With the help of compiler API we can run or compile a java source code. I am giving you an example to compile a source code stored in a String and to compile and run a .java file. Let´s consider an example in which we have Test.java file to be compiled and run.
Test.java:
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public class Test {
public static void main(String s1[]){
System.out.print("Hello Test");
}
}
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Following is the java file which compile and run the above .java file and compile the source code stored in a String.
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CompileString.java:
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import java.lang.reflect.Method;
import java.net.URI;
import java.util.Iterator;
import java.util.NoSuchElementException;
import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.SimpleJavaFileObject;
import javax.tools.ToolProvider;
public class CompileString {
public static void main(String[] args) throws Exception {
JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
String program = "class Test123{" + " public static void main (String [] args1){"
+ " System.out.println (\"Hello, World\");"
+ " System.out.println (args1.length);" + " }" + "}";
Iterable<? extends JavaFileObject> fileObjects;
fileObjects = getJavaSourceFromString(program);
compiler.getTask(null, null, null, null, null, fileObjects).call();
Class<?> clazz = Class.forName("Test");
Method m = clazz.getMethod("main", new Class[] { String[].class });
Object[] _args = new Object[] { new String[0] };
m.invoke(null, _args);
}
static Iterable<JavaSourceFromString> getJavaSourceFromString(String code) {
final JavaSourceFromString jsfs;
jsfs = new JavaSourceFromString("code", code);
return new Iterable<JavaSourceFromString>() {
public Iterator<JavaSourceFromString> iterator() {
return new Iterator<JavaSourceFromString>() {
boolean isNext = true;
public boolean hasNext() {
return isNext;
}
public JavaSourceFromString next() {
if (!isNext)
throw new NoSuchElementException();
isNext = false;
return jsfs;
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
};
}
}
class JavaSourceFromString extends SimpleJavaFileObject {
final String code;
JavaSourceFromString(String name, String code) {
super(URI.create("string:///" + name.replace(´.´, ´/´) + Kind.SOURCE.extension), Kind.SOURCE);
this.code = code;
}
public CharSequence getCharContent(boolean ignoreEncodingErrors) {
return code;
}
}
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Following is the example with Eclipse or MyEclipse IDE:
To download the example
Click Here
