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Lack of imagination is one of our worst sins as software developers. We do the same things over and over again, but we rarely modify our ways - me at least. After some years, these are the tools that made it into my tricks box for everyday tasks. Tiresome operations are not my thing.
Chances are you are already using at least some of these, but here we go anyways:
StringUtils
The bread and butter of the commons-lang library, this utility class includes some methods that should seriously have been included in String long time ago.
StringUtils.isEmpty(null) && StringUtils.isEmpty(""); // true
StringUtils.isBlank(" /n/t"); // true
StringUtils.substringAfterLast("foo.bar.baz", "."); // "baz"
StringUtils.substringBeforeLast("foo.bar.baz", "."); // "foo.bar"
StringUtils.split("foo.bar.baz", '.'); // { "foo", "bar", "baz" }
StringUtils.split("foo, bar,baz", ", "); // { "foo", "bar", "baz" }
StringUtils.leftPad("1", 3, '0'); // "001"
IOUtils and FileUtils
A must-have for the rare occasions where you need to manipulate files by hand. Both are pretty much alike (FileUtils for File, IOUtils for InputStream and Reader classes) and come bundled in commons-io.
File file1;
File file2;
InputStream inputStream;
OutputStream outputStream;
// copy one file into another
FileUtils.copyFile(file1, file2);
IOUtils.copy(inputStream, outputStream);
// read a file into a String
String s1 = FileUtils.readFileToString(file1);
String s2 = IOUtils.toString(inputStream);
// read a file into a list of Strings, one item per line
List<String> l1 = FileUtils.readLines(file1);
List<String> l2 = IOUtils.readLines(inputStream);
// put this in your finally() clause after manipulating streams
IOUtils.closeQuietly(inputStream);
// return the list of xml and text files in the specified folder and any subfolders
Collection<File> c1 = FileUtils.listFiles(file1, { "xml", "txt" }, true);
// copy one folder and its contents into another
FileUtils.copyDirectoryToDirectory(file1, file2);
// delete one folder and its contents
FileUtils.deleteDirectory(file1);
Google collections
This is the best implementation of a collections extension that I know of. Some of these are shouting to be included in the JDK:
// create an ArrayList with three arguments
List<String> list = Lists.newArrayList("foo", "bar", "baz");
// notice that there is no generics or class cast,
// and still this line does not generate a warning.
Set<String> s = Sets.newConcurrentHashSet();
// intersect and union are basic features of a Set, if you ask me
Set<String> s = Sets.intersect(s1, s2);
// Example of multiple values in a Map
ListMultimap<String, Validator> validators = new ArrayListMultimap<String, Validator>();
validators.put("save", new RequiredValidator());
validators.put("save", new StringValidator());
validators.put("delete", new NumberValidator());
validators.get("save"); // { RequiredValidator, StringValidator }
validators.get("foo"); // empty List (not null)
validators.values(); // { RequiredValidator, StringValidator, NumberValidator }
java.util.concurrent
Not everybody needs the heavy lifting of java.util.concurrent, but the concurrent collections are handy:
// a map that may be modified (by the same or different thread) while being iterated
Map<String, Something> repository = new ConcurrentHashMap<String, Something>();
// same with lists. This one is only available with Java 6
List<Something> list = new CopyOnWriteArrayList<Something>();
Hardly a large toolbox, is it? If your favourite library is missing, feel free to add it :)
Author：coloma
Profile：I'm a java architect that shares some development time at Extrema Sistemas, where Loom was born - the web framework that sets a new standard for "Kicks Ass".
其中StirngUtils是http://commons.apache.org/ 的lang类库中的一个类，FileUtils和IOUtils时io包中的一个类。
Google collections 在http://code.google.com/p/google-collections/中，读者可以从网站上下载，加入到开发过程中。
下面有一个中文版本：
我的顶级JAVA工具单
作为一个软件开发者，缺乏想象力是最严重的罪过之一。我们经常把事情重复做一遍又一遍，但是我们很少改变这种方式，至少我是这样。经过这些年开发，在我的工具箱里面有了一些每个项目我都需要用到的工具，烦人的重复工作不再是我的事。
下面这些工具也许你已经用到，让我来仔细介绍它们：
StringUitls
这是象面包和奶油一样必须的通用语言库，这个实用工具类包括一些很早以前在String中未包含的重要方法。
Java代码
1. StringUtils.isEmpty(null) && StringUtils.isEmpty(""); // true
2. StringUtils.isBlank(" /n/t"); // true
3. StringUtils.substringAfterLast("foo.bar.baz", "."); // "baz"
4. StringUtils.substringBeforeLast("foo.bar.baz", "."); // "foo.bar"
5. StringUtils.split("foo.bar.baz", '.'); // { "foo", "bar", "baz" }
6. StringUtils.split("foo, bar,baz", ", "); // { "foo", "bar", "baz" }
7. StringUtils.leftPad("1", 3, '0'); // "001"
StringUtils.isEmpty(null) && StringUtils.isEmpty(""); // true
StringUtils.isBlank(" /n/t"); // true
StringUtils.substringAfterLast("foo.bar.baz", "."); // "baz"
StringUtils.substringBeforeLast("foo.bar.baz", "."); // "foo.bar"
StringUtils.split("foo.bar.baz", '.'); // { "foo", "bar", "baz" }
StringUtils.split("foo, bar,baz", ", "); // { "foo", "bar", "baz" }
StringUtils.leftPad("1", 3, '0'); // "001"
IOUtils and FileUtils
在一种当你需要手动操作多个文件罕见情况下必须具备的工具，这两个工具很相似(FileUtils操作文件，IOUtils操作InputStream和Reader classes)，和捆绑常用IO.
