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http断点续传简单实现(java)

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/* e hGC N=  
**SiteFileFetch.java Il[WXt<S  
*/ 3x$#L!VuU  
package NetFox; x-EAu 3=V  
import java.io.*; VzNH%  
import java.net.*; r,\(Y@I  
*+ayC{!  
pwQ."2x  
public class SiteFileFetch extends Thread { v?t+%|dzA  
0J B"@U&-  
n%hnL$!z  
SiteInfoBean siteInfoBean = null; //文件信息Bean vOU -bF%u  
long[] nStartPos; //开始位置 ?z.`rD$}(n  
long[] nEndPos; //结束位置 l K%Hb=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "5FeP;  
long nFileLength; //文件长度 37DvI&  
boolean bFirst = true; //是否第一次取文件 SJmri]4K  
boolean bStop = false; //停止标志 Si(?+bda0c  
File tmpFile; //文件下载的临时信息 }r[BME  
DataOutputStream output; //输出到文件的输出流 W*#/@/5  
jLU)S)  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) xFh}%mwpt[  
public SiteFileFetch(SiteInfoBean bean) throws IOException >U]. k8a)  
{ qx NV~aK  
siteInfoBean = bean; auU{I y   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /fEXAk  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Yy5F'RY  
if(tmpFile.exists ()) UKdzJEhG  
{ bL<cg tz7)  
bFirst = false; [DviN  
read_nPos(); *HUqW}_r  
} B:SRHd{*Wu  
else *&km5@*  
{ iQQJ`  
nStartPos = new long[bean.getNSplitter()]; q^)(p' X  
nEndPos = new long[bean.getNSplitter()]; nDfDpP&  
} ?M);wBe(  
(G Y`O  
/nNHI34  
J=Z"sU=  
} =>Efrma  
G9TUU.T  
 K!j2AP3  
public void run() Z(cgI5Pu  
{ VEk|lX;2  
//获得文件长度 .)Q'j94Q  
//分割文件 H}/1/5 L  
//实例FileSplitterFetch lH 8?IkK,g  
//启动FileSplitterFetch线程 CS  
//等待子线程返回 *^]ba>  
try{ idQr^{  
if(bFirst) OmW|\d PU  
{ u&:jQ:[  
nFileLength = getFileSize(); c|XnPqo;f  
if(nFileLength == -1) E^G=  
{ BRT2=}A  
System.err.println("File Length is not known!"); (pl OV)  
} 5 X rn]  
else if(nFileLength == -2) DuaOi1Gw  
{ 4 0eNgm^  
System.err.println("File is not access!"); J5-^@JYK  
} )!Bv8&;e  
else 2zAS \Y  
{ @W8RAS~  
for(int i=0;i<nStartPos.length;i++) 8GX@76o  
{ ;iWCV& >w  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); W NCdk$  
} xE:p)B-]  
for(int i=0;i<nEndPos.length-1;i++) :v+ 39  
{ zB4gnVhus|  
nEndPos = nStartPos[i+1]; juM?y'A  
} H~&'`h1  
nEndPos[nEndPos.length-1] = nFileLength; !^%b|=[  
} :DEZ$gi  
} mOBS[M5*  
zc_3\N  
1 OX(eXF>  
//启动子线程 @YRBZ6FH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Yd9y8Tq J  
for(int i=0;i<nStartPos.length;i++) I#0$5a},u^  
{ LY7'wONx  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (_D#gr{S=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), rTcH~s D`  
nStartPos,nEndPos,i); 4r %NtXAa  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <D?`*#K  
fileSplitterFetch.start(); uKplPze?  
