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http断点续传简单实现(java)

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/* 7t04!dD}  
**SiteFileFetch.java Ox~'w0c,f  
*/ Tc88U8Gc  
package NetFox; _).'SU)>  
import java.io.*; W;N/Y3Lb  
import java.net.*; 'hek CZZ_I  
?Nh%!2n  
s3+O=5  
public class SiteFileFetch extends Thread { gw*d"~A  
m@O\Bi}=}  
9wq%Fnt  
SiteInfoBean siteInfoBean = null; //文件信息Bean ZM#WdP  
long[] nStartPos; //开始位置 Pm1 " 0  
long[] nEndPos; //结束位置 @Qs-A^.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !GIsmqVY  
long nFileLength; //文件长度 HQ s)T  
boolean bFirst = true; //是否第一次取文件 pK8nzGQl7  
boolean bStop = false; //停止标志 __ mtZ{  
File tmpFile; //文件下载的临时信息 !%u#J:z2  
DataOutputStream output; //输出到文件的输出流 9#iDrZW  
5dgBSL$A}]  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 4]B3C\ v  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^mum5j  
{ R$fna[Xw@/  
siteInfoBean = bean; *2AQ'%U~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /B!m|)h5~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); y:A0!75  
if(tmpFile.exists ()) fiZv+R<x1  
{ okcl-q  
bFirst = false; 2 YN` :"  
read_nPos(); FvJSJ.;E,  
} GBphab|  
else {;4PP463  
{ Qi[D&47XO  
nStartPos = new long[bean.getNSplitter()]; b;t]k9:"L  
nEndPos = new long[bean.getNSplitter()]; -Y[-t;  
} t~M<j| ]k  
gPwp [  
v)d0MxSC  
2 T3DV])Q  
} MJG%HakK0  
5i^vN"J  
tbPPI)lu  
public void run() (Z$6J Nkz  
{ >o} ati  
//获得文件长度 s =5H.q%PV  
//分割文件 q],R6GcVr  
//实例FileSplitterFetch P\ s+2/  
//启动FileSplitterFetch线程 jkP70Is  
//等待子线程返回 KNg5Ptk  
try{ Q'a N|^w"f  
if(bFirst) 1ZL_;k  
{ +wUhB\F *  
nFileLength = getFileSize(); Dgm%Ng  
if(nFileLength == -1) 84!4Vz^  
{ ,>UmKrYo  
System.err.println("File Length is not known!"); *i{.@RX?  
} ->hxHr`!%a  
else if(nFileLength == -2) m6x. "jG  
{ Yy)a,clZ*$  
System.err.println("File is not access!"); cA%U  
} Zd(d]M_x  
else 7:L~n(QpP  
{ 668bJ.M\O  
for(int i=0;i<nStartPos.length;i++) c_q+_$t  
{ M([H\^\:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~yi&wbTjM  
} \!QF9dP4  
for(int i=0;i<nEndPos.length-1;i++) =Yj[MVn  
{ lkZC?--H  
nEndPos = nStartPos[i+1]; 5 WppV3;  
} 5tU"|10m3  
nEndPos[nEndPos.length-1] = nFileLength; 5)zB/Ta<  
} nTU~M~gky  
} ? 03Zy3 /  
(d;(FBk='  
iy82QNe  
//启动子线程 'c[LTpn4=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t4k'9Y:\Q  
for(int i=0;i<nStartPos.length;i++) <PN;D#2bh  
{ />[6uvy#Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4)iEj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <e&QTyb  
nStartPos,nEndPos,i); 'TrrOq4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G r|@CZq  
fileSplitterFetch.start(); I=%sDn  
} mY 8=qkZE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >ij4z N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /V<`L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B ^(rUR  
nEndPos = " + nFileLength); $l;tP  
// fileSplitterFetch[nPos.length-1].start();  DiQkT R  
b<(UmRxx3  
% B &?D@  
//等待子线程结束 I*t)x,~3  
//int count = 0; ~9 WJrRWB  
//是否结束while循环 ,Q#tA|:8j  
boolean breakWhile = false; /Z " 4[  
/C"s_:m;3  
fF>qU-  
while(!bStop) aaug u.9  
{ I!7.fuO  
write_nPos(); 70 UgKE  
Utility.sleep(500); !(_xu{(DL  
breakWhile = true; 7 3z Y^ x  
9H}iX0O  
A4Q)YY9~  
for(int i=0;i<nStartPos.length;i++) K^vp(2  
{ z){UuiUM+=  
if(!fileSplitterFetch.bDownOver) !-RpRRR[Co  
{ +R#`j r"  
breakWhile = false; SfobzX}~Jh  
break; 8*#][ wC2  
} ]az} n(B,  
} 6>BDA?  
