java 字符串无法转换为 StringBuffer
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String cannot be converted to StringBuffer
提问by CodeCodeCode
I am making a playfair cipher and I encountered an error that String cannot be converted to StringBuffer. How can I make my program work? Or how can I convert StringBuffer to String without compromising the code?
我正在制作一个 playfair 密码，但遇到一个错误，即 String 无法转换为 StringBuffer。我怎样才能使我的程序工作？或者如何在不影响代码的情况下将 StringBuffer 转换为 String？
public static StringBuffer addFiller (StringBuffer input)
{
for( int x = 0; x < input.length() - 1; x++)
{
if(input.substring(x+1, 1).equals(input.substring(x, 1)))
{
input = input.insert(x+1, "Q");
}
if("Q".equals(input.substring(x, 1)) && "Q".equals(input.substring(x+1, 1)))
{
input = input.insert(x+1, "Z");
}
}
return input;
}
public static String modifyPlaintext(String keyword)
{
keyword = keyword.toUpperCase();
keyword = keyword.trim();
keyword = keyword.replace(" ","");
//StringBuffer.toString(addFiller);
keyword = addFiller(keyword); // error starts here and it says that keyword = java.lang.String "ALLISKNOWNFLYATONCE" even though I didn't initialize it. What does it mean?
if (keyword.length() % 2 != 0)
{
keyword += "Q";
}
keyword = insertSpaceInSpecificNumber(2, keyword, ' ');
return keyword;
}
回答by Kaustubh Khare
1) Create StringBufferobject and pass it to addFilter().
1) 创建StringBuffer对象并将其传递给addFilter().
2) Convert StringBufferobject return by addFilter()into String by toString().
2) 将StringBuffer对象 return byaddFilter()转换为 String by toString()。
keyword = addFilter(new StringBuffer(keyword)).toString();
回答by Vikrant Kashyap
Stringis final and immutable too
String也是最终的和不可变的
so , This class cannot be extended or inherited by any other class. So, There is no IS-ARelationship between these two classes.
So,
所以，这个类不能被任何其他类扩展或继承。所以，IS-A这两个类之间没有关系。所以，
String never be converted or referenced to any other Class except
java.lang.Objectdirectly .
除了
java.lang.Object直接之外，字符串永远不会被转换或引用到任何其他类。
but StringBufferprovides a Constructor through which you can convert a Stringinto a StringBufferObject.
但StringBuffer提供了一个构造函数，通过它您可以将 a 转换String为一个StringBuffer对象。
public java.lang.StringBuffer(java.lang.String); //pass string as an argument. StringBuffer object will you get.
so here you should try this code
所以在这里你应该试试这个代码
addFilter(new StringBuffer(keyword)).toString();//try this code
Thanks.
谢谢。
