Java FileWriter构造函数中的值。否则，它将简单地用新内容覆盖outfile（请参阅）

PrintWriter writer2=新的PrintWriter（新文件编写器（“numbers.dat”，true）

正如Govan提到的，你并没有关闭writer2。这就是为什么您的文件是空白的。如果调用writer2.close，将调用BufferedWriter的“flush”方法。“flush”实际上是强制写入程序将数据写入文件（）

正如Bharat提到的，您应该重新编写循环以使用“i”变量来编写，而不是sumeen。按照sumEven的编写方式，您将获得以下内容：

i=1，sumEven=sumEven+i+1=0+1+1=2

i=3，sumEven=sumEven+i+1=2+3+1=6

i=5，sumEven=sumEven+i+1=6+5+1=12

有几件事：

对于第二个writer（writer2），您需要在FileWriter构造函数中传递一个“true”值。否则，它将简单地用新内容覆盖outfile（请参阅）

PrintWriter writer2=新的PrintWriter（新文件编写器（“numbers.dat”，true）

正如Govan提到的，你并没有关闭writer2。这就是为什么您的文件是空白的。如果调用writer2.close，将调用BufferedWriter的“flush”方法。“flush”实际上是强制写入程序将数据写入文件（）

正如Bharat提到的，您应该重新编写循环以使用“i”变量来编写，而不是sumeen。按照sumEven的编写方式，您将获得以下内容：

i=1，sumEven=sumEven+i+1=0+1+1=2

i=3，sumEven=sumEven+i+1=2+3+1=6

i=5，sumEven=sumEven+i+1=6+5+1=12

---

您的第一个循环可以是这样的

for (i = 0; i < 100 ; i+2)
{ 
   if (i != 0) {
    writer.print(", ");
   } 
    writer.print(i+2);
}   

（i=0；i<100；i+2）的

{ 
如果（i！=0）{
作者：印刷体（“，”）；
} 
编印（i+2）；
}   

第二个应该是这样的

for (i = 0; i < 100 ; i+2)
{ 
    writer.print( ", " +(i+1));
}   

（i=0；i<100；i+2）的

{ 
writer.print（“，”+（i+1））；
}   

---

否则，您必须在行的末尾加一个逗号

您的第一个循环可以是这样的

for (i = 0; i < 100 ; i+2)
{ 
   if (i != 0) {
    writer.print(", ");
   } 
    writer.print(i+2);
}   

（i=0；i<100；i+2）的

{ 
如果（i！=0）{
作者：印刷体（“，”）；
} 
编印（i+2）；
}   

第二个应该是这样的

for (i = 0; i < 100 ; i+2)
{ 
    writer.print( ", " +(i+1));
}   

（i=0；i<100；i+2）的

{ 
writer.print（“，”+（i+1））；
}   

---

否则，您必须在行的末尾加一个逗号

我对您的代码做了几处更改

首先，你不需要两个作家，也不需要两个读者

您的单个写入程序可以写入偶数和奇数，因为您只写入一个文件。我将考虑两个作者的场景是，如果你同时编写一个奇数文件和一个偶数文件，则

不管怎么说，我只是把那些毛茸茸的东西注释掉了。如果删除所有注释，代码应该更简单、更有效，尤其是可读性更强

import java.io.*;
    import java.util.*;
    public class TextFileIO {
        public static void main(String[] args) throws Exception {
            //Clear the contents of numbers.dat if already exists and populated
            File fileOne = new File("numbers.dat");
            fileOne.delete();
            File newFile = new File("numbers.dat");
            newFile.createNewFile();
            //Create writer object
            PrintWriter writer = new PrintWriter(new FileWriter("numbers.dat"));
            //Loop from 1 to 100
            for (int i = 1; i <= 100; i++) {
                //If number is even, write to file  
                if (i % 2 == 0) {
                    writer.print(i + ",");
                }
            }
            //Close writer object.
            //writer.close();
            //Read from file
            //FileInputStream fileStream = new FileInputStream("numbers.dat");
            //DataInputStream in = new DataInputStream(fileStream);
            //BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            //Print line
            //System.out.println(reader.readLine());
            //reader.close();
            //Write all odd numbers to file
            //PrintWriter writer2 = new PrintWriter(new FileWriter("numbers.dat"));
            //Loop from 1 to 100
            for (int i = 1; i <= 100; i++) {
                //If number is odd, write to file  
                if (i % 2 == 1) {
                    writer.print(i + ",");
                }
            }
            writer.close();
            //Read from file
            FileInputStream fileStream2 = new FileInputStream("numbers.dat");
            DataInputStream in2 = new DataInputStream(fileStream2);
            BufferedReader reader2 = new BufferedReader(new InputStreamReader(in2));
            //Print line
            System.out.println(reader2.readLine());
            reader2.close();
        }


