String append byte java

Class StringBuilder

A mutable sequence of characters. This class provides an API compatible with StringBuffer , but with no guarantee of synchronization. This class is designed for use as a drop-in replacement for StringBuffer in places where the string buffer was being used by a single thread (as is generally the case). Where possible, it is recommended that this class be used in preference to StringBuffer as it will be faster under most implementations.

The principal operations on a StringBuilder are the append and insert methods, which are overloaded so as to accept data of any type. Each effectively converts a given datum to a string and then appends or inserts the characters of that string to the string builder. The append method always adds these characters at the end of the builder; the insert method adds the characters at a specified point.

For example, if z refers to a string builder object whose current contents are » start «, then the method call z.append(«le») would cause the string builder to contain » startle «, whereas z.insert(4, «le») would alter the string builder to contain » starlet «.

In general, if sb refers to an instance of a StringBuilder , then sb.append(x) has the same effect as sb.insert(sb.length(), x) .

Every string builder has a capacity. As long as the length of the character sequence contained in the string builder does not exceed the capacity, it is not necessary to allocate a new internal buffer. If the internal buffer overflows, it is automatically made larger.

Instances of StringBuilder are not safe for use by multiple threads. If such synchronization is required then it is recommended that StringBuffer be used.

Unless otherwise noted, passing a null argument to a constructor or method in this class will cause a NullPointerException to be thrown.

Источник

Append a byte to a string

How should I order python string to work byte string? would be fine too: You should think of characters as characters rather than either bytes or integer values.

Appending a byte to String in java using escape sequence

I wish to append a byte i.e. 16 = 0x10 to a String, using escape sequence to do it in single line of code:

String appendedString = new String('\16'+"String"); 

This results in a hex representation of appendedString = 0x0E,0x74,0x72,0x69,0x6E,0x67

String appendedString = new String('\2'+"String"); 

works fine resulting in a hex representation of appendedString = 0x02,0x74,0x72,0x69,0x6E,0x67

String appendedString = new String('\10'+"String"); 

results in a hex representation of appendedString = 0x08,0x74,0x72,0x69,0x6E,0x67

Someone may kindly explain this and suggest a solution. Thanks.

\10 is in octal which is why you’re getting U+0008.

I don’t believe there are any escape formats which use decimal; I’d suggest using the \uxxxx format, or specific escape sequences for supported characters ( \r , \n etc). So for the second case you could use \u000a — or just use \n in this case. For the first, you’d use \u0010 .

See section 3.10.6 of the JLS for more details about escape sequences.

I’d also strongly recommend that you stop thinking of these as bytes — they’re characters (or UTF-16 code units, if you want to be really precise).

The problem is that you are using an octal escape. The Java Language Specification, Section 3.10.6, defines escapes, including octal escapes.

OctalEscape: \ OctalDigit \ OctalDigit OctalDigit \ ZeroToThree OctalDigit OctalDigit

So, \16 is the character 14 in decimal, or 0x0E in hexadecimal.

The character \2 remains 2 in decimal and hexadecimal.

The character \10 is 8 in decimal, or 0x08 in hexadecimal.

To use hexadecimal escapes, use a Unicode escape, defined in JLS Section 3.3:

\ UnicodeMarker HexDigit HexDigit HexDigit HexDigit 

such as \u0016 , \u0002 , and \u0010 .

Appending a byte to String in java using escape sequence, I wish to append a byte i.e. 16 = 0x10 to a String, using escape sequence to do it in single line of code: String appendedString = new String …

Append bytes to string in python

I have bytes array as str and want to send it (if I look at it through a debugger, it shows me that File.body is str ). For that reason I have to create message to send.

request_text += '\n'.join([ '', '--%s' % boundary_id, attachment_headers, File.body, ]) 

But at only it tries to join file body, I receive exception:

UnicodeDecodeError: 'ascii' codec can't decode byte 0xff in position 0: ordinal not in range(128) 

Still, in example where I took it, it was implemented this way. How should I order python string to work byte string? Do I should decode it somehow? But how, if that is not text, but just bytes.

You are probably getting the error as your string has non-ascii characters. The following is an example on how to encode/decode a string containing non-ascii characters

1) convert the string to unicode

string=»helloé» u=unicode(string, ‘utf-8’)

2) Encode the string to utf-8 before sending it on the network

3) Decode it from utf-8 to unicode on the other side

C++ How to append a string to BYTE array?, @StevenHansen Thank for your comment. I know how to calling a C++ function from C#. I have a byte array from C# and pass to C++ function. For …

Append bytes to string in java

I have to deal with ascii structured file, I need to put these two constant bytes to the end of every line so that I can respect the file structure that was gave me:

private final static int ENDRECORD = 0x0d; private final static int ENDLINE = 0x0a; 

I don’t know if it’s the classic «\n», is there a way I can put these two variables at the end of a string? Like:

String line = line + ENDRECORD + ENDLINE; //I now this is wrong

System.out.println((int) '\r'); System.out.println((int) '\n'); 

which is 0x0d and 0x0a , respectively. Use char s:

private final static char ENDRECORD = '\r'; private final static char ENDLINE = '\n'; 

String line = line + ENDRECORD + ENDLINE; 

Additionally, you can use StringBuilder for efficiency instead of concatenation. It’s not necessary to get this to work, but it’s standard to use it for building strings instead of concatenation with + .

Just change your constants to be strings instead:

private final static String ENDRECORD = "\r"; private final static String ENDLINE = "\n"; 

Then your existing concatenation should be fine.

private final static char ENDRECORD = '\r'; // Or (char) 0x0d private final static char ENDLINE = '\n'; // Or (char) 0x0a 

You should think of characters as characters rather than either bytes or integer values. It’ll make your text handling a lot simpler.

