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http断点续传简单实现(java)

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/* (GcKaUg8*  
**SiteFileFetch.java io r [v  
*/ .4C[D{4  
package NetFox; Ie&b <k  
import java.io.*; eMl]td rI  
import java.net.*; E?gu(\an@  
FO(0D?PCR  
-Xxu/U})%  
public class SiteFileFetch extends Thread { <\d|=>;  
1u"*09yZd  
2~&hstd%  
SiteInfoBean siteInfoBean = null; //文件信息Bean /q"d`!h)w  
long[] nStartPos; //开始位置 sE%<"h\_0  
long[] nEndPos; //结束位置 L740s[,`o#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 60aKT:KLC_  
long nFileLength; //文件长度 Q f+p0E;  
boolean bFirst = true; //是否第一次取文件 }EedHS  
boolean bStop = false; //停止标志 lO2T/1iMTW  
File tmpFile; //文件下载的临时信息 [71#@^ye  
DataOutputStream output; //输出到文件的输出流 ]oas  
h-b5   
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) h/ X5w4  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1ntkM?  
{ !V]MLA`  
siteInfoBean = bean; *bxJ)9B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }6CXJ+-UR  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /y9J)lx  
if(tmpFile.exists ()) i2FD1*=/?  
{ q1TW?\pjb:  
bFirst = false; fZ6 fV=HEF  
read_nPos(); .mT#%ex  
} "0'*q<8  
else \>Ga-gv6/  
{ /K,|k EE'n  
nStartPos = new long[bean.getNSplitter()]; s !hI:$J.  
nEndPos = new long[bean.getNSplitter()]; Cl t5  
} ||=[kjG~  
Wm$`ae   
2B9 i R  
o4/I1Mq  
}  z _O,Y  
$W/+nmb)@K  
."IJmv  
public void run() ~3'RW0  
{ z#{ 0;t  
//获得文件长度 $h 08Z  
//分割文件 GDHK.?GY  
//实例FileSplitterFetch YA"Ti9-EV  
//启动FileSplitterFetch线程 %kK ][2e  
//等待子线程返回 5 PGlR!^  
try{ dSe8vA!)  
if(bFirst) b.R!2]T]i^  
{ SLdN.4idK  
nFileLength = getFileSize(); 1tc]rC4h  
if(nFileLength == -1) h6\3vfj^f  
{ C(V[wvL  
System.err.println("File Length is not known!"); ~[| V3h4v  
} Xq,UV  
else if(nFileLength == -2) BKC7kDK3H  
{ ceb s.sF:  
System.err.println("File is not access!"); gV"qV   
} =f4[=C$&`  
else \LdmGv@ &  
{ wC(vr.,F  
for(int i=0;i<nStartPos.length;i++) |*tWF! D6`  
{ la\zaKC;>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $hjP}- oUX  
} M&qh]v gC  
for(int i=0;i<nEndPos.length-1;i++) 'dIX=/RZ  
{ v[{8G^Z}54  
nEndPos = nStartPos[i+1]; >d8x<|D  
} b^[W_y  
nEndPos[nEndPos.length-1] = nFileLength; G$;] ?g  
} M5GY>3P$c  
} t."g\;  
c=A(o  
9Fy\t{ks  
//启动子线程 pg~zUOY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -?< Ww{  
for(int i=0;i<nStartPos.length;i++) Pz]bZPHn  
{ 7?=43bZl  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q_&}^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), hrs#ZZ:E  
nStartPos,nEndPos,i); q&XCX$N  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M.ZEqV+k  
fileSplitterFetch.start(); ]d@^i)2LF  
} 4F05(R8k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Zm%VG(l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); kmm  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E rop9T1  
nEndPos = " + nFileLength); r]A" Og_U  
// fileSplitterFetch[nPos.length-1].start(); k}-yOP{  
tcBC!_vF  
xS6(K  
//等待子线程结束 =?/N5O(  
//int count = 0; l GdM80f  
//是否结束while循环 ]2Sfkl0  
boolean breakWhile = false; Guk.,}9  
N\9}\Rk@  
[YC=d1F5  
while(!bStop) 4$yV%[j  
{ TZ?Os4+  
write_nPos(); qqnclqkw&  
Utility.sleep(500); hi!L\yi  
breakWhile = true; m7$8k@r  
A2m_q>> !  
