Out of memory java heap space
•浏览 1
Out of memory java heap space
我正在尝试将大量文件从服务器发送到多个客户端。当我尝试发送大小为 700mb 的文件时，它显示了"OutOfMemory java heap space"错误。我正在使用 Netbeans 7.1.2 版本。
我还在属性中尝试了 VMoption。但仍然发生同样的错误。我认为阅读整个文件存在一些问题。下面的代码最多可用于 300mb。请给我一些建议。
提前致谢
public class SplitFile {
static int fileid = 0 ;
public static DataUnit[] getUpdatableDataCode(File fileName) throws FileNotFoundException, IOException{
int i = 0;
DataUnit[] chunks = new DataUnit[UAProtocolServer.singletonServer.cloudhosts.length];
FileInputStream fis;
long Chunk_Size = (fileName.length())/chunks.length;
int cursor = 0;
long fileSize = (long) fileName.length();
int nChunks = 0, read = 0;long readLength = Chunk_Size;
byte[] byteChunk;
try {
fis = new FileInputStream(fileName);
//StupidTest.size = (int)fileName.length();
while (fileSize > 0) {
System.out.println("loop"+ i);
if (fileSize <= Chunk_Size) {
readLength = (int) fileSize;
}
byteChunk = new byte[(int)readLength];
read = fis.read(byteChunk, 0, (int)readLength);
fileSize -= read;
// cursor += read;
assert(read==byteChunk.length);
long aid = fileid;
aid = aid<<32 | nChunks;
chunks[i] = new DataUnit(byteChunk,aid);
// Lister.add(chunks[i]);
nChunks++;
++i;
}
fis.close();
fis = null;
}catch(Exception e){
System.out.println("File splitting exception");
e.printStackTrace();
}
return chunks;
}
chunks[i] = new DataUnit(byteChunk,aid);
sendChunkToClient(new DataUnit(byteChunk, aid));
byteChunk = new byte[(int)readLength];
int len = (int)readLength;随着文件大小的增加，读取整个文件肯定会触发 OutOfMemoryError。调整 -Xmx1024M 可能有利于临时修复，但它绝对不是正确/可扩展的解决方案。此外，无论您如何移动变量(例如在循环外而不是循环内创建缓冲区)，您迟早都会得到 OutOfMemoryError。不为您获取 OutOfMemoryError 的唯一方法是不读取内存中的完整文件。
如果您必须只使用内存，那么一种方法是将块发送到客户端，这样您就不必将所有块都保存在内存中：
而不是：
public class SplitFile {
static int fileid = 0 ;
public static DataUnit[] getUpdatableDataCode(File fileName) throws FileNotFoundException, IOException{
int i = 0;
DataUnit[] chunks = new DataUnit[UAProtocolServer.singletonServer.cloudhosts.length];
FileInputStream fis;
long Chunk_Size = (fileName.length())/chunks.length;
int cursor = 0;
long fileSize = (long) fileName.length();
int nChunks = 0, read = 0;long readLength = Chunk_Size;
byte[] byteChunk;
try {
fis = new FileInputStream(fileName);
//StupidTest.size = (int)fileName.length();
while (fileSize > 0) {
System.out.println("loop"+ i);
if (fileSize <= Chunk_Size) {
readLength = (int) fileSize;
}
byteChunk = new byte[(int)readLength];
read = fis.read(byteChunk, 0, (int)readLength);
fileSize -= read;
// cursor += read;
assert(read==byteChunk.length);
long aid = fileid;
aid = aid<<32 | nChunks;
chunks[i] = new DataUnit(byteChunk,aid);
// Lister.add(chunks[i]);
nChunks++;
++i;
}
fis.close();
fis = null;
}catch(Exception e){
System.out.println("File splitting exception");
e.printStackTrace();
}
return chunks;
}
chunks[i] = new DataUnit(byteChunk,aid);
sendChunkToClient(new DataUnit(byteChunk, aid));
byteChunk = new byte[(int)readLength];
int len = (int)readLength;做：
public class SplitFile {
static int fileid = 0 ;
public static DataUnit[] getUpdatableDataCode(File fileName) throws FileNotFoundException, IOException{
int i = 0;
DataUnit[] chunks = new DataUnit[UAProtocolServer.singletonServer.cloudhosts.length];
FileInputStream fis;
long Chunk_Size = (fileName.length())/chunks.length;
int cursor = 0;
long fileSize = (long) fileName.length();
int nChunks = 0, read = 0;long readLength = Chunk_Size;
byte[] byteChunk;
try {
fis = new FileInputStream(fileName);
