使用MaxMind java类与ColdFusion [英] Using MaxMind java class with ColdFusion

问题描述

我试图使用ColdFusion的MaxMind java库。

I'm trying to use MaxMind java library with ColdFusion.

我开始在官方的MaxMind网站上转换这个示例代码：

I start converting this sample code on official MaxMind site:

// A File object pointing to your GeoIP2 or GeoLite2 database
File database = new File("/path/to/GeoIP2-City.mmdb");

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

InetAddress ipAddress = InetAddress.getByName("128.101.101.101");

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

Country country = response.getCountry();

我试过的是：

var file = "pathto\maxmind\GeoLite2-City.mmdb";
var db = createObject("java","java.io.File").init(file);

var mm = createObject("java", "com.maxmind.geoip2.DatabaseReader")
.Builder(db)
.build();

dump(c);abort;

我遇到此错误：

Type: java.lang.NoSuchMethodException 
Messages: No matching Method for Builder(java.io.File) found 
for com.maxmind.geoip2.DatabaseReader

我做错了什么？

推荐答案

（更新： @oschwald已提供答案，但是，我将此留作扩展注释，因为它包含一些有关从CF访问内部类和构造函数的有用细节）。

(Update: @oschwald already provided the answer. However, I am leaving this as an extended comment as it contains some helpful details about accessing inner classes and constructors from CF)

DatabaseReader reader = new DatabaseReader.Builder（database）.build（）;

c $ c>。在新类名声明中？这表明Builder是一种特殊类型的类。它是DatabaseReader的嵌套或内部类，因此您需要使用特殊语法来创建它的实例，即 createObject（java，path.OuterClass $ InnerClass）。

Notice the . in the new class name statement? That indicates Builder is a special type of class. It is a nested or inner class of DatabaseReader, so you need to use a special syntax to create an instance of it, ie createObject("java", "path.OuterClass$InnerClass").

此外，新的DatabaseReader.Builder（数据库）调用Builder类的构造函数来创建一个新的实例。 CF不支持带java对象的new关键字。而应使用 psuedo方法 init（） 调用构造函数：

Also, new DatabaseReader.Builder(database) calls a constructor of the Builder class to create a new instance. CF does not support the "new" keyword with java objects. Instead, use the psuedo method init() to call the constructor:

var mm = createObject("java", "com.maxmind.geoip2.DatabaseReader$Builder").init(db).build();

注意：调用 init code>仅当调用类构造函数与一个或多个参数，如这里的情况。如果java代码改为使用默认的无参构造函数 new DatabaseReader.Builder（）。build（），你可以在技术上省略对 init（）。如果需要，当调用第一个非静态方法（即 build（））时，CF自动调用无参构造函数。

NB: Calling init() explicitly is only required when invoking a class constructor with one or more arguments, as is the case here. If the java code was instead using the default, no-argument constructor ie new DatabaseReader.Builder().build(), you could technically omit the call to init(). CF automatically invokes the no-argument constructor if needed, when the first non-static method - ie build() - is invoked.

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