import java.io.*;
class DownThread extends Thread {
//定义字节数组（取水的竹筒）的长度
private final int BUFF_LEN = 32;
//定义读取的起始点
private long start;
//定义读取的结束点
private long end;
//读取文件对应的输入流
private InputStream is;
//将读取到的字节输出到raf中
private RandomAccessFile raf;
//构造器，传入输入流，输出流和读取起始点、结束点
public DownThread(long start, long end, InputStream is, RandomAccessFile raf) {
//输出该线程负责读取的字节位置
System.out.println(start + "---->" + end);
this.start = start;
this.end = end;
this.is = is;
this.raf = raf;
}
public void run() {
try {
is.skip(start);
raf.seek(start);
//定义读取输入流内容的的缓存数组（竹筒）
byte[] buff = new byte[BUFF_LEN];
//本线程负责读取文件的大小
long contentLen = end - start;
//定义最多需要读取几次就可以完成本线程的读取
long times = contentLen / BUFF_LEN + 4;
//实际读取的字节数
int hasRead = 0;
for (int i = 0; i < times; i++) {
hasRead = is.read(buff);
//如果读取的字节数小于0，则退出循环！
if (hasRead < 0) {
break;
}
raf.write(buff, 0, hasRead);
}
} catch (Exception ex) {
ex.printStackTrace();
}
//使用finally块来关闭当前线程的输入流、输出流
finally {
try {
if (is != null) {
is.close();
}
if (raf != null) {
raf.close();
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
}
public class MutilDown {
public static void main(String[] args) {
final int DOWN_THREAD_NUM = 4;
final String OUT_FILE_NAME = "d:/copy勇敢的心.rmvb";
InputStream[] isArr = new InputStream[DOWN_THREAD_NUM];
RandomAccessFile[] outArr = new RandomAccessFile[DOWN_THREAD_NUM];
try {
isArr[0] = new FileInputStream("d:/勇敢的心.rmvb");
long fileLen = getFileLength(new File("d:/勇敢的心.rmvb"));
System.out.println("文件的大小" + fileLen);
//以输出文件名创建第一个RandomAccessFile输出流
outArr[0] = new RandomAccessFile(OUT_FILE_NAME, "rw");
//创建一个与文件相同大小的空文件
for (int i = 0; i < fileLen; i++) {
outArr[0].write(0);
}
//每线程应该读取的字节数
long numPerThred = fileLen / DOWN_THREAD_NUM;
//整个文件整除后剩下的余数
long left = fileLen % DOWN_THREAD_NUM;
for (int i = 0; i < DOWN_THREAD_NUM; i++) {
//为每个线程打开一个输入流、一个RandomAccessFile对象，
//让每个线程分别负责读取文件的不同部分。
if (i != 0) {
isArr[i] = new FileInputStream("d:/勇敢的心.rmvb");
//以指定输出文件创建多个RandomAccessFile对象
outArr[i] = new RandomAccessFile(OUT_FILE_NAME, "rw");
}
if (i == DOWN_THREAD_NUM - 1) {
//最后一个线程读取指定numPerThred+left个字节
new DownThread(i * numPerThred, (i + 1) * numPerThred
+ left, isArr[i], outArr[i]).start();
} else {
//每个线程负责读取一定的numPerThred个字节
new DownThread(i * numPerThred, (i + 1) * numPerThred,
isArr[i], outArr[i]).start();
}
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
public static long getFileLength(File file) {
long length = 0;
//获取文件的长度
long size = file.length();
length = size;
return length;
}
}
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//com.opensymphony.xwork2.interceptor.ParametersInterceptor.java
//主要代码如下：
//...
@Override
public String doIntercept(ActionInvocation invocation) throws Exception {
Object action = invocation.getAction();
if (!(action instanceof NoParameters)) {
ActionContext ac = invocation.getInvocationContext();
final Map<String, Object> parameters = retrieveParameters(ac);
if (LOG.isDebugEnabled()) {
LOG.debug("Setting params " + getParameterLogMap(parameters));
}
if (parameters != null) {
Map<String, Object> contextMap = ac.getContextMap();
try {
ReflectionContextState.setCreatingNullObjects(contextMap, true);
ReflectionContextState.setDenyMethodExecution(contextMap, true);
ReflectionContextState.setReportingConversionErrors(contextMap, true);
ValueStack stack = ac.getValueStack();
setParameters(action, stack, parameters);
} finally {
ReflectionContextState.setCreatingNullObjects(contextMap, false);
ReflectionContextState.setDenyMethodExecution(contextMap, false);
ReflectionContextState.setReportingConversionErrors(contextMap, false);
}
}
}
return invocation.invoke();
}
protected void setParameters(Object action, ValueStack stack, final Map<String, Object> parameters) {
ParameterNameAware parameterNameAware = (action instanceof ParameterNameAware)
? (ParameterNameAware) action : null;
Map<String, Object> params;
Map<String, Object> acceptableParameters;
if (ordered) {
params = new TreeMap<String, Object>(getOrderedComparator());
acceptableParameters = new TreeMap<String, Object>(getOrderedComparator());
params.putAll(parameters);
} else {
params = new TreeMap<String, Object>(parameters);
acceptableParameters = new TreeMap<String, Object>();
}
for (Map.Entry<String, Object> entry : params.entrySet()) {
String name = entry.getKey();
boolean acceptableName = acceptableName(name)
&& (parameterNameAware == null
|| parameterNameAware.acceptableParameterName(name));
if (acceptableName) {
acceptableParameters.put(name, entry.getValue());
}
}
ValueStack newStack = valueStackFactory.createValueStack(stack);
boolean clearableStack = newStack instanceof ClearableValueStack;
if (clearableStack) {
//if the stack's context can be cleared, do that to prevent OGNL
//from having access to objects in the stack, see XW-641
((ClearableValueStack)newStack).clearContextValues();
Map<String, Object> context = newStack.getContext();
ReflectionContextState.setCreatingNullObjects(context, true);
ReflectionContextState.setDenyMethodExecution(context, true);
ReflectionContextState.setReportingConversionErrors(context, true);
//keep locale from original context
context.put(ActionContext.LOCALE, stack.getContext().get(ActionContext.LOCALE));
}
boolean memberAccessStack = newStack instanceof MemberAccessValueStack;
if (memberAccessStack) {
//block or allow access to properties
//see WW-2761 for more details
MemberAccessValueStack accessValueStack = (MemberAccessValueStack) newStack;
accessValueStack.setAcceptProperties(acceptParams);
accessValueStack.setExcludeProperties(excludeParams);
}
for (Map.Entry<String, Object> entry : acceptableParameters.entrySet()) {
String name = entry.getKey();
Object value = entry.getValue();
try {
newStack.setParameter(name, value);
} catch (RuntimeException e) {
if (devMode) {
String developerNotification = LocalizedTextUtil.findText(ParametersInterceptor.class, "devmode.notification", ActionContext.getContext().getLocale(), "Developer Notification:\n{0}", new Object[]{
"Unexpected Exception caught setting '" + name + "' on '" + action.getClass() + ": " + e.getMessage()
});
LOG.error(developerNotification);
if (action instanceof ValidationAware) {
((ValidationAware) action).addActionMessage(developerNotification);
}
}
}
}
if (clearableStack && (stack.getContext() != null) && (newStack.getContext() != null))
stack.getContext().put(ActionContext.CONVERSION_ERRORS, newStack.getContext().get(ActionContext.CONVERSION_ERRORS));
addParametersToContext(ActionContext.getContext(), acceptableParameters);
}
//...
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