http断点续传简单实现（java)

/* z>#$#:Z4  
**SiteFileFetch.java *VAi!3Rx;  
*/ "@bk$o=  
package NetFox; b<MMli  
import java.io.*; os+wTUR^  
import java.net.*; dKG<"
 
j>=".^J  
b8Ad*f\  
public class SiteFileFetch extends Thread { `l@t3/  
h.%Qn vL  
: .e
S|  
SiteInfoBean siteInfoBean = null; //文件信息Bean *J-jr8&  
long[] nStartPos; //开始位置 ::t!W7W  
long[] nEndPos; //结束位置 PU\q.y0R  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #!<s& f|O  
long nFileLength; //文件长度 TV2:5@33  
boolean bFirst = true; //是否第一次取文件 a.ME{:a%  
boolean bStop = false; //停止标志 nsn,8a38  
File tmpFile; //文件下载的临时信息 g)Uh   
DataOutputStream output; //输出到文件的输出流 V#FLxITk  
 +PD5pr  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） XX;%:?n  
public SiteFileFetch(SiteInfoBean bean) throws IOException rV{e[fGd  
{ N1+]3kt ~  
siteInfoBean = bean; G4]``  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ?["ZE
a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); unB "dE  
if(tmpFile.exists ()) XX+rf  
{ 'Pn`V{a  
bFirst = false; UzRF'<TWf  
read_nPos(); v:ZD}Q_  
} Lg53 Ms%  
else Zz ?y&T  
{ x@x@0k`A2  
nStartPos = new long[bean.getNSplitter()]; :\cJvm  
nEndPos = new long[bean.getNSplitter()]; [r~lO@  
} 4iPg_+  
{=Y&q~:8v  
CF4y$aC#  
7m$/.\5  
} e1a%Rj~  
U%olH >1K  
[C#pMLp,~  
public void run() =1uI >[aN  
{ n*|-"'j  
//获得文件长度 Fs~-exY1  
//分割文件 "R]K!GUU  
//实例FileSplitterFetch `hhG^O_  
//启动FileSplitterFetch线程 u-<s@^YG  
//等待子线程返回 L~zet-3UNf  
try{ J)+eEmrU  
if(bFirst) +d15a%^`  
{ !pXz-hxKT  
nFileLength = getFileSize(); (\_d'Js(;  
if(nFileLength == -1) r +fzmb  
{ 3sNq3I  
System.err.println("File Length is not known!"); [\p0eUog/  
} hWJc A.A  
else if(nFileLength == -2) N:zSJW`1  
{ 1 ErYob.p  
System.err.println("File is not access!"); y->iv%
 
} h Nw
b.[  
else %dQX d]  
{ w,$17+]3  
for(int i=0;i<nStartPos.length;i++) @ vudeaup  
{ S^.=j oI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); YEj U3^@  
} 'LI)6;Yc  
for(int i=0;i<nEndPos.length-1;i++) Plv+mb  
{ w9BH>56/"  
nEndPos = nStartPos[i+1]; h)8_sC  
} ^6n]@4P  
nEndPos[nEndPos.length-1] = nFileLength; cPYQ<Y=  
} lUz@
Em  
} Li^V?  
XDQ1gg`  
`z.#O\@o  
//启动子线程 _XtY/7n  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <k1gc
,*  
for(int i=0;i<nStartPos.length;i++) 4 n(
f/  
{ %mJ)pMV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T@Xi
G:b7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4#uoPkLK  
nStartPos,nEndPos,i); o%iTYR:x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !{LwX
 Kf  
fileSplitterFetch.start(); PGDlSB^O  
} k[m-"I%ZFX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #Ba'k6b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Y_B(R  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", j.*}W4`Q_  
nEndPos = " + nFileLength); G_@H:4$3  
// fileSplitterFetch[nPos.length-1].start(); \~>#<@h  
UK/k?0  
C09@2M'  
//等待子线程结束 d0d2QRX  
//int count = 0; YVi]f2F%  
//是否结束while循环 AnQRSB
(  
boolean breakWhile = false; #e[5O|V~  
P[~a'u  
MaM7u:kD#  
while(!bStop) *,u{~(thR  
{ n_j[hA  
write_nPos(); }ls>~uN  
Utility.sleep(500); .u&g2Y  
breakWhile = true; 5q[@N J  
N 2\,6<  
Q]C1m<x  
for(int i=0;i<nStartPos.length;i++) ijfT!W  
{ K[H$qJmPX  
if(!fileSplitterFetch.bDownOver) Hl51
R"8o  
{  R !HL+  
breakWhile = false; j~0hAKHG  
break; z#b6 aP  
} d!cx%[  
} li?Gb1  
if(breakWhile) GzX@Av$  
break; S6uBk"V!  
