Android - 从JNI中传入UTF8的字符到Java

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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。

我们有两种解决方法：

Java代码

ReturnUTF8.java

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

# javah ReturnUTF8

-> 这里会生成一个ReturnUTF8.h头文件

C++代码

ReturnUTF8.cpp

#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', '/0' }; jstring encoding = env->NewString(encoding_name, 5); jclass theStringClass = env->FindClass("java/lang/String"); jmethodID mid = env->GetMethodID(theStringClass, "<init>", "([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