Java中的 StringWriter append(CharSequence, int, int) 方法及示例

Java中StringWriter类的append(CharSequence, int, int)方法用于将指定charSequence的指定部分追加到writer上。这个 charSequence 被当作一个参数。要写入的起始索引和结束索引也作为参数。

句法：

public void append(CharSequence charSequence, int startingIndex, int endingIndex)

参数：此方法接受三个强制参数：

• charSequence是要写入 Stream 的 charSequence。
• 起始索引，它是从中获取字符部分的起始索引。
• endingIndex是要写入 writer 的结束索引。

返回值：此方法不返回任何值。

下面的程序说明了 append(CharSequence, int, int) 方法的工作：

方案一：

// Java program to demonstrate
// StringWriter append(CharSequence, int, int) method
  
import java.io.*;
  
class GFG {
    public static void main(String[] args)
    {
  
        try {
  
            // Create a StringWriter instance
            StringWriter writer
                = new StringWriter();
  
            // Get the charSequence
            // to be written in the writer
            CharSequence charSequence = "GeeksForGeeks";
  
            // Get the starting index
            int startingIndex = 0;
  
            // Get the length of char
            int endingIndex = 5;
  
            // Write the portion of the charSequence
            // to this writer using append() method
            // This will put the charSequence in the writer
            // till it is printed on the console
            writer.append(charSequence,
                          startingIndex,
                          endingIndex);
  
            System.out.println(writer.toString());
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

输出：

Geeks

方案二：

// Java program to demonstrate
// StringWriter append(CharSequence, int, int) method
  
import java.io.*;
  
class GFG {
    public static void main(String[] args)
    {
  
        try {
  
            // Create a StringWriter instance
            StringWriter writer
                = new StringWriter();
  
            // Get the charSequence
            // to be written in the writer
            CharSequence charSequence = "GFG";
  
            // Get the starting index
            int startingIndex = 2;
  
            // Get the length of char
            int endingIndex = 3;
  
            // Write the portion of the charSequence
            // to this writer using append() method
            // This will put the charSequence in the writer
            // till it is printed on the console
            writer.append(charSequence,
                          startingIndex,
                          endingIndex);
  
            System.out.println(writer.toString());
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

输出：

G