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http断点续传简单实现(java)

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/* PUo&>  
**SiteFileFetch.java  X;g|-<  
*/ Q&;qFv5-l  
package NetFox; Q:=/d$*xd  
import java.io.*; k9?+9bExXA  
import java.net.*; 40ZB;j$l  
c *noH[  
arrcHf 4O  
public class SiteFileFetch extends Thread { <:o><f+  
wAPdu y[  
);LwWKa  
SiteInfoBean siteInfoBean = null; //文件信息Bean PUArKBYM-  
long[] nStartPos; //开始位置 1(a\$Di  
long[] nEndPos; //结束位置 {S~$\4vC!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2J <Z4Ap  
long nFileLength; //文件长度 14zzWzKx  
boolean bFirst = true; //是否第一次取文件 ShxX[k  
boolean bStop = false; //停止标志 5eJd$}Lbc  
File tmpFile; //文件下载的临时信息 6Z=H>w  
DataOutputStream output; //输出到文件的输出流 6.=b^6MV  
1j(,VW  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) exvsf|  
public SiteFileFetch(SiteInfoBean bean) throws IOException zt6ep=  
{ aPgG+tu  
siteInfoBean = bean; $Q4b~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RT9@&5>il  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^)I:82"|?  
if(tmpFile.exists ()) d_hcv|%  
{ Aed"J5[a  
bFirst = false; {F[Xe_=#"  
read_nPos(); %m`QnRX?D  
} ij^!TY[0  
else QkAwG[4  
{ 64@s|m*  
nStartPos = new long[bean.getNSplitter()]; r8$TT\?~  
nEndPos = new long[bean.getNSplitter()]; QJ?!_2Ax  
} st>t~a|T  
=uTV\)  
4dAhJjhgD  
}+1oD{  
} x.Y,]wis  
Qa+gtGtJ  
UQ?8dw:E~  
public void run() ?HTwTi 5!)  
{ /|f]L9)2<  
//获得文件长度 e^TF.D?RS  
//分割文件 +V^_ksi\  
//实例FileSplitterFetch 6iC:l%|u  
//启动FileSplitterFetch线程 RCr:2 Iz  
//等待子线程返回 i :72FVo  
try{ 8!fw Xm  
if(bFirst) ,5 ,4Qf7  
{ Tc :`TE=2  
nFileLength = getFileSize(); AJ mzg  
if(nFileLength == -1) :W"ITY(  
{ 2)YLs5>W%  
System.err.println("File Length is not known!"); 5**xU+&  
} xl$ Qw'  
else if(nFileLength == -2) u1l#k60  
{ 3-5lO#&#  
System.err.println("File is not access!"); Heu@{t.[!D  
} xh$[E&2u  
else b;vO`  
{ YzqhFFaj.  
for(int i=0;i<nStartPos.length;i++)  V Euv  
{ D6pk !mS  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z)~ 2{)  
} _JS'~ JO3{  
for(int i=0;i<nEndPos.length-1;i++) $9/r*@bu8d  
{ $}@l l^  
nEndPos = nStartPos[i+1]; Yc}b&  
} \T?O.  
nEndPos[nEndPos.length-1] = nFileLength; ;Xns9  
} tti.-  
} $6N. ykJ  
+]X^bB[  
p*Cbe\  
//启动子线程 U<x3=P  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; RD^o&VXO  
for(int i=0;i<nStartPos.length;i++) 2#!D"F  
{ 3h&s=e!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z)<>d.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  <_~`)t  
nStartPos,nEndPos,i); cl:YN]BK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &x3y.}1  
fileSplitterFetch.start(); 'Tn$lh  
} ]So%/rOvX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Qa=;Elp:[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); })Jp5vv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _]g6 3q  
nEndPos = " + nFileLength); :n=+$Dq  
// fileSplitterFetch[nPos.length-1].start(); R0>L[1o  
'@FKgy;B)-  
BshS@"8r  
//等待子线程结束 XcXd7e  
//int count = 0; 8Vx'sJ>r4  
//是否结束while循环 R= l/EK  
boolean breakWhile = false; .gB*Y!c7  
9ccEF6o0=  
VCIG+Gz  
while(!bStop) DIY WFVh  
{ YG_3@`-<  
write_nPos(); 4s~o   
Utility.sleep(500); 97lwPjq  
breakWhile = true; :3k(=^%G!  
