blocks|key|1491903|text|完整示例：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1491904|private+static+final+Pattern+p+=+Pattern.compile("%5E([a-zA-Z]%2B)([0-9]%2B)(.*)");
public+static+void+main(String[]+args)+{
++++//+create+matcher+for+pattern+p+and+given+string
++++Matcher+m+=+p.matcher("Testing123Testing");

++++//+if+an+occurrence+if+a+pattern+was+found+in+a+given+string...
++++if+(m.find())+{
++++++++//+...then+you+can+use+group()+methods.
++++++++System.out.println(m.group(0));+//+whole+matched+expression
++++++++System.out.println(m.group(1));+//+first+expression+from+round+brackets+(Testing)
++++++++System.out.println(m.group(2));+//+second+one+(123)
++++++++System.out.println(m.group(3));+//+third+one+(Testing)
++++}
}|code-block|syntax|javascript|1491905|由于您正在寻找第一个数字，因此可以使用下面的regexp：|1491906|%5E\D%2B(\d%2B).*|1491907|m.group(1)会给你返回第一个数字。请注意，有符号数字可以包含减号：|offset|length|style|CODE|1491908|%5E\D%2B(-?\d%2B).*|1491909|entityMap^0|0|0|0|0|0|A|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|Y|8|@$M|Z|N|10|O|P]]|9|@]|A|$]]|$1|Q|3|R|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

Full example:

<pre><code>private static final Pattern p = Pattern.compile("^([a-zA-Z]+)([0-9]+)(.*)");
public static void main(String[] args) {
 // create matcher for pattern p and given string
 Matcher m = p.matcher("Testing123Testing");

 // if an occurrence if a pattern was found in a given string...
 if (m.find()) {
 // ...then you can use group() methods.
 System.out.println(m.group(0)); // whole matched expression
 System.out.println(m.group(1)); // first expression from round brackets (Testing)
 System.out.println(m.group(2)); // second one (123)
 System.out.println(m.group(3)); // third one (Testing)
 }
}
</code></pre>

Since you're looking for the first number, you can use such regexp:

<pre><code>^\D+(\d+).*
</code></pre>

and <code>m.group(1)</code> will return you the first number. Note that signed numbers can contain a minus sign:

<pre><code>^\D+(-?\d+).*
</code></pre>

blocks|key|1707001|text|在Java+1.4及更高版本中：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1707002|String+input+=+"...";
Matcher+matcher+=+Pattern.compile("[%5E0-9]%2B([0-9]%2B)[%5E0-9]%2B").matcher(input);
if+(matcher.find())+{
++++String+someNumberStr+=+matcher.group(1);
++++//+if+you+need+this+to+be+an+int:
++++int+someNumberInt+=+Integer.parseInt(someNumberStr);
}|code-block|syntax|javascript|1707003|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

In Java 1.4 and up:

<pre><code>String input = "...";
Matcher matcher = Pattern.compile("[^0-9]+([0-9]+)[^0-9]+").matcher(input);
if (matcher.find()) {
 String someNumberStr = matcher.group(1);
 // if you need this to be an int:
 int someNumberInt = Integer.parseInt(someNumberStr);
}
</code></pre>

blocks|key|1707041|text|[%5E\\d]*([0-9]%2B[\\s]*[.,]{0,1}[\\s]*[0-9]*).*怎么样?我想它可以处理小数部分的数字。我包含了空格和,作为可能的分隔符。我试图从一个字符串中提取数字，包括浮点数，并考虑到用户在键入数字时可能会出错并包含空格。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1707042|entityMap^0|0|18|1Y|1|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

How about <code>[^\\d]*([0-9]+[\\s]*[.,]{0,1}[\\s]*[0-9]*).*</code> I think it would take care of numbers with fractional part. 
I included white spaces and included <code>,</code> as possible separator.
I'm trying to get the numbers out of a string including floats and taking into account that the user might make a mistake and include white spaces while typing the number.

blocks|key|1707081|text|试着这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1707082|Pattern+p+=+Pattern.compile("%5E.%2B(\\d%2B).%2B");
Matcher+m+=+p.matcher("Testing123Testing");

if+(m.find())+{
++++System.out.println(m.group(1));
}|code-block|syntax|javascript|1707083|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try doing something like this:

