java动态编译运行代码

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URI;
import java.util.Arrays;
import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.SimpleJavaFileObject;
import javax.tools.StandardJavaFileManager;
import javax.tools.ToolProvider;
import javax.tools.JavaCompiler.CompilationTask;
public class CompilerTest {
 public static void main(String[] args) throws Exception {
        String CLASSNAME = "TestClass";
  String source = "public class " + CLASSNAME +" { public static void main(String[] args) {System.out.println(/"Hello World!/");} }";
  JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
  StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null);
  JavaSourceFromString sourceObject = new JavaSourceFromString(CLASSNAME,source);
  Iterable<? extends JavaFileObject> fileObjects = Arrays.asList(sourceObject);
  CompilationTask task = compiler.getTask(null, fileManager, null, null,null, fileObjects);
  boolean result = task.call();
  if (result) {
   System.out.println("编译成功。");
   Runtime r = Runtime.getRuntime();
   Process p = r.exec("java " + CLASSNAME);
   BufferedReader br = new BufferedReader(new InputStreamReader(p
     .getInputStream()));
   StringBuffer sb = new StringBuffer();
   String inline;
   while (null != (inline = br.readLine())) {
    sb.append(inline).append("/n");
   }
   System.out.println(sb.toString());
  }
 }
}
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;
 }
}