In this article, we will discuss StringBuilder’s append() method which internally converts respective data-type into String format first and then append to buffer at the very end
1. StringBuilder’s append() method :
- This method is used to append given argument of any data-type at the end of buffer
- Note: There are 13 variants or overloaded append() method, those are,
1.1 Method Signature:
public StringBuilder append(boolean b);
public StringBuilder append(char c)
public StringBuilder append(int i);
public StringBuilder append(long lng);
public StringBuilder append(float f);
public StringBuilder append(double d);
public StringBuilder append(char[] str);
public StringBuilder append(char[] str, int offset, int len);
public StringBuilder append(CharSequence s);
public StringBuilder append(CharSequence s, int start, int end);
public StringBuilder append(Object obj);
public StringBuilder append(String str);
public StringBuilder append(StringBuffer sb);
1.2 Returns:
- Returns StringBuilder object after appending given argument at the end of the buffer
- Argument can be any primitive data-types like boolean, char, int, long, float, double, etc.
- It can also be used to append char[] array, CharSequence, Object or String and StringBuffer
2. Examples on append() method:
2.1 To append specified primitive boolean data-type into StringBuilder object
Method signature:
public StringBuilder append(boolean b);
StringBuilderAppendMethodForBoolean.java
package in.bench.resources.stringbuilder.methods;
public class StringBuilderAppendMethodForBoolean {
public static void main(String[] args) {
// define boolean variable
boolean boolTest1 = true;
boolean boolTest2 = false;
// 1. appending boolean to StringBuilder
// using append(boolean) method
StringBuilder sb1 = new StringBuilder("This is ");
sb1.append(boolTest1);
// 2. appending boolean to StringBuilder
// using append(boolean) method
StringBuilder sb2 = new StringBuilder("It is ");
sb2.append(boolTest2);
// print to console - internally invokes toString() method
System.out.println("1. Appending boolean TRUE"
+ " to StringBuilder : " + sb1);
System.out.println("2. Appending boolean FALSE"
+ " to StringBuilder : " + sb2);
}
}
Output:
1. Appending boolean TRUE to StringBuilder : This is true
2. Appending boolean FALSE to StringBuilder : It is false
2.2 To append specified primitive int data-type into StringBuilder object
Method signature:
public StringBuilder append(int i);
StringBuilderAppendMethodForInteger.java
package in.bench.resources.stringbuilder.methods;
public class StringBuilderAppendMethodForInteger {
public static void main(String[] args) {
// define int variable
int iTest1 = 19;
int iTest2 = 333;
// 1. appending int value to StringBuilder
// using append(int) method
StringBuilder sb1 = new StringBuilder(
"Integer number is ");
sb1.append(iTest1);
// 2. appending int value to StringBuilder
// using append(int) method
StringBuilder sb2 = new StringBuilder(
"Other int number is ");
sb2.append(iTest2);
// print to console - internally invokes toString() method
System.out.println("1. Appending int value"
+ " to StringBuilder : " + sb1);
System.out.println("2. Appending int value"
+ " to StringBuilder : " + sb2);
}
}
Output:
1. Appending int value to StringBuilder : Integer number is 19
2. Appending int value to StringBuilder : Other int number is 333
2.3 To append specified primitive long data-type into StringBuilder object
Method signature:
public StringBuilder append(long lng);
StringBuilderAppendMethodForLong.java
package in.bench.resources.stringbuilder.methods;
public class StringBuilderAppendMethodForLong {
public static void main(String[] args) {
// define int variable
long lngTest1 = 1912345;
long lngTest2 = 333444999;
// 1. appending long value to StringBuilder
// using append(long) method
StringBuilder sb1 = new StringBuilder(
"The appended long vale is ");
sb1.append(lngTest1);
// 2. appending long value to StringBuilder
// using append(long) method
StringBuilder sb2 = new StringBuilder(
"Other appended long vale is ");
sb2.append(lngTest2);
// print to console - internally invokes toString() method
System.out.println("1. Appending long value"
+ " to StringBuilder : " + sb1);
System.out.println("2. Appending long value"
+ " to StringBuilder : " + sb2);
