在Java中写入文本文件时如何插入换行

Question

I would like to create a simple program (in Java) which edits text files - particularly one which performs inserting arbitrary pieces of text at random positions in a text file.

Old Text file:

Noodles
Cereal
Tomato
Carrot
Fish
Meat

Output:

Please insert new record:
1
Cornflake

Please insert new record:

New Text File:

Noodles
Cereal
Tomato
Carrot
Fish
Meat
Cornflake

I check on my text file and it insert into my text file but when I run program again, for example, I want to insert Ice-Cream then it should added after Cornflake but instead it replace Cornflake with Ice-Cream. But how can I resolve this problem?

Java:

String INPUT_PROMPT ="Please insert new record:";
BufferedReader reader = new BufferedReader
                    (new InputStreamReader (System.in));
            line = reader.readLine();

while(!line.equals("x"))
{ 
          switch(line)
          {       
              case "1":
              line = reader.readLine();  

                    FileWriter fw=new FileWriter(inFile);
                    BufferedWriter bw=new BufferedWriter(fw);
                    PrintWriter pw=new PrintWriter(bw);

                    for(int k=0; k< prdct.size(); k++)
                    {
                        pw.println(prdct.get(k).toString());
                    }
                    pw.write(line);
                    pw.write("\n");
                    pw.close();    
                    break;
          }  
            System.out.println(INPUT_PROMPT);
            line = reader.readLine();  


}

Answer 1

This question is probably a duplicate of many others, but you need to open the FileWriter in append mode, which is done by passing true as the second parameter in the constructor:

FileWriter fw = new FileWriter(inFile, true);

From the Javadoc for FileWriter(File file, boolean append) :

Constructs a FileWriter object given a File object. If the second argument is true, then bytes will be written to the end of the file rather than the beginning.