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http断点续传简单实现(java)

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/* nx!qCgo  
**SiteFileFetch.java -XS+Uv  
*/ &&(4n?   
package NetFox; )@8'k]Glw.  
import java.io.*; .u&&H_ UmE  
import java.net.*; "_ PH"W  
|'V<>v.v  
P?Gd}mdX?m  
public class SiteFileFetch extends Thread { Zd[y+$>  
n9<roH  
8! |.H p  
SiteInfoBean siteInfoBean = null; //文件信息Bean G"T;l"TAt8  
long[] nStartPos; //开始位置 aH5t.x79b  
long[] nEndPos; //结束位置 %5Q7#xU  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <r_P? lZW  
long nFileLength; //文件长度 jQ.>2-;H9  
boolean bFirst = true; //是否第一次取文件 r+{!@`dYi  
boolean bStop = false; //停止标志 .RQXxw  
File tmpFile; //文件下载的临时信息 %KJ"rvi4K  
DataOutputStream output; //输出到文件的输出流 h3UZ|B0=  
x*loACee.  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ;w>3,ub(0  
public SiteFileFetch(SiteInfoBean bean) throws IOException bl:a&<F  
{ zumR(<l  
siteInfoBean = bean; yBYuDfeZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _g^K$+F'}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  m+72C]9  
if(tmpFile.exists ()) $4$?M[  
{ qHC*$v#.V?  
bFirst = false; G:h;C].  
read_nPos(); SxLHFN]  
} ??$i*  
else )9A<fwpN  
{ PK.h E{R  
nStartPos = new long[bean.getNSplitter()]; {Gk}3u/  
nEndPos = new long[bean.getNSplitter()]; %mB!|'K%  
} *'s2 K  
Q ^1#xBd  
GM9]>"#o\  
Zi<Sw  
} w{YtTZp3  
^huBqEs  
m &3HFf  
public void run() Gpxb_}P  
{ ;4S [ba1/  
//获得文件长度 zal3j^  
//分割文件 =XRgT1>e  
//实例FileSplitterFetch Tg <>B  
//启动FileSplitterFetch线程 Yn[EI7D  
//等待子线程返回 B Z\EqB  
try{ T,xVQ4J?  
if(bFirst) Vne. HFXA  
{ "b1R5(Ar  
nFileLength = getFileSize(); RBv=  
if(nFileLength == -1) dp//p)B>  
{ -?%{A%'  
System.err.println("File Length is not known!"); )K\k6HC.  
} qs8K jG@  
else if(nFileLength == -2) Be14$7r  
{ L3G)?rPFC#  
System.err.println("File is not access!"); ( 7Ca\H3$  
} /k3n{ ?$/  
else )qe$rD;N  
{ G5XnGl }Q  
for(int i=0;i<nStartPos.length;i++) gKm~cjCB`~  
{ e u=f-HW]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0\_R|i_`>  
} ~qLhZR\g^  
for(int i=0;i<nEndPos.length-1;i++) *Y^Y  
{ *\~kjZ 3  
nEndPos = nStartPos[i+1]; 66"ZH,335  
} 9%)& }KK|  
nEndPos[nEndPos.length-1] = nFileLength; @=<TA0;LL  
} 6q  xUT  
} z5o9\.y({  
C(%5,|6  
M;RnH##W  
//启动子线程 On96N|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; BorfEv} SN  
for(int i=0;i<nStartPos.length;i++) EH!EyNNb  
{ 2h? r![  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n'ca*E(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $O]E$S${  
nStartPos,nEndPos,i); z_,]fd=o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dXK~ Z:  
fileSplitterFetch.start(); IDk:jO  
} o}^vREO  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yV]-Oa$*s0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %ucmJ-< y#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", * SON>BSF  
