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http断点续传简单实现(java)

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/* !]7L9TGn  
**SiteFileFetch.java wz:,gpH  
*/ 11fV|b%  
package NetFox; 6(A"5B=\  
import java.io.*; +'[*ikxD=g  
import java.net.*; XK0lv8(  
daQJ{Cd,w  
X1u\si%.4S  
public class SiteFileFetch extends Thread { 1':};}dCJ  
KlwB oC/{K  
6TQ[2%X'  
SiteInfoBean siteInfoBean = null; //文件信息Bean v&66F`  
long[] nStartPos; //开始位置 kk CoOTe&  
long[] nEndPos; //结束位置 d.U"lP/)D  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +- hfl/$  
long nFileLength; //文件长度 x+Ly,9nc$  
boolean bFirst = true; //是否第一次取文件 _(@V f=t  
boolean bStop = false; //停止标志 >8`;SEnv  
File tmpFile; //文件下载的临时信息 [|YuT:Cp  
DataOutputStream output; //输出到文件的输出流 E.x<J.[Y  
ICWHEot  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Ob|tA  
public SiteFileFetch(SiteInfoBean bean) throws IOException VW] ,R1q  
{ &D7Mv5i0@  
siteInfoBean = bean; /5f=a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9J}^{AA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); G$lE0_j2{  
if(tmpFile.exists ()) +5Y;JL<%/  
{ /EVXkf0  
bFirst = false; w (odgD  
read_nPos(); clT[ ?8*  
} j'SGZnsy*  
else # *7ImEN  
{ cw~-%%/  
nStartPos = new long[bean.getNSplitter()]; \Dx)P[Ur  
nEndPos = new long[bean.getNSplitter()]; :-+j,G9 t  
} T'14OU2N{Y  
]rO/IuB  
P`n"E8"ab<  
'81WogH:  
} X/S%0AwZ  
`6*1mE1K&  
g`H;~ w  
public void run() U;U19[]  
{ H<3a yp$  
//获得文件长度 7}Jn`^!  
//分割文件 ENZYrWl  
//实例FileSplitterFetch 69``j{Z+  
//启动FileSplitterFetch线程 Qy'-3GB  
//等待子线程返回 8H{9  
try{ KyzdJ^xC"  
if(bFirst) t,yMO  
{ Q~)A fa{  
nFileLength = getFileSize(); 212  
if(nFileLength == -1) 6p~8(-nG  
{ Y:5Gp8Vi  
System.err.println("File Length is not known!"); U0dhr;l  
} e>_Il']Mb  
else if(nFileLength == -2) {&)E$ M  
{ .:TSdusr~  
System.err.println("File is not access!"); ;-{'d8  
} D~f[Rg  
else W&9X <c*  
{ O['5/:-  
for(int i=0;i<nStartPos.length;i++) M}!E :bv'  
{ d>`s+B9K0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @t,Y< )U  
} YR0.m%U,  
for(int i=0;i<nEndPos.length-1;i++) ]iH~ 1[  
{ Ku]<$uo  
nEndPos = nStartPos[i+1]; JO|xX<#:  
} 2@$`xPg  
nEndPos[nEndPos.length-1] = nFileLength; b:6e2|xf?  
} ,V # r  
} 9rM6kLD  
6vebGf  
n~v*  
//启动子线程 #w]@yL]|is  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [|oOP$u  
for(int i=0;i<nStartPos.length;i++) JReJlDu  
{ [X'u={  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `:;fc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LE4P$%>H  
nStartPos,nEndPos,i); ynG@/S6)K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aX(Y `g)|  
fileSplitterFetch.start(); !1Z rS  
} tJZ3P@ L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {t QZqqdn@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >iFi~)i_4y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", DeR C_ [  
nEndPos = " + nFileLength); CC{{@  
// fileSplitterFetch[nPos.length-1].start(); J nf@u  
kU[#. y=%p  
P)&qy .+E0  
//等待子线程结束 SOo}}a0  
//int count = 0; C(lGW,!  