if(breakWhile) kw^Dp[8X  
break; @!a]qAt  
D^s0EW-E  
;]ShC\1  
//count++; uP=_-ZUW  
//if(count>4) e3={$Ah  
// siteStop(); Z^`=!n-V  
} g} ~<!VpX  
3:8nwt  
:iQ^1S` pH  
System.err.println("文件下载结束!"); fI d)  
} mYjiiql~  
catch(Exception e){e.printStackTrace ();} iRwW>a3/  
} 9h38`*Im;  
:IT U0%;!+  
d)GkXll1D  
//获得文件长度 @oqi@&L'C  
public long getFileSize() VtzmY  
{ !+45=d 5  
int nFileLength = -1; Go+xL/f  
try{ F}B/-".^  
URL url = new URL(siteInfoBean.getSSiteURL()); ~R?dDL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9Oo*8wvGG  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;Jbc'V'fm  
9MtJo.A  
/IJ9_To  
int responseCode=httpConnection.getResponseCode(); 88np/jvC{  
if(responseCode>=400) <#p|z`N  
{ -KwL9J4u  
processErrorCode(responseCode); dI ZTLb"a  
return -2; //-2 represent access is error %QsSR'`  
} c7l!G~yx'  
So\|Ye  
>_0 i=.\  
String sHeader; Q"6hD?6.  
e7bT%h9i  
qgC-@I  
for(int i=1;;i++) v_ nBh,2  
{  `\|3 ~_v  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _/]:=_bf_z  
//Utility.log(in.readLine()); G\:psx/  
sHeader=httpConnection.getHeaderFieldKey(i); t1:S!@  
if(sHeader!=null) 8/>wgY  
{ 3^A/`8R7K  
if(sHeader.equals("Content-Length")) ,F?~'-K  
{ 28Ssb|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); b?2X>QJ  
break; ;+ C o!L  
} ^0-e,d 9h  
} 3dxnh,]&@  
else yrE,,N%I  
break; F'UguC">  
} Z}K.^\S9  
} [zh4W*K_cq  
catch(IOException e){e.printStackTrace ();} cJHABdK-  
catch(Exception e){e.printStackTrace ();} <(bCz>o|  
PK 2Rj%  
@O<@f8-  
Utility.log(nFileLength);  UE&C  
o! 2 n}C  
l)i &ATvCE  
return nFileLength; Q/3tg  
}  *_ {l  
p(H)WD  
"BLv4s|y7L  
//保存下载信息(文件指针位置) ||'i\X|[  
private void write_nPos() N[a ljC-R  
{ \=EY@ *=  
try{ [DotS\p!z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Rg8m4xw  
output.writeInt(nStartPos.length); s}[A4`EWH  
for(int i=0;i<nStartPos.length;i++) 38w.sceaT  
{ C)J_lI{^  
// output.writeLong(nPos); (?!(0Ywbg  
output.writeLong(fileSplitterFetch.nStartPos); q lz9&w  
output.writeLong(fileSplitterFetch.nEndPos); ;e~{TkD  
} Ere?d~8  
output.close(); o8};e  
} <uBhi4  
catch(IOException e){e.printStackTrace ();} #Cg}!38  
catch(Exception e){e.printStackTrace ();} +#-kIaU  
} q:2aPfo&  
*;OJ ~zT  
[xZ/ZWb/  
//读取保存的下载信息(文件指针位置) C-a*EG  
private void read_nPos() aDN6MZM  
{ 2,8/Cb  
try{ *l>[`U+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;T5,T   
int nCount = input.readInt(); b"R, p=M  
nStartPos = new long[nCount]; 5#TrCPi6A  
nEndPos = new long[nCount]; ,c,Xd  
for(int i=0;i<nStartPos.length;i++) RV0>-@/x  
{ -~v l+L  
nStartPos = input.readLong(); RjR&D?dc  
nEndPos = input.readLong(); C@TN5?Z  
} {[M0y*^64$  
input.close(); o~OwE7H)A  
} z`emKFbv  
catch(IOException e){e.printStackTrace ();} >%uAQiU  
catch(Exception e){e.printStackTrace ();} :rz9M@7  
} p4m^ ~e  
1a($8>  
,2 zt.aqB  
private void processErrorCode(int nErrorCode) <&qpl0U)Y  
{ laUu"cS  
System.err.println("Error Code : " + nErrorCode); 3bbp>7V!  