<pre><code>Pattern p = Pattern.compile("^.+(\\d+).+");
Matcher m = p.matcher("Testing123Testing");

if (m.find()) {
 System.out.println(m.group(1));
}
</code></pre>

blocks|key|1707102|text|import+java.util.regex.Matcher;
import+java.util.regex.Pattern;

public+class+Regex1+{
++++public+static+void+main(String[]args)+{
++++++++Pattern+p+=+Pattern.compile("\\d%2B");
++++++++Matcher+m+=+p.matcher("hello1234goodboy789very2345");
++++++++while(m.find())+{
++++++++++++System.out.println(m.group());
++++++++}
++++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1707103|输出：|unstyled|1707104|1234
789
2345|1707105|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Regex1 {
 public static void main(String[]args) {
 Pattern p = Pattern.compile("\\d+");
 Matcher m = p.matcher("hello1234goodboy789very2345");
 while(m.find()) {
 System.out.println(m.group());
 }
 }
}
</code></pre>

Output:

<pre><code>1234
789
2345
</code></pre>

blocks|key|1707139|text|除了Pattern之外，Java+String类还有几个可以处理正则表达式的方法，在您的例子中，代码如下：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1707140|"ab123abc".replaceFirst("\\D*(\\d*).*",+"$1")|code-block|syntax|javascript|1707141|其中\\D是非数字字符。|style|CODE|1707142|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html|1|http://docs.oracle.com/javase/7/docs/api/java/lang/String.html#split%2528java.lang.String,%2520int%2529^0|2|7|0|H|6|1|0|0|2|3|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]|$A|10|B|11|1|12]]|C|$]]|$1|D|3|E|5|F|7|13|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|14|8|@$A|15|B|16|K|L]]|9|@]|C|$]]|$1|M|3|-4|5|6|7|17|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]|U|$5|P|Q|R|C|$S|V]]]]

In addition to <a href="http://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html" rel="noreferrer">Pattern</a>, the Java <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/String.html#split%28java.lang.String,%20int%29" rel="noreferrer">String</a> class also has several methods that can work with regular expressions, in your case the code will be:

<pre><code>"ab123abc".replaceFirst("\\D*(\\d*).*", "$1")
</code></pre>

where <code>\\D</code> is a non-digit character.

blocks|key|1492238|text|听着，你可以用StringTokenizer来实现|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1492239|String+str+=+"as:"%2B123%2B"as:"%2B234%2B"as:"%2B345;
StringTokenizer+st+=+new+StringTokenizer(str,"as:");

while(st.hasMoreTokens())
{
++String+k+=+st.nextToken();++++//+you+will+get+first+numeric+data+i.e+123
++int+kk+=+Integer.parseInt(k);
++System.out.println("k+string+token+in+integer++++++++"+%2B+kk);

++String+k1+=+st.nextToken();+++//++you+will+get+second+numeric+data+i.e+234
++int+kk1+=+Integer.parseInt(k1);
++System.out.println("new+string+k1+token+in+integer+++:"+%2B+kk1);

++String+k2+=+st.nextToken();+++//++you+will+get+third+numeric+data+i.e+345
++int+kk2+=+Integer.parseInt(k2);
++System.out.println("k2+string+token+is+in+integer+++:+"+%2B+kk2);
}|code-block|syntax|javascript|1492240|因为我们将这些数字数据放入三个不同的变量中，所以我们可以在代码中的任何地方使用这些数据(以供进一步使用)|1492241|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Look you can do it using StringTokenizer


<pre><code>String str = "as:"+123+"as:"+234+"as:"+345;
StringTokenizer st = new StringTokenizer(str,"as:");

while(st.hasMoreTokens())
{
 String k = st.nextToken(); // you will get first numeric data i.e 123
 int kk = Integer.parseInt(k);
 System.out.println("k string token in integer " + kk);

 String k1 = st.nextToken(); // you will get second numeric data i.e 234
 int kk1 = Integer.parseInt(k1);
 System.out.println("new string k1 token in integer :" + kk1);

 String k2 = st.nextToken(); // you will get third numeric data i.e 345
 int kk2 = Integer.parseInt(k2);
 System.out.println("k2 string token is in integer : " + kk2);
}
</code></pre>

Since we are taking these numeric data into three different variables we can use this data anywhere in the code (for further use)

blocks|key|1492291|text|此函数从字符串中收集所有匹配的序列。在本例中，它从字符串中获取所有电子邮件地址。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1492292|static+final+String+EMAIL_PATTERN+=+"[_A-Za-z0-9-\\%2B]%2B(\\.[_A-Za-z0-9-]%2B)*@"
++++++++%2B+"[A-Za-z0-9-]%2B(\\.[A-Za-z0-9]%2B)*(\\.[A-Za-z]{2,})";

public+List<String>+getAllEmails(String+message)+{++++++
++++List<String>+result+=+null;
++++Matcher+matcher+=+Pattern.compile(EMAIL_PATTERN).matcher(message);

