我收到 java.lang.OutOfMemoryError 异常:Java 堆空间。
我正在解析一个 XML 文件，存储数据并在解析完成时输出一个 XML 文件。
得到这样的错误我有点惊讶，因为原始的 XML 文件一点也不长。
最佳答案
解释为什么你有 OutOfMemoryError 的简短答案，对于文件中找到的每个质心，你循环遍历已经“注册”的质心以检查它是否已知(添加新的或更新已注册的质心) .但是对于每次失败的比较，您都会添加新质心的新副本。因此，对于每个新的质心，它添加它的次数与列表中已经存在的质心一样多，然后您遇到您添加的第一个质心，更新它并离开循环......
这里是一些重构代码:
public class CentroidGenerator {
final Map<String, Centroid> centroids = new HashMap<String, Centroid>();
public Collection<Centroid> getCentroids() {
return centroids.values();
}
public void nextItem(FlickrDoc flickrDoc) {
final String event = flickrDoc.getEvent();
final Centroid existingCentroid = centroids.get(event);
if (existingCentroid != null) {
existingCentroid.update(flickrDoc);
} else {
final Centroid newCentroid = new Centroid(flickrDoc);
centroids.put(event, newCentroid);
}
}
public static void main(String[] args) throws IOException, SAXException {
// instantiate Digester and disable XML validation
[...]
// now that rules and actions are configured, start the parsing process
CentroidGenerator abp = (CentroidGenerator) digester.parse(new File("PjrE.data.xml"));
Writer writer = null;
try {
File fileOutput = new File("centroids.xml");
writer = new BufferedWriter(new FileWriter(fileOutput));
writeOuput(writer, abp.getCentroids());
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (writer != null) {
writer.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
private static void writeOuput(Writer writer, Collection<Centroid> centroids) throws IOException {
writer.append("<?xml version='1.0' encoding='utf-8'?>" + System.getProperty("line.separator"));
writer.append("<collection>").append(System.getProperty("line.separator"));
for (Centroid centroid : centroids) {
writer.append("<doc>" + System.getProperty("line.separator"));
writer.append("<title>" + System.getProperty("line.separator"));
writer.append(centroid.getTitle());
writer.append("</title>" + System.getProperty("line.separator"));
writer.append("<description>" + System.getProperty("line.separator"));
writer.append(centroid.getDescription());
writer.append("</description>" + System.getProperty("line.separator"));
writer.append("<time>" + System.getProperty("line.separator"));
writer.append(centroid.getTime());
writer.append("</time>" + System.getProperty("line.separator"));
writer.append("<tags>" + System.getProperty("line.separator"));
writer.append(centroid.getTags());
writer.append("</tags>" + System.getProperty("line.separator"));
writer.append("<geo>" + System.getProperty("line.separator"));
writer.append("<lat>" + System.getProperty("line.separator"));
writer.append(centroid.getLat());
writer.append("</lat>" + System.getProperty("line.separator"));
writer.append("<lng>" + System.getProperty("line.separator"));
writer.append(centroid.getLng());
writer.append("</lng>" + System.getProperty("line.separator"));
writer.append("</geo>" + System.getProperty("line.separator"));
writer.append("</doc>" + System.getProperty("line.separator"));
}
writer.append("</collection>" + System.getProperty("line.separator") + System.getProperty("line.separator"));
}
/**
* JavaBean class that holds properties of each Document entry. It is important that this class be public and
* static, in order for Digester to be able to instantiate it.
*/
public static class FlickrDoc {
private String id;
private String title;
private String description;
private String time;
private String tags;
private String latitude;
private String longitude;
private String event;
public void setId(String newId) {
id = newId;
}
public String getId() {
return id;
}
public void setTitle(String newTitle) {
title = newTitle;
}
public String getTitle() {
return title;
}
public void setDescription(String newDescription) {
description = newDescription;
}
public String getDescription() {
return description;
}
public void setTime(String newTime) {
time = newTime;
}
public String getTime() {
return time;
}
public void setTags(String newTags) {
tags = newTags;
}
public String getTags() {
return tags;
}
public void setLatitude(String newLatitude) {
latitude = newLatitude;
}
public String getLatitude() {
return latitude;
}
public void setLongitude(String newLongitude) {
longitude = newLongitude;
}
public String getLongitude() {
return longitude;
}
public void setEvent(String newEvent) {
event = newEvent;
}
public String getEvent() {
return event;
}
}
public static class Centroid {
private final String event;
private String title;
private String description;
private String tags;
private Integer time;
private int nbTimeValues = 0; // needed to calculate the average later
private Float latitude;
private int nbLatitudeValues = 0; // needed to calculate the average later
private Float longitude;
private int nbLongitudeValues = 0; // needed to calculate the average later
public Centroid(FlickrDoc flickrDoc) {
event = flickrDoc.event;
title = flickrDoc.title;
description = flickrDoc.description;
tags = flickrDoc.tags;
if (flickrDoc.time != null) {
time = Integer.valueOf(flickrDoc.time.trim());
nbTimeValues = 1; // time is the sum of one value
}
if (flickrDoc.latitude != null) {
latitude = Float.valueOf(flickrDoc.latitude.trim());
nbLatitudeValues = 1; // latitude is the sum of one value
}
if (flickrDoc.longitude != null) {
longitude = Float.valueOf(flickrDoc.longitude.trim());
nbLongitudeValues = 1; // longitude is the sum of one value
}
}
public void update(FlickrDoc newData) {
title = title + " " + newData.title;
description = description + " " + newData.description;
tags = tags + " " + newData.tags;
if (newData.time != null) {
nbTimeValues++;
if (time == null) {
time = 0;
}
time += Integer.valueOf(newData.time.trim());
}
if (newData.latitude != null) {
nbLatitudeValues++;
if (latitude == null) {
latitude = 0F;
}
latitude += Float.valueOf(newData.latitude.trim());
}
if (newData.longitude != null) {
nbLongitudeValues++;
if (longitude == null) {
longitude = 0F;
}
longitude += Float.valueOf(newData.longitude.trim());
}
}
public String getTitle() {
return title;
}
public String getDescription() {
return description;
}
public String getTime() {
if (nbTimeValues == 0) {
return null;
} else {
return Integer.toString(time / nbTimeValues);
}
}
public String getTags() {
return tags;
}
public String getLat() {
if (nbLatitudeValues == 0) {
return null;
} else {
return Float.toString(latitude / nbLatitudeValues);
}
}
public String getLng() {
if (nbLongitudeValues == 0) {
return null;
} else {
return Float.toString(longitude / nbLongitudeValues);
}
}
public String getEvent() {
return event;
}
}
}
关于java - OutOfMemoryError 异常 : Java heap space, 如何调试...？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/5422762/