//是否结束while循环 s N|7   
boolean breakWhile = false; z Feo8S  
"gGv>]3  
&{H LYxh   
while(!bStop) h(3ko An  
{ 8d*W7>rq  
write_nPos(); ,lr\XhO  
Utility.sleep(500); .3< sv  
breakWhile = true; !O*uQB  
g~Agy  
$z*Y:vFP  
for(int i=0;i<nStartPos.length;i++) w2e 9Ue~WH  
{ Vo:Gp  
if(!fileSplitterFetch.bDownOver) =hDFpb,mr  
{ ZT%Q:]B+  
breakWhile = false; f%5 s8)  
break; ? _Y2'O  
}  Vq K/GWg  
} yUp"%_t0  
if(breakWhile) S 0L"5B@  
break; 2C_/T8  
*Z C$DW!-  
Hlye:.$  
//count++; KJ;NcUq  
//if(count>4) bO\E)%zp  
// siteStop(); a>XlkkX  
} $3Srr*  
qJf=f3  
bf1EMai"  
System.err.println("文件下载结束!"); "fX9bh^  
} m03]SF(#3  
catch(Exception e){e.printStackTrace ();} 7z^\}&  
} t~@~XI5  
w*7BiZ{s<  
x;p7n 2_  
//获得文件长度 -P7JaH/Q  
public long getFileSize() 25CO_  
{ F9 q9BH  
int nFileLength = -1; F1UTj "<e  
try{ RbGq$vYol/  
URL url = new URL(siteInfoBean.getSSiteURL()); &['cZ/bM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @Ap~Wok  
httpConnection.setRequestProperty("User-Agent","NetFox"); [  bB   
Dhy@!EOS  
vgvJ6$#  
int responseCode=httpConnection.getResponseCode(); K\a=bA}DG  
if(responseCode>=400) 8KhE`C9z  
{ `oUuAL  
processErrorCode(responseCode); mhZ60RW  
return -2; //-2 represent access is error {Mx3G*hr  
} "<5su5]  
60r4%> d  
=& .KKr  
String sHeader; [$[1|r *Q  
^ H )nQ  
p!]$!qHO (  
for(int i=1;;i++) u#uT|a.  
{ F1aI4H<(T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); s GdlS&08(  
//Utility.log(in.readLine()); Az"(I>VfD  
sHeader=httpConnection.getHeaderFieldKey(i); }"CX`  
if(sHeader!=null) S LSbEm  
{ }HC6m{vH(  
if(sHeader.equals("Content-Length")) 6 (@U+`  
{ 6~_ TXy/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); FG[YH5  
break; bQFMg41*w7  
} I"1H]@"=  
} mcB8xE  
else /9..hEq^  
break; NiCB.a  
} drc]"6 k  
} 7-u['nFJ  
catch(IOException e){e.printStackTrace ();} q!+&|F  
catch(Exception e){e.printStackTrace ();} L 2k?Pl  
<5wk~|@t  
<B %s9Zy  
Utility.log(nFileLength); V<%eWT)x7C  
9;*-y$@  
&>]c"?C*  
return nFileLength; ;5(ptXX1W  
} 8vL2<VT;  
/PuN+M  
Sl RQi:  
//保存下载信息(文件指针位置) !QTfQ69Y0  
private void write_nPos() ;@R=CQ6  
{ 2GRdfX  
try{ qB0F9[U  
output = new DataOutputStream(new FileOutputStream(tmpFile)); B<p -.tv  
output.writeInt(nStartPos.length); WzwH;!  
