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http断点续传简单实现(java)

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/* }2;{ }J  
**SiteFileFetch.java ja Ot"iU.B  
*/ FE[{*8  
package NetFox; l*0`{R  
import java.io.*; YYiT,Xp<A  
import java.net.*; P:3%#d~q  
|AS`MsbI9  
w*3DIVlxL  
public class SiteFileFetch extends Thread { 1qgzb  
(8?5REz  
w]Fi:kV  
SiteInfoBean siteInfoBean = null; //文件信息Bean (qQ|s@O  
long[] nStartPos; //开始位置 |vLlEN/S  
long[] nEndPos; //结束位置 5( }Qg9%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 A!\-e*+W=  
long nFileLength; //文件长度 GSh~j-C'  
boolean bFirst = true; //是否第一次取文件 4-dV%DgC  
boolean bStop = false; //停止标志 {k#RWDespy  
File tmpFile; //文件下载的临时信息 4\?GA`@  
DataOutputStream output; //输出到文件的输出流 C $r]]MSj  
G'\x9%  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ?t{ 2y1  
public SiteFileFetch(SiteInfoBean bean) throws IOException TzW1+DxM5  
{ $[NC$*N7  
siteInfoBean = bean; :+nECk   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z/IZ ;K_e  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "VfV;)]|w  
if(tmpFile.exists ()) mEM/}]2  
{ V(LE4P 1  
bFirst = false; /cN. -lEo%  
read_nPos(); k.d Q;v}  
} Ue8k9%qV  
else A` iZ"?  
{ Ub%sw&QG(9  
nStartPos = new long[bean.getNSplitter()]; KW[Jft  
nEndPos = new long[bean.getNSplitter()]; 3IK+&hk  
} VSJ08Ngi   
5{@Hpj/B  
xr<.r4  
 K#LG7faj  
} RlH~<|XK  
mI[$c"!BD  
Oy `2ccQ#  
public void run() D]h~ \  
{ L9FijF7  
//获得文件长度 E{-W#}#  
//分割文件 vMQvq9T}  
//实例FileSplitterFetch Q5N;MpJ-  
//启动FileSplitterFetch线程 1 =cFV'  
//等待子线程返回 mAFVjSa2  
try{ npW1Z3n  
if(bFirst) vG7aT  
{ ^z^ UFW  
nFileLength = getFileSize(); :<}.3Q?&  
if(nFileLength == -1) -}W `  
{ WRWcB  
System.err.println("File Length is not known!"); G\S>H  
} NSPa3NE  
else if(nFileLength == -2) q[}[w!to  
{ b)eKa40Z  
System.err.println("File is not access!"); A`D^}F6  
} rLfhm Ds%u  
else eZr}xo@9  
{ l*yh(3~}  
for(int i=0;i<nStartPos.length;i++) A>c/q&WUk  
{ V=C@ocy Z  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  EK:s#  
} @YMQbjbr  
for(int i=0;i<nEndPos.length-1;i++) JmR) g  
{ t[.wx.y&0  
nEndPos = nStartPos[i+1]; G}lP'9/  
} Ofyz,% |Q  
nEndPos[nEndPos.length-1] = nFileLength; %Ny`d49&  
} #xopJaY  
} ?B&@  
l9 |x7GB  
XgfaTX*  
//启动子线程 O;ty k_yM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; FZEK-]h.  
for(int i=0;i<nStartPos.length;i++) Zy -&g:  
{ ZL-YoMHc+_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '|\et aD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), R`RLq1WA  
nStartPos,nEndPos,i); {c3u!} mW  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YJ&K0 %R  
fileSplitterFetch.start(); bYKyR}e  
} W:8*Z8?7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {\?zqIM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #()u=)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g]z[!&%Ahs  
nEndPos = " + nFileLength); iZVMDJ?(Z]  
// fileSplitterFetch[nPos.length-1].start(); U~mv1V^.  
mh#dnxeR  
KXgC]IO~  
//等待子线程结束 &tULSp@J  
//int count = 0; }Ot I8;>  
//是否结束while循环 G$5N8k[2  
boolean breakWhile = false; O>E2G]K]\  
$hkMJ),T~  
~)zoIM\  
while(!bStop) A-GRuC  
{ -,;Iob56!  
