http断点续传简单实现（java)

/* g'<ekY+V:  
**SiteFileFetch.java $e/[!3CASP  
*/ GI[XcK^*w  
package NetFox; `\M}~  
import java.io.*; b6ui&Y8z  
import java.net.*; ,4Qct=%L_  
:#nv:~2]  
PsOu:`=r  
public class SiteFileFetch extends Thread { h%+6y  
^/:G`'  
4fgYO]  
SiteInfoBean siteInfoBean = null; //文件信息Bean %=<Kb\  
long[] nStartPos; //开始位置 `#y?:s]e  
long[] nEndPos; //结束位置 ;Vlt4,s)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [`_-;/Gx2  
long nFileLength; //文件长度 ?a{es!  
boolean bFirst = true; //是否第一次取文件 7Ug^aA  
boolean bStop = false; //停止标志 dW} m44X  
File tmpFile; //文件下载的临时信息 y8/+kn +  
DataOutputStream output; //输出到文件的输出流 g>;u} +lO  
w)Wg 8  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）
i_ z4;%#?  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2e*"<>aeq  
{ f;cY&GC  
siteInfoBean = bean; c7f11N!v>b  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]Z=O+7(r  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ! ~3zp L  
if(tmpFile.exists ()) "S^""5  
{ V2/?1  
bFirst = false;  K>S:Z  
read_nPos(); Y9ipy_@_?  
} bO6LBSZx]  
else i=aK ?^+  
{ xk@fBa }  
nStartPos = new long[bean.getNSplitter()]; rlP?Uh  
nEndPos = new long[bean.getNSplitter()]; ~pG,|\9  
} \ ix&
U  
;^9y#muk  
!rPU5y*  
/6Olq6V  
} a~Nh6 x  
U^Ulj/%6  
`2PvE4]%p  
public void run() aZB$%#'vR  
{ o@W:PmKW  
//获得文件长度 T.GB*  
//分割文件 ,!Q^"aOT:  
//实例FileSplitterFetch j@C*kj;-  
//启动FileSplitterFetch线程 ]mdO3P  
//等待子线程返回 ?CO..l  
try{ [
a!*m<  
if(bFirst) z!>ml3  
{ Rr"D)|Y;C(  
nFileLength = getFileSize(); :WHbwu,L$  
if(nFileLength == -1) `ZZq Sc4  
{ 0.lOSAq  
System.err.println("File Length is not known!"); #{x4s?  
} oa2v/P1`  
else if(nFileLength == -2) /@feY?glc  
{ &)GlLpaT  
System.err.println("File is not access!"); P)rz%,VF+  
} _t.Ub:  
else M~LYq
  
{ ;'P<#hM[$  
for(int i=0;i<nStartPos.length;i++) ]JvZ{fA%*  
{ *Y<1KXFU  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _>4Qh#6K  
} @zi_@B  
for(int i=0;i<nEndPos.length-1;i++) tr-muhuK  
{ Dh.pH1ZY3n  
nEndPos = nStartPos[i+1]; Eq6. s)10  
} <= Aqi91  
nEndPos[nEndPos.length-1] = nFileLength;  LAO2Py#  
} GjeRp|_Qd<  
} VK3e(7b  
Yu_` >so  
rO7[{<97m  
//启动子线程 i8i~b8r]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; O~&j}WN  
for(int i=0;i<nStartPos.length;i++) _ Y8jl,J  
{ J*m~fZ^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8c5%~}kG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), U~s-'-C/  
nStartPos,nEndPos,i); +?bjP6w_g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z,IUCNgM  
fileSplitterFetch.start(); H:!pFj  
} 4$MV]ldUI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,@r 0-gL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'q, L*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !B:wzb_  
nEndPos = " + nFileLength); +MvO+\/  
// fileSplitterFetch[nPos.length-1].start(); Rn5{s3?F~2  
YW'l),Z  
{LoNp0i1a  
//等待子线程结束 *4?%Y8;bF6  
//int count = 0; 5%;=(Oig  
//是否结束while循环 N5|wBm>m  
boolean breakWhile = false; XG;Dj<Dm  
|[/'W7TV%?  
f&88N<)  
while(!bStop)
@r9[&  
{ GRj#1OqL  
write_nPos(); IXof-I%8  
Utility.sleep(500); @lTd,V5f  
breakWhile = true; jV~+=(w)  
bm#/ KT_8  
Yrmd hSY  
for(int i=0;i<nStartPos.length;i++) PIZK*Lop  
{ KAR **Mp+  
if(!fileSplitterFetch.bDownOver) #s
3R4@{  
{ {^_K  
breakWhile = false; A? T25<}  
break; erd
A?  