nEndPos = " + nFileLength); tL4]6u  
// fileSplitterFetch[nPos.length-1].start(); / jL{JF>I  
[q+ 39  
pvwnza1  
//等待子线程结束 y88}f&z#5  
//int count = 0; "y ,(9_#  
//是否结束while循环 7Hkf7\JY  
boolean breakWhile = false; Xi`U`7?D(=  
[@FeRIu8  
^CZ|ci6bX  
while(!bStop) #y9K-}u  
{ ^[\53\R~  
write_nPos(); Ew,wNR`  
Utility.sleep(500); [,A'  
breakWhile = true; m"m;(T{ v  
h}:5hi Jw  
{R8P $  
for(int i=0;i<nStartPos.length;i++) jeuNTDjeL  
{ .STf  
if(!fileSplitterFetch.bDownOver) Nwu Be:"@  
{ xg5@;p  
breakWhile = false; au}0PnA;  
break; u$/2XO  
} ib=^ tK  
} fF]&{b~wk  
if(breakWhile) Gt%?[  
break; vFvu8*0  
C%7)sLWjJS  
X1z0'gvh  
//count++; ]}Hv,a   
//if(count>4) ^d $e^cU  
// siteStop(); U &k 3  
} Pc ?G^ Xol  
F1[ [fH  
3\l9Sf=M|  
System.err.println("文件下载结束!"); ]~ 8N  
} <.B > LU  
catch(Exception e){e.printStackTrace ();} mt]YY<l  
} wU3ica&[   
5OqsnL_V  
tZBE& :l  
//获得文件长度 UHl/AM> !  
public long getFileSize() t:@A)ip  
{  >33b@)  
int nFileLength = -1; <^c0bY1  
try{ nk,Mo5iqV  
URL url = new URL(siteInfoBean.getSSiteURL()); T`<k4ur  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `e;Sjf<  
httpConnection.setRequestProperty("User-Agent","NetFox"); ZTz(NS EK  
x3F L/^S  
#K*q(ei,7h  
int responseCode=httpConnection.getResponseCode(); QS?9&+JM|  
if(responseCode>=400) mb6?$1j  
{ [goPmVe+  
processErrorCode(responseCode); #"YWz)8  
return -2; //-2 represent access is error -ddatc|  
} x=|@AFI  
{j4:. fD  
w)SxwlW}  
String sHeader; _Ws k3AP  
tJfN6  
bD[W~ku  
for(int i=1;;i++) \ bmboNe  
{ O.f3 (e!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); X?xm1|\  
//Utility.log(in.readLine()); c@{^3V##T  
sHeader=httpConnection.getHeaderFieldKey(i); Vk=<,<BB  
if(sHeader!=null) f5XcBW9E  
{ 0~5}F^8[L  
if(sHeader.equals("Content-Length")) uXa}<=O  
{ R,Uy3N  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @!HMd{r  
break; w|*G`~l09  
} T<,tC"  
} z9c=e46O  
else \Le #+ P  
break; zq>"a&Y,  
} (MU7  
} F?Nk:# V  
catch(IOException e){e.printStackTrace ();} =umS^fJ5`  
catch(Exception e){e.printStackTrace ();} 2*E<G|-F  
Z+Zh;Ms  
%cjav  
Utility.log(nFileLength); l_IX+4(@b|  
D\~$6#B>>  
o6%f%:&  
return nFileLength; MNE)<vw>  
} jl29~^@}1i  
D)$k{v#~  
wpMQ 7:j  
//保存下载信息(文件指针位置) SvrV5X  
private void write_nPos() KAEpFobYo  
{ U.jMK{  
try{ I4ct``Di  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :dc J6  
output.writeInt(nStartPos.length); u3!!_~6,z  
for(int i=0;i<nStartPos.length;i++) G?(:Z=  
{ y`Y}P1y*  
// output.writeLong(nPos); 0 1w/,r  
output.writeLong(fileSplitterFetch.nStartPos); $l"(tB7d  
output.writeLong(fileSplitterFetch.nEndPos); 0tyU%z{RV  
} E&v-(0  
output.close(); 82l";;n4p  
} gvt4'kp  
catch(IOException e){e.printStackTrace ();} 0kEq|k9  
catch(Exception e){e.printStackTrace ();} skArocs  
