java - Java中如何重用没有框架的实例？

Question

我使用browscap-java在我的项目中。但初始加载时间太长。

final UserAgentParser parser = new UserAgentService().loadParser();

加载代码耗时约22058ms。

这是我的代码:

 public String[] getAgentInfo() {
    final UserAgentParser parser;
    try {
        parser = new UserAgentService().loadParser();
    } catch (IOException e) {
        e.printStackTrace();
        return null;
    } catch (ParseException e) {
        e.printStackTrace();
        return null;
    }
    final String userAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36";
    final Capabilities capabilities = parser.parse(userAgent);
    final String[] agentInfo = new String[6];

    agentInfo[0] = capabilities.getBrowser();
    agentInfo[1] = capabilities.getBrowserType();
    agentInfo[2] = capabilities.getBrowserMajorVersion();
    agentInfo[3] = capabilities.getDeviceType();
    agentInfo[4] = capabilities.getPlatform();
    agentInfo[5] = capabilities.getPlatformVersion();

    return agentInfo;
}

每次使用这个函数都会初始化parser 。但是parser是不变的，所以我想知道如何重用parser ，使 parser仅在第一次初始化。

PS:该代码适用于java web。

Answer 1

您可以在此方法之外初始化/构建解析器并将其作为参数传递。这将使您能够灵活地初始化解析器一次并通过传递已初始化的解析器多次调用此方法。

public UserAgentParser createUserAgentParser() {
    final UserAgentParser parser;
    try {
        parser = new UserAgentService().loadParser();
    } catch (IOException e) {
        e.printStackTrace();
        return null;
    } catch (ParseException e) {
        e.printStackTrace();
        return null;
    }
    return parser;
 }

 public String[] getAgentInfo(final UserAgentParser parser) {

    final String userAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36";
    final Capabilities capabilities = parser.parse(userAgent);
    final String[] agentInfo = new String[6];

    agentInfo[0] = capabilities.getBrowser();
    agentInfo[1] = capabilities.getBrowserType();
    agentInfo[2] = capabilities.getBrowserMajorVersion();
    agentInfo[3] = capabilities.getDeviceType();
    agentInfo[4] = capabilities.getPlatform();
    agentInfo[5] = capabilities.getPlatformVersion();

    return agentInfo;
}