O #"O.GX<  
$oz ZFvJF  
//count++; VPuzu|  
//if(count>4) \}5\^&}_  
// siteStop(); Wk?XlCj  
} ZZUCwczI  
uWSG+  
(Y86q\DQ?|  
System.err.println("文件下载结束！"); fsu'W]f  
} ]v#Q\Q8>  
catch(Exception e){e.printStackTrace ();} mb/Y  
} tfO _b5g  
.+.Pc_fv  
Im2g2]  
//获得文件长度 ]4PG[9J@  
public long getFileSize() 0T*jv! q>  
{ w$_ooQ(_;Q  
int nFileLength = -1; BTB,a$P/  
try{ 6k-]2,\#  
URL url = new URL(siteInfoBean.getSSiteURL()); n:{yri+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \VW.>@s~  
httpConnection.setRequestProperty("User-Agent","NetFox"); \%#jT GFs~  
;,D7VxWhY  
\I>,j,c  
int responseCode=httpConnection.getResponseCode(); YB[P`Muj  
if(responseCode>=400) LS;kq',  
{ Y) Z>Bi  
processErrorCode(responseCode); };
|'8'5  
return -2; //-2 represent access is error *ZHk^d:  
} 0z.&  
7ORwDR,`5  
B; ~T|exu  
String sHeader; z[B7k%}  
fE >FT9c  
`#~@f!';  
for(int i=1;;i++) 7J)-WXk  
{ >PTq5pk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =
d9%ce  
//Utility.log(in.readLine()); J?{uG8)  
sHeader=httpConnection.getHeaderFieldKey(i); ?U&o
nGy  
if(sHeader!=null) Xa36O5$4]9  
{ j&F&wRD%r  
if(sHeader.equals("Content-Length")) 'n\ZmG{  
{ l ^{]pD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u >x2  
break; R]dc(D  
} 3.soCyxmc  
} sf%=q$z  
else C)`/Q(^  
break; M C>{I3  
} L_/.b%0)  
} Mb-C DPT  
catch(IOException e){e.printStackTrace ();} tU
zuel*  
catch(Exception e){e.printStackTrace ();} 3N?uY2  
#+XKfumLk  
Yk }zN_v  
Utility.log(nFileLength); I;=}@]9  
Da.vyp  
uu HWN|  
return nFileLength; 3?C$Tl2G8  
} >LLFe~9`g  
qr:[y  
s:M:Ff  
//保存下载信息（文件指针位置） H}A67J9x  
private void write_nPos() Oa{M9d,l  
{ 'EXp[*  
try{ I\":L  
output = new DataOutputStream(new FileOutputStream(tmpFile)); kIQMIL0+  
output.writeInt(nStartPos.length); Xf
:-K(%e  
for(int i=0;i<nStartPos.length;i++) }ZV$_  
{ 4!D!.t~r  
// output.writeLong(nPos); o)w'w34FCT  
output.writeLong(fileSplitterFetch.nStartPos); {jbOcx$t  
output.writeLong(fileSplitterFetch.nEndPos); =VDN9-/.  
} M^H357r%  
output.close(); (u
e;O~  
} /6g*WX2P1  
catch(IOException e){e.printStackTrace ();} 5<9}{X+@o  
catch(Exception e){e.printStackTrace ();} ?'^xO:  
} oA`Ncu5  
azN<]u@.  