You will want the values to be characters instead of integers.

private static final char ENDRECORD = (char)0x0d; private static final char ENDLINE = (char)0x0a; . line = line + ENDRECORD + ENDLINE; 

I’m going to assume you have more than a single record, so a better way would be to create a loop for each record and use a StringBuilder :

StringBuilder buffer = new StringBuilder(4096); for (final String record: records)

If all you’re going to do the the record is to output it, then there’s no need to put it in a StringBuilder ; just write it to your Stream or Writer:

OutputStream out = new FileOutputStream("records.dat"); for (final String record: records)

You have to change the datatype to char .

String myFullLine = line + (char)ENDRECORD + (char)ENDLINE; 

If your are planning on doing this for more than one line I recommed using a StringBuilder .

Python — Convert bytes to a string, String = Bytes.decode(«utf-8»).replace(«\r\n», «\n») Why? Try this with a multiline Input.txt: Please edit your answer to add an explanation, and give an …

Double appending \\ in a byte string python

I’m trying to convert a hex string \x11\x22\x33\x44\x55 to a byte string where it should become b’\x11\22\33\44\55′ . I’m aware of byte.fromhex() however, this causes \x22 to be output as » which changes my output to a false positive.

I’ve tried converting a string \x11\x22\x33\x44\x55 to byte string by using str.encode(bytestring) however, this causes the string to become b’\\x11\\x22\\x33\\x44\\x55′ . Again, giving a false positive.

Is it possible to transfer the hex string into bytes so it just displays as b’\x11\x22\x33\x44\x55′ ?

cause \x22 to be output as » which changes my output to a false positive.

This pertains only to display consider that

StringBuilder append byte without formatting, However the above is the code I am having issues with, specifically I have researched and found that the string builder .Append(byte) actually does a …

Источник

How to append a byte to a string in Java?

The advantage of using SQL statements that take parameters is that you can use the same statement and supply it with different values each time you execute it. For example, if you want to avoid sql injection attacks. See the examples in Using Prepared Statements from The Java Tutorials .

JDBC — How to insert a string value

For various reasons, it is better to use java.sql.PreparedStatement . to execute statements with parameters. For example, if you want to avoid sql injection attacks.

See the examples in Using Prepared Statements from The Java Tutorials .

The advantage of using SQL statements that take parameters is that you can use the same statement and supply it with different values each time you execute it.

PreparedStatement pstmt = conn.prepareStatement( "UPDATE EMPLOYEES SET FIRST_NAME= ? WHERE "user1080390"); // set parameter 1 (FIRST_NAME) pstmt.setInt(2, 101); // set parameter 2 (ID) int rows = pstmt.executeUpdate(); // "rows" save the affected rows 

String sql = «Insert INTO users (ID, firstName, address) VALUES (‘124’,'»+firstName()+»‘,’123’)»;

To prevent sql injections, you need to escape the string before using in a query or try the prepared statements.

String firstName ="sample"; String sql = "Insert INTO users (ID, firstName, address) VALUES ('124',"+firstName+",'123')"; 

Insert a String into another String in Java, Using String.substring () method Approach: Get the Strings and the index. Create a new String Insert the substring from 0 to the specified (index + 1) …

How to append a byte to a string in Java?

If you want to concatenate the actual value of a byte to a String use the Byte wrapper and its toString() method, like this:

String someString = "STRING"; byte someByte = 0x10; someString += Byte.toString(someByte); 

If you want to have the String representation of the byte as ascii char then try this:

public static void main(String[] args) < String a = "bla"; byte x = 0x21; // Ascii code for '!' a += (char)x; System.out.println(a); // Will print out 'bla!' >

If you want to convert the byte value into it’s hex representation as String then take a look at Integer.toHexString

If you just want to extend a String literal, then use this one:

System.out.println("Hello World\u0010"); 

String s1 = "Hello World"; String s2 = s1 + '\u0010'; 

And no — character are not bytes and vice versa. But here the approximation is close enough 🙂

Inserting a Java string in another string without, The compiler will generate the same bytecode for new StringBuilder ().append («hello»).append (value1).toString () as for «hello» + value1; You can …

Adding values in List dynamically

It’s not adding a null value (it’s not a null reference) — but it’s not adding a useful value:

In what way were you expecting that to be useful? Shouldn’t you be adding a useful string value instead of just a new empty string?

You just add a new empty string. Switch it to something else, e.g:

periods.add(new String("hey there!")); 

Pass some String to the function addList, else it will keep on adding empty Strings to the list. When you write something like, periods.add(new String(«Kanika»)) , and its added in List as many times as you press add button, that means your function is working fine. But unless and until you will pass something to it, it will not insert anything meaningful.

Java: How to add a string value in a custom ArrayList, Also using the List interface is a better practice. ArrayList aList = new ArrayList (); List aList = new …

Add string values into Java

txtsaat.setText(getString(R.string.baslat)); 

If the above one gives you an error here is Method 2:

this.getResources().getString(R.string.baslat); 

where ‘this’ is your Activity Context.

You can get a string from strings.xml to java class in this way.

txtsaat.setText(getString(R.string.app_name)); 

If in case getString() shows an error try this way by calling context.

txtsaat.setText(getApplicationContext().getString(R.string.app_name)); 

applicationContext.getString(R.string.app_name) 

How to add Dynamic String value to String array in java, 2 Answers. In this every time the dynamically changing value of label will be added into the container. List container = new ArrayList …

Источник