P^ptsZ%  
for(int i=0;i<nStartPos.length;i++) wL4Z W8_  
{ 3/X-Cr+d  
if(!fileSplitterFetch.bDownOver) `J72+RA  
{ 5]jx5!N  
breakWhile = false; )O,wRd>5  
break; 2Y400  
} >(hSW~i~  
} cVO,~I\\  
if(breakWhile) 8g\wVKkTQp  
break; 81~Kpx  
A0G)imsW:_  
v#  
//count++; v`y6y8:>  
//if(count>4) ,Pn-ZF  
// siteStop(); (2UW_l  
} 4L8z>9D  
>; aCf#q  
|#{-.r6Y]  
System.err.println("文件下载结束!"); #@9)h  
} G+0><,S  
catch(Exception e){e.printStackTrace ();} :6XguU  
} /\na;GI$  
6gXIt9B.h$  
l0I}&,+  
//获得文件长度 <lUOJV{&\  
public long getFileSize() _ `H.h6h  
{ >D 97c|?c  
int nFileLength = -1; <"W?<VjO  
try{ dXmV@ Noo  
URL url = new URL(siteInfoBean.getSSiteURL()); ))!Bg?t-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ).LTts7c  
httpConnection.setRequestProperty("User-Agent","NetFox"); fX_#S|DlSG  
!)N|J$FU  
wMGk!N  
int responseCode=httpConnection.getResponseCode(); O7%2v@j|8  
if(responseCode>=400) !<&m]K  
{ *n8%F9F  
processErrorCode(responseCode); # kyl?E  
return -2; //-2 represent access is error oBr.S_Qe  
} gw"~RV0  
o/C(4q6d  
g& k58{e  
String sHeader; )l_@t(_  
$f#agq_  
S=' wJ@?;  
for(int i=1;;i++) MU'@2c  
{ zF8'i=b&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 'Y.Vn P&H  
//Utility.log(in.readLine()); []|;qHhC~(  
sHeader=httpConnection.getHeaderFieldKey(i); D3`}4 A  
if(sHeader!=null) Br}h/!NU/  
{ ({4]  
if(sHeader.equals("Content-Length"))  9:5:`' b  
{ f;gZ|a  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'Gjq/L/x  
break; X APYpBgm  
} Ur^j$B}  
} @9Q2$  
else Ow3P-UzU3  
break; p,F^0OU2}:  
} <\" .L  
} (zG.aaz*C  
catch(IOException e){e.printStackTrace ();} SVagT'BB  
catch(Exception e){e.printStackTrace ();} H6gU?9%  
. V$ps-t  
~]BMrgn  
Utility.log(nFileLength); Bn?:w\%Ue  
YzAFC11,  
%r;w;`/hA  
return nFileLength; ?vgH"W~3>  
} G/vC~6x  
m#f{]+6U  
6"U8V ?E  
//保存下载信息(文件指针位置) -I":Z2.fR  
private void write_nPos() 1S0pd-i  
{ 4,G w#@  
try{ =oX>Ph+ P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'xnnLCm.  
