我们在使用第三方动态库 时长出现动态库无法读取jar包内的动态库文件，以下代码希望对大家有帮助

• 废话不多说，上代码：
• 此处以大华监控为例

创建名为dynamic-lib-load.xml的文件

<?xml version="1.0" encoding="UTF-8" ?>
<dynamic-lib>
    <win64>
        <lib>avnetsdk</lib>
        <lib>dhconfigsdk</lib>
        <lib>dhnetsdk</lib>
        <lib>dhplay</lib>
        <lib>ImageAlg</lib>
        <lib>Infra</lib>
        <lib>IvsDrawer</lib>
        <lib>StreamConvertor</lib>
        <lib>jninetsdk</lib>
    </win64>
    <win32>
        <lib>avnetsdk</lib>
        <lib>dhconfigsdk</lib>
        <lib>dhnetsdk</lib>
        <lib>dhplay</lib>
        <lib>Infra</lib>
        <lib>ImageAlg</lib>
        <lib>StreamConvertor</lib>
        <lib>jninetsdk</lib>
    </win32>
    <linux64>
        <lib>avnetsdk</lib>
        <lib>dhnetsdk</lib>
        <lib>dhconfigsdk</lib>
        <lib>StreamConvertor</lib>
        <lib>jninetsdk</lib>
    </linux64>
    <linux32>
        <lib>avnetsdk</lib>
        <lib>dhconfigsdk</lib>
        <lib>dhnetsdk</lib>
        <lib>StreamConvertor</lib>
        <lib>jninetsdk</lib>
    </linux32>
    <mac64>
        <lib>avnetsdk</lib>
        <lib>dhnetsdk</lib>
        <lib>dhconfigsdk</lib>
        <lib>StreamConvertor</lib>
    </mac64>
</dynamic-lib>

资源目录结构如下

工具类LibraryLoad

@Slf4j
public class LibraryLoad {
    private static final String ARCH_WINDOWS = "win";
    private static final String ARCH_LINUX = "linux";
    private static final String ARCH_MAC = "mac";
    private static final int PREFIX_64 = 64;
    private static final int PREFIX_32 = 32;
    private static final String PREFIX_ARM = "ARM";
    private static final String EXTERNAL_WIN = ".dll";
    private static final String EXTERNAL_LINUX = ".so";
    private static final String EXTERNAL_MAC = ".dylib";
    private static DynamicParseUtil dynamicParseUtil;
    /**
     * 当前读取的目录
     */
    private static String currentFold;
    /**
     * 动态库需要写入的目录
     */
    private static String EXTRACT_PATH = System.getProperty("java.io.tmpdir");

    private static boolean written = false;

    /**
     * 设置动态库写入的路径,适用于需要自定义加载路径的用户
     *
     * @param path 动态库写入的文件夹,从该文件夹下加载sdk的动态库
     */
    public static void setExtractPath(String path) {
        EXTRACT_PATH = path;
    }

    public static String getExtractPath() {
        return EXTRACT_PATH;

    }

    /**
     * 动态库路径
     */
    private static String INNER_PATH;

    // private static final String EXTERNAL_MAC = ".so";

    private static String extractNetSDKLib(String libName) {
        return extractLibrary(libName);
    }

    public static String getLoadLibrary(String libraryName) {
        currentFold = getLibraryFold();
        if (dynamicParseUtil == null) {
            try {
                dynamicParseUtil =
                        new DynamicParseUtil(
                                LibraryLoad.class.getClassLoader().getResourceAsStream("dynamic-lib-load.xml"));
                if (!written) {
                    for (String libName : dynamicParseUtil.getLibsSystem(currentFold)) {
                        extractLibrary(libName);
                    }
                    written = true;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        String fullName = getLibraryName(libraryName);
        String path = EXTRACT_PATH;
        if (!(EXTRACT_PATH.endsWith("/") || EXTRACT_PATH.endsWith("\\"))) {
            path = EXTRACT_PATH + "/";
        }
        log.info("load library: " + path + fullName);
        return path + fullName;
    }

    /**
     * 将jar包里的动态库写入到系统缓存目录,使用绝对路径加载动态库
     *
     * @param libName
     * @return
     */
    private static String extractLibrary(String libName) {
        return extractLibrary("", libName);
    }

    /**
     * 相对路径文件夹
     *
     * @param relativePath 相对路径
     * @param libName      动态库路径
     * @return
     */
    private static String extractLibrary(String relativePath, String libName) {
        if (libName.trim().equals("")) {
            return "";
        }
        String libFullName = getLibraryName(libName);
        String dir = getLibraryFold();
        if (!(relativePath.endsWith("/") || relativePath.endsWith("\\"))) {
            relativePath = relativePath + "/";
        }
        String fileName = relativePath + "libs/" + dir + "/" + libFullName;
        InputStream in = LibraryLoad.class.getResourceAsStream(fileName);
        BufferedInputStream reader;
        FileOutputStream writer;
        File extractedLibFile = null;
        try {
            if (in == null) {
                in = new FileInputStream(fileName);
                if (in == null) {
                    return "";
                }
            }
            String nativeTempDir = EXTRACT_PATH;
            if (!(nativeTempDir.endsWith("/") || nativeTempDir.endsWith("\\"))) {
                nativeTempDir = nativeTempDir + "/";
            }
            extractedLibFile = new File(nativeTempDir + libFullName);
            reader = new BufferedInputStream(in);
            writer = new FileOutputStream(extractedLibFile);
            byte[] buffer = new byte[1024];
            while (true) {
                int len = reader.read(buffer);
                if (len == 0 || len == -1) break;
                writer.write(buffer, 0, len);
            }
            reader.close();
            writer.close();
            in.close();
        } catch (Exception e) {
            log.error("dynamic file[ "
                    + fileName
                    + " ] not found in project.please ensure you need this library.");
        }
        return extractedLibFile != null ? extractedLibFile.getAbsolutePath() : "";
    }

