StringBuilder的字符操作技巧

1. 使用append()方法来添加字符或字符串到StringBuilder对象中：

StringBuilder sb = new StringBuilder();
sb.append("Hello");
sb.append(" ");
sb.append("World");
System.out.println(sb.toString()); // Output: Hello World

2. 使用insert()方法来在指定位置插入字符或字符串到StringBuilder对象中：

StringBuilder sb = new StringBuilder("Hello World");
sb.insert(5, ","); // Insert a comma at index 5
System.out.println(sb.toString()); // Output: Hello, World

3. 使用delete()方法来删除指定范围内的字符或字符串：

StringBuilder sb = new StringBuilder("Hello, World");
sb.delete(5, 7); // Delete characters from index 5 to 7
System.out.println(sb.toString()); // Output: Hello World

4. 使用replace()方法来替换指定范围内的字符或字符串：

StringBuilder sb = new StringBuilder("Hello, World");
sb.replace(7, 12, "Java"); // Replace characters from index 7 to 12 with "Java"
System.out.println(sb.toString()); // Output: Hello, Java

5. 使用reverse()方法来反转StringBuilder对象中的字符序列：

StringBuilder sb = new StringBuilder("Hello");
sb.reverse();
System.out.println(sb.toString()); // Output: olleH