String, read and write file problem...

[Tran Tuan Hung]

Dear all.
I have the following file

Animal; Light; Width; Height; Size // line 1
dog; lamp; 10; 20; 15 // line 2

Acc; Name; Phone; Address; ID; // line 3
Test; Peter; 900234; 10 Le Duan; 5 // line 4

So i would like to store the line 1 and line 3 with variables:
animal; light; width; height; size....
I would like to retrieve the data: animal = dog; light = lamp; width = 10; height = 20; size =15..... id = 5;
So please help me to slove my problem.
Thanks and best regards,

[Stan James]

How far have you gotten? It's hard to tell if you're stuck at reading files, parsing text or maybe digging into reflection to set variables. Show us what you have and we can see right where you're stuck.

[Jim Yingst]

If you're not sure where to begin, and you're using JDK 5 or later, I recommend you read Sun's tutorial on java.util.Scanner.

[Omar Omran]

you can paste the code here and point to the problem

[Tran Tuan Hung]

Ok here is my text file.

Animal; Light; Width; Height; Size // line 1
dog; lamp; 10; 20; 15 // line 2

here is my code:

  public class Model {
private String animal;
private String light;
private int width;
private int height;
private int size;
public static int DEFAULT_WIDTH = 0;
public static int DEFAULT_HEIGHT = 0;
public static int DEFAULT_SIZE = 0;
 
public Model() {
animal = "";
light = "";
width = DEFAULT_WIDTH;
height = DEFAULT_HEIGHT;
size = DEFAULT_SIZE;
}
 
public String getAnimal() {
return animal;
}
 
public void setAnimal(String animal) {
this.animal = animal;
}
 
public String getLight() {
return light;
}
 
public void setLight(String light) {
this.light = light;
}
 
public int getWidth() {
return width;
}
 
public void setWidth(int width) {
this.width = width;
}
 
public int getHeight() {
return height;
}
 
public void setHeight(int height) {
this.height = height;
}
 
public int getSize() {
return size;
}
 
public void setSize(int size) {
this.size = size;
}
 
public String toString() {
String result = " ";
result = result + animal + " ";
result = result + light + " ";
result = result + width + " ";
result = result + height + " ";
result = result + size + " ";
return result;
}
 
}  

and here is main class:

 import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
 
public class ModelTest {
private String filePath = "D://OK/Test.txt";
private String line;
 
public void Test() throws FileNotFoundException,NumberFormatException,ArrayIndexOutOfBoundsException {
FileReader fileReader = new FileReader(filePath);
Model model = new Model();
BufferedReader in = new BufferedReader(fileReader);
try {
while ((line = in.readLine())!= null) {
if (line.startsWith("Animal")) {
String nextLine = in.readLine();
String[] info = nextLine.split(";");
System.out.println("Size: " + info.length);
System.out.println(nextLine);// it is OK
model.setAnimal(info[0]);
model.setLight(info[1]);
model.setWidth(Integer.parseInt(info[2]));
model.setHeight(Integer.parseInt(info[3]));
model.setSize(Integer.parseInt(info[4]));
System.out.println(model.toString());// why it doesn't show on the console
System.out.println("OK");// it also not show 
}
}
} catch (Exception e) {
// TODO: handle exception
}
}
 
public static void main(String[] args) throws FileNotFoundException {
ModelTest mt = new ModelTest();
mt.Test();
}
 
}
   

1- It doesn't report the error but still not show on the console.
2- For now the file have form following:

12:14:16; acc ; name; id; size

The first field is time format (hh:mm:ss)so i cannot use startWith() method , because it is change follow the time. Please suggest me the solution
Sorry for my bad english.

[Jim Yingst]

[Tran]: 1- It doesn't report the error but still not show on the console.

} catch (Exception e) {
// TODO: handle exception
}

This is very important - your catch block doesn't do anything. It could be catching an error here, but since there's no code inside the catch block, it does nothing with the error, and then the program continues. This is very bad - it hides the error from the programmer (you).