} $[{YE[a  
} bguTWI8bk  
if(breakWhile) prO
~g  
break; IUSV\X9  
j+NsNIJq  
-mqL[ h,  
//count++; W~d^ *LZt  
//if(count>4) 3fdqFJ O  
// siteStop(); w'zSV1  
} R-OQ(]<*  
;kR+jC(  
U_<k*o@
:  
System.err.println("文件下载结束！"); Da&Brm  
} 2"8qtG`Et  
catch(Exception e){e.printStackTrace ();} ` 3h,Cy^  
} Zx U?d   
jWcfQ  
Z^6qxZJ7  
//获得文件长度 33OkYC%
e  
public long getFileSize() ]3I@5}5%  
{ JlhI3`X;/  
int nFileLength = -1; uh&Qdy!I  
try{ cNiNLwc  
URL url = new URL(siteInfoBean.getSSiteURL()); [,Fu2j]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ob@HzXH  
httpConnection.setRequestProperty("User-Agent","NetFox"); n7(/ml+Q_  
?#Y1E~N  
"mB /"  
int responseCode=httpConnection.getResponseCode(); K-4o_:F  
if(responseCode>=400) oN&U@N/>aU  
{ JGQ)/(  
processErrorCode(responseCode); ,)Z1&J?  
return -2; //-2 represent access is error rHJtNN8$k  
} O1Nya\^g<I  
_E8doV  
iG+=whvL  
String sHeader; uL |O<  
FC#t}4as  
1!&m1  
for(int i=1;;i++) gIY]hC.  
{ xew s~74L  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !n|4w$t"V  
//Utility.log(in.readLine()); "J>8ZUP  
sHeader=httpConnection.getHeaderFieldKey(i); 'DTq<`~?  
if(sHeader!=null) {)PgN  
{ DTz)qHd#X  
if(sHeader.equals("Content-Length")) ]BaK8mPl  
{ tb;u%{S  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {;+9A}e  
break; l\HtP7]  
} ->`R[k  
} lX/:e=  
else U[|o!2$  
break; 2 sK\.yS  
} mO&zE;/[  
} `2,F!kCt  
catch(IOException e){e.printStackTrace ();} d/lV+yZ  
catch(Exception e){e.printStackTrace ();} Ti&v9re%wO  
`ZGKM>q`  
jPEOp#C  
Utility.log(nFileLength); ^b6yN\,S  
Lrqe:\  
d'[]  
return nFileLength; _:+ k|I  
} b}J,&eYD  
"z4V@gk  
ASUleOI79(  
//保存下载信息（文件指针位置） !#dp[,nk  
private void write_nPos() qKk|2ecTB5  
{ !YIW8SP)  
try{ 91M5F$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); W~Q;R:y  
output.writeInt(nStartPos.length); WT jy"p*  
for(int i=0;i<nStartPos.length;i++) |Q$9I#rv  
{ e`zCz`R  
// output.writeLong(nPos); Y7<
(_
p7  
output.writeLong(fileSplitterFetch.nStartPos); OPC8fX5.  
