This question already has answers here:
Java generating Strings with placeholders
(12 answers)
Closed 4 years ago.
The client passed me a parameter str = "${param0},${param1}".
I want to replace ${param0} ${param1} with the value I queried from the database.
such as
//str = "${param0},${param1}"
//str = "${param0},${param1}, ${param2}"
//...
public String format(String str) {
String param0 = repository.query0();
//expect
str = "param0,${param1}";
String param1 = repository.query1();
//expect
str = "param0,param1,${param2}";
return str;
}
I know that java.lang.String#replace can solve the problem. But the parameter str is indefinite. It could also be str = "${param0}, ${param1}, ${param2}" or more. Is there any way to satisfy my request?
If you can be confident that it will always be in the format of ${paramX} then you can do the following:
String str = ...;
for (int i = 0; i < results.length; i++)
{
str = str.replace("${param" + i + "}", results[i]);
}
Replace the contents of the for loop and the resutls[i] portion to be however you access the data returned from your query.
If you instead can't dependent on ${paramX} being in sequential order, you can use a more hacky solution by using the following code:
// create a new StringBuilder to reduce concatentation
StringBuilder result = new StringBuilder();
// our warped string input
String str = "${param0}, ${param12}${param1234}${param2}";
// split it anywhere that is formatted with ${paramXXXX}
String[] parts = str.split("\\$\\{param[0-9]{1,}\\}");
// loop through the pieces
for (int i = 0; i < parts.length; i++)
{
// get the parts of the string that are not ${paramXXXX}
result.append(parts[i]);
// the results from the query.
result.append(queryResults[i]); // Replace with the proper way to read your query results
}
The above code should work no matter the input, as long as there are the same number of query results as there are ${paramXXXX} pieces in the input string.
Be sure to replace the code followed by // Replace with ... with the code to read your query results.
Here is an approach using matcher:
String str = "${param0},${param1}, ${param2}";
System.out.println("Matching: "+str);
Pattern regex = Pattern.compile("\\$\\{(\\w+)\\}");
Matcher matcher = regex.matcher(str);
while (matcher.find()){
System.out.println("found: "+matcher.group());
str = matcher.replaceFirst("results");
matcher = regex.matcher(str);
}
System.out.println("Result: "+str);
This is not very efficient, but easy to use. If you have gigabyte-scale computations, consider looping over your input string and compare characters manually.
Update:
Here is a better approach. More efficient and not susceptible for endless loop if results contain the pattern.
String str = "[${param0},${param1}, ${param2}]";
System.out.println("Matching: " + str);
final Pattern regex = Pattern.compile("\\$\\{(\\w+)\\}");
final Matcher matcher = regex.matcher(str);
final StringBuilder sb = new StringBuilder(str.length());
int prevMatch = 0;
while (matcher.find()) {
System.out.println("found: " + matcher.group());
sb.append(str.substring(prevMatch, matcher.start()));
sb.append("results");
prevMatch = matcher.end();
}
sb.append(str.substring(prevMatch, str.length()));
System.out.println("Result: " + sb.toString());
Related
We need to find the length of the tag names within the tags in java
{Student}{Subject}{Marks}100{/Marks}{/Subject}{/Student}
so the length of Student tag is 7 and that of subject tag is 7 and that of marks is 5.
I am trying to split the tags and then find the length of each string within the tag.
But the code I am trying gives me only the first tag name and not others.
Can you please help me on this?
I am very new to java. Please let me know if this is a very silly question.
