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http断点续传简单实现(java)

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/* K+Ehj(eF  
**SiteFileFetch.java  :E'38~  
*/ blxH`O!  
package NetFox; sa*]q~ a  
import java.io.*; !L-.bve!  
import java.net.*; UZ&bT'>;9g  
t~XwF(";  
vNi7=3  
public class SiteFileFetch extends Thread { _0^<)OSY  
Y@RPQPmIQ  
{"'W!WT b  
SiteInfoBean siteInfoBean = null; //文件信息Bean MT;<\T  
long[] nStartPos; //开始位置 ToDN^qE+  
long[] nEndPos; //结束位置 U*v//@WbH  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g"xLS}Al  
long nFileLength; //文件长度 a*74FVZo.;  
boolean bFirst = true; //是否第一次取文件 [-1Nn}  
boolean bStop = false; //停止标志 >MS}7Hk\  
File tmpFile; //文件下载的临时信息 :NS;y-{^^y  
DataOutputStream output; //输出到文件的输出流 ,GZ(>|  
op&,&  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) L{'qZ#N[  
public SiteFileFetch(SiteInfoBean bean) throws IOException tSE6m-  
{ &RpQ2*4n  
siteInfoBean = bean; 6"eGd"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); KdYT5VUM/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1wqCoDgkp  
if(tmpFile.exists ()) p!U#53  
{ c3i|q@ k  
bFirst = false; M)Tv(7  
read_nPos(); qs 52)$  
} W"VN2  
else Yca9G?^\v  
{ n4(w?,w }  
nStartPos = new long[bean.getNSplitter()]; lb`P9mbr+  
nEndPos = new long[bean.getNSplitter()]; 8p>%}LX/  
} ,N <;!6e  
)Qb1$%r.  
DT n=WGm)  
Nki18ud#  
} VXR.2C  
{eqUEdC  
z=BX-)  
public void run() = J).(E89  
{ ^7F!>!9Ca  
//获得文件长度 k$k (g  
//分割文件 (3c,;koRR  
//实例FileSplitterFetch :[|`&_D9J  
//启动FileSplitterFetch线程 wToz{!n  
//等待子线程返回 XV). cW|.a  
try{ =u${2=  
if(bFirst) bN<c5  
{ m$pXe<  
nFileLength = getFileSize(); 3`IDm5  
if(nFileLength == -1) mL18FR N  
{ 91mXvQ:u  
System.err.println("File Length is not known!"); Nz*qz"T  
} ) 8st  
else if(nFileLength == -2) Uu>YE0/)  
{ ~W%A8`9  
System.err.println("File is not access!"); 8T$:^HW  
} OtY.s\m y  
else p^5B_r:  
{ X[h=UlF  
for(int i=0;i<nStartPos.length;i++) V1xpJ  
{ q6\z]8)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); v-42_}  
} |K aXek  
for(int i=0;i<nEndPos.length-1;i++) s-k~_C>Fw  
{ #s(B,`?N  
nEndPos = nStartPos[i+1]; ]rZ"5y  
} rTDx|pvYx  
nEndPos[nEndPos.length-1] = nFileLength; s:jr/ j!  
} u;h9Ra1  
} = Ky1v$<  
P.&,nFIg3  
g3e\'B'  
//启动子线程 3ZC to[Y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (^eE8j/K  
for(int i=0;i<nStartPos.length;i++) oopTo51,a  
{ %DgU  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ib/&8)Y+J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), VskyRxfdW3  
nStartPos,nEndPos,i); e9k}n\t3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rM=Q.By+\  
fileSplitterFetch.start(); sDA&U9;  
} EUZ#o\6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p2s*'dab7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <RH2G   
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", h8OmO5/H  
nEndPos = " + nFileLength); jI:5[. Y  
// fileSplitterFetch[nPos.length-1].start(); uf4C+ci  
s @\UZ C  
'}3@D$YiM%  
//等待子线程结束 y^pzqv  
//int count = 0; qXC>D Gy  
//是否结束while循环 iv@ey-,<  
boolean breakWhile = false; VA{2a7]  
x aiA2  
+ q@kRQY;n  
while(!bStop) ~Iw7Xq E2  
{ GR6BpV7  
write_nPos(); h^QicvZ  
Utility.sleep(500); {Yp>h5nwM_  
breakWhile = true; ^W}(]jL  
B+W 4r9#  
}s i{  
for(int i=0;i<nStartPos.length;i++) 'Bul_D4B  
{ x%<oeM3U  
if(!fileSplitterFetch.bDownOver) `>.^/SGu>?  
