Java 将布尔值设置为true，但filewriter仍会覆盖文件，有什么建议吗？
我创建了一个简单的程序，使用不同的算法对输入文件中的整数进行排序。我还使用filewriter将结果输出到另一个文件。不幸的是，无论我如何更改代码，文件都会被覆盖。有什么建议吗 一直在谷歌上搜索答案，并试图改变我输入语法的方式，但没有任何效果 重要信息： 设置编写器Java 将布尔值设置为true，但filewriter仍会覆盖文件，有什么建议吗？,java,filewriter,Java,Filewriter,我创建了一个简单的程序，使用不同的算法对输入文件中的整数进行排序。我还使用filewriter将结果输出到另一个文件。不幸的是，无论我如何更改代码，文件都会被覆盖。有什么建议吗 一直在谷歌上搜索答案，并试图改变我输入语法的方式，但没有任何效果 重要信息： 设置编写器 try { FileWriter fileWriter = new FileWriter ("Sorted output.txt"); //BufferedWriter bufferedWrite
try {
FileWriter fileWriter = new FileWriter ("Sorted output.txt");
//BufferedWriter bufferedWriter = new BufferedWriter (fileWriter);
PrintWriter out = new PrintWriter (new FileWriter("Sorted output.txt", true));
out.println("User's own data set sorted using bubble sort.");
out.println(unsortedArray + Arrays.deepToString(FileOne));
out.println("Sorted Array looks like this:" + Arrays.toString(intArrayBubble));
out.println(timeToSort + bubbleSortIs + bubbleTime + "ms");
import java.io.*;
import java.util.*;
import java.util.concurrent.TimeUnit;
public class PDD_Sorting {
public static void main (String [] pArgs)
{
//Array for a file
String[] FileOne;
FileOne = new String[0];
int optionOne = 1,
optionTwo = 2,
optionThree = 3,
secondaryOptionOne = 1,
secondaryOptionTwo = 2,
secondaryOptionThree = 3,
userSelection,
subUserSelection;
String unsortedArray = "Unsorted array is: ",
bubbleSort = "Sorted array using bubble sort: ",
selectionSort = "Sorted array using selection sort: ",
insertionSort = "Sorted array using insertion sort: ",
timeToSort = "Time needed to sort this array using ",
bubbleSortIs = "bubble sort is ",
selectionSortIs = "selection sort is ",
insertionSortIs = "insertion sort is ",
welcomeToSorter = "Welcome to the SORTER - program that can sort your txt files containing integeres in an ascending order!",
notFiles = "Integers, not files :)",
pleaseSelect = "Please select one of the following options, by enetering a number asociated with it.",
optionOneUserInput = "1. Sort your own data set - input your own set of data (integers, separated by colons, no spaces) into the Input file.",
optionTwoPredefined = "2. Use predetermind set of data to test the algorythms.",
optionThreeExit = "3. Exit the program.",
subMenuPleaseSelect = "Please select which algorythm would you like to use to sort this file.",
optionBubble = "(1) - Bubble Sort.",
optionSelection = "(2) - Selection Sort.",
optionInsertion = "(3) - Insertion Sort.",
usersDataBubble = "User's own data set sorted using bubble sort.",
sortedArrayLooks = "Sorted Array looks like this:",
msTime = "ms",
usersDataSelection = "User's own data set sorted using selection sort.",
usersDataInsertion = "User's own data set sorted using insertion sort.",
validOption = "Please enter a valid option i.e. 1,2 or 3",
lessThanZero = "If time shown in ms is 0, that means the time needed to conduct the sort is shorter than 1ms.",
fileCreated = "File created.",
terminatingProgram = "Terminating the program.",
unableToWriteFile = "Unable to write to file";
System.out.println(welcomeToSorter);
System.out.println(notFiles);
Scanner tInput = new Scanner (System.in);
try {
FileWriter fileWriter = new FileWriter ("Sorted output.txt");
//BufferedWriter bufferedWriter = new BufferedWriter (fileWriter);
PrintWriter out = new PrintWriter (new FileWriter("Sorted output.txt", true));
do {
System.out.println(pleaseSelect);