} )Fbkt(1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !.!Ervi!N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q[ IaA"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4GJsVA(d|  
nEndPos = " + nFileLength); +'l@t bP  
// fileSplitterFetch[nPos.length-1].start(); #qzozQ4  
^K8Ey#T  
.- w*&Hd7b  
//等待子线程结束 p AD@oPC  
//int count = 0; hP #>`)aNY  
//是否结束while循环 dS-l2 $n  
boolean breakWhile = false; 2Tp.S3  
:`d& |BB  
+=*ZH `qX  
while(!bStop) 7yKadM~)  
{ (RQ kwu/  
write_nPos(); :Q 89j4,  
Utility.sleep(500); v6FYlKU@8  
breakWhile = true; H}d&>!\}F  
nI-\HAX  
Gk<h_1WWK  
for(int i=0;i<nStartPos.length;i++) >zhbOkR9c  
{ tH$Z_(5  
if(!fileSplitterFetch.bDownOver) 9G&l{7=  
{ <)&;9C  
breakWhile = false; <~]s+"oVc  
break; 3]T2Zp&;  
} m}k rG  
} Rh%x5RFFc  
if(breakWhile) *@dqAr%  
break; t>^An:xT  
C{4[7  
WVKzh  
//count++; Pr" 2d\  
//if(count>4) ,+0_kndR  
// siteStop(); dx|j,1e  
} {'JoVJKv  
0q81H./3  
A^G%8 )\  
System.err.println("文件下载结束!"); V^"5cW  
} /Ue~W, |  
catch(Exception e){e.printStackTrace ();} 2x0[@cT i?  
} V5m4dQ>t  
S?&ntUah  
uSH.c>  
//获得文件长度 (JOge~U  
public long getFileSize() B#8!8  
{ qWdL|8  
int nFileLength = -1; mI-$4st]  
try{ \ qKh9  
URL url = new URL(siteInfoBean.getSSiteURL()); @hp@*$#& 9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \G2&   
httpConnection.setRequestProperty("User-Agent","NetFox");  ,_HVPE  
.:E%cL +h  
cl[rgj  
int responseCode=httpConnection.getResponseCode(); yy@g=<okt\  
if(responseCode>=400) I;9>$?t[  
{ c<|;<8ew  
processErrorCode(responseCode); ftRf~5d2  
return -2; //-2 represent access is error dG\dGSZ\h  
} "4Cb dD//  
Y'wQ(6ok  
yi PMJ  
String sHeader; aVEg%8  
;BsyN[bF  
}Til $TT%H  
for(int i=1;;i++) ZJ1 %  
{ ry0P\wY}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); R]H/Jv\'  
//Utility.log(in.readLine()); }9=VhC%J  
sHeader=httpConnection.getHeaderFieldKey(i); Bg {"{poy  
if(sHeader!=null) *Mk5*_  
{ NvY%sx,  
if(sHeader.equals("Content-Length")) mGb,oj7l  
{ (V 5_q,2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @uApm~}  
break; 63 F@F t  
} Eu2@%2}P  
} ;.+sz(:hm  
else pKMy:j  
break; P`0}( '"U  
} @uXF(KDX  
} >La!O~d  
catch(IOException e){e.printStackTrace ();} 1?\G6T  
catch(Exception e){e.printStackTrace ();} qXcHf6  
J sde+G,N  
-pvF~P?8U  
Utility.log(nFileLength); :+06M@  
`ZhDoLpH<  
hX;JMQ915  
return nFileLength; e'Njl?>3  
} 5 o-WA1  
`saDeur#X  
D<% /:M  
//保存下载信息(文件指针位置) >NDI<9<'0}  
private void write_nPos() Gf*|f"O  
{ hj[&.w  
try{ u 6A!Sw  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Xy0*1$IS]  
output.writeInt(nStartPos.length); SHWD@WLE4  
for(int i=0;i<nStartPos.length;i++) g$+ $@~  
{ j6}/pe*;;T  
// output.writeLong(nPos); [TRHcz n  
output.writeLong(fileSplitterFetch.nStartPos); |L wn<y  
output.writeLong(fileSplitterFetch.nEndPos); ROb2g|YXG  
} kyR=U`OW  
output.close(); &V"9[0  
} P3Ocfpf Bp  
catch(IOException e){e.printStackTrace ();} ?QR13l(  
catch(Exception e){e.printStackTrace ();} VEFUj&t;xW  
} :Aq==N_/2  
f_'#wc6  
$^~dqmE2,  
//读取保存的下载信息(文件指针位置) _!_%Afz  
private void read_nPos() K FMx(fD  
{ w\SfzJN  
try{ x`9IQQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0q}k"(9  
int nCount = input.readInt(); GE?M. '!{{  
nStartPos = new long[nCount]; ^I!u H1G  
nEndPos = new long[nCount]; 1!/WC.0  
for(int i=0;i<nStartPos.length;i++) x:dI:G  
{ n3x< L:)  
nStartPos = input.readLong(); BeFCt;  
nEndPos = input.readLong(); -aSj-  
} n06T6oc  
input.close(); P~xP@? I%  
} uPh/u!  