LFtnSB8  
//读取保存的下载信息（文件指针位置） N"T+. r  
private void read_nPos() hD sFsG  
{ 6*CvRb&  
try{ 2: fSn&*/>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (T,ST3{*k  
int nCount = input.readInt(); IU&n!5d$)|  
nStartPos = new long[nCount]; pX"f "  
nEndPos = new long[nCount]; s %/3X\_  
for(int i=0;i<nStartPos.length;i++) y "gYv  
{ GDhg VOW(  
nStartPos = input.readLong(); x-cg df  
nEndPos = input.readLong(); -K PbA`j+  
} TEv3;Z*N  
input.close(); %<P&"[F]v@  
} 0D=6-P?^W  
catch(IOException e){e.printStackTrace ();} &!_>J0  
catch(Exception e){e.printStackTrace ();} nD|Bo 9  
} ?z p$Wz;k  
(;\JCeGA  
{o AJL  
private void processErrorCode(int nErrorCode) o[aRG7C  
{ t '* L,  
System.err.println("Error Code : " + nErrorCode); XNsMXeO]&  
} p%8y!^g  
/ F9BbG{  
V4iN2  
//停止文件下载 WUZusW5s  
public void siteStop() cJGU~\  
{ bvi Y.G3  
bStop = true; EQ\/I( =l  
for(int i=0;i<nStartPos.length;i++) =56O-l7T*w  
fileSplitterFetch.splitterStop(); ELPzqBI  
6ID@0  
l.El3+  
} Sw%^&*J  
} C,&r7  
//负责部分文件的抓取 FZO}+ P  
**FileSplitterFetch.java U%_BgLwy%  
*/ \\xoOA.  
package NetFox; k,OP*M  
DOyYy~Q  
s&TPG0W  
import java.io.*; AKu]c-  
import java.net.*; Igrr"NuDZ  
b
dP @^Q  
a/^ojn  
public class FileSplitterFetch extends Thread { PF~w$ eeQ  
Bz!SZpW(M  
Gg$4O
8  
String sURL; //File URL 3vepJ)D (  
long nStartPos; //File Snippet Start Position SN'j?-  
long nEndPos; //File Snippet End Position D.su^m_1  
int nThreadID; //Thread's ID M*<Ee]u  
boolean bDownOver = false; //Downing is over AhWcJD]  
boolean bStop = false; //Stop identical \W4|.[  
FileAccessI fileAccessI = null; //File Access interface @vs+)aRa  
xim'TVwvC  
plN:QS$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C/_Z9LL?F  
{ ?)X0l  
this.sURL = sURL; lf-1;6nyk"  
this.nStartPos = nStart; *:}9(8d  
this.nEndPos = nEnd; K!g!tA$  
nThreadID = id; :"{("!x  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 eaB6e@]@  
} N3"O
#C  
Vq4g#PcG  
OiI29  
public void run() Ku$:.  
{ >{
R+j4%  
while(nStartPos < nEndPos && !bStop) *sz:c3{_  
{ |$  
*5m4j=-  
Z}$wvd  
try{ m?GBvL$  
URL url = new URL(sURL); M-7^\wXTA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !-B$WAV  
httpConnection.setRequestProperty("User-Agent","NetFox"); NAgm?d  
String sProperty = "bytes="+nStartPos+"-"; ecvQEK2L  
httpConnection.setRequestProperty("RANGE",sProperty); hX4V}kj  
Utility.log(sProperty); E7mB=bt>=  
O
N [
F  
`cgyiJ  
InputStream input = httpConnection.getInputStream(); sYa;vg4[  
//logResponseHead(httpConnection); p.)IdbC`B  
[+;>
u|  
mH6\8I  
byte[] b = new byte[1024]; x<d2/[(}mT  
int nRead; ~'lYQ[7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8GlRO4yd  
{ pd^"MG  
nStartPos += fileAccessI.write(b,0,nRead); ;2N: =Rv  
//if(nThreadID == 1) mM(Z8PA9-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [$]qJ~kz  
} @}\wec_  
6
9+Pf*  
Xnc?o
T+  
Utility.log("Thread " + nThreadID + " is over!"); }-/oL+j  
bDownOver = true; 0(qtn9;=2  
//nPos = fileAccessI.write (b,0,nRead); 0fE?(0pBj  
} yd|ao\'=  
catch(Exception e){e.printStackTrace ();} yi.GD~69  
} SR>(GQ,m0;  
} Ky[s&>02  
N||a0&&  
lq}m0}9<  
//打印回应的头信息 vFwhe
!  
