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http断点续传简单实现(java)

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/* A"ApWJ3  
**SiteFileFetch.java ixJ%wnz  
*/ 1HPYW7jk@"  
package NetFox; <e)5$Aj  
import java.io.*; <? h`  
import java.net.*; yCC.j%@  
u6tD5Y  
!5FZxmUup  
public class SiteFileFetch extends Thread { y{{7)G  
Tp-<!^o4  
zPWJ=T@N  
SiteInfoBean siteInfoBean = null; //文件信息Bean % VZ QX_  
long[] nStartPos; //开始位置 A 9\]y%!  
long[] nEndPos; //结束位置 uv>T8(w  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Vm+e%  
long nFileLength; //文件长度 vQK*:IRKK  
boolean bFirst = true; //是否第一次取文件 X=_`$ 0  
boolean bStop = false; //停止标志 V) Oj6nD]  
File tmpFile; //文件下载的临时信息 OZ,%T9vP  
DataOutputStream output; //输出到文件的输出流 !LDuCz -  
tw{V7r~n  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) PH$fDbC8  
public SiteFileFetch(SiteInfoBean bean) throws IOException $d:>(_p=A  
{ "lU%Pm]>  
siteInfoBean = bean; GP|G[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ur*@TIvD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (`nn\)  
if(tmpFile.exists ()) +T\c<lJ9  
{ B{`4"uEb$G  
bFirst = false; ea7l:(C  
read_nPos(); H#zsk*=QD  
} Dl/Jlsd@  
else 7=V s1TVc  
{ ;}/@ar7s3  
nStartPos = new long[bean.getNSplitter()]; "j(?fVx  
nEndPos = new long[bean.getNSplitter()]; r0 mXRZC  
} <]9%Pm#X  
=~7%R.U([e  
Jng,:$sZ  
srX" vF  
} q>JW$8  
AL(YQ )-Cg  
'8O(J7J  
public void run() yDk|ad|  
{  ^##tk  
//获得文件长度 lL6 bIjf  
//分割文件 dM|&Y6  
//实例FileSplitterFetch 7*D*nY4+  
//启动FileSplitterFetch线程 MJxTzQE  
//等待子线程返回 *cNqgw#\qL  
try{ XnBpL6"T`  
if(bFirst) Ry5/O?Q L  
{ `F)Q=  
nFileLength = getFileSize(); <X5'uve  
if(nFileLength == -1)  3)5Gzn  
{ 6L`{oSX!  
System.err.println("File Length is not known!"); wTT_jyH)  
} g`(' k5=  
else if(nFileLength == -2) =SY5E{`4p  
{ aN\ps g  
System.err.println("File is not access!"); yW3X<  
} X[F<sxw  
else XI>|"*-l  
{ #+X|,0p  
for(int i=0;i<nStartPos.length;i++) 2 d%j6D  
{ IIn0w2:i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .Fdqn?c|+  
} Q"2t :  
for(int i=0;i<nEndPos.length-1;i++) F.nJX ZnJ  
{ UD 0v ia  
nEndPos = nStartPos[i+1]; [#}A]1N  
} }4 p3m]   
nEndPos[nEndPos.length-1] = nFileLength; .Vy*p")"  
} Y ;JP r  
} >o\s'i[  
fWr6f`de  
}=d]ke9_  
//启动子线程 +Xa^3 =B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t")+ L{  
for(int i=0;i<nStartPos.length;i++) %&D,|Yl6  
{ Cpyv@+;D  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hJ)>BeH0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7.-g=Rcz  
nStartPos,nEndPos,i); vSu|!Xb]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  pt`^4}  
fileSplitterFetch.start(); K2= `.  
