http断点续传简单实现（java)

/* qj.>4d  
**SiteFileFetch.java ;q"Yz-3  
*/ ~[N"Q|D3Y  
package NetFox;  /#FU"  
import java.io.*; NMy+=GZu^  
import java.net.*; -%G}T}"_  
t| cL!  
|_h$}~;  
public class SiteFileFetch extends Thread { qN=l$_UD  
)01,3J>#  
^ UDNp.6k  
SiteInfoBean siteInfoBean = null; //文件信息Bean u4KP;_,m  
long[] nStartPos; //开始位置 #$dEg  
long[] nEndPos; //结束位置 f{HjM? Mb3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S- N [  
long nFileLength; //文件长度 o5(~nQ  
boolean bFirst = true; //是否第一次取文件 i"_@iN0N  
boolean bStop = false; //停止标志 \@8.BCWK  
File tmpFile; //文件下载的临时信息 K*/X{3J;  
DataOutputStream output; //输出到文件的输出流 c/'Cju W  
Iq?#kV9)  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <Pnz$nH:e  
public SiteFileFetch(SiteInfoBean bean) throws IOException Sb|9U8h  
{ >WZ_) `R  
siteInfoBean = bean; 6OPYq*|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,_
iR  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); vVyX[
ZZ  
if(tmpFile.exists ()) p"dK,A5#)  
{ x|=]Xxco  
bFirst = false; O;6am++M@  
read_nPos(); qib4DT$v-6  
} _!ITCkBj  
else />dH\KvN  
{ u}0U!
 
nStartPos = new long[bean.getNSplitter()]; |y%M";MI  
nEndPos = new long[bean.getNSplitter()]; -Pt']07E  
} = }!4%.$  
IQ]tcSQl  
FhFP M)[  
L60Sc  
} ,7/F?!G!J  
s#* DY  
%+bw2;a6  
public void run() - %'ys  
{ F8pP(Wl  
//获得文件长度 \:5M
0  
//分割文件 w|G4c^KH  
//实例FileSplitterFetch \1MMz Z4rf  
//启动FileSplitterFetch线程 = lMs1}S9  
//等待子线程返回 T*"*##c  
try{ LcW
:vV|'K  
if(bFirst) LDgGVl  
{ K^Ixu~  
nFileLength = getFileSize(); 6mml96(  
if(nFileLength == -1) c?t,,\o(}  
{ x!`~+f.6  
System.err.println("File Length is not known!"); mM;5UPbZ  
} K)&oDwk  
else if(nFileLength == -2) L3J .Oh  
{ r"hogmFD;  
System.err.println("File is not access!"); }1BpIqee  
} 2PDU(R  
else ~a06x^=j  
{ y3Q2d7G  
for(int i=0;i<nStartPos.length;i++) n1Fp$9%  
{ 2S@aG%-)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gw_]Y^U  
} GS qt:<Qs  
for(int i=0;i<nEndPos.length-1;i++) TD^w|U.  
{ pRc<U^Z.h  
nEndPos = nStartPos[i+1]; =%ry-n G  
} P+gYLX8  
nEndPos[nEndPos.length-1] = nFileLength; ;NPbEPL[5  
}  )k6O  
} @#1T-*  
=2&Sw(6j  
Z~Vups#+f  
//启动子线程 8-geBlCE,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \wb
0%> 0  
for(int i=0;i<nStartPos.length;i++) /s[D[:P_  
{ 1MYA/l$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TO]7%aB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), zi?G wh~  
nStartPos,nEndPos,i); F- l!i/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =67tQx58  
fileSplitterFetch.start(); E,gpi  
} $/|2d4O:{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >`)IdX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Xo/0lT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3aERfIJyE  
nEndPos = " + nFileLength); Scz/2vNi`  
// fileSplitterFetch[nPos.length-1].start(); Z_WJgH2c  
<E1ngG  
?>T (  
//等待子线程结束 17) `CM$<[  
//int count = 0; yN:U"]glC  
//是否结束while循环 4&}dA^F  
boolean breakWhile = false; /=+Bc=<lZ  
~0T,_N  
5hg ^K^ZZ  
while(!bStop) ,cwjieM  
{ +WfO2V.
 