for(int i=0;i<nStartPos.length;i++) 2a 3RRP  
{ WFTXSHcG  
// output.writeLong(nPos); yaD_c;  
output.writeLong(fileSplitterFetch.nStartPos); X/l{E4Ex  
output.writeLong(fileSplitterFetch.nEndPos); 3r]:k) J  
} XzBnj7E  
output.close(); ,4&?`Q  
} `f~\d.*U  
catch(IOException e){e.printStackTrace ();} {hmC=j  
catch(Exception e){e.printStackTrace ();} wG\ +C'&~  
} --}5%6  
" A}S92  
6yN8 (&`  
//读取保存的下载信息(文件指针位置) #2~-I  
private void read_nPos() `,O#r0m  
{ +%%Ef]  
try{ }+{ ? Ms  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); } qf=5v  
int nCount = input.readInt(); f=L&>X  
nStartPos = new long[nCount]; Q*J8`J:#^R  
nEndPos = new long[nCount]; ~5Cid)Q}@o  
for(int i=0;i<nStartPos.length;i++) :p@.aD5  
{ &Oih#I  
nStartPos = input.readLong(); VoTnm   
nEndPos = input.readLong(); */7+pk(  
} >Yf)]e-  
input.close(); G'M;]R9EP  
} K#e&yY  
catch(IOException e){e.printStackTrace ();} k+D"LA%J  
catch(Exception e){e.printStackTrace ();} ?b8 :  
} KT>eE  
oN\IQ7oI  
BsJ d*-:X  
private void processErrorCode(int nErrorCode) ,3As Ng  
{ ]#fmih^  
System.err.println("Error Code : " + nErrorCode); m/T3Um  
} #BZ2%\  
?E*;fDEC  
oieJ7\h]m  
//停止文件下载 3;hztCZj  
public void siteStop() hN5?u:  
{ m 3 Y@p$i5  
bStop = true; ~mR@L`"l  
for(int i=0;i<nStartPos.length;i++) t6+c"=P#  
fileSplitterFetch.splitterStop(); ]"2;x  
C2[* $ 1U  
XDtMFig  
} 1[g -f ,  
} @  gv^  
//负责部分文件的抓取 u3B[1Ae:K  
**FileSplitterFetch.java YXi'^GU@  
*/ UBm L:Qv  
package NetFox; +'ZJ]  
>OLKaghV.5  
XjRk1 ~  
import java.io.*; Biva{'[m  
import java.net.*; RI[=N:C^  
#aeKK7[  
s.#%hPX{  
public class FileSplitterFetch extends Thread { |}-bMQ|  
_-M27^\vV  
S#^2k!(|G  
String sURL; //File URL 0'3f^Ajf  
long nStartPos; //File Snippet Start Position &&daQg4Ha  
long nEndPos; //File Snippet End Position nhu;e}[>  
int nThreadID; //Thread's ID c&mLK1A6  
boolean bDownOver = false; //Downing is over L/Ytkag  
boolean bStop = false; //Stop identical WCdl 25L#  
FileAccessI fileAccessI = null; //File Access interface w!j'k|b>  
sMn)[k vX  
AVnH|31dC~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C+m%_6<  
{ zFba("E Z  
this.sURL = sURL; $5]}]  
this.nStartPos = nStart; 2I|`j^  
this.nEndPos = nEnd; c;13V(Djy  
nThreadID = id; ]VkM)< +  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 dKk#j@[n"  
} (^@rr[. o7  
d:X@zUR*)  
X"k:+  
public void run() u{'|/g&  
{ Km)VOX[ZZ  
while(nStartPos < nEndPos && !bStop)   L* 0$x  
{ a7fFp 9l!  
@,:6wKMc  
44x+2@&1  
try{ lM |}K-2  
URL url = new URL(sURL); @fc-[pv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \}n\cUy-  
httpConnection.setRequestProperty("User-Agent","NetFox"); g!\H^d4  
String sProperty = "bytes="+nStartPos+"-"; @BmI1  
httpConnection.setRequestProperty("RANGE",sProperty); !S3^{l-  
Utility.log(sProperty); "M !]t,?S  
f'oO/0lx  
sOyL  
InputStream input = httpConnection.getInputStream(); ^cnTZzT#Q  
//logResponseHead(httpConnection); z|$M,?r'  
l"rX'g?  
:u9OD` D  
byte[] b = new byte[1024]; ~z kzuh  
int nRead; JE *d-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) bl3?C  
{ $ o }  
nStartPos += fileAccessI.write(b,0,nRead); MtD0e@  
//if(nThreadID == 1) Mp7X+o/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }`~n$OVx  
} ,6 IKkyD  
@dyh: 2!  
