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http断点续传简单实现(java)

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/* $2Y'[Dto\  
**SiteFileFetch.java ~|e?@3_G  
*/ RG [*:ReB9  
package NetFox; \ct)/  
import java.io.*; @= f2\hU  
import java.net.*; ~^((tT  
 LAG*H  
HS3] 8nJW  
public class SiteFileFetch extends Thread { T `x:80  
Tw BwqQ)t  
b/IT8Cm3  
SiteInfoBean siteInfoBean = null; //文件信息Bean km1{Oh  
long[] nStartPos; //开始位置 QR<z%4  
long[] nEndPos; //结束位置 |QwX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \M~M  
long nFileLength; //文件长度 Y! e  
boolean bFirst = true; //是否第一次取文件 0|<ER3xkx  
boolean bStop = false; //停止标志 vzl+0"  
File tmpFile; //文件下载的临时信息 tu}AJ  
DataOutputStream output; //输出到文件的输出流 Ws"eF0,'Z  
 gBQK  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) $\kqh$")  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4fPbwiK j  
{ =h,6/cs  
siteInfoBean = bean; +]^6&MqO  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Pt~mpRl H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); s@^ (1g[w`  
if(tmpFile.exists ()) f/t1@d!  
{ 2P9gS[Ub  
bFirst = false; '\qd{mM\r  
read_nPos(); Vb>!;C  
} dI'cZt~n  
else l:v:f@M&  
{ G}1?lO_d`  
nStartPos = new long[bean.getNSplitter()]; hA1\+r  
nEndPos = new long[bean.getNSplitter()]; {2<A\nW  
} OQ&?^S`8',  
0PIiG-o9  
f`w$KVZ1!w  
EgO=7?(pW  
} Hn"xn79nc  
b0 ))->&2  
))"J  
public void run() s[h& Uv"G  
{ 2 2K:[K  
//获得文件长度  DJ?kQ  
//分割文件 e573UB  
//实例FileSplitterFetch r8\"'4B1  
//启动FileSplitterFetch线程 `9QvokD  
//等待子线程返回 P$z8TDCH  
try{ 6'6 "Ogu%'  
if(bFirst) V?U->0>Z4  
{ "Sp+Q&2U  
nFileLength = getFileSize(); | k"?I  
if(nFileLength == -1) k,o|"9H  
{ CAg\-*P|  
System.err.println("File Length is not known!"); e%#(:L  
} 6x%uWZa'  
else if(nFileLength == -2) bp G`,[  
{ b#%s!  
System.err.println("File is not access!"); ['%]tWT9  
} ?o'!(3`L  
else Bw2-4K\"kc  
{ 6.? Ke8iC  
for(int i=0;i<nStartPos.length;i++) dKyJ.p   
{ MONfA;64/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8z&7wO  
} b e[KNrO  
for(int i=0;i<nEndPos.length-1;i++) ~_C[~-  
{ 90OSe{  
nEndPos = nStartPos[i+1]; t,#9i#q#  
} 2 O\p`,.  
nEndPos[nEndPos.length-1] = nFileLength;  # Vz9j  
} $_s"16s  
} l \~w(8g<A  
k(|D0%#b7  
C.I.f9s?R  
//启动子线程 JjarMJr| D  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #$p&J1   
for(int i=0;i<nStartPos.length;i++) p9w<|ZQ]:  
{  y/t{*a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PLDg'4DMg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nO^aZmSu  
nStartPos,nEndPos,i); >?iL_YTX  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "N'tmzifh  
fileSplitterFetch.start(); f\CJ |tKX  
} a4HUP*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H^ _[IkuA%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4QbDDvRQ^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", L&3Ak}sh  
nEndPos = " + nFileLength); &Rw4ub3  
// fileSplitterFetch[nPos.length-1].start(); p/jC}[$v  
!yAlb#yu  
H8d%_jCr  
//等待子线程结束 *FoH '\=  
//int count = 0; 5o;M  
//是否结束while循环 "~~Js~  
boolean breakWhile = false; A:$Qt%c  
5Ug.J{d  
5~&9/ ALk5  
while(!bStop) X yi[z tN  
{  JvFd2@  
write_nPos(); g?,\bmHE  
Utility.sleep(500); 7b7~D +b  
breakWhile = true; J})G l  
f 7B)iI!  
