开发一个工具类,该工具类提供一个eval方法,实现javascript函数的eval功能

package load;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.lang.reflect.Method;

public class EvalTest {

    /**
     * @param args
     * @throws Exception
     */
    //
    public static void eval(String str) throws Exception{
        File file = new File("D:\\201105\\java\\src\\load\\Eval.java");
        if(!file.exists()){
            file.createNewFile();
        }
        FileOutputStream fos = new FileOutputStream(file);
        OutputStreamWriter ow = new OutputStreamWriter(fos);
        PrintWriter pw = new PrintWriter(ow);
        BufferedWriter bw = new BufferedWriter(ow);
        StringBuilder sb = new StringBuilder();
        sb.append("public class Eval{");
        sb.append("public void eval(){");
        sb.append(str);
        sb.append("}");
        sb.append("}");
        pw.write(sb.toString());
        pw.close();
    }
   
   
   
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        try {
            eval("System.out.println(\"eval 测试成功了,可以去asfd吃饭了\");");
            Class eval = Class.forName("load.Eval");
            Method me = eval.getDeclaredMethod("eval", null);
            me.invoke(eval.newInstance(), null);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}