Insert(): add data in the middle of a StringBuffer

The insert( ) method inserts one string into another. It is overloaded to accept values of all the simple types, plus Strings, Objects, and CharSequences. It calls String.valueOf( ) to obtain the string representation of the value it is called with.

StringBuffer insert(int offset, boolean b): Inserts the boolean argument into this sequence.
StringBuffer insert(int offset, char c): Inserts the char argument into this sequence.
StringBuffer insert(int offset, char[] str): Inserts the char array argument into this sequence.
StringBuffer insert(int index, char[] str, int offset, int len): Inserts a subarray of the str array argument into this sequence.
StringBuffer insert(int dstOffset, CharSequence s): Inserts CharSequence into this sequence.
StringBuffer insert(int dstOffset, CharSequence s, int start, int end): Inserts a subsequence of the specified CharSequence into this sequence.
StringBuffer insert(int offset, double d): Inserts the double argument into this sequence.
StringBuffer insert(int offset, float f): Inserts the float argument into this sequence.
StringBuffer insert(int offset, int i): Inserts the second int argument into this sequence.
StringBuffer insert(int offset, long l): Inserts the long argument into this sequence.
StringBuffer insert(int offset, Object obj): Inserts the Object argument into this character sequence.
StringBuffer insert(int offset, String str): Inserts str.


public class Main {
  public static void main(String[] argv) {
    StringBuffer sb = new StringBuffer();
    sb.append(true);
    sb.append("java2s.com");
    sb.append(1.2);
    sb.append('a');
    
    sb.insert(3,"JAVA@S.COM");
    System.out.println(sb.toString());
  }
}

The output:


truJAVA@S.COMejava2s.com1.2a

The following sample program inserts strings:

 
public class Main {
  public static void main(String args[]) {
    StringBuffer sb = new StringBuffer("java2s.com");
    sb.insert(2, "like ");
    System.out.println(sb);
  }
}

The output of this example is shown here:


jalike va2s.com


public class Main {
  public static void main(String args[]) {
    Object objectRef = "hello";
    String string = "goodbye";
    char charArray[] = { 'a', 'b', 'c', 'd', 'e', 'f' };
    boolean booleanValue = true;
    char characterValue = 'K';
    int integerValue = 7;
    long longValue = 10000000;
    float floatValue = 2.5f;
    double doubleValue = 33.3;

    StringBuffer buffer = new StringBuffer();

    buffer.insert(0, objectRef);
    buffer.insert(0, "  ");
    buffer.insert(0, string);
    buffer.insert(0, "  ");
    buffer.insert(0, charArray);
    buffer.insert(0, "  ");
    buffer.insert(0, charArray, 3, 3);
    buffer.insert(0, "  ");
    buffer.insert(0, booleanValue);
    buffer.insert(0, "  ");
    buffer.insert(0, characterValue);
    buffer.insert(0, "  ");
    buffer.insert(0, integerValue);
    buffer.insert(0, "  ");
    buffer.insert(0, longValue);
    buffer.insert(0, "  ");
    buffer.insert(0, floatValue);
    buffer.insert(0, "  ");
    buffer.insert(0, doubleValue);

    System.out.printf("buffer after inserts:\n%s\n\n", buffer.toString());

  }
}

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