output.writeLong(fileSplitterFetch.nEndPos); {9-n3j}  
} nx
@,oC4  
output.close(); <ToRPx&E  
} [}`-KpV!;  
catch(IOException e){e.printStackTrace ();} DVjwY_nG7  
catch(Exception e){e.printStackTrace ();} jbp?6GW  
} 3u[5T|D'  
a LJ d1Q
 
c+501's  
//读取保存的下载信息（文件指针位置） q,>4#J[2;s  
private void read_nPos() q``
:[Sz  
{ .q|k459oi  
try{ uLSuY}K0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F~?|d0  
int nCount = input.readInt();  bU$M)  
nStartPos = new long[nCount]; I-m Bj8^;  
nEndPos = new long[nCount]; cFr`9A\-n  
for(int i=0;i<nStartPos.length;i++) wicW9^ik  
{ .,\^{.E  
nStartPos = input.readLong(); =Y5_@}\0  
nEndPos = input.readLong(); 7KN+ @6!x  
} dP=,<H#]m  
input.close(); Zu/w>  
} d fSj= 4  
catch(IOException e){e.printStackTrace ();} #@J{ )  
catch(Exception e){e.printStackTrace ();} MzE1he1  
} X=V2^zrt  
7sU,<Z/D  
P DwBSj  
private void processErrorCode(int nErrorCode) '<xV]k|v  
{ 'cA(-ghY/E  
System.err.println("Error Code : " + nErrorCode); =3EjD;2  
} DA>TT~L  
f<M!L>+M6  
pd-I^Q3-  
//停止文件下载 |q c<C&O  
public void siteStop() !o\e/HGc!  
{ Ll, U>yo  
bStop = true; >fzFNcO*  
for(int i=0;i<nStartPos.length;i++) ANTWWs}  
fileSplitterFetch.splitterStop(); v^B2etiX_  
6eb~Z6n&?  
5]K2to)>`  
} b8!   
} b-RuUfUn0  
//负责部分文件的抓取 vbfQy2q  
**FileSplitterFetch.java k:URP`w[X=  
*/ 0wt4C% .0  
package NetFox; ~ 1~|/WG  
73JrK_h  
1Cw HGO  
import java.io.*;
F>eo.|'  
import java.net.*; B+MnT{  
/!fJ`pu!  
xNjWo*y v  
public class FileSplitterFetch extends Thread { ?}#Iu
-IA  
k; >Vh'=X  
4hzdc] a  
String sURL; //File URL }ld^zyL  
long nStartPos; //File Snippet Start Position T3@34}*  
long nEndPos; //File Snippet End Position /0Mt-8[  
int nThreadID; //Thread's ID IyAD>Q^  
boolean bDownOver = false; //Downing is over J,\e@  
boolean bStop = false; //Stop identical =|dHD  
FileAccessI fileAccessI = null; //File Access interface ^bq,+1;@Q  
{nw.bKq7  
"28zLo3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException wo;OkJKF  
{ sKk+^.K}|  
this.sURL = sURL; v-wZHkdd1  
this.nStartPos = nStart; p(nEcu  
this.nEndPos = nEnd; Hbn78,~.  
nThreadID = id; k5Su&e4]]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Cj$:TWYIh[  
} '_5|9 }  
hzT)5'_  
g>l+oH[Tv|  
public void run() zrf tF2U  
{ "Q{l])N  
while(nStartPos < nEndPos && !bStop) ]LEaoOecu  
{ >GLoeCRNu  
0Ua=&;/2  
J4@-?xj=\q  
try{ 4-I7"pW5  
URL url = new URL(sURL); Ubgn^+AI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O<E8,MCA[a  
httpConnection.setRequestProperty("User-Agent","NetFox"); .(3ec/i4CF  
String sProperty = "bytes="+nStartPos+"-"; tG ZMIG_  
httpConnection.setRequestProperty("RANGE",sProperty); vPc*x5w-  
Utility.log(sProperty); K$w;|UJc  
Qqx!'
fft  
dMCoN8W  
InputStream input = httpConnection.getInputStream(); EiG5k.C@  
//logResponseHead(httpConnection); `WnsM;1Y"  
~Z!YB,)bp  
x,zYNNx5g  
byte[] b = new byte[1024]; WIuYSt)h  
int nRead; gS8+S\2
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %M))Ak4~a  
{ ;<_a ,5\Q  
nStartPos += fileAccessI.write(b,0,nRead); HUAYtUBH  
//if(nThreadID == 1) esj6=Gh  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ifu!6_b.  