Code part:
System.out.println(
getParenthesesContent("{Student}{Subject}{Marks}100{/Marks}{/Subject}{/Student}"));
public static String getParenthesesContent(String str) {
return str.substring(str.indexOf('{')+1,str.indexOf('}'));
}
You can use Patterns with this regex \\{(\[a-zA-Z\]*)\\} :
String text = "{Student}{Subject}{Marks}100{/Marks}{/Subject}{/Student}";
Matcher matcher = Pattern.compile("\\{([a-zA-Z]*)\\}").matcher(text);
while (matcher.find()) {
System.out.println(
String.format(
"tag name = %s, Length = %d ",
matcher.group(1),
matcher.group(1).length()
)
);
}
Outputs
tag name = Student, Length = 7
tag name = Subject, Length = 7
tag name = Marks, Length = 5
You might want to give a try to another regex:
String s = "{Abc}{Defg}100{Hij}100{/Klmopr}{/Stuvw}"; // just a sample String
Pattern p = Pattern.compile("\\{\\W*(\\w++)\\W*\\}");
Matcher m = p.matcher(s);
while(m.find()) {
System.out.println(m.group(1) + ", length: " + m.group(1).length());
}
Output you get:
Abc, length: 3
Defg, length: 4
Hij, length: 3
Klmopr, length: 6
Stuvw, length: 5
If you need to use charAt() to walk over the input String, you might want to consider using something like this (I made some explanations in the comments to the code):
String s = "{Student}{Subject}{Marks}100{/Marks}{/Subject}{/Student}";
ArrayList<String> tags = new ArrayList<>();
for(int i = 0; i < s.length(); i++) {
StringBuilder sb = new StringBuilder(); // Use StringBuilder and its append() method to append Strings (it's more efficient than "+=") String appended = ""; // This String will be appended when correct tag is found
if(s.charAt(i) == '{') { // If start of tag is found...
while(!(Character.isLetter(s.charAt(i)))) { // Skip characters that are not letters
i++;
}
while(Character.isLetter(s.charAt(i))) { // Append String with letters that are found
sb.append(s.charAt(i));
i++;
}
if(!(tags.contains(sb.toString()))) { // Add final String to ArrayList only if it not contained here yet
tags.add(sb.toString());
}
}
}
for(String tag : tags) { // Printing Strings contained in ArrayList and their length
System.out.println(tag + ", length: " + tag.length());
}
Output you get:
Student, length: 7
Subject, length: 7
Marks, length: 5
yes use regular expression, find the pattern and apply that.
I'm trying to match exact AdvanceJava keyword with the given inputText string but it executes both if and else condition,instead of I want only AdvanceJava keyword matched.
String inputText = ("iwanttoknowrelatedtoAdvancejava").toLowerCase().replaceAll("\\s", "");
String match = "java";
List keywordsList = new ArrayList<>();//where keywordsList{advance,core,programming} -> keywordlist fetch
// from database
Enumeration e = Collections.enumeration(keywordsList);
int size = keywordsList.size();
while (e.hasMoreElements()) {
for (int i = 0; i < size; i++) {
String s1 = (String) keywordsList.get(i);
if (inputText.contains(s1) && inputText.contains(match)) {
System.out.println("Yes we providing " + s1);
} else if (!inputText.contains(s1) && inputText.contains(match)) {
System.out.println("Yes we are working on java");
}
}
break;
}
Thanks
you can simply do this by using pattern and matcher classes
Pattern p = Pattern.compile("java");
Matcher m = p.matcher("Print this");
m.find();
If you want to find multiple matches in a line, you can call find() and group() repeatedly to extract them all.
Here's how you can achieve what you seek using pattern matching.
In the first example I have taken your input text as it is. This only improves your algorithm which has O(n^2) performance.
String inputText = ("iwanttoknowrelatedtoAdvancejava").toLowerCase().replaceAll("\\s", "");
String match = "java";
List<String> keywordsList = Arrays.asList("advance", "core", "programming");
for (String keyword : keywordsList) {
Pattern p = Pattern.compile(keyword.concat(match));
Matcher m = p.matcher(inputText);
//System.out.println(m.find());
if (m.find()) {
System.out.println("Yes we are providing " + keyword.concat(match));
}
}
But we can improve this in to a better implementation. Here's a more generic version of the above implementation. This code doesn't manipulate the input text before matching, rather we provide a more generic regular expression which ignores spaces and matches case insensitive manner.
String inputText = "i want to know related to Advance java";
String match = "java";
List<String> keywordsList = Arrays.asList("advance", "core", "programming");
for (String keyword : keywordsList) {
Pattern p = Pattern.compile(MessageFormat.format("(?i)({0}\\s*{1})", keyword, match));
Pattern p1 = Pattern.compile(MessageFormat.format("(?i)({0})", match));
Matcher m = p.matcher(inputText);
Matcher m1 = p1.matcher(inputText);
//System.out.println(m.find());
if(m.find()) {
System.out.println("Yes we are providing " + keyword.concat(match));
} else if(m1.find()) {
System.out.println("Yes we are working with " + match);
}
}
#sithum - Thanks but it executes both condition of if else in output.Please refer Screen shot which I attached here.