write_nPos(); <-s5 ;xwtS  
Utility.sleep(500); %O02xr=  
breakWhile = true; 8iXt8XY3  
<:!;79T\  
ODyKS;   
for(int i=0;i<nStartPos.length;i++) t<H@c9{;*  
{ DEN (pA\  
if(!fileSplitterFetch.bDownOver) a8v9j3.  
{ 0s o27k  
breakWhile = false; t(r}jU=qw  
break; k35E,?T  
} %C=?Xhnv  
} /PTk296@  
if(breakWhile) =BVBCh  
break; }U_z XuUz  
mgI7zJX  
_eg&j  
//count++; Og/@w&  
//if(count>4) .EdQ]c-E=  
// siteStop(); <}n"gk1is  
} \\v1\  
vQsI^
p  
z z2'h>  
System.err.println("文件下载结束！"); WOR H4h9  
} wpV)y Q^  
catch(Exception e){e.printStackTrace ();} bPHtP\)  
} ~F^7L5d}C  
8%#pv
}  
]>H'CM4JR  
//获得文件长度 [*W l=  
public long getFileSize() OTV$8{  
{ I*OJPFZ^4  
int nFileLength = -1; L`n Ma  
try{ bY!1t}ALh  
URL url = new URL(siteInfoBean.getSSiteURL()); k:*(..!0z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iVAAGZ>am  
httpConnection.setRequestProperty("User-Agent","NetFox"); GQ])y  
@78%6KZ`i  
lm\~_ 4l1  
int responseCode=httpConnection.getResponseCode(); 'l&bg8K9  
if(responseCode>=400) /;9iDjG  
{ h-6zQs  
processErrorCode(responseCode); #@8JYzMq%  
return -2; //-2 represent access is error 0;SRmj@W  
} (^9dp[2  
2x<4&^  
0o_wy1O1,  
String sHeader; xQ~N1Y2W  
4>}qdR1L4  
q&d5V~q  
for(int i=1;;i++) R~!md  
{ -YJ4-]Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); b1Fd]4H3P  
//Utility.log(in.readLine()); U_61y;Q"  
sHeader=httpConnection.getHeaderFieldKey(i); _h0hl]rf  
if(sHeader!=null) 5rUDRFO6  
{ =VvQ2Y0h8  
if(sHeader.equals("Content-Length")) #-9@*FFL,  
{ T
[+~-D @  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); tL}_kK_!  
break; TM<;Nj[*n  
} {/}p"(
^  
} ~LSD\+  
else f,0,:)  
break; i[40p!~  
} *G(ZRj@33  
} T)tf!v3v  
catch(IOException e){e.printStackTrace ();} K</="3 HK  
catch(Exception e){e.printStackTrace ();} b|E1>TkY  
KGNBzy~9  
T%[!m5   
Utility.log(nFileLength);  j*#k%;c  
cd:VFjT  
ObEp0-^?  
return nFileLength; 09sdt;V Q  
} W'}^m*F  
D3y4e8+Z'  
1U ='"  
//保存下载信息（文件指针位置） R9UC0D:-x  
private void write_nPos() V=c?V
/pl  
{ <ILi38%Y  
try{ oUB9)C~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); mFE7#OM  
output.writeInt(nStartPos.length); >
"Zn# FY  
for(int i=0;i<nStartPos.length;i++) {_ZbPPh;M"  
{ 4}]In/yA  
// output.writeLong(nPos); !k#N] 9D3  
output.writeLong(fileSplitterFetch.nStartPos); |@hyGu-H+  
output.writeLong(fileSplitterFetch.nEndPos); @Y#TWt#  
} :^]FpUY  
output.close(); ^b*ub(5Ot  
} am/D$
(l1  
catch(IOException e){e.printStackTrace ();} 2SKtdiY  
catch(Exception e){e.printStackTrace ();} eGo$F2C6E  
} 4ZB]n,pfT  
NU[Wj uLG  
_V` QvnT}  
//读取保存的下载信息（文件指针位置） ~L.5;8a3Pe  
private void read_nPos() ZQmg;L&7  
{ 7*4i0{]  
try{ 5,R<9FjW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); lLEEre  
int nCount = input.readInt(); A64c,Uv  
nStartPos = new long[nCount]; ?l`|j*  
nEndPos = new long[nCount]; \*c=b
z&l  
