Java StringBuffer delete()方法及示例

java.lang.StringBuffer.delete()是Java中的一个内置方法，用于删除或删除该序列的子串中的字符。该子串从指定的索引起点开始，延伸到索引终点的字符。

语法:

public StringBuffer delete(int start_point, int end_point)

参数：该方法接受两个整数类型的参数：

start_point – 这是指起始索引，包含在计数中。

end_point – 这是指结束索引，不包含在计数中。

返回值：该方法在删除参数中提到的范围所形成的子串后返回字符串。

异常情况。如果start_point是负数，大于length()，或者大于end_point，会发生StringIndexOutOfBoundsException。

例子 :
输入: String = “Apple”
start_point = 2
end_point = 4

输出:Ape

输入: String = “GeeksforGeeks”
start_point = 2
end_point = 7

输出:GerGeeks

下面的程序说明了java.lang.StringBuffer.delete()方法：
程序1：

// Java program to illustrate the
// java.lang.StringBuffer.delete()
import java.lang.*;
  
public class geeks {
  
    public static void main(String[] args)
    {
  
        StringBuffer sbf = new StringBuffer("Geeksforgeeks");
        System.out.println("string buffer = " + sbf);
  
        // Deleting characters from index 2 to 7
        sbf.delete(6, 8);
        System.out.println("After deletion string buffer is = " + sbf);
    }
}

输出:

string buffer = Geeksforgeeks
After deletion string buffer is = Geeksfgeeks

程序2：

// Java program to illustrate the
// java.lang.StringBuffer.delete()
import java.lang.*;
  
public class geeks {
  
    public static void main(String[] args)
    {
  
        StringBuffer sbf = new StringBuffer("Welcome to Geeksforgeeks");
        System.out.println("string buffer = " + sbf);
  
        // deleting characters from index 5 to index 9
        sbf.delete(5, 9);
        System.out.println("After deletion string buffer is = " + sbf);
    }
}

输出:

string buffer = Welcome to Geeksforgeeks
After deletion string buffer is = Welcoo Geeksforgeeks

方案3： 这里的指数是负的。

// Java program to illustrate the
// java.lang.StringBuffer.delete()
import java.lang.*;
  
public class geeks {
  
    public static void main(String[] args)
    {
  
        StringBuffer sbf = new StringBuffer("Welcome to Geeksforgeeks");
        System.out.println("string buffer = " + sbf);
  
        sbf.delete(-5, 9);
        System.out.println("After deletion string buffer is = " + sbf);
    }
}

输出:

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: 
                                         String index out of range: -5
    at java.lang.AbstractStringBuilder.delete(AbstractStringBuilder.java:756)
    at java.lang.StringBuffer.delete(StringBuffer.java:430)
    at geeks.main(geeks.java:13)

程序4： 这里的索引不存在。

// Java program to illustrate the
// java.lang.StringBuffer.delete()
import java.lang.*;
  
public class geeks {
  
    public static void main(String[] args)
    {
  
        StringBuffer sbf = new StringBuffer("Welcome to Geeksforgeeks");
        System.out.println("string buffer = " + sbf);
  
        sbf.delete(99, 109);
        System.out.println("After deletion string buffer is = " + sbf);
    }
}

输出:

Exception in thread "main" java.lang.StringIndexOutOfBoundsException
    at java.lang.AbstractStringBuilder.delete(AbstractStringBuilder.java:760)
    at java.lang.StringBuffer.delete(StringBuffer.java:430)
    at geeks.main(geeks.java:13)