How to write a file in java

Java method of writing files:

1. FileWritter writes files

FileWritter, character stream writes characters to file. By default, it will replace all existing content with new content, as follows:

new FileWriter(file);

However, when specifying a true (Boolean) value as the second parameter of the FileWritter constructor, it will retain the existing content. content, and append new content at the end of the file, as follows:

new FileWriter(file,true);

Example:

package com.andy.file;
import java.io.File;
import java.io.FileWriter;
import java.io.BufferedWriter;
import java.io.IOException;
public class AppendToFileTest
{
public static void main( String[] args ) 
{ 
    try{ 
        String content = "A cat will append to the end of the file";
        File file =new File("test_appendfile.txt");
        if(!file.exists()){ 
            file.createNewFile(); 
        } 
        //使用true，即进行append file 
        FileWriter fileWritter = new FileWriter(file.getName(),true);
        BufferedWriter bufferWritter = new BufferedWriter(fileWritter); 
        bufferWritter.write(content);
        bufferWritter.close(); 
        System.out.println("finish"); 
    }catch(IOException e){ 
        e.printStackTrace(); 
    }
}
}

2. BufferedWriter writes to the file

Buffered Character (BufferedWriter) is a character stream class to process character data, but it is different from the byte stream (data is converted into bytes). You can directly write strings, arrays or character data and save them to files.

Example:

package com.andy.file; 
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter; 
import java.io.IOException; 
public class WriteToFileTest2 {
	public static void main(String[] args) {		
		try {
				String content = "a dog will be write in file";
				File file = new File("test_appendfile2.txt");
				if(!file.exists()){
					file.createNewFile();
				}
				FileWriter fileWriter = new FileWriter(file.getAbsoluteFile());
				BufferedWriter bw = new BufferedWriter(fileWriter);
				bw.write(content);
				bw.close();
				System.out.println("finish");
		    } catch (IOException e) {
		        e.printStackTrace();
		    }
	} 
}

For more java knowledge, please pay attention to the java basic tutorial column.

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