如何加载外部java类并使用参数调用方法

Question

我试图加载一个具有特定url的类，并通过向它们传递相同的值来调用该类中的方法

我不知道该怎么做

我的url看起来像这样：“文件：/C:/Users/Retro/Desktop/best-project-2/mutants/traditional\u mutants/Complex\u cconvolve（Complex，Complex）/AOIS\u 136/FFT.class”

我试着像这样加载类

package com.company.fileIterator;


import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.List;



public class CallMutant {
    public static void main(String[] args) throws IOException {
        FolderIterator folderTestRunner = new FolderIterator();
        List<String> list = folderTestRunner.getFilesPath();

        URL url;
        try{
            url = new URL("file:///"+list.get(5));
            System.out.println(url);
            URLClassLoader ucl = new URLClassLoader(new URL[]{url});
            Class clazz = ucl.loadClass("FFT");
            Object o = clazz.newInstance();
            System.out.println(o.toString());
        } catch (MalformedURLException e){
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        }


    }

}

主要目标是加载具有相同名称和方法的多个类

谢谢你的帮助

Answer 1

FTT。类，我也有相同的文件，只是扩展名为java

public class FFT {
    public FFT() {
    }

    public static Complex[] fft(Complex[] var0) {
        int var1 = var0.length;
        if (var1 == 1) {
            return new Complex[]{var0[0]};
        } else if (var1 % 2 != 0) {
            throw new RuntimeException("N is not a power of 2");
        } else {
            Complex[] var2 = new Complex[var1 / 2];

            for(int var3 = 0; var3 < var1 / 2; ++var3) {
                var2[var3] = var0[2 * var3];
            }

            Complex[] var11 = fft(var2);
            Complex[] var4 = var2;

            for(int var5 = 0; var5 < var1 / 2; ++var5) {
                var4[var5] = var0[2 * var5 + 1];
            }

            Complex[] var12 = fft(var4);
            Complex[] var6 = new Complex[var1];

            for(int var7 = 0; var7 < var1 / 2; ++var7) {
                double var8 = (double)(-2 * var7) * 3.141592653589793D / (double)var1;
                Complex var10 = new Complex(Math.cos(var8), Math.sin(var8));
                var6[var7] = var11[var7].plus(var10.times(var12[var7]));
                var6[var7 + var1 / 2] = var11[var7].minus(var10.times(var12[var7]));
            }

            return var6;
        }
    }

    public static Complex[] ifft(Complex[] var0) {
        int var1 = var0.length;
        Complex[] var2 = new Complex[var1];

        int var3;
        for(var3 = 0; var3 < var1; ++var3) {
            var2[var3] = var0[var3].conjugate();
        }

        var2 = fft(var2);

        for(var3 = 0; var3 < var1; ++var3) {
            var2[var3] = var2[var3].conjugate();
        }

        for(var3 = 0; var3 < var1; ++var3) {
            var2[var3] = var2[var3].times(1.0D / (double)var1);
        }

        return var2;
    }

    public static Complex[] cconvolve(Complex[] var0, Complex[] var1) {
        if (var0.length != var1.length) {
            throw new RuntimeException("Dimensions don't agree");
        } else {
            int var2 = var0.length;
            Complex[] var3 = fft(var0);
            Complex[] var4 = fft(var1);
            Complex[] var5 = new Complex[var2];

            for(int var6 = 0; var6 < var2; ++var6) {
                var5[var6] = var3[var6].times(var4[var6]);
            }

            return ifft(var5);
        }
    }

    public static Complex[] convolve(Complex[] var0, Complex[] var1) {
        Complex var2 = new Complex(0.0D, 0.0D);
        Complex[] var3 = new Complex[2 * var0.length];

        int var4;
        for(var4 = 0; var4 < var0.length; ++var4) {
            var3[var4 ] = var0[var4];
        }

        for(var4 = var0.length; var4 < 2 * var0.length; ++var4) {
            var3[var4] = var2;
        }

        Complex[] var6 = new Complex[2 * var1.length];

        int var5;
        for(var5 = 0; var5 < var1.length; ++var5) {
            var6[var5] = var1[var5];
        }

        for(var5 = var1.length; var5 < 2 * var1.length; ++var5) {
            var6[var5] = var2;
        }

        return cconvolve(var3, var6);
    }

    public static void main(String[] var0) {
        int var1 = Integer.parseInt(var0[0]);
        Complex[] var2 = new Complex[var1];

        int var3;
        for(var3 = 0; var3 < var1; ++var3) {
            var2[var3] = new Complex((double)var3, 0.0D);
            var2[var3] = new Complex(-2.0D * Math.random() + 1.0D, 0.0D);
        }

        System.out.println("x");
        System.out.println("         -");

        for(var3 = 0; var3 < var1; ++var3) {
            System.out.println(var2[var3]);
        }

