Java创建文件并向其添加字符串

问题描述

创建多个文件并向其写入字符串的代码，直到此处代码运行正常并创建五个文件，名称为name1.txt ...，name5.txt

the code that creates multiple files and write string to it,till here the code runs fine and creates five files with names name1.txt...,name5.txt

public static void main(String[] args) throws IOException
{
  BufferedWriter writer = null;
  for(int i=1 ; i<=5 ; i++){
  String fileName = "name" + i + ".txt";

但写字符串的时候

but when write string to it

package Io;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.logging.Level;
import java.util.logging.Logger;

public class ForFilesWriter
{

public static void main(String[] args) throws IOException
{
  BufferedWriter writer = null;
  for(int i=1 ; i<=5 ; i++){
  String fileName = "name" + i + ".txt";
  PrintWriter printer = new PrintWriter(fileName, "UTF-8");
  writer.write("Java is object oriented");
  writer.close();
}}} 

引用：

esception是

the esception is

引用：

线程mainjava中的异常.lang.NullPointerException

在Io.ForFilesWriter.main（ForFilesWriter.java:27）

C：\ Users \Admin \ AppData \ Local \ NetBeans \Cache \8.2 \ executor-snippets\run.xml：53：Java返回：1

BUILD FAILED（总时间：0秒）

Exception in thread "main" java.lang.NullPointerException
at Io.ForFilesWriter.main(ForFilesWriter.java:27)
C:\Users\Admin\AppData\Local\NetBeans\Cache\8.2\executor-snippets\run.xml:53: Java returned: 1
BUILD FAILED (total time: 0 seconds)

代码应该创建五个不同的文件并写入字符串



我有什么尝试过：



更改了代码并添加了各种组合

the code is supposed to create five different files and write string to it

What I have tried:

changed code and added various combinations

推荐答案

PrintWriter printer = new PrintWriter(fileName, "UTF-8");
//writer.write("Java is object oriented");
//writer.close();
printer.write("Java is object oriented");
printer.close();

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