JW$#~"@r  
BmZd,}{  
for(int i=0;i<nStartPos.length;i++) <M=K!k  
{ $d'Gh2IGA  
if(!fileSplitterFetch.bDownOver) <_+8c{G  
{ B N=,>-O%  
breakWhile = false; PQ j_j#0  
break; \K=Jd#9c  
} &Z?uK,8  
} OtJS5A  
if(breakWhile) W;1Hyk  
break; CzgLgh;:T  
0R.@\?bhL  
+ad 2  
//count++; 2 IGAZ%%  
//if(count>4) plca`  
// siteStop(); 4H'9y3dk  
} WVVqH_  
+XsY*$O  
B,676~I  
System.err.println("文件下载结束!"); Wl1%BN0>  
} z~F!zigNAc  
catch(Exception e){e.printStackTrace ();} `'~|DG}a  
} /)|*Vzu  
GB0] |z5  
[mhY_Hmz]  
//获得文件长度 oD.f/hi0|  
public long getFileSize() Fw|5A"9'a'  
{ iS"rMgq  
int nFileLength = -1; x ` $4  
try{ U7OW)tUf  
URL url = new URL(siteInfoBean.getSSiteURL()); ~ 60J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )Aj~ xA  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9s}--_k?F2  
5)}xqE"x  
:Z<-J`  
int responseCode=httpConnection.getResponseCode(); jYU#] |k~  
if(responseCode>=400) VB Ce=<  
{ yCwQ0|  
processErrorCode(responseCode); | #,b1|af  
return -2; //-2 represent access is error +!X^E9ra  
} sGV%O=9?2  
GDk/85cv0$  
X{)M}WO+r  
String sHeader; ydpsPU?wj5  
SgJQH7N  
[;c#LJ/y  
for(int i=1;;i++) [Ga 9^e$Zv  
{ vJYy`k^Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); jvW/M.q4  
//Utility.log(in.readLine()); Od!j+.OY<  
sHeader=httpConnection.getHeaderFieldKey(i); ;yH/GN#O  
if(sHeader!=null) DJeG  
{ b.$Gc!g  
if(sHeader.equals("Content-Length")) =!7yX ;|  
{ {1FY HM^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); vHWw*gg(/E  
break; x ha!.&DO  
} .*8.{n5   
} |[gnWNdR$M  
else |g@1qXO3  
break; MLUq"f~N  
} 1<lLE1fk  
} N j?,'?'O}  
catch(IOException e){e.printStackTrace ();} <#:"vnm$j  
catch(Exception e){e.printStackTrace ();} Y1+f(Q  
WO]dWO6Mm  
__)9JF  
Utility.log(nFileLength); <MY_{o8d  
x }-rAr  
07CGHAxJ`  
return nFileLength; o#G7gzw)  
} &}rh+z  
HdVGkv/  
vQztD _bX%  
//保存下载信息(文件指针位置) )PZ'{S  
private void write_nPos() \s [Uq  
{ k0%4&pU  
try{ UAa2oY&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \07 s'W U  
output.writeInt(nStartPos.length); lepgmQ|oY  
for(int i=0;i<nStartPos.length;i++) >pr{)bp G  
{ X=-pNwO   
// output.writeLong(nPos); 7|\[ipVX:3  
output.writeLong(fileSplitterFetch.nStartPos); 7x`uGmp1  
output.writeLong(fileSplitterFetch.nEndPos); ]ZZ7j  
} BB9Z?}  
output.close(); 4u A ;--j  
} /8lGP! z  
catch(IOException e){e.printStackTrace ();} &`{%0r[UD#  
catch(Exception e){e.printStackTrace ();} W&)O i ZN  
} T5o9pm D  
W%) foJ  
RytQNwv3  
//读取保存的下载信息(文件指针位置) !\^c9Pg|v  
private void read_nPos() db4Ol=  
{ J=5G<  
try{ UEt #;e  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); x-Yt@}6mvl  
int nCount = input.readInt(); 9w(QM-u  
nStartPos = new long[nCount]; KR#Bj?fz-H  
nEndPos = new long[nCount]; p<tj6O  