I applied following logic and it works fine. please refer it , Thanks.
String inputText = ("iwanttoknowrelatedtoAdvancejava").toLowerCase().replaceAll("\\s", "");
String match = "java";
List<String> keywordsList = session.createSQLQuery("SELECT QUESTIONARIES_RAISED FROM QUERIES").list(); // Fetch values from database (advance,core,programming)
String uniqueKeyword=null;
String commonKeyword= null;
int size =keywordsList.size();
for(int i=0;i<size;i++){
String s1 = (String) keywordsList.get(i);//get values one by one from list
if(inputText.contains(match)){
if(inputText.contains(s1) && inputText.contains(match)){
Queries q1 = new Queries();
q1.setQuestionariesRaised(s1); //set matched keyword to getter setter method
keywordsList1=session.createQuery("from Queries sentence where questionariesRaised='"+q1.getQuestionariesRaised()+"'").list(); // based on matched keyword fetch according to matched keyword sentence which stored in database
for(Queries ob : keywordsList1){
uniqueKeyword= ob.getSentence().toString();// Store fetched sentence to on string variable
}
break;
}else {
commonKeyword= "java only";
}
}
}}
if(uniqueKeyword!= null){
System.out.println("Yes we providing......................" + uniqueKeyword);
}else if(commonKeyword!= null){
System.out.println("Yes we providing " + commonKeyword);
}else{
}
I am writing a small programming language for a game I am making, this language will be for allowing users to define their own spells for the wizard entity outside the internal game code. I have the language written down, but I'm not entirely sure how to change a string like
setSpellName("Fireball")
setSplashDamage(32,5)
into an array which would have the method name and the arguments after it, like
{"setSpellName","Fireball"}
{"setSplashDamage","32","5"}
How could I do this using java's String.split or string regex's?
Thanks in advance.
Since you're only interested in the function name and parameters I'd suggest scanning up to the first instance of ( and then to the last ) for the params, as so.
String input = "setSpellName(\"Fireball\")";
String functionName = input.substring(0, input.indexOf('('));
String[] params = input.substring(input.indexOf(')'), input.length - 1).split(",");
To capture the String
setSpellName("Fireball")
Do something like this:
String[] line = argument.split("(");
Gets you "setSpellName" at line[0] and "Fireball") at line[1]
Get rid of the last parentheses like this
line[1].replaceAll(")", " ").trim();
Build your JSON with the two "cleaned" Strings.
There's probably a better way with Regex, but this is the quick and dirty way.
With String.indexOf() and String.substring(), you can parse out the function and parameters. Once you parse them out, apply the quotes are around each of them. Then combine them all back together delimited by commas and wrapped in curly braces.
public static void main(String[] args) throws Exception {
List<String> commands = new ArrayList() {{
add("setSpellName(\"Fireball\")");
add("setSplashDamage(32,5)");
}};
for (String command : commands) {
int openParen = command.indexOf("(");
String function = String.format("\"%s\"", command.substring(0, openParen));
String[] parameters = command.substring(openParen + 1, command.indexOf(")")).split(",");
for (int i = 0; i < parameters.length; i++) {
// Surround parameter with double quotes
if (!parameters[i].startsWith("\"")) {
parameters[i] = String.format("\"%s\"", parameters[i]);
}
}
String combine = String.format("{%s,%s}", function, String.join(",", parameters));
System.out.println(combine);
}
}
Results:
{"setSpellName","Fireball"}
{"setSplashDamage","32","5"}
This is a solution using regex, use this Regex "([\\w]+)\\(\"?([\\w]+)\"?\\)":
String input = "setSpellName(\"Fireball\")";
String pattern = "([\\w]+)\\(\"?([\\w]+)\"?\\)";
Pattern r = Pattern.compile(pattern);
String[] matches;
Matcher m = r.matcher(input);
if (m.find()) {
System.out.println("Found value: " + m.group(1));
System.out.println("Found value: " + m.group(2));
String[] params = m.group(2).split(",");
if (params.length > 1) {
matches = new String[params.length + 1];
matches[0] = m.group(1);
System.out.println(params.length);
for (int i = 0; i < params.length; i++) {
matches[i + 1] = params[i];
}
System.out.println(String.join(" :: ", matches));
} else {
matches = new String[2];
matches[0] = m.group(1);
matches[1] = m.group(2);
System.out.println(String.join(", ", matches));
}
}
([\\w]+) is the first group to get the function name.