Java代码
1. File file1;
2. File file2;
3. InputStream inputStream;
4. OutputStream outputStream;
5.
6. // copy one file into another
7. FileUtils.copyFile(file1, file2);
8. IOUtils.copy(inputStream, outputStream);
9.
10. // read a file into a String
11. String s1 = FileUtils.readFileToString(file1);
12. String s2 = IOUtils.toString(inputStream);
13.
14. // read a file into a list of Strings, one item per line
15. List<String> l1 = FileUtils.readLines(file1);
16. List<String> l2 = IOUtils.readLines(inputStream);
17.
18. // put this in your finally() clause after manipulating streams
19. IOUtils.closeQuietly(inputStream);
20.
21. // return the list of xml and text files in the specified folder and any subfolders
22. Collection<File> c1 = FileUtils.listFiles(file1, { "xml", "txt" }, true);
23.
24. // copy one folder and its contents into another
25. FileUtils.copyDirectoryToDirectory(file1, file2);
26.
27. // delete one folder and its contents
28. FileUtils.deleteDirectory(file1);
File file1;
File file2;
InputStream inputStream;
OutputStream outputStream;
// copy one file into another
FileUtils.copyFile(file1, file2);
IOUtils.copy(inputStream, outputStream);
// read a file into a String
String s1 = FileUtils.readFileToString(file1);
String s2 = IOUtils.toString(inputStream);
// read a file into a list of Strings, one item per line
List<String> l1 = FileUtils.readLines(file1);
List<String> l2 = IOUtils.readLines(inputStream);
// put this in your finally() clause after manipulating streams
IOUtils.closeQuietly(inputStream);
// return the list of xml and text files in the specified folder and any subfolders
Collection<File> c1 = FileUtils.listFiles(file1, { "xml", "txt" }, true);
// copy one folder and its contents into another
FileUtils.copyDirectoryToDirectory(file1, file2);
// delete one folder and its contents
FileUtils.deleteDirectory(file1);
Google collections
这是我所知道的最好的扩展实现包，其中一些被社区叫嚣着要加入JDK：
Java代码
1. // create an ArrayList with three arguments
2. List<String> list = Lists.newArrayList("foo", "bar", "baz");
3.
4. // notice that there is no generics or class cast,
5. // and still this line does not generate a warning.
6. Set<String> s = Sets.newConcurrentHashSet();
7.
8. // intersect and union are basic features of a Set, if you ask me
9. Set<String> s = Sets.intersect(s1, s2);
10.
11. // Example of multiple values in a Map
12. ListMultimap<String, Validator> validators = new ArrayListMultimap<String, Validator>();
13. validators.put("save", new RequiredValidator());
14. validators.put("save", new StringValidator());
15. validators.put("delete", new NumberValidator());
16.
17. validators.get("save"); // { RequiredValidator, StringValidator }
18. validators.get("foo"); // empty List (not null)
19. validators.values(); // { RequiredValidator, StringValidator, NumberValidator }
// create an ArrayList with three arguments
List<String> list = Lists.newArrayList("foo", "bar", "baz");
// notice that there is no generics or class cast,
// and still this line does not generate a warning.
Set<String> s = Sets.newConcurrentHashSet();
// intersect and union are basic features of a Set, if you ask me
Set<String> s = Sets.intersect(s1, s2);
// Example of multiple values in a Map
ListMultimap<String, Validator> validators = new ArrayListMultimap<String, Validator>();
validators.put("save", new RequiredValidator());
validators.put("save", new StringValidator());
validators.put("delete", new NumberValidator());
validators.get("save"); // { RequiredValidator, StringValidator }
validators.get("foo"); // empty List (not null)
validators.values(); // { RequiredValidator, StringValidator, NumberValidator }
java.util.concurrent
不是每个人都需要这么重的java.util.concurrent，但是很好用:
Java代码
1. // a map that may be modified (by the same or different thread) while being iterated
2. Map<String, Something> repository = new ConcurrentHashMap<String, Something>();
3.
4. // same with lists. This one is only available with Java 6
5. List<Something> list = new CopyOnWriteArrayList<Something>();
// a map that may be modified (by the same or different thread) while being iterated
Map<String, Something> repository = new ConcurrentHashMap<String, Something>();
// same with lists. This one is only available with Java 6
List<Something> list = new CopyOnWriteArrayList<Something>();
你有好的工具推荐吗？欢迎留言。本文章为转载内容，我们尊重原作者对文章享有的著作权。如有内容错误或侵权问题，欢迎原作者联系我们进行内容更正或删除文章。