for(int i=0;i<nStartPos.length;i++) =-G4BQ  
{ Sf t,$  
nStartPos = input.readLong(); ")w~pZE&+  
nEndPos = input.readLong(); AS lmW@/9v  
} ~)5k%?.  
input.close(); q2M%AvR  
} N]G`]  
catch(IOException e){e.printStackTrace ();} .G|U#%"6x  
catch(Exception e){e.printStackTrace ();} o^u}(wZ{  
} 4hUUQ;xj  
Nl{on"il  
mHNqzdaa  
private void processErrorCode(int nErrorCode) )F6p+i="  
{ C6d#+  
System.err.println("Error Code : " + nErrorCode); H+Q_%%[N  
} V
C^QCuSq  
&cf_?4  
F^Mt}`O  
//停止文件下载 h\8bo=  
public void siteStop() j)}TZx4~  
{ :{?Pq8jP  
bStop = true;
,MD>Jx|  
for(int i=0;i<nStartPos.length;i++) YwJ<0;:+hS  
fileSplitterFetch.splitterStop(); :oJ!9\5  
UQjZhH  
RI]x=  
} $EZr@n  
} h5[.G!  
//负责部分文件的抓取 ^_o:Ddz?l"  
**FileSplitterFetch.java = Ruq  
*/ !1P<A1K  
package NetFox; ~P9^4  
Fh.ZsPn,m  
`>`{DEDx{5  
import java.io.*; EHt(!;?q  
import java.net.*; &y~GTEP  
S|_lbMZM  
ZMch2 U8  
public class FileSplitterFetch extends Thread { 3UJSK+d\  
ak(P<OC-  
#}8gHI-9%  
String sURL; //File URL mMad1qCi7  
long nStartPos; //File Snippet Start Position 5 Praj  
long nEndPos; //File Snippet End Position >F/5`=/'h  
int nThreadID; //Thread's ID j7C&&G q  
boolean bDownOver = false; //Downing is over g+=f=5I3  
boolean bStop = false; //Stop identical @T{I;8S  
FileAccessI fileAccessI = null; //File Access interface 2X=*;r"{J  
9tB:1n}  
'zQp64]F  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y>K3.*.  
{ ;*e$k7}F  
this.sURL = sURL; I0sw/,J/Z  
this.nStartPos = nStart; ] -G~  
this.nEndPos = nEnd; 8uB6C0,6?  
nThreadID = id; 6Ou[t6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 M_\)<a(8  
} Xyw;Nh!!d  
MG$Df$R  
#:nds,  
public void run() !^w}Sp  
{ e'dZ2;X$zo  
while(nStartPos < nEndPos && !bStop) /x&52~X5-  
{ wdEQB-d
A  
/^Zgv-n  
0+_:^z  
try{ yzz(<s:o/  
URL url = new URL(sURL); )H<F([Jri  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y;tX`5(fe  
httpConnection.setRequestProperty("User-Agent","NetFox"); A<cnIUW  
String sProperty = "bytes="+nStartPos+"-"; K<"Y4O#]  
httpConnection.setRequestProperty("RANGE",sProperty); 9icy&'  
Utility.log(sProperty); ,in"8aT}~  
CSIsi]H  
!,;/JxfgVh  
InputStream input = httpConnection.getInputStream(); .4,l0Nn`W  
//logResponseHead(httpConnection); 3d>xg%?  
S{)'1J_0  
(s!cd]Qa.  
byte[] b = new byte[1024]; )}T0SGY  
int nRead; 19^B610  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *AI
?md  
{ 
yv.(Oy  
nStartPos += fileAccessI.write(b,0,nRead); QCvst*  
//if(nThreadID == 1) =p$:vW
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p}k\l dmh{  
} *7!*kqg!u  
_,E! <  
(1;%V>,L  
Utility.log("Thread " + nThreadID + " is over!"); 4CioVQdj  
bDownOver = true; )Jd{WC.  
//nPos = fileAccessI.write (b,0,nRead); #jX%nqMxW  
} (J\Qo9Il  
catch(Exception e){e.printStackTrace ();} 3AarRQWsn  
} 1EA}
[x  
} Pqv9>N|  
I i J%.U  