} *ra>Kl0   
GdY@$&z{i  
maN2(1hz  
Utility.log("Thread " + nThreadID + " is over!"); >]_^iD]*t  
bDownOver = true; l1KgPRmEP  
//nPos = fileAccessI.write (b,0,nRead); 841y"@*BY  
} AI Kz]J0;  
catch(Exception e){e.printStackTrace ();} 9 M%Gnz  
} a2tEp+7?  
} &pjj
 
C#^y{q  
[0aC]XQZ  
//打印回应的头信息 g(;OUkj$Zp  
public void logResponseHead(HttpURLConnection con) w;j<$<4=7  
{ =B5{7g\  
for(int i=1;;i++) 4dcm)Xr  
{ 6@t&  
String header=con.getHeaderFieldKey(i); /t`\b [  
if(header!=null) k sXQ}BE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0c`nk\vUy  
Utility.log(header+" : "+con.getHeaderField(header)); $#p5B
QQ|  
else T!ZjgCY}  
break; {it}\[3  
} >}%#s`3W1_  
} BQ)>}YHk  
_+NjfF|  
Qrg- xu=  
public void splitterStop() $ P5K  
{ {59>U~  
bStop = true; "a(4])  
}  1n +Uv*  
I;%1xdPt  
yxHo0U  
} BDvkY  
#dL,d6a  
/51$o\4S  
/* d"06 gp  
**FileAccess.java ]xHiy+  
*//文件访问(定位，写) &K[sb%  
package NetFox; n qO*z<  
import java.io.*; &:&l+  
3qf#NJN}  
Z@Zg3AVU  
public class FileAccessI implements Serializable{ grzmW4Cw  
6qFzo1LO  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ch]Q
z[d  
RandomAccessFile oSavedFile; q,L>PN+W  
long nPos; w01[oU$
x=  
os"R'GYmf  
R}gdN-941  
public FileAccessI() throws IOException 5=I({=/>  
{ W+1nf:AI.  
this("",0); Y3DqsZ@  
} d{JI] !  
N=Ct3  
m(U.BXo  
public FileAccessI(String sName,long nPos) throws IOException EQ,`6UT>  
{ <q$Tk,  
oSavedFile = new RandomAccessFile(sName,"rw"); kD)31P  
this.nPos = nPos; F_'{:v1GW  
oSavedFile.seek(nPos); N^$q;%
 
} =o~+R\1ux+  
Q4-d|  
>IrQhSF  
public synchronized int write(byte[] b,int nStart,int nLen) jn|NrvrX  
{ e:nByzdH0[  
int n = -1; \O"H#gt  
try{ $I*}AUp v?  
oSavedFile.write(b,nStart,nLen); jyW={%&  
n = nLen; Mb2a;s  
} *sU,wa
X  
catch(IOException e) g$Y]{VM.J  
{ Ebs]]a>PO  
e.printStackTrace (); &,%n  
} 0SYJ*7lPX  
&?bsBqpN  
wi7Br&bGi  
return n; "=s}xAM|A  
} Xydx87L/-e  
`oikSx$vB.  
?%~p@  
} 51|s2+GG  
gPB=Z!  
\-]Jm[]^  
/* kR %,:   
**SiteInfoBean.java 4bGvkxZo`$  
*/ 5}hQIO&^%  
package NetFox; !Z2h?..O  
m}?jU  
/ojwOJ  
public class SiteInfoBean { dNf9,P_}  
ZrEou}z(*  
)J@[8 x`  
private String sSiteURL; //Site's URL u;nn:K1QFr  
private String sFilePath; //Saved File's Path + >dC  
private String sFileName; //Saved File's Name yOl
VS@7  
private int nSplitter; //Count of Splited Downloading File Ne|CWUhO  
?3fnt"  
Z1q<) O1QX  
public SiteInfoBean() [rcM32  
{//nSplitter的缺省值为5 8BAe6-*S8  
//default value of nSplitter is 5 2(GYk
 
this("","","",5); /'DAB**  
} 81|[Y'f  
XkqsL0\  
SHPDbBS  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ],!}&#|  
{ RjUrpS[I  
sSiteURL= sURL; Y54yojvV  
sFilePath = sPath; {wSz >,  
sFileName = sName; {f4jE#a
>v  
this.nSplitter = nSpiltter; SbUac<  
C~>0K,C0^  
>?JUGXAi'{  
} qmnl  
]]r;}$  
`dX0F=Ag?  
public String getSSiteURL() ux^rF  
{ Da[#X`Kp$  
return sSiteURL; VSUWX1k4%  
} u{uqK7]+  
MX#LtCG#V  
b
(HJ|  
public void setSSiteURL(String value) oc-&}R4=  
{ voRb>xF  
sSiteURL = value; `j
'1V1  
} 3dZj<(.