\\(\"?([\\w]+)\"?\\) is the second group to get the parameters.
This is a Working DEMO.
I've to replace a set of substrings in a String with another substrings for example
"^t" with "\t"
"^=" with "\u2014"
"^+" with "\u2013"
"^s" with "\u00A0"
"^?" with "."
"^#" with "\\d"
"^$" with "[a-zA-Z]"
So, I've tried with:
String oppip = "pippo^t^# p^+alt^shefhjkhfjkdgfkagfafdjgbcnbch^";
Map<String,String> tokens = new HashMap<String,String>();
tokens.put("^t", "\t");
tokens.put("^=", "\u2014");
tokens.put("^+", "\u2013");
tokens.put("^s", "\u00A0");
tokens.put("^?", ".");
tokens.put("^#", "\\d");
tokens.put("^$", "[a-zA-Z]");
String regexp = "^t|^=|^+|^s|^?|^#|^$";
StringBuffer sb = new StringBuffer();
Pattern p = Pattern.compile(regexp);
Matcher m = p.matcher(oppip);
while (m.find())
m.appendReplacement(sb, tokens.get(m.group()));
m.appendTail(sb);
System.out.println(sb.toString());
But it doesn't work. tokens.get(m.group()) throws an exception.
Any idea why?
You don't have to use a HashMap. Consider using simple arrays, and a loop:
String oppip = "pippo^t^# p^+alt^shefhjkhfjkdgfkagfafdjgbcnbch^";
String[] searchFor =
{"^t", "^=", "^+", "^s", "^?", "^#", "^$"},
replacement =
{"\\t", "\\u2014", "\\u2013", "\\u00A0", ".", "\\d", "[a-zA-Z]"};
for (int i = 0; i < searchFor.length; i++)
oppip = oppip.replace(searchFor[i], replacement[i]);
// Print the result.
System.out.println(oppip);
Here is an online code demo.
For the completeness, you can use a two-dimensional array for a similar approach:
String oppip = "pippo^t^# p^+alt^shefhjkhfjkdgfkagfafdjgbcnbch^";
String[][] tasks =
{
{"^t", "\\t"},
{"^=", "\\u2014"},
{"^+", "\\u2013"},
{"^s", "\\u00A0"},
{"^?", "."},
{"^#", "\\d"},
{"^$", "[a-zA-Z]"}
};
for (String[] replacement : tasks)
oppip = oppip.replace(replacement[0], replacement[1]);
// Print the result.
System.out.println(oppip);
In regex the ^ means "begin-of-text" (or "not" within a character class as negation). You have to place a backslash before it, which becomes two backslashes in a java String.
String regexp = "\\^[t=+s?#$]";
I have reduced it a bit further.
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
substring between two delimiters
I have a string like
"ABC[ This is to extract ]"
I want to extract the part "This is to extract" in java. I am trying to use split, but it is not working the way I want. Does anyone have suggestion?
If you have just a pair of brackets ( [] ) in your string, you can use indexOf():
String str = "ABC[ This is the text to be extracted ]";
String result = str.substring(str.indexOf("[") + 1, str.indexOf("]"));
If there is only 1 occurrence, the answer of ivanovic is the best way I guess. But if there are many occurrences, you should use regexp:
\[(.*?)\] this is your pattern. And in each group(1) will get you your string.
Pattern p = Pattern.compile("\\[(.*?)\\]");
Matcher m = p.matcher(input);
while(m.find())
{
m.group(1); //is your string. do what you want
}
Try as
String s = "ABC[ This is to extract ]";
Pattern p = Pattern.compile(".*\\[ *(.*) *\\].*");
Matcher m = p.matcher(s);
m.find();
String text = m.group(1);
System.out.println(text);
String s = "ABC[This is to extract]";
System.out.println(s);
int startIndex = s.indexOf('[');
System.out.println("indexOf([) = " + startIndex);
int endIndex = s.indexOf(']');
System.out.println("indexOf(]) = " + endIndex);
System.out.println(s.substring(startIndex + 1, endIndex));