Although JAVA provides a variety of input and output stream methods and methods, it is not convenient for non-character data.Therefore, for the input and output of data such as int, it can only be “Eight Immortals Crossing the Sea, each showing supernatural power”.Here's a small example of writing and reading data to a file. Let's talk about the author's way. Hopefully it will help a beginner.
Problem Description:
The programming program generates 100 random numbers between 1 and 100 and writes them to a file, then reads them out of the file, sorts them, and writes them to another file.
Code:
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Import java.io.*; Import java.util.*; Public class WriteRead { Public static void main(String[] args) { Random rd=new Random(); Int nNum[]=new int[100]; For(int i=0;i<100;i++) { nNum[i]=(int)(rd.nextDouble()*100); //Generate 100 random numbers } // Write 100 integers to a file as a character stream Try { FileWriter file=new FileWriter("first.txt"); For(int i=0;i<nNum.length;i++) { String str=String.valueOf(nNum[i])+" "; //Convert the integer into a string, and add a space after it to separate each integer File.write(str); } File.close(); } Catch(IOException e) { System.out.println(e.toString()); } // Read 100 integers from the file, sort them, and write the data to a new file Try { FileReader fr=new FileReader("first.txt"); Int[] n=new int[100]; BufferedReader buff=new BufferedReader(fr); String str=""; //Read first.Txt file data (string form), stored in str While(true) { String line=buff.readLine(); //Read one line at a time to speed up the reading If(line==null) //Deciding if reading is complete Break; Str=str+line; } Buff.close(); / / Use the StringTokenizer class to split the string str, where the separator is a space StringTokenizer st=new StringTokenizer(str); For(int i=0;st.hasMoreTokens();i++) n[i]=Integer.parseInt(st.nextToken()); //convert the decomposed string to an integer and store it in an array Arrays.sort(n); //Sort //Write to file FileWriter file=new FileWriter("second.txt"); For(int i=0;i<n.length;i++) { String s=String.valueOf(n[i])+" " File.write(s); } File.close(); } Catch(IOException e) { System.out.println(e.toString()); } } } |
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Reprinted Note Source: Baiyuan's Blog>>https://wangbaiyuan.cn/en/java-inputoutput-streams-at-a-glance-2-2.html
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