#include <jni.h> #include "com_test_Test.h" #include <stdio.h> #include <stdlib.h> #include <strings.h> //获取字符串 JNIEXPORT void JNICALL Java_com_test_Test_sayHello(JNIEnv * env, jobject obj, jstring s) { char * str = (char *) (*env)->GetStringUTFChars(env, s, 0); printf("/n c-string: hello - %s", str); } //获取，返回int JNIEXPORT jint JNICALL Java_com_test_Test_add(JNIEnv * env, jobject obj, jint a, jint b) { int i = a; int j = b; printf("/n c-int: %d - %d", i, j); char str[256]; sprintf(str, "%d", i + j); return (jint) i + j; } //获取，返回float JNIEXPORT jfloat JNICALL Java_com_test_Test_getFloat(JNIEnv * env, jobject obj, jfloat f) { float fl = f; printf("/n c-float: ?", fl); fl = 200.555; return (jfloat) fl; } //获取，返回 double JNIEXPORT jdouble JNICALL Java_com_test_Test_getDouble(JNIEnv * env, jobject obj, jdouble dou) { double d = dou; printf("/n c-double: ?", d); d = 800.88; return (jdouble) d; } //获取，返回boolean JNIEXPORT jboolean JNICALL Java_com_test_Test_getBoolean(JNIEnv * env, jobject obj, jboolean bool) { unsigned char b = bool; printf("/n c-boolean: %lu ", b); if (b) { printf("true"); } else { printf("false"); } b = 1; return (jboolean) b; } //获取，返回 string JNIEXPORT jstring JNICALL Java_com_test_Test_getString(JNIEnv * env, jobject obj, jstring s) { char * st = (char *) (*env)->GetStringUTFChars(env, s, 0); printf("/n c-string: %s", st); char * str = "hello wang wu!"; jstring rtn; rtn = (*env)->NewStringUTF(env, str); return rtn; } //获取，返回 string [] JNIEXPORT jobjectArray JNICALL Java_com_test_Test_getStringArray(JNIEnv * env, jobject obj, jobjectArray arr) { int len = (*env)->GetArrayLength(env, arr); printf("/n c-stringArray :"); int i = 0; for (i = 0; i < len; i++) { jobject obj = (*env)->GetObjectArrayElement(env, arr, i); jstring str = (jstring) obj; const char * szStr = (*env)->GetStringUTFChars(env, str, 0); printf(" %d-%s ", i, szStr); (*env)->ReleaseStringChars(env, str, szStr); } //-----返回---- jstring str; jobjectArray args = 0; jsize size = 5; char* sa[] = { "Hello,", "world!", "zhang", "san", "yuang" }; int j = 0; jclass objClass = (*env)->FindClass(env, "java/lang/String"); args = (*env)->NewObjectArray(env, size, objClass, 0); for (j = 0; j < size; j++) { str = (*env)->NewStringUTF(env, sa[j]); (*env)->SetObjectArrayElement(env, args, j, str); } return args; } #include <jni.h> #include "com_test_Test.h" #include <stdio.h> #include <stdlib.h> #include <strings.h> //获取字符串 JNIEXPORT void JNICALL Java_com_test_Test_sayHello(JNIEnv * env, jobject obj, jstring s) { char * str = (char *) (*env)->GetStringUTFChars(env, s, 0); printf("/n c-string: hello - %s", str); } //获取，返回int JNIEXPORT jint JNICALL Java_com_test_Test_add(JNIEnv * env, jobject obj, jint a, jint b) { int i = a; int j = b; printf("/n c-int: %d - %d", i, j); char str[256]; sprintf(str, "%d", i + j); return (jint) i + j; } //获取，返回float JNIEXPORT jfloat JNICALL Java_com_test_Test_getFloat(JNIEnv * env, jobject obj, jfloat f) { float fl = f; printf("/n c-float: ?", fl); fl = 200.555; return (jfloat) fl; } //获取，返回 double JNIEXPORT jdouble JNICALL Java_com_test_Test_getDouble(JNIEnv * env, jobject obj, jdouble dou) { double d = dou; printf("/n c-double: ?", d); d = 800.88; return (jdouble) d; } //获取，返回boolean JNIEXPORT jboolean JNICALL Java_com_test_Test_getBoolean(JNIEnv * env, jobject obj, jboolean bool) { unsigned char b = bool; printf("/n c-boolean: %lu ", b); if (b) { printf("true"); } else { printf("false"); } b = 1; return (jboolean) b; } //获取，返回 string JNIEXPORT jstring JNICALL Java_com_test_Test_getString(JNIEnv * env, jobject obj, jstring s) { char * st = (char *) (*env)->GetStringUTFChars(env, s, 0); printf("/n c-string: %s", st); char * str = "hello wang wu!"; jstring rtn; rtn = (*env)->NewStringUTF(env, str); return rtn; } //获取，返回 string [] JNIEXPORT jobjectArray JNICALL Java_com_test_Test_getStringArray(JNIEnv * env, jobject obj, jobjectArray arr) { int len = (*env)->GetArrayLength(env, arr); printf("/n c-stringArray :"); int i = 0; for (i = 0; i < len; i++) { jobject obj = (*env)->GetObjectArrayElement(env, arr, i); jstring str = (jstring) obj; const char * szStr = (*env)->GetStringUTFChars(env, str, 0); printf(" %d-%s ", i, szStr); (*env)->ReleaseStringChars(env, str, szStr); } //-----返回---- jstring str; jobjectArray args = 0; jsize size = 5; char* sa[] = { "Hello,", "world!", "zhang", "san", "yuang" }; int j = 0; jclass objClass = (*env)->FindClass(env, "java/lang/String"); args = (*env)->NewObjectArray(env, size, objClass, 0); for (j = 0; j < size; j++) { str = (*env)->NewStringUTF(env, sa[j]); (*env)->SetObjectArrayElement(env, args, j, str); } return args; } 下面是Test.java Java代码 package com.test; public class Test { private native void sayHello(String str); private native int add(int a, int b); private native float getFloat(float f); private native double getDouble(double d); private native boolean getBoolean(boolean b); private native String getString(String str); private native String[] getStringArray(String[] sa); static { System.loadLibrary("Test"); } public static void main(String[] args) { Test test = new Test(); test.sayHello("zhang san"); System.out.println("int --> " + test.add(10, 20)); System.out.println("float --> " + test.getFloat((float) 20.123)); System.out.println("double --> " + test.getDouble(100.369)); System.out.println("boolean --> " + test.getBoolean(true)); System.out.println("string --> " + test.getString("wang Wu")); String[] ss = { "hello", "-", "zhang", "san" }; Object[] obj = test.getStringArray(ss); System.out.print("string[]--> "); for (Object object : obj) { System.out.print(object + " "); } } } package com.test; public class Test { private native void sayHello(String str); private native int add(int a, int b); private native float getFloat(float f); private native double getDouble(double d); private native boolean getBoolean(boolean b); private native String getString(String str); private native String[] getStringArray(String[] sa); static { System.loadLibrary("Test"); } public static void main(String[] args) { Test test = new Test(); test.sayHello("zhang san"); System.out.println("int --> " + test.add(10, 20)); System.out.println("float --> " + test.getFloat((float) 20.123)); System.out.println("double --> " + test.getDouble(100.369)); System.out.println("boolean --> " + test.getBoolean(true)); System.out.println("string --> " + test.getString("wang Wu")); String[] ss = { "hello", "-", "zhang", "san" }; Object[] obj = test.getStringArray(ss); System.out.print("string[]--> "); for (Object object : obj) { System.out.print(object + " "); } } } ++++++++++++++++++++++++++++++++++++++++++++++++++ 上面类型转换没有一个一个去试，应该都是可以的 ++++++++++++++++++++++++++++++++++++++++++++++++++ 2：JNI 乱码解决方案 顺便再转一个JNI相关的：jni乱码解决方案 http://www.wangchao.net.cn/bbsdetail_57022.html Java代码： Java代码 /* * javactransfer.java * By dpwu * e-mail：dpwu_js@sina.com.cn */ public class javactransfer { public String hypotenuse(String send_buf,String recv_buf,int errno) { return hypotenuse0(send_buf,recv_buf,errno); } private native String hypotenuse0(String send_buf,String