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http断点续传简单实现(java)

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/* Nu@5 kwH  
**SiteFileFetch.java PkTf JQP8  
*/ ?{eY\I  
package NetFox; {J2#eiF  
import java.io.*; R\*)@[y9l  
import java.net.*; f e|g3>/|  
hd5$yU5JQ  
EJ`Q8uz  
public class SiteFileFetch extends Thread { w#&z]O9r  
A#(`9  
RwW$O@0  
SiteInfoBean siteInfoBean = null; //文件信息Bean lkb2?2\+  
long[] nStartPos; //开始位置 W"Z#Fs{n8  
long[] nEndPos; //结束位置 qbb6,DL7J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ll%G!VR  
long nFileLength; //文件长度 I+|uU g5  
boolean bFirst = true; //是否第一次取文件 JdiP>KXV  
boolean bStop = false; //停止标志 C`NmZwL  
File tmpFile; //文件下载的临时信息 xI?0N<'.*q  
DataOutputStream output; //输出到文件的输出流 Nt~x&s  
@ .gPJMA  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) p>q&&;fe  
public SiteFileFetch(SiteInfoBean bean) throws IOException yAG+] r  
{ %G[/H.7s-  
siteInfoBean = bean; T`\]!>eb  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); T#@{G,N  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); zJY']8ah  
if(tmpFile.exists ()) 26.)Ur<F  
{ \lEkfcc  
bFirst = false; 2bLI%gg3  
read_nPos(); _{$fA6C  
} k][h9'  
else a8Uk[^5  
{ Uyk,.*8"  
nStartPos = new long[bean.getNSplitter()]; tuLH}tkNY  
nEndPos = new long[bean.getNSplitter()]; ARF\fF|<2  
} X?/Lz;,&  
Pu;yEh  
Y5Z!og  
@h}`DNaZ^  
} DnFjEP^  
8z}^jTM  
u,o1{% O  
public void run() %(<(Y  
{ f*m[|0qI<X  
//获得文件长度 3v1 7"  
//分割文件 o=_c2m   
//实例FileSplitterFetch zkexei4^<  
//启动FileSplitterFetch线程 yMxTfR  
//等待子线程返回 Z\ )C_p\-  
try{ `/4:I  
if(bFirst) P!e=b-T  
{ P :k+ y$  
nFileLength = getFileSize(); exZLj0kvF  
if(nFileLength == -1) 1e}8LH7  
{ >o/95xk2  
System.err.println("File Length is not known!"); q3h'l,  
} 66\jV6eH7L  
else if(nFileLength == -2) ?S tsH  
{ }x:f%Z5h  
System.err.println("File is not access!"); vzXag*0  
} =Op+v"  
else & mt)d  
{ P@0Y./Ds  
for(int i=0;i<nStartPos.length;i++) JOD/Raq.1k  
{ *Y6xvib9*  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); FTf<c0  
}  {mTytT  
for(int i=0;i<nEndPos.length-1;i++) 8P2 J2IU  
{ :O-1rD  
nEndPos = nStartPos[i+1]; :P+\p=  
} fU+Pn@'  
nEndPos[nEndPos.length-1] = nFileLength; 3BQ!qO17^d  
} -VT+O+9_A  
} 1m@^E:w  
A''pS  
M.[rLJZ4  
//启动子线程  L,LNv  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; xDLG=A%]z  
for(int i=0;i<nStartPos.length;i++) 0-d>I@j  
{ GJA`l8`SQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \Qy$I-Du  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), tTanW2C  
nStartPos,nEndPos,i); v)X\GmW7w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7cTk@Gq  
fileSplitterFetch.start(); rcN 9.1  
} @It>*B yB.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z rfUQO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); '{b1!nC;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =O$M_1lp  
nEndPos = " + nFileLength); u bW]-U=T  
// fileSplitterFetch[nPos.length-1].start(); {XCf-{a]~  
</`yd2>  
r 2:2,5_  
//等待子线程结束 yxWO [ Z  
//int count = 0; Ond'R'3\E  
//是否结束while循环 s Be7"^  
boolean breakWhile = false; ipE ]}0q  
98XVa\|tl  
L=; -x9  
while(!bStop) s>n(`?@L  
{ /~p+j{0L3W  
write_nPos(); p9eRZVy/  
Utility.sleep(500); E%N2k|%8d_  
breakWhile = true; pv)`%<  
4=8QZf0\  
j]rz] k  
for(int i=0;i<nStartPos.length;i++) iEyeX0nm  
{ |I;$M;'r&  
if(!fileSplitterFetch.bDownOver) gb|Q%LS9R  
{ )?! [}t  
breakWhile = false; 5VW|fI  
break; #'baPqdO  
} hsRvr`#m|  
} Y"g.IK`V  
if(breakWhile) E0n6$5Uc?  