} RtEkd_2  
l'R`XGT  
88U  
//读取保存的下载信息(文件指针位置) (jMp`4P  
private void read_nPos() }Ec"&  
{ lK@r?w|<M  
try{ '*.};t~;"d  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); : P2;9+v  
int nCount = input.readInt(); ~qxc!k!w4  
nStartPos = new long[nCount]; 2M`Ni&v  
nEndPos = new long[nCount]; ^ZBkt7  
for(int i=0;i<nStartPos.length;i++) m>:ig\  
{ nJw1Sl5  
nStartPos = input.readLong(); l,8| E  
nEndPos = input.readLong(); #r}c<?>Vw  
} (P_+m#  
input.close(); AIo;\35  
} |%9~W^b  
catch(IOException e){e.printStackTrace ();} [a6lE"yr  
catch(Exception e){e.printStackTrace ();} 3F3?be  
} B-zt(HG  
L1+cv;t  
p gi7 JQ  
private void processErrorCode(int nErrorCode) pYQs|5d  
{ sIM`Q%  
System.err.println("Error Code : " + nErrorCode); XRin~wz|S  
} b6VAyTa  
SS-   
}DwXs`M7  
//停止文件下载 Q5ao2-\   
public void siteStop() 4 .qjTR  
{ VW/1[?HG5  
bStop = true; h@8  
for(int i=0;i<nStartPos.length;i++) W`kgYGnFG  
fileSplitterFetch.splitterStop(); .!! yj,bQz  
v]sGdZ(6-  
3M`J.>  
} ea/6$f9^  
} N~YeAe~+  
//负责部分文件的抓取 **[p{R]8o  
**FileSplitterFetch.java b*7i&q'H  
*/ =="SW"vNi  
package NetFox; uEY5&wX`  
,;}RIcvQV  
"b;?2_w:E  
import java.io.*; =cY]cPO  
import java.net.*; n9ih^H  
?,[w6O*  
ujBADDwOg)  
public class FileSplitterFetch extends Thread { lnUy ? 0(  
=n&83MYX  
Pd?YS!+S  
String sURL; //File URL }qg&2M%\  
long nStartPos; //File Snippet Start Position oKiu6=  
long nEndPos; //File Snippet End Position &aU+6'+QXB  
int nThreadID; //Thread's ID 8iB}a\]B  
boolean bDownOver = false; //Downing is over c=CXj3  
boolean bStop = false; //Stop identical OYkd?LN  
FileAccessI fileAccessI = null; //File Access interface !LA#c'  
IuL ]V TY  
u^$ CR  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %8/$CR  
{ x(Z@ R\C-a  
this.sURL = sURL; =>U~ligu  
this.nStartPos = nStart; 7;V5hul  
this.nEndPos = nEnd; "`wq:$R  
nThreadID = id; 2J5dZYW  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8h=XQf6k0  
} c@P,  
dEn hNPeRl  
*BV .zbGm  
public void run() #;)7~69  
{ S3r\)5%;  
while(nStartPos < nEndPos && !bStop) s Y,3  
{ el<nY"c  
rkrt.B  
*9PQJeyR  
try{ g$qh(Z_s  
URL url = new URL(sURL); nK[$ID  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -=Hr|AhE  
httpConnection.setRequestProperty("User-Agent","NetFox"); +( d2hSIF  
String sProperty = "bytes="+nStartPos+"-"; Phczf  
httpConnection.setRequestProperty("RANGE",sProperty); f.{0P-Np  
Utility.log(sProperty); ( KrIMZ  
~kga+H  
= zSrre  
InputStream input = httpConnection.getInputStream(); Ra5cfkH;  
//logResponseHead(httpConnection); WF]:?WE%  
\`^jl  
g|oPRC$I'  
byte[] b = new byte[1024]; C%&7,F7  
int nRead; :>5]A6Wi  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~tWBCq 6  
{ aNz%vbh\  
nStartPos += fileAccessI.write(b,0,nRead); /:DxB00  
//if(nThreadID == 1) b< rM3P;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Lv"83$^S9  
