目前上期技术CTP系统提供的API版本是C++版本
SWIG是一个能将C/C++接口转换为其他语言的工具，目前可以支持Python,Java,R等语言。
本文主要介绍Windows 32/64位平台下利用Swig工具将CTP C++接口API转换为Java可调用的接口。
1、从CTP官网下载最新API包，包中包含32位和64位。API文件包清单：
2、下载安装Swig软件：
3、在API文件包中创建thostapi.i 和various.i文件，thostapi.i是一个接口文件，用于告诉swig为哪些类和方法创建接口
various.i是用于将C++接口中的数组参数转换为java 的Array的工具类
%module(directors="") thosttraderapi
%include "various.i"
%apply char **STRING_ARRAY { char *ppInstrumentID[] }
%{
#include "ThostFtdcMdApi.h"
#include "ThostFtdcTraderApi.h"
%}
%feature("director") CThostFtdcMdSpi;
%include "ThostFtdcUserApiDataType.h"
%include "ThostFtdcUserApiStruct.h"
%include "ThostFtdcMdApi.h"
%feature("director") CThostFtdcTraderSpi;
%include "ThostFtdcTraderApi.h"
4、生成java接口：
在当前文件夹创建src/ctp文件夹用于放置生成的java文件
..\..\swigwin-2.0.\swig.exe -c++ -java -package ctp.thosttraderapi -outdir src -o thosttraderapi_wrap.cpp thostapi.i
运行完成之后，可在当前文件夹中看到用于包装原来C++接口的文件：
5、通过C++得到java可调用的动态库
创建一个C++工程，应用程序类型选择DLL,将以下文件添加到工程中去:
将dk目录\Java\jdk1.8.0_111\include下的jni.h和win32文件夹下的jni_md.h, jawt_md.h一共三个文件
拷贝到安装vs的include目录底下\Microsoft Visual Studio 12.0\VC\include。
因为thosttraderapi_wrap.cpp文件中包含了<jni.h>,是用于生成Java可调用接口的库文件。
将如下8个函数注释掉，这几个函数中涉及到将字符串转换为char类型，有问题：
Java_ctp_thosttraderapi_thosttradeapiJNI_THOST_1FTDC_1VTC_1BankBankToFuture_1get
Java_ctp_thosttraderapi_thosttradeapiJNI_THOST_1FTDC_1VTC_1BankFutureToBank_1get
Java_ctp_thosttraderapi_thosttradeapiJNI_THOST_1FTDC_1VTC_1FutureBankToFuture_1get
Java_ctp_thosttraderapi_thosttradeapiJNI_THOST_1FTDC_1VTC_1FutureFutureToBank_1get
Java_ctp_thosttraderapi_thosttradeapiJNI_THOST_1FTDC_1FTC_1BankLaunchBankToBroker_1get
Java_ctp_thosttraderapi_thosttradeapiJNI_THOST_1FTDC_1FTC_1BrokerLaunchBankToBroker_1get
Java_ctp_thosttraderapi_thosttradeapiJNI_THOST_1FTDC_1FTC_1BankLaunchBrokerToBank_1get
Java_ctp_thosttraderapi_thosttradeapiJNI_THOST_1FTDC_1FTC_1BrokerLaunchBrokerToBank_1get
之后进行编译，生成java可调用的动态库文件thosttraderapi_wrap.dll：
6、创建java项目，将三个动态库和之前生成的src/ctp包拷贝到项目，并加载动态库进来：
到此java API制作完成，可以进行java开发了
附various.i:
/*
* char **STRING_ARRAY typemaps.
* These typemaps are for C String arrays which are NULL terminated.
* char *values[] = { "one", "two", "three", NULL }; // note NULL
* char ** is mapped to a Java String[].
