Java Basics 115 – Writing Text File
STEPS
1) OPEN STARTUP PROJECT
2) Add Java Class.
2-1) Right-click Package name. Select New/Java Class.
2-2) Set Class Name as WriteFile.
Delete all comments and unnecessary codes, leaving only the following codes.
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public class WriteFile {
}
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3) Add Import Statements.
package textfiles;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.io.IOException;
public class WriteFile {
}
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4) Add instructions to WriteFile Class.
4-1) Add variables and a constructor.
package textfiles;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.io.IOException;
public class WriteFile {
private String path;
private boolean append_to_file = false;
public WriteFile(String file_path) {
path = file_path;
}
}
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4-2) Add a second constructor.
package textfiles;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.io.IOException;
public class WriteFile {
private String path;
private boolean append_to_file = false;
public WriteFile(String file_path) {
path = file_path;
}
public WriteFile(String file_path, boolean append_value) {
path = file_path;
append_to_file = append_value;
}
}
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4-3) Add method to write file.
package textfiles;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.io.IOException;
public class WriteFile {
private String path;
private boolean append_to_file = false;
public WriteFile(String file_path) {
path = file_path;
}
public WriteFile(String file_path, boolean append_value) {
path = file_path;
append_to_file = append_value;
}
public void writeToFile(String textLine) throws IOException {
FileWriter write = new FileWriter(path, append_to_file);
PrintWriter print_line = new PrintWriter(write);
print_line.printf("%s" + "%n", textLine);
print_line.close();
}
}
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5) Implement File Writing in Main Method
5-1) Append codes to the end of the existing codes.
package textfiles;
import java.io.IOException;
public class FileData {
public static void main(String[] args) throws IOException {
String file_name = "C:/test.txt";
try {
ReadFile file = new ReadFile(file_name);
String[] aryLines = file.OpenFile();
int i;
for (i = 0; i < aryLines.length; i++) {
System.out.println(aryLines[ i]);
}
} catch (IOException e) {
System.out.println(e.getMessage());
}
/* WRITING DATA TO FILE */
WriteFile data = new WriteFile( file_name , true );
data.writeToFile( "This is another line of text" );
System.out.println( "Text File Written To" );
}
}
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5-2) Run.
5-3) Run again.
5-3) Modify the codes to add TRY…CATCH Block.
package textfiles;
import java.io.IOException;
public class FileData {
public static void main(String[] args) throws IOException {
String file_name = "C:/test.txt";
try {
ReadFile file = new ReadFile(file_name);
String[] aryLines = file.OpenFile();
int i;
for (i = 0; i < aryLines.length; i++) {
System.out.println(aryLines[ i]);
}
} catch (IOException e) {
System.out.println(e.getMessage());
}
/* WRITING DATA TO FILE */
try {
WriteFile data = new WriteFile(file_name, true);
data.writeToFile("This is another line of text");
System.out.println("Text File Written To");
} catch (IOException e) {
System.out.println(e.getMessage());
}
}
}
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