我想使用compareToIgnoreCase对字符串数组进行排序。
该字符串包含名称例如: 比利牛仔
当我尝试比较它们时,我得到一个空指针异常。我认为这是因为名字和姓氏之间的空白。我如何比较全名?Java比较器compareToIgnoreCase
感谢
class CompareStudentNames implements Comparator{
//Sorts the students by name ignoring case.
@Override
public int compare(Object o1, Object o2) {
String name1 = ((Student)o1).getName();
String name2 = ((Student)o2).getName();
return (name1.compareToIgnoreCase(name2));
}
}
编辑---附加在代码中使用比较学生姓名
private static void newInputFileReading(File f) throws FileNotFoundException{
String inputLine = null;
String [] inputSplit = new String[7];
Boolean proceed = false;
Scanner enterReader = new Scanner(System.in);
String name;
while(!proceed){
int stunum = -1;
try {
Scanner inputReader = new Scanner(f);
while(inputReader.hasNextLine()){
studentNM.add(new Student());
++stunum;
inputLine = inputReader.nextLine();
inputSplit = inputLine.split(",");
testForWord(inputSplit);
System.out.println(inputSplit[0]);
name = inputSplit[0];
System.out.println(name);
for(int i = 1; i<8; i++){
if(i == 0){
studentNM.get(stunum).setName(name);
}// where to send the name on run 0
else if(i <= 4 && i>0){
studentNM.get(stunum).setQuiz(testForDouble(inputSplit,i), i-1);
}// where to output to runs 1-4
else if(i>4 && i <= 6){
studentNM.get(stunum).setMids(testForDouble(inputSplit,i),i-5);
}// where to output on runs 5 & 6
else if(i> 6){
studentNM.get(stunum).setFinal(testForDouble(inputSplit,i));
}// where to output on the 7th run
}// for loop to assign the inputs
}// while scanner has next
proceed = true;
Collections.sort(studentNM, new CompareStudentNames());
}//try to initalize a new scanner and get & assign the inputs
catch (FileNotFoundException e) {
proceed = false;
studentNM.clear();
System.out.println("The file appears to have gone missing, please restart the program");
System.out.println("Press Enter to continue");
enterReader.nextLine();
System.out.println("");
}// catch a file not found exception
catch(formatError | NumberFormatException e){
proceed = false;
studentNM.clear();
System.out.printf("You input file is formatted incorrectly\nEvery line must start with a word,followed by 7 numbers, seperated by commas.\nPlease reformat your file and try again.\n");
System.out.println("Press Enter to continue");
enterReader.nextLine();
System.out.println("");
}// catch format error
catch (Exception e) {
proceed = false;
studentNM.clear();
System.out.println("An unknown error occured, please restart the program");
e.printStackTrace();
System.out.println("Press Enter to continue");
enterReader.nextLine();
System.out.println("");
}
}// while to make sure the first token is a word
}// newInputFileReading
我不认为Student对象越来越名称,因为
System.out.println(studentNM.get(0).getName());
显示为空;
你必须在使用'CompareStudentNames'的代码粘贴,所以我们可以看到如何创建和填写你的'Student'对象。 –
你在开始你的for循环'i = 1',但是设置名字'if(i == 0)'。 –
谢谢杰森,非常感谢! –