    /**
     * 获取动态库完整名称
     *
     * @param libName
     * @return
     */
    private static String getLibraryName(String libName) {
        String dir = currentFold;
        String libPrefix = "";
        String libExtension = EXTERNAL_WIN;

        if (!dir.contains("win")) {
            libPrefix = "lib";
            if (dir.contains("linux")) {
                libExtension = EXTERNAL_LINUX;
                log.info("当前为LINUX环境");
            } else {
                // libExtension=".dylib";
                libExtension = EXTERNAL_MAC;
                log.info("当前为MAC环境");
            }
        }
        log.info("当前为win环境");
        libName = dynamicParseUtil.compareLibName(currentFold, libName);
        // 动态库以lib开头，则不添加lib前缀
        // 以lib开头的库则不添加lib前缀
        return (libName.startsWith("lib") ? "" : libPrefix) + libName + libExtension;
    }

    // 获取系统对应的动态库文件夹
    private static String getLibraryFold() {
        String osType;
        String osName = System.getProperty("os.name");
        if (osName.toLowerCase().startsWith("linux")) {
            osType = ARCH_LINUX;
        } else if (osName.toLowerCase().startsWith("mac")
                || osName.toLowerCase().startsWith("darwin")) {
            osType = ARCH_MAC;
        } else if (osName.toLowerCase().startsWith("windows")) {
            osType = ARCH_WINDOWS;
        } else {
            osType = "";
        }
        String arch = System.getProperty("os.arch");
        arch = arch.toLowerCase().trim();
        if ("i386".equals(arch) || "i686".equals(arch) || "x86".equals(arch)) {
            arch = PREFIX_32 + "";
        } else if ("x86_64".equals(arch) || "amd64".equals(arch)) {
            arch = PREFIX_64 + "";
        } else if (arch.startsWith("arm")) {
            arch = PREFIX_ARM + "";
        }
        return osType + arch;
    }
}

DynamicParseUtil工具类

public class DynamicParseUtil {
    private DynamicLibParseHandler handler;
    private SAXParserFactory saxParserFactory;
    private SAXParser saxParser;

    /**
     * 适配各系统动态库名称大小写不同,以及lib前缀造成的找不到库的问题
     *
     * @param currentSystem 当前系统:win64,win32,linux64,linux32,mac64
     * @param libName       动态库名称
     * @return
     */
    public String compareLibName(String currentSystem, String libName) {
        String dynamicLibName = libName;
        List<String> libs = handler.getLibsBySystem(currentSystem);
        if (currentSystem.toLowerCase().contains("win")) {
            return findLibs(libs, libName);
        }
        if (libName.startsWith("lib")) {
            dynamicLibName = libName.substring(3);
        }
        return findLibs(libs, dynamicLibName);
    }

    private String findLibs(List<String> libs, String libName) {
        for (String lib : libs) {
            if (libName.equalsIgnoreCase(lib)) {
                return lib;
            }
        }
        return "";
    }

    public List<String> getLibsSystem(String system) {
        return handler.getLibsBySystem(system);
    }

    private DynamicParseUtil() throws ParserConfigurationException {
        // 获取SAX分析器的工厂实例，专门负责创建SAXParser分析器
        saxParserFactory = SAXParserFactory.newInstance();
        // 获取SAXParser分析器的实例
        try {
            saxParser = saxParserFactory.newSAXParser();
            handler = new DynamicLibParseHandler();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public DynamicParseUtil(InputStream inputSteam)
            throws ParserConfigurationException, IOException, SAXException {
        this();
        saxParser.parse(inputSteam, handler);
    }

    /**
     * xml解析handler
     */
    private class DynamicLibParseHandler extends DefaultHandler {
        private HashMap<String, List<String>> dynamics = new HashMap<String, List<String>>();
        private List<String> systems =
                Arrays.asList("win64", "win32", "linux64", "linux32", "mac64", "linuxARM");
        private String currentDynamicSystem;
        private List<String> libs;

        public List<String> getLibsBySystem(String system) {
            return dynamics.get(system);
        }

        @Override
        public void startDocument() throws SAXException {
            super.startDocument();
        }

        @Override
        public void startElement(String uri, String localName, String qName, Attributes attributes)
                throws SAXException {
            super.startElement(uri, localName, qName, attributes);
            if (systems.contains(qName)) {
                currentDynamicSystem = qName;
                if (libs == null) {
                    libs = new ArrayList<String>();
                }
            }
        }

        @Override
        public void endElement(String uri, String localName, String qName) throws SAXException {
            super.endElement(uri, localName, qName);
            if (systems.contains(qName)) {
                // 保存到hashmap中
                dynamics.put(currentDynamicSystem, libs);
                // 清除libs
                libs = null;
            }
        }

        @Override
        public void characters(char[] ch, int start, int length) throws SAXException {
            super.characters(ch, start, length);
            String lib = new String(ch, start, length);
            if (!lib.trim().isEmpty()) {
                libs.add(lib);
            }
        }
    }
}

调用

public interface NetSDKLib extends Library {

    NetSDKLib NETSDK_INSTANCE = Native.load(LibraryLoad.getLoadLibrary("dhnetsdk"), NetSDKLib.class);
}