假设您有以下构造函数

class MyClass {
    public MyClass(Long l, String s, int i) {

    }
}

你需要像这样表明你打算使用这个构造函数:

Class classToLoad = MyClass.class;

Class[] cArg = new Class[3]; //Our constructor has 3 arguments
cArg[0] = Long.class; //First argument is of *object* type Long
cArg[1] = String.class; //Second argument is of *object* type String
cArg[2] = int.class; //Third argument is of *primitive* type int

Long l = new Long(88);
String s = "text";
int i = 5;

classToLoad.getDeclaredConstructor(cArg).newInstance(l, s, i);

不要使用Class.newInstance();为什么Class.newInstance()是邪恶的?

像其他答案说，使用Constructor.newInstance()代替。

你可以使用Class的getDeclaredConstructor方法。它需要一个类数组。下面是一个经过测试的工作示例:

public static JFrame createJFrame(Class c, String name, Component parentComponent)
{
    try
    {
        JFrame frame = (JFrame)c.getDeclaredConstructor(new Class[] {String.class}).newInstance("name");
        if (parentComponent != null)
        {
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        }
        else
        {
            frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        }
        frame.setLocationRelativeTo(parentComponent);
        frame.pack();
        frame.setVisible(true);
    }
    catch (InstantiationException instantiationException)
    {
        ExceptionHandler.handleException(instantiationException, parentComponent, Language.messages.get(Language.InstantiationExceptionKey), c.getName());
    }
    catch(NoSuchMethodException noSuchMethodException)
    {
        //ExceptionHandler.handleException(noSuchMethodException, parentComponent, Language.NoSuchMethodExceptionKey, "NamedConstructor");
        ExceptionHandler.handleException(noSuchMethodException, parentComponent, Language.messages.get(Language.NoSuchMethodExceptionKey), "(Constructor or a JFrame method)");
    }
    catch (IllegalAccessException illegalAccessException)
    {
        ExceptionHandler.handleException(illegalAccessException, parentComponent, Language.messages.get(Language.IllegalAccessExceptionKey));
    }
    catch (InvocationTargetException invocationTargetException)
    {
        ExceptionHandler.handleException(invocationTargetException, parentComponent, Language.messages.get(Language.InvocationTargetExceptionKey));
    }
    finally
    {
        return null;
    }
}

假设您有以下构造函数

class MyClass {
    public MyClass(Long l, String s, int i) {

    }
}

你需要像这样表明你打算使用这个构造函数:

Class classToLoad = MyClass.class;

Class[] cArg = new Class[3]; //Our constructor has 3 arguments
cArg[0] = Long.class; //First argument is of *object* type Long
cArg[1] = String.class; //Second argument is of *object* type String
cArg[2] = int.class; //Third argument is of *primitive* type int

Long l = new Long(88);
String s = "text";
int i = 5;

classToLoad.getDeclaredConstructor(cArg).newInstance(l, s, i);

这就是我如何使用动态构造函数args list创建Class clazz的实例。

final Constructor constructor = clazz.getConstructors()[0];
final int constructorArgsCount = constructor.getParameterCount();
if (constructorArgsCount > 0) {
    final Object[] constructorArgs = new Object[constructorArgsCount];
    int i = 0;
    for (Class parameterClass : constructor.getParameterTypes()) {
        Object dummyParameterValue = getDummyValue(Class.forName(parameterClass.getTypeName()), null);
        constructorArgs[i++] = dummyParameterValue;
    }
    instance = constructor.newInstance(constructorArgs);
} else {
    instance = clazz.newInstance();
}

这就是getDummyValue()方法的样子，

private static Object getDummyValue(final Class clazz, final Field field) throws Exception {
    if (int.class.equals(clazz) || Integer.class.equals(clazz)) {
        return DUMMY_INT;
    } else if (String.class.equals(clazz)) {
        return DUMMY_STRING;
    } else if (boolean.class.equals(clazz) || Boolean.class.equals(clazz)) {
        return DUMMY_BOOL;
    } else if (List.class.equals(clazz)) {
        Class fieldClassGeneric = Class.forName(((ParameterizedType) field.getGenericType()).getActualTypeArguments()[0].getTypeName());
        return List.of(getDummyValue(fieldClassGeneric, null));
    } else if (USER_DEFINED_CLASSES.contains(clazz.getSimpleName())) {
        return createClassInstance(clazz);
    } else {
         throw new Exception("Dummy value for class type not defined - " + clazz.getName();
    }
}

MyClass.class.getDeclaredConstructor(String.class).newInstance("HERESMYARG");

or

obj.getClass().getDeclaredConstructor(String.class).newInstance("HERESMYARG");