C++ JNI本地引用表溢出

Question

我遇到內存問題。

這是我的代碼。

JNICommunicator.cpp

const char *JNICommunicator::changeStringToUTF8(const char* str) 
{ 
    JniMethodInfo t; 
    JniHelper::getStaticMethodInfo(t, JNIPakageName, "changeStringToUTF8", "([B)Ljava/lang/String;"); 
    jbyteArray arr = (t.env)->NewByteArray(strlen(str)); 
    (t.env)->SetByteArrayRegion(arr,0,strlen(str), (const jbyte*)str); 
    jsize arrSize = t.env->GetArrayLength(arr); 
    //jbyte *pbyte = (t.env)->GetByteArrayElements(arr, 0); 
    jstring returnValue = (jstring)t.env->CallStaticObjectMethod(t.classID,t.methodID,arr); 
    // Release 
    //t.env->ReleaseByteArrayElements(arr, pbyte, 0); 
    t.env->DeleteLocalRef(arr); 
    t.env->DeleteLocalRef(t.classID); 
    return t.env->GetStringUTFChars(returnValue,0); 
} 

JNICommunicator.java

public static String changeStringToUTF8(byte[] arr) throws Exception 
{  String ansi = new String(arr, "EUC-KR"); 
    byte[] utf = ansi.getBytes("UTF-8"); 
    String ret = new String(utf, "UTF-8");  
    return ret; 
} 

，這裏是日誌。

02-07 12:53:04.195: E/dalvikvm(27764): JNI ERROR (app bug): local reference table overflow (max=512) 
02-07 12:53:04.195: W/dalvikvm(27764): JNI local reference table (0x7a5c1d78) dump: 
02-07 12:53:04.195: W/dalvikvm(27764): Last 10 entries (of 512): 
02-07 12:53:04.195: W/dalvikvm(27764):  511: 0x4243bf10 java.lang.String "다" 
02-07 12:53:04.195: W/dalvikvm(27764):  510: 0x419be8d0 java.lang.Class<java.util.regex.Matcher> 
02-07 12:53:04.195: W/dalvikvm(27764):  509: 0x4243c160 java.lang.String "fonts/NanumGothi... (21 chars) 
02-07 12:53:04.195: W/dalvikvm(27764):  508: 0x42443240 java.lang.String "다" 
02-07 12:53:04.195: W/dalvikvm(27764):  507: 0x4245f370 java.lang.String "졌" 
02-07 12:53:04.195: W/dalvikvm(27764):  506: 0x424780d0 java.lang.String "는" 
02-07 12:53:04.195: W/dalvikvm(27764):  505: 0x41d7a540 java.lang.String "그" 
02-07 12:53:04.195: W/dalvikvm(27764):  504: 0x424a94a0 java.lang.String "다" 
02-07 12:53:04.195: W/dalvikvm(27764):  503: 0x424c2200 java.lang.String "뒤" 
02-07 12:53:04.195: W/dalvikvm(27764):  502: 0x424deb78 java.lang.String "난" 
02-07 12:53:04.195: W/dalvikvm(27764): Summary: 
02-07 12:53:04.195: W/dalvikvm(27764):   3 of java.lang.Class (3 unique instances) 
02-07 12:53:04.195: W/dalvikvm(27764):  509 of java.lang.String (509 unique instances) 
02-07 12:53:04.195: E/dalvikvm(27764): Failed adding to JNI local ref table (has 512 entries) 

我認爲返回值需要在cpp文件中釋放內存..請幫忙！

Answer 1

使用GetStringUTFChars解決。

const char *JNICommunicator::changeStringToUTF8(const char* str) 
{ 
    JniMethodInfo t; 
    JniHelper::getStaticMethodInfo(t, JNIPakageName, "changeStringToUTF8", "([B)Ljava/lang/String;"); 
    jbyteArray arr = (t.env)->NewByteArray(strlen(str)); 
    (t.env)->SetByteArrayRegion(arr,0,strlen(str), (const jbyte*)str); 
    jsize arrSize = t.env->GetArrayLength(arr); 
    //jbyte *pbyte = (t.env)->GetByteArrayElements(arr, 0); 
    jstring returnValue = (jstring)t.env->CallStaticObjectMethod(t.classID,t.methodID,arr); 
    const char *nativeString = (t.env)->GetStringUTFChars(returnValue, 0); 
    // Release 
    //t.env->ReleaseByteArrayElements(arr, pbyte, 0); 
    t.env->DeleteLocalRef(arr); 
    t.env->DeleteLocalRef(t.classID); 
    t.env->DeleteLocalRef(returnValue); 
    return nativeString; 
} 

通過使用GetStringUTFChars獲取const char *並釋放jstring。