我正试图在AspectJ中实现非公共类的对象。
我有这堂课:
package ca1.business;
public class Bill {
int id;
String idOperator;
String idClient;
Bill(int id, String idOperator, String idClient) { /* (...) */ }
public String toString() { /* (...) */ }
public boolean equals(Object o) { /* (...) */ }
public int getId() { /* (...) */ }
public String getOperator() { /* (...) */ }
public String getClient() { /* (...) */ }
}
在我希望能够做到的方面课程中:
Bill b = new Bill(currInvoice, idOperator, idClient);
问题是我收到错误:
The constructor Bill(int, String, String) is not visible
所以我调查并尝试使用像this帖子中解释的那样的反射。
try {
Constructor<Bill> cons = Bill.class.getDeclaredConstructor(null);
cons.setAccessible(true);
Bill invoice = cons.newInstance(null);
invoice.id = 1;
invoice.idOperator = "foo";
invoice.idClient = "bar";
// etc...
} catch (SecurityException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
但我在行中出错:
invoice.id = 1;
invoice.idOperator = "foo";
invoice.idClient = "bar";
错误是:
The field Bill.X is not visible.
有没有人知道是否有任何解决方法?
答案 0 :(得分:1)
为什么要使用反射?
让我们假设Bill
类看起来像这样:
package ca1.business;
public class Bill {
int id;
String idOperator;
String idClient;
Bill(int id, String idOperator, String idClient) {
this.id = id;
this.idOperator = idOperator;
this.idClient = idClient;
}
@Override
public String toString() {
return "Bill [id=" + id + ", idOperator=" + idOperator + ", idClient=" + idClient + "]";
}
public static Bill instance;
public static void main(String[] args) {
System.out.println(instance);
}
}
我们希望我们的方面在执行main
之前填充静态成员(愚蠢的例子,仅用于演示):
选项A:特权方面
package de.scrum_master.aspect;
import ca1.business.Bill;
public privileged aspect MyAspect {
before() : execution(public static void main(String[])) {
Bill.instance = new Bill(11, "operator", "client");
}
}
选项B:将方面放入包ca1.business
构造函数是package-private,即同一个包中的其他类可以访问它。
package ca1.business;
public aspect MyAspect {
before() : execution(public static void main(String[])) {
Bill.instance = new Bill(11, "operator", "client");
}
}
选项C:将工厂类作为帮助程序放入受保护的包中
package ca1.business;
public class BillFactory {
public static Bill create(int id, String idOperator, String idClient) {
return new Bill(id, idOperator, idClient);
}
}
package de.scrum_master.aspect;
import ca1.business.Bill;
import ca1.business.BillFactory;;
public aspect MyAspect {
before() : execution(public static void main(String[])) {
Bill.instance = BillFactory.create(11, "operator", "client");
}
}
每个选项A,B,C的控制台日志
Bill [id=11, idOperator=operator, idClient=client]