for(int i=0;i<nStartPos.length;i++) yin"+&<T  
{ TAIcp*)ZM  
nStartPos = input.readLong(); {^5r5GB=*  
nEndPos = input.readLong(); |v:8^C7  
} i e%ZX  
input.close(); $D1Pk  
} *[k7KG2_U  
catch(IOException e){e.printStackTrace ();} _"Y;E  
catch(Exception e){e.printStackTrace ();} (WX,&`a<$  
} dyD =R  
I"y=A7Nq  
Y<I/y  
private void processErrorCode(int nErrorCode) t :sKvJ  
{ hBO I:4u[  
System.err.println("Error Code : " + nErrorCode); &K|<7Efx  
} oe# :EfT  
8 }nA8J  
}r9f}yX9Q  
//停止文件下载 fo^M`a!va0  
public void siteStop() _ z#zF[%  
{ 77.5 _  
bStop = true; 79z(n[^  
for(int i=0;i<nStartPos.length;i++) RV.*_FG  
fileSplitterFetch.splitterStop(); 52,pCyU  
wqK>=Ri_  
[-=PK\ B  
} Rq<T2}K  
} eZk [6H  
//负责部分文件的抓取 Atzp\oO  
**FileSplitterFetch.java dq[j.Nmq  
*/ JY~s-jxa  
package NetFox; /)e&4.6  
x?VX,9;j  
&S]\)&Yt  
import java.io.*; ;a[56W  
import java.net.*; 2(Vm0E  
fYl$$.  
A!x_R {,yH  
public class FileSplitterFetch extends Thread { N yFa2Ihd  
pg;agtI  
ehoDWO]S  
String sURL; //File URL TY],H=  
long nStartPos; //File Snippet Start Position Nj@k|_1  
long nEndPos; //File Snippet End Position 8yF15['  
int nThreadID; //Thread's ID Q+[gGe JUF  
boolean bDownOver = false; //Downing is over z+C>P4c-y&  
boolean bStop = false; //Stop identical HJ:s)As  
FileAccessI fileAccessI = null; //File Access interface >| rID  
_A;jtS)SY  
l%oie1g l  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]Jq1b210  
{ eh&?BP?  
this.sURL = sURL; mTwz&N\  
this.nStartPos = nStart; %e+hM $Q  
this.nEndPos = nEnd; ~6Vs>E4G  
nThreadID = id; b`usRoD{+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 g>CF|Wj  
} C7[_#1Oz  
TwqyQ49  
|)B&-~a+p  
public void run() &gw. &/t  
{ *1$rg?yGf  
while(nStartPos < nEndPos && !bStop) )0 .gW  
{ 6Y>MW 4q  
&&\ h%-Jc  
DvKM[z3j  
try{ hHm &u^xY  
URL url = new URL(sURL); +^iUY%pm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); By]XD~gcP  
httpConnection.setRequestProperty("User-Agent","NetFox"); kOmTji7  
String sProperty = "bytes="+nStartPos+"-"; U@@#f;&  
httpConnection.setRequestProperty("RANGE",sProperty); Nq/,41  
Utility.log(sProperty); NIY0f@1z-  
>2_BL5<S  
|<96H8  
InputStream input = httpConnection.getInputStream(); U}x2,`PI  
//logResponseHead(httpConnection); mVcpYyD|k  
5wmH3g#0  
RFU(wek  
byte[] b = new byte[1024]; YR@@:n'TP  
int nRead; V7G?i\>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :z_D?UQ  
{ EW%%W6O6  
nStartPos += fileAccessI.write(b,0,nRead); L=O,OS+  
//if(nThreadID == 1) ;]D@KxO$dJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #'^!@+)  
} tV<}!~0,*  
3;zJ\a.+  
m"t\@f  
Utility.log("Thread " + nThreadID + " is over!"); ^/47 *vcN5  
bDownOver = true; DN2K4%cM%'  
//nPos = fileAccessI.write (b,0,nRead); >_!pg<{,  