System.out.println(optionOneUserInput);
System.out.println(optionTwoPredefined);
System.out.println(optionThreeExit);
// Scanner tInput = new Scanner (System.in);
userSelection = tInput.nextInt();
if (userSelection == optionOne) {
//System.out.println("Please enter a valid path for your file.");
String[] splitFile = null;
//String userFile = tInput.next();
FileOne = getAndPrepareFile(splitFile);
System.out.println(subMenuPleaseSelect);
System.out.println(optionBubble);
System.out.println(optionSelection);
System.out.println(optionInsertion);
subUserSelection = tInput.nextInt();
if (subUserSelection == secondaryOptionOne) {
int size = FileOne.length;
int [] intArrayBubble = new int [size];
for(int i=0; i<size; i++) {
intArrayBubble[i] = Integer.parseInt(FileOne[i]);
}
bubbleSort(intArrayBubble);
long bubbleTime = timeCount(intArrayBubble);
out.println(usersDataBubble);
out.println(unsortedArray + Arrays.deepToString(FileOne));
out.println(sortedArrayLooks + Arrays.toString(intArrayBubble));
out.println(timeToSort + bubbleSortIs + bubbleTime + msTime);
}
else if (subUserSelection == secondaryOptionTwo) {
int size2 = FileOne.length;
int [] intArraySelection = new int [size2];
for(int i=0; i<size2; i++) {
intArraySelection[i] = Integer.parseInt(FileOne[i]);
}
doSelectionSort(intArraySelection);
long selectionTime = timeCount(intArraySelection);
out.println(usersDataSelection);
out.println(unsortedArray + Arrays.deepToString(FileOne));
out.println(sortedArrayLooks + Arrays.toString(intArraySelection));
out.println(timeToSort + selectionSortIs + selectionTime + msTime);
}
else if (subUserSelection == secondaryOptionThree) {
int size3 = FileOne.length;
int [] intArrayInsertion = new int [size3];
for(int i=0; i<size3; i++) {
intArrayInsertion[i] = Integer.parseInt(FileOne[i]);
}
doInsertionSort(intArrayInsertion);
long insertionTime = timeCount(intArrayInsertion);
out.println(usersDataInsertion);
out.println(unsortedArray + Arrays.deepToString(FileOne));
out.println(sortedArrayLooks + Arrays.toString(intArrayInsertion));
out.println(timeToSort + insertionSortIs + insertionTime + msTime);
}
else {
System.out.println(validOption);
tInput.next();
}
}
else if (userSelection == optionTwo){
//file being prepared and loaded via function
String[] splitFilePredefined = null;
FileOne = getAndPrepareFilePredefined(splitFilePredefined);
//converting string array into int array so the method can sort it.
int size = FileOne.length;
int [] intArrayBubble = new int [size];
for(int i=0; i<size; i++) {
intArrayBubble[i] = Integer.parseInt(FileOne[i]);
}
int size2 = FileOne.length;
int [] intArraySelection = new int [size2];
for(int i=0; i<size2; i++) {
intArraySelection[i] = Integer.parseInt(FileOne[i]);
}
int size3 = FileOne.length;
int [] intArrayInsertion = new int [size3];
for(int i=0; i<size3; i++) {
intArrayInsertion[i] = Integer.parseInt(FileOne[i]);
}
//inserting pre-prepared int arrays into variables including a timecount method
int bubbleTime = timeCount(intArrayBubble);
int selectionTime = timeCount(intArraySelection);
int insertionTime = timeCount(intArrayInsertion);
//sorting array using various sorts
bubbleSort(intArrayBubble);
doSelectionSort(intArraySelection);
doInsertionSort(intArrayInsertion);
//out.println("Sorted arrray using insertion sort looks like this: " + Arrays.toString(intArrayInsertion));
