即使我导入了 java.lang.*，deleteCharAt() 方法的“找不到符号”错误

Question

我是一个非常初级的JAVA编码员，这个问题可能真的很幼稚，但正如问题所述，我的代码不断给我错误，因为我无法找到deleteCharAt(). 我真的很感激一些见解！这是我的代码

    package hw5;
    import java.util.*;
    import java.lang.*; 

    public class Business {
      String businessID;
      String businessName;
      String businessAddress;
      String reviews;
      int reviewCharCount;


      // Constructor for the Business Class
      public Business (String s) {
        String[] temp = s.split(", "); // splits the string by a comma and space
        businessID = temp[0]; // stores first index into business ID
        businessID.deleteCharAt(0); // delete the { 
        businessName = temp[1]; // stores 2nd index into businessName 
        businessAddress = temp[2]; // stores 3rd index into businessName 
        reviews = temp [3]; // tores 4th index into businessName
        reviews.deleteCharAt(reviews.length()-1); // delete the last }
        reviewCharCount = reviews.length(); // input character # into reviewCharCount
      }

      public List reviewList() {
        String[] temp = this.reviews.split(" "); // make reviews into an array
        List<String> list = Arrays.asList(temp); // make array into a list 
        Iterator<String> itr = list.iterator(); // initializes iterator for list
        while (itr.hasNext()) { // iterates over the whole list 
          String uniqueWord = itr.next(); // store next element into string
          // if the string equals a nonimportant word 
          if (uniqueWord.equals("a") || uniqueWord.equals("the") || uniqueWord.equals("is") || uniqueWord.equals("and")) { 
            list.remove(uniqueWord); // remove the word
          }
        }
        return list; // returns list 
      }

      public String toString() {
        return "-------------------------------------------------------------------------------\n"
              + "Business ID: " + businessID + "\n"
              + "Business Name: " + businessName + "\n"
              + "Business Address: " + businessAddress + "\n"
              //+ "Reviews: " + reviews + "\n"
              + "Character Count: " + reviewCharCount;
      }
    }

Answer 1

因为没有String.deleteCharAt(int)方法。这里是一个StringBuilder.deleteCharAt(int)方法。改变

String businessID;

到

StringBuilder businessID;

和

businessID = temp[0];

到

businessID = new StringBuilder(temp[0]);

并且在您想使用的其他任何地方都一样deleteCharAt(int)。一旦这样做，如果需要的话，你可以打电话toString()的StringBuilder，并得到一个不可改变的 String。