} >pW8K[  
catch(Exception e){e.printStackTrace ();} Am'5|  
} 5)+(McJC  
} AyB-+oTf(  
/pan{.< k  
E3<jH  
//打印回应的头信息 ,B(UkPGT  
public void logResponseHead(HttpURLConnection con) /J]Yj,  
{ T;XEU%:LK  
for(int i=1;;i++) *]nha1!S  
{ 7L|w~l7R~  
String header=con.getHeaderFieldKey(i); pk%I98! Jy  
if(header!=null) TG8QT\0G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); UTGR{>=>  
Utility.log(header+" : "+con.getHeaderField(header)); OkGg4X|9  
else 8  k9(iS  
break; G(~d1%(  
} M=HW2xn  
} "^u  
DmEmv/N=  
&W:Wv,3  
public void splitterStop() c9/w-u~j  
{ *v)JX _  
bStop = true; 7h?PVobe  
} ;{ u{F L  
<"{Lv)4  
nud,ag  
} PwU}<Hrl]  
>d!w&0z>  
O+%Y1=S[WQ  
/* %Qgo0  
**FileAccess.java ^N#kW-i  
*//文件访问(定位,写) 'C)^hj.  
package NetFox; '}dlVf  
import java.io.*; pN6!IxN$  
zhY V M Q  
5gARGA  
public class FileAccessI implements Serializable{ -|B?pR  
%_;q<@9)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \u ?z:mV  
RandomAccessFile oSavedFile; m8,P-m  
long nPos; H_sLviYLu  
{>tgNW>)  
h@=H7oV7k  
public FileAccessI() throws IOException 1dh_"/  
{ d|k6#f-E  
this("",0); BoYWx^VHx^  
} Q%KH^<  
!SEHDRp  
$'btfo4H  
public FileAccessI(String sName,long nPos) throws IOException LbOjKM^-  
{ &>\E >mJ  
oSavedFile = new RandomAccessFile(sName,"rw"); `Jhu&MWg  
this.nPos = nPos; ~z#Faed=a  
oSavedFile.seek(nPos); A ^ $9[_  
} $j0] +vT  
QFU;\H/  
m:5*:Ii.  
public synchronized int write(byte[] b,int nStart,int nLen) 8fFURk  
{ ]b4*`}\  
int n = -1; ftq&<8  
try{ y;<^[  
oSavedFile.write(b,nStart,nLen); XmXp0b7  
n = nLen; ,u^i0uOg  
} zD}dvI}  
catch(IOException e) H>AQlO+J  
{ CT+pkNC  
e.printStackTrace ();  Q<B=m6~  
} P$S>=*`n U  
a9 7A{7I&  
[_*%  
return n; YqX/7b+  
} VFz (U)._  
*i|O!h1St  
NlXHOUw)u  
} x!fvSoHp  
\gaGTc2&  
Ug*:o d  
/* Os' 7h  
**SiteInfoBean.java P9; =O$s  
*/ GV#"2{t j  
package NetFox; EpSVHD:*  
e#JJd=  
/*!K4)$-*2  
public class SiteInfoBean { ,2q LiE>  
)%Z<9k  
o7<pI8\  
private String sSiteURL; //Site's URL rU`#3}s  
private String sFilePath; //Saved File's Path SjV;& 1Z/  
private String sFileName; //Saved File's Name "& 'h\  
private int nSplitter; //Count of Splited Downloading File cdVh_"[  
y3 @R>@$  
M@EML @~  
public SiteInfoBean() \&ra&3o  
{//nSplitter的缺省值为5 hE0 p> R8  
//default value of nSplitter is 5 O`5PX(J1&  
this("","","",5); Sx?IpcPSm  
} jR`q  y<  
}D/0&<1  
++D-,>.  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \L}aTCvG  
{ &+;z`A'|8  
sSiteURL= sURL; RhIRCN9  
sFilePath = sPath; zC #[  
sFileName = sName; dPgN*Bdv  
this.nSplitter = nSpiltter; Jj4!O3\I  
+#7 e?B  
3<sYxA\?w  
} pE<dK.v6  
pe$" nUy|  
8sjAr.iT.  
public String getSSiteURL() F+ qRC_C>O  
{ 1^^<6e  
return sSiteURL; Wcd;B7OH  
} 4^\5]d!  