=0,:w(Sb!  
for(int i=0;i<nStartPos.length;i++) v'`VyXetl  
{ hM~9p{O  
if(!fileSplitterFetch.bDownOver) 2pR+2p`  
{ :o$k(X7a  
breakWhile = false; eSvS<\p  
break; 7x8/Vz@\  
} oujg( ^E  
} Cf@~W)K  
if(breakWhile) Le#>uWM  
break; ,CiN@T \&  
m$^Wyk}  
?wzE+p-  
//count++; )}QtK+Rq  
//if(count>4) x6Q,$B  
// siteStop(); +"1@ 6,M  
} YlfzHeN1  
Jq0aDf f  
H4C]%Q  
System.err.println("文件下载结束!"); ziUEA>m */  
} S<Z]gY @c  
catch(Exception e){e.printStackTrace ();} y;zp*(}f$h  
} 9[yW&t;#  
 ~DYUI#x  
N!R>L{H>  
//获得文件长度 f' |JLhs  
public long getFileSize() TEQs\d  
{ lYz{# UX}  
int nFileLength = -1; VF8pH <  
try{ {%g]Ym=  
URL url = new URL(siteInfoBean.getSSiteURL()); tkT:5O6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zN2CI6  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~qFuS933  
gaFOm9y.e  
+T]/4"^M  
int responseCode=httpConnection.getResponseCode(); M7U:UV)  
if(responseCode>=400) [n%=2*1p  
{ J~.8.]gXW  
processErrorCode(responseCode); Q<4Sd:P`"  
return -2; //-2 represent access is error ^0oOiZs  
} %K0 H?^.  
;2Aqztp  
$oF0[}S  
String sHeader; {8b6M  
(jj=CLe  
sfb)iH|sW  
for(int i=1;;i++) WI@l2`X  
{ }N @8zB~X  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); R@ksYC3 F  
//Utility.log(in.readLine()); l/WQqT  
sHeader=httpConnection.getHeaderFieldKey(i); u7Z-kZ  
if(sHeader!=null) ^FO&GM2a  
{ Er@'X0n  
if(sHeader.equals("Content-Length")) TsiI5'tx  
{ BO5\rRa0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); | ]#PF*  
break; IIj :\?r  
} 2G=prS`s  
} y Skz5K+|g  
else v#/k`x\  
break; l1_hD ,4  
} 6uNWL `v  
} ]7+9>V  
catch(IOException e){e.printStackTrace ();} L !/Zw~  
catch(Exception e){e.printStackTrace ();} c, IAz  
@\ udaZc  
X*'i1)_h  
Utility.log(nFileLength); 10?+6*d  
-jXO9Q  
Epo/}y  
return nFileLength; ks3ydHe`  
} B!J~ t8  
3^!Y9$y1  
zDakl*  
//保存下载信息(文件指针位置) 6*W7I- A  
private void write_nPos() $, I%g<  
{ 4%refqWK  
try{ @Z}TF/Rx4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ' ozu4y  
output.writeInt(nStartPos.length); ^T>P  
for(int i=0;i<nStartPos.length;i++) %s&"gWi  
{ 0j\} @  
// output.writeLong(nPos); nF"NXYa  
output.writeLong(fileSplitterFetch.nStartPos); qcVmt1"  
output.writeLong(fileSplitterFetch.nEndPos); ;RR\ Hwix  
} t%S2D  
output.close(); 7XM:4whw  
} 3UR'*5|'  
catch(IOException e){e.printStackTrace ();} Bp:PAy  
catch(Exception e){e.printStackTrace ();} lE=&hba  
} NuEcTww  
f;{K+\T  
4:zyZu3fm  
//读取保存的下载信息(文件指针位置) {TOz}=R"3h  
private void read_nPos() @~ 6,8nQ  
{ ro}WBv  
try{ /#Fz K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K=K]R01/o  
int nCount = input.readInt(); (&o|}"kRq  
nStartPos = new long[nCount]; w ]%EJ|'  
nEndPos = new long[nCount]; h/s8".\  
for(int i=0;i<nStartPos.length;i++) td!YwN*  
{ b)(si/]\  
nStartPos = input.readLong(); u.yjk/jF  
nEndPos = input.readLong(); xwhS[d  
} dy"7Wl]hi7  
input.close(); 9EFQo^ E  
} O\X=vh/D  
catch(IOException e){e.printStackTrace ();} Pl/B#Sbf'  
catch(Exception e){e.printStackTrace ();} ]H-5    
} P*!~Z *"  
9O4\DRe5c  
z km#w  
private void processErrorCode(int nErrorCode) -`cNRd0n  
{ Z,_EhEm  
System.err.println("Error Code : " + nErrorCode); rnSrkn"j{  
} 7W.z8>p  
4R}$P1 E  
k*u4N  
//停止文件下载 M+l~^E0Wj  
public void siteStop() 1lLXu  
{ -IE=?23Do?  
