java.io.FileNotFoundException :(系统找不到指定的路径）jar结果

Question

您好我在Java中有这个jar问题。我设置的路径无法识别。我在jar里面查了一下，发现路径是正确的，我已经删除并在Java文件和路径的开头添加了“/”，但仍然不起作用。还有什么我可以尝试吗？

CODE

package sample; 


public class LocateMyCity { 

    private String myCityLocation; 

    private String country; 

    public String getCountry() { 
     return country; 
    } 

public String getmyCityLocation(){ 
    return myCityLocation; 
} 

public LocateMyCity() { 
    // A File object pointing to your GeoIP2 or GeoLite2 database 
    File database = new File("\\GeoLite2-City_20170502\\GeoLite2-City.mmdb"); 

    try { 
     URL whatismyip = new URL("http://checkip.amazonaws.com"); 
     BufferedReader in = new BufferedReader(new InputStreamReader(
       whatismyip.openStream())); 

     String ip = in.readLine(); //you get the IP as a String 
     System.out.println(ip); 

     // This creates the DatabaseReader object, which should be reused across 
     // lookups. 
     DatabaseReader reader = new DatabaseReader.Builder(database).build(); 

     InetAddress ipAddress = InetAddress.getByName(ip); 

     // Replace "city" with the appropriate method for your database, e.g., 
     // "country". 
     CityResponse response = reader.city(ipAddress); 

     City city = response.getCity(); 
     System.out.println(city.getName()); // 'Minneapolis' 
     this.myCityLocation = city.getName(); 

     Country country = response.getCountry(); 
     System.out.println(country.getIsoCode());   // 'GB' 
     this.country = country.getIsoCode(); 

     System.out.println(country.getName());    // 'United Kindom' 

    }catch (Exception e){ 
     e.printStackTrace(); 
     System.out.println("Tracing IP E"); 
    } 
} 

}从命令提示

错误消息

java.io.FileNotFoundException: \GeoLite2-City_20170502\GeoLite2-City.mmdb (The system cannot find the path specified) 
    at java.io.RandomAccessFile.open0(Native Method) 
    at java.io.RandomAccessFile.open(Unknown Source) 
    at java.io.RandomAccessFile.<init>(Unknown Source) 
    at com.maxmind.db.BufferHolder.<init>(BufferHolder.java:19) 
    at com.maxmind.db.Reader.<init>(Reader.java:116) 
    at com.maxmind.geoip2.DatabaseReader.<init>(DatabaseReader.java:35) 
    at com.maxmind.geoip2.DatabaseReader.<init>(DatabaseReader.java:23) 
    at com.maxmind.geoip2.DatabaseReader$Builder.build(DatabaseReader.java:129) 
    at sample.LocateMyCity.<init>(LocateMyCity.java:44) 
    at sample.WeatherToday.getPersonLocationId(WeatherToday.java:102) 
    at sample.WeatherToday.<init>(WeatherToday.java:126) 
    at sample.Main.start(Main.java:37) 
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863) 
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326) 
    at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294) 
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95) 
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method) 
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191) 
    at java.lang.Thread.run(Unknown Source) 

Answer 1

替换

File database = new File("\\GeoLite2-City_20170502\\GeoLite2-City.mmdb"); 

与

File file = new File(classLoader.getResource("\\GeoLite2-City_20170502\\GeoLite2-City.mmdb").getFile()); 

Answer 2

您指定的路径是相对的，也许出发点是不是你有你要找的文件。尝试这样的事情

ClassLoader classLoader = getClass().getClassLoader(); 
File file = new File(classLoader.getResource("GeoLite2-City_20170502/GeoLite2-City.mmdb").getFile()); 

并把该目录在你的JAR的起点（如果使用Maven在src /资源/）