我试图弄清楚为什么每次调用的返回方法都在for循环中时我的代码都会创建一个新行。主for循环中的if语句检查名为list的数组列表中的每个Student对象。完成比较学生i和学生j（学生j是第二个for循环）之后。一旦学生找到了最佳匹配，就应该打印出一条声明，说明他/她是否与某人匹配。
这是 应该归还的内容 ：
Abey matches with Melissa with score 60
John matches with Jeff with score 100
Craig has no matches.
相反 ，它会返回：
Abey matches with
Melissa with score 60
John matches with
Jeff with score 100
Craig has no matches.
以下是代码：
for (int i = 0; i < list.size(); i++) {
int maxScore = 0;
int currentScore = 0;
int bestMatchScore = 0;
int bestMatchStudent = 0;
if (!list.get(i).isMatched()) {
for (int j = i; j < list.size(); j++) {
if (!list.get(j).isMatched()) {
if (j != i) {
currentScore = list.get(i).compare(list.get(j));
if (currentScore > maxScore) {
maxScore = currentScore;
bestMatchStudent = j;
bestMatchScore = maxScore;
}
}
}
}
if(bestMatchScore == 0) {
System.out.println(list.get(i).getName() + " has no matches.");
}
else {
list.get(i).setMatched(list.get(bestMatchStudent));
System.out.println(list.get(i).getName() + " matches with " + list.get(bestMatchStudent).getName() + " with score " + maxScore);
}
}
}
如果我要删除if-else语句中的所有getName（），我会得到一个类似于我想要的输出：
Student@6d3552ed matches with Student@47d77d9e with score 60
Student@147834eb matches with Student@5fda3acc with score 100
Student@704a583d has no matches.
我怀疑它必须通过调用getName方法来做某事。它只是一种存取方法......
以下是重现问题的所有代码：
学生班级
public class Student {
private String name;
private char gender;
private Date birthdate;
private Preference pref;
private boolean matched;
public Student(String name, char gender, Date birthdate, Preference pref) {
this.name = name;
this.gender = gender;
this.birthdate = birthdate;
this.pref = pref;
}
public String getName() {
return name;
}
public char getGender() {
return gender;
}
public Date getBirthdate() {
return birthdate;
}
public Preference getPref() {
return pref;
}
public boolean isMatched() {
return matched;
}
public void setMatched() {
this.matched = true;
}
public void setMatched(Student roommate) {
setMatched();
roommate.setMatched();
}
public int compare(Student st) {
if (st.getGender() != gender)
return 0;
return Math.abs((40 - pref.compare(st.getPref())) + (60 - birthdate.compare(st.getBirthdate())));
}
}
匹配班级
import java.io.*;
import java.util.Scanner;
import java.util.*;
public class Match {
public static void main(String[] args) throws FileNotFoundException {
//Student[] fullRoster = new Student[5]; converted to ArrayList
ArrayList<Student> list = new ArrayList<Student>();
String fileName = "Students.txt";
Scanner input = new Scanner(new FileReader(fileName));
input.useDelimiter("[\t\r-]");
//int studentIndex = 0; converted to ArrayList
while(input.hasNext()) {
String name = input.next();
//System.out.println(name);
char gender = input.next().charAt(0);
//System.out.println(gender);
int month = Integer.parseInt(input.next());
//System.out.println(month);
int day = Integer.parseInt(input.next());
//System.out.println(day);
int year = Integer.parseInt(input.next());
//System.out.println(year);
Date birthday = new Date(year, month, day);
//System.out.println(birthday); //Printed out birthday
int pref1 = Integer.parseInt(input.next());
//System.out.println(pref1);
int pref2 = Integer.parseInt(input.next());
//System.out.println(pref2);
int pref3 = Integer.parseInt(input.next());
//System.out.println(pref3);
int pref4 = Integer.parseInt(input.next());
//System.out.println(pref4);
Preference pref = new Preference(pref1, pref2, pref3, pref4);
//System.out.println(pref); //Printed out pref
//fullRoster[studentIndex] = new Student(name, gender, birthday, pref); converted to ArrayList
list.add(new Student(name, gender, birthday, pref));
//studentIndex++; converted to ArrayList
}
input.close();
for (int i = 0; i < list.size(); i++) {
int maxScore = 0;
int currentScore = 0;
int bestMatchScore = 0;
int bestMatchStudent = 0;
if (!list.get(i).isMatched()) {
for (int j = i; j < list.size(); j++) {
if (!list.get(j).isMatched()) {
if (j != i) {
currentScore = list.get(i).compare(list.get(j));
if (currentScore > maxScore) {
maxScore = currentScore;
bestMatchStudent = j;
bestMatchScore = maxScore;
}
}
}
}
if(bestMatchScore == 0) {
System.out.println(list.get(i) + " has no matches.");
}
else {
list.get(i).setMatched(list.get(bestMatchStudent));
System.out.println(list.get(i).getName() + " matches with " + list.get(bestMatchStudent) + " with score " + maxScore);
}
}
}
}
}
偏好类
public class Preference {
private int quietTime, music, reading, chatting;
public Preference(int quietTime, int music, int reading, int chatting) {
this.quietTime = quietTime;
this.music = music;
this.reading = reading;
this.chatting = chatting;
}
public int getQuietTime() {
return quietTime;
}
public int getMusic() {
return music;
}
public int getReading() {
return reading;
}
public int getChatting() {
return chatting;
}
public int compare(Preference pref) {
int difference = 0;
difference += Math.abs(pref.getQuietTime() - this.getQuietTime());
difference += Math.abs(pref.getMusic() - this.getMusic());
difference += Math.abs(pref.getReading() - this.getReading());
difference += Math.abs(pref.getChatting() - this.getChatting());
return difference;
}
}
日期类
public class Date {
int year, month, day;
public Date(int year, int month, int day) {
this.year = year;
this.month = month;
this.day = day;
}
public int getYear() {
return year;
}
public int getMonth() {
return month;
}
public int getDay() {
return day;
}
public int compare(Date dt) {
int yearsDifferenceInDays = (Math.abs(year - dt.getYear())) * 365;
int daysDifference = Math.abs(dt.dayOfYear() - this.dayOfYear());
int totalDifference = Math.abs(yearsDifferenceInDays - daysDifference);
int monthsDifference = totalDifference / 30;
if(monthsDifference > 60)
return 60;
return monthsDifference;
}
public int dayOfYear() {
int totalDays = 0;
switch (month) {
case 12: totalDays += 30;
case 11: totalDays += 31;
case 10: totalDays += 30;
case 9 : totalDays += 31;
case 8 : totalDays += 31;
case 7 : totalDays += 30;
case 6 : totalDays += 31;
case 5 : totalDays += 30;
case 4 : totalDays += 31;
case 3 : totalDays += 28;
case 2 : totalDays += 31;
}
totalDays += day;
return totalDays;
}
}
匹配班级
import java.io.*;
import java.util.Scanner;
import java.util.*;
public class Match {
public static void main(String[] args) throws FileNotFoundException {
//Student[] fullRoster = new Student[5]; converted to ArrayList
ArrayList<Student> list = new ArrayList<Student>();
String fileName = "Students.txt";
Scanner input = new Scanner(new FileReader(fileName));
input.useDelimiter("[\t\r-]");
//int studentIndex = 0; converted to ArrayList
while(input.hasNext()) {
String name = input.next();
//System.out.println(name);
char gender = input.next().charAt(0);
//System.out.println(gender);
int month = Integer.parseInt(input.next());
//System.out.println(month);
int day = Integer.parseInt(input.next());
//System.out.println(day);
int year = Integer.parseInt(input.next());
//System.out.println(year);
Date birthday = new Date(year, month, day);
//System.out.println(birthday); //Printed out birthday
int pref1 = Integer.parseInt(input.next());
//System.out.println(pref1);
int pref2 = Integer.parseInt(input.next());
//System.out.println(pref2);
int pref3 = Integer.parseInt(input.next());
//System.out.println(pref3);
int pref4 = Integer.parseInt(input.next());
//System.out.println(pref4);
Preference pref = new Preference(pref1, pref2, pref3, pref4);
//System.out.println(pref); //Printed out pref
//fullRoster[studentIndex] = new Student(name, gender, birthday, pref); converted to ArrayList
list.add(new Student(name, gender, birthday, pref));
//studentIndex++; converted to ArrayList
}
input.close();
for (int i = 0; i < list.size(); i++) {
int maxScore = 0;
int currentScore = 0;
int bestMatchScore = 0;
int bestMatchStudent = 0;
if (!list.get(i).isMatched()) {
for (int j = i; j < list.size(); j++) {
if (!list.get(j).isMatched()) {
if (j != i) {
currentScore = list.get(i).compare(list.get(j));
if (currentScore > maxScore) {
maxScore = currentScore;
bestMatchStudent = j;
bestMatchScore = maxScore;
}
}
}
}
if(bestMatchScore == 0) {
System.out.println(list.get(i) + " has no matches.");
}
else {
list.get(i).setMatched(list.get(bestMatchStudent));
System.out.println(list.get(i).getName() + " matches with " + list.get(bestMatchStudent) + " with score " + maxScore);
}
}
}
}
}
Students.txt
Abey F 5-5-1996 0 0 0 0
John M 5-5-1997 10 10 10 10
Melissa F 5-5-1996 10 10 10 10
Craig M 5-5-1998 5 5 5 5
Jeff M 5-5-1997 10 10 10 10
答案 0 :(得分：2)
如果我要删除if-else语句中的所有getName（），我会得到一个类似于我想要的输出：
Student@6d3552ed matches with Student@47d77d9e with score 60 Student@147834eb matches with Student@5fda3acc with score 100 Student@704a583d has no matches.
此处解释了该输出How do I print my Java object without getting "SomeType@2f92e0f4"?
好像你需要trim()这个名字。
取决于您希望＆＃34;输入验证的位置＆＃34;要进行改造，你可以在输入时做到这一点。
String name = input.next().trim();
或者在构造函数
中public Student(String name, char gender, Date birthdate, Preference pref) {
this.name = name.trim();
this.gender = gender;
this.birthdate = birthdate;
this.pref = pref;
}
或者在吸气器中
public String getName() {
return name.trim();
}
或者当您实际显示println
或定义toString()，如return name.trim();的其他帖子中所述，并按照您的方式打印list.get(i)。
根本问题可能是您没有将LF（\n）或CRLF（\r\n）定义为分隔符。
input.useDelimiter("[\t\r-]");
尝试
input.useDelimiter("\r\n|[\t\r\n-]");
答案 1 :(得分：1)
我可以给出一个解决方案来解决这个问题： 没有像以下一样打印整体：
System.out.println(list.get(i).getName() + " matches with " + list.get(bestMatchStudent).getName() + " with score " + maxScore);
按如下方式进行：
String name = list.get(i).getName().trim();
String bestMachStudentName = list.get(bestMatchStudent).getName().trim();
if(!name .equals("") && !bestMachStudentName.equals("") ){
System.out.println( name + " matches with " + bestMachStudentName + " with score " + maxScore);
}
else{
// other stuff......
}
我不知道为什么这个println()函数表现得像从列表中获取值可能会出现问题。
我希望它能正常运作。