} pI__<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l?_h(Cq<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); '/Y D$*,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", OK=lp4X  
nEndPos = " + nFileLength); 8XwZJ\5  
// fileSplitterFetch[nPos.length-1].start(); "X\|!Mxh  
f^ q0#+k)  
.I6:iB  
//等待子线程结束 }7`HJ>+m)H  
//int count = 0; H<^*V8J 'w  
//是否结束while循环 41pk )8~pt  
boolean breakWhile = false; ]e*Zx;6oi  
yQ^k%hHa  
mPl2y3m%  
while(!bStop) D)yCuw{M:  
{ @ y{i.G  
write_nPos(); %SWtE5HZQq  
Utility.sleep(500); [31vx0$_p  
breakWhile = true; ^qs{Cf$  
)X8?m <cG  
M 5mCG  
for(int i=0;i<nStartPos.length;i++) W%/lBkP  
{ 50s)5G#  
if(!fileSplitterFetch.bDownOver) ^H0`UKE  
{ F4!,8)}  
breakWhile = false; ^uU'Qc4S=  
break; 9t`Z_HwdCb  
} A5d(L4Q]a(  
} [dszz7/L  
if(breakWhile) 3YtFO;-  
break; ;n-)4b]\  
#g.J,L  
mw^Di  
//count++; SUSam/xeg"  
//if(count>4) <"SDU_<xG  
// siteStop(); <tT*.nM\  
} -3YsrcJi  
|sM#nhxK  
(9;qV:0`  
System.err.println("文件下载结束!"); Gi<ik~  
} 6 (:^>@  
catch(Exception e){e.printStackTrace ();} X >i`z  
} Ch`nDIne  
N8$MAW  
9J"Y   
//获得文件长度 r#Pkhut  
public long getFileSize() 410WWR&4_  
{ 8J&K_ JC^  
int nFileLength = -1; m,zZe}oJ  
try{ o_2mSD!  
URL url = new URL(siteInfoBean.getSSiteURL()); }]-SAM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c$<7&{Pb  
httpConnection.setRequestProperty("User-Agent","NetFox"); =r<0l=  
Ri,8rf0u  
owYSR?aG  
int responseCode=httpConnection.getResponseCode(); Y0kDHG  
if(responseCode>=400) *`}4]OGv.  
{ {{FA "NW  
processErrorCode(responseCode); -:O~J#D  
return -2; //-2 represent access is error VrV* -J'  
} NW}kvZ  
nN|zEw]  
n&?]GyQ  
String sHeader; ` ]*KrY  
*{5L*\AZ  
.Yxx   
for(int i=1;;i++) ObDcNq/b!  
{ _$OhV#LKG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #}^ kMD >  
//Utility.log(in.readLine()); Y(>]7  
sHeader=httpConnection.getHeaderFieldKey(i); {.W$<y (j7  
if(sHeader!=null) e`1,jt'  
{ %cM2;a=2  
if(sHeader.equals("Content-Length")) !ul)e;a  
{ Sb&sW?M  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xg'FC/1LD  
break; T=8> 0D^v5  
} b";w\H  
} st;.Po[h  
else Fm\ h883\  
break; !_+LmBd G  
} %ZV a{Nc  
} w!NtN4>  
catch(IOException e){e.printStackTrace ();} ~jd:3ip+!  
catch(Exception e){e.printStackTrace ();} Qp{rAAC:  
>+v)^7c  
oa:GGW4Q  
Utility.log(nFileLength); AT^?PD_  
&i`\`6 q  
=2VM(GtK>  
return nFileLength; Dk#$PjcRE  
} Jo1=C.V`Y  
\ H#zRSbZ  
cw 3JSz9  
//保存下载信息(文件指针位置) "FC;k >m  
private void write_nPos() T-=sC=sS,  
{ q9- =>  
try{ )Cuc ]>SC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j)Z3m @Ii5  
output.writeInt(nStartPos.length); YoD1\a|  
for(int i=0;i<nStartPos.length;i++) cad%:%p  
{ Ez^U1KKOE7  
// output.writeLong(nPos); /*Z ,i&eC  
output.writeLong(fileSplitterFetch.nStartPos); xbex6i"ZE  
output.writeLong(fileSplitterFetch.nEndPos); )j6VROt  
} DUg  
output.close(); ]R^?Pa1Te4  
} }U$Yiv  
catch(IOException e){e.printStackTrace ();}  A_: Bz:  
catch(Exception e){e.printStackTrace ();} YQ>M&lnQ<  
} E<>Ev_5>  
6:i(<7  
#UH|,>W6  
//读取保存的下载信息(文件指针位置) Q!Rknj 2  
private void read_nPos() 3=!\>0;E-  
{ &3VR)Bxn  
try{ o.5w>l!9K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); sL;qC\S  
int nCount = input.readInt(); c ?mCt0Cg  
nStartPos = new long[nCount]; Bb];qYuCO  
nEndPos = new long[nCount]; .bbl-a/ 3  
for(int i=0;i<nStartPos.length;i++) -yt[0  
{ ukV1_QeN [  
nStartPos = input.readLong(); vJkY  
nEndPos = input.readLong(); dBY,&=T4p  
} l -~H Y*  
input.close(); >JVZ@ PV H  
} \D BtU7"v  
catch(IOException e){e.printStackTrace ();} g7k|Ho-W  
catch(Exception e){e.printStackTrace ();} (3C6'Wt  
} 3O<:eS~  
t?9F2rh  
x|l[fdm5  
private void processErrorCode(int nErrorCode) ))}w;w   
{ 1btQ[a6j  
System.err.println("Error Code : " + nErrorCode); oB8u[ !  