8gWifx #N  
rdZk2\<  
public void setSSiteURL(String value) )!J0e-T-8O  
{ $K>'aI;|  
sSiteURL = value; &Iv3_T<AF  
} Uu ~BErEC  
{^zieP!  
Y5 e6|b|  
public String getSFilePath() p'z fo!  
{ rKg~H=4x2  
return sFilePath; .si!`?K%[  
} ew -5VL   
N@Pf\D  
XA75tU[#  
public void setSFilePath(String value) 6&/n/g  
{ sT:$:=  
sFilePath = value; ;zVtJG`  
} {#"[h1  
0.C[/u[  
dnt: U!TW@  
public String getSFileName() hAq7v']m  
{ A+v6N>}*  
return sFileName; }tue`">h  
} 60p*$Vqy  
h^o>9s/|/H  
'&?cW#J?  
public void setSFileName(String value) wh8h1I  
{ ZdG?fWWA  
sFileName = value; ?IRp3H  
} 3>;zk#b2  
MQ7d IUs  
bso l>M[<  
public int getNSplitter() =yo?]ZS  
{ M ^gva?{  
return nSplitter; 46`(u"RP  
} zzOc # /  
yg34b}m{  
B>sSl1opI  
public void setNSplitter(int nCount) 0\XG;KA  
{ T= Q"| S]V  
nSplitter = nCount; Mg3>/!  
} 2;X{ZLo  
} b.HfxYt(  
trD-qi  
^W!w~g+  
/* #mu3`,9V  
**Utility.java 2_i/ F)W  
*/ Sh&n DdF"  
package NetFox; 'MZX"t  
?Pg{nlJvq  
PNVYW?l  
public class Utility { anLSD/'4W  
b5WtL+Z  
z+IHt(  
public Utility() O*% 1   
{ 7;0$UYDU*  
\/=w \Tj  
/S9s%scAy  
} e$!01Y$HI  
sXe=4`O  
//线程睡眠 ig G8L  
public static void sleep(int nSecond) Y:UDte[Lb  
{ ErZYPl  
try{ 3%`asCW$  
Thread.sleep(nSecond); +<qmVW^X  
} P]V/<8o.53  
catch(Exception e) YT:])[gVV  
{ q6E8^7RtS@  
e.printStackTrace (); 7bcl^~lY  
} , c3gW2E  
} ^\|Hz\"*  
D9.H<.|36  
//日志 -<e8\Z`  
public static void log(String sMsg) q]PeS~PjF\  
{ gZkjh{rQ  
System.err.println(sMsg); w.v yEU^  
} x-W6W  
E1'| ;}/  
k)l*L1Y4:  
public static void log(int sMsg) B?o ?LI  
{ ~\4`tc  
System.err.println(sMsg); kC : pal  
} A\Ax5eeL  
} ^)-* Ubzz  
P|M#S9^]  
v(Vm:oK,  
/* .4I "[$?Q  
**TestMethod.java *hugQh ]a  
*/ 8Ter]0M&  
package NetFox; Hz A+Oi  
BEU^,r3z  
Hzos$1DJ  
public class TestMethod { Fh)`A5#  
wD9Gl.uQ  
bD*z"e  
public TestMethod() TF0DQP  
{ ///xx/weblogic60b2_win.exe P?QVT;]  
try{ a+wc"RQ |  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,V$PV,G  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); m5Q?g8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); /%O+]#$`0  
fileFetch.start(); ;4E(n  
} F|Y}X|x8Q  
catch(Exception e){e.printStackTrace ();} <qGVOAnz+  
Z]Zs"$q@  
mv%Zh1khn/  
} 'ju  
e-@=QI^,  
o XKH,r  
public static void main(String[] args) ZmT N  
{ s]=bg+v?j  
new TestMethod(); M mihWD02  
} Mv\odf\]  
} pUTC~|j%:  
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