    }

import java.io.*；
导入java.util.*；
公共类TextFileIO{
公共静态void main（字符串[]args）引发异常{
//清除numbers.dat的内容（如果已存在并已填充）
File fileOne=新文件（“numbers.dat”）；
fileOne.delete（）；
File newFile=新文件（“numbers.dat”）；
createNewFile（）；
//创建编写器对象
PrintWriter writer=新的PrintWriter（新文件编写器（“numbers.dat”）；
//从1循环到100
对于（inti=1；i我对代码做了一些更改

首先，你不需要两个作家，也不需要两个读者

<> P>你的一个作者可以写偶数和奇数，因为你只写一个文件。如果你同时写一个奇数文件和一个偶数文件，我会考虑两个作者。
不管怎么说，我只是注释掉了一些无关紧要的东西。如果删除所有注释，代码应该更简单、更有效，尤其是更可读

import java.io.*;
    import java.util.*;
    public class TextFileIO {
        public static void main(String[] args) throws Exception {
            //Clear the contents of numbers.dat if already exists and populated
            File fileOne = new File("numbers.dat");
            fileOne.delete();
            File newFile = new File("numbers.dat");
            newFile.createNewFile();
            //Create writer object
            PrintWriter writer = new PrintWriter(new FileWriter("numbers.dat"));
            //Loop from 1 to 100
            for (int i = 1; i <= 100; i++) {
                //If number is even, write to file  
                if (i % 2 == 0) {
                    writer.print(i + ",");
                }
            }
            //Close writer object.
            //writer.close();
            //Read from file
            //FileInputStream fileStream = new FileInputStream("numbers.dat");
            //DataInputStream in = new DataInputStream(fileStream);
            //BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            //Print line
            //System.out.println(reader.readLine());
            //reader.close();
            //Write all odd numbers to file
            //PrintWriter writer2 = new PrintWriter(new FileWriter("numbers.dat"));
            //Loop from 1 to 100
            for (int i = 1; i <= 100; i++) {
                //If number is odd, write to file  
                if (i % 2 == 1) {
                    writer.print(i + ",");
                }
            }
            writer.close();
            //Read from file
            FileInputStream fileStream2 = new FileInputStream("numbers.dat");
            DataInputStream in2 = new DataInputStream(fileStream2);
            BufferedReader reader2 = new BufferedReader(new InputStreamReader(in2));
            //Print line
            System.out.println(reader2.readLine());
            reader2.close();
        }


    }

import java.io.*；
导入java.util.*；
公共类TextFileIO{
公共静态void main（字符串[]args）引发异常{
//清除numbers.dat的内容（如果已存在并已填充）
File fileOne=新文件（“numbers.dat”）；
fileOne.delete（）；
File newFile=新文件（“numbers.dat”）；
createNewFile（）；
//创建编写器对象
PrintWriter writer=新的PrintWriter（新文件编写器（“numbers.dat”）；
//从1循环到100
对于（int i=1；i）您正在定义要为文件创建的writer2，但您正在关闭writer！writer.newLine（）；writer.close（）；如果你想写偶数或奇数，你必须用2而不是i来增加SumeEven！那么，我应该在哪里关闭writer呢？在第一个循环之后，你是在关闭writer。然后你在创建writer 2，但在第二个循环之后，你是在关闭writer而不是writer 2。我认为这只是一个复制粘贴错误。因为你已经有了c一次丢失的writer！@Govan：你能检查一下我更新的代码和评论吗？@Serenity接受一个答案，如果这有助于你获得想要的结果？你正在定义要为文件创建的writer2，但你正在关闭writer！writer.newLine（）；writer.close（）；如果你想写偶数或奇数，你必须用2而不是i来增加SumeEven！那么，我应该在哪里关闭writer呢？在第一个循环之后，你是在关闭writer。然后你在创建writer 2，但在第二个循环之后，你是在关闭writer而不是writer 2。我认为这只是一个复制粘贴错误。因为你已经有了c失败者作家一次！@Govan:你能检查一下我更新的代码和评论吗？@Serenity接受一个答案，如果这有助于你获得想要的结果？试试新的…你应该打印
i
而不是
sumeen
试试新的…你应该打印
i
而不是
sumeen
嗨..我已经更新了my代码..你能帮我吗
public class textFileIO {
    public static void main(String[] args) throws Exception {
        //Clear the contents of numbers.dat if already exists and populated
        File fileOne = new File("numbers.dat");
        fileOne.delete();
        File newFile = new File("numbers.dat");
        newFile.createNewFile();
        //Create writer object
        PrintWriter writer = new PrintWriter(new FileWriter("numbers.dat"));
        //Loop from 1 to 100
        for (int i = 1; i <= 100; i++) {
            //If number is even, write to file  
            if (i % 2 == 0) {
                writer.print(i + ",");
            }
        }
        //Close writer object.
        writer.close();
        //Read from file
        FileInputStream fileStream = new FileInputStream("numbers.dat");
        DataInputStream in = new DataInputStream(fileStream);
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        //Print line
        System.out.println(reader.readLine());
        reader.close();
        //Write all odd numbers to file
        PrintWriter writer2 = new PrintWriter(new FileWriter("numbers.dat"));
        //Loop from 1 to 100
        for (int i = 1; i <= 100; i++) {
            //If number is odd, write to file  
            if (i % 2 == 1) {
                writer2.print(i + ",");
            }
        }
        writer2.close();
        //Read from file
        FileInputStream fileStream2 = new FileInputStream("numbers.dat");
        DataInputStream in2 = new DataInputStream(fileStream2);
        BufferedReader reader2 = new BufferedReader(new InputStreamReader(in2));
        //Print line
        System.out.println(reader2.readLine());
        reader.close();
    }
}