public void logResponseHead(HttpURLConnection con) _kEU=)Xe  
{ me@k~!e"z  
for(int i=1;;i++) :6TLT-B  
{ [[s^rC<d  
String header=con.getHeaderFieldKey(i); ,eSII2,r4  
if(header!=null) ,,8'29yEq  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #kQ1,P6,(  
Utility.log(header+" : "+con.getHeaderField(header)); >lkjoEVQ  
else /JjSx/  
break; YgV"*~  
} ,8@q2a/  
} %t*KP=@  
#KUNZW  
XcFu:B  
public void splitterStop() weH;,e*r  
{ N1fPutl$a
 
bStop = true; lK Ry4~O  
} VPvQ]}g6k  
4OOI$J$Jh  
ech1{v\B|  
} U{52bH<  
AB+HyZ*//  
0d/ f4  
/* ?Gx-q+H  
**FileAccess.java U+G8Hs/y  
*//文件访问(定位，写) ovk^  
package NetFox; M#}k@ ;L3  
import java.io.*; T&ib]LmR  
sjy/[.4-  
OE/r0C<&  
public class FileAccessI implements Serializable{ ,5& Rra/  
wd*V,ZN7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 h9Tst)iRi  
RandomAccessFile oSavedFile; e'X"uH Xt.  
long nPos; XyYP!<].C  
o*5b]XWw  
{W'{A  
public FileAccessI() throws IOException NCp]!=uM;  
{ (j&7`9<5  
this("",0); f?lnBvT|b  
}
+2#pP  
&ox5eX(  
S
oHw9FtS  
public FileAccessI(String sName,long nPos) throws IOException a(_3271  
{ th|'t}bWV  
oSavedFile = new RandomAccessFile(sName,"rw"); )1/J5DI @8  
this.nPos = nPos; _};T:GOT  
oSavedFile.seek(nPos); F;ELsg  
} J9&#);(  
awgS5We|  
=>*9"k%m  
public synchronized int write(byte[] b,int nStart,int nLen) $Yj4&Two<  
{ *5mJA -[B+  
int n = -1; T5eJIc3a"  
try{ H,(4a2zx  
oSavedFile.write(b,nStart,nLen); LHMA-0$?)  
n = nLen; u}-)ywX  
} v*&WqVg  
catch(IOException e) Va$JfWef  
{
s+9b.  
e.printStackTrace (); 0Wb3M"#9<  
} Tffdm  
yK>s]65&  
>mMmc!u>G  
return n; V9;O1  
} ;F:Qz^=.a  
ejpSbVJ  
Bgs,6:  
} ~}Z'/zCZf  
r12e26_Ab  
2{01i)2y  
/* oz'^.+uvE  
**SiteInfoBean.java m }\L i]  
*/ 7#sb},J{  
package NetFox; ^ux"<?  
OSkBBo]~z  
gmCB4MO  
public class SiteInfoBean { e0g>.P@6  
'ALe>\WO  
r5Xi2!  
private String sSiteURL; //Site's URL 4Y{&y6  
private String sFilePath; //Saved File's Path ^}4ysw  
private String sFileName; //Saved File's Name -^,wQW:o)  
private int nSplitter; //Count of Splited Downloading File G3D!ifho.#  
qb PC5v  
<-xu
*Fc  
public SiteInfoBean() +ooQ-Gh  
{//nSplitter的缺省值为5 cJ#%OU3p  
//default value of nSplitter is 5 lT+N{[kLt*  
this("","","",5); R 5Cy%  
} 8O.5ML{  
`cqZ;(^  
J1d|L|M  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &Ui&2EW  
{ &P(vm@*  
sSiteURL= sURL; 9=G dj!L  
sFilePath = sPath; *cc|(EM  
sFileName = sName; Ip*[H#h  
this.nSplitter = nSpiltter; :i]g+</  
Cgn@@P5ZC  
|dqv
v  
} 1A{iUddR  
QW>(LGG=  
C44*qiG.  
public String getSSiteURL() ^ =RSoR  
{ O;RNmiVoq  
return sSiteURL; '?b.t2  
} 8zH/a   
g&L $5  
}\d3   
public void setSSiteURL(String value) $F~hL?"?  
