java 运行出现的 空指针异常 问题求大神帮忙看一下

public class CountOccurenceOfWords {
public static void main(String[] args){
// String text = "Good morning.Have a good class." +
// "Have a good vist. Hava fun!";

CountWords a = new CountWords("Good morning.Have a good class." +
"Have a good vist. Hava fun!");
a.printResult();
}
}

class CountWords{
private String text;

public CountWords(String text){
this.text = text;
}

Map<String, Integer> map = new TreeMap<String, Integer>();

//我debug了一下是这里没有给words赋上值，但是不知道为什么

String[] words = text.split("[ \n\t\r.,;:!?()]");

public void printResult(){
for(int i=0; i<words.length; i++){
String key = words[i].toLowerCase();

if(key.length() > 0){
if(map.get(key) == null){
map.put(key, 1);
}else{
int value = map.get(key).intValue(); //这里要加上intValue（）；
value++;
map.put(key, value);
}
}
}

Set<Map.Entry<String, Integer>> entrySet = map.entrySet();

for(Map.Entry<String, Integer> entry : entrySet){
System.out.println(entry.getKey() + entry.getValue());
}
}
}

Exception in thread "main" java.lang.NullPointerException
at Unit_22.CountWords.<init>(CountOccurenceOfWords.java:26)
at Unit_22.CountOccurenceOfWords.main(CountOccurenceOfWords.java:11)
public void printResult(){
for(int i=0; i<words.length; i++){
String key = words[i].toLowerCase();

if(key.length() > 0){
if(map.get(key) == null){
map.put(key, 1);
}else{
int value = map.get(key).intValue(); //这里要加上intValue（）；
value++;
map.put(key, value);
}
}
}

把错误代码贴全点，你可以自己设断点debug啊，一步步看是谁是空指针就可以了

你的split用了几种分割标准啊？

class CountWords { private String text; private String[] words; public CountWords(String text) { this.text = text; words = this.text.split("[ \n\t\r.,;:!?()]"); } Map<String, Integer> map = new TreeMap<String, Integer>(); public void printResult() {