In this article, we will discuss StringBuffer’s substring() method which is used to get substring (partial string or portion of string from StringBuffer as per specified range)
1. StringBuffer’s substring() method:
- This StringBuffer method is used to get sub-string for the specified begin-indexand end-index
- There are 2 variants or overloaded substring() method,
- 1st variant returns substring starting from specified index-position till length
- 2nd variant returns substring starting from specified index-position to specified end index-position
- In addition to this, there is one more StringBuffer method similar to 2nd variant i.e.; subSequence() method
1.1 Method Signature:
public String substring(int start);
public String substring(int start, int end);
public CharSequence subSequence(int start, int end);
1.2 Parameters:
- Start –> start index (indicates from where string need to be extracted and it is inclusive)
- end –> end index (indicates till where string need to be extracted and it is exclusive)
1.3 Returns:
| substring() method |
Returns |
| public String substring(int start); | Returns substring from the invoking StringBuffer object, starting from specified begin-index |
| public String substring(int start, int end); | Returns substring from the invoking StringBuffer object, starting from specified begin-index till end-index |
| public CharSequence subSequence(int start, int end); | Very similar to substring(beginIndex, endIndex);
Returns char sequence from the invoking StringBuffer object, starting from specified begin-index till end-index |
1.4 Throws:
- substring() method throws StringIndexOutOfBoundsException, if index value passed falls out of range i.e.;
- if either start-index or end-index is negative (<0)
- if start-index is greater than end-index
- if end-index is greater than length()
- subsequence() method throws IndexOutOfBoundsException, if index value passed falls out of range i.e.;
- if either start-index or end-index is negative (<0)
- if start-index is greater than end-index
- if end-index is greater than length()
2. Examples on substring() method:
2.1 To get sub-string starting from specified begin-index
Method Signature:
public String substring(int start);
StringBufferSubstringMethod.java
package in.bench.resources.stringbuffer.methods;
public class StringBufferSubstringMethod {
public static void main(String[] args) {
// StringBuffer 1: to get substring() -
// starting from 10th index-position
StringBuffer sb1 = new StringBuffer(
"Java is a super cool language");
String subString1 = sb1.substring(10);
System.out.println("sb1.substring(10) is : "
+ subString1);
// StringBuffer 2: to get substring() -
// starting from 24th index-position
StringBuffer sb2 = new StringBuffer(
"BenchResources.Net ");
sb2.append("is a Java weblog"); // 1st append
String subString2 = sb2.substring(24);
System.out.println("\nsb2.substring(24) is : "
+ subString2);
// StringBuffer 3: to get substring() -
// starting from 13th index-position
StringBuffer sb3 = new StringBuffer(
"String class ");
sb3.append("has useful "); // 1st append
sb3.append("methods"); // 2nd append
String subString3 = sb3.substring(13);
System.out.println("\nsb3.substring(13) is : "
+ subString3);
}
}
Output:
sb1.substring(10) is : super cool language
sb2.substring(24) is : Java weblog
sb3.substring(13) is : has useful methods
2.2 To get substring starting from specified begin-index till specified end-index
Method Signature:
public String substring(int start, int end);
StringBufferSubstringMethod2.java
package in.bench.resources.stringbuffer.methods;
public class StringBufferSubstringMethod2 {
public static void main(String[] args) {
// StringBuffer 1: to get substring() -
// starting from 10th till 20th index-position
StringBuffer sb1 = new StringBuffer(
"Java is a super cool language");
String subString1 = sb1.substring(10, 20);
System.out.println("sb1.substring(10, 20) is : "
+ subString1);
// StringBuffer 2: to get substring() -
// starting from 24th till 28th index-position
StringBuffer sb2 = new StringBuffer(
"BenchResources.Net ");
sb2.append("is a Java weblog"); // 1st append
String subString2 = sb2.substring(24, 28);
System.out.println("\nsb2.substring(24, 28) is : "
+ subString2);
// StringBuffer 3: to get substring() -
// starting from 7th till 23rd index-position
StringBuffer sb3 = new StringBuffer(
"String class ");
sb3.append("has useful "); // 1st append
sb3.append("methods"); // 2nd append
String subString3 = sb3.substring(07, 23);
System.out.println("\nsb3.substring(07, 23) is : "
+ subString3);
}
}
Output:
sb1.substring(10, 20) is : super cool
sb2.substring(24, 28) is : Java
sb3.substring(07, 23) is : class has useful
2.3 To get char sequence starting from specified begin-index till specified end-index
- Note: very similar to substring(beginIndex, endIndex);
Method Signature:
public CharSequence subSequence(int start, int end);
StringBufferSubsequenceMethod.java
package in.bench.resources.stringbuffer.methods;
public class StringBufferSubsequenceMethod {
public static void main(String[] args) {
// Example 1: to get subSequence() -
// starting from 10th till 20th index-position
StringBuffer sb1 = new StringBuffer(
"Java is a super cool language");
CharSequence charSequence1 = sb1.substring(10, 20);
System.out.println("sb1.subSequence(10, 20) is : "
+ charSequence1);
// Example 2: to get subSequence() -
// starting from 24th till 28th index-position
StringBuffer sb2 = new StringBuffer(
"BenchResources.Net ");
sb2.append("is a Java weblog"); // 1st append
CharSequence charSequence2 = sb2.subSequence(24, 28);
System.out.println("\nsb2.subSequence(24, 28) is : "
+ charSequence2);
// Example 3: to get subSequence() -
// starting from 7th till 23rd index-position
StringBuffer sb3 = new StringBuffer(
"String class ");
sb3.append("has useful "); // 1st append
sb3.append("methods"); // 2nd append
CharSequence charSequence3 = sb3.subSequence(07, 23);
System.out.println("\nsb3.subSequence(07, 23) is : "
+ charSequence3);
}
}
Output:
sb1.subSequence(10, 20) is : super cool
sb2.subSequence(24, 28) is : Java
sb3.subSequence(07, 23) is : class has useful
Related Articles:
- Java – StringBuffer class
- Java – StringBuffer append() method (13)
- Java – StringBuffer capacity() method
- Java – StringBuffer charAt(int index) method
- Java – StringBuffer delete(int start, int end) method
- Java – StringBuffer deleteCharAt(int index) method
- Java – StringBuffer ensureCapacity(int minimumCapacity) method
- Java – StringBuffer indexOf() method (2)
- Java – StringBuffer insert() method (12)
- Java – StringBuffer lastIndexOf() method (2)
- Java – StringBuffer length() method
- Java – StringBuffer replace(int start, int end, String str) method
- Java – StringBuffer reverse() method
- Java – StringBuffer substring(int start, int end) method
References:
- https://docs.oracle.com/javase/tutorial/essential/concurrency/immutable.html
- https://docs.oracle.com/javase/tutorial/essential/concurrency/imstrat.html
- https://docs.oracle.com/javase/tutorial/java/data/strings.html
- https://docs.oracle.com/javase/8/docs/api/java/lang/String.html
- https://docs.oracle.com/javase/8/docs/api/java/lang/class-use/String.html
- https://docs.oracle.com/javase/8/docs/api/java/lang/StringBuffer.html
- https://docs.oracle.com/javase/8/docs/api/java/lang/StringBuilder.html
Happy Coding !!
Happy Learning !!
