使用groovy更新xml文件时保留格式 [英] preserve formatting when updating xml file with groovy
问题描述
我有大量包含网址的XML文件。我正在编写一个groovy实用程序来查找每个URL并将其替换为更新后的版本。
给定example.xml：
<？xml version =1.0encoding =UTF-8？>
< page>
< content>
<节>
< link>
< url> / some / old / url< / url>
< / link>
< link>
< url> / some / old / url< / url>
< / link>
< / section>
<节>
< link>
< url>
/ a / different / old / url？with = specialChars& amp; amp; amp; amp; amp; ampped; escaped = true
< / url>
< / link>
< / section>
< / content>
< / page>
脚本运行后，example.xml应该包含：
<？xml version =1.0encoding =UTF-8？>
< page>
< content>
<节>
< link>
< url> / a / new / and / improved / url< / url>
< / link>
< link>
< url> / a / new / and / improved / url< / url>
< / link>
< / section>
<节>
< link>
< url>
/ a / different / new /和/ improved / url？with = specialChars& amp; ampEs& amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp;
< / link>
< / section>
< / content>
< / page>
使用groovy优秀的xml支持很容易，除了我想更改URL和其他文件
。我的意思是：
到目前为止，在尝试XmlParser，DOMBuilder，XmlNodePrinter，XmlUtil.serialize（）等多种组合后，我已阅读每个文件一行一行，并应用xml实用程序和正则表达式的混合。
读取和写入每个文件：
files.each {档案档案 - >
def lineEnding = file.text.contains（'\r\\\
'）？ '\r\\\
'：'\\\
'
def newLineAtEof = file.text.endsWith（lineEnding）
def lines = file.readLines（）
file.withWriter {w - >
lines.eachWithIndex {line，index - >
line = update（line）
w.write（line）
if（index< lines.size-1）w.write（lineEnding）
else if（newLineAtEof） w.write（lineEnding）
}
}
}
搜索并更新一行中的网址：
def matcher =（line =〜urlTagRegexp）//匹配< url>元素及其内容
matcher.each {groups - >
def urlNode = new XmlParser（）。parseText（line）
def url = urlNode.text（）
def newUrl = translate（url）
if（newUrl）{
urlNode.value = newUrl
def replacement = nodeToString（urlNode）
line = matcher.replaceAll（替换）
}
}
def nodeToString （节点）{
def writer = new StringWriter（）
writer.withPrintWriter {printWriter - >
def printer = new XmlNodePrinter（printWriter）
printer.preserveWhitespace = true
printer.print（node）
}
writer.toString（）。replaceAll（/ \r\\\
] /，''）
}
除非它不能处理一个标签分割成多行，并且在将文件写回去时搞乱换行是麻烦的。
我是groovy的新手，但我感觉像是必须有一个更加方便的方法来做到这一点。
//gist.github.com/akhikhl/8070808rel =noreferrer> https://gist.github.com/akhikhl/8070808 来演示如何使用Groovy和JDOM2完成这种转换。重要注意事项：
- Groovy技术上允许使用任何java库。如果使用Groovy JDK无法完成
操作，可以使用其他库完成。 应该明确包含 - jaxen库（实现XPath）（通过@Grab或通过maven / gradle），因为它是JDOM2的一个可选依赖项。
- @GrabExclude指令的顺序修复了jaxen对JDOM-1.0的离奇依赖。
- XPathFactory.compile还支持变量绑定和过滤器（请参阅联机javadoc）。
- XPathExpression（由编译器返回）支持两个主要函数 - evaluate和evaluateFirst。评估总是返回所有XML节点的列表，满足指定的谓词，而evaluateFirst只返回第一个匹配的XML节点。
更新
以下代码：
新的XMLOutputter（）。带有{
format = Format.getRawFormat（）
format.setLineSeparator（LineSeparator.NONE）
output（doc，System.out）
}
解决了保留空格和行分隔符的问题。 getRawFormat构造一个保留空格的格式对象。 LineSeparator.NONE指示格式对象，它不应该转换行分隔符。
上面提到的要点也包含这个新代码。
I have a large number of XML files that contain URLs. I'm writing a groovy utility to find each URL and replace it with an updated version.