write_nPos(); 9\/T #EP  
Utility.sleep(500); Qr/8kWa0 C  
breakWhile = true; EzDj,!!<w  
6T}bD[h4?  
nC3U%*l  
for(int i=0;i<nStartPos.length;i++) XcS 8{  
{ pX:FXzYQ  
if(!fileSplitterFetch.bDownOver) p<|I!n&9  
{ 93Yo }6>  
breakWhile = false; 0`KB|=>  
break; 1GnT^u y/  
} <(]e/}  
} s_=/p5\  
if(breakWhile) Dj<]eG]  
break; uhuwQS=X  
VWlOMqL995  
Fr}e-a  
//count++; 959i2z  
//if(count>4) K)Nbl^6x  
// siteStop(); qzVmsxBNP  
} 8?GS:+  
P&/PCSf  
^N!l$&=  
System.err.println("文件下载结束!"); }LH>0v_<Y  
} web =AQ5I4  
catch(Exception e){e.printStackTrace ();} jb' hqz  
} p%A(5DE  
62B` Z5j#  
Phsdn`,  
//获得文件长度 5q`d=L,  
public long getFileSize() Ojkbv  
{ ^|6%~jkD5  
int nFileLength = -1; W^2Q"c#7F  
try{ {d\erG(  
URL url = new URL(siteInfoBean.getSSiteURL()); ()}B]?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1n! Jfs U  
httpConnection.setRequestProperty("User-Agent","NetFox"); APT'2 -I_  
T/ CI?sn  
s D] W/  
int responseCode=httpConnection.getResponseCode(); rsP3?.E  
if(responseCode>=400) uf* sI  
{  0gBD  
processErrorCode(responseCode); _Cv({m&N  
return -2; //-2 represent access is error %C= {\]-2~  
} wSp1ChS k  
"`DCXn#mB  
krTH<- P  
String sHeader; bA-=au?o5  
'#SacJ\L7  
Q{Gi**<  
for(int i=1;;i++) #,O<E@E  
{ ;T}#-`O_Im  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }Po&6^  
//Utility.log(in.readLine()); Yn,dM~|Cc  
sHeader=httpConnection.getHeaderFieldKey(i); R/ 7G  
if(sHeader!=null) k/vE|  
{ ?op6_a-wm  
if(sHeader.equals("Content-Length")) hq.z:D  
{ cLH|;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Bv $;yR  
break; tw8@&8"  
} yV :DR  
} #F5O>9hA  
else f/ 9]o  
break; rUkiwqr~E  
} J<:qzwh  
} 6uQfe? aD  
catch(IOException e){e.printStackTrace ();} ZD1UMB0$4  
catch(Exception e){e.printStackTrace ();} y&\ J  
"sz)~Q'W5  
5gg_c?Vh/  
Utility.log(nFileLength); '$~9~90?Z  
__""!Yz  
65RWaz;|  
return nFileLength;  OvU]|4h  
} Tn[DF9;?  
-p`hevRr  
-san%H'  
//保存下载信息(文件指针位置) ,,oiL  
private void write_nPos() ]%(hZZ  
{ )'M<q,@<(  
try{ s4lkhoN\t  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ):eX*  
output.writeInt(nStartPos.length); KYVB=14  
for(int i=0;i<nStartPos.length;i++) )cB00*/  
{ I ms?^`N  
// output.writeLong(nPos); _ Onsfv  
output.writeLong(fileSplitterFetch.nStartPos); -MoI{3a  
output.writeLong(fileSplitterFetch.nEndPos); ,;C92XY  
} $lci{D32,  
output.close(); *G$tfb(  
} JP9eNc[  
catch(IOException e){e.printStackTrace ();} 'OSZ'F3PV  
catch(Exception e){e.printStackTrace ();} nJ.p PzH2g  
} !1!;}uzt  
di`Ql._M  
t/HMJ  
//读取保存的下载信息(文件指针位置) {hK$6bD3^  
private void read_nPos() V{;Mh u`+  
{ GDP@M)~6*  
try{ \?h +  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |h(!CFR  
int nCount = input.readInt(); =)"60R7{  
nStartPos = new long[nCount]; .Nr}V.?57  
nEndPos = new long[nCount]; rE[*i q,#  
for(int i=0;i<nStartPos.length;i++) p+#J;.  
