StringBuffer的解读（二）

StringBuffer默认容量大小是16个字符。

• StringBuffer后面append NULL的测试，代码如下：

public class Test { public static void main(String[] args) { StringBuffer sb = new StringBuffer("the"); System.out.println("sb is: " + sb);; String str = null; sb.append(str); System.out.println("sb is: " + sb);; } }

• StringBuffer后面append字符串+原先字符数组<容量的测试，代码如下：

public class Test { public static void main(String[] args) { StringBuffer sb = new StringBuffer("the"); System.out.println("sb.length: " + sb.length()); System.out.println("sb.capacity: " + sb.capacity()); sb.append(" redpig"); System.out.println("sb.length: " + sb.length()); System.out.println("sb.capacity: " + sb.capacity()); } }

• StringBuffer后面append字符串+原先字符数组>容量，且<容量x2+2的测试，代码如下：

public class Test { public static void main(String[] args) { StringBuffer sb = new StringBuffer("the"); System.out.println("sb.length: " + sb.length()); System.out.println("sb.capacity: " + sb.capacity()); sb.append(" redpig is writting java programs"); System.out.println("sb.length: " + sb.length()); System.out.println("sb.capacity: " + sb.capacity()); } }

• StringBuffer后面append字符串+原先字符数组>容量x2+2的测试，代码如下：

public class Test { public static void main(String[] args) { StringBuffer sb = new StringBuffer("the");//original length is 3 System.out.println("sb.length: " + sb.length()); System.out.println("sb.capacity: " + sb.capacity()); sb.append(" redpig is writting java programs for fun");//string's length is 33 System.out.println("sb.length: " + sb.length()); System.out.println("sb.capacity: " + sb.capacity()); } }