}
}
Output:
1. Appending long value to StringBuilder :
The appended long vale is 1912345
2. Appending long value to StringBuilder :
Other appended long vale is 333444999
2.4 To append specified primitive float data-type into StringBuilder object
Method signature:
public StringBuilder append(float f);
StringBuilderAppendMethodForFloat.java
package in.bench.resources.stringbuilder.methods;
public class StringBuilderAppendMethodForFloat {
public static void main(String[] args) {
// define float variable
float ftTest1 = 19.23456f;
float ftTest2 = 258.589635f;
// 1. appending float value to StringBuilder
// using append(float) method
StringBuilder sb1 = new StringBuilder(
"The float value is ");
sb1.append(ftTest1);
// 2. appending float value to StringBuilder
// using append(float) method
StringBuilder sb2 = new StringBuilder(
"Other float value is ");
sb2.append(ftTest2);
// print to console - internally invokes toString() method
System.out.println("1. Appending float value"
+ " to StringBuilder : " + sb1);
System.out.println("2. Appending float value"
+ " to StringBuilder : " + sb2);
}
}
Output:
1. Appending float value to StringBuilder :
The float value is 19.23456
2. Appending float value to StringBuilder :
Other float value is 258.58963
2.5 To append specified primitive double data-type into StringBuilder object
Method signature:
public StringBuilder append(double d);
StringBuilderAppendMethodForDouble.java
package in.bench.resources.stringbuilder.methods;
public class StringBuilderAppendMethodForDouble {
public static void main(String[] args) {
// define double variable
double dblTest1 = 19.23456;
double dblTest2 = 258.589635;
// 1. appending double value to StringBuilder
// using append(double) method
StringBuilder sb1 = new StringBuilder(
"The double value is ");
sb1.append(dblTest1);
// 2. appending double value to StringBuilder
// using append(double) method
StringBuilder sb2 = new StringBuilder(
"Another double value is ");
sb2.append(dblTest2);
// print to console - internally invokes toString() method
System.out.println("1. Appending double value"
+ " to StringBuilder : " + sb1);
System.out.println("2. Appending double value"
+ " to StringBuilder : " + sb2);
}
}
Output:
1. Appending double value to StringBuilder :
The double value is 19.23456
2. Appending double value to StringBuilder :
Another double value is 258.589635
2.6 To append specified primitive char data-type into StringBuilder object
Method signature:
public StringBuilder append(char c);
StringBuilderAppendMethodForChar.java
package in.bench.resources.stringbuilder.methods;
public class StringBuilderAppendMethodForChar {
public static void main(String[] args) {
// define char variable
char chTest1 = 'A';
char chTest2 = 'b';
// 1. appending char value to StringBuilder
// using append(char) method
StringBuilder sb1 = new StringBuilder(
"Upper-case char value is ");
sb1.append(chTest1);
// 2. appending char value to StringBuilder
// using append(char) method
StringBuilder sb2 = new StringBuilder(
"Lower-case char value is ");
sb2.append(chTest2);
// print to console - internally invokes toString() method
System.out.println("1. Appending char value"
+ " to StringBuilder : " + sb1);
System.out.println("2. Appending char value"
+ " to StringBuilder : " + sb2);
}
}
Output:
1. Appending char value to StringBuilder :
Upper-case char value is A
2. Appending char value to StringBuilder :
Lower-case char value is b
2.7 To append specified char[] array into StringBuilder object
Method signature:
public StringBuilder append(char[] str);
public StringBuilder append(char[] str, int offset, int len);
StringBuilderAppendMethodForCharArray.java
package in.bench.resources.stringbuilder.methods;
public class StringBuilderAppendMethodForCharArray {
public static void main(String[] args) {
// define char[] variable
char[] chArrayTest1 = {'G', 'o', 'o', 'g', 'l', 'e'};
char[] chArrayTest2 = {'O', 'r', 'a', 'c', 'l', 'e'};
// 1. appending char[] value to StringBuilder
// using append(char[]) method
StringBuilder sb1 = new StringBuilder();
sb1.append(chArrayTest1);
// 2. appending char[] value to StringBuilder
// using append(char[]) method
StringBuilder sb2 = new StringBuilder();
sb2.append(chArrayTest2);
// print to console - internally invokes toString() method