} i Xtar;%  
B8z3W9  
=LHE_ AA  
//停止文件下载 q4$zsw  
public void siteStop() sHO6y0P  
{ ml 7]s N(  
bStop = true; EBS04]5ul  
for(int i=0;i<nStartPos.length;i++) $L>tV='  
fileSplitterFetch.splitterStop(); e!*d(lHKos  
0|8c2{9X,  
}6} Gj8Nb  
} 0qSd #jO  
} AE1!u{  
//负责部分文件的抓取 y5>859"h  
**FileSplitterFetch.java Z^9;sb,x  
*/ :(,uaX> {  
package NetFox; ny17(Y =  
vBCQ-l<Ub  
W[A;VOj0$  
import java.io.*; fB[I1Z  
import java.net.*; O<l_2?S1  
M(o?I}  
l)`bm/k]V  
public class FileSplitterFetch extends Thread { j,QeL  
~a&s5E {  
]O s!=rt  
String sURL; //File URL *+h2,Z('a  
long nStartPos; //File Snippet Start Position |cL'4I>b9  
long nEndPos; //File Snippet End Position tF SO"  
int nThreadID; //Thread's ID %..{c#V  
boolean bDownOver = false; //Downing is over H27_T]\  
boolean bStop = false; //Stop identical R[5*]$(b  
FileAccessI fileAccessI = null; //File Access interface A:F*Y%ZW  
\?&P|7N  
6sBS;+C  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h9c54Ux  
{ o~H4<ayy  
this.sURL = sURL; 8D[P*?O  
this.nStartPos = nStart; N ~L3 9  
this.nEndPos = nEnd; 6rMGl zuRo  
nThreadID = id; D]v=/43  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }s{RW<A  
} OOS(YP@b  
tsR\c O~/  
F>E'/r*  
public void run() y/rmxQtP  
{ qsn6i%VH  
while(nStartPos < nEndPos && !bStop) Fy8KZWim  
{ fk,[`n+  
=7ul,  
fb[f >1|  
try{ =ZjF5,@  
URL url = new URL(sURL); x3O$eKy\|5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @U'I_` LL  
httpConnection.setRequestProperty("User-Agent","NetFox"); %CJgJ,pk>  
String sProperty = "bytes="+nStartPos+"-"; TO.?h!  
httpConnection.setRequestProperty("RANGE",sProperty); ~]BxM9  
Utility.log(sProperty); @ae;&  
#p}I 84Q  
eAS~>|N#x  
InputStream input = httpConnection.getInputStream(); ECqcK~h#E  
//logResponseHead(httpConnection); -qz;  
-m)N~>{qS  
AB40WCu]*  
byte[] b = new byte[1024]; 5an#,vCn{  
int nRead; L31B:t^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) PpX=~Of~  
{ 'S\YNLqQ  
nStartPos += fileAccessI.write(b,0,nRead); fgYdKv8  
//if(nThreadID == 1) ST1PSuC~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _x_om#~n  
} EaGh`*"w(7  
5hak'#2  
-S\74hA  
Utility.log("Thread " + nThreadID + " is over!"); Z?|\0GR+`5  
bDownOver = true; rr>*_67-:  
//nPos = fileAccessI.write (b,0,nRead); 1a 4 [w  
} 2[: *0 DV#  
catch(Exception e){e.printStackTrace ();} / 2>\Z(  
} znv2:  
} d-nqV5  
JaP2Q} &B  
X(kyu,w  
//打印回应的头信息 O0Y/y2d  
public void logResponseHead(HttpURLConnection con) )3PQ|r'  
{ xTNWT_d  
for(int i=1;;i++) #n5q$  
{ ?khwupdi  
String header=con.getHeaderFieldKey(i); A$.woE@  
if(header!=null) [xq"[*Evv  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6=a($s!   
