1.在Android中java层提供了工具类:android.util.Base64;
里面都是静态方法,方便直接使用:
使用方法如下:
Java代码
- // Base64 编码:
- byte [] encode = Base64.encode("Hello, World".getBytes(), Base64.DEFAULT);
- String enc = new String(encode);
- Log.d("","base 64 encode = " + enc);
- // Base64 解码:
- byte [] result = Base64.decode("SGVsbG8sIFdvcmxk", Base64.DEFAULT);
- String res = new String(result);
- Log.d("", "base 64 result = " + res);
例子演示了将"Hello, World"编码成"SGVsbG8sIFdvcmxk",然后又解码回来。简单易懂。
2.对于ios来说,有google的提供的一个工具箱来解决。
网址:http://code.google.com/p/google-toolbox-for-mac/
需要从里面找出3个文件:GTMBase64.h,GTMBase64.m,GTMDefines.h
将这三个文件加入ios工程中即可使用了。
例如:
使用:
NSLog(@"%@", [selfencodeBase64:@"Hello, World"]);
NSLog(@"%@", [selfdecodeBase64:@"SGVsbG8sIFdvcmxk"]);
调用的自己封装的函数:
- (NSString *) encodeBase64:(NSString *) input{
NSData *data = [inputdataUsingEncoding:NSUTF8StringEncodingallowLossyConversion:YES];
data = [GTMBase64 encodeData:data];
NSString *base64String = [[NSStringalloc] initWithData:dataencoding:NSUTF8StringEncoding];
return base64String;
}
- (NSString *) decodeBase64:(NSString *) input{
NSData *data = [inputdataUsingEncoding:NSUTF8StringEncodingallowLossyConversion:YES];
data = [GTMBase64 decodeData:data];
NSString *string = [[NSStringalloc] initWithData:dataencoding:NSUTF8StringEncoding];
return string;
}
3.在Android中,我们也可以将base64的编解码算法放到jni中,这样也是比较方便的。
对应的c中算法如下:
C代码
- #include "com_example_base64test_JniTest.h"
- #include <stdlib.h>
- #include <android/log.h> // 这个是输出LOG所用到的函数所在的路径
- #define LOG_TAG "JNILOG" // 这个是自定义的LOG的标识
- #undef LOG // 取消默认的LOG
- #define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG,LOG_TAG,__VA_ARGS__) // 定义LOG类型
- #define LOGI(...) __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__) // 定义LOG类型
- #define LOGW(...) __android_log_print(ANDROID_LOG_WARN,LOG_TAG,__VA_ARGS__) // 定义LOG类型
- #define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__) // 定义LOG类型
- #define LOGF(...) __android_log_print(ANDROID_LOG_FATAL,LOG_TAG,__VA_ARGS__) // 定义LOG类型
- const char base[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
- char* base64_encode(const char* data, int data_len);
- char *base64_decode(const char* data, int data_len);
- static char find_pos(char ch);
- /*
- * Class: com_example_base64test_JniTest
- * Method: encode
- * Signature: (Ljava/lang/String;)Ljava/lang/String;
- */
- JNIEXPORT jstring JNICALL Java_com_example_base64test_JniTest_encode
- (JNIEnv *env, jobject obj, jstring string)
- {
- // 先将jstring转换成char*
- char *t = 0;
- jclass clsstring = env->FindClass("java/lang/String");
- jstring strencode = env->NewStringUTF("utf-8");
- jmethodID mid = env->GetMethodID(clsstring, "getBytes", "(Ljava/lang/String;)[B");
- jbyteArray barr= (jbyteArray)env->CallObjectMethod(string, mid, strencode);
- jsize alen = env->GetArrayLength(barr);
- jbyte* ba = env->GetByteArrayElements(barr, JNI_FALSE);
- if (alen > 0)
- {
- t = (char*)malloc(alen + 1);
- memcpy(t, ba, alen);
- t[alen] = 0;
- }
- env->ReleaseByteArrayElements(barr, ba, 0);
- // 此时的t里面有了jstring的内容
- int i = 0;
- int j = strlen(t);
- char *enc = base64_encode(t, j);
- int len = strlen(enc);
- char *dec = base64_decode(enc, len);
- LOGD("\noriginal: %s\n", t);
- LOGD("\nencoded : %s\n", enc);
- LOGD("\ndecoded : %s\n", dec);
- free(enc);
- free(dec);
- // 将base64编码后的char转换成jstring返回给java层
- // jclass strClass = env->FindClass("Ljava/lang/String;");
- jclass strClass = env->FindClass("java/lang/String");
- jmethodID ctorID = env->GetMethodID(strClass, "<init>", "([BLjava/lang/String;)V");
- jbyteArray bytes = env->NewByteArray(strlen(enc));
- env->SetByteArrayRegion(bytes, 0, strlen(enc), (jbyte*)enc);
- jstring encoding = env->NewStringUTF("UTF-8");
- // jchar encoding_name[] = { ‘U‘, ‘T‘, ‘F‘, ‘-‘, ‘8‘};
- // jstring encoding = env->NewString(encoding_name, 5);
- return (jstring)env->NewObject(strClass, ctorID, bytes, encoding);
- // jbyte buffer[] = /* UTF8 encoding buffer */
- //
- // jbyteArray bytes = env->NewByteArray(sizeof(buffer));
- //
- // env->SetByteArrayRegion(bytes, 0, sizeof(buffer), buffer);
- // return bytes;
- }
- /*
- * Class: com_example_base64test_JniTest
- * Method: decode
- * Signature: (Ljava/lang/String;)Ljava/lang/String;