out.println(timeToSort + bubbleSortIs + bubbleTime + "ms");
out.println(timeToSort + selectionSortIs + selectionTime + "ms");
out.println(timeToSort + insertionSortIs + insertionTime + "ms");
out.println(lessThanZero);
System.out.println(fileCreated);
}
else if (userSelection == optionThree){
System.out.println(terminatingProgram);
System.exit(0);
}
else {
System.out.println(validOption);
tInput.next();
}
out.flush();
out.close();
//tInput.close();
}while (userSelection != optionThree);
}
catch (Exception e)
{
System.out.println(unableToWriteFile);
tInput.next();
}
tInput.close();
}//end main
//method that fetches the file from predefined, hardcoded location and removes comas, esentially prepares the file for the next phase
private static String[] getAndPrepareFile (String[] splitFile)
{
Scanner fileIn = null;
try
{
fileIn = new Scanner(new FileInputStream("C:\\Users\\Greg\\Documents\\Programming\\PDD - Assignment 1\\Input.txt"));
String fileNew = fileIn.next();
splitFile = fileNew.split(",");
//System.err.println(Arrays.toString(splitFile)); //Arrays.toString needed to print the array correctly, otherwise it prints the address of the object
fileIn.close();
}
catch (IOException e)
{
System.out.println("File not found.");
//System.exit(0);
}
return splitFile;
}
//as above but works for predefined file, that can be generated using randomNumber.java program
private static String[] getAndPrepareFilePredefined (String[] splitFilePredefined)
{
Scanner fileIn = null;
try
{
fileIn = new Scanner(new FileInputStream("C:\\Users\\Greg\\Documents\\Programming\\PDD - Assignment 1\\Generated input.txt"));
String fileNew = fileIn.next();
splitFilePredefined = fileNew.split(",");
//System.err.println(Arrays.toString(splitFile)); //Arrays.toString needed to print the array correctly, otherwise it prints the address of the object
fileIn.close();
}
catch (IOException e)
{
System.out.println("File not found.");
//System.exit(0);
}
return splitFilePredefined;
}
//method used to sort a file using bubble sort
private static void bubbleSort(int[] arr) {
int n = arr.length;
int temp = 0;
for(int i=0; i < n; i++){
for(int j=1; j < (n-i); j++){
if(arr[j-1] > arr[j]){
//swap elements
temp = arr[j-1];
arr[j-1] = arr[j];
arr[j] = temp;
}
}
}
}
//method used to sort a file using selection sort
private static int[] doSelectionSort(int[] arr){
for (int i = 0; i < arr.length - 1; i++)
{
int index = i;
for (int j = i + 1; j < arr.length; j++)
if (arr[j] < arr[index])
index = j;
int smallerNumber = arr[index];
arr[index] = arr[i];
arr[i] = smallerNumber;
}
return arr;
}
//method used to sort a file using sinsertion sort
private static int[] doInsertionSort(int[] input){
int temp;
for (int i = 1; i < input.length; i++) {
for(int j = i ; j > 0 ; j--){
if(input[j] < input[j-1]){
temp = input[j];
input[j] = input[j-1];
input[j-1] = temp;
}
}
}
return input;
}
//method used to calculate how much time has lapsed while using any of the given sort methods, outputs in ms, if less than 1 ms, outputs 0ms
private static int timeCount (int[] anArray)
{
long start = System.nanoTime();
Arrays.sort(anArray);
long end = System.nanoTime();
long timeInMillis = TimeUnit.MILLISECONDS.convert(end - start, TimeUnit.NANOSECONDS);
//System.out.println("Time spend in ms: " + timeInMillis);
return (int) timeInMillis;
}
}//end class
import java.io.*；
导入java.util.*；
导入java.util.concurrent.TimeUnit；