} &Q-[;  
H Z;ZjC*  
/~o7Q$)-b  
//停止文件下载 `y8 ?=  
public void siteStop() ~")h E%Kl}  
{ (R4PD  
bStop = true; sBP}n.#$  
for(int i=0;i<nStartPos.length;i++) 5cyddlaat  
fileSplitterFetch.splitterStop(); o }9M`[  
2Ueq6IuQ  
!Y ;H(.A/  
} T[5gom  
} P &;y] ,)E  
//负责部分文件的抓取 Od0S2hHO  
**FileSplitterFetch.java _u:>1]  
*/ Qqd6.F  
package NetFox; pP|,7c5  
UJee&4C-y  
 /6+1{p  
import java.io.*; !cq=)xR  
import java.net.*; "C_T]%'Wm  
!Gln Q`T  
5x*5|8  
public class FileSplitterFetch extends Thread { f,St h7y  
nc3sty1`  
ES^>[2Y  
String sURL; //File URL ;j>*;Q`  
long nStartPos; //File Snippet Start Position 0lX)Cl  
long nEndPos; //File Snippet End Position mgi,b2  
int nThreadID; //Thread's ID %v5)s(Yu  
boolean bDownOver = false; //Downing is over lhLnygUk  
boolean bStop = false; //Stop identical *)MX%`Z}  
FileAccessI fileAccessI = null; //File Access interface C>*5=p|T  
N=OS\pz  
)>(L{y|uYX  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gKmX^A5<  
{ GE%2/z p  
this.sURL = sURL; |0tg:\.  
this.nStartPos = nStart; ./5jx2V  
this.nEndPos = nEnd; 7m@ )Lv  
nThreadID = id; Ihdu1]~R{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 V -q%r  
} E|pk.  
VLf g[*k  
Q Oz9\,C  
public void run() r8IX/ ,  
{ oS~}TR:}  
while(nStartPos < nEndPos && !bStop) }X=87ud  
{ w+q?T  
\.c]kG>k-  
M6J/mOVx5  
try{ _Ny8j~  
URL url = new URL(sURL); =kd YN 5R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,5/V@;i  
httpConnection.setRequestProperty("User-Agent","NetFox"); sC% b~  
String sProperty = "bytes="+nStartPos+"-"; -@rxiC:Q  
httpConnection.setRequestProperty("RANGE",sProperty); ?Q@L-H`  
Utility.log(sProperty); `'u Umyg  
D,MyI#  
Ej' 7h~=v  
InputStream input = httpConnection.getInputStream(); Z`rK\Bc  
//logResponseHead(httpConnection); >4,{6<|  
%PzQ\c  
vKU`C?,L  
byte[] b = new byte[1024]; yc*<:(p  
int nRead; >B0D/:R9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |Dg;(i?  
{ , Hn7(^t  
nStartPos += fileAccessI.write(b,0,nRead);  VJ3hC[  
//if(nThreadID == 1) bFSlf5*H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pFpZbU^  
} (Up'$J}  
#e*X0;m  
Ejq=*UOP  
Utility.log("Thread " + nThreadID + " is over!"); ]$3+[9x'  
bDownOver = true; mV<i JZh  
//nPos = fileAccessI.write (b,0,nRead); 8)sg_JC  
}  2A*/C7  
catch(Exception e){e.printStackTrace ();} G-arnu)  
} !(Q l)C  
} nB=0T`vQ  
Y[Es  
~uB'3`x  
//打印回应的头信息 DR6]-j!FK  
public void logResponseHead(HttpURLConnection con) )%s +?  