bStop = true; werTwe2Q  
for(int i=0;i<nStartPos.length;i++) E0t%]?1  
fileSplitterFetch.splitterStop(); 8+mu'RZ X  
W.sH  
|_\q5?S  
} oAt{ #v  
} {>h,@  
//负责部分文件的抓取 ],|;  
**FileSplitterFetch.java f\u5=!kjN  
*/ 19]O;  
package NetFox; ` st^i$A  
D6fGr$(N%  
l\6.f_  
import java.io.*; dTVh{~/  
import java.net.*; (.~,I+Cz'  
tSX,*cz  
CyKupJ.Fq  
public class FileSplitterFetch extends Thread { z{ (c-7*  
M?v`C>j  
fO{'$?K  
String sURL; //File URL s*tzU.E (  
long nStartPos; //File Snippet Start Position OrRU$5Lo  
long nEndPos; //File Snippet End Position -Gj."ks  
int nThreadID; //Thread's ID $h|8z  
boolean bDownOver = false; //Downing is over v$~ZT_"(9  
boolean bStop = false; //Stop identical )U +Pt98"  
FileAccessI fileAccessI = null; //File Access interface *@E&O^%cO  
2>F `H7W  
#9/S2m2\YG  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException # XeEpdE  
{ F*_ytL  
this.sURL = sURL; 7hAc6M$h;  
this.nStartPos = nStart; A 6j>KTU  
this.nEndPos = nEnd; oV;I8;#\J  
nThreadID = id; rrrn8b6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 yv(\5)XF  
} '/GZ/$a_l  
0 czEA  
ia*Bcx_RW+  
public void run() h,x'-]q  
{ =SK{|fBB  
while(nStartPos < nEndPos && !bStop) *kq>Z 06'i  
{ ' p!\[* e  
W@WKdaJ  
Ey]P >J  
try{ "%dok@v  
URL url = new URL(sURL); pIgjo>K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +8 }p-<a  
httpConnection.setRequestProperty("User-Agent","NetFox"); aMO+ y91Y(  
String sProperty = "bytes="+nStartPos+"-"; - -ZSl  
httpConnection.setRequestProperty("RANGE",sProperty); %&&;06GU}  
Utility.log(sProperty);  MuP&m{  
ZJ'FZ8Sx  
_8s1Wh G  
InputStream input = httpConnection.getInputStream(); 8?[#\KgH1  
//logResponseHead(httpConnection); 6B&ERdoX  
G0Wv=tX|  
%R-KkK<S  
byte[] b = new byte[1024]; FQO>%=&4  
int nRead; HyJ&;4rf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) q/3 )yG6s  
{ - %`iLu  
nStartPos += fileAccessI.write(b,0,nRead); *:,y`!F=y  
//if(nThreadID == 1) 8+8P{_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D`@*udn=  
} lk%W2N5  
"a]Ff&T-  
1J[|Ow  
Utility.log("Thread " + nThreadID + " is over!"); T UO*w  
bDownOver = true; ]oE:p  
//nPos = fileAccessI.write (b,0,nRead); *v0}S5^ /"  
} 89l{h8R  
catch(Exception e){e.printStackTrace ();} T]y^PT<8?  
