android开发-c++代码调用so库

Android项目的CMakeLists.txt代码如下，so文件放在项目的$Project/app/src/main/jniLibs/$arch下，
$arch替换为arm64-v8a armv7a等

cmake_minimum_required(VERSION 3.4.1)
set(ARCH arch-arm64)
set(libs_DIR /Users/musictom/libs/android/${ARCH}/usr/lib)
set(libs_include_DIR /Users/musictom/libs/android/${ARCH}/usr/include)

add_library(ghttp-lib SHARED IMPORTED)
set_target_properties(ghttp-lib PROPERTIES IMPORTED_LOCATION
             ${libs_DIR}/libghttp.so)

add_library( # Sets the name of the library.
native-lib
# Sets the library as a shared library.
SHARED
# Provides a relative path to your source file(s).
src/main/cpp/native-lib.cpp )

target_link_libraries( # Specifies the target library.
native-lib my-lib ghttp-lib pocofoundation-lib poconet-lib pocoutil-lib

# Links the target library to the log library
# included in the NDK.
${log-lib} )

app.gradle如下：

apply plugin: 'com.android.application'

android {
compileSdkVersion 25
buildToolsVersion "25.0.2"
defaultConfig {
applicationId "com.example.musictom.andcpp"
minSdkVersion 21
targetSdkVersion 25
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
externalNativeBuild {
cmake {
cppFlags "-std=c++11 -frtti -fexceptions -I/Users/musictom/libs/android/arch-arm64/usr/include/"
}
}
ndk {
// Specifies the ABI configurations of your native
// libraries Gradle should build and package with your APK.
//'x86', 'x86_64',
abiFilters 'arm64-v8a'
}
// 设置so文件路径 so文件如果不在jniLibs目录下，需要在这里指定目录
//sourceSets {
//    main {
//        jniLibs.srcDirs = ['src/main/jni/arm64-v8a']
//    }
//}
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
externalNativeBuild {
cmake {
path "CMakeLists.txt"
}
}
}

dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support.constraint:constraint-layout:1.0.0-alpha7'
testCompile 'junit:junit:4.12'
}

native-lib.cpp代码如下：

#include <jni.h>
#include <string>

#include <ghttp/ghttp.h>

#include <Poco/Net/HTTPClientSession.h>
#include <Poco/Net/HttpRequest.h>
#include <Poco/Net/HttpResponse.h>
#include <Poco/StreamCopier.h>
#include <Poco/Net/HTMLForm.h>
#include <Poco/Net/NetException.h>
#include <Poco/BinaryReader.h>
#include <Poco/URI.h>
#include <string>

std::string get_ghttp() {
/* This is the http request object */
ghttp_request *request = NULL;
/* Allocate a new empty request object */
request = ghttp_request_new();
/* Set the URI for the request object */
ghttp_set_uri(request, "http://www.fuhan.org/wechat/verify");
/* Close the connection after you are done. */
ghttp_set_header(request, http_hdr_Connection, "close");
/* Prepare the connection */
ghttp_prepare(request);
/* Process the request */
ghttp_process(request);
/* Write out the body. Note that the body of the request may not be null terminated so we have to be careful of the length. */
//fwrite(ghttp_get_body(request), ghttp_get_body_len(request), 1, stdout);
char* buf = ghttp_get_body(request);
std::string s = buf;
/* Destroy the request. This closes any file descriptors that may be open and will free any memory associated with the request. */
ghttp_request_destroy(request);
return s;
}

extern std::string aa();
extern "C"
JNIEXPORT jstring JNICALL
Java_com_example_musictom_andcpp_MainActivity_stringFromJNI(
JNIEnv* env,
jobject /* this */) {
std::string hello = "Hello from C++";
hello = aa();
std::string result;
std::string responseText;

if (false) {

try {
Poco::URI url("http://www.fuhan.org");
Poco::Net::HTTPClientSession session(url.getHost(), url.getPort());
//Poco::Net::HTTPClientSession s("www.cnblogs.com");

//Poco::Net::HTTPRequest request(Poco::Net::HTTPRequest::HTTP_GET, "/auroratony/archive/2012/06/06/2537516.html");
Poco::Net::HTTPRequest request(Poco::Net::HTTPRequest::HTTP_GET, "/wechat/verify",
Poco::Net::HTTPRequest::HTTP_1_1);
//request.set("/wechat/verify", "");

//Poco::Net::HTMLForm form;
//form.add("entry1", "value1");
//form.prepareSubmit(request);
session.sendRequest(request);
Poco::Net::HTTPResponse response;

std::istream &rs = session.receiveResponse(response);

//Poco::StreamCopier copier;
//copier.copyToString(rs, responseText);
std::istreambuf_iterator<char> eos;
            std::string s(std::istreambuf_iterator<char>(rs), eos);
responseText = s;
}
catch (Poco::Net::NetException &ex) {
result = ex.displayText();
responseText = "error:" + result;
}
}
else {
responseText = get_ghttp();
}

return env->NewStringUTF(responseText.c_str());
}