看看JavaCompiler
下面基于 JavaDocs 中给出的示例
这将在目录中保存一个(基于名称要求)并将 编译为Java类...File
testcompile
package
File
package inlinecompiler;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.tools.Diagnostic;
import javax.tools.DiagnosticCollector;
import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.StandardJavaFileManager;
import javax.tools.ToolProvider;
public class InlineCompiler {
public static void main(String[] args) {
StringBuilder sb = new StringBuilder(64);
sb.append("package testcompile;\n");
sb.append("public class HelloWorld implements inlinecompiler.InlineCompiler.DoStuff {\n");
sb.append(" public void doStuff() {\n");
sb.append(" System.out.println(\"Hello world\");\n");
sb.append(" }\n");
sb.append("}\n");
File helloWorldJava = new File("testcompile/HelloWorld.java");
if (helloWorldJava.getParentFile().exists() || helloWorldJava.getParentFile().mkdirs()) {
try {
Writer writer = null;
try {
writer = new FileWriter(helloWorldJava);
writer.write(sb.toString());
writer.flush();
} finally {
try {
writer.close();
} catch (Exception e) {
}
}
/** Compilation Requirements *********************************************************************************************/
DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<JavaFileObject>();
JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
StandardJavaFileManager fileManager = compiler.getStandardFileManager(diagnostics, null, null);
// This sets up the class path that the compiler will use.
// I've added the .jar file that contains the DoStuff interface within in it...
List<String> optionList = new ArrayList<String>();
optionList.add("-classpath");
optionList.add(System.getProperty("java.class.path") + File.pathSeparator + "dist/InlineCompiler.jar");
Iterable<? extends JavaFileObject> compilationUnit
= fileManager.getJavaFileObjectsFromFiles(Arrays.asList(helloWorldJava));
JavaCompiler.CompilationTask task = compiler.getTask(
null,
fileManager,
diagnostics,
optionList,
null,
compilationUnit);
/********************************************************************************************* Compilation Requirements **/
if (task.call()) {
/** Load and execute *************************************************************************************************/
System.out.println("Yipe");
// Create a new custom class loader, pointing to the directory that contains the compiled
// classes, this should point to the top of the package structure!
URLClassLoader classLoader = new URLClassLoader(new URL[]{new File("./").toURI().toURL()});
// Load the class from the classloader by name....
Class<?> loadedClass = classLoader.loadClass("testcompile.HelloWorld");
// Create a new instance...
Object obj = loadedClass.newInstance();
// Santity check
if (obj instanceof DoStuff) {
// Cast to the DoStuff interface
DoStuff stuffToDo = (DoStuff)obj;
// Run it baby
stuffToDo.doStuff();
}
/************************************************************************************************* Load and execute **/
} else {
for (Diagnostic<? extends JavaFileObject> diagnostic : diagnostics.getDiagnostics()) {
System.out.format("Error on line %d in %s%n",
diagnostic.getLineNumber(),
diagnostic.getSource().toUri());
}
}
fileManager.close();
} catch (IOException | ClassNotFoundException | InstantiationException | IllegalAccessException exp) {
exp.printStackTrace();
}
}
}
public static interface DoStuff {
public void doStuff();
}
}
现在更新为包括为编译器提供类路径以及加载和执行已编译的类!