break; ^Q<mV*~  
3>M&D20Z  
tz NlJ~E  
//count++; e.d #wyeX  
//if(count>4) ,MPB/j^o5!  
// siteStop(); 7r# ymQ  
} y[};J vk  
`_ %S  
nuQ]8 -,  
System.err.println("文件下载结束!"); I?#85l{>  
} Lo.rvt  
catch(Exception e){e.printStackTrace ();} {y=W6uP  
} DE$q+j0P  
W*DVi_\$y  
w8Q<r.  
//获得文件长度 $lA V6I.  
public long getFileSize() ?tdd3ai>  
{ 38ES($  
int nFileLength = -1; zdl%iop3e  
try{ eYUr-rN+)z  
URL url = new URL(siteInfoBean.getSSiteURL()); `$LWmm#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _9H*agRe  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,QIF &  
^[E' 1$D  
M,5j5<7  
int responseCode=httpConnection.getResponseCode(); C;+(Zp  
if(responseCode>=400) +yob)%  
{ f"u *D,/sS  
processErrorCode(responseCode); eK_*2=;XRW  
return -2; //-2 represent access is error }T^cEfX  
} >Hb^P)3  
mbRq JT>@  
g>0XxjP4  
String sHeader; RgdysyB  
8(g:HR*;  
`nXVE+E@  
for(int i=1;;i++) ?<&O0'Q  
{ jxa D&4Fs8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); YYEJph@06q  
//Utility.log(in.readLine()); >Iewx Gb>  
sHeader=httpConnection.getHeaderFieldKey(i); 9Ya<My  
if(sHeader!=null) nMfFH[I4  
{ ZoB*0H-  
if(sHeader.equals("Content-Length")) c3*t_!@oC  
{ B&+`)E{KB  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $mmup|;(  
break; =p^He!  
} X:a`B(@S  
} v8gdU7Ll,  
else 8[CB>-9  
break; GuZ ( &G6*  
} l.\re"Q  
} {qW~"z*  
catch(IOException e){e.printStackTrace ();} H.<a`m m8  
catch(Exception e){e.printStackTrace ();} l+V,DCE  
FlfI9mm  
- K%,^6  
Utility.log(nFileLength); tkQH\5  
KIA 2"KbjG  
Nw&!}#m  
return nFileLength; !Fw?H3X!"q  
} fP tm0.r  
F/m^?{==~*  
F62V 3 Xy  
//保存下载信息(文件指针位置) F-D]TRG/*]  
private void write_nPos() $@d9<83=  
{ W3vi@kb]  
try{ 72sD0)?A  
output = new DataOutputStream(new FileOutputStream(tmpFile)); g~7Ri-"  
output.writeInt(nStartPos.length); jztq.2-c#  
for(int i=0;i<nStartPos.length;i++) kt[:@Nda9  
{ 4!asT;`'  
// output.writeLong(nPos); LA_3=@2.H  
output.writeLong(fileSplitterFetch.nStartPos); i |{Dd%4vK  
output.writeLong(fileSplitterFetch.nEndPos); Am8x74?  