{ rGNYu\\  
breakWhile = false; Nn`l+WA3  
break; 6bv~E.  
} G[;GP0\N  
} _zuaImJ0o  
if(breakWhile) ](^$5Am  
break; U%<E9G594  
?W6qwm,?L  
!xqy6%p  
//count++; 5uo?KSX%  
//if(count>4) q?&Ap*  
// siteStop(); c8@zpkMj/  
} D'F j"&LK  
\3WF-!xe  
nM=5L:d  
System.err.println("文件下载结束!"); w)nFH)f  
} @pV~Q2%  
catch(Exception e){e.printStackTrace ();} vZ&{   
} *6C ]CS  
?j'Nx_RoX  
%ZKP d8  
//获得文件长度 [Yi;k,F:  
public long getFileSize() &d%0[Ui`  
{ fV "gL(7  
int nFileLength = -1; y TbOBl  
try{ [|5gw3 y  
URL url = new URL(siteInfoBean.getSSiteURL()); Ro2Ab^rQ|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6bE~m<B\`  
httpConnection.setRequestProperty("User-Agent","NetFox"); O4+a[82  
uQ(C,f[6p  
dcn/|"jr  
int responseCode=httpConnection.getResponseCode(); g"KH~bN  
if(responseCode>=400) :l;SG=scx  
{ 0 %W0vTvL  
processErrorCode(responseCode); @5=2+ M  
return -2; //-2 represent access is error WDF;`o*3  
} |/YwMBi  
e`7dRnx&0  
E!s?amM4  
String sHeader; q r<+@Q  
`[(.Q  
dlf nhf  
for(int i=1;;i++) ;_nV*G.y#^  
{ xQ]^wT.Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); N!Q~?/!d  
//Utility.log(in.readLine()); !vY5X2?tr,  
sHeader=httpConnection.getHeaderFieldKey(i); myvn@OsEw  
if(sHeader!=null) m"|AD/2;(  
{ (Qp53g  
if(sHeader.equals("Content-Length")) (+x!wX( x  
{ ExW3LM9(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .1q4Q\B<  
break; |PaVb4j  
} .S6u{B  
} Cvgk67C=$  
else +gh*n,:|  
break; V|q`KOF  
} F8* zG 4/&  
} + 2j]  
catch(IOException e){e.printStackTrace ();} Be4n\c.  
catch(Exception e){e.printStackTrace ();} x3C^S~  
V.?Oly  
&f"kWOe$X  
Utility.log(nFileLength); ';J><z{>  
fEYo<@5c]  
k0>]7t$L  
return nFileLength; Z&M fE0F/B  
} {{+woL'C  
iqAME%m  
VYAz0H1-_  
//保存下载信息(文件指针位置) 92pl#Igt  
private void write_nPos() F8En )#  
{ +=JJ=F)  
try{ t$k$ Hd';  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z'r B_l  
output.writeInt(nStartPos.length); =L F9im  
for(int i=0;i<nStartPos.length;i++) ]4 q6N  
{ p J#<e  
// output.writeLong(nPos); # ZcFxB6)  
output.writeLong(fileSplitterFetch.nStartPos); >SSRwYIN  
output.writeLong(fileSplitterFetch.nEndPos); 9?i~4&EY  
} meM61ue_2  
output.close(); )m4O7'2G  
} 9+"\7MHw  
catch(IOException e){e.printStackTrace ();} W%&'EJ)62  
catch(Exception e){e.printStackTrace ();} 5IfyD ]<  
} Xb/^n .>  
qR>"r"Fq  
h}@)oSX }  
//读取保存的下载信息(文件指针位置) nApkK1?  