*
* Example usage wrapping:
* %apply char **STRING_ARRAY { char **input };
* char ** foo(char **input);
*
* Java usage:
* String numbers[] = { "one", "two", "three" };
* String[] ret = modulename.foo( numbers };
*/
%typemap(jni) char **STRING_ARRAY "jobjectArray"
%typemap(jtype) char **STRING_ARRAY "String[]"
%typemap(jstype) char **STRING_ARRAY "String[]"
%typemap(in) char **STRING_ARRAY (jint size) {
int i = ;
size = JCALL1(GetArrayLength, jenv, $input);
#ifdef __cplusplus
$ = new char*[size+];
#else
$ = (char **)calloc(size+, sizeof(char *));
#endif
for (i = ; i<size; i++) {
jstring j_string = (jstring)JCALL2(GetObjectArrayElement, jenv, $input, i);
const char *c_string = JCALL2(GetStringUTFChars, jenv, j_string, );
#ifdef __cplusplus
$[i] = new char [strlen(c_string)+];
#else
$[i] = (char *)calloc(strlen(c_string)+, sizeof(const char *));
#endif
strcpy($[i], c_string);
JCALL2(ReleaseStringUTFChars, jenv, j_string, c_string);
JCALL1(DeleteLocalRef, jenv, j_string);
}
$[i] = ;
} %typemap(freearg) char **STRING_ARRAY {
int i;
for (i=; i<size$argnum-; i++)
#ifdef __cplusplus
delete[] $[i];
delete[] $;
#else
free($[i]);
free($);
#endif
} %typemap(out) char **STRING_ARRAY {
int i;
int len=;
jstring temp_string;
const jclass clazz = JCALL1(FindClass, jenv, "java/lang/String"); while ($[len]) len++;
jresult = JCALL3(NewObjectArray, jenv, len, clazz, NULL);
/* exception checking omitted */ for (i=; i<len; i++) {
temp_string = JCALL1(NewStringUTF, jenv, *result++);
JCALL3(SetObjectArrayElement, jenv, jresult, i, temp_string);
JCALL1(DeleteLocalRef, jenv, temp_string);
}
} %typemap(javain) char **STRING_ARRAY "$javainput"
%typemap(javaout) char **STRING_ARRAY {
return $jnicall;
} /*
* char **STRING_OUT typemaps.
* These are typemaps for returning strings when using a C char ** parameter type.
* The returned string appears in the 1st element of the passed in Java String array.
*
* Example usage wrapping:
* void foo(char **string_out);
*
* Java usage:
* String stringOutArray[] = { "" };
* modulename.foo(stringOutArray);
* System.out.println( stringOutArray[0] );
*/
%typemap(jni) char **STRING_OUT "jobjectArray"
%typemap(jtype) char **STRING_OUT "String[]"
%typemap(jstype) char **STRING_OUT "String[]"
%typemap(javain) char **STRING_OUT "$javainput" %typemap(in) char **STRING_OUT($*1_ltype temp) {
if (!$input) {
SWIG_JavaThrowException(jenv, SWIG_JavaNullPointerException, "array null");
return $null;
}
if (JCALL1(GetArrayLength, jenv, $input) == ) {
SWIG_JavaThrowException(jenv, SWIG_JavaIndexOutOfBoundsException, "Array must contain at least 1 element");
return $null;
}
$ = &temp;
} %typemap(argout) char **STRING_OUT {
jstring jnewstring = NULL;
if($) {
jnewstring = JCALL1(NewStringUTF, jenv, *$);
}
JCALL3(SetObjectArrayElement, jenv, $input, , jnewstring);
} /*
* char *BYTE typemaps.
* These are input typemaps for mapping a Java byte[] array to a C char array.
* Note that as a Java array is used and thus passeed by reference, the C routine
* can return data to Java via the parameter.
*
* Example usage wrapping:
* void foo(char *array);
*
* Java usage:
* byte b[] = new byte[20];
* modulename.foo(b);
*/
%typemap(jni) char *BYTE "jbyteArray"
%typemap(jtype) char *BYTE "byte[]"
%typemap(jstype) char *BYTE "byte[]"
%typemap(in) char *BYTE {
$ = (char *) JCALL2(GetByteArrayElements, jenv, $input, );
} %typemap(argout) char *BYTE {
JCALL3(ReleaseByteArrayElements, jenv, $input, (jbyte *) $, );
} %typemap(javain) char *BYTE "$javainput" /* Prevent default freearg typemap from being used */
%typemap(freearg) char *BYTE ""