 
EY !o#m  

'tMD=MH  
public String getSFilePath() Y#9bM$x7  
{ 3hJ51=_0^  
return sFilePath; *7*cWO=  
} 1jzu-s,F  
0
r$n  
D{d%*hlI 3  
public void setSFilePath(String value) '?I3&lYz{  
{ N8x&<H  
sFilePath = value; y~OP9T
g  
} ^pY8'LF6  
@6!Myez'  
e+#k\x   
public String getSFileName() Xep2)3k>  
{ NuF?:L[  
return sFileName; @R;k@b   
} _I,GH{lhI  
NyC&j`d  
_ A{F2M  
public void setSFileName(String value) !w/fwOo  
{ EcytNYn  
sFileName = value; 7&jq  =  
} G[`2Nd<  
/`#JM  
qOQ8a:]?  
public int getNSplitter() f#I#24)RH  
{ =?]S8cth  
return nSplitter; b,jo94.G  
} 1x##b[LC  
G<rAM+B*g  
fV6ddh  
public void setNSplitter(int nCount) g%ys|  
{ X
N\rq=  
nSplitter = nCount; g#1Y4  
} 6N Ogi  
} Ed_Fx'  
&Wdi 5T8  
9G7Brs:  
/* W"t^t|H'~  
**Utility.java \j.l1O  
*/ |h/{qpsu  
package NetFox; V4n;N  
ESFJN}Q%0.  
~`$P-^u88X  
public class Utility { y>T>  
,E%O_:}R  
y GmFi  
public Utility() ?y"M>#  
{ NCo!n$O1~  
rAqS;@]0  
+.rOqkxJ  
} W|sU[dxZ  
~GJ;;v1b2  
//线程睡眠 U ){4W0  
public static void sleep(int nSecond) u35"oLV6}#  
{ nC?Lz1re  
try{ i;Kax4k  
Thread.sleep(nSecond); PAC=LQn&  
} b53s@7/mq  
catch(Exception e) E1w8d4P,G  
{ ,S`FxJcE  
e.printStackTrace (); tt6GtYrC 1  
} g"c7$  
} i]@k'2N  
@W==)S%O  
//日志 /+ais3  
public static void log(String sMsg) sK/ymEfRv  
{ 3Tw9Uc\vT  
System.err.println(sMsg); PJ<qqA`!  
} }!|$;3t+c  
n\BV*AH  
c7WOcy@M  
public static void log(int sMsg) $S2 /*  
{ tqpi{e  
System.err.println(sMsg); z_A\\  
} <y7Hy&&y-  
} TT#V'r\  
<F-IF7>a  
U17=/E  
/* n!Y}D:6c6  
**TestMethod.java 7xWJw  
*/ 7*WO9R/  
package NetFox; 8$IUit h  
W(-son~I  
%@q2  
public class TestMethod { M[-/&;`f@  
uFlf#t =  
wM-H5\9n  
public TestMethod() p=i6~   
{ ///xx/weblogic60b2_win.exe ;/IXw>O(/  
try{ J^PFhu  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N_+D#Z.g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); PB BJ.!Pb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $kkL)O*"]  
fileFetch.start(); YZ<5-C  
} *7L1SjZw  
catch(Exception e){e.printStackTrace ();} ,&* BhUC  
2<'ol65/c  
P^lzbWj^  
} \SYeDy  
0Xn,q]@Z  
k!6m'}v  
public static void main(String[] args) -0NkAQrg  
{ |}X[Yg=FG  
new TestMethod(); i;IhsKO0R  
} cqm:[0Xf5>  
} 8&qtF.i-6  
点击下载更多相关资料