private void read_nPos() ^a?H "  
{ \UR/tlw+/  
try{ cUPC8k.1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .V'=z|   
int nCount = input.readInt(); LI/;`Y=  
nStartPos = new long[nCount]; #nS[]UbwZ  
nEndPos = new long[nCount]; xZpGSlA  
for(int i=0;i<nStartPos.length;i++) { kF"<W  
{ fD:>cje  
nStartPos = input.readLong(); SPEDN}/^  
nEndPos = input.readLong(); gyx4='Q  
} D/7hVwMw:  
input.close(); ,U?W  
} @w]z"UCwV@  
catch(IOException e){e.printStackTrace ();} Y^(Sc4 W  
catch(Exception e){e.printStackTrace ();} /0J1_g  
} j$K[QSn  
~GWn>  
$YM6}D@  
private void processErrorCode(int nErrorCode) J f,)Y>EI  
{ D3>;X=1  
System.err.println("Error Code : " + nErrorCode); ]-D;t~  
} J}035  
0H6^2T<  
/<Doe SDJ|  
//停止文件下载 nv9kl Q@  
public void siteStop() J"x M[c2  
{ N1LZXXY{  
bStop = true; 7D;g\{>M  
for(int i=0;i<nStartPos.length;i++) ET&Q}UOE  
fileSplitterFetch.splitterStop(); Me[T=Tt`@w  
^EE 3E'  
zr%lBHuW  
} W'6~`t  
}  B\1F  
//负责部分文件的抓取 9VdVom|e  
**FileSplitterFetch.java d paZ6g  
*/ GEXT8f(7  
package NetFox; x(h(a#,r  
|U%S<X  
lq=| =  
import java.io.*; w}^z1n  
import java.net.*; $+)2CXQe5  
-}|GkTM  
|gEA.} pY  
public class FileSplitterFetch extends Thread { I7b(fc-r  
_l]`Og@Y  
3N6U6.Tqb  
String sURL; //File URL q:sDNj)R\  
long nStartPos; //File Snippet Start Position l=*^FK]L`  
long nEndPos; //File Snippet End Position v<bq1QG  
int nThreadID; //Thread's ID X&DuX %x0  
boolean bDownOver = false; //Downing is over ^57[&{MuBF  
boolean bStop = false; //Stop identical j{N;2#.u  
FileAccessI fileAccessI = null; //File Access interface p.i$[6M  
Y'"2s~_ Z  
@OAX#iQl  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException U~Aw=h5SD  
{ awuUaE  
this.sURL = sURL; _H@s^g  
this.nStartPos = nStart; ~J!a?]  
this.nEndPos = nEnd; ,pir,Eozg  
nThreadID = id; %lNWaA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mtuq  
} W+PAlsOC  
ZV}BDwOFI  
V[,/Hw~d%  
public void run() XP5q4BM  
{ @8C^[fDL  
while(nStartPos < nEndPos && !bStop) (u85$_C  
{ _v4TyJ  
^ cN-   
Q_/{TE/sO5  
try{ =wK3\rG  
URL url = new URL(sURL); ;&e5.K+.Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kac@yQD  
httpConnection.setRequestProperty("User-Agent","NetFox"); tp$NT.z  
String sProperty = "bytes="+nStartPos+"-"; 3?Y%|ZVM  
httpConnection.setRequestProperty("RANGE",sProperty); _6THyj$f  
Utility.log(sProperty); C.@R#a'  
 1JgnuBX"  
VY<v?Of i-  
InputStream input = httpConnection.getInputStream(); CU6rw+Vax  
//logResponseHead(httpConnection); C]*9:lK  
&9PzBc  
]tH/87qJ  
byte[] b = new byte[1024]; gqNd@tYI  
int nRead; }txHuq1Q.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #!h:w  
{ 'mpY2|]\$  
nStartPos += fileAccessI.write(b,0,nRead); #^<7VS!x  
//if(nThreadID == 1) kxoJL6IC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EiI3$y3;  