- */
- JNIEXPORT jstring JNICALL Java_com_example_base64test_JniTest_decode
- (JNIEnv *env, jobject obj, jstring base)
- {
- // 先将jstring转换成char*
- char *t = 0;
- jclass clsstring = env->FindClass("java/lang/String");
- jstring strencode = env->NewStringUTF("utf-8");
- jmethodID mid = env->GetMethodID(clsstring, "getBytes", "(Ljava/lang/String;)[B");
- jbyteArray barr= (jbyteArray)env->CallObjectMethod(base, mid, strencode);
- jsize alen = env->GetArrayLength(barr);
- jbyte* ba = env->GetByteArrayElements(barr, JNI_FALSE);
- if (alen > 0)
- {
- t = (char*)malloc(alen + 1);
- memcpy(t, ba, alen);
- t[alen] = 0;
- }
- env->ReleaseByteArrayElements(barr, ba, 0);
- // 此时的t里面有了jstring的内容
- int i = 0;
- int j = strlen(t);
- // char *enc = base64_encode(t, j);
- // int len = strlen(enc);
- char *dec = base64_decode(t, j);
- LOGD("\noriginal: %s\n", t);
- // LOGD("\nencoded : %s\n", enc);
- LOGD("\ndecoded : %s\n", dec);
- // free(enc);
- free(dec);
- // 将base64编码后的char转换成jstring返回给java层
- // jclass strClass = env->FindClass("Ljava/lang/String;");
- jclass strClass = env->FindClass("java/lang/String");
- jmethodID ctorID = env->GetMethodID(strClass, "<init>", "([BLjava/lang/String;)V");
- jbyteArray bytes = env->NewByteArray(strlen(dec));
- env->SetByteArrayRegion(bytes, 0, strlen(dec), (jbyte*)dec);
- jstring encoding = env->NewStringUTF("utf-8");
- jobject result = env->NewObject(strClass, ctorID, bytes, encoding);
- return (jstring)env->NewObject(strClass, ctorID, bytes, encoding);
- // return result;
- // return bytes;
- }
- /* */
- char *base64_encode(const char* data, int data_len)
- {
- //int data_len = strlen(data);
- int prepare = 0;
- int ret_len;
- int temp = 0;
- char *ret = NULL;
- char *f = NULL;
- int tmp = 0;
- char changed[4];
- int i = 0;
- ret_len = data_len / 3;
- temp = data_len % 3;
- if (temp > 0)
- {
- ret_len += 1;
- }
- ret_len = ret_len*4 + 1;
- ret = (char *)malloc(ret_len);
- if ( ret == NULL)
- {
- LOGD("No enough memory.\n");
- exit(0);
- }
- memset(ret, 0, ret_len);
- f = ret;
- while (tmp < data_len)
- {
- temp = 0;
- prepare = 0;
- memset(changed, ‘\0‘, 4);
- while (temp < 3)
- {
- //printf("tmp = %d\n", tmp);
- if (tmp >= data_len)
- {
- break;
- }
- prepare = ((prepare << 8) | (data[tmp] & 0xFF));
- tmp++;
- temp++;
- }
- prepare = (prepare<<((3-temp)*8));
- //printf("before for : temp = %d, prepare = %d\n", temp, prepare);
- for (i = 0; i < 4 ;i++ )
- {
- if (temp < i)
- {
- changed[i] = 0x40;
- }
- else
- {
- changed[i] = (prepare>>((3-i)*6)) & 0x3F;
- }
- *f = base[changed[i]];
- //printf("%.2X", changed[i]);
- f++;
- }
- }
- *f = ‘\0‘;
- return ret;
- }
- /* */
- static char find_pos(char ch)
- {
- char *ptr = (char*)strrchr(base, ch);//the last position (the only) in base[]
- return (ptr - base);
- }
- /* */
- char *base64_decode(const char *data, int data_len)
- {
- int ret_len = (data_len / 4) * 3;
- int equal_count = 0;
- char *ret = NULL;
- char *f = NULL;
- int tmp = 0;
- int temp = 0;
- char need[3];
- int prepare = 0;
- int i = 0;
- if (*(data + data_len - 1) == ‘=‘)
- {
- equal_count += 1;
- }
- if (*(data + data_len - 2) == ‘=‘)
- {
- equal_count += 1;
- }
- if (*(data + data_len - 3) == ‘=‘)
- {//seems impossible
- equal_count += 1;
- }
- switch (equal_count)
- {
- case 0:
- ret_len += 4;//3 + 1 [1 for NULL]
- break;
- case 1:
- ret_len += 4;//Ceil((6*3)/8)+1
- break;
- case 2:
- ret_len += 3;//Ceil((6*2)/8)+1
- break;
- case 3:
- ret_len += 2;//Ceil((6*1)/8)+1
- break;
- }
- ret = (char *)malloc(ret_len);
- if (ret == NULL)
- {
- LOGD("No enough memory.\n");
- exit(0);
- }
- memset(ret, 0, ret_len);
- f = ret;
- while (tmp < (data_len - equal_count))
- {
- temp = 0;
- prepare = 0;
- memset(need, 0, 4);
- while (temp < 4)
- {
- if (tmp >= (data_len - equal_count))
- {
- break;
- }
- prepare = (prepare << 6) | (find_pos(data[tmp]));
- temp++;
- tmp++;
- }
- prepare = prepare << ((4-temp) * 6);
- for (i=0; i<3 ;i++ )
- {
- if (i == temp)
- {
- break;
- }
- *f = (char)((prepare>>((2-i)*8)) & 0xFF);
- f++;
- }
- }
- *f = ‘\0‘;
- return ret;
- }
不过这个例子里面,log打印的都是正确的,可是返回到java层的确是乱码,这个问题暂时还没有解决。希望有明白的同志告知一下。谢谢。工程附件中。
Base64编解码Android和ios的例子,补充JNI中的例子,布布扣,bubuko.com