} W~qo `r  
uE2Y n`Ha  
ME(!xI//JZ  
Utility.log("Thread " + nThreadID + " is over!"); fHiCuF  
bDownOver = true; mTt 9 o9E  
//nPos = fileAccessI.write (b,0,nRead); T &1sfS,  
} E_z@\z MB  
catch(Exception e){e.printStackTrace ();} =[$*PTe  
} JmK+#o  
} a;(:iMCi  
>3JOQ;:d8  
DI\^ +P  
//打印回应的头信息 9f "*O j  
public void logResponseHead(HttpURLConnection con) CfAqMH*ip  
{ 0t~--/lA  
for(int i=1;;i++) x8H)m+AW  
{ Hi9]M3Ub  
String header=con.getHeaderFieldKey(i); ;J:YNup  
if(header!=null) p81~Lk*Hz@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); JBqzQ^[n  
Utility.log(header+" : "+con.getHeaderField(header)); j EX([J1  
else ]Vubz54  
break; _^B+Xo@E-  
} &HE8O}<>  
} FR&RIFy  
.F]6uXd  
HZm44y$/  
public void splitterStop() [x&&N*>N  
{ 1Dbe0u  
bStop = true; t :_7 O7  
} wNPZ[V:  
|(/"IS]  
F"q3p4-<>  
} 1)%o:Xy o  
9}4L 8?2  
w-KtxG(  
/* QM IQy  
**FileAccess.java ,Ya&M@^Z  
*//文件访问(定位,写) YC$pT  
package NetFox; e'jR<ln|  
import java.io.*; 2`z+_DA  
E?;W@MJi  
6};Sn/ 8  
public class FileAccessI implements Serializable{ ev; &$Hc  
8E" .y$AW  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 a; "+Py  
RandomAccessFile oSavedFile; 27MgwX NQ  
long nPos; %VdJ<=@  
d+bTRnL  
ZK;HW  
public FileAccessI() throws IOException XhS<GF%  
{ OTRTa{TB  
this("",0); 8z+ CYeV  
} +"C0de|-  
t+&WsCN  
bZ389dSn  
public FileAccessI(String sName,long nPos) throws IOException kqy Y:J  
{ Jlzhn#5c-  
oSavedFile = new RandomAccessFile(sName,"rw"); }/=VnCfU  
this.nPos = nPos; qn<~ LxQ  
oSavedFile.seek(nPos); ^Ab|\ 5^3  
} Oz+>I ^Q  
qvT9d7x  
cgU7)`0j  
public synchronized int write(byte[] b,int nStart,int nLen) Gf"/fpeQx  
{ ''V:+@Toh  
int n = -1; ak'RV*>mT  
try{ ThHK1{87X}  
oSavedFile.write(b,nStart,nLen); M]&9Kg3   
n = nLen; |ey6Czm  
} EZ$m4: {e  
catch(IOException e) iQA f  
{ 4Fnr8 r8W  
e.printStackTrace (); ^@N@ gB  
} fQv^=DI#  
4WNWn#M  
$,R|$0B7  
return n; mtHw!*  
} l<gg5 Zea  
* @oAM,@  
< B'BlqTS  
} 3c6#?<%0`  
\}cEHLq  
|=SaI%%Be  
/* ua2SW(C@  
**SiteInfoBean.java n\d-^ml  
*/ Jo2:0<VL  
package NetFox; s]}P jh8  
fHM<6i<C  
)O_Y(^+ $  
public class SiteInfoBean { :#+VH_%N  
fSSDOH!U,  
+4)Kc9S#  
private String sSiteURL; //Site's URL .i&]VGv  
private String sFilePath; //Saved File's Path 7ZN0_Q s  
private String sFileName; //Saved File's Name R7vO,kZ6Q  
private int nSplitter; //Count of Splited Downloading File )4DF9JpD  
xvb5-tK -  
oas}8A)  
public SiteInfoBean() f 1]1ZOb  
{//nSplitter的缺省值为5 }VyD X14j  
//default value of nSplitter is 5 xFgY#F  
this("","","",5); h_H$+!Nzb  
} CY9`ztO*  
 Qq>M}  
)Wgh5C`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2jA-y!(e  
{ JEj.D=@[  
sSiteURL= sURL; D;m>9{=  
sFilePath = sPath; <D=U=5  
sFileName = sName; uP<tP:  
this.nSplitter = nSpiltter; ZMoN  
q*52|?  
u>d,6 !  
