当前位置: 技术问答>java相关
300分求教解决方案(即将加分)
来源: 互联网 发布时间:2015-02-12
本文导语: 1,用java通过jni调用一段C++库 2,把C++库做成corba再调用他 问题:哪个方案性能好,实现快, 能否提供经验 | 方案一:性能好,实现快,但维护。 方案二:扩展性好。 你要很快实现,选用一。 要作的好...
1,用java通过jni调用一段C++库
2,把C++库做成corba再调用他
问题:哪个方案性能好,实现快,
能否提供经验
2,把C++库做成corba再调用他
问题:哪个方案性能好,实现快,
能否提供经验
|
方案一:性能好,实现快,但维护。
方案二:扩展性好。
你要很快实现,选用一。
要作的好,选二。
方案二:扩展性好。
你要很快实现,选用一。
要作的好,选二。
|
Java如何调用C/C++(JNI)
1. program Java source file loading Native method
//
//
// NativeDemo
// Author: huang_jc
// file name: NativeDemo.java
public class NativeDemo
{
int i;
int j;
public static void main(String args[])
{
NativeDemo ob = new NativeDemo();
ob.i = 10;
ob.j = ob.test();
System.out.println("this is ob.i:"+ob.i+"n");
System.out.println("this is ob.j:"+ob.j);
}
public native int test();
static
{
System.loadLibrary("NativeDemo");
}
}
2.Compile file NativeDemo.java
Javac NativeDemo.java
3.Use javah.exe to produce file NativeDemo.c and NativeDemo.h
a : javah NativeDemo to produce NativeDemo.h which is:
/* DO NOT EDIT THIS FILE - it is machine generated */
#include
/* Header for class NativeDemo */
#ifndef _Included_NativeDemo
#define _Included_NativeDemo
#pragma pack(4)
typedef struct ClassNativeDemo {
long i;
long j;
} ClassNativeDemo;
HandleTo(NativeDemo);
#pragma pack()
#ifdef __cplusplus
extern "C" {
#endif
extern long NativeDemo_test(struct HNativeDemo *);
#ifdef __cplusplus
}
#endif
#endif
b : use javah -stubs NativeDemo to produce NativeDemo.c which seems as:
/* DO NOT EDIT THIS FILE - it is machine generated */
#include
/* Stubs for class NativeDemo */
/* SYMBOL: "NativeDemo/test()I", Java_NativeDemo_test_stub */
__declspec(dllexport) stack_item *Java_NativeDemo_test_stub(stack_item *_P_,struct execenv *_EE_) {
extern long NativeDemo_test(void *);
_P_[0].i = NativeDemo_test(_P_[0].p);
return _P_ + 1;
}
4. Write your own implimentation of method test()
//file name test.c
#include
#include "nativedemo.h"
#include
long NativeDemo_test(HNativeDemo *this)
{
printf("hello:!n");
printf("this is in the native method!n");
return (unhand(this)->i)*2;
}
5. link NativeDemo.c and test.c to produce NativeDemo.dll
Use VC++5.0 tools :Cl.exe
Cl /GD NativeDemo.c test.c /LD
then we get NativeDemo.dll
NativeDemo.c
test.c
Generating Code...
/out:NativeDemo.dll
/dll
/implib:NativeDemo.lib
NativeDemo.obj
test.obj
Creating library NativeDemo.lib and object NativeDemo.ex
Press any key to continue
6.Run
java NativeDemo
we get the such result:
D:vj11usernative>java NativeDemo
hello:!
this is in the native method!
this is ob.i:10
this is ob.j:20
D:vj11usernative>
NOTE:
Do not forget this:
c:> set INCLUDE=d:javainclude;d:javawin32;%INCLUDE%
C:>set LIB =d:javalib;%LIB%
where d:java is the directory of your jdk
new version jdk1.2.1 :
With new jdk1.2.1 :
1.javac NativeDemo.java
2. javah NativeDemo to produce head file (You need not to javah -stubs NativeDemo to produce NativeDemo.c file),
You don't need the c file. Just the NativeDemo.h is sufficient!