catch(IOException e){e.printStackTrace ();} 3FetyW l'  
catch(Exception e){e.printStackTrace ();} pd%h5|*n;  
} 'fo.1  
):<9j"Z;At  
{zhajY7  
private void processErrorCode(int nErrorCode) r" 4u)H>  
{ +t[i68,%  
System.err.println("Error Code : " + nErrorCode); <gfkbDP2  
} Lfr>y_i;F  
i?^lEqy[  
?OD43y1rzd  
//停止文件下载 ^&8FwV]  
public void siteStop() <e)u8+(  
{ 7:Cq[u fl  
bStop = true; 7j,u&%om  
for(int i=0;i<nStartPos.length;i++) 7^bde<0  
fileSplitterFetch.splitterStop(); J)I|Xot  
(?y (0%q  
lE|Hp  
} 3]MSS\uB  
} ']Z1nb  
//负责部分文件的抓取 Cr&,*lUo  
**FileSplitterFetch.java =pa F6!AB  
*/ xryXO(  
package NetFox; y*oH"]D  
?hfyQhR  
QP?eK W9 :  
import java.io.*; ^ s.necg0  
import java.net.*; vXI2u;=y  
pXap<T  
M?[~_0_J  
public class FileSplitterFetch extends Thread { 4;;K1< 1  
P[q 'Y^\  
OK8|w]-A  
String sURL; //File URL =hAH6C  
long nStartPos; //File Snippet Start Position fY|P+{BO2  
long nEndPos; //File Snippet End Position ^E]Xq]vd"  
int nThreadID; //Thread's ID e<Bw duy  
boolean bDownOver = false; //Downing is over  X<p'&  
boolean bStop = false; //Stop identical x9Oo.[  
FileAccessI fileAccessI = null; //File Access interface -mfdngp3  
f?Am)  
XSBh+)0Ww  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {BI5lvx:  
{ F'Lav?^  
this.sURL = sURL; yb4Jsk5%  
this.nStartPos = nStart; LFwRTY,G  
this.nEndPos = nEnd; | > t,1T.  
nThreadID = id; ]:g;S,{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \A%s" O/  
} 'O:QS)  
W`k||U9  
9$Dsm@tX  
public void run() pVN) k  
{ (U?*Z/  
while(nStartPos < nEndPos && !bStop) wgPkSsuBuC  
{ '.$va<  
hO?RsYJ.F  
f%gdFtJ &  
try{ q'9}Hz  
URL url = new URL(sURL); ] -}Zd\Rs  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W|,Y*l  
httpConnection.setRequestProperty("User-Agent","NetFox"); I 7 B$X=  
String sProperty = "bytes="+nStartPos+"-"; ~E^lKe  
httpConnection.setRequestProperty("RANGE",sProperty); Gm1[PAj  
Utility.log(sProperty); P(|+1$#[  
C]01(UoSZ  
Pbo759q 1  
InputStream input = httpConnection.getInputStream(); m,|)$R  
//logResponseHead(httpConnection); 0x1#^dII  
j t6q8  
#]vs*Sz  
byte[] b = new byte[1024]; Ex`!C]sQ  
int nRead; ]>_Ie?L)<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) S9VD/  
{ lO+6|oF0  
nStartPos += fileAccessI.write(b,0,nRead); &l-1.muQ  
//if(nThreadID == 1) FG @ ')N!g  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,z@"pI b  
} 552yzn1  
i pi^sCYp  
_&U.DMt2 C  
Utility.log("Thread " + nThreadID + " is over!"); +3wVcL  
bDownOver = true; 6jaol'{SuH  
//nPos = fileAccessI.write (b,0,nRead); j~;kh_  
} bd & /B&a  
catch(Exception e){e.printStackTrace ();} Xe. az  
} xhTiOt6l  
} > 3SZD  
W? SFt z  
uKF)'gj  
//打印回应的头信息 | f}1bJE+  
