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http断点续传简单实现(java)

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/* 4F3x@H'  
**SiteFileFetch.java &5{xXWJK  
*/ dBV7Te4L  
package NetFox; S\6[EQ65  
import java.io.*; >gKh  
import java.net.*; 88"Sai  
<mMTD8Sx]  
`cQo0{xK  
public class SiteFileFetch extends Thread { kU-t7'?4  
raVA?|'g~  
9~rUkHD  
SiteInfoBean siteInfoBean = null; //文件信息Bean \AUI|M;'  
long[] nStartPos; //开始位置 4Tc&IwR  
long[] nEndPos; //结束位置 Lj\/Ji_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g[>\4B9t  
long nFileLength; //文件长度 "N:XzG  
boolean bFirst = true; //是否第一次取文件 :!;'J/B@..  
boolean bStop = false; //停止标志 kc'pN&]r:  
File tmpFile; //文件下载的临时信息 qa(>wR"mT  
DataOutputStream output; //输出到文件的输出流 UX<Qcjm$e  
;g_> ;tR/  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) cH-@V<  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0qjXQs}  
{ 8E&XbqP+  
siteInfoBean = bean; U`Jy!x2m  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ko&hj XHx  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3bqC\i^[\m  
if(tmpFile.exists ()) =ItkFjhBc  
{ }),w1/#5u8  
bFirst = false; be5,U\&z  
read_nPos(); +(O~]Q-Ez  
} }7G8|54t  
else vB37M@wm  
{ mDGn:oRj  
nStartPos = new long[bean.getNSplitter()]; .*$OQA  
nEndPos = new long[bean.getNSplitter()]; +5.t. d  
} p5O",3,A4  
$qF0ltUQ  
 %d Ernc$  
M L7 \BT  
} /!}'t  
2#X4G~>#h  
O=)  
public void run() S1_6C:^k  
{ Nf3.\eR  
//获得文件长度 G>YAJ o  
//分割文件 4E8JT#&  
//实例FileSplitterFetch EA.D}XC  
//启动FileSplitterFetch线程 C=uZ1xg*,  
//等待子线程返回 H 9 C9P17  
try{ ?::NO Dg  
if(bFirst) #jpoHvt h  
{ c[}(O H  
nFileLength = getFileSize(); ,1q_pep~?%  
if(nFileLength == -1) t3Z_Dp~\  
{ M >:]lpRK  
System.err.println("File Length is not known!"); $(s\{(Wn  
} ^^i6|l1  
else if(nFileLength == -2) +^rh[>W  
{ : "6q,W  
System.err.println("File is not access!"); 4fh^[\  
} E'1+Yq  
else G{aT2c  
{ 53QfTP  
for(int i=0;i<nStartPos.length;i++) U,/6;}  
{ QU{Ech'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); EG'[`<*h  
} DfJ2PX}q  
for(int i=0;i<nEndPos.length-1;i++) [LT^sb  
{ 4@ILw  
nEndPos = nStartPos[i+1]; GwsY-jf  
} ;TQf5|R\K  
nEndPos[nEndPos.length-1] = nFileLength; zWw2V}U!  
} ;vhyhP.oM  
} I4rPHZ|  
aI zv  
/|{,sWf2  
//启动子线程 z!=P@b  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; B bhfG64  
for(int i=0;i<nStartPos.length;i++) Z>F^C}8f  
{ \u`)kJ5o1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HDM<w+ZxX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1rw0sAuGy  
nStartPos,nEndPos,i);  [\)oo  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IC/(R! Crj  
fileSplitterFetch.start(); qv 3^5 d  
} ;S$Ll*f>D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JnD {J`:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <j}lp-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", F9c`({6k  
nEndPos = " + nFileLength); $ E1Tb{'  
// fileSplitterFetch[nPos.length-1].start(); 3HG;!D~m;  
dYFzye  
`U!y&Q$,  
//等待子线程结束 (%ew604X  
//int count = 0; Ue5O9;y]u  
//是否结束while循环 {hSGv   
boolean breakWhile = false; {TSY|D2  
|YJCWFbs8  
@54*.q$  
while(!bStop) #$S}3 o  
{ V BoMT:#  
write_nPos(); jdut4 nFc  
Utility.sleep(500); cl[!`Z  
breakWhile = true; Z{-Lc68  
Df07y<>7Q  
4FeEGySow  
for(int i=0;i<nStartPos.length;i++) }m]q}r  
{ ]rd/;kg.S  
if(!fileSplitterFetch.bDownOver) _cJ[ FP1  
{ =?}twC$  
breakWhile = false; -=$2p0" R  
break; <~Q i67I  
} wjU.W5IR  
} XaI;2fMGI  
if(breakWhile) $Ptk|qFe  
break; E +_&HG}a  
OTvROJP  
a^nAZ  
//count++; S*W;%J5  
//if(count>4) #5CI)4x0!  