_iW-i  
//打印回应的头信息 $4]"g}_  
public void logResponseHead(HttpURLConnection con) -'::$ {  
{ S
cTeh  
for(int i=1;;i++) HiDL:14  
{ YBY!!qjPx  
String header=con.getHeaderFieldKey(i); .k:Uj-&  
if(header!=null) #6qLu  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2W=am_\0e.  
Utility.log(header+" : "+con.getHeaderField(header)); atjrn:X  
else gX*i"Y#
 
break; YDo,9  
} EyPF'|Qtn  
} Z<6Fq*I  
p+|(lrYC  
jRo4+8  
public void splitterStop() xouy|Nn
'  
{ <LOas$
 
bStop = true;  9/R<,  
} }TAHVcX*p  
Rac4a@hZ  
>-<7 r?~  
} 9_\1cSk'  
>&2n\HR\  
%^66(n)  
/* 9Y-6e0B:  
**FileAccess.java RF.8zea{O`  
*//文件访问(定位，写) "ku ?A^f  
package NetFox; >Y[nU~w  
import java.io.*; 'Gds?o8  
\H$j["3  
!JVpR]lWS  
public class FileAccessI implements Serializable{ dEM=U;  
iWu^m+"k  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +b6kU{  
RandomAccessFile oSavedFile; '9#h^.
  
long nPos; 5$p7y:  
]NgEN  
Hze~oAP+  
public FileAccessI() throws IOException ]R  s  
{ Ww$?X LF  
this("",0); f8
?c[%br  
} \3v}:E+3  
!aub@wH3  
qT+:oMrTSm  
public FileAccessI(String sName,long nPos) throws IOException \Z%V)ZRi=  
{ dk4|*
l-  
oSavedFile = new RandomAccessFile(sName,"rw"); G%RhNwm  
this.nPos = nPos; mBZg(TY  
oSavedFile.seek(nPos); |Y\BI^
 
} 3"J85V%h]n  
l\{{iAC]I  
u4p){|x7s  
public synchronized int write(byte[] b,int nStart,int nLen) v22ZwP  
{ p[lciWEW  
int n = -1; V57tn6>b  
try{ QUU'/e2^c  
oSavedFile.write(b,nStart,nLen); &lYe  
n = nLen; *wetPt)~v_  
} xnm!$ $W  
catch(IOException e) G.
#sX  
{ \@i4im@%xU  
e.printStackTrace (); kan4P@XVS  
} l&1R`gcW  
;+h-o  
' ;PHuMY#X  
return n; )w3HC($g  
} 8f0Ytfhw  
4?)-;Hx_X  
t&99ZdE  
} &;O)Dw  
IrZ!.5%tV  
P<WCW3!JZ  
/* *nh.&Mv|  
**SiteInfoBean.java 2gnmk TyF  
*/ K9(Su`zr  
package NetFox; ^sA"&Vdr^  
R8<'m
 
f~NGIlgR  
public class SiteInfoBean { p:n.:GZ=y  
EsR$H2"  
'6&a8&:  
private String sSiteURL; //Site's URL 9s}y*Vp  
private String sFilePath; //Saved File's Path BCtm05  
private String sFileName; //Saved File's Name j\S}TaH0e  
private int nSplitter; //Count of Splited Downloading File };=44E'7  
CnA
0^JX  
AT%@T|  
public SiteInfoBean() -I\Y m_)  
{//nSplitter的缺省值为5 (ug^2WG Yq  
//default value of nSplitter is 5 Htu}M8/4  
this("","","",5); oTqv$IzqP  
} )KPQ8y!d  
)D1=jD(  
x.OCE`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) t$W~X~//  
{ R%Y#vUmBV{  
sSiteURL= sURL; ;.<0lnV  
sFilePath = sPath; aJi0!6oy  
sFileName = sName; 9M&uQccY  
this.nSplitter = nSpiltter; qrtA'fU  
WKB8k-.]ww  
}dt7n65  
} 6-\g
hPo  
Fl'+ C   
sC=fXCGW\p  
public String getSSiteURL() #nS  
{ j>70AE3[8  
return sSiteURL; ~20O&2  
} 3LaqEj  
/?,c4K,ap  
&XnbZ&_  
public void setSSiteURL(String value) %wYGI  
{ .s)z
?31  
sSiteURL = value; 5#SD$
^  
} I2$.o0=3Y  
e+t2F |xDh  
gVs8W3GW  
public String getSFilePath() g}\Yl.  
{ ,?Bo x  
return sFilePath; ~A5MzrvIO2  
} s$s]D\N  
eviv,  
.jfkOt?2  
public void setSFilePath(String value) _ IqUp Y  
{ B.-1wZl  
sFilePath = value; i!!1^DMrw  
} Nd"4*l;
 