++++if+(matcher.find())+{
++++++++result+=+new+ArrayList<String>();
++++++++result.add(matcher.group());

++++++++while+(matcher.find())+{
++++++++++++result.add(matcher.group());
++++++++}
++++}

++++return+result;
}|code-block|syntax|javascript|1492293|对于message+=+"adf@gmail.com,+<another@osiem.osiem>>>>+lalala@aaa.pl"，它将创建包含3个元素的列表。|offset|length|style|CODE|1492294|entityMap^0|0|0|2|1T|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

This function collect all matching sequences from string. In this example it takes all email addresses from string.

<pre><code>static final String EMAIL_PATTERN = "[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@"
 + "[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})";

public List&lt;String&gt; getAllEmails(String message) { 
 List&lt;String&gt; result = null;
 Matcher matcher = Pattern.compile(EMAIL_PATTERN).matcher(message);

 if (matcher.find()) {
 result = new ArrayList&lt;String&gt;();
 result.add(matcher.group());

 while (matcher.find()) {
 result.add(matcher.group());
 }
 }

 return result;
}
</code></pre>

For <code>message = "adf@gmail.com, &lt;another@osiem.osiem&gt;&gt;&gt;&gt; lalala@aaa.pl"</code> it will create List of 3 elements.

blocks|key|1707331|text|有时，您可以使用java.lang.String中提供的简单.split("REGEXP")方法。例如：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1707332|String+input+=+"first,second,third";

//To+retrieve+'first'+
input.split(",")[0]+
//second
input.split(",")[1]
//third
input.split(",")[2]|code-block|syntax|javascript|1707333|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Sometimes you can use simple .split("REGEXP") method available in java.lang.String. For example: 

<pre><code>String input = "first,second,third";

//To retrieve 'first' 
input.split(",")[0] 
//second
input.split(",")[1]
//third
input.split(",")[2]
</code></pre>

blocks|key|1707375|text|如果你正在从文件中读取，那么这可以帮助你|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1707376|++++++++++++++try{
+++++++++++++InputStream+inputStream+=+(InputStream)+mnpMainBean.getUploadedBulk().getInputStream();
+++++++++++++BufferedReader+br+=+new+BufferedReader(new+InputStreamReader(inputStream));
+++++++++++++String+line;
+++++++++++++//Ref:03
+++++++++++++while+((line+=+br.readLine())+!=+null)+{
++++++++++++++++if+(line.matches("[A-Z],\\d,(\\d*,){2}(\\s*\\d*\\%7C\\d*:)%2B"))+{
+++++++++++++++++++++String[]+splitRecord+=+line.split(",");
+++++++++++++++++++++//do+something
+++++++++++++++++}
+++++++++++++++++else{
+++++++++++++++++++++br.close();
+++++++++++++++++++++//error
+++++++++++++++++++++return;
+++++++++++++++++}
+++++++++++++}
++++++++++++++++br.close();

+++++++++++++}
+++++++++}
+++++++++catch+(IOException++ioExpception){
+++++++++++++logger.logDebug("Exception+"+%2B+ioExpception.getStackTrace());
+++++++++}|code-block|syntax|javascript|1707377|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

if you are reading from file then this can help you

<pre><code> try{
 InputStream inputStream = (InputStream) mnpMainBean.getUploadedBulk().getInputStream();
 BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));
 String line;
 //Ref:03
 while ((line = br.readLine()) != null) {
 if (line.matches("[A-Z],\\d,(\\d*,){2}(\\s*\\d*\\|\\d*:)+")) {
 String[] splitRecord = line.split(",");
 //do something
 }
 else{
 br.close();
 //error
 return;
 }
 }
 br.close();

 }
 }
 catch (IOException ioExpception){
 logger.logDebug("Exception " + ioExpception.getStackTrace());
 }
</code></pre>

blocks|key|1492441|text|简单解决方案|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1492442|//+Regexplanation:
//+%5E+++++++beginning+of+line
//+\\D%2B++++1%2B+non-digit+characters
//+(\\d%2B)++1%2B+digit+characters+in+a+capture+group
//+.*++++++0%2B+any+character
String+regexStr+=+"%5E\\D%2B(\\d%2B).*";

