【實例】java調用dll的文檔搜了不少，發現都不完整，或者說的不夠詳細，這里通過自己的實際操作，并將過程做了整理，通過實例說明java如何用jacob調用dll里的函數。
由于某系統加密需要，需要實現從dll里實現某些功能（比如獲取當前CPU序列號），并在Java中調用該函數。
（一）準備工作：需要用到文件有：jacob.dll和jacob.jar分別放到jdk/bin下和class_path下。文件下載地址：
（二）建立一個VB的Activex Dll 工程，命名為名為getCPU，自動生成Class1文件（工程名字和類名建議用英文名，以防調用時編碼出問題），并添加代碼如下：
Private Type OSVERSIONINFO
dwOSVersionInfoSize As Long
dwMajorVersion As Long
dwMinorVersion As Long
dwBuildNumber As Long
dwPlatformId As Long
szCSDVersion As String * 128 ' Maintenance string for PSS usage
End Type
Private Declare Function GetVersionEx Lib "kernel32" Alias "GetVersionExA" (lpVersionInformation As OSVERSIONINFO) As Long
Private Declare Function GetComputerName Lib "kernel32" Alias "GetComputerNameA" (ByVal lpBuffer As String, nSize As Long) As Long
Public Function GetCPUid(para As String) As String
On Error GoTo doError
Dim len5 As Long, aa As Long
Dim cmprName As String
Dim Computer As String
Dim CPUs As Object, MyCpu As Object
Dim osver As OSVERSIONINFO
Dim SerialNo As String
'取得Computer Name
cmprName = String(255, 0)
len5 = 256
aa = GetComputerName(cmprName, len5)
cmprName = Left(cmprName, InStr(1, cmprName, Chr(0)) - 1)
Computer = cmprName '取得CPU端口號
Set CPUs = GetObject("winmgmts:{impersonationLevel=impersonate}!\\" & Computer & "\root\cimv2").ExecQuery("select * from Win32_Processor")
For Each MyCpu In CPUs
SerialNo = MyCpu.ProcessorId
Exit For
Next
GetCPUid = SerialNo
Exit Function
doError:
GetCPUid = ""
End Function
保存后編譯為getCPU.dll 并復制到Windows/System32下。
（三）將dll導入為com組件
運行命令：regsvr32 C:\windows\system32\getCPU.dll 顯示成功導入。
（四）建立測試Java文件，內容如下：
package test;
import com.jacob.activeX.ActiveXComponent;
import com.jacob.com.*;
public class CallDll 
{
public static void main(String args[]) {
ActiveXComponent app = new ActiveXComponent("getCPU.Class1");
Dispatch mycom = (Dispatch) app.getObject();
if(mycom!=null){
Variant result = Dispatch.callN(mycom, "GetCPUid", new String[]{""});
System.out.print(result);
}
}
}