} G/=tC8eX  
]x?`&f8i  
RH~KaV3  
public String getSSiteURL() 06L/i,  
{ S)p1[&" M  
return sSiteURL; 3s"x{mtH  
} A=Dzd/CUO  
I)T]}et  
iku) otUc  
public void setSSiteURL(String value) R0 AVAUG  
{ <w<&,xM  
sSiteURL = value; p"3_u;cN  
} e0qU2  
D&$%JT'3  
dy`K5lC@  
public String getSFilePath() !Yd7&#s  
{ !bRoNP  
return sFilePath; ?X~Keb  
} 94\k++kc  
?o?~Df&  
"1yXOy^2  
public void setSFilePath(String value) n}}$-xl  
{ ?u/RQ 1  
sFilePath = value; 1UT&kD!si  
} gWL'Fl}H  
$0=f9+@5  
:[A>O(  
public String getSFileName() }y;s(4  
{ %9C_p]P*  
return sFileName; .Xqe]cax%  
} F=bX\T7  
*;5P65:u$>  
V]&0"HX2r!  
public void setSFileName(String value) <XDYnWz  
{ &3#19v7/  
sFileName = value; ===M/}r  
} \c(R#*0,  
rI23e[  
/-4rcC  
public int getNSplitter() W!MO }0s  
{ %L,mj  
return nSplitter; L/t'|<m  
} iK%%  
$t}t'uJ  
__O@w.  
public void setNSplitter(int nCount) w7+3?'L  
{ OXAr..  
nSplitter = nCount; AU0pJB'  
} _[SW89zk  
} @|BaZq,g  
Te_%r9P|2  
> yk2  
/* ?%K7IJ%  
**Utility.java VB=$D|Ll  
*/ l3[2b Qx  
package NetFox; U|Z Yoc+](  
2SVBuV/R  
}M*yE]LL;Z  
public class Utility { ZgarxV*  
}RvinF:5  
-q'G]}  
public Utility() X?kw=x{2P  
{ KsVN<eR{  
7.}Vvg#G  
s_:7dD  
} yUd>EnQna  
qJN!L))  
//线程睡眠 Ps<;DE\$f4  
public static void sleep(int nSecond) =cz^g^7  
{ <MdIQ;I8  
try{ oU"!"t  
Thread.sleep(nSecond); ~FCkr&Ky3  
} >JVdL\3  
catch(Exception e) ~$w9L998+  
{ zp.-=)D4e  
e.printStackTrace (); # O<,  
} ; D'6sd"  
} $DS|jnpV  
meJ%mY  
//日志 Pnl+.?  
public static void log(String sMsg) xs?Ska,N  
{ rlMahY"C  
System.err.println(sMsg); we?# Dui  
} ,v\^efc:%  
|f67aN  
x#)CH}J  
public static void log(int sMsg) m!#'4  
{ skeH~-`M@  
System.err.println(sMsg); 9fQ[:Hl"  
} I.dS-)Y  
} !pT i.3  
 VB&` S+-  
[a201I0 -  
/* o|`%>&jP  
**TestMethod.java C!X"0]@FA  
*/ "($"T v2  
package NetFox; -HQ(t  
hlKM4JT\  
@{V bu  
public class TestMethod { $@utlIXA'  
y) .dw(  
ag02=}Q'r  
public TestMethod() 2e_m>I  
{ ///xx/weblogic60b2_win.exe  2-$O$&s.  
try{ X^o0t^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -_[ZRf?^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;]vJ[mi~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9u0<$UY%  
fileFetch.start(); Ie"eqO!  
} , ;$SRQ.  
catch(Exception e){e.printStackTrace ();} y <] x  
qe[P'\]L  
H3#rFO"C*  
} W6^YFN  
o$q})!  
Gov]^?^D-  
public static void main(String[] args) [x[ nTIg  
{ ;)Fc@OXN>  
new TestMethod(); W @ ?*~  
} y?P4EVknM3  
} XP%/*am  
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