} C^9bur/  
} `t Zw(Z=h  
}Oe9Zq  
!~a1xI~s  
//打印回应的头信息 {f[X)  
public void logResponseHead(HttpURLConnection con) O;SD90  
{ V"W)u#4,  
for(int i=1;;i++) *S\/l-D  
{ :'K%&e?7s  
String header=con.getHeaderFieldKey(i); t_{rKb,  
if(header!=null) B$&&'i%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Z)dE#A_X  
Utility.log(header+" : "+con.getHeaderField(header)); hgI;^ia  
else 0|OmQ\SQ  
break; _?~)B\@~0  
} @ >Ul0&Mf?  
} tjt#2i8/  
{aYCrk1  
/+{1;}AT  
public void splitterStop() O>Ao#_*hOb  
{ U=>4=gsG  
bStop = true; 4kdQ h]  
} SAtK 'Jx[  
@ Yzc?+x  
:yE7jXB  
} }@NT#hD  
5d5q0bb  
;(~H(]D  
/* P'p5-l UK  
**FileAccess.java #hP&;HZ2>"  
*//文件访问(定位,写) _%6Vcy  
package NetFox; d ~3G EK  
import java.io.*; N Uq'96 {Y  
_do(   
Y|y X]\,  
public class FileAccessI implements Serializable{ <O30X !QuK  
n ;0x\Q|S  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 qFg"!w  
RandomAccessFile oSavedFile; (d$ksf_[%f  
long nPos; Kk<MS$Ov  
 4xnM7t\  
4Q5 c'  
public FileAccessI() throws IOException rhvTV(Bz  
{ u<a =TPAU  
this("",0); sN9 SuQ  
} .qG*$W2f  
)1 =|\  
# vBS7ba  
public FileAccessI(String sName,long nPos) throws IOException UJ1Ecob  
{ _.G p}0a  
oSavedFile = new RandomAccessFile(sName,"rw"); 1)N{!w`  
this.nPos = nPos; k{d)'\FM  
oSavedFile.seek(nPos); BuIly&qbm<  
} +Rb0:r>kU  
aIW W[xZ  
v#o<. Ig  
public synchronized int write(byte[] b,int nStart,int nLen) $H2HVJ  
{ _ ZC[h~9H  
int n = -1; a~"<lzu|$  
try{ _M9-n  
oSavedFile.write(b,nStart,nLen); 7l|D!`BS  
n = nLen; v|K<3@J  
} 2[Q/|D}}|  
catch(IOException e) /ng +IC3  
{ Q ^z&;%q1  
e.printStackTrace (); "8YXFg  
} ]eD5It\  
L#X!.  
V=DT.u  
return n; )3RbD#?  
} > Vvjs  
L fx$M  
|"XxM(Dm  
} E2a00i/9Y  
1X$hwkof  
KD)+& 69  
/* N0 F|r8xS  
**SiteInfoBean.java !JE=QG"  
*/ qD?-&>dBWi  
package NetFox; =Zc Vywz;+  
QwL'5ws{q  
sU }.2k  
public class SiteInfoBean { qH-':|h7  
H<bK9k)E  
q*B(ZG  
private String sSiteURL; //Site's URL h.D*Y3=<  
private String sFilePath; //Saved File's Path .ECT  
private String sFileName; //Saved File's Name ?Pw(  
private int nSplitter; //Count of Splited Downloading File -yH8bm'0"  
M4m90C;dq  
1=.+!Tg  
public SiteInfoBean() b3RCsIz  
{//nSplitter的缺省值为5 Z UCz-53  
//default value of nSplitter is 5 +~ L26T\8  
this("","","",5);  >!7\Rx  
} J SOgq/\  
/>E:}1}{  
Wu9))Ir  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3Az7urIY  
{ !1s^TB>N  
sSiteURL= sURL; _Bhm\|t  
sFilePath = sPath; qe\JO'g#e  
sFileName = sName; {f kP|d  
this.nSplitter = nSpiltter; @p}"B9h*^  
;[>g(W+  
hRWRXC 9  