} aK,z}l(N  
output.close(); VL[R(a6c <  
} JOjoiA  
catch(IOException e){e.printStackTrace ();} 8<mjh0F-,  
catch(Exception e){e.printStackTrace ();} ) xbO6V  
} VIP7OHJh  
mrm^e9*Z  
K.G$]H  
//读取保存的下载信息(文件指针位置) ug{R 3SS  
private void read_nPos() -p-B2?)A  
{ "#v=IJy&r  
try{ ZpUCfS)|&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =fm]Dl9h*  
int nCount = input.readInt(); c4_`Ew^k  
nStartPos = new long[nCount]; Qn ^bVhG+  
nEndPos = new long[nCount]; ?[*0+h`en  
for(int i=0;i<nStartPos.length;i++) > 0{S  
{ Tirux ;  
nStartPos = input.readLong(); x^"E S%*  
nEndPos = input.readLong(); AtR?J"3E  
} %Pksv}  
input.close(); ^Qu iH'  
} :K\mN/ x  
catch(IOException e){e.printStackTrace ();} V\V)<BARe  
catch(Exception e){e.printStackTrace ();} J$~<V IX  
} s >0Nr  
"NRDNqj(  
!*2%"H*  
private void processErrorCode(int nErrorCode) Bl9jkq ]  
{ ZVeaTK4_ t  
System.err.println("Error Code : " + nErrorCode); ;['[?wk  
} kNu'AT#3|  
9Pw0m=4  
JQ :Ri  
//停止文件下载 pZ#ap<|>I  
public void siteStop() mDh1>>K'~  
{ [m+iQVk'  
bStop = true; i{D=l7j|w  
for(int i=0;i<nStartPos.length;i++) ! _2n  
fileSplitterFetch.splitterStop(); X0 -IRJ[  
g*w<*  
-@>BHC  
} nW "q  
} fC}R4f7C  
//负责部分文件的抓取 6h3HDFS7s  
**FileSplitterFetch.java T0)"1D<l  
*/ cI]WrI2CQa  
package NetFox; [![%9'+P  
3:%QB9qc]'  
+i\&6HGK;-  
import java.io.*; %3HVFhl  
import java.net.*; Pmi#TW3X  
v#=`%]mL  
`Q+moX  
public class FileSplitterFetch extends Thread { V|)>{Xdn  
~) ?  
H A}f,),G  
String sURL; //File URL B*htN  
long nStartPos; //File Snippet Start Position eT'nl,e|  
long nEndPos; //File Snippet End Position ::n;VY2&  
int nThreadID; //Thread's ID K;7f?52  
boolean bDownOver = false; //Downing is over jkiTj~WE-  
boolean bStop = false; //Stop identical "uLjIIl  
FileAccessI fileAccessI = null; //File Access interface }FF W|f  
@DW[Z`X  
"o& E2#  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException yGg,$WM  
{ ] 4+s$rG  
this.sURL = sURL; _md=Q$9!m  
this.nStartPos = nStart; A?G IBjs  
this.nEndPos = nEnd; 'gQidf  
nThreadID = id; (h']a!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k7tYa;C  
} * y^OV_n-8  
~}Z\:#U  
Oo?,fw  
public void run() )hwV`2>l  
{ `ovtHl3Q  
while(nStartPos < nEndPos && !bStop) iAY!oZR(WT  
{ hzI *{  
> Oh?%%6  
7\o!HMfK  
try{ %7Kooq(i  
URL url = new URL(sURL); j?b\+rr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ck#"*] ,  
httpConnection.setRequestProperty("User-Agent","NetFox"); UDf9FnG}L  
String sProperty = "bytes="+nStartPos+"-"; 1Xy]D  
httpConnection.setRequestProperty("RANGE",sProperty); Gf8s?l  
Utility.log(sProperty); AvR2_  
^ 4%Zvl  
/8@m<CW2Y  
InputStream input = httpConnection.getInputStream(); 3E}EBJLsZ  
//logResponseHead(httpConnection); DjMf,wX-{  
=1dI>M>tm  
I[o*RKT'"  
byte[] b = new byte[1024]; A5#y?Aq  
int nRead; _eLWQ|6Fx  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) elJ)4Em  
{ (_* wt]"'  
nStartPos += fileAccessI.write(b,0,nRead); P[t$\FS  
//if(nThreadID == 1) 3*DXE9gA9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `,wu}F85  
} F{k+7Ftc  
\(I6_a_{  
7#;vG>]  
Utility.log("Thread " + nThreadID + " is over!"); eT"Uxhs-}  
bDownOver = true; mzL[/B#>M  
//nPos = fileAccessI.write (b,0,nRead); mxrG)n6Y  
} yh;Y,;4  
catch(Exception e){e.printStackTrace ();} rl:KJ\*D  
} oN[Th  
} NTs;FX~g[  
:lcea6iO  
B~r}c4R{7  
//打印回应的头信息 V6iL5&  
public void logResponseHead(HttpURLConnection con) BpAB5=M0  
{ ]/]ju$l9Z  
for(int i=1;;i++) h?@G$%2  
{ .uZ7 -l  
String header=con.getHeaderFieldKey(i); eN0P9.eqM  
if(header!=null) q5 &Ci`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); L^9HH)Jc  
Utility.log(header+" : "+con.getHeaderField(header)); Ru%|}sfd  
else /<)-q-W;  
break; DrS~lTf=>  
} upn8n vy4(  
} T!q_/[i~7  
~HLRfL?  