// siteStop(); d{+(Lpj^  
} QezSJ io  
85U.wpG  
'E]A.3-Mt  
System.err.println("文件下载结束!"); Iq' O  
} w*LbH]l<-  
catch(Exception e){e.printStackTrace ();} r((Tavn  
} c,5n, i  
AY2:[ 5cm  
q|#MB7e/  
//获得文件长度 e$l 6gY  
public long getFileSize() 4KpL>'Q=  
{ WO</Q6+  
int nFileLength = -1; a0_(eO-S  
try{ ?T*";_o,B  
URL url = new URL(siteInfoBean.getSSiteURL()); )q^ Bj$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;b~~s.+  
httpConnection.setRequestProperty("User-Agent","NetFox"); @ RR\lZ  
<)#kq1b?  
-WR}m6yMr  
int responseCode=httpConnection.getResponseCode(); Pn WD}'0V  
if(responseCode>=400) z]#hWfM4B:  
{ "n?<2 wso  
processErrorCode(responseCode); E20&hc5 8  
return -2; //-2 represent access is error vZjZb(jlN  
} #s"B-sWE  
-CBD|fo[h  
/8eW@IO.F  
String sHeader; tHI*,  
= HE m)  
l1-HO  
for(int i=1;;i++) Eb@MfL  
{ $Ub}p[L  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 981!2*  
//Utility.log(in.readLine()); MW@DXbKVl  
sHeader=httpConnection.getHeaderFieldKey(i); ~77 5soN  
if(sHeader!=null) 'j79GC0  
{ \iZ1W  
if(sHeader.equals("Content-Length")) *T4ge|zUc  
{ epVH.u%  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :kp0EiJ  
break; T T"3^@  
} X <xqT  
} <xF?~7  
else *i?.y*g  
break; hEOJb @:R  
} >eo8  
} T Nci.']  
catch(IOException e){e.printStackTrace ();} \Da~p9 T&  
catch(Exception e){e.printStackTrace ();} :&$Xe1)i]  
a;p6?kv  
+{ab1))/  
Utility.log(nFileLength); Gg+YfY_  
,4Y sZ  
Mcb<[~m  
return nFileLength; ):E'`ZP!F  
} }}s) +d  
& =sayP  
}rxFS <j  
//保存下载信息(文件指针位置)  * D3  
private void write_nPos() +-k`x0v  
{ 2o}8W7y  
try{ -9Xw]I#QR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *<3iEeO/R  
output.writeInt(nStartPos.length); -AeHY'T  
for(int i=0;i<nStartPos.length;i++) qq>44k\|)  
{ ]eL~L_[G\  
// output.writeLong(nPos); ndt8=6p  
output.writeLong(fileSplitterFetch.nStartPos); )XZ,bz*jn  
output.writeLong(fileSplitterFetch.nEndPos); ]=pWZ~A  
} ,,2_/u\"/i  
output.close(); +{bh  
} T/3;NXe6E  
catch(IOException e){e.printStackTrace ();} 6!o/~I#  
catch(Exception e){e.printStackTrace ();} <sF!]R&4  
} ,|>nF;.Y  
m&{rBz0  
QD6Z=>?S  
//读取保存的下载信息(文件指针位置) F6h/0i  
private void read_nPos()  pe|\'<>i  
{ .y(@Y6hO  
try{ D`5: JR-{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); r6/<&1[  
int nCount = input.readInt(); ^&e;8d|f{  
nStartPos = new long[nCount]; r]Z.`}Kkm  
nEndPos = new long[nCount]; [kQ"6wh8  
for(int i=0;i<nStartPos.length;i++) lK 9s0t'  
{ !vi4* @:  
nStartPos = input.readLong(); LIc*tsl  
nEndPos = input.readLong(); gS0,')w  
} H==X0  
input.close(); +._f.BRmX.  