} DRUvQf  
Ar:ezA  
2UGnRZ8:1Y  
public String getSSiteURL() j/<z[qr  
{ PWw2;3`-6w  
return sSiteURL; E0Neo _7  
}  !Hp H  
!^EdB}@yS  
]@D#<[5\  
public void setSSiteURL(String value) %Z#s9QC  
{ |#6))Dh  
sSiteURL = value; $<N!2[I L  
} _jr'A-M  
^Td_B03)  
#=* y7w  
public String getSFilePath() JM?X]l  
{ K V-}:u(  
return sFilePath; _:Jra  
} ?\D=DIN-r  
8A3pYW-  
R^*h|7)E  
public void setSFilePath(String value) Z1t?+v+Ro*  
{ dY'mY~Tv  
sFilePath = value; t@(`24  
} `0qBuE_^h  
P b(XR+  
UD@u hL  
public String getSFileName() c+^#(OB  
{ _CDl9pP36#  
return sFileName; @Pt,N qj:  
} =oPc\VYW  
IV5B5Q'D  
jbU=D:|  
public void setSFileName(String value) >P/Nb]C  
{ 1 ynjDin<  
sFileName = value; T1&^IO-F7$  
} 3Wl,T5}{  
]$VYzE2e  
j.FW*iX1C  
public int getNSplitter() ?t JyQT  
{ 2W_p)8t> b  
return nSplitter; DG!H8^  
} S|pMX87R  
\~:Uj~  
AUk,sCxd  
public void setNSplitter(int nCount) 3i c6!T#t"  
{ EGKj1_ml  
nSplitter = nCount; )t-Jc+*A>  
} wf= s-C  
} ^^-uq)A  
W_ =  
WjrUns  
/* CfWtCA  
**Utility.java %bp8VR sY  
*/ 7K|: 7e(  
package NetFox; F{g^4  
tL;!!vg#V  
LXm5f;  
public class Utility { d\R]>  
fW,,@2P  
b& l/)DU  
public Utility() &%ZiI@O-  
{ TC=djC4$/  
o?Wp[{K  
h5:>o  
} m\}8N u  
EP|OKXRltA  
//线程睡眠 %L\buwjy$  
public static void sleep(int nSecond) jBTXs5q  
{ J9kmIMq-C  
try{ FHu -';  
Thread.sleep(nSecond); c~1X/,biA  
} nS53mLU)  
catch(Exception e) *,UD&N_)*6  
{ Dj~]]  
e.printStackTrace (); Y~</vz+H  
} y$]gmg  
} 4a&*?=GG  
TaZw_)4c  
//日志 XYOPX>$T  
public static void log(String sMsg) @Y~R*^n"}  
{ yJheni  
System.err.println(sMsg);  fn1G^a=  
} `o.DuvQ E  
\1AtB c&  
epWO}@ b a  
public static void log(int sMsg) x*EzX4$x  
{ sUfYEVjr  
System.err.println(sMsg); >|"mhNF  
} 7.r}98V  
} cPemrNxydN  
;}tEU'&  
v[aFSXGj)  
/* :DxCjv  
**TestMethod.java hr+,-j  
*/ x}`]9XQ  
package NetFox; qm.30 2  
+EmT+$>J  
0u?{"xH{+}  
public class TestMethod { yC]xYn)  
GAZw4 dz  
C^o9::ER  
public TestMethod() ;Jn"^zT  
{ ///xx/weblogic60b2_win.exe 7# /c7   
try{ jL|y4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?HP54G<{xz  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5&y;r  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \,w*K'B_Y  
fileFetch.start(); zH1pW(  
} 5kK:1hH7  
catch(Exception e){e.printStackTrace ();} gbf-3KSp^  
Myl!tXawe8  
]kN<N0;\d  
} ?y] q\>  
62R9 4  
{M7`z,,[  
public static void main(String[] args) JH%^FF2  
{ [|=#~(yYQ  
new TestMethod(); -`iXAyr)m  
} Y7vTseq  
} Nn"[GB  
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