{ B#]_8svO  
for(int i=1;;i++) tVunh3-  
{ cqEHYJ;B  
String header=con.getHeaderFieldKey(i); Xem 05%,  
if(header!=null) wy''tqg6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ` K w7"  
Utility.log(header+" : "+con.getHeaderField(header)); Y~az!8j;Z  
else Id %_{),HX  
break; }&1Iyb  
} *wwhZe4V  
} yLW/ -%I#u  
27>a#vCT  
va5FxF*%  
public void splitterStop() =N_,l'U\^  
{ 9RxO7K  
bStop = true; "IG+V:{ou  
} k^^:;OR  
uArR\k(  
2/@D7>F&g  
} >\Z R*CS  
k5@d! }#c  
8a9RML}G<  
/* 8Y# bN*!  
**FileAccess.java %w7m\nw@  
*//文件访问(定位,写) ZW*n /#GUC  
package NetFox; \X& C4#  
import java.io.*; u?kD)5Nk  
!qA8Zky_  
azo0{`S?  
public class FileAccessI implements Serializable{ < A?<N?%o  
snYr9O[E6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6 mO"  
RandomAccessFile oSavedFile; |) Pi6Y  
long nPos; t8& q9$  
Jf)3< ~G  
:tM?%=Q  
public FileAccessI() throws IOException b{RqwV5P  
{ fYBH)E  
this("",0); H] k'?;  
} jJ~Y]dQi  
zE`R,:VI  
0+EN@Y^dAV  
public FileAccessI(String sName,long nPos) throws IOException Uki9/QiX>  
{ 5 lTD]d  
oSavedFile = new RandomAccessFile(sName,"rw"); Q.k :\m*h  
this.nPos = nPos; /s c.C  
oSavedFile.seek(nPos);  ]>Si0%  
} i[150g?K  
&aPl`"j  
%jEY 3q  
public synchronized int write(byte[] b,int nStart,int nLen) <tbZj=*O/o  
{ i"HgvBHx  
int n = -1; 9cd8=][  
try{ K)S;:MLG=  
oSavedFile.write(b,nStart,nLen); 5j eO"jB  
n = nLen; rGlRAn#?,  
} 5j{Np,K  
catch(IOException e) r7 VXeoX  
{ ug *D52?  
e.printStackTrace (); s /%:dnij  
} n|i"S`  
:EZQ'3X  
++8_fgM  
return n; lJ{V  
} 1$ML#5+,  
mJC3@V s  
PJgp+u<  
} #U=;T]!'$  
\t3qS eWc/  
4:mCXP,x  
/* |NrrTN?>  
**SiteInfoBean.java 0xpx(T[  
*/ }B q^3?,#{  
package NetFox; 47UO*oLS  
T&xt` |  
MJ\[Dt  
public class SiteInfoBean { *8)2iv4[  
W f@t4(i  
ALGg AX3t  
private String sSiteURL; //Site's URL <L2emL_'  
private String sFilePath; //Saved File's Path {8@\Ij  
private String sFileName; //Saved File's Name N[Sb#w`[/  
private int nSplitter; //Count of Splited Downloading File _3>djF_u  
O8|*M "  
4 tXSYHd3  
public SiteInfoBean() 1;&;5  
{//nSplitter的缺省值为5 =Q(vni83<  
//default value of nSplitter is 5 DjHp+TyT  
this("","","",5); 8)xt(~qF  
} ~rv})4h  
$/_ qE  
0 ^~\COa  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .Q>!B?)  
{ VC-;S7k  
sSiteURL= sURL; (j&A",^^S  
sFilePath = sPath; Veji^-0E  
sFileName = sName; rt4Z;  
this.nSplitter = nSpiltter; O~@fXMthh  
g4&jo_3:p  
xh0xSqDM  
} T_#, A0G  
-<N&0F4|*  
K`k'}(vj  
public String getSSiteURL() /_\W+^fE  
{ 4MW ]EQ-  
return sSiteURL; uQeu4$k!  
} fgF;&(b  
Ec]|p6a3  
o6}n8U}bk  
public void setSSiteURL(String value) *'ZN:5%H  
{ x5Zrz<Y$w  
sSiteURL = value; hu5!ev2  
} #^rU x.  
2KI!af[I  
]hTb@.  
public String getSFilePath() l@~LV}BI  
{ RL}KAGK  
return sFilePath; YQ(Po!NI\'  
} 2t1I3yA'{z  
`/Y+1 aD  
Lz4eh WntO  
public void setSFilePath(String value) Bw< rp-  
{ Z1,gtl ?  
sFilePath = value; Hs0pW5oZ  
} >q7 %UK]&  
&ak6zM  
gPEqjj  
public String getSFileName() y,m2(V  
{ H{fM%*w  
return sFileName; WDx Mo`zT  
} ?Zcj}e.r  
\pY^^ l*  
-50AX1h31:  
public void setSFileName(String value) ;Zut@z4\  
{ `M@Ak2gcR+  
sFileName = value; Y2T$BJJ  
} kA#vByf`v  
6*XM7'n  
8i 0  
public int getNSplitter() hW 2.8f$  
{ &M"ouy Zo9  
return nSplitter; wH6u5*$p  
} \2X$C#8E  
F 3RB  
s& yk  
public void setNSplitter(int nCount) =mt?C n}  
{ Utt>H@t[  
nSplitter = nCount; E{Vo'!LY  
} n9hm790x-  
} ;b%{ilx:  
A7-r <s  
<94G  
/* *\XH+/]+  
**Utility.java RtV.d \  
*/ 8^yJqAXK  
package NetFox; .y4&rF$n  
?nFO:N<  
"mIgs9l$  
public class Utility { B BL485`  
Hi,t@!!  
ffcLuXa  
public Utility() @}LZ! y  
{ RA/EpD:H  
ps1@d[n  
sH!O0WL  
} lZ+!H=`  
')#,X^   
//线程睡眠 TZB+lj1  
public static void sleep(int nSecond) x8[MP?Wz  
{ =dH$2W)G  
try{ HFtf  
Thread.sleep(nSecond); 1]OSWCEm*[  
} UuJjO^t  
catch(Exception e) *^XbDg9  
{ (GU9p>2  
e.printStackTrace (); lAASV{s{  
} 4tc:.  
} )ly ^Ox  
g`,AaWlF  
//日志 ;Ss$2V'a  
public static void log(String sMsg) y{=NP  
{ d#_m.j  
System.err.println(sMsg); /g.]RY+u|x  
} Tj/GClD:%  
;!u;!F!i  
Kn}ub+ "J  
public static void log(int sMsg) dbF M,"^  
{ :Ml7G  
System.err.println(sMsg); l?E|R Kp  
} mP}#Ccji?  
} Np,2j KF(  
=,/D/v$m'2  
xAdq+$><  
/* d>i13d AI  
**TestMethod.java Z`_.x &Y  
*/ h'5Cp(G  
package NetFox; %FA@)?~  
Fvl`2W94;  
h%}( h2 W  
public class TestMethod { <[Oo*:A!7  
< K %j  
] |Zb\{  
public TestMethod() 9O98Q6-s  
{ ///xx/weblogic60b2_win.exe <@#PF$!  
try{ 2C "=!'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); M<`|CVl  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); d,F5:w&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #@//7Bf%  
fileFetch.start(); ~L?nq@DL  
} XW~bu2%{7"  
catch(Exception e){e.printStackTrace ();} aW;aA'!  
!{%G0(Dv  
665[  
} Q< *8<Oo4g  
?p^2Z6J'$  
8tc*.H{^+  
public static void main(String[] args) %'ZN`XftG  
{ < oI8-f  
new TestMethod(); AXW!]=?X  
} :)c80`-E  
} ]7/gJ>g,  
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