} mRNHq3  
catch(IOException e){e.printStackTrace ();} ZO]E@?Oav  
catch(Exception e){e.printStackTrace ();} i,^>uf  
} I-j(e)P(o_  
4t"*)xy  
:Fq2x_IUE  
private void processErrorCode(int nErrorCode) 30:HRF(:  
{ B&to&|jf  
System.err.println("Error Code : " + nErrorCode); :a#|  
} $=X!nQ& Z|  
&FT5w T  
&*h`b{]  
//停止文件下载 #p;4:IT  
public void siteStop() _ +u sn.  
{ 6uv'r;U]  
bStop = true; eU<]h>2  
for(int i=0;i<nStartPos.length;i++) ajg7xF{l)  
fileSplitterFetch.splitterStop(); XL%vO#YT  
?^F*"+qI  
_&6juBb  
} S+4I[|T]Y  
} HQ jxJd5P  
//负责部分文件的抓取 `Nxo0Q  
**FileSplitterFetch.java {3_Ffsg`  
*/ lUy*549,  
package NetFox; m&;zLBA;  
LL6ON }  
6Vu}k K)  
import java.io.*; aH~x7N6!  
import java.net.*; D~t"9Z\  
?ZD{e|:u  
4@ydK  
public class FileSplitterFetch extends Thread { Q)7L^  
k1@  A'n  
<%5-Pzp  
String sURL; //File URL D:S6Mu  
long nStartPos; //File Snippet Start Position H@OrX  
long nEndPos; //File Snippet End Position D|8sjp4  
int nThreadID; //Thread's ID -O5(%  
boolean bDownOver = false; //Downing is over d[qEP6B  
boolean bStop = false; //Stop identical 2*3B~"  
FileAccessI fileAccessI = null; //File Access interface 8kn]_6:3i  
8{U]ATx'(  
Sj=69>m]5  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vb80J<4  
{ ?Pok-90  
this.sURL = sURL; Wtzj;GJj  
this.nStartPos = nStart; Xk$l-Zfse  
this.nEndPos = nEnd; !<UEq`2  
nThreadID = id; bl!f5ROS(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 N4JqW  
} ^7^bA  
`!>dbR&1  
s5Bmv\e.i5  
public void run() JWm^RQ  
{ Bafz&#;Q'  
while(nStartPos < nEndPos && !bStop) r &l*.C*  
{ 9OO_Hp#|9  
Kr}M>hF+|  
PU/Br;2A  
try{ IP4b[|ef  
URL url = new URL(sURL); G:6$P%.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >Qbc(}w  
httpConnection.setRequestProperty("User-Agent","NetFox");  lN`_0  
String sProperty = "bytes="+nStartPos+"-"; ,B/p1^;.  
httpConnection.setRequestProperty("RANGE",sProperty); -GkK[KCH  
Utility.log(sProperty); RNrYT|  
>a`zkl  
QGCdeE$K  
InputStream input = httpConnection.getInputStream(); +]~w ?^h  
//logResponseHead(httpConnection); pQ-^T.'  
E{]|jPdr  
 _I}L$  
byte[] b = new byte[1024]; R_*D7|v  
int nRead; pN f9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &)f++(i  
{ R&|)y:bg|  
nStartPos += fileAccessI.write(b,0,nRead); 1S.e5{  
//if(nThreadID == 1) dK(%u9v  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U.j\u>a  
} V1b_z  
*Wo$ $T  
41Q   
Utility.log("Thread " + nThreadID + " is over!"); a:%5.!Vd  
bDownOver = true; a4qpnr]0  
//nPos = fileAccessI.write (b,0,nRead); W yJfF=<  
} Nb9V/2c;V  
catch(Exception e){e.printStackTrace ();} 88=FPEU  
}  Dmv  
} C`T5d  
=|&"/$+s  
f(MHU   
//打印回应的头信息 M=abJ4  
public void logResponseHead(HttpURLConnection con) l \n:"*To  
{ #V,~d&_k  
for(int i=1;;i++) f I-"8f0_  
{ &EJ,k'7$  
String header=con.getHeaderFieldKey(i); ]B'  
if(header!=null) WHavz0knf[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1Kf t?g  
Utility.log(header+" : "+con.getHeaderField(header)); k<";t  
else ^^Q32XC,  
break; `ip69 IF2*  
} Ywk[VD+.  