cF7efs8u  
lQolE P.pc  
public String getSFileName() zu~E}  
{ wSMP^kG  
return sFileName; /5y*ZIq]e  
} &u_s*  
b:,S  
D6KYkN(,v  
public void setSFileName(String value) Gg3cY{7  
{ ~HH#aXh*  
sFileName = value; n2JwZ?  
} (\QkXrK  
0m|$ vb  
W\tSXM-Hg  
public int getNSplitter() HktvUJ(Ii  
{ -|l^- Qf!  
return nSplitter; Q[+o\{ O  
} x-:a5Kz!  
V*m@Rs!)2  
G@O~*k1v  
public void setNSplitter(int nCount) WzC_M>_  
{ IfH*saN7  
nSplitter = nCount; ].j;d2xT\  
} KKz{a{ePY%  
} j5,vSh~q;'  
ItZqLUJm  
Fnnk}I}  
/* 1%?J l~M  
**Utility.java pD+_ K  
*/ a/Cd;T2  
package NetFox; .7ZV:m  
k|^e=I   
m{/?6h 1  
public class Utility { b|cUKsL5  
ng-g\&-  
z4snH%q  
public Utility() V'";u?h#S  
{ |g3a1El  
F0O/SI(cA  
a|*{BlY  
} ov{  
uIG,2u,  
//线程睡眠 rI\G&OqpP  
public static void sleep(int nSecond) 6dRxfbL  
{ F9sVMV
 
try{ +[MzF EE[  
Thread.sleep(nSecond); <mm.b  
} ^MyuD?va  
catch(Exception e) M>pcG.6V  
{ `Ns$HV  
e.printStackTrace (); ZYy,gu<  
} Q)\~=/Lb  
} y^o*wz:D*  
bIR AwktD  
//日志 Q1f
J`A=  
public static void log(String sMsg) q F\a]e  
{ 7j&iHL  
System.err.println(sMsg); #|\NG  
} nV|H5i;N7  
eB`7C"Z  
K[%)_KW  
public static void log(int sMsg) ,DN>aEu1  
{ ;TAf[[P  
System.err.println(sMsg); HQ8oOn
 
} nQ/R,+6h  
} fh0a "#L{  
8._ A[{.f  
L#Mul&r3x0  
/* 2L#$WuM~^  
**TestMethod.java LRqBP|bjCD  
*/ U2=PmS P  
package NetFox; t;7 tuq   
v-;j44sB  
p#VA-RSUQ|  
public class TestMethod { vI<n~FHt  
,4bqjkX5q  
"T`Q,  
public TestMethod() <q V<dK&W  
{ ///xx/weblogic60b2_win.exe 28KS*5S  
try{  a=<l}`*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); XwKB+Yj0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }u=-Y'!#]  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  6j FD|  
fileFetch.start(); -lKk.Y.}r  
} L'dR;T[;  
catch(Exception e){e.printStackTrace ();} ,)u\G(N  
7V6gT}R  
RT2%)5s  
} /bE=]nM  
>tfy\PY:  
%!5[3b'h  
public static void main(String[] args) i1qhe?5  
{ IXp(Aeb  
new TestMethod(); qVOlUH  
} ?mdgY1  
} "~y@rqIba  
点击下载更多相关资料