Android 从JNI中传入UTF8 的字符到Java

    技术2024-08-21  70

    从JNI中传入UTF8 的字符乱码的问题,困扰了我很久了哇,今天终于找到解决办法了。

    由于env->NewStringUTF支持的是 Modified UTF-8,所以这个API不能用来从JNI

    中传入标准的UTF8字符到Java。

    //ReturnUTF8.java   view plaincopy to clipboardprint?   public class ReturnUTF8 {   static {   System.loadLibrary("ReturnUTF8Jni");   }   public static native byte[] method1();   public static native Object method2();   public static void main(String[] args) {   try {   byte[] buffer = ReturnUTF8.method1();   String s1 = new String(buffer, "UTF-8");   System.out.println("s1 = " + s1);   String s2 = ReturnUTF8.method2().toString();   System.out.println("s2 = " + s2);   } catch (java.io.UnsupportedEncodingException e) {   e.printStackTrace();   }   }   }   public class   ReturnUTF8 {   static {   System.loadLibrary("ReturnUTF8Jni");   }   public static native byte[] method1();   public static native Object method2();   public static void main(String[] args) {   try {   byte[] buffer = ReturnUTF8.method1();   String s1 = new String(buffer, "UTF-8");   System.out.println("s1 = " + s1);   String s2 = ReturnUTF8.method2().toString();   System.out.println("s2 = " + s2);   } catch (java.io.UnsupportedEncodingException e) {   e.printStackTrace();   }   }   }  

     

    # javac ReturnUTF8.java

     

     

     

     

     

      # java ReturnUTF8

     

      

       这里会生成一个ReturnUTF8.h头文件

     

     

     

    //ReturnUTF8.cpp   view plaincopy to clipboardprint?   #include "ReturnUTF8.h"   JNIEXPORT jbyteArray JNICALL Java_ReturnUTF8_method1   (JNIEnv *env, jclass cls)   { jbyte buffer[] = /* UTF8 encoding buffer */   jbyteArray bytes = env->NewByteArray(sizeof(buffer));   env->SetByteArrayRegion(bytes, 0, sizeof(buffer), buffer);   return bytes;   }   JNIEXPORT jbyteArray JNICALL Java_ReturnUTF8_method2   (JNIEnv *env, jclass cls)   {   jbyte buffer[] = /* UTF8 encoding buffer */   jbyteArray bytes = env->NewByteArray(sizeof(buffer));   env->SetByteArrayRegion(bytes, 0, sizeof(buffer), buffer);   jchar encoding_name[] = { 'U', 'T', 'F', '-', '8', '' };   jstring encoding = env->NewString(encoding_name, 5);   jclass theStringClass = env->FindClass("Ljava/lang/String;");   jmethodID mid = env->GetMethodID(theStringClass, "", "([BLjava/lang/String;)V");   jobject result = env->NewObject(theStringClass, mid, bytes, encoding);   return result;   }   #include   "ReturnUTF8.h"   JNIEXPORT jbyteArray JNICALL Java_ReturnUTF8_method1   (JNIEnv *env, jclass cls)   {   jbyte buffer[] = /* UTF8 encoding buffer */   jbyteArray bytes = env->NewByteArray(sizeof(buffer));   env->SetByteArrayRegion(bytes, 0, sizeof(buffer), buffer);   return bytes;   }   JNIEXPORT jbyteArray JNICALL Java_ReturnUTF8_method2   (JNIEnv *env, jclass cls)   {   jbyte buffer[] = /* UTF8 encoding buffer */   jbyteArray bytes = env->NewByteArray(sizeof(buffer));   env->SetByteArrayRegion(bytes, 0, sizeof(buffer), buffer);   jchar encoding_name[] = { 'U', 'T', 'F', '-', '8', '' };   jstring encoding = env->NewString(encoding_name, 5);   jclass theStringClass = env->FindClass("Ljava/lang/String;");   jmethodID mid = env->GetMethodID(theStringClass, "",   "([BLjava/lang/String;)V");   jobject result = env->NewObject(theStringClass, mid, bytes,   encoding);   return result;   }  

     

    # g++ -shared -I /usr/lib/jvm/java-1.5.0-sun/include -I /usr/lib/jvm/java-1.5.0-sun/include/linux ReturnUTF8.cpp -o libReturnUTF8Jni.so

     

     

      # export LD_LIBRARY=.

      # java ReturnUTF8

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