//StupidTest.size = (int)fileName.length();
while (fileSize > 0) {
System.out.println("loop"+ i);
if (fileSize <= Chunk_Size) {
readLength = (int) fileSize;
}
byteChunk = new byte[(int)readLength];
read = fis.read(byteChunk, 0, (int)readLength);
fileSize -= read;
// cursor += read;
assert(read==byteChunk.length);
long aid = fileid;
aid = aid<<32 | nChunks;
chunks[i] = new DataUnit(byteChunk,aid);
// Lister.add(chunks[i]);
nChunks++;
++i;
}
fis.close();
fis = null;
}catch(Exception e){
System.out.println("File splitting exception");
e.printStackTrace();
}
return chunks;
}
chunks[i] = new DataUnit(byteChunk,aid);
sendChunkToClient(new DataUnit(byteChunk, aid));
byteChunk = new byte[(int)readLength];
int len = (int)readLength;但上述解决方案的缺点是，如果在块发送之间发生了一些错误，您可能很难尝试从错误点恢复/恢复。
像 Ross Drew 建议的那样，将块保存到临时文件可能会更好、更可靠。
如何创建
public class SplitFile {
static int fileid = 0 ;
public static DataUnit[] getUpdatableDataCode(File fileName) throws FileNotFoundException, IOException{
int i = 0;
DataUnit[] chunks = new DataUnit[UAProtocolServer.singletonServer.cloudhosts.length];
FileInputStream fis;
long Chunk_Size = (fileName.length())/chunks.length;
int cursor = 0;
long fileSize = (long) fileName.length();
int nChunks = 0, read = 0;long readLength = Chunk_Size;
byte[] byteChunk;
try {
fis = new FileInputStream(fileName);
//StupidTest.size = (int)fileName.length();
while (fileSize > 0) {
System.out.println("loop"+ i);
if (fileSize <= Chunk_Size) {
readLength = (int) fileSize;
}
byteChunk = new byte[(int)readLength];
read = fis.read(byteChunk, 0, (int)readLength);
fileSize -= read;
// cursor += read;
assert(read==byteChunk.length);
long aid = fileid;
aid = aid<<32 | nChunks;
chunks[i] = new DataUnit(byteChunk,aid);
// Lister.add(chunks[i]);
nChunks++;
++i;
}
fis.close();
fis = null;
}catch(Exception e){
System.out.println("File splitting exception");
e.printStackTrace();
}
return chunks;
}
chunks[i] = new DataUnit(byteChunk,aid);
sendChunkToClient(new DataUnit(byteChunk, aid));
byteChunk = new byte[(int)readLength];
int len = (int)readLength;在循环之外，只需重复使用它，而不是一遍又一遍地创建一个字节数组，如果它总是相同的。
或者
您可以将传入的数据写入一个临时文件，而不是维护那个巨大的数组，然后在它全部到达后处理它。
还有
如果你多次将它作为一个 int 使用，你可能也应该将 readLength 设置为循环外的一个 int
public class SplitFile {
static int fileid = 0 ;
public static DataUnit[] getUpdatableDataCode(File fileName) throws FileNotFoundException, IOException{
int i = 0;
DataUnit[] chunks = new DataUnit[UAProtocolServer.singletonServer.cloudhosts.length];
FileInputStream fis;
long Chunk_Size = (fileName.length())/chunks.length;
int cursor = 0;
long fileSize = (long) fileName.length();
int nChunks = 0, read = 0;long readLength = Chunk_Size;
byte[] byteChunk;
try {
fis = new FileInputStream(fileName);
//StupidTest.size = (int)fileName.length();
while (fileSize > 0) {
System.out.println("loop"+ i);
if (fileSize <= Chunk_Size) {
readLength = (int) fileSize;
}
byteChunk = new byte[(int)readLength];
read = fis.read(byteChunk, 0, (int)readLength);
fileSize -= read;
// cursor += read;
assert(read==byteChunk.length);
long aid = fileid;
aid = aid<<32 | nChunks;
chunks[i] = new DataUnit(byteChunk,aid);
// Lister.add(chunks[i]);
nChunks++;
++i;
}
fis.close();
fis = null;
}catch(Exception e){
System.out.println("File splitting exception");
e.printStackTrace();
}
return chunks;
}
chunks[i] = new DataUnit(byteChunk,aid);
sendChunkToClient(new DataUnit(byteChunk, aid));
byteChunk = new byte[(int)readLength];
int len = (int)readLength;而 Chunk_Size 是一个变量，对吧？它应该以小写字母开头。