodeList.item(0).getChildNodes().item(0)
.getNodeValue());
nodeList = e.getElementsByTagName("age");
System.out.println("Age: "
+ nodeList.item(0).getChildNodes().item(0)
.getNodeValue());
}
}
} else {
System.exit(1);
}
}
} catch (Exception e) {
System.out.println(e);
}
}
public static void main(String[] args) {
XMLParser parser = new XMLParser();
parser.getAllUserNames("c:\\test.xml");
}
}

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import java.util.Map;  
import org.apache.commons.lang.ArrayUtils;  

public class Main {  

public static void main(String[] args) {  
String[][] countries = { { "United States", "New York" }, { "United Kingdom", "London" },  
{ "Netherland", "Amsterdam" }, { "Japan", "Tokyo" }, { "France", "Paris" } };  

Map countryCapitals = ArrayUtils.toMap(countries);  

System.out.println("Capital of Japan is " + countryCapitals.get("Japan"));  
System.out.println("Capital of France is " + countryCapitals.get("France"));  
}  
} 

import java.util.Map;
import org.apache.commons.lang.ArrayUtils;
public class Main {
public static void main(String[] args) {
String[][] countries = { { "United States", "New York" }, { "United Kingdom", "London" },
{ "Netherland", "Amsterdam" }, { "Japan", "Tokyo" }, { "France", "Paris" } };
Map countryCapitals = ArrayUtils.toMap(countries);
System.out.println("Capital of Japan is " + countryCapitals.get("Japan"));
System.out.println("Capital of France is " + countryCapitals.get("France"));
}
}

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import javax.mail.*;  
import javax.mail.internet.*;  
import java.util.*;  

public void postMail( String recipients[ ], String subject, String message , String from) throws MessagingException  
{  
boolean debug = false;  

//Set the host smtp address  
Properties props = new Properties();  
props.put("mail.smtp.host", "smtp.example.com");  

// create some properties and get the default Session  
Session session = Session.getDefaultInstance(props, null);  
session.setDebug(debug);  

// create a message  
Message msg = new MimeMessage(session);  

// set the from and to address  
InternetAddress addressFrom = new InternetAddress(from);  
msg.setFrom(addressFrom);  

InternetAddress[] addressTo = new InternetAddress[recipients.length];  
for (int i = 0; i < recipients.length; i++)  
{  
addressTo[i] = new InternetAddress(recipients[i]);  
}  
msg.setRecipients(Message.RecipientType.TO, addressTo);  

// Optional : You can also set your custom headers in the Email if you Want  
msg.addHeader("MyHeaderName", "myHeaderValue");  

// Setting the Subject and Content Type  
msg.setSubject(subject);  
msg.setContent(message, "text/plain");  
Transport.send(msg);  
} 

import javax.mail.*;
import javax.mail.internet.*;
import java.util.*;
public void postMail( String recipients[ ], String subject, String message , String from) throws MessagingException
{
boolean debug = false;
//Set the host smtp address
Properties props = new Properties();
props.put("mail.smtp.host", "smtp.example.com");
// create some properties and get the default Session
Session session = Session.getDefaultInstance(props, null);
session.setDebug(debug);
// create a message
Message msg = new MimeMessage(session);
// set the from and to address
InternetAddress addressFrom = new InternetAddress(from);
msg.setFrom(addressFrom);
InternetAddress[] addressTo = new InternetAddress[recipients.length];
for (int i = 0; i < recipients.length; i++)
{
addressTo[i] = new InternetAddress(recipients[i]);
}
msg.setRecipients(Message.RecipientType.TO, addressTo);
// Optional : You can also set your custom headers in the Email if you Want
msg.addHeader("MyHeaderName", "myHeaderValue");
// Setting the Subject and Content Type
msg.setSubject(subject);
msg.setContent(message, "text/plain");
Transport.send(msg);
}

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import java.io.BufferedReader;  
import java.io.InputStreamReader;  
import java.net.URL;  

public class Main {  
public static void main(String[] args)  {  
try {  
URL my_url = new URL("http://www.viralpatel.net/blogs/");  
BufferedReader br = new BufferedReader(new InputStreamReader(my_url.openStream()));  
String strTemp = "";  
while(null != (strTemp = br.readLine())){  
System.out.println(strTemp);  
}  
} catch (Exception ex) {  
ex.printStackTrace();  
}  
}  
} 

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
public class Main {
public static void main(String[] args)  {
try {
URL my_url = new URL("http://www.viralpatel.net/blogs/");
BufferedReader br = new BufferedReader(new InputStreamReader(my_url.openStream()));
String strTemp = "";
while(null != (strTemp = br.readLine())){
System.out.println(strTemp);
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
}

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/** 
* Reallocates an array with a new size, and copies the contents 
* of the old array to the new array. 
* @param oldArray  the old array, to be reallocated. 
* @param newSize   the new array size. 
* @return          A new array with the same contents. 
*/ 
private static Object resizeArray (Object oldArray, int newSize) {  
int ldSize = java.lang.reflect.Array.getLength(oldArray);  
Class elementType = oldArray.getClass().getComponentType();  
Object newArray = java.lang.reflect.Array.newInstance(  
elementType,newSize);  
int preserveLength = Math.min(oldSize,newSize);  
if (preserveLength > 0)  
System.arraycopy (oldArray,0,newArray,0,preserveLength);  
return newArray;  
}  

// Test routine for resizeArray().  
public static void main (String[] args) {  
int[] a = {1,2,3};  
a = (int[])resizeArray(a,5);  
a[3] = 4;  
a[4] = 5;  
for (int i=0; i<a.length; i++)  
System.out.println (a[i]);  
}