} K>Fo+f  
Lcplc"C  
UBpYR> <\  
Utility.log("Thread " + nThreadID + " is over!"); ywmx6q4MFL  
bDownOver = true; eznw05U  
//nPos = fileAccessI.write (b,0,nRead); V!c{%zd  
} vuuID24:  
catch(Exception e){e.printStackTrace ();} 1mL--m'r  
} ?A(=%c|,g  
} z1f~:AdL  
tb AN{pX  
go6Hb>  
//打印回应的头信息 N_$ X4.7p  
public void logResponseHead(HttpURLConnection con) Sl^HMO  
{ Y1{6lhxgE  
for(int i=1;;i++) 6 )0$UW  
{ g Gg8O? Z  
String header=con.getHeaderFieldKey(i); ^O#,%>1J  
if(header!=null) x_v pds  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); eN>=x40  
Utility.log(header+" : "+con.getHeaderField(header)); N-3w)23*:  
else %whPTc0P  
break; 7\JRHw  
} 9g J`H'  
} PAH; +  
kbN2dL  
4@u*#Bp`|  
public void splitterStop() 7ykpDl^@  
{ yS0!#AG  
bStop = true; U,gg@!1GJo  
} ey_3ah3x  
K63OjR >H  
Ovxs+mQ  
} J2f}{!b+I  
C?fd.2#U  
t3}>5cAxy  
/* o+*YX!]#L  
**FileAccess.java H{x'I@+  
*//文件访问(定位,写) 5V':3o;D__  
package NetFox; }R=n!Y$F  
import java.io.*; -,)&?S  
jdiH9]&U  
0Dv r:]R  
public class FileAccessI implements Serializable{ uZL,+Ce|  
6!sC  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 CBN,~wzP*  
RandomAccessFile oSavedFile; ~2PD%+e7]  
long nPos; w j !YYBH  
wW EnAW~  
rE$0a-d2B  
public FileAccessI() throws IOException & Xm !i(i  
{ }$i Kz*nx|  
this("",0); \f\ CK@  
} O_OgTa  
w%~UuJ#i  
v7gs $'Q  
public FileAccessI(String sName,long nPos) throws IOException !k@ (}CN_*  
{ I!1|);li  
oSavedFile = new RandomAccessFile(sName,"rw"); +-~8t^  
this.nPos = nPos; K G<. s<  
oSavedFile.seek(nPos); /|Z_Dy  
} !xcLJ5^W  
'tvX.aX2  
gr1NcHu  
public synchronized int write(byte[] b,int nStart,int nLen) q>|&u  
{ uJ-Q]yQ  
int n = -1; g?B4b7II  
try{ V3D`pt\[x  
oSavedFile.write(b,nStart,nLen); [GQn1ZLc  
n = nLen; lldNIL6B%  
} Gk:tT1  
catch(IOException e) Hq$&rNnq\  
{ wtM1gYl^  
e.printStackTrace (); 8]h~jNku  
} tVQq,_9C  
"`Q &s  
W_.WMbT  
return n; 4j|IG/m  
} IC"Z.'Ph  
.n[;H;  
Th_PmkvC  
} }fO+b5U  
s!<RWy+  
QL]e<2oPJ  
/* (^pIB~.z  
**SiteInfoBean.java 9$k0  
*/ j%+>y;).  
package NetFox; {ty)2  
5(5:5q.A/D  
&R5zt]4d&  
public class SiteInfoBean { Gr-~&pm  
'uC=xG.*}  
@U+#@6  
private String sSiteURL; //Site's URL | |"W=E  
private String sFilePath; //Saved File's Path j)ME%17  
private String sFileName; //Saved File's Name 4mjlat(d  
private int nSplitter; //Count of Splited Downloading File @AtJO>w  
`G0k)eW  
%rlMjF'tG  
public SiteInfoBean() brCXimG&jo  
{//nSplitter的缺省值为5 *8r^!(Kj  
//default value of nSplitter is 5 &V| kv"Wwj  
this("","","",5); cO$xT;kK  
} %oB0@&!mS  
dGglt Y  
e"y-A&|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G2<$to~{  
{ -Ew>3Q  
sSiteURL= sURL; >AFQm  
sFilePath = sPath; C$p012D1  
sFileName = sName; qt(4?_J  
this.nSplitter = nSpiltter; in K]+H]{  
9a[1s|>w-  
A9lw^.  