{ Bm"jf]  
nStartPos = input.readLong(); +"Ek? )?  
nEndPos = input.readLong(); }Gr5TDiV0\  
} !)ey~Suh  
input.close(); N%/Qc hu  
} B+eB=KL  
catch(IOException e){e.printStackTrace ();} g=Q#2/UQ<  
catch(Exception e){e.printStackTrace ();} x$I~y D  
} /K<Xr[z~y  
^10*s,(uS?  
pq+Gsu1^  
private void processErrorCode(int nErrorCode) md_aD  
{ VR2BdfKU,  
System.err.println("Error Code : " + nErrorCode); ,\4@Ao  
} \TkBV?W  
pNr3u  
z m\=4^X  
//停止文件下载 w<&Nn`V  
public void siteStop() ]K?z|&N|HK  
{ 4vPQuk!  
bStop = true; a*6x^R;)  
for(int i=0;i<nStartPos.length;i++) +Vt@~Z4K  
fileSplitterFetch.splitterStop(); O*rKV2\  
rPkV=9ull,  
bV|:MW <Wv  
} <_8\}!  
} ' ~lC85  
//负责部分文件的抓取 ;2@MPx  
**FileSplitterFetch.java {-J/ <a@  
*/ Wk$[;>NU3  
package NetFox; '81$8xxdY  
,sP7/S)FR  
qbu Lcy3  
import java.io.*; #*j  
import java.net.*; cG6Q$  
h" Yi'  
DY^q_+[V  
public class FileSplitterFetch extends Thread { yp wVzCUG  
Duj9PV`2  
8fTuae$^  
String sURL; //File URL Yq4_ss'nB  
long nStartPos; //File Snippet Start Position kM*f9x  
long nEndPos; //File Snippet End Position ,'m<um  
int nThreadID; //Thread's ID oOBN  
boolean bDownOver = false; //Downing is over lLxKC7b  
boolean bStop = false; //Stop identical cgc| G  
FileAccessI fileAccessI = null; //File Access interface .1 .n{4z>:  
0vQ@n7  
fOm=#:O  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &9, 6<bToP  
{ Nj*J~&6G  
this.sURL = sURL; (ScL  C  
this.nStartPos = nStart; Xgn^)+V:  
this.nEndPos = nEnd; 5@P2Z]Q  
nThreadID = id; \;I%>yOIu  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $dFEC}1t  
} ?%i|].<-'  
Cd#[b)d ?^  
FGG Fi(  
public void run() PbJn8o   
{ *J=`"^BO  
while(nStartPos < nEndPos && !bStop) bk}.^m!  
{ ,;y 5Mu8  
])'22sY  
2Prr:k  
try{ D@!`b6  
URL url = new URL(sURL); 0diQfu)Fi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;XSV}eLu  
httpConnection.setRequestProperty("User-Agent","NetFox"); }ARWR.7Cc  
String sProperty = "bytes="+nStartPos+"-"; H5S>|"`e`e  
httpConnection.setRequestProperty("RANGE",sProperty); Q*ZqY  
Utility.log(sProperty); Z9cch- u~  
@ T'!;)  
Dh BUMDoB  
InputStream input = httpConnection.getInputStream(); .8uJ%'$)  
//logResponseHead(httpConnection); qS*qHT(u19  
9(QY~F  
\'&:6\-fw  
byte[] b = new byte[1024]; R#`hT  
int nRead; q%bNT  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L:IaJ?+?  