Given example.xml:
<?xml version="1.0" encoding="UTF-8"?>
<page>
<content>
<section>
<link>
<url>/some/old/url</url>
</link>
<link>
<url>/some/old/url</url>
</link>
</section>
<section>
<link>
<url>
/a/different/old/url?with=specialChars&escaped=true
</url>
</link>
</section>
</content>
</page>
Once the script has run, example.xml should contain:
<?xml version="1.0" encoding="UTF-8"?>
<page>
<content>
<section>
<link>
<url>/a/new/and/improved/url</url>
</link>
<link>
<url>/a/new/and/improved/url</url>
</link>
</section>
<section>
<link>
<url>
/a/different/new/and/improved/url?with=specialChars&stillEscaped=true
</url>
</link>
</section>
</content>
</page>
This is easy to do using groovy's excellent xml support, except that I want to change the URLs and nothing else about the file.
By that I mean:
- whitespace must not change (files might contain spaces, tabs, or both)
- comments must be preserved
- windows vs. unix-style line separators must be preserved
- the xml declaration at the top must not be added or removed
- attributes in tags must retain their order
So far, after trying many combinations of XmlParser, DOMBuilder, XmlNodePrinter, XmlUtil.serialize(), and so on, I've landed on reading each file line-by-line and applying an ugly hybrid of the xml utilities and regular expressions.
Reading and writing each file:
files.each { File file ->
def lineEnding = file.text.contains('\r\n') ? '\r\n' : '\n'
def newLineAtEof = file.text.endsWith(lineEnding)
def lines = file.readLines()
file.withWriter { w ->
lines.eachWithIndex { line, index ->
line = update(line)
w.write(line)
if (index < lines.size-1) w.write(lineEnding)
else if (newLineAtEof) w.write(lineEnding)
}
}
}
Searching for and updating URLs within a line:
def matcher = (line =~ urlTagRegexp) //matches a <url> element and its contents
matcher.each { groups ->
def urlNode = new XmlParser().parseText(line)
def url = urlNode.text()
def newUrl = translate(url)
if (newUrl) {
urlNode.value = newUrl
def replacement = nodeToString(urlNode)
line = matcher.replaceAll(replacement)
}
}
def nodeToString(node) {
def writer = new StringWriter()
writer.withPrintWriter { printWriter ->
def printer = new XmlNodePrinter(printWriter)
printer.preserveWhitespace = true
printer.print(node)
}
writer.toString().replaceAll(/[\r\n]/, '')
}
This mostly works, except it can't handle a tag split over multiple lines, and messing with newlines when writing the files back out is cumbersome.
I'm new to groovy, but I feel like there must be a groovier way of doing this.
I just created gist at: https://gist.github.com/akhikhl/8070808 to demonstrate how such transformation is done with Groovy and JDOM2.
Important notes:
- Groovy technically allows using any java libraries. If something cannot be done with Groovy JDK, it can be done with other library.
- jaxen library (implementing XPath) should be included explicitly (via @Grab or via maven/gradle), since it's an optional dependency of JDOM2.
- The sequence of @Grab/@GrabExclude instructions fixes the quirky dependence of jaxen on JDOM-1.0.
- XPathFactory.compile also supports variable binding and filters (see online javadoc).
- XPathExpression (which is returned by compile) supports two major functions - evaluate and evaluateFirst. evaluate always returns a list of all XML-nodes, satisfying the specified predicate, while evaluateFirst returns just the first matching XML-node.
Update
The following code:
new XMLOutputter().with {
format = Format.getRawFormat()
format.setLineSeparator(LineSeparator.NONE)
output(doc, System.out)
}
solves a problem with preserving whitespaces and line separators. getRawFormat constructs a format object that preserves whitespaces. LineSeparator.NONE instructs format object, that it should not convert line separators.
The gist mentioned above contains this new code as well.
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