} yAAV,?:o[  
!Q WNHL  
ClY`2  
public String getSSiteURL() _TLspqi  
{ _aYhW{wW  
return sSiteURL; 6cd!;Ca  
} -oUGmV_  
{yv_Ni*6!  
F?$Vx)HI  
public void setSSiteURL(String value) j,Mbl"P  
{ Qo :vAv  
sSiteURL = value; ]0&X[?  
} gg.]\#3g  
<THw l/a  
43E)ltR=]  
public String getSFilePath() aGBd~y@e  
{ Ypl;jkHP  
return sFilePath; ]isq}Qv~  
} K\wu9z8M  
8o[gzW:Q)U  
De>e`./56  
public void setSFilePath(String value) :-O$rm  
{ u(FOSmNkN  
sFilePath = value; :1Nc6G  
} ZBR^$?nj  
pj<aMh  
qSlo)aP  
public String getSFileName() K>vl o/#!  
{ c]Gs{V]\  
return sFileName; |{(JUXo6K  
} z:Tj0< A'  
)^BZ,e  
1X2|jj  
public void setSFileName(String value)  ZB |s/  
{ ZV:df 6S  
sFileName = value; P>u2""c  
} MM]0}65KG  
50dN~(;p  
JBA{i45x  
public int getNSplitter() :%33m'EV}  
{ "!(@MfjT  
return nSplitter; n|?sNM<J3  
} ~CHcbEWk)W  
-fV\JJ  
P`O`Mw EAf  
public void setNSplitter(int nCount) pGD-K41O]  
{ f+ZOE?"  
nSplitter = nCount; L~e0^X?  
} *g %bdO  
} 'v^shGI%Ht  
_.R]K$U  
aCH;l~+U  
/* a * CXg.i  
**Utility.java k%u fgHl!  
*/ 6HJsIeQ  
package NetFox; o3\^9-jmp  
>Ik%_:CC`  
O"|d~VQ  
public class Utility { j~S=kYrGM  
>);M\,1\I  
B5+Q%)52  
public Utility() bC"h7$3  
{ BMQ4i&kF|  
6AdUlPM  
#@w/S:KbJt  
} oiR9NB&<  
K:qc "Q=C  
//线程睡眠 G;#xcld  
public static void sleep(int nSecond) 3!cenyE  
{ G9xO>Xp^Al  
try{ 8-H:5E 4Y  
Thread.sleep(nSecond); y xT}hMa  
} /qwY/^  
catch(Exception e) Q(Q?L5  
{ v5e*R8/  
e.printStackTrace (); |;(P+Q4lB  
} hT_Q_1,  
} uit.r^8l  
Wi5Dl=  
//日志 X{i>Q_8>  
public static void log(String sMsg) A.7lo  
{ ?IS[2 v$   
System.err.println(sMsg); =_3rc\0  
} z19%!k  
F4"bMN  
thX4-'i  
public static void log(int sMsg) bQ 0Ab"+D  
{ #PPHxh*S  
System.err.println(sMsg); _I3"35a  
} O[L#|_BnEO  
} m~W[,7NE0&  
xe(7q1   
l O*  
/* -vc$I=b;  
**TestMethod.java Hi$N"16A5z  
*/ 9M1DE  
package NetFox; .q:6F*,1M  
8yDsl  
Qi=0[  
public class TestMethod { i| ,}y`C#  
Pk(%=P ,  
(Uu5$q(  
public TestMethod() .!lLj1?p  
{ ///xx/weblogic60b2_win.exe aR@+Qf  
try{ CK|AXz+EN  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'Ox "YE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); n_Y7*3/b-o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }.WO=IZ  
fileFetch.start(); o /1+ }f  
} { ] 0T  
catch(Exception e){e.printStackTrace ();} R-,L"Vv  
2 w! 0$  
" ;T a8  
} :9x]5;ma  
}y J,&N'p  
9jx>&MnWs  
public static void main(String[] args) 3fZoF`<a  
{ pEN`6*  
new TestMethod(); d1t_o2  
} >zw@!1{1  
} saQo]6#  
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