谈话有点晚了,但我偶然发现了谷歌的这个答案…
有一个纯JDK实现
here
在matchingsubset()函数中,通过迭代propertyname()返回的属性来查找匹配项。如果您真的需要使用regex,它可以很容易地进行调整。
如果链接出错,请在下面发布代码段:
/**
* Copyright 2007 University Of Southern California
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
public Properties matchingSubset(String prefix, boolean keepPrefix) {
Properties result = new Properties();
// sanity check
if (prefix == null || prefix.length() == 0) {
return result;
}
String prefixMatch; // match prefix strings with this
String prefixSelf; // match self with this
if (prefix.charAt(prefix.length() - 1) != '.') {
// prefix does not end in a dot
prefixSelf = prefix;
prefixMatch = prefix + '.';
} else {
// prefix does end in one dot, remove for exact matches
prefixSelf = prefix.substring(0, prefix.length() - 1);
prefixMatch = prefix;
}
// POSTCONDITION: prefixMatch and prefixSelf are initialized!
// now add all matches into the resulting properties.
// Remark 1: #propertyNames() will contain the System properties!
// Remark 2: We need to give priority to System properties. This is done
// automatically by calling this class's getProperty method.
String key;
for (Enumeration e = propertyNames(); e.hasMoreElements(); ) {
key = (String) e.nextElement();
if (keepPrefix) {
// keep full prefix in result, also copy direct matches
if (key.startsWith(prefixMatch) || key.equals(prefixSelf)) {
result.setProperty(key,
getProperty(key));
}
} else {
// remove full prefix in result, dont copy direct matches
if (key.startsWith(prefixMatch)) {
result.setProperty(key.substring(prefixMatch.length()),
getProperty(key));
}
}
}
// done
return result;
}