output.writeInt(nStartPos.length); @m~RtC-Q  
for(int i=0;i<nStartPos.length;i++) ;Wc4qJ.@  
{ ]u#JuX  
// output.writeLong(nPos); 8!mc@$Z  
output.writeLong(fileSplitterFetch.nStartPos); jTb-;4 N'  
output.writeLong(fileSplitterFetch.nEndPos); B@O@1?c[  
} N8v'70  
output.close(); Ue*C>F   
} MgJ36zM  
catch(IOException e){e.printStackTrace ();} zP!J/}z  
catch(Exception e){e.printStackTrace ();} `TtXZ[gP}  
} JN'cXZJPn  
GKiukX$'  
{_#yz\j  
//读取保存的下载信息(文件指针位置) QvLZg  
private void read_nPos() 9!U@"~yB  
{ w!SkWS b,~  
try{ 'Z&;uv,l  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4v'A\~ZU  
int nCount = input.readInt(); w,1Ii}d9  
nStartPos = new long[nCount]; 06*rWu9P3  
nEndPos = new long[nCount]; VR5fqf|*  
for(int i=0;i<nStartPos.length;i++) uj|BQ`k  
{ kforu!C  
nStartPos = input.readLong(); bU54-3Ox*  
nEndPos = input.readLong(); }-@4vl x$  
} cK`"lxO  
input.close(); 6rN(_Oi-  
} =Z G:x<Hg  
catch(IOException e){e.printStackTrace ();} tMp=-"  
catch(Exception e){e.printStackTrace ();} %XTcP2pRJ  
} }(XdB:C8  
PX(p X>  
=~KsS }`1,  
private void processErrorCode(int nErrorCode) FG@ -bV  
{ ]@^coj[  
System.err.println("Error Code : " + nErrorCode); m-/j1GZ*  
} gEQNs\Jn L  
[5$w=u"j  
H ?M/mGP  
//停止文件下载 DI|:p!Nx  
public void siteStop() 8Q{9>^  
{ <plC_{Y:wu  
bStop = true; C0*@0~8$9  
for(int i=0;i<nStartPos.length;i++) mTNVU@TY=  
fileSplitterFetch.splitterStop(); (Y% Q|u  
Q&'}BeUbm  
p&-'|'![l  
} e`>{$t  
} U-k VNBs  
//负责部分文件的抓取 5kNzv~4B,;  
**FileSplitterFetch.java LPYbHo3fq  
*/ %ir:AS k  
package NetFox; NS)}6OI3~"  
Z?Hs@j  
dsx]/49<  
import java.io.*; <"D=6jqZ  
import java.net.*; 2F#q I1  
Sn4[3JV$l  
hwN?/5  
public class FileSplitterFetch extends Thread { r7]zQIE  
^u}L;`L  
Cxod[$8  
String sURL; //File URL VQ5nq'{v  
long nStartPos; //File Snippet Start Position >odbOi+X  
long nEndPos; //File Snippet End Position UO*Ymj 1  
int nThreadID; //Thread's ID 'J&f%kx"  
boolean bDownOver = false; //Downing is over p!O(Y6QM  
boolean bStop = false; //Stop identical {U<xdG  
FileAccessI fileAccessI = null; //File Access interface RB* J=  
e!Y0-=?nf#  
uEyH2QO  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException G0u LmW70  
{ 'Jf^`ZT}  
this.sURL = sURL; iRg7*MQu  
this.nStartPos = nStart; @_:]J1jw7  
this.nEndPos = nEnd; N>(g?A; Z+  
nThreadID = id; [gy*`@w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 R8rfM?"W  
} f7h*Vu`>  
D`J6h,=2l/  
Q+b D}emd  
public void run() YEkh3FrbwH  
{ 3d<HN6&U  
while(nStartPos < nEndPos && !bStop) Xc"&0v%;#  
{ ~%?`P/.o  
pfu1 O6R  
E*L iM5+I  
try{ 7eWk7&Xul  
URL url = new URL(sURL); fwK}/0%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;nC.fBu  
httpConnection.setRequestProperty("User-Agent","NetFox"); {hln?'  
String sProperty = "bytes="+nStartPos+"-"; fDG0BNLY  
httpConnection.setRequestProperty("RANGE",sProperty); /Q~gU<  
Utility.log(sProperty); :Mm3 gW)  
>.dWjb6t  
hx/N1 x  
InputStream input = httpConnection.getInputStream(); >^XBa*4;Y  
//logResponseHead(httpConnection); EkGQ(fZ1|  
G8Nt 8U~  
6c^e\0q  
byte[] b = new byte[1024]; h3dsd  
int nRead; dnV[ P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [<'-yQ{l\  
{ dCj,b$  
nStartPos += fileAccessI.write(b,0,nRead); [D*UT#FM  
//if(nThreadID == 1) ?c0xRO%y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rvr-XGK36\  
} Vp>|hj po  
?nP*\8  
t3dlS`O  
Utility.log("Thread " + nThreadID + " is over!"); lFTF ,G  
bDownOver = true; +3KEzo1=)  
//nPos = fileAccessI.write (b,0,nRead); |&Ym@Jyj  
} P-ri=E}>  
catch(Exception e){e.printStackTrace ();} SM`w;?L:?  
