Java字符串类之间的转换

在Java中，有三个主要的字符串类：String、StringBuffer和StringBuilder。这些类之间可以相互转换，具体方法如下：

1. String转换为StringBuffer或StringBuilder

String str = "Hello World";
StringBuffer sb = new StringBuffer(str);
StringBuilder sbd = new StringBuilder(str);

2. StringBuffer或StringBuilder转换为String

StringBuffer sb = new StringBuffer("Hello World");
StringBuilder sbd = new StringBuilder("Hello World");
String str1 = sb.toString();
String str2 = sbd.toString();

3. String转换为字符数组

String str = "Hello World";
char[] charArray = str.toCharArray();

4. 字符数组转换为String

char[] charArray = {'H', 'e', 'l', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd'};
String str = new String(charArray);

5. 字符数组转换为StringBuffer或StringBuilder

char[] charArray = {'H', 'e', 'l', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd'};
StringBuffer sb = new StringBuffer(charArray);
StringBuilder sbd = new StringBuilder(charArray);

6. StringBuffer或StringBuilder转换为字符数组

StringBuffer sb = new StringBuffer("Hello World");
StringBuilder sbd = new StringBuilder("Hello World");
char[] charArray1 = new char[sb.length()];
char[] charArray2 = new char[sbd.length()];
sb.getChars(0, sb.length(), charArray1, 0);
sbd.getChars(0, sbd.length(), charArray2, 0);