&E+mXEve  
Utility.log("Thread " + nThreadID + " is over!"); 6KRC_-  
bDownOver = true; ogvB{R  
//nPos = fileAccessI.write (b,0,nRead); QG=K^g  
} II'"Nkxd  
catch(Exception e){e.printStackTrace ();} 9R m\@E [  
} xjy(f~'  
} 8-PHW,1@a3  
,gdud[&|;  
rQD^O4j R  
//打印回应的头信息 q"e]\Tb=we  
public void logResponseHead(HttpURLConnection con) YvG=P<_xw  
{ 2 oo/KndU  
for(int i=1;;i++) `tPVNO,l  
{ 6Qk[TL)t  
String header=con.getHeaderFieldKey(i); l86gs6>  
if(header!=null) DS1{~_>nFu  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]SmN}Iq1  
Utility.log(header+" : "+con.getHeaderField(header)); Miz?t*|{[  
else ;O7Vl5R  
break; i*((@:  
} #M)+sK$H%f  
} ]5r@`%9  
!T#EkMM  
1{A K=H')  
public void splitterStop() jx{wOb~oO)  
{ z*UgRLKZD  
bStop = true; )*XD"-9  
} v&qL r+_7  
2e9.U/9  
ifcp!l+8  
} \iP5.3C  
_CMNmmp`e  
7Fx0#cS"\  
/* Yi j^hs@eV  
**FileAccess.java hXh nJ  
*//文件访问(定位,写) Ae[fW97  
package NetFox; SLW|)Q24  
import java.io.*; {2)).g  
h343$,))u  
b_X&>^4Dkl  
public class FileAccessI implements Serializable{ `W:z#uNG]  
~1&WR`U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Ew JNpecX  
RandomAccessFile oSavedFile; TM5 Y(Q*  
long nPos; N%F4ug@i   
suS[P?4  
@THa[|(S  
public FileAccessI() throws IOException LS$zA>:  
{ +s;>@j()V  
this("",0); k<|}&<h  
} 9:*[Q"v  
6>]w1 H  
;0U*N& f  
public FileAccessI(String sName,long nPos) throws IOException HbRvU}C1  
{ >6R3KJe  
oSavedFile = new RandomAccessFile(sName,"rw"); r )HZaq  
this.nPos = nPos; /9=r.Vxh  
oSavedFile.seek(nPos); oY+p;&H  
} N% ?R(  
_X|prIOb=  
2EO x],(|  
public synchronized int write(byte[] b,int nStart,int nLen) s"XwO8yhM  
{ fy$?~Ji &  
int n = -1; Eq%f`Qg+1E  
try{ ^ L]e]<h(  
oSavedFile.write(b,nStart,nLen); I~;w Q  
n = nLen; { V) `6  
} +0?1"2  
catch(IOException e) D4\[D8pD  
{  fDloL  
e.printStackTrace (); H,c`=Ii3  
} K9-9 c"cz  
Cv@)tb  
n.rn+nuwv  
return n; nEUUD3a  
} ps;dbY*s6  
\%7fm#z6  
Y]7503J  
} ,kf.'N  
^|SiqE  
RRXp9{x`  
/* 51u\am'T  
**SiteInfoBean.java @dUN3,}  
*/ ?;_*8Doq-a  
package NetFox; 1BEs> Sm  
'$c9S[  
`yP`5a/  
public class SiteInfoBean { g60k R7;\  
+TyN;e   
P@keg*5@  
private String sSiteURL; //Site's URL h!ogH >S~  
private String sFilePath; //Saved File's Path damG*-7Svx  
private String sFileName; //Saved File's Name tS>^x  
private int nSplitter; //Count of Splited Downloading File $_iE^zZaU^  
4&=</ok6`0  
JEk'2Htx  
public SiteInfoBean() <:Mz2Rg  
{//nSplitter的缺省值为5 aU~?&]  
//default value of nSplitter is 5 E%DT;1  
this("","","",5); 3%bhW9H%  
} ] j8bv3  
d!UxFY@  
-pIz-*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }lDX3h  
{ 7FJ4;HLQ  
sSiteURL= sURL; c -PZG|<C[  
sFilePath = sPath; TZ+ p6M8G  
sFileName = sName; )|vy}Jf7  
this.nSplitter = nSpiltter; s[sv4hq  
14" 57Jt8  
J jm={+@+  
} 3LT~- SvL  
w|6/i/X  
q" f65d4c  
public String getSSiteURL() vc&v+5Y  
{ pY@QR?F\  
return sSiteURL; !6 L!%Oi  
} Pmo<t6  
:dh; @kp  
&92/qRh7  
public void setSSiteURL(String value) tsJR:~  
{ oX8EY l  
sSiteURL = value; mEbI\!}H0  
} e b} P/  
@lF?+/=$  
t^KQ*8clG  
public String getSFilePath() . }/8 ]  
{ Ny^f'tsA  
return sFilePath; }%8ZN :  
} FGx)?  