} K_K5'2dE  
} wm+/e#'&  
/4xki_}  
k?2k'2dy  
//打印回应的头信息 R'S0 zp6  
public void logResponseHead(HttpURLConnection con) sg+uBCGB  
{ |=&cQRY!p  
for(int i=1;;i++) Yv:55+e!|  
{ B/` !K  
String header=con.getHeaderFieldKey(i); :O(^w}sle  
if(header!=null) Ot]Ru,y->+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <vXGi  
Utility.log(header+" : "+con.getHeaderField(header)); W3iZ|[E;  
else vap,y $C  
break; H<^/Ati,|  
} f%V4pzOc"  
} 8=]Tr3   
\?jeWyo  
3Kn_mL3V-  
public void splitterStop() D}v mwg@3  
{ (&!NC[n,  
bStop = true; &gjF4~W]  
} fJ ,1Ef;Z  
P{u0ftyX}  
e [8LmuIZ  
} 5|1 T}Z#;  
Ox@sI:CT  
~q~MoN<R  
/* CxfRV L`7  
**FileAccess.java &B|D;|7H  
*//文件访问(定位,写) mQY_`&Jq  
package NetFox; s&NX@  
import java.io.*; ,u/aT5\_  
rta:f800z  
EI^06q4x  
public class FileAccessI implements Serializable{ eGX %KT"O  
-Y='_4s  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =MvjLh"s  
RandomAccessFile oSavedFile; FHC \?Cg  
long nPos; f/V 2f].  
kS!viJwtT  
Hbpqyl%O>  
public FileAccessI() throws IOException C?2' +K  
{ 0fYj4`4=n  
this("",0); bP^Je&nS*  
} d$ ^ ,bL2p  
$ >EYhLBa  
t1%_DPD%W  
public FileAccessI(String sName,long nPos) throws IOException 2"B_At  
{ ~I} &V T  
oSavedFile = new RandomAccessFile(sName,"rw"); o";Z$tAJkC  
this.nPos = nPos; rf$X>M=G  
oSavedFile.seek(nPos); 3:C oZ  
} 7R\oj8[  
3#TV5+x*"`  
*q1%IJ  
public synchronized int write(byte[] b,int nStart,int nLen) beu\cV3  
{ =|YxDas  
int n = -1; 8:/e GM  
try{ 9F*+YG!  
oSavedFile.write(b,nStart,nLen); QI3Nc8t_2  
n = nLen; di>cMS 4 c  
} IzpZwx^3''  
catch(IOException e) 1Y]TA3:  
{ UNkCL4N  
e.printStackTrace (); oDU ;E  
} qIAoA .  
Yx>"bv  
nTz6LVF  
return n; J;f!!<l\  
} P`e!Z:  
-Q U^c2  
fOMvj%T@2  
} Q J7L7S  
%C=]1Q=T)  
sn?]n~z  
/* aM$W*- Y  
**SiteInfoBean.java ~mR'Q-hi<  
*/ ](^(=%  
package NetFox; [/BE8]M ~  
HVC >9_:]  
Z%n(O(^L  
public class SiteInfoBean { ]| +<P-  
mb!9&&2 -t  
W[^qa5W<FB  
private String sSiteURL; //Site's URL B0ndcB-  
private String sFilePath; //Saved File's Path w#g#8o>'  
private String sFileName; //Saved File's Name Yp:KI7  
private int nSplitter; //Count of Splited Downloading File T0]*{k(FR  
zD?K>I=  
Jzp#bgq}|  
public SiteInfoBean() <bD>m[8,  
{//nSplitter的缺省值为5 aN,M64F  
//default value of nSplitter is 5 u SR~@Lj ~  
this("","","",5); 'gt-s547  
} j8sH#b7Z  
IEcf  
MXyaE~LK  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5Fz.Y}  
{ <$hu   
sSiteURL= sURL; "hdvHUz  
sFilePath = sPath; o#hjvg  
sFileName = sName; ]J#9\4Sq  
this.nSplitter = nSpiltter; FEJ~k1z  
A<B=f<N3gV  
E.U_W  
} O/!bG~\Y  
5P'p2x#U  
wGZR31  
public String getSSiteURL() \{EpduwZ  
{ &wB\ ~Ie-  
return sSiteURL; :(H>2xS,s  
} %H+\>raLz  
b%Eei2Gm%  
>B>CB3U  
public void setSSiteURL(String value) BY]i;GVq  
{ p^pOuy8  
sSiteURL = value; OGY"<YH6  
} chEn|>~  
A=j0On  
Wn>@9"  
public String getSFilePath() L =8+_0  
{ ?Q72;/$  
return sFilePath; i:l<C  
} ":nQgV\ 9  
$*W6A/%O  
~M(5Ho  
public void setSFilePath(String value) _fwb!T}$  
{ h/,${,}J  
sFilePath = value; JO@|*/mL  
} LE%7DW(  
_H^^y$+1  
SKW%X8  
public String getSFileName() L-9~uM3@\  
{ ~I(Hc.Q  
return sFileName; x+G0J8cW  
} 9RWkm%?  
