getconstructor

问题 I can't seem to use getConstructor for constructors with no parameters. I keep getting the following exception: java.lang.NoSuchMethodException: classname.<init>() Here is the code: interface InfoInterface { String getClassName(); String getMethodName(); String getArgument(); } class asa implements InfoInterface { @Override public String getClassName() { return ("jeden"); } @Override public String getMethodName() { return ("metoda"); } @Override public String getArgument() { return ("krzyk");

问题 This is a study project. I have three database classes A,B,C. There is a factory class that receives thru its constructor which class's object to create. Each of the three classes[A,B,C] has a constructor with a parameter to supply the database connection object. This is the code I'm using in the factory class's createObject method: Type classtyp = Type.GetType(className); Type[] constrParam = new Type[1]; constrParam[0] = typeof(DBConnection); ConstructorInfo constr = database.GetConstructor

问题 I have compiled a class at runtime which I would like to use on the fly, provided that its constructor takes one parameter package com.notmycompany; import com.mycompany.Manager; import com.mycompany.Processor; import com.mycompany.Event; public class CustomProcessor extends Processor { public CustomProcessor( Manager m) { super( m); } @Override public void process( Event evt) { // Do you own stuff System.out.println( "My Own Stuff"); } } Compilation goes fine and I can load the class right

问题 Lets say I have classes A and B , where B extends A . I also have a constructor in B with one argument which is of type A . I also have an object of type B called bObj . Is there a way to call B.class.getConstructor(new Class[] { bObj.getClass() }) and get the constructor since B extends A ? At the moment I'm getting a NoSuchMethodException . Regards, Stan 回答1: I suggest you have a look at the ConstructorUtils from Apache Commons Lang. They have all manners of constructor discovery methods.