{ UY&DX
IPM  
sSiteURL = value; (=w ff5U  
} ,CjJO -  
hJ0m;j&4y  
fZt3cE\  
public String getSFilePath() &:Sb$+z  
{ K9Bi2/N  
return sFilePath; #*;Nb  
} l(
?Yx  
UdX aC= Q  
OuU]A[r  
public void setSFilePath(String value) ?r}!d2:dX  
{ E']Gh  
sFilePath = value; i ,g<y  
} 6|{uZNz  

ATf{;S}  
W'<cAg?  
public String getSFileName() ?p!+s96  
{ KDy:A>_ G"  
return sFileName; W'M\DKJ?  
} fSzX /r  
{bPcr hB  
TkV$h(#!f&  
public void setSFileName(String value) OvW/{  
{ bHH=MLZR:  
sFileName = value; .@;,'Xw1~  
} >jBnNA@  
o!M*cyq  
AZ
adNuL/  
public int getNSplitter() T#w *5Qf  
{ w\3'wD!  
return nSplitter; 7`6JK  
} Id'@!U:NA  
ti9cfv>  
!Y
EU<9  
public void setNSplitter(int nCount) G/C5o=cY  
{ g@7j<UY  
nSplitter = nCount; =Pgu?WU@  
} @DYkWivLu  
} m1lfC  
YP vg(T  
Y&_1U/}h  
/* blA]z!FU  
**Utility.java L8j#lu  
*/ N^8 lfc$a  
package NetFox; 6Bfu89  
IWcYa.=tZ  
},5
_h0  
public class Utility { ^,KN@  
Q.[^5 8  
#%g~fh  
public Utility() CmPix]YMQ  
{ ICgyCsZ,  
$\@yH^hL  
"Z6:d"S`  
} t#h<'?\E  
$MG. I[h  
//线程睡眠 `;R|SyrX  
public static void sleep(int nSecond) RU'DUf  
{ 6axmH~_  
try{ C&ivjFf  
Thread.sleep(nSecond); v`$9;9  
} u!DSyHR '  
catch(Exception e) X*'-^WM6  
{ ~ ]q^Akq  
e.printStackTrace (); W[3)B(Vq<E  
} kM\O2ay  
} tEl4 !vA  
lYu1m  
//日志 GX lFS#`  
public static void log(String sMsg) 'yM)>]u"  
{ mckrR$>  
System.err.println(sMsg); 8}W06k>)%  
} :1wMGk  
?y{C"w!   
s:/.:e_PU  
public static void log(int sMsg) , eZL&n  
{ @kKmkVhu*  
System.err.println(sMsg); ]-aeoa#  
} oa?
e
K  
} $V)LGu2(m  
[y T4n.f  
b
MD'teJ  
/* ^9UF Pij"  
**TestMethod.java >9g`9hB  
*/ pTK|u!fs  
package NetFox; TPds)osZT  
,&HZvU&  
^"%SHs  
public class TestMethod { t=]&q.  
FZ/l T-"  
RfwTqw4@  
public TestMethod() sy`:wp  
{ ///xx/weblogic60b2_win.exe #7U,kTj9  
try{ $E4W{ad2jW  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); MNiu5-g5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); p\8
cl/~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \6Ze H  
fileFetch.start(); J7.bFW'  
} 1h+!<c q  
catch(Exception e){e.printStackTrace ();} GfU+'k;9  
G1~|$X@@  
k[
Iwxl;/  
} fwRlqfi  
L/GM~*Xp(O  
<P5;8  
public static void main(String[] args) q9oF8&O,  
{ WL}6YSC  
new TestMethod(); =D4E
PfQn1  
} LZG^\c$  
} v-)e
T  
点击下载更多相关资料