Question

怎么使用jacob，以及常见问题总结

Answer 1

jacob 是java用来与用其它语言写的dll通信的桥.

1. 使用时我们必须先把jacob.dll 加载到系统system32 目录下 ,有些系统可以还需要用resvr32 ??.dll 注册。
还有就是要把jacob.jar 放到 classpath下，或者 当前项目的lib 库下。注意其的跟项目有关的.dll 文件也一般放在system32 目 录下面。

2. First load the library:
//Loading the library:
ActiveXComponent comp=new ActiveXComponent("Com.Calculation");
System.out.println("The Library been loaded, and an activeX component been created");
这可能会出现一个异常：ComFailException: Can't get object clsid from progid 这是因为你没有注册.dll 文件或者没有正确注册；

3.
int summation=Dispatch.call(comp, "sum",arg1,arg2).toInt();
System.out.println("Summation= "+ summation); int subtraction= Dispatch.call(comp,"subtract",arg1,arg2).toInt();
System.out.println("Subtraction= "+ subtraction);

int multiplication=Dispatch.call(comp,"multi",arg1,arg2).toInt();
System.out.println("Multiplication= "+ multiplication);

double division=Dispatch.call(comp,"div",arg1,arg2).toDouble();
System.out.println("Division= "+ division);

使用dispatch class ,第一个参数是dispatch组件 第二个是 函数名 ，第三，四个是参数

4. 如果想得到一个属性的值：
Dispatch. get(object, “Property Name”);

package jacobtest;

import com.jacob.activeX.*;
import com.jacob.com.*;
/**
* This class uses the the Jacob tech
* to use and interact with a Com cmponent
* in a java application
*/
public class ReadDLL {

public static void main(String[] args){

//Loading the library:
ActiveXComponent comp=new ActiveXComponent("Com.Calculation");
System.out.println("The Library been loaded, and an activeX component been created");

int arg1=100;
int arg2=50;
//using the functions from the library:
int summation=Dispatch.call(comp, "sum",arg1,arg2).toInt();
System.out.println("Summation= "+ summation);

int subtraction= Dispatch.call(comp,"subtract",arg1,arg2).toInt();
System.out.println("Subtraction= "+ subtraction);

int multiplication=Dispatch.call(comp,"multi",arg1,arg2).toInt();
System.out.println("Multiplication= "+ multiplication);

double division=Dispatch.call(comp,"div",arg1,arg2).toDouble();
System.out.println("Division= "+ division);

/**The following code is abstract of using the get,
* when the library contains a function that return
* some kind of a struct, and then get its properties and values
**/
// Dispatch disp=Dispatch.call(comp,"sum",100,10).toDispatch();
// DataType Var=Dispatch.get(disp,"Property Name");
}
}

输出结果：
Summation= 150
Subtraction= 50
Multiplication= 5000
Division= 2.0