Read a file

**dmjpro** · Oct 16 '07, 03:58 AM

Originally posted by Jromero

My code
[

public class Student{
private String lastName;
private String firstName;
private String middleName;
private int sid;
private double units;
private String Programs;

public Student(){
this( "", "", "", 0, 0.0, "");
}

public Student (String lastName, String firstName, String middleName, int sid, double units, String Programs )
{
//setLastName(las tName);
setFirstName(fi rstName);
setMiddleName(m iddleName);
setsid(sid);
setunits(units) ;
setPrograms(Pro grams);

}

public void setLastName(Str ing lastName){
lastName = lastName;
}

public String getLastName(){
return lastName;
}

public void setFirstName(St ring firstName){
firstName = firstName;
}

public String getFirstName(){
return firstName;
}

public void setMiddleName(S tring middleName){
middleName = middleName;
}

public String getMiddleName() {
return middleName;
}

public void setsid(int sid){
sid = sid;
}
public int getsid(){
return sid;
}

public void setunits(double units){
units = units;
}

public double getunits()
{
return units;
}

public void setPrograms(Str ing Programs){
Programs = Programs;
}

public String getPrograms(){
return Programs;
}

}

]
Another class
[

import java.io.File;
import java.io.IOExcep tion;
import java.util.Scann er;

public class Roaster {

Student st[] = new Student[100];

/* public static void copyLines() throws IOException {
BufferedReader inputStream = null;
PrintWriter outputStream = null;

try {
inputStream =
new BufferedReader( new FileReader("roa ster.txt"));

for(i=0;i<no.of lines;i++)
{
addstudent(fir,
}
outputStream =
new PrintWriter(new FileWriter("cha racteroutput.tx t"));

String l;
while ((l = inputStream.rea dLine()) != null) {

outputStream.pr intln(l);
}
} finally {
if (inputStream != null) {
inputStream.clo se();
}
if (outputStream != null) {
outputStream.cl ose();
}
}
}*/

public void addStudentfromF ile() throws IOException
{
Scanner inputStream = null;
try {
inputStream =
new Scanner(new File("roaster.t xt"));
int noofstu = 1;

while (inputStream.ha sNext()) {

String temp = inputStream.nex t();
String[] name = null;
name = temp.split(",") ;
/* System.out.prin tln(name[0]);
System.out.prin tln(name[1]);
System.out.prin tln(inputStream .next());

System.out.prin tln(inputStream .nextInt());

System.out.prin tln(inputStream .nextDouble());
System.out.prin tln(inputStream .next());*/
st[noofstu-1] = new Student(name[0], name[1], inputStream.nex t(),inputStream .nextInt() , inputStream.nex tDouble(),input Stream.next());
noofstu++;
}
} finally {
if (inputStream != null) {
inputStream.clo se();
}

}

}

public int getStudentno(){
//getStudent = new Student;
return st.length;

}

public static void main(String[] args) {

}
}
]
Another class for testing
[
import java.io.Buffere dInputStream;
import java.io.Buffere dReader;
import java.io.DataInp utStream;
import java.io.File;
import java.io.FileInp utStream;
import java.io.FileRea der;
import java.io.IOExcep tion;

public class RoasterTest {

public static void main (String[] args) throws Exception{
File RoasterTest = new File( "roaster.tx t" );
if ( RoasterTest.exi sts() )
{
// Create the buffered reader for reading the file
BufferedReader inFile = new BufferedReader( new FileReader( RoasterTest ) );

// Get the first line of the file
String line = inFile.readLine ();

// If line is not end of file continue
while ( line != null )
{
// Create a StringTokenizer with a colon sign as a delimiter
java.util.Strin gTokenizer st =
new java.util.Strin gTokenizer( line, ":" );

// Display the content of the first token
System.out.prin t( " Name: " + st.nextToken() );

// Display the total number of tokens remaining this string
int numScores = st.countTokens( );

// Initialize the sum to zero
int sum = 0;

// Get each score, add it to the sum and print it
for ( int i=1; i <= numScores; i++ )
{
int score = Integer.parseIn t( st.nextToken() );
sum += score;
}

// Display the average score for this student
System.out.prin tln( " average = " + sum/numScores );

// Read next line of the file
line = inFile.readLine ();

} // end while not at end of file

// Close the BufferedReader
inFile.close();

// try {
// RoasterTest.clo ne();
// } catch (IOException ioe) {

} // end if the grade file doesn't exist

}

}

]

My test class does not read student class or roaster class .. I know I am missing something but I am loss

Use Code Tags.
Please post the file content.

Debasis Jana

**Jromero** · Oct 16 '07, 04:02 AM

My code
[

public class Student{
private String lastName;
private String firstName;
private String middleName;
private int sid;
private double units;
private String Programs;

public Student(){
this( "", "", "", 0, 0.0, "");
}

public Student (String lastName, String firstName, String middleName, int sid, double units, String Programs )
{
//setLastName(las tName);
setFirstName(fi rstName);
setMiddleName(m iddleName);
setsid(sid);
setunits(units) ;
setPrograms(Pro grams);

}

public void setLastName(Str ing lastName){
lastName = lastName;
}

public String getLastName(){
return lastName;
}

public void setFirstName(St ring firstName){
firstName = firstName;
}

public String getFirstName(){
return firstName;
}

public void setMiddleName(S tring middleName){
middleName = middleName;
}

public String getMiddleName() {
return middleName;
}

public void setsid(int sid){
sid = sid;
}
public int getsid(){
return sid;
}

public void setunits(double units){
units = units;
}

public double getunits()
{
return units;
}

public void setPrograms(Str ing Programs){
Programs = Programs;
}

public String getPrograms(){
return Programs;
}

}

]
Another class
[

import java.io.File;
import java.io.IOExcep tion;
import java.util.Scann er;

public class Roaster {

Student st[] = new Student[100];