public void logResponseHead(HttpURLConnection con) !kG2$/lR  
{ $kD ;*v=  
for(int i=1;;i++) ?ypX``3#s7  
{ 93]67PL#+  
String header=con.getHeaderFieldKey(i); ]hHL[hoFC  
if(header!=null) 9esMr0*=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); W! =X _  
Utility.log(header+" : "+con.getHeaderField(header)); xZc].l6  
else X8uAwHa6F  
break; xa&5o`>1G  
} PN"s ^]4  
} xC}9W6  
l.3|0lopX)  
IMT]!j&Y,  
public void splitterStop() |08'd5  
{ p~bx  
bStop = true; fFiFS\''V  
} ='z4bU  
0*{ 2^\  
]ur_G`B  
} o1^Rx5  
$AyE6j_1gX  
b>]MZhLJe  
/* X={Z5Xxr"  
**FileAccess.java w;=g$Bn  
*//文件访问(定位,写) *%p`Jk-U  
package NetFox; JQ"R%g` 8  
import java.io.*; g\~n5=-D  
8nKb mjM  
>\s8S}p  
public class FileAccessI implements Serializable{ U9/6F8D1Y1  
q:a-tdv2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d(!g9H  
RandomAccessFile oSavedFile; !QXPn}q^0  
long nPos; {I^@BW-  
,B8u?{O  
s+ a} _a:  
public FileAccessI() throws IOException 8{)j"rghah  
{ l1#F1q`^t  
this("",0); }T1.~E  
} FA7q pc  
U ,7O{YM  
3<A$lG  
public FileAccessI(String sName,long nPos) throws IOException qC4Q+"'  
{ `-)Hot)  
oSavedFile = new RandomAccessFile(sName,"rw"); 1n-+IR"  
this.nPos = nPos; FofeQ  
oSavedFile.seek(nPos); A(v5VvgZE  
} {1Hs5bg@  
Q xm:5P  
)0UXTyw^  
public synchronized int write(byte[] b,int nStart,int nLen) ~M Mv+d88  
{ Wfp>BC  
int n = -1; hcX`X2^  
try{ )8@|+'q  
oSavedFile.write(b,nStart,nLen); O+ghw1/  
n = nLen; <4%cKW0  
} ;,7/>Vt  
catch(IOException e) al@Hr*'  
{ 2Sb68hJIE  
e.printStackTrace (); cD JeYduK  
} `c.P`@KA  
;t\oM7J|  
Je &O  
return n; #C#*yE  
} h*B7UzCg  
{"WfA  
hRaX!QcG3  
} D\0q lCAs  
zbgH}6b  
({!S!k  
/* 1G`zwfmh~  
**SiteInfoBean.java }[mLtv%&  
*/ b2Oj 1dP1  
package NetFox; Zp qb0ro  
S17 c#6vT  
z;Yo76P  
public class SiteInfoBean { L{F[>^1Sb  
pz0Q@n/X  
peD7X:K\s  
private String sSiteURL; //Site's URL ^SvGSx i  
private String sFilePath; //Saved File's Path }O+`X) 9  
private String sFileName; //Saved File's Name oa<%R8T?@  
private int nSplitter; //Count of Splited Downloading File M"!{Dx~  
F|bg2)|du8  
.g?Ppma  
public SiteInfoBean() ~v|NC([(  
{//nSplitter的缺省值为5 -I'Jm=q3]  
//default value of nSplitter is 5 )l6(ss!J  
this("","","",5); W'! I+nh  
} 35 d:r:  
ArVW2gL  
uWDWf5@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4`zK`bRcK#  
{ PFI^+';  
sSiteURL= sURL; &1Cif$Y4w  
sFilePath = sPath;  sDl @  
sFileName = sName; 7?"-:q  
this.nSplitter = nSpiltter; zJH:`~GxE  
tb/`*Yl@  
9(pF!}1 %\  
} }P\J?8  
k, >*.Yoh  
(MzThGJK_  
public String getSSiteURL() 7!PU}[:  
{ +. tcEbFL  
return sSiteURL; oZ\zi> Y,  
} ]Wg&r Y0  
z*e`2n#\  
,{Ga7rH*   
public void setSSiteURL(String value) vWVQ8S.  