公共类PDU排序{
公共静态void main（字符串[]pArgs）
{
//文件的数组
字符串[]FileOne；
FileOne=新字符串[0]；
int optionOne=1，
选项wo=2，
选项树=3，
二次芳基选择酮=1，
第二选项wo=2，
第二选项树=3，
用户选择，
子用户选择；
字符串unsortedArray=“unsortedArray为：”，
bubbleSort=“使用冒泡排序进行排序的数组：”，
selectionSort=“使用选择排序对数组进行排序：”，
insertionSort=“使用插入排序对数组进行排序：”，
timeToSort=“使用排序此数组所需的时间”，
bubbleSortIs=“气泡排序为”，
selectionSortIs=“选择排序为”，
insertionSortIs=“插入排序为”，
welcomeToSorter=“欢迎使用SORTER-程序，该程序可以按升序对包含整数的txt文件进行排序！”，
notFiles=“整数，而不是文件：）”，
pleaseSelect=“请通过输入与之相关的数字，选择以下选项之一。”，
optionOneUserInput=“1.对您自己的数据集进行排序-将您自己的数据集（整数，用冒号分隔，无空格）输入到输入文件中。”，
optiontw预定义=“2.使用预先确定的数据集测试算法。”，
optionThreeExit=“3.退出程序。”，
子菜单PleaseSelect=“请选择要用于对该文件排序的算法。”，
optionBubble=“（1）-气泡排序。”，
optionSelection=“（2）-选择排序。”，
optionInsertion=“（3）-插入排序。”，
usersDataBubble=“用户自己的数据集使用气泡排序进行排序。”，
SorterDarrayLooks=“排序数组如下所示：”，
msTime=“ms”，
usersDataSelection=“使用选择排序对用户自己的数据集进行排序。”，
UsersDainservation=“用户自己的数据集使用插入排序进行排序。”，
validOption=“请输入有效选项，即1、2或3”，
lessThanZero=“如果以毫秒为单位显示的时间为0，则表示进行排序所需的时间小于1ms。”，
fileCreated=“文件已创建。”，
terminatingProgram=“正在终止程序。”，
unableToWriteFile=“无法写入文件”；
System.out.println（welcomeToSorter）；
System.out.println（notFiles）；
扫描器输入=新扫描器（系统输入）；
试一试{
FileWriter FileWriter=newfilewriter（“Sorted output.txt”）；
//BufferedWriter BufferedWriter=新的BufferedWriter（fileWriter）；
PrintWriter out=新的PrintWriter（新的FileWriter（“Sorted output.txt”，true））；
做{
系统输出打印项次（请选择）；
System.out.println（可选中性输入）；
System.out.println（optiontwo预定义）；
System.out.println（可选退出）；
//扫描器输入=新扫描器（系统输入）；
userSelection=tInput.nextInt（）；
if（userSelection==optionOne）{
//System.out.println（“请输入文件的有效路径”）；
String[]splitFile=null；
//字符串userFile=tInput.next（）；
FileOne=getAndPrepareFile（splitFile）；
System.out.println（子菜单请选择）；
System.out.println（optionBubble）；
系统输出打印LN（选项选择）；
System.out.println（可选输入）；
subUserSelection=tInput.nextInt（）；
if（subUserSelection==secondaryOptionOne）{
int size=FileOne.length；
int[]intarraybuble=新的int[size]；
对于（int i=0；i您不需要第一个FileWriter FileWriter=newfilewriter（“Sorted output.txt”）；
；这实际上是在创建/覆盖文件，然后您的PrintWriter会再次打开文件进行附加
所以，只要改变
// ... omitting beginning
try {
FileWriter fileWriter = new FileWriter ("Sorted output.txt");
//BufferedWriter bufferedWriter = new BufferedWriter (fileWriter);
PrintWriter out = new PrintWriter (new FileWriter("Sorted output.txt", true));
do {
// ... omitting rest
到
您不需要第一个FileWriter FileWriter=new FileWriter（“Sorted output.txt”）；
；这实际上是在创建/覆盖文件，然后您的PrintWriter会再次打开它进行附加
所以，只要改变
// ... omitting beginning
try {
FileWriter fileWriter = new FileWriter ("Sorted output.txt");
//BufferedWriter bufferedWriter = new BufferedWriter (fileWriter);
PrintWriter out = new PrintWriter (new FileWriter("Sorted output.txt", true));
do {
// ... omitting rest
到
移出。循环外的close（）
else {
System.out.println("Please enter a valid option i.e. 1,2 or 3");
tInput.next();
}
out.flush();
/* THIS -> out.close(); <- THIS */
//tInput.close();
}while (userSelection != optionThree);
out.close();
}
else{
System.out.println（“请输入有效选项，即1、2或3”）；
tInput.next（）；
}
out.flush（）；
/*这->out.close（）；将out.close（）移出循环
else {
System.out.println("Please enter a valid option i.e. 1,2 or 3");
tInput.next();
}
out.flush();
/* THIS -> out.close(); <- THIS */
//tInput.close();
}while (userSelection != optionThree);
out.close();
}
else{
System.out.println（“请输入有效选项，即1、2或3”）；
tInput.next（）；
}
out.flush（）；
/*这->out.close（）；这只会导致文件在每次运行时被覆盖，但我认为@Gregory Sky希望在用户每次运行时“附加”输出