ph30'"[Z}  
public void splitterStop() _[Gb)/@mM  
{ wV <7pi  
bStop = true; ,-*iCs<  
} 2@@l{Y0f6  
g%J./F=@3  
irxz l3   
} wuK=6RL  
0TE@xqW  
pV`$7^#X  
/* 9$WJ"]  
**FileAccess.java a4GWuozl  
*//文件访问(定位,写) ?_4^le[;  
package NetFox; p]LnE `v  
import java.io.*; ki\uTD`mf  
4be> `d5j  
(}H ,ng'4  
public class FileAccessI implements Serializable{ n`5WXpz4;  
u]vPy ria  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Y^lQX~I2{  
RandomAccessFile oSavedFile; wz#[:2  
long nPos; 2ChWe}f  
=3+L#P=i9  
~@M7&%]  
public FileAccessI() throws IOException xEoip?O?7F  
{ 8GB]95JWwp  
this("",0); MQw9X  
}  v4<j   
8]*Q79  
O k(47nC  
public FileAccessI(String sName,long nPos) throws IOException 3ut_Bt\  
{ PZ]5Hf1"  
oSavedFile = new RandomAccessFile(sName,"rw"); ?MZ:_'2p  
this.nPos = nPos; edN8-P(  
oSavedFile.seek(nPos); qpgU8f  
} *FPg#a+  
`!Ln|_,d  
QWhp:] }  
public synchronized int write(byte[] b,int nStart,int nLen) x`2pr  
{ 6o lV+  
int n = -1; rgR?wXW]jE  
try{ -N^ =@Yx)  
oSavedFile.write(b,nStart,nLen); Sr7@buF  
n = nLen; +{vQS FW  
} /#\?1)jCK  
catch(IOException e) c,BAa*]K  
{ m^0A?jBrR  
e.printStackTrace (); M7 p8^NL  
} eiB(VOJ  
(-2R{! A  
PJwEA  
return n; 6aSM*S)  
} =tq7z =k  
fv|%Ocm  
*^6k[3VY  
} Q0SW;o7  
cUM_ncYOP  
:~r#LRgc  
/* =#'+"+lQ }  
**SiteInfoBean.java W :>J864!  
*/ 0~.)GG%R>D  
package NetFox; z@n+7p`w  
g5<ZS3tQ  
"o<D;lO  
public class SiteInfoBean { hs,5LV)|y  
ZpTi:3>  
{6YxN&  
private String sSiteURL; //Site's URL 9dw0<qw1%  
private String sFilePath; //Saved File's Path PIpWa$b  
private String sFileName; //Saved File's Name &08 Tns"  
private int nSplitter; //Count of Splited Downloading File !xJFr6G~8  
m^Rd Iy)  
X%35XC.n  
public SiteInfoBean() B,:23[v  
{//nSplitter的缺省值为5 %N1T{   
//default value of nSplitter is 5 'iGMn_&  
this("","","",5); R>` ih&,)  
} D~7%};D[  
TA<hj[-8  
@Z,qu2~|!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'H FwP\HX  
{ p0?o<AA%O  
sSiteURL= sURL; &7lk2Q\  
sFilePath = sPath; 0rGj|@+;  
sFileName = sName; mn Qal>0~  
this.nSplitter = nSpiltter; u`nt\OF  
bQ i<0|S  
Kl!DKeF  
} y K=S!7p\  
MQjG<O\  
L>i<dD{  
public String getSSiteURL() TIKEg10I  
{ PlF89-  
return sSiteURL; [Aa[&RX+9  
} \;'_|bu3.  