p<=Lh47 =  
mf3,V|>[\  
public void setSFilePath(String value) '9Z`y_~)G  
{ cZQ8[I  
sFilePath = value; W~0rSVD$<z  
} 5h&sdzfG  
aZ4?! JW.  
9-/q-,  
public String getSFileName() aTTkj\4  
{ RARA_tii  
return sFileName; 50QDqC-]XS  
} k9f|R*LM  
(0 H=f6N  
C@6:uiT$  
public void setSFileName(String value) 7H5VzV  
{ zQ |2D*W  
sFileName = value; [9${4=Kq  
} J?w_DQa  
XZ~kXE;B(  
YD'gyP4  
public int getNSplitter() XQ]vJQYIR  
{ Q $}#&  
return nSplitter; \0x>#ygX  
} XZb=;tYo  
o6px1C:  
6qHD&bv\%C  
public void setNSplitter(int nCount) y\Aa;pL)RQ  
{ Tc/^h 4xH  
nSplitter = nCount; u"=]cBRWL6  
} oj - `G  
} ?@9v+Am!  
D,}bTwRb-  
Ohk\P;}  
/* LDc EjFK(  
**Utility.java NgDhdOB  
*/ 5[Vr {^)  
package NetFox; SK\@w9#&$  
@  W>@6E  
=|]h-[P'  
public class Utility { |y U!d %  
B18BwY  
P|<V0 Vs.  
public Utility() "00j]e.  
{ P!W%KobZ7|  
7P+1W \  
i90X0b-A  
} 'z;(Y*jb  
`s}L3bR]  
//线程睡眠 iz#R)EB/g  
public static void sleep(int nSecond) N!(mM;1X)  
{ ^A@f{g$KB+  
try{ %xlpOR4  
Thread.sleep(nSecond); ] #@:VR  
} *'-4%7C`1  
catch(Exception e) <=">2WP{  
{ b!]O]dk#  
e.printStackTrace (); (p[#[CI9  
} ,Q-,#C"  
} v1,#7s AW'  
N.JR($N$  
//日志 ?>h ~"D#  
public static void log(String sMsg) ChTq!W  
{ '#f<wf n  
System.err.println(sMsg); Iw`tb N L[  
} @KTuG ?.  
<R]m(  
9r].rzf9  
public static void log(int sMsg) R'k `0  
{ >J7slDRo  
System.err.println(sMsg); FMVAXOO  
} /y G34) aB  
} =HCEUB9Fs  
B-MS@ <2  
,a{85HLr]  
/* .t_t)'L  
**TestMethod.java 5G`HJ6  
*/ hI:.Qp`r  
package NetFox; ']1n?K=A  
l;iU9<~  
mH$tG $  
public class TestMethod { <Q~N9W  
r @4A% ql<  
t(#9.b`W)  
public TestMethod() ?XHQdN3e  
{ ///xx/weblogic60b2_win.exe ^aSb~lce  
try{ o pTXI*QA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^v; )6a2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `j>5W<5q\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^cYB.oeu  
fileFetch.start(); #hxYB  
} 5skN'*oG  
catch(Exception e){e.printStackTrace ();} L]kBY2c  
4aS}b3=n  
dEJqgp}\p  
} {$^'oRk  
^O_Z5NbC3  
spV7\Gs.@  
public static void main(String[] args) msmW2Zc  
{ |T|m5V'l  
new TestMethod(); mXRkR.zu+  
} 4-yK!LR  
} CVfV    
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