/* public static void copyLines() throws IOException {
BufferedReader inputStream = null;
PrintWriter outputStream = null;

try {
inputStream =
new BufferedReader( new FileReader("roa ster.txt"));

for(i=0;i<no.of lines;i++)
{
addstudent(fir,
}
outputStream =
new PrintWriter(new FileWriter("cha racteroutput.tx t"));

String l;
while ((l = inputStream.rea dLine()) != null) {

outputStream.pr intln(l);
}
} finally {
if (inputStream != null) {
inputStream.clo se();
}
if (outputStream != null) {
outputStream.cl ose();
}
}
}*/

public void addStudentfromF ile() throws IOException
{
Scanner inputStream = null;
try {
inputStream =
new Scanner(new File("roaster.t xt"));
int noofstu = 1;

while (inputStream.ha sNext()) {

String temp = inputStream.nex t();
String[] name = null;
name = temp.split(",") ;
/* System.out.prin tln(name[0]);
System.out.prin tln(name[1]);
System.out.prin tln(inputStream .next());

System.out.prin tln(inputStream .nextInt());

System.out.prin tln(inputStream .nextDouble());
System.out.prin tln(inputStream .next());*/
st[noofstu-1] = new Student(name[0], name[1], inputStream.nex t(),inputStream .nextInt() , inputStream.nex tDouble(),input Stream.next());
noofstu++;
}
} finally {
if (inputStream != null) {
inputStream.clo se();
}

}

}

public int getStudentno(){
//getStudent = new Student;
return st.length;

}

public static void main(String[] args) {

}
}

import java.io.Buffere dInputStream;
import java.io.Buffere dReader;
import java.io.DataInp utStream;
import java.io.File;
import java.io.FileInp utStream;
import java.io.FileRea der;
import java.io.IOExcep tion;

public class RoasterTest {

public static void main (String[] args) throws Exception{
File RoasterTest = new File( "roaster.tx t" );
if ( RoasterTest.exi sts() )
{
// Create the buffered reader for reading the file
BufferedReader inFile = new BufferedReader( new FileReader( RoasterTest ) );

// Get the first line of the file
String line = inFile.readLine ();

// If line is not end of file continue
while ( line != null )
{
// Create a StringTokenizer with a colon sign as a delimiter
java.util.Strin gTokenizer st =
new java.util.Strin gTokenizer( line, ":" );

// Display the content of the first token
System.out.prin t( " Name: " + st.nextToken() );

// Display the total number of tokens remaining this string
int numScores = st.countTokens( );

// Initialize the sum to zero
int sum = 0;

// Get each score, add it to the sum and print it
for ( int i=1; i <= numScores; i++ )
{
int score = Integer.parseIn t( st.nextToken() );
sum += score;
}

// Display the average score for this student
System.out.prin tln( " average = " + sum/numScores );

// Read next line of the file
line = inFile.readLine ();

} // end while not at end of file

// Close the BufferedReader
inFile.close();

// try {
// RoasterTest.clo ne();
// } catch (IOException ioe) {

} // end if the grade file doesn't exist

}

}

]

This is my code

**dmjpro** · Oct 16 '07, 04:10 AM

Look, have look at "ObjectInputStr eam","ObjectOut putStream" and "Serializat ion" in java.
Have a look through Google.
Any further problem, please post here.

Debasis Jana

**Jromero** · Oct 16 '07, 05:00 AM

I still don't get it please help me

**dmjpro** · Oct 16 '07, 05:41 AM

Originally posted by Jromero

I still don't get it please help me

Look,
"ObjectInputStr eam" for object reading from a stream,
and "ObjectOutputSt ream" for object writing for a strean.
Now the Object should implement "Serializab le" interface.

Have a look at this sample code ...............

[code=java]
ObjectOutputStr eam o = new OutjectOutputSt ream(new FileOutputStrea m("test.dat") );
Student s = new Student(/*Some data goes here*/);
o.writeObject(s );
.
.
ObjectInputStre am i = new ObjectInputStre am(new FileInputStream ("test.dat") );
Student _s = (Student)i.read Object();
//now access the _s object.
[/code]

Your Student class should be like this .......
[code=java]
class Student implements Serializable
{
//your code goes here
}
[/code]

Debasis Jana

**Jromero** · Oct 16 '07, 06:00 AM

The
Code[
ObjectOutputStr eam o = new ObjectOutputStr eam(new FileOutputStrea m("roaster.txt" ));
Student s = new Student("String lastName, String firstName, String middleName, int sid, double units, String Programs", null, null, 0, 0, null);
o.writeObject(s );

ObjectInputStre am i = new ObjectInputStre am(new FileInputStream ("roaster.txt") );
Student _s = (Student)i.read Object();
// now access the _s object.

]
Goes in Roaster class

**dmjpro** · Oct 16 '07, 06:07 AM

You got your code worked?

Actually I forgot to close the streams.
See the code carefully.
[code=java]
ObjectOutputStr eam o = new OutjectOutputSt ream(new FileOutputStrea m("test.dat") );
Student s = new Student(/*Some data goes here*/);
o.writeObject(s );
o.close();
.
.
ObjectInputStre am i = new ObjectInputStre am(new FileInputStream ("test.dat") );
Student _s = (Student)i.read Object();
i.close();
//now access the _s object.
[/code]

Your Student class should be like this .......
[code=java]
class Student implements Serializable
{
//your code goes here
}
[/code]

Debasis Jana

**Jromero** · Oct 17 '07, 12:17 AM

I am still having problems I don't where to put the object stream

Read a file

Read a file

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