-$,%f?  
3bNIZ#`|MB  
public void setSFileName(String value) VG>vn`x>a  
{ Z,.G%"i3C  
sFileName = value; ?r2#.W  
} $8crN$ye  
0=="^t_  
c1xrn4f@a  
public int getNSplitter() *;XWLd#  
{ Y+3!f#exm  
return nSplitter; $:of=WTY(  
} 8#D:H/`'  
`4 y]Z)  
8#&q$kE  
public void setNSplitter(int nCount) s-ZI ^I2\  
{ K2<~(78C  
nSplitter = nCount; z~\t|Z]G,|  
} EbZdas!l  
} 5p +ZD7jK  
3or\:  
#YSF&*  
/* &ciN@nJ|$z  
**Utility.java S{K0.<,E  
*/ 8/"fWm/  
package NetFox; q-Qxbg[>e  
P6Mhbmt9*  
7FF-*2@  
public class Utility { _qWliw:0#  
Gc$gJnQio  
WX4;l(P L=  
public Utility() y4Er @8I`  
{ wIf {6z{  
,]5Ic.};p  
_xLHrT!y  
} X1vNF|o~  
HBB{m  
//线程睡眠 DS xUdEK6  
public static void sleep(int nSecond) .6~`Ubr}E  
{ **>/}.%?K  
try{ /xJqJ_70X  
Thread.sleep(nSecond);  LZ~"VV^  
} $M:3XAN  
catch(Exception e) Em7 WDu0  
{ J# kl 7  
e.printStackTrace (); n& $^04+i  
} !JBae2Z  
} {5|("0[F  
|([R'Orm  
//日志 /1`cRyS  
public static void log(String sMsg) }!TL2er_  
{ Bg8#qv  
System.err.println(sMsg); z 5]bia,  
} *{o UWt  
=?X$Yaw*  
` rm?a0  
public static void log(int sMsg) 90xk$3(  
{ BN,>&1I  
System.err.println(sMsg); lHB) b}7E  
} [ REf>_R  
} *xR 2)u  
a8AYcE b  
yA[({2%  
/* x&A vUJ  
**TestMethod.java ,1/}^f6  
*/ [4J6 iF  
package NetFox; De_C F8  
V#q}Wysft  
MP>n)!R[`  
public class TestMethod { e &9F\e  
@uH#qg7  
_DP|-bp D  
public TestMethod() ~svO*o Wa  
{ ///xx/weblogic60b2_win.exe Vc3mp;6"  
try{ gX5&d\y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); H0"=Vs,n  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "gW7<ilw  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5f:DN\ ]  
fileFetch.start(); XUV!C 7  
} i.1U|Pi  
catch(Exception e){e.printStackTrace ();} DDd|T;8  
 StYzGJ  
VK3it3FI>3  
} o5aLU Wi-  
9TxyZL   
as"N=\N  
public static void main(String[] args) /\Q*MLwD  
{ =wq;@'U  
new TestMethod(); r(2 R <A  
} 'PWQnt_U  
} s4T}Bs r  
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