To fix this you can either (a) put e.printStackTrace() inside the catch block (or some other code which reports the error somehow), or (b) remove the try/catch and just let the exception be thrown. You may need to add some more exceptions to the "throws" clause if you do this.

[Tran]: 2- For now the file have form following:
quote:
12:14:16; acc ; name; id; size

The first field is time format (hh:mm:ss)so i cannot use startWith() method , because it is change follow the time. Please suggest me the solution

You could try something like

if (Character.isDigit(line.charAt(0))) {

That assumes that the only lines that start with digits (numbers) are the lines that start with times. If there are also other types of lines with numbers, then you will need something more complex. A regular expression would be a good general solution. That may take some time to understand if you're not familiar with regular expressions, but they're very useful to know about. I don't know if you need to know about them for this problem, but you should learn about them eventually.

Some other notes:

public static int DEFAULT_WIDTH = 0;

If this is intended to be a constant, you probably want to add "final" to the modifiers here.

private String filePath = "D://OK/Test.txt";

Is this on Windows, or some sort of Unix? On Windows you probably want to use \\ rather than /. Java may "correct" this for you in some cases, but in general it's easier to be consistent in the first place - use the separator that's appropriate for your system.

private String line;

There's no reason for "line" to be declared as part of the class. It's only used within one method, and you don't need to remember any previous value from the last time the method was called. So it's better to just declare the variable within that method, as close as possible to where it's used.

public String toString() {
String result = " ";
result = result + animal + " ";
result = result + light + " ";
result = result + width + " ";
result = result + height + " ";
result = result + size + " ";
return result;
}

While this works, it's generally a very inefficient way to manipulate Strings. What happen is, it gets converted into something like this:

String result = " ";
 
StringBuilder sb = new StringBuilder();
sb.append(result);
sb.append(animal);
sb.append(" ");
result = sb.toString();
 
sb = new StringBuilder();
sb.append(result);
sb.append(light);
sb.append(" ");
result = sb.toString();
 
sb = new StringBuilder();
sb.append(result);
sb.append(width);
sb.append(" ");
result = sb.toString();
 
sb = new StringBuilder();
sb.append(result);
sb.append(height);
sb.append(" ");
result = sb.toString();
 
sb = new StringBuilder();
sb.append(result);
sb.append(size);
sb.append(" ");
result = sb.toString();

Every time you use + in a new expression, it creates a new StringBuilder to get the result. It's better (and simpler) to just put these all in one line:

public String toString() {
    return animal + " " + light + " " + width + " " + height + " " + size + " ";
}

This is equivalent to

public String toString() {
    StringBuilder sb = new StringBuilder();
    sb.append(animal);
    sb.append(" ");
    sb.append(light);
    sb.append(" ");
    sb.append(width);
    sb.append(" ");
    sb.append(height);
    sb.append(" ");
    sb.append(size);
    return sb.toString();
}

which is much less work for the JVM.

[Tran Tuan Hung]

you are the man Jim Yingst , thanks thanks you very much .
if for now my file have format following:

9:12:05;MS Healthy Message

030000002f130200000000000800450000800000000001119f7a0a000000e0e02f13c5dac5da006c00000000000003030000000000

04000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

00000000000000000000000000000000000000000000000000000000000000000000000000
9:13:58;MS Healthy Message
0300000032330200000000000800450000800000000001119c5a0a000000e0e03233c5dac5da006c0000000000000303000000000

00400000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

000000000000000000000000000000000000000000000000000000000000000000000000000

For now, i have 3 fields:
1- formatTime variable (hh:mm:ss);
2- a typeMsg variable is type Message.
3- a byte array with byteArr: (private byte byteArr
"030000002f130200000000000800450000800000000001119f7a0a000000e0e02f13c5dac5da006c000000000000030300

00000000040000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

0000000000000000000000000000000000000000000000000000000000000000000000000000000000"
I dont know how to show the byteArr.
thanks and regards,
great forum