Question

我几乎就在那里，但是我在删除异常捕获时遇到错误。第二行到最后一行代码。还有什么方法可以只选择阵列上的特定点打印到文本文件？感谢

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

public class Project_Space

{
  public static void main(String[] args)
  {
// 2D Array of Passengers and Pilots objects- the Passengers class is in the Person.java file
    Person[][] Members ;

  int num_flights= 6;  //create the "x" bound/size of the array
  int num_passengers= 9;     //create the "y" bound/size of the array

  Members = new Person[num_flights][num_passengers];

  //The Members array at index 0 is the first company
  Members[0][0] = new Person.Flight(1);  //This spot in the array is for the Company number in the first spot. Everything else are place holders for data that doesn't pertain to the company
  Members[0][1] = new Person.Pilots(1,"1877963200","Amadeus","Durrutti","Buckminster Cornwallis","1288211435", 11);  //This spot in the array is for the first team member of company #1
  Members[0][2] = new Person.Pilots(2,"6054350085","Sirius","Sassafrass","Ali Bababa","1776812631", 9);
  Members[0][3] = new Person.Passengers(1,"7065253333","Amy","Hartman","Betty Sue","7708889999", 3, 50000,"0554055405540554");
  Members[0][4] = new Person.Passengers(2,"7545251337","Amanda","Zion","Beatrice Twix","7448656577", 4, 2000,"0554055405541111");
  Members[0][5] = new Person.Passengers(3,"8904448899","Janet","Graves","Neal Wade","4445556666", 5, 3000, "9031029266161432");
  Members[0][6] = new Person.Passengers(4,"8902234567","Kristen","Pickering","Christopher Soto","5685461208", 6, 51500, "0985028135114275");
  Members[0][7] = new Person.Passengers(5,"5000893778","Julianna","Estrada","Jill Hansen","2770779833", 7, 0, "0213595590286251");
  Members[0][8] = new Person.Passengers(6,"2080670437","Regena","Mckenzie","Vicki Cook","6224215759", 8, 250, "8204699533830238");

...

  Arrays.deepToString(Members);
 PrintWriter writer;
try
{
  writer = new PrintWriter("flightnames.txt");
for (int i = 0; i<Members.length; i++){
for(int j = 0; j<Members.length; j++){
writer.print(Members[i][j] + ",");
}writer.println();
}} 
catch (FileNotFoundException e){
System.out.println("Error: " + e.getMessage()); 
} 
finally{if (writer!=null) 
  writer.close(); 
catch (Exception e) 
{System.out.println("Could not close writer");}
}
}
}

Answer 1

移动你的finally块，它应该正确编译。为了将来使用IDE并使用格式化，它会更快地向您显示您的错误：）

Arrays.deepToString(Members);
PrintWriter writer;
try {
  writer = new PrintWriter("flightnames.txt");
  for (int i = 0; i < Members.length; i++) {
    for (int j = 0; j < Members.length; j++) {
      writer.print(Members[i][j] + ",");
    }
    writer.println();
  }
} catch (FileNotFoundException ex) {
  System.out.println("Error: " + ex.getMessage());
} catch(Exception ex){
    System.out.println("Could not close writer"+ ex.getMessage());
} finally {
  if (writer != null) {
    try{
      writer.close();
    } catch(IOException ex) {
      System.out.print("Error while closing file: "+ ex.getMessage())
    }
  }
}

Answer 2

看起来你真正想要的是这个：

...
finally {
    if (writer!=null) {
       try {
          writer.close(); 
       } catch (Exception e) {
          System.out.println("Could not close writer");
       }
    }
 }

也就是说，在您的try电话周围有一个专门的catch / writer.close()来通过关闭writer来报告错误。

此外，您需要将作者初始化为null。如果if (writer!=null)可能永远不会被分配，则您无法writer（或实际上writer的任何其他内容）。

因此，请将您的writer声明更改为：

PrintWriter writer = null;

将2D阵列上的特定点打印到文本文件？ Java的

2 个答案: