所以这里我有代码我有HashMap由文件中的单词组成,我正在添加单词并将它们写在文件上并且它可以正常工作,但是当我使用我的删除函数进行一些reaseon时,这里没有做任何事情是代码:
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
public class Main {
public static File file = new File( C:\\Users\\N\\Desktop\\Newfolder\\Dictionary\\src\\nmishewa\\geekycamp\\dictionary\\bg_win1251.txt");
public static int value = 1;
private static Scanner input;
public static Scanner in = new Scanner(System.in);
public static Map<String, Integer> map = new HashMap<String, Integer>();
public static void main(String[] args) throws FileNotFoundException {
readFile();
System.out.println("Enter number of function wanted" + "\n1 to add"
+ "\n2 for searching by prefix" + "\n3 for deleting");
int choice = in.nextInt();
if (choice == 1) {
System.out.println("enter words seprated by comma");
String wd = in.next();
add(wd);
}
if (choice == 2) {
System.out.println("Enter prefix");
String wd = in.next();
prefixSearch(wd);
}
if (choice == 3) {
System.out.println("ENTER word to delete");
String wd = in.next();
remove(wd);
}
}
public static void readFile() throws FileNotFoundException {
input = new Scanner(file);
boolean done = false;
int value = 1;
while (input.hasNext()) {
String word = input.next().toLowerCase();
String[] line = word.split("[,\\s]+");
for (int j = 0; j < line.length; j++) {
map.put(line[j], value);
value++;
done = true;
}
}
if (done == true) {
System.out.println("Succes");
}
}
public static void prefixSearch(String wd) {
System.out.println("Enter prefix");
String prefix = wd.toLowerCase();
for (Map.Entry<String, Integer> key : map.entrySet()) {
if (key.getKey().startsWith(prefix)) {
System.out.println(key.getKey());
}
}
}
public static void add(String wd) {
boolean done = false;
String word = wd.toLowerCase();
String[] line = word.split("[,\\s]+");
for (int j = 0; j < line.length; j++) {
if (!map.containsKey(line[j])) {
map.put(line[j], value);
value++;
try {
FileWriter fw = new FileWriter(file.getAbsoluteFile());
BufferedWriter bw = new BufferedWriter(fw);
bw.write(map.toString());
bw.close();
done = true;
} catch (Exception e) {
e.printStackTrace();
}
} else {
continue;
}
}
if (done == true) {
System.out.println("Success");
}
}
public static void remove(String wd) {
boolean done = false;
String word = wd.toLowerCase();
String[] line = word.split("[,\\s]+");
for (int j = 0; j < line.length; j++) {
for (Map.Entry<String, Integer> key : map.entrySet()) {
if (key.getKey().equals(line[j])) {
map.remove(key.getKey(), key.getValue());
try {
FileWriter fw = new FileWriter(file.getAbsoluteFile());
BufferedWriter bw = new BufferedWriter(fw);
bw.write(map.toString());
bw.close();
done = true;
} catch (Exception e) {
e.printStackTrace();
}
} else {
continue;
}
}
}
if (done == true) {
System.out.println("Succes");
}
}
}
其他每种方法都运行正常,但请删除。循环是否有问题,可能使用更优化的方式或?
答案 0 :(得分:0)
我在代码中可以看到的问题如下:
在定义文件时忘记了引用:
public static File file = new File( C:\\Users\\N\\Desktop\\Newfolder\\Dictionary\\src\\nmishewa\\geekycamp\\dictionary\\bg_win1251.txt")
应该是:
public static File file = new File("C:\\Users\\N\\Desktop\\Newfolder\\Dictionary\\src\\nmishewa\\geekycamp\\dictionary\\bg_win1251.txt");
地图中的remove()函数只接收一个参数,这是您要删除的条目的键,因此:
map.remove(key.getKey(), key.getValue());
应该是:
map.remove(key.getKey());
此外,由于您获取了地图的entrySet,因此您可以考虑将rename()函数中的key
变量重命名为entry
。
答案 1 :(得分:0)
失败的原因是您在迭代条目时尝试更改地图。与任何集合一样 - 如果您在迭代时尝试修改它,您将获得ConcurrentModificationException
。
此外,还有一个冗余的内部for循环(冗余,因为地图的整个目的是当你正在寻找一个特定的值时,你不必迭代它)这意味着当只有一次足够时,你会尝试多次覆盖该文件。
public static void remove(String wd) {
boolean done = false;
String word = wd.toLowerCase();
String[] line = word.split("[,\\s]+");
for (int j = 0; j < line.length; j++) {
map.remove(line[j]);
}
try {
FileWriter fw = new FileWriter(file.getAbsoluteFile());
BufferedWriter bw = new BufferedWriter(fw);
bw.write(map.toString());
bw.close();
done = true;
} catch (Exception e) {
e.printStackTrace();
}
if (done == true) {
System.out.println("Success");
}
}