'"'D.,[W2  
CuF%[9[cT  
public void setSSiteURL(String value) oPp!*$V  
{ k q/t]%(  
sSiteURL = value; !XkymIX~O.  
} c&0;wgieg  
5/zf x  
dw'<"+zO  
public String getSFilePath() 4o)(d=q  
{ j\%?<2dj=  
return sFilePath; #_?426Wfs  
} qr7 X-[&  
_K*\}un2  
N`y}Gs  
public void setSFilePath(String value) <W=~UUsn  
{ {d&X/tT  
sFilePath = value; \9[NH/.Z{  
} ^aGZJiyJ  
G5y]^P  
C.b,]7i  
public String getSFileName() UIC\CP d  
{ 4r68`<mn[  
return sFileName; $]Q*E4(kV9  
} wrZ7Sr!/V  
Gp?ToS2^d  
!$%/ rQ9  
public void setSFileName(String value) $.suu^>^w  
{ +#de8/x  
sFileName = value; 7,) 67G;  
} *qeic e%E  
f}Ne8]U/Hc  
RT8_@8  
public int getNSplitter() XhHel|!g:  
{ s$SU vo1J  
return nSplitter; CF4Oh-f  
} ~#HH;q_7m  
#;qFPj- v  
}a #b$]Y  
public void setNSplitter(int nCount) !q7;{/QM6  
{ J_y<0zF**  
nSplitter = nCount; J]kP`  
} \Y>#^b?  
} i5L+8kx4  
I>YtWY|ed  
! 4qps$p{  
/* =,/A\F  
**Utility.java O]$*EiO\  
*/ hB2s$QS  
package NetFox; LP0;n\  
,N))=/  
BCa90  
public class Utility { :$GL.n-?  
)$9C`d[  
Xj})?{FP  
public Utility() ]|((b/L3  
{  9:K  
: e0R7sj  
c|R3,<Q]  
} [#,X$O>  
i SAidK,  
//线程睡眠 YP .%CD(K  
public static void sleep(int nSecond) Mi %1+  
{ )LMBxyS  
try{ DS[l,x  
Thread.sleep(nSecond); w/^0tZ~  
} 0?&aV_:;X  
catch(Exception e) FgHB1x4;  
{ r=P$iG'&  
e.printStackTrace (); NBbY## w0  
} 8Jib|#!  
} 2'O!~8U  
)l[7;ZIw$  
//日志 1Hk<_no5  
public static void log(String sMsg)  2U+z~  
{ -f|+  
System.err.println(sMsg); x`=5l`  
} 0-&s J  
O+8ApicjTc  
%unK8z  
public static void log(int sMsg) (Aov}I+  
{ &:cTo(C'  
System.err.println(sMsg); Lct+cKKU  
} :;hBq4h  
} 5@%=LPV  
|qudJucV  
zx]M/=7,V#  
/* L[[H&#\  
**TestMethod.java ~i_ R%z:y  
*/ J 1y2Qw$G  
package NetFox; 8L9S^ '  
~]_jKe4W  
m(7_ZiL=  
public class TestMethod { 6Nd_YX  
:R|2z`b!  
!f]3Riw-=,  
public TestMethod() ?H7p6m u  
{ ///xx/weblogic60b2_win.exe  k9VQ6A  
try{  C>K"ZJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0?4^.N n3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); u!EulAl  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0,D9\ Ebd  
fileFetch.start(); ?$8 ,j+&I  
} =B{$U~}  
catch(Exception e){e.printStackTrace ();} &MGgO\|6  
#<V'gE  
@SVEhk#  
} $}h_EI6hS  
WZO 0u  
>5@ 0lYhH  
public static void main(String[] args) T.Y4L  
{ ABYW1K=  
new TestMethod(); kU9AfAe  
} FVLA^$5c  
} "e};?|y  
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