for (i = 0; i < 100 ; i+2)
{ 
   if (i != 0) {
    writer.print(", ");
   } 
    writer.print(i+2);
}   

for (i = 0; i < 100 ; i+2)
{ 
    writer.print( ", " +(i+1));
}   

import java.io.*;
    import java.util.*;
    public class TextFileIO {
        public static void main(String[] args) throws Exception {
            //Clear the contents of numbers.dat if already exists and populated
            File fileOne = new File("numbers.dat");
            fileOne.delete();
            File newFile = new File("numbers.dat");
            newFile.createNewFile();
            //Create writer object
            PrintWriter writer = new PrintWriter(new FileWriter("numbers.dat"));
            //Loop from 1 to 100
            for (int i = 1; i <= 100; i++) {
                //If number is even, write to file  
                if (i % 2 == 0) {
                    writer.print(i + ",");
                }
            }
            //Close writer object.
            //writer.close();
            //Read from file
            //FileInputStream fileStream = new FileInputStream("numbers.dat");
            //DataInputStream in = new DataInputStream(fileStream);
            //BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            //Print line
            //System.out.println(reader.readLine());
            //reader.close();
            //Write all odd numbers to file
            //PrintWriter writer2 = new PrintWriter(new FileWriter("numbers.dat"));
            //Loop from 1 to 100
            for (int i = 1; i <= 100; i++) {
                //If number is odd, write to file  
                if (i % 2 == 1) {
                    writer.print(i + ",");
                }
            }
            writer.close();
            //Read from file
            FileInputStream fileStream2 = new FileInputStream("numbers.dat");
            DataInputStream in2 = new DataInputStream(fileStream2);
            BufferedReader reader2 = new BufferedReader(new InputStreamReader(in2));
            //Print line
            System.out.println(reader2.readLine());
            reader2.close();
        }


    }

import java.io.*;
import java.util.*;
public class TextFileIO {
    public static void main(String[] args) throws Exception {
        //Clear the contents of numbers.dat if already exists and populated
        File fileOne = new File("numbers.dat");
        fileOne.delete();
        File newFile = new File("numbers.dat");
        newFile.createNewFile();
        //Create writer object
        PrintWriter writer = new PrintWriter(new FileWriter("numbers.dat"));
        //Loop from 1 to 100
        for (int i = 1; i <= 100; i++) {
            //If number is even, write to file  
            if (i % 2 == 0) {
                writer.print(i + ",");
            }
        }
        //Loop from 1 to 100
        for (int i = 1; i <= 100; i++) {
            //If number is odd, write to file  
            if (i % 2 == 1) {
                writer.print(i + ",");
            }
        }
        writer.close();
        //Read from file
        FileInputStream fileStream = new FileInputStream("numbers.dat");
        DataInputStream in = new DataInputStream(fileStream);
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        //Print line
        System.out.println(reader.readLine());
        reader.close();
    }
}