3.Use VC++ produce a window dll project and add the NativeDemo.h to it.
then implement the function. All is OK!
NOTE: the data type conversion between java and c++.See jni.h for more information.
1. program Java source file loading Native method
//
//
// NativeDemo
// Author: huang_jc
// file name: NativeDemo.java
public class NativeDemo
{
int i;
int j;
public static void main(String args[])
{
NativeDemo ob = new NativeDemo();
ob.i = 10;
ob.j = ob.test();
System.out.println("this is ob.i:"+ob.i+"n");
System.out.println("this is ob.j:"+ob.j);
}
public native int test();
static
{
System.loadLibrary("NativeDemo");
}
}
2.Compile file NativeDemo.java
Javac NativeDemo.java
3.Use javah.exe to produce file NativeDemo.c and NativeDemo.h
a : javah NativeDemo to produce NativeDemo.h which is:
/* DO NOT EDIT THIS FILE - it is machine generated */
#include
/* Header for class NativeDemo */
#ifndef _Included_NativeDemo
#define _Included_NativeDemo
#pragma pack(4)
typedef struct ClassNativeDemo {
long i;
long j;
} ClassNativeDemo;
HandleTo(NativeDemo);
#pragma pack()
#ifdef __cplusplus
extern "C" {
#endif
extern long NativeDemo_test(struct HNativeDemo *);
#ifdef __cplusplus
}
#endif
#endif
b : use javah -stubs NativeDemo to produce NativeDemo.c which seems as:
/* DO NOT EDIT THIS FILE - it is machine generated */
#include
/* Stubs for class NativeDemo */
/* SYMBOL: "NativeDemo/test()I", Java_NativeDemo_test_stub */
__declspec(dllexport) stack_item *Java_NativeDemo_test_stub(stack_item *_P_,struct execenv *_EE_) {
extern long NativeDemo_test(void *);
_P_[0].i = NativeDemo_test(_P_[0].p);
return _P_ + 1;
}
4. Write your own implimentation of method test()
//file name test.c
#include
#include "nativedemo.h"
#include
long NativeDemo_test(HNativeDemo *this)
{
printf("hello:!n");
printf("this is in the native method!n");
return (unhand(this)->i)*2;
}
5. link NativeDemo.c and test.c to produce NativeDemo.dll
Use VC++5.0 tools :Cl.exe
Cl /GD NativeDemo.c test.c /LD
then we get NativeDemo.dll
NativeDemo.c
test.c
Generating Code...
/out:NativeDemo.dll
/dll
/implib:NativeDemo.lib
NativeDemo.obj
test.obj
Creating library NativeDemo.lib and object NativeDemo.ex
Press any key to continue
6.Run
java NativeDemo
we get the such result:
D:vj11usernative>java NativeDemo
hello:!
this is in the native method!
this is ob.i:10
this is ob.j:20
D:vj11usernative>
NOTE:
Do not forget this:
c:> set INCLUDE=d:javainclude;d:javawin32;%INCLUDE%
C:>set LIB =d:javalib;%LIB%
where d:java is the directory of your jdk
new version jdk1.2.1 :
With new jdk1.2.1 :
1.javac NativeDemo.java
2. javah NativeDemo to produce head file (You need not to javah -stubs NativeDemo to produce NativeDemo.c file),
You don't need the c file. Just the NativeDemo.h is sufficient!
3.Use VC++ produce a window dll project and add the NativeDemo.h to it.
then implement the function. All is OK!
NOTE: the data type conversion between java and c++.See jni.h for more information.
|
那就得用corba了。
具体怎么实现光靠几个例子是不够的。
以前我买到过一本将C++编corba的书,但不知现在还有吗。
具体怎么实现光靠几个例子是不够的。
以前我买到过一本将C++编corba的书,但不知现在还有吗。
|
用CORBA还要配服务器,如果只是用到少量的函数,就用JNI吧
挺方便的。
挺方便的。
|
up
|
jni实现相对简单
|
还好。