搜索和打印使用Java IO

Question

我必须设计成用作地址簿中的程序中的特定行。它有3种方法：一种允许添加新联系人，一种可以打印出图书中的所有联系人，另一种允许您按姓氏搜索联系人，并只打印联系人信息。我有前两个完美的工作，但最后一个总是打印列表中的所有联系人，我不知道为什么。

问题出在search（）方法中。我添加了很多评论，这样你们就可以告诉程序中发生了什么。

警告：代码传入的墙。

/** 
*/ 
import java.util.*; 
import java.io.*; 

public class ContactList 
{ 
    /** 
    Contact list file name 
    */ 
    private String filename; 

    /** 
    ContactList constructor accepts a String parameter 
    */ 
    public ContactList(String inFileName) 
    { 
     filename = inFileName; 
    } 

    /** 
     3) add a new record to the file. Open the file for writing in append mode. 
     a) prompt the user to enter data for each field in the record. Each field is a String. 
      The last name is required. If the last name is the empty string(""), return to the menu. 
     b) when the user has completed entering data(i.e., all the fields have been prompted), re-display the user choices 
     c) do not overwrite existing data 
    */ 
    public void new_record() 
    {  
     /* 
     Prompt for data: 
     Last name 
     First name 
     Phone 

    */ 
     //Craete a scanner object 
     Scanner in = new Scanner(System.in); 


     //prompt for the last name 
     System.out.println("Please Enter Contact's Last Name: "); 

     //input the last name 
     String lastName = in.nextLine(); 

     //the Last_name must not be empty 
     if(lastName.length() > 0) 
     { 
      //get the first name and the phone 
      System.out.println("Please Enter Contact's First Name: "); 
      String firstName = in.nextLine(); 

      System.out.println("Please Enter Contact's Phone Number [xxx-xxx-xxxx]: "); 
      String phone = in.nextLine(); 

      //create the output string 
      String contact = lastName + ","; 
      contact = contact + firstName + ","; 
      contact = contact + phone; 

      System.out.println(""); 
      System.out.println("Last Name: " + lastName); 
      System.out.println("First Name: " + firstName); 
      System.out.println("Phone: " + phone); 
      System.out.println("");   

      //try to open the file for writing - append the data 
      FileWriter fw = null; 
      BufferedWriter bw = null;   
      try 
      {    
       fw = new FileWriter(filename,true); 
       bw = new BufferedWriter(fw); 
      } 
      catch(IOException ioe) 
      { 
       System.out.println("new_record: Exception opening the file for writing"); 
      } 
      //try to wrtie the data 
      try 
      { 
       bw.write(contact); 
       bw.newLine();  
      } 
      catch(IOException ioe) 
      { 
       System.out.println("new_record: Exception writing to the file"); 
      } 
      //try to close the file 
      try 
      { 
       bw.flush(); 
       bw.close(); 
       fw.close(); 
      } 
      catch(IOException ioe) 
      { 
       System.out.println("new_record: Exception closing the file"); 
      } 

     }//end of test of Last_name 

    }//end of new_record 

    /** 
    2) display all last names and first names in the file. 
     Open the file for reading, read each record and 
     display the field values. 
     a) display all the lastName, firstName paired fields in the file; 
     display with the format lastName, firstName 
     b) when all records have been displayed, display the record count - the record count is the number of records read and should equal the number of records in the file 
     c) after all the records and the count have been displayed, display the user choices 

    */ 
    public void display_names() 
    { 
     FileReader fn = null; 
     BufferedReader br = null; 

     //try to open the file for reading 
     try 
     { 
      fn = new FileReader(filename); 
      br = new BufferedReader(fn); 
     } 
     catch(IOException ioe) 
     { 
      System.out.println("display_names: Exception opening the file"); 
     } 

     /* 
     try to read each record and display the field values. 
     a) display all the lastName, firstName paired fields in the file; 
      display with the format lastName, firstName 
      count each record that is read 
     */ 
     int counter = 0; //record counter 
     try 
     { 
      //read the first record 
      String line = br.readLine(); 
      //while the record is not null, display the record, count the record 
      while(line != null) 
      { 
       System.out.println(line); 
       counter++; 
       line = br.readLine(); 
      }  
     } 
     catch(IOException ioe) 
     { 
      System.out.println("display_names: Exception reading the file"); 
     } 

     //try to close the file 
     try 
     { 
      br.close(); 
      fn.close();  
     } 
     catch(IOException ioe) 
     { 
      System.out.println("display_names: Exception closing the file"); 
     } 
     //display a count of the records read 
     System.out.println(""); 
     System.out.println("Records Displayed: " + counter); 
     System.out.println(""); 
    }//end of display_names 

    /** 
     1) search an address file for a particular last name 
     and then display the Last name, the first name, and 
     the phone for each match 
     2) display the count of records which match the last name 

    */ 
    public void search(String findMe) 
    { 
     FileReader fn = null; 
     BufferedReader br = null; 

     //try to open the file for reading 
     try 
     { 
      fn = new FileReader(filename); 
      br = new BufferedReader(fn); 
     } 
     catch(IOException ioe) 
     { 
      System.out.println("search: Exception opening the file"); 
     } 

     //try to read each record 
     int counter = 0; 
     try 
     { 
      String line = br.readLine(); 
      while(line != null) 
      { 
       String [] fields = line.split(","); 
       if(findMe.equals(fields[0])); 
       { 
        System.out.println(line); 
        System.out.println(""); 
        counter++; 
       } 
       line = br.readLine(); 
      }  
     } 
     catch(IOException ioe) 
     { 
      System.out.println("Search: Exception Reading the File."); 
     } 

     //Try to close the file 
     try 
     { 
      br.close(); 
      fn.close();  
     }     
     catch(IOException ioe) 
     { 
      System.out.println("search: Exception closing the file"); 
     } 
     //dislay a count of the records found 
     System.out.println("Records Searched: " + counter); 
     System.out.println("");  
    }//end of search 
}//end of class 

这里是非常简单的测试类，与它去：

import java.util.*; 
public class TestContactList 
{ 
    public static void main(String [] args) 
    { 
     final int ONE = 1; 
     final int TWO = 2; 
     final int THREE = 3; 
     final int FOUR = 4; 
     final int FIVE = 5; 

     Scanner scan = new Scanner(System.in); 
     while(true) 
     { 
      System.out.println("1) Search the file for a last name "); 
      System.out.println("2) Display all last & first names in file"); 
      System.out.println("3) Add a new record to the file "); 
      System.out.println("4) End the program "); 
      System.out.print("Please choose 1 - 4: "); 
      int choice = scan.nextInt(); 
      scan.nextLine(); 

      /* 
      Create a new ContactList object with the name of the 
      contact list file. 
      */ 
      ContactList cl = new ContactList("MyAddressBook.txt"); 

      if(choice == ONE) 
      { 
       System.out.print("Enter name to find: "); 
       String findMe = scan.nextLine(); 
       cl.search(findMe); 
      } 

      if(choice == TWO) 
      { 
       // then call display names 
       cl.display_names(); 
      } 

      if(choice == THREE) 
      { 
       // then call new record 
       cl.new_record(); 
      } 

      if(choice == FOUR) { System.exit(0); } 
     } 
    } 
} 

Answer 1

我发现的错误。你必须拿走“;”

if(findMe.equals(fields[0])); <---oops