        System.out.println();
        Complex[] var8 = fft(var2);
        System.out.println("y = fft(x)");
        System.out.println("         -");

        for(int var4 = 0; var4 < var1; ++var4) {
            System.out.println(var8[var4]);
        }

        System.out.println();
        Complex[] var9 = ifft(var8);
        System.out.println("z = ifft(y)");
        System.out.println("         -");

        for(int var5 = 0; var5 < var1; ++var5) {
            System.out.println(var9[var5]);
        }

        System.out.println();
        Complex[] var10 = cconvolve(var2, var2);
        System.out.println("c = cconvolve(x, x)");
        System.out.println("         -");

        for(int var6 = 0; var6 < var1; ++var6) {
            System.out.println(var10[var6]);
        }

        System.out.println();
        Complex[] var11 = convolve(var2, var2);
        System.out.println("d = convolve(x, x)");
        System.out.println("         -");

        for(int var7 = 0; var7 < var11.length; ++var7) {
            System.out.println(var11[var7]);
        }

        System.out.println();
    }
}

呼叫变种人。java//

完整链接

名单。get（5）=C:\Users\Retro\Desktop\best-project-2\mutants\traditional\u mutants\Complex\u cconvolve（Complex，Complex）\AOIS\u 136\FFT。班 包裹通讯。公司文件迭代器

import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.List;



public class CallMutant {
    public static void main(String[] args) throws IOException {
        FolderIterator folderTestRunner = new FolderIterator();
        List<String> list = folderTestRunner.getFilesPath();

        URL url;
        try{
            url = new URL("file:///"+list.get(5));
            URLClassLoader ucl = new URLClassLoader(new URL[]{url});
            Class clazz = ucl.loadClass("FFT");
            Object o = clazz.newInstance();
            System.out.println(o.toString());
        } catch (MalformedURLException e){
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        }


    }

}

Answer 2

好的，所以我最后做的是反射。我创建了一个临时文件，复制了原始FFT类的所有代码，将类名更改为与文件名相同，最后编译了新文件并调用了必要的方法

成功了

public class CallMutant {

    public static void main(String[] args) throws IOException {
        // get mutant list
        List<String> list = FolderIterator.getFilesPath();
        for (int i = 0; i < list.size(); i++) {
            System.out.println("Iter: "+ i);
            File source = new File(list.get(i));
            File dest = File.createTempFile("FFT", ".java");
            dest.deleteOnExit();
            System.out.format("Canonical filename: %s\n", dest.getCanonicalFile());

            //copy file using Stream
            try {
                copyFileUsingStream(source, dest);
            } catch (IOException e) {
                e.printStackTrace();
            }

            // generate the source code, using the source filename as the class name
            String classname = dest.getName().split("\\.")[0];
            Path path = Paths.get(String.valueOf(dest));
            Charset charset = StandardCharsets.UTF_8;

            String content = new String(Files.readAllBytes(path), charset);
            content = content.replaceAll("public class FFT", "public class " + classname);
            Files.write(path, content.getBytes(charset));

            // compile the source file
            JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
            StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null);
            File parentDirectory = dest.getParentFile();
            fileManager.setLocation(StandardLocation.CLASS_OUTPUT, Arrays.asList(parentDirectory));
            Iterable<? extends JavaFileObject> compilationUnits = fileManager.getJavaFileObjectsFromFiles(Arrays.asList(dest));
            compiler.getTask(null, fileManager, null, null, null, compilationUnits).call();
            fileManager.close();

            // load the compiled class
            URLClassLoader classLoader = URLClassLoader.newInstance(new URL[]{parentDirectory.toURI().toURL()});
            Class<?> helloClass = null;
            try {
                helloClass = classLoader.loadClass(classname);
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
                System.out.println("No class found");
            }

            // call a method on the loaded class
            Method helloMethod = null;
            try {
                Complex[] params2 = new Complex[1];
                helloMethod = helloClass.getDeclaredMethod("main", String[].class);
            } catch (NoSuchMethodException e) {
                System.out.println("No Method found");
                e.printStackTrace();
            }
            try {
                String[] params = {"1"};
                helloMethod.invoke(helloClass.newInstance(), (Object) params);
            }catch (IllegalAccessException | InvocationTargetException | InstantiationException e) {
                e.printStackTrace();
            }
        }
    }
    private static void copyFileUsingStream(File source, File dest) throws IOException {
        InputStream is = null;
        OutputStream os = null;
        try {
            is = new FileInputStream(source);
            os = new FileOutputStream(dest);
            byte[] buffer = new byte[1024];
            int length;
            os.write("import com.company.originals.Complex;\n".getBytes());
            while ((length = is.read(buffer)) > 0) {
                os.write(buffer, 0, length);
            }
        } finally {
            is.close();
            os.close();
        }
    }
}

Answer 3

我不明白你的意思。为什么不编译这个类文件的jar文件，并将其作为依赖项包含在项目中（比如see here）？在这种情况下使用类加载器和反射既慢又不安全