recv_buf,int errno); static { System.loadLibrary("javactransfer");//调用dll } public static void main( String[] args ) { javactransfer obj= new javactransfer(); System.out.println(""); System.out.println(""); System.out.println(" begin!"); System.out.println(""); System.out.println(""); String javasend="发送中文chinese!"; System.out.println(" java send:"+"["+javasend+"]"); String javarecv=obj.hypotenuse("teststr",javasend,1); //javasend传含有中文字符串给C //javarecv接受C含有中的文字符串 System.out.println(" java recv:"+"["+javarecv+"]"); System.out.println(""); System.out.println(""); System.out.println(" end!"); } } /* * javactransfer.java * By dpwu * e-mail：dpwu_js@sina.com.cn */ public class javactransfer { public String hypotenuse(String send_buf,String recv_buf,int errno) { return hypotenuse0(send_buf,recv_buf,errno); } private native String hypotenuse0(String send_buf,String recv_buf,int errno); static { System.loadLibrary("javactransfer");//调用dll } public static void main( String[] args ) { javactransfer obj= new javactransfer(); System.out.println(""); System.out.println(""); System.out.println(" begin!"); System.out.println(""); System.out.println(""); String javasend="发送中文chinese!"; System.out.println(" java send:"+"["+javasend+"]"); String javarecv=obj.hypotenuse("teststr",javasend,1); //javasend传含有中文字符串给C //javarecv接受C含有中的文字符串 System.out.println(" java recv:"+"["+javarecv+"]"); System.out.println(""); System.out.println(""); System.out.println(" end!"); } } C实现代码为： C代码 /* * javactransfer.c * By dpwu * e-mail：dpwu_js@sina.com.cn */ #include <windows.h> #include "javactransfer.h"//通过javah –jni javactransfer 生成 #include <stdio.h> #include "stdlib.h" #include "string.h" char* jstringToWindows( JNIEnv *env, jstring jstr ); jstring WindowsTojstring( JNIEnv* env, char* str ); JNIEXPORT jstring JNICALL Java_javactransfer_hypotenuse0(JNIEnv *env,jobject obj,jstring send_buf,jstring recv_buf,jint errno) { char * Buf_Return; Buf_Return = (char*)malloc(1024); const char * recvtest = jstringToWindows( env, recv_buf ); /*上句recvtest接收Java传过来的中文字符串正确,如果改为下句,则出现乱码: const char * recvtest = (*env)->GetStringUTFChars( env,recv_buf,0); */ printf( " c recv :[%s]/n" , recvtest); sprintf(Buf_Return,"接收中文chinese!"); printf( "/n/n/n c send :[%s]/n" , Buf_Return); recv_buf = WindowsTojstring(env ,Buf_Return); /*上句recv_buf传windows本地C中含有中文字符串给Java正确;如果改为下句出现乱码: recv_buf = (*env)->NewStringUTF( env, Buf_Return ); */ return recv_buf; } char* jstringToWindows( JNIEnv *env, jstring jstr ) { int length = (*env)->GetStringLength(env,jstr ); const jchar* jcstr = (*env)->GetStringChars(env,jstr, 0 ); char* rtn = (char*)malloc( length*2+1 ); int size = 0; size = WideCharToMultiByte( CP_ACP, 0, (LPCWSTR)jcstr, length, rtn,(length*2+1), NULL, NULL ); if( size <= 0 ) return NULL; (*env)->ReleaseStringChars(env,jstr, jcstr ); rtn[size] = 0; return rtn; } jstring WindowsTojstring( JNIEnv* env, char* str ) { jstring rtn = 0; int slen = strlen(str); unsigned short* buffer = 0; if( slen == 0 ) rtn = (*env)->NewStringUTF(env,str ); else { int length = MultiByteToWideChar( CP_ACP, 0, (LPCSTR)str, slen, NULL, 0 ); buffer = malloc( length*2 + 1 ); if( MultiByteToWideChar( CP_ACP, 0, (LPCSTR)str, slen, (LPWSTR)buffer, length ) >0 ) rtn = (*env)->NewString( env, (jchar*)buffer, length ); } if( buffer ) free( buffer ); return rtn; } /* * javactransfer.c * By dpwu * e-mail：dpwu_js@sina.com.cn */ #include <windows.h> #include "javactransfer.h"//通过javah –jni javactransfer 生成 #include <stdio.h> #include "stdlib.h" #include "string.h" char* jstringToWindows( JNIEnv *env, jstring jstr ); jstring WindowsTojstring( JNIEnv* env, char* str ); JNIEXPORT jstring JNICALL Java_javactransfer_hypotenuse0(JNIEnv *env,jobject obj,jstring send_buf,jstring recv_buf,jint errno) { char * Buf_Return; Buf_Return = (char*)malloc(1024); const char * recvtest = jstringToWindows( env, recv_buf ); /*上句recvtest接收Java传过来的中文字符串正确,如果改为下句,则出现乱码: const char * recvtest = (*env)->GetStringUTFChars( env,recv_buf,0); */ printf( " c recv :[%s]/n" , recvtest); sprintf(Buf_Return,"接收中文chinese!"); printf( "/n/n/n c send :[%s]/n" , Buf_Return); recv_buf = WindowsTojstring(env ,Buf_Return); /*上句recv_buf传windows本地C中含有中文字符串给Java正确;如果改为下句出现乱码: recv_buf = (*env)->NewStringUTF( env, Buf_Return ); */ return recv_buf; } char* jstringToWindows( JNIEnv *env, jstring jstr ) { int length = (*env)->GetStringLength(env,jstr ); const jchar* jcstr = (*env)->GetStringChars(env,jstr, 0 ); char* rtn = (char*)malloc( length*2+1 ); int size = 0; size = WideCharToMultiByte( CP_ACP, 0, (LPCWSTR)jcstr, length, rtn,(length*2+1), NULL, NULL ); if( size <= 0 ) return NULL; (*env)->ReleaseStringChars(env,jstr, jcstr ); rtn[size] = 0; return rtn; } jstring WindowsTojstring( JNIEnv* env, char* str ) { jstring rtn = 0; int slen = strlen(str); unsigned short* buffer = 0; if( slen == 0 ) rtn = (*env)->NewStringUTF(env,str ); else { int length = MultiByteToWideChar( CP_ACP, 0, (LPCSTR)str, slen, NULL, 0 ); buffer = malloc( length*2 + 1 ); if( MultiByteToWideChar( CP_ACP, 0, (LPCSTR)str, slen, (LPWSTR)buffer, length ) >0 ) rtn = (*env)->NewString( env, (jchar*)buffer, length ); } if( buffer ) free( buffer ); return rtn; } C++实现代码为: C++代码 /* * javactransfer.cpp * By dpwu * e-mail：dpwu_js@sina.com.cn */ #include <windows.h> #include "javactransfer.h"//通过javah –jni javactransfer 生成 #include <stdio.h> #include "stdlib.h" #include "string.h" char* jstringToWindows( JNIEnv *env, jstring jstr ); jstring WindowsTojstring( JNIEnv* env, char* str ); JNIEXPORT jstring JNICALL Java_javactransfer_hypotenuse0(JNIEnv *env,jobject obj,jstring send_buf,jstring recv_buf,jint _tperrno) { char * Buf_Return; Buf_Return = (char*)malloc(1024); const char * ctest = jstringToWindows( env, recv_buf ); /* 如果把上句改为下句，C接收Java字符串时将出现乱码： const char *ctest = (env)->GetStringUTFChars( recv_buf , 0); */ printf( " c recv :[%s]/n" , ctest); sprintf(Buf_Return,"接收中文chinese!"); printf( "/n/n/n c send :[%s]/n" , Buf_Return); recv_buf = WindowsTojstring(env ,Buf_Return); /*上句执行正确,如果把上句换成下句,Java在接收C字符串时出现乱码 recv_buf = (env)->NewStringUTF(Buf_Return); */ return recv_buf; } char* jstringToWindows( JNIEnv *env, jstring jstr ) { int length = (env)->GetStringLength(jstr ); const jchar* jcstr = (env)->GetStringChars(jstr, 0 ); char* rtn = (char*)malloc( length*2+1 ); int size = 0; size = WideCharToMultiByte( CP_ACP, 0, (LPCWSTR)jcstr, length, rtn,(length*2+1), NULL, NULL ); if( size <= 0 ) return NULL; (env)->ReleaseStringChars(jstr, jcstr ); rtn[size] = 0; return rtn; } jstring WindowsTojstring( JNIEnv* env, char* str ) { jstring rtn = 0; int slen = strlen(str); unsigned short * buffer = 0; if( slen == 0 ) rtn = (env)->NewStringUTF(str ); else { int length = MultiByteToWideChar( CP_ACP, 0, (LPCSTR)str, slen, NULL, 0 ); buffer = (unsigned short *)malloc( length*2 + 1 ); if( MultiByteToWideChar( CP_ACP, 0, (LPCSTR)str, slen, (LPWSTR)buffer, length ) >0 ) rtn = (env)->NewString( (jchar*)buffer, length ); } if( buffer ) free( buffer ); return rtn; } 本文来自博客，转载请标明出处：http://blog.csdn.net/ACCP_2008123456/archive/2010/02/23/5318967.aspx