System.out.println("1. Appending char[] value"
+ " to StringBuilder : " + sb1);
System.out.println("2. Appending char[] value"
+ " to StringBuilder : " + sb2);
}
}
Output:
1. Appending char[] value to StringBuilder : Google
2. Appending char[] value to StringBuilder : Oracle
2.8 To append specified CharSequence into StringBuilder object
Method signature:
public StringBuilder append(CharSequence s);
public StringBuilder append(CharSequence s, int start, int end);
StringBuilderAppendMethodForCharSequence.java
package in.bench.resources.stringbuilder.methods;
public class StringBuilderAppendMethodForCharSequence {
public static void main(String[] args) {
// define CharSequence variable
CharSequence charSeq1 = "Bench";
CharSequence charSeq2 = "Resources";
// 1. appending CharSequence value to StringBuilder
// using append(CharSequence) method
StringBuilder sb1 = new StringBuilder();
sb1.append(charSeq1);
// 2. appending CharSequence value to StringBuilder
// using append(CharSequence) method
StringBuilder sb2 = new StringBuilder();
sb2.append(charSeq2);
// print to console - internally invokes toString() method
System.out.println("1. Appending CharSequence value"
+ " to StringBuilder : " + sb1);
System.out.println("2. Appending CharSequence value"
+ " to StringBuilder : " + sb2);
}
}
Output:
1. Appending CharSequence value to StringBuilder : Bench
2. Appending CharSequence value to StringBuilder : Resources
2.9 To append specified String object into StringBuilder object
Method signature:
public StringBuilder append(Object obj);
public StringBuilder append(String str);
StringBuilderAppendMethodForStringObject.java
package in.bench.resources.stringbuilder.methods;
public class StringBuilderAppendMethodForStringObject {
public static void main(String[] args) {
// define String variable
String str1 = "Michigan";
String str2 = "University";
// 1. appending String value to StringBuilder
// using append(String) method
StringBuilder sb1 = new StringBuilder("University of ");
sb1.append(str1);
// 2. appending String value to StringBuilder
// using append(String) method
StringBuilder sb2 = new StringBuilder("Mumbai ");
sb2.append(str2);
// print to console - internally invokes toString() method
System.out.println("1. Appending String value"
+ " to StringBuilder : " + sb1);
System.out.println("2. Appending String value"
+ " to StringBuilder : " + sb2);
}
}
Output:
1. Appending String value to StringBuilder : University of Michigan
2. Appending String value to StringBuilder : Mumbai University
2.10 To append specified StringBuffer object into StringBuilder object
Method signature:
public StringBuilder append(StringBuffer sb);
StringBuilderAppendMethod.java
package in.bench.resources.stringbuilder.methods;
public class StringBuilderAppendMethod {
public static void main(String[] args) {
// create StringBuilder object
StringBuilder sbuilder = new StringBuilder(
"First StringBuilder object");
sbuilder.append(" created. ");
// create StringBuffer object
StringBuffer sbuffer = new StringBuffer(
"StringBuilder object ");
sbuffer.append("appended to the StringBuiider object.");
// appending StringBuffer to StringBuilder
// using append(StringBuffer) method
sbuilder.append(sbuffer);
// print to console - internally invokes toString() method
System.out.println("Appending StringBuffer value"
+ " to StringBuilder : \n\n"
+ sbuilder);
}
}
Output:
Appending StringBuffer value to StringBuilder :
First StringBuilder object created.
StringBuilder object appended to the StringBuiider object.
Related Articles:
- Java – StringBuilder class
- Java – StringBuilder append() method (13)
- Java – StringBuilder capacity() method
- Java – StringBuilder charAt(int index) method
- Java – StringBuilder delete(int start, int end) method
- Java – StringBuilder deleteCharAt(int index) method
- Java – StringBuilder ensureCapacity(int minimumCapacity) method
- Java – StringBuilder indexOf() method (2)
- Java – StringBuilder insert() method (12)
- Java – StringBuilder lastIndexOf() method (2)
- Java – StringBuilder length() method
- Java – StringBuilder replace(int start, int end, String str) method
- Java – StringBuilder reverse() method
- Java – StringBuilder 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 !!
