jdk 5.0) In runtime, java compile.

인터냇에서 찾은 미국사람의 싸이트에서 수정을 하고, 올린 글임..

제대로 컴파일되게 했다..

 

시간을 이용하여, 파일을 만들고. 그 파일을 실시간으로 컴파일하는 샘플 예제이다.

 

import java.io.*;
import java.util.*;
import java.lang.reflect.*;
import com.sun.tools.javac.Main;

 

/**

 * author @knight

 */

public class MakeTodayClass {
  Date today = new Date();
  String todayMillis = Long.toString(today.getTime());
  String todayClass = "z_" + todayMillis;
  String todaySource = todayClass + ".java";

  public static void main (String args[]){
    MakeTodayClass mtc = new MakeTodayClass();
    mtc.createIt();
    if (mtc.compileIt()) {
       System.out.println("Running " + mtc.todayClass + ":\n\n");
       mtc.runIt();
       }
    else
       System.out.println(mtc.todaySource + " is bad.");
    }

  public void createIt() {
    try {
      FileWriter aWriter = new FileWriter(todaySource, true);
      aWriter.write("public class "+ todayClass + "{");
      aWriter.write(" public void print() {");
      aWriter.write(" System.out.println(\""+todayMillis+"\");");
      aWriter.write(" }}\n");
      aWriter.flush();
      aWriter.close();
      }
    catch(Exception e){
      e.printStackTrace();
      }
    }

  public boolean compileIt() {
      try {
        String [] source = { new String(todaySource)};
        com.sun.tools.javac.Main main = new com.sun.tools.javac.Main();
        main.compile(source);
      }  catch (Exception e) {
          e.printStackTrace();
          return false;
      }
    return true;
    }

  public void runIt() {
    try {
      Class params[] = {};
      Object paramsObj[] = {};
      Class thisClass = Class.forName(todayClass);
      Object iClass = thisClass.newInstance();
      Method thisMethod = thisClass.getDeclaredMethod("print", params);
      thisMethod.invoke(iClass, paramsObj);
      }
    catch (Exception e) {
      e.printStackTrace();
      }
    }
 }