{ fJn;|'H!  
nStartPos += fileAccessI.write(b,0,nRead); l6:k|hrm;  
//if(nThreadID == 1) D!Owm&We  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ry,_ %j3  
} aU<0<Dx  
.<gA a"  
xv]P-q0  
Utility.log("Thread " + nThreadID + " is over!"); $T8Ni!#/C  
bDownOver = true; <oS2a/Nd  
//nPos = fileAccessI.write (b,0,nRead); /PE3>"|wE  
} o_t2 Z  
catch(Exception e){e.printStackTrace ();} \kF}E3~+#  
} eA$9)K1GO  
} J~V`"uo  
<@.f#  
-d[9mS  
//打印回应的头信息 /~{8/u3  
public void logResponseHead(HttpURLConnection con) T12?'JL^r  
{ >7!4o9)c  
for(int i=1;;i++) ?9mFI(r~  
{ w[I%Id;E  
String header=con.getHeaderFieldKey(i); X<Rh-1$8F  
if(header!=null) ,v4Z[ (  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); B#&U5fSw+0  
Utility.log(header+" : "+con.getHeaderField(header)); 8b8ui  
else eG72=l)Mz  
break; cR 4xy26s  
} "pa5+N&2-  
} S7P](F=n#  
NS6#od ZeV  
GC?\GV  
public void splitterStop() {# ;e{v  
{  e-sMU  
bStop = true; _ M8Q%  
} !`hiXDk*2  
@`G_6 <.`  
-PbGNF  
} afqLTWU S  
1 y$Bz?4  
=SA@3)kHH  
/* IVzJ|  
**FileAccess.java ;Z-xum{  
*//文件访问(定位,写) 3v :PBmE  
package NetFox; B'"C?d<7  
import java.io.*; S) Sv4Qm  
V.Dqbv  
^&am]W;T  
public class FileAccessI implements Serializable{ %L.,:mtq)  
$xNM^O  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  0$b)@  
RandomAccessFile oSavedFile; o/@.*Rj>Bg  
long nPos; eL JW  
k {_X%H/  
MLtfi{;LH  
public FileAccessI() throws IOException wQgW9546  
{ N&K:Jp  
this("",0); G4{ zt3{  
} 9eo$Duws  
*>h"}e41  
U2\g Kg[-Q  
public FileAccessI(String sName,long nPos) throws IOException c}kZ x1  
{ T~J6(,"  
oSavedFile = new RandomAccessFile(sName,"rw"); ZE.nB- H  
this.nPos = nPos; m{9m.~d  
oSavedFile.seek(nPos); NVU@m+m~  
} } 1^/[?  
e7T"?s  
`*mctjSN  
public synchronized int write(byte[] b,int nStart,int nLen) `of 5h* k  
{ j2\bCGY  
int n = -1; <k-&Lh:o3  
try{ =o^oMn  
oSavedFile.write(b,nStart,nLen); RMUR@o5N  
n = nLen; i 2hP4<;h  
} J3KY?,g3O_  
catch(IOException e) mRZC98$ @r  
{  ;)s$Et%  
e.printStackTrace (); wkOo8@J\  
} 6+u}'mSj8  
Eo 5p-  
f=]+\0MQ  
return n; Pc#8~t}2  
} U+>!DtOYK  
X<dQq`kZ  
.I$ Q3%s  
} )XV|D  
,X25-OFZ  
,V'+16xW  
/* izy7. (.a  
**SiteInfoBean.java Tqz{{]%j~$  
*/ :# s 6,  
package NetFox; bO]^TRaiJ  
!#j y=A  
43-mv1>.  
public class SiteInfoBean { PeGA+0bm  
92!1I$zi  
T4dLuJl  
private String sSiteURL; //Site's URL /yPFts_q  
private String sFilePath; //Saved File's Path 1wP#?p)c  
private String sFileName; //Saved File's Name JwG$lGNJ  
private int nSplitter; //Count of Splited Downloading File 0$NcxbM  
LsH&`G^<  
'Vq <;.A  
public SiteInfoBean() 8dgI&t  
{//nSplitter的缺省值为5 mz$)80ly  
//default value of nSplitter is 5 d2`m0U  
this("","","",5); (8qD'(@  
} > 2_xRn<P  
1Z%^U ?  