//+Compile+the+regex+String+into+a+Pattern
Pattern+p+=+Pattern.compile(regexStr);

//+Create+a+matcher+with+the+input+String
Matcher+m+=+p.matcher(inputStr);

//+If+we+find+a+match
if+(m.find())+{
++++//+Get+the+String+from+the+first+capture+group
++++String+someDigits+=+m.group(1);
++++//+...do+something+with+someDigits
}|code-block|syntax|javascript|1492443|Util类中的解决方案|1492444|public+class+MyUtil+{
++++private+static+Pattern+pattern+=+Pattern.compile("%5E\\D%2B(\\d%2B).*");
++++private+static+Matcher+matcher+=+pattern.matcher("");

++++//+Assumptions:+inputStr+is+a+non-null+String
++++public+static+String+extractFirstNumber(String+inputStr){
++++++++//+Reset+the+matcher+with+a+new+input+String
++++++++matcher.reset(inputStr);

++++++++//+Check+if+there's+a+match
++++++++if(matcher.find()){
++++++++++++//+Return+the+number+(in+the+first+capture+group)
++++++++++++return+matcher.group(1);
++++++++}else{
++++++++++++//+Return+some+default+value,+if+there+is+no+match
++++++++++++return+null;
++++++++}
++++}
}

...

//+Use+the+util+function+and+print+out+the+result
String+firstNum+=+MyUtil.extractFirstNumber("Testing4234Things");
System.out.println(firstNum);|1492445|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<h2>Simple Solution</h2>

<pre><code>// Regexplanation:
// ^ beginning of line
// \\D+ 1+ non-digit characters
// (\\d+) 1+ digit characters in a capture group
// .* 0+ any character
String regexStr = "^\\D+(\\d+).*";

// Compile the regex String into a Pattern
Pattern p = Pattern.compile(regexStr);

// Create a matcher with the input String
Matcher m = p.matcher(inputStr);

// If we find a match
if (m.find()) {
 // Get the String from the first capture group
 String someDigits = m.group(1);
 // ...do something with someDigits
}
</code></pre>

<h2>Solution in a Util Class</h2>

<pre><code>public class MyUtil {
 private static Pattern pattern = Pattern.compile("^\\D+(\\d+).*");
 private static Matcher matcher = pattern.matcher("");

 // Assumptions: inputStr is a non-null String
 public static String extractFirstNumber(String inputStr){
 // Reset the matcher with a new input String
 matcher.reset(inputStr);

 // Check if there's a match
 if(matcher.find()){
 // Return the number (in the first capture group)
 return matcher.group(1);
 }else{
 // Return some default value, if there is no match
 return null;
 }
 }
}

...

// Use the util function and print out the result
String firstNum = MyUtil.extractFirstNumber("Testing4234Things");
System.out.println(firstNum);
</code></pre>

blocks|key|1492452|text|Pattern+p+=+Pattern.compile("(\\D%2B)(\\d%2B)(.*)");
Matcher+m+=+p.matcher("this+is+your+number:1234+thank+you");
if+(m.find())+{
++++String+someNumberStr+=+m.group(2);
++++int+someNumberInt+=+Integer.parseInt(someNumberStr);
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1492453|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>Pattern p = Pattern.compile("(\\D+)(\\d+)(.*)");
Matcher m = p.matcher("this is your number:1234 thank you");
if (m.find()) {
 String someNumberStr = m.group(2);
 int someNumberInt = Integer.parseInt(someNumberStr);
}
</code></pre>

I have several strings in the rough form:

<pre><code>[some text] [some number] [some more text]
</code></pre>

I want to extract the text in [some number] using the Java Regex classes.

I know roughly what regular expression I want to use (though all suggestions are welcome). What I'm really interested in are the Java calls to take the regex string and use it on the source data to produce the value of [some number].

EDIT: I should add that I'm only interested in a single [some number] (basically, the first instance). The source strings are short and I'm not going to be looking for multiple occurrences of [some number].

Using Regular Expressions to Extract a Value in Java

Java

我有几个粗略形式的字符串：[some text] [some number] [some more text]我想使用Java Regex类提取一些数字形式的文本。我大致知道我想要使用什么正则表达式(尽管欢迎所有建议)。我真正感兴趣的是Java调用，以获取正则表达式字符串，并在源数据上使用它来生成某个数字的值。编辑:我...

问在Java中使用正则表达式提取值
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