Archive for the ‘How to’s’ Category
Read a File as String with Java
Thursday, June 16th, 2011
Introduction
I’m always Googling for a way to do this. This seems to be the best “idiomatic” solution I’ve found. So without further ado…
Example
public String readFile(String path) throws IOException {
FileInputStream stream = new FileInputStream(new File(path));
try{
FileChannel fc = stream.getChannel();
MappedByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
return Charset.defaultCharset().decode(bb).toString();
}
finally {
stream.close();
}
}
Tags: java
Posted in Development, How to's, quick tips | No Comments »
Unit Test Private Java Methods using Reflection
Thursday, May 5th, 2011
Introduction
I realise that the thought of Unit Testing private methods in Java classes can be like a red rag to a bull for some people and I understand the arguments.
Therefore, I present the following as a “how to”, not a moral argument for or against!
Example
The class under test
public class Product() {
private String privateMethod(String id) {
//Do something private
return "product_" + id;
}
}
The (Reflection Based) Unit Test
import java.lang.reflect.Method;
import static org.junit.Assert.*;
import org.junit.Test;
public class ProductTest {
private Product product; // the class under test
private Method m;
private static String METHOD_NAME = "privateMethod";
private Class[] parameterTypes;
private Object[] parameters;
@Before
public void setUp() throws Exception {
product = new Product();
parameterTypes = new Class[1];
parameterTypes[0] = java.lang.String.class;
m = product.getClass().getDeclaredMethod(METHOD_NAME, parameterTypes);
m.setAccessible(true);
parameters = new Object[1];
}
@Test
public void testPrivateMethod() throws Exception {
parameters[0] = "someIdentifier";
String result = (String) m.invoke(product, parameters);
//Do your assertions
assertNotNull(result);
}
}
Update
I’ve since been told that if dp4j.jar is in the classpath at compile-time, it will inject the necessary reflection to make this work. I haven’t had time to try this yet so YMMV.
Tags: java, junit, testing
Posted in Development, How to's | No Comments »
How to stop XSLT from escaping XML in output
Tuesday, September 28th, 2010
I was asked by a colleague today how to prevent XSLT from escaping XML “special characters” in its output. i.e. < was being escaped to < ;.
I didn't know but somebody else did...
<xsl:value-of select=”somethingWhichContainsXml” /> should be <xsl:value-of select=”somethingWhichContainsXml” disable-output-escaping=”yes” />
Tags: xml, xslt
Posted in Development, How to's | No Comments »
Display Version in Android Application
Thursday, August 26th, 2010
I was looking for a way to display the Version on the splash screen of my Android app, more specifically, the “versionName” as defined in the application’s AndroidManifest.xml
After A LOT of looking I discovered PackageInfo, which is a Java API to all of the info held in the manifest.
Armed with this information is was easy to produce the following:
private void displayVersionName() {
String versionName = "";
PackageInfo packageInfo;
try {
packageInfo = getPackageManager().getPackageInfo(getPackageName(), 0);
versionName = "v " + packageInfo.versionName;
} catch (NameNotFoundException e) {
e.printStackTrace();
}
TextView tv = (TextView) findViewById(R.id.versionNameTextView);
tv.setText(versionName);
}
Tags: android, java
Posted in Development, How to's | No Comments »
Log4j Nested Diagnostic Contexts (NDC)
Wednesday, June 2nd, 2010
Introduction and Problem
Log4j is a brilliant set of libraries which provides good “out of the box” logging capabilities.
Sometimes however, in multi-threaded environments (for example web apps), it can be hard to decipher the interleaved messages from the various clients
(more...)
Tags: java, log4j, logging
Posted in Development, How to's | No Comments »