Java StringBuffer 和 StringBuilder 类

When modifying strings, you need to use the StringBuffer and StringBuilder classes.

Unlike the String class, objects of the StringBuffer and StringBuilder classes can be modified multiple times without creating new unused objects.

The StringBuilder class was proposed in Java 5. The biggest difference between it and StringBuffer is that StringBuilder The method is not thread-safe (thread safety means that when multi-threads access, a locking mechanism is used. When a thread accesses certain data of this class, it is protected and other threads cannot access it until the thread finishes reading. Other threads It can be used. There will be no data inconsistency or data pollution. Thread unsafe means that it does not provide data access protection, and it is possible that multiple threads change the data successively and the resulting data is dirty data).

Since StringBuilder has a speed advantage compared to StringBuffer, it is recommended to use the StringBuilder class in most cases. However, when the application requires thread safety, the StringBuffer class must be used.

Example

 public class Test{ public static void main(String args[]){ StringBuffer sBuffer = new StringBuffer(" test"); sBuffer.append(" String Buffer"); System.out.println(sBuffer); } }

The compilation and running results of the above example are as follows:

 test String Buffer

StringBuffer method

The following are the main methods supported by the StringBuffer class:

The methods in the following list are similar to those of the String class: