Java GUI-读取文本文件，该文本文件的每一行都是其自己的字符串

Question

Ok. So I am working on a program that gets information that has been put into textfields in a gui and puts that information into a text file and the name of the file is the name of the animal and name of the owners last name.

//that part is done.

Then able to search for the file using the name of the animal and the owners last name, and being able to have the information be put into separate text fields. That look like the page where you first put down the information. Then being able to save the information changed to the same text file.

Now my question is how do I get the information from a text file that has different lines and then put each line in its own String.

Here is the part of the program that reads the text file

`import java.io.IOException;
import java.io.FileReader;
import java.io.BufferedReader;

public class ReadFile {

  private String path;


  public ReadFile(String file_path) {
    path = file_path;
  }

  public String[] OpenFile() throws IOException {

    FileReader fr = new FileReader (path);
    BufferedReader textReader = new BufferedReader(fr);

    int numberOfLines = 20; 
    String[] textData = new String[numberOfLines];

    int i;

    for (i=0; i < numberOfLines; i++) {
      textData[i] = textReader.readLine();

  }
    textReader.close();
    return textData;
} 
   int readLines() throws IOException {
    FileReader file_to_read = new FileReader(path);
    BufferedReader bf = new BufferedReader(file_to_read);

    String aLine;
    int numberOfLines = 0;

    while (( aLine = bf.readLine()) != null) {
      numberOfLines++;
    }
           bf.close();

           return numberOfLines;
           }
}
`
// Here is where I am using this code

    `JButton b7 = new JButton("Done");
         b7.addActionListener(new ActionListener() {
           public void actionPerformed(ActionEvent e) {
             f4.setVisible(true);
             f3.setVisible(false);
             scrollPane.revalidate();
             scrollPane.repaint();
                  String namess = names.getText();
                 na.setText(namess);
                 String ownerslss = ownersls.getText();
                 ol.setText(ownerslss); 
                   String file_name =namess + " " + ownerslss + ".txt";
                                    na.setText(namess);

                 ol.setText(ownerslss); 
                 try { 
                   ReadFile file = new ReadFile (file_name);
                   String [] aryLines = file.OpenFile();
                    String aryLiness ="";
                   int item, space;
                   for (item=0; item < aryLines.length; item++) {
                     System.out.println(aryLines[item]);
                     aryLiness = Arrays.toString(aryLines);

                      space = aryLines.length;
                   }
                    space = aryLines.length;
    //< assname is a textarray that is the only way I could get the words to go down the page but it doesn't look good at all. Because it doesn't skip lines...
                   assname.setSize(20 ,space);
                   assname.append("" + aryLiness);
                     panimals.add(assname);  
                 }

                 catch (IOException wewe) {
                   System.out.println(wewe.getMessage() );

      }

     }
         });`

Answer 1

It's important to know how arrays work, because they are used very often.

String[] myStringArray = new String[3];

This array holds 3 String objects. It is essentially the same as if you had done:

String oneString = null;  //same as myStringArray[0]
String twoString = null;  //same as myStringArray[1]
String threeString = null;//same as myStringArray[2]

This means, after you read all your lines into Strings , you can create your JTextField like so:

JTextField myTextField1 = new JTextField(myStringArray[0]);
JTextField myTextField2 = new JTextField(myStringArray[1]);
JTextField myTextField3 = new JTextField(myStringArray[2]);

or, assigning an array one line at a time:

JTextField[] myTextFields = new JTextField[3];
myTextFields[0] = new JTextField(myStringArray[0]);
myTextFields[1] = new JTextField(myStringArray[1]);
myTextFields[2] = new JTextField(myStringArray[2]);

Now, imagine if you had 300 Strings and TextFields , there's no way you would want to type those lines 300 times. That's why for loops are awesome.

JTextField[] myTextFields = new JTextField[300];
for (int i = 0; i < myTextFields.length; i++)
{
    myTextFields[i] = new JTextField(myStringArray[i]);
}

---

Not sure if you realize, but you currently read every line in your textfile into an array already, named aryLines . You then print each String individually in your for loop:

System.out.println(aryLines[item]); //item is starting at 0, goes through every String

aryLines[0] is your first string. aryLines[1] is your second.. and so on until the last line. Theoretically, you could create a BufferedWriter like shown here and completely copy your current textfile into a new one just doing basically what you are already doing. You would just use this instead of the System.out.println() after creating your BufferedWriter:

writer.write(aryLines[item]);
writer.newLine();

---

After you print out every line to the console, I'm not sure what you mean to do. aryLiness with two ss is created by combining all the Strings in your array into one String. Then you set your TextArray with the entire combined String.