^0vK >  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 11t+ a,fM  
{ BwMi@r =  
sSiteURL= sURL; n6 D9f~8"  
sFilePath = sPath; 95LZG1]Rb  
sFileName = sName; 3Kuu9< 0  
this.nSplitter = nSpiltter; qn) VKx=  
~R^~?Y%+<  
h&@ A'om~  
} QY2/mtI  
h6J0b_3h4  
lZ]x #v  
public String getSSiteURL() ~Sy/q]4ys*  
{ C".nB12  
return sSiteURL; 7i^7sT8t  
} +g/TDwyVH  
s jl(  
4)MKYhm  
public void setSSiteURL(String value) ,dn6z#pb+  
{ V&nTf100  
sSiteURL = value; 1./ uJB/  
} /g$cQ=c  
d&[Ct0!++u  
Y'K+O  
public String getSFilePath() JxI\ss?O  
{ @CGci lS=  
return sFilePath; `;KU^dH  
} ueI1O/Mi  
D<=x<.  
o[Ojl .r<  
public void setSFilePath(String value) ;k1 \-  
{ eh4`a<gC  
sFilePath = value; 7G6XK   
} MR4e.+#E  
}/)vOUcEd  
2stBW5v3  
public String getSFileName() ((KNOa5  
{ <zd_-Ysn  
return sFileName; U~9Y9qzy,  
} P`z#tDT^"  
v9?hcJ=  
R"@J*\;$T  
public void setSFileName(String value) H}v.0R  
{ '+?L/|'  
sFileName = value; 6<aZr\Ufg  
} aqL#g18  
3JhT  
f@JMDJ  
public int getNSplitter() UqVcN$^b  
{ GM]" $  
return nSplitter; %Xe#'qNq)  
} 73/DOF  
$H\[yg>4  
PSCzeR  
public void setNSplitter(int nCount) 6(#fGH&[  
{ RP!!6A6:  
nSplitter = nCount; jhRg47A  
} K<k!sh   
} U&F1}P$fb  
!4;A"B(  
#kGgz O  
/* "gt-bo.,  
**Utility.java ,<Ag&*YE4  
*/ 5hxG\f#}?  
package NetFox; l]g /rs  
x}^ :Bs+j  
@*Y"[\"$  
public class Utility { mGZJ$|  
$] ])FM"b  
c> SFt tbU  
public Utility() u92);1R  
{ ,\){-H/n  
\,n|V3#G  
#|92 +  
} 2OA0rH"v  
cj[a^ ZH  
//线程睡眠 3VI[*b  
public static void sleep(int nSecond) 9\dpJ\  
{ m8jQ~OS  
try{ j\I{pW-  
Thread.sleep(nSecond); ,(&p "O":  
}  dmR>u  
catch(Exception e) |\}&mBR  
{ @Sr{6g*I  
e.printStackTrace (); (7X|W<xT  
} [TW?sW^0  
} z`Jcpt  
lRk)  
//日志 :CeK 'A\  
public static void log(String sMsg) &gxWdG}qx]  
{ JJQS7,vG  
System.err.println(sMsg); QLPb5{>KDS  
}  iH`Q4  
*dAQ{E(rO  
*XU2%"Sc  
public static void log(int sMsg) N1',`L5  
{ ~cf*Oq  
System.err.println(sMsg); ^cz4nW<  
} A,'F`au  
} 2@Nt6r  
3 P=I)q  
H1t`fyri2  
/* xS'Kr.S  
**TestMethod.java h&| S*  
*/ IgmCZ?l&0  
package NetFox; |&oTxx$S  
M1mx{<]A  
{py"Ob_  
public class TestMethod { {`ghX%M(l  
1u~CNHm  
X7~^D[ X  
public TestMethod() i8h^~d2"  
{ ///xx/weblogic60b2_win.exe R/WbcQ)  
try{ q\$k'(k>35  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6"L,#aKm^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); : MEB] }  
SiteFileFetch fileFetch = new SiteFileFetch(bean); QM) ob  
fileFetch.start();  5(\H:g\z  
} |Wg!> g!  
catch(Exception e){e.printStackTrace ();} E]P7u"1  
yg^ 4<A  
+^cjdH*  
} j[RY  
z 0}JiWR  
D#k ~lEPub  
public static void main(String[] args) u~~H'*EM  
{ =j"bLX6;  
new TestMethod(); _2a)b(<tF  
} t?(fDWd|-  
} W; zzc1v  
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