Utility.log(header+" : "+con.getHeaderField(header)); 26un=  
else 0@z=0}0Z  
break; w%;Z`Xn&u  
} }@Lbv aa  
} vUh.ev0  
#aUe7~  
6[>UF!.=  
public void splitterStop() zk= 3L} C  
{ T<kyxbjR  
bStop = true; JTB_-J-TU  
} |uVhfD=NG  
!4 `any  
nf?;h!_7  
} Cp(,+ dD  
=o]V!MW  
fM,U|  
/* /Hb'3,jN  
**FileAccess.java '^ "6EF.R  
*//文件访问(定位,写) 3D70`u  
package NetFox; afOb-G$d=  
import java.io.*; v+dt1;  
6U)Lhf\'o  
i2`i5&*  
public class FileAccessI implements Serializable{ 1V(tt{  
; =.VKW%U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 E&r*[;$  
RandomAccessFile oSavedFile; sr,8zKM)  
long nPos; //*>p  
e.9oB<Etp  
m@  b~  
public FileAccessI() throws IOException aY7kl  
{ P [-2^1P"  
this("",0); 5\/h3 i"I  
} j;@7V4'  
l<0 BMwS8  
LQ pUyqR  
public FileAccessI(String sName,long nPos) throws IOException o mstJ9  
{ Ga0= G&/  
oSavedFile = new RandomAccessFile(sName,"rw"); #"% ]1={b  
this.nPos = nPos; jz(}P8  
oSavedFile.seek(nPos); =;Gy"F1 dp  
} "pTyQT9P  
v&oE!s#  
?'uxYeX6  
public synchronized int write(byte[] b,int nStart,int nLen) 2^N 4(  
{ d[;=X.fZ2  
int n = -1;  )TV4OT#  
try{ ma.yI};$  
oSavedFile.write(b,nStart,nLen); ;(M`Wy]2  
n = nLen; vy\;#X!  
} -ZqN~5>j)  
catch(IOException e) *fVs|  
{ ~yz7/?A)TS  
e.printStackTrace (); PW)XDo7  
} vhiP8DQ  
aR30wxW&)  
f;M7y:A8q,  
return n; }wzU<(Rx  
} 7Wub@Mp  
b?`8-g  
b489sa  
} QZ(se  
(5S(CYls  
p\5DW'  
/* O@St^o*A}  
**SiteInfoBean.java 4RYK9=NH  
*/ Mo`7YS-Y  
package NetFox; * Zb-YA  
[|<2BQX  
RGy4p)z*+  
public class SiteInfoBean { }|>mR];  
l?E7'OEF:  
(.Yt| "j  
private String sSiteURL; //Site's URL Q.: SIBP  
private String sFilePath; //Saved File's Path Yy]^_,r  
private String sFileName; //Saved File's Name D/pc)3Ofe  
private int nSplitter; //Count of Splited Downloading File #MYhKySku  
T1yJp$yD"  
qXmkeidb&W  
public SiteInfoBean() $8#zPJR&  
{//nSplitter的缺省值为5 z;`o>Ja2  
//default value of nSplitter is 5 {~7V A  
this("","","",5); KsI[  
} ((L=1]w  
"1P8[  
#:"F-3A0  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7+';&2M)n~  
{ c0M=T  
sSiteURL= sURL; afY~Y?PJ<  
sFilePath = sPath; sE7!U|  
sFileName = sName; L ;5uB2  
this.nSplitter = nSpiltter; R /J@XP  
F.ml]k&(m  
n]G!@-z  
} ;QbMVY  
m }I@:s2  
'&4W@lvyz  
public String getSSiteURL() I\J ^@&JE  
{ _IiTB  
return sSiteURL; {p&M(W]  
} *cn,[  
],{b&\  
dbF?#s~u  
public void setSSiteURL(String value) !C>}j* 4  
{ "{-jZdq'  
sSiteURL = value; *{|{T_H:  
} mk#xbvvG  
&t1?=F,]  
A}KRXkB  
public String getSFilePath() e\%emp->  
{ |#^##^cF/  
return sFilePath; |f+|OZY  
} Lk{ES$  
pj?wQ'  
wRu+:<o^.  