{ +HkEbR'G0  
sSiteURL = value; w[]\%`69}Z  
} 7RCVqc"  
4WXr~?Vq9  
TR'<D9kn  
public String getSFilePath() 5gKXe4}\/|  
{ =z*SzG  
return sFilePath;  N~vK8j@  
} OICH:(t_  
MmH(dp+  
Y$0K}`{  
public void setSFilePath(String value) [oG Sy5bB  
{ "?S> }G\  
sFilePath = value; Rc(E';uc  
} R/P9=yvg0  
auHP^O> 4L  
0w!:YB,}  
public String getSFileName() *0/%R{+S  
{ YJB/*SV^  
return sFileName; ge|Cv v  
} rYO~/N  
'k9 Qd:a}  
Z)!#+m83>-  
public void setSFileName(String value) %TYe]^/'y  
{ m2v'zJd}g  
sFileName = value; 2Q)pT$  
} ]zh6[0V7V  
Yv"-_  
/E^j}H{  
public int getNSplitter() f{+X0Oj  
{ tvOyT6]  
return nSplitter; o+g\\5s  
} iJb-F*_y  
>2ny/AK|  
O2S{*D={  
public void setNSplitter(int nCount) (".WJXB\  
{ 8V@\$4@b!#  
nSplitter = nCount; C] M{  
} [[ uZCKi  
} UUEbtZH;  
j"9Zaq_  
1O+$"5H  
/* l 9bg  
**Utility.java PBb'`PV  
*/ \OVw  
package NetFox; :~\ y<  
p!7(a yu  
S4D~`"4 $/  
public class Utility { 8X)1bNGqhe  
,lQfsntk'  
cB_ 3~=fV  
public Utility() 9 =D13s(C  
{ 9d8U@=  
fKNDl\SD  
N >k,"=N /  
} MrhJk  
Hh'o:j(^  
//线程睡眠 vPM 2cc/o  
public static void sleep(int nSecond) -5Aqf\  
{ +t}<e(  
try{ @] 3`S  
Thread.sleep(nSecond); LX7<+`aa  
} [='<K  
catch(Exception e) F32U;fp3  
{ 0pA>w8mh  
e.printStackTrace (); B+lnxr0t  
} aj}#~v1  
} hD,@>ky  
VL2ACv(  
//日志 UQ~gjnb[c  
public static void log(String sMsg) 3$P GLM  
{ pXf5/u8&  
System.err.println(sMsg); |3=tF"h  
} :s#&nY  
YQaL)t$0  
%kL]-Z  
public static void log(int sMsg) 9` G}GU]@}  
{ !uN_<!  
System.err.println(sMsg); FmhN*ZXr #  
} z6'l" D'h  
} :PP!v!vk  
DHh30b$c  
;k8U5=6a  
/* fX}dQN~z  
**TestMethod.java !==C@cH<N  
*/ 5mg] su&#  
package NetFox; c{!XDiT]P  
vf?m-wh  
XT\Q"=FD  
public class TestMethod { \"l/D?+Q  
L lVE5f?  
/igbn  
public TestMethod() A#CGD0T  
{ ///xx/weblogic60b2_win.exe xcC^9BAj  
try{ 7jYW3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :+UahwiRD"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); dgW/5g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); kx07Ium  
fileFetch.start(); #RP7?yGM,  
} Df0m  
catch(Exception e){e.printStackTrace ();} yYvv!w+@Q  
PZhpp"  
bf$4Z: Y  
} fe7DS)U  
zwdi$rM5  
Q9sxI}D )R  
public static void main(String[] args) \O+Hmi^  
{ ux1SQ8C*  
new TestMethod(); OB\jq!"  
} JV;-P=o1B  
} HKYJgx  
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