Java string concatenation method and usage scenarios

Java string concatenation method and usage scenarios

1. Using +the operator

code example

String str1 = "Hello, ";
String str2 = "World!";
String result = str1 + str2;

scenes to be used

• Good for small scale string concatenation.
• When there are fewer splicing operations, the readability is good and the code is concise.

2. Using StringBuilderthe class

code example

StringBuilder builder = new StringBuilder();
builder.append("Hello, ");
builder.append("World!");
String result = builder.toString();

scenes to be used

• Suitable for mass concatenation of strings in a single-threaded environment.
• Can improve performance when strings need to be modified frequently.

3. Using StringBufferthe class

code example

StringBuffer buffer = new StringBuffer();
buffer.append("Hello, ");
buffer.append("World!");
String result = buffer.toString();

scenes to be used

• Suitable for concatenating strings in large numbers in a multi-threaded environment.
• Used when thread safety is required.

4. String.concatHow to use

code example

String str1 = "Hello, ";
String result = str1.concat("World!");

scenes to be used

• When you need to append one string to the end of another.
• Useful when splicing operations are explicitly indicated.

5. String.formatHow to use

code example

String result = String.format("%s%s", "Hello, ", "World!");

scenes to be used

• When formatted string concatenation is required.
• It is suitable for occasions that need to insert variables or use specific formats.