public void setSFilePath(String value) sCG[gshq  
{ $oKT-G  
sFilePath = value; r}ZL{uWMW  
} /y/O&`X(  
>R "]{y  
mD @#,B7A  
public String getSFileName() F&? &8.  
{ =8BMCedH|  
return sFileName; $S{B{FK  
} -7^?40A  
KDD_WXGt~  
zFVNb  
public void setSFileName(String value) lt 74`9,f  
{ ()L[l@m  
sFileName = value; [:Kl0m7  
} Q; DN*  
7 ,Tg>,%Q  
% \OG#36  
public int getNSplitter() }c/p+Wo  
{ Uz(Sv:G  
return nSplitter; 6^ UQ{P1;  
} 6;rJIk@Fx=  
z 3RD*3b  
U1zcJ l^  
public void setNSplitter(int nCount) m]t`;lr<  
{ P~Ss\PT  
nSplitter = nCount; 4LY kK/:  
} -yKx"Q9F  
} yhnhORSY;  
6 6S I  
E#'JYz@  
/* zq ;YE  
**Utility.java ^~iu),gu  
*/ .{,PC  
package NetFox; yTj!(C  
.Y!] {c  
p'PHBb8I  
public class Utility { aH6{_eY  
]ADj 9  
9I3vW]0x[  
public Utility() ,S.<qmf  
{ @lvvI<U  
Z!\xVCG"q  
8}9B*m  
} &fH;A X.  
tNsiokOm  
//线程睡眠 <\i}zoPO  
public static void sleep(int nSecond) vU5a`0mH  
{ vFuf{ @P  
try{ Z)=S. )  
Thread.sleep(nSecond); ')!+>b(P  
} F$[1KjS  
catch(Exception e) 2flgfB}2k  
{ )3h%2C1uM  
e.printStackTrace (); M'Fa[n*b?!  
} 3Yu1ZuIR  
} A6D.bJ)  
_^{!`*S  
//日志 p6=L}L  
public static void log(String sMsg) =3KK/[2M  
{ .9r+LA{  
System.err.println(sMsg); ;IklS*p]  
} V5 $J  
Ur^~fW1 o  
cb ICO  
public static void log(int sMsg) +n#(QOz  
{ %Ot2bhK;  
System.err.println(sMsg); IB~`Ht8 b  
} uL`6}0  
} >e F4YZ"  
\1k(4MWd  
v]`}T/n  
/* VU~ R  
**TestMethod.java @y3u'Y,B  
*/ AawK/tfs  
package NetFox;  U~%V;*|4  
EbTjBq  
i:8g3|JfMe  
public class TestMethod { gDY+'6m;  
p72:oX\Q I  
/`d|W$vN  
public TestMethod() ARcPHV<(2  
{ ///xx/weblogic60b2_win.exe A\{dq:  
try{ L`$m<9w'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2L=+z1%I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6O|B'?]Pf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); hN(sz  
fileFetch.start();  p1zT]  
} <>!Y[Xr^  
catch(Exception e){e.printStackTrace ();} 8&q|*/2  
&hciv\YT2W  
<Q-Y$ ^\  
} hYm$Sx(=  
&.1F \/]k  
,k% \f]a  
public static void main(String[] args) p#-;u1-B  
{ 41\r7 BS  
new TestMethod(); j/I^\Ms  
} #g)$m}tv?  
} l`#XB:#U  
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