} MC)W?  
R/xCS.yl}  
cYn}we}7  
public void splitterStop() &r%^wfp  
{ ZUI9[A?  
bStop = true; V+ ~2q=  
} $=SYssg7La  
8/$iCW  
dY` J,s  
} PCnJ2  
DJjDKVO5t  
J|8YB3K,  
/* :@A;!'zpL  
**FileAccess.java ):EXh#  
*//文件访问(定位,写) 0nnq/u^  
package NetFox; k6XmBBIj-  
import java.io.*; -7VV5W  
I T2sS6&R  
3H %WB|  
public class FileAccessI implements Serializable{ %b4(wn?n:B  
EPnB%'l\c  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 SntYi0,`  
RandomAccessFile oSavedFile; hd%F7D5  
long nPos; 5R G5uH/-<  
]>T/Gl1  
F4gc_>{|  
public FileAccessI() throws IOException hIr^"kVK  
{ HjR<4;2  
this("",0); Hf|:A(vCx  
} l6Bd<tSH  
YHAg4 eb8  
P*sCrGO%  
public FileAccessI(String sName,long nPos) throws IOException Rx2|VD  
{ "S#hzrEdYI  
oSavedFile = new RandomAccessFile(sName,"rw"); 7J/3O[2  
this.nPos = nPos; aX:$Q }S  
oSavedFile.seek(nPos); "ET"dMxU  
} 1Xc%%j  
7|Y8^T s  
nJC}wh2d#  
public synchronized int write(byte[] b,int nStart,int nLen) `r Ql{$9IC  
{ e0 EJ[bG  
int n = -1; 4{E=wg^p  
try{ Vtri"G8 aB  
oSavedFile.write(b,nStart,nLen); &ayoTE^0,  
n = nLen; HrxEC)V6#  
} +M:Q!'  
catch(IOException e) Pp!W$C:  
{ p {3|W<  
e.printStackTrace (); dGjvSK<1@  
} d?.x./1[qi  
ysPW<  
\ 3N#%  
return n; 4F?1,-X  
} K.~U%v}  
,5:86'p  
In2D32"F  
} f [D#QC  
^xrR3m*d  
duCm+4,.  
/* DGnswN%n1  
**SiteInfoBean.java xB#E&}Ho  
*/ N8TO"`wdbs  
package NetFox; }2S \-  
0a5P@;"a  
19_F\32  
public class SiteInfoBean {  CgWj9 [  
Oc>-jhx?  
_1~Sj*  
private String sSiteURL; //Site's URL (@Bm2gH  
private String sFilePath; //Saved File's Path aum,bm/0J  
private String sFileName; //Saved File's Name Hw Is7  
private int nSplitter; //Count of Splited Downloading File F 7=-k/k  
yY+2;`CH  
Velmq'n  
public SiteInfoBean() ='FEC-f95  
{//nSplitter的缺省值为5 uH#NJoR O  
//default value of nSplitter is 5 @N$r'@  
this("","","",5); k)J7) L  
} {SJLM0=Z  
VF-d^AGt  
#3S/TBy,  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z7v~;JzC#  
{ LLE~V~j  
sSiteURL= sURL; > h9U~#G=  
sFilePath = sPath; ra3WLK  
sFileName = sName; d3\8BKp  
this.nSplitter = nSpiltter; ;WhB2/5v  
x[X.// :  
u0,~pJvX  
} WXM_H0K  
P+/L, u  
P/_XDP./U  
public String getSSiteURL() dx~Wm1  
{ ;?rW`e2  
return sSiteURL; %bsdC0xM  
} U{x'@/Ld  
^~0 r+w61  
(Cq-8**dY  
public void setSSiteURL(String value) #yqcUbJY0R  
{ Hq~ 2,#Ue  
sSiteURL = value; ovl@[>OB  
} >eXNw}_j  
B[$e;h*Aw[  
m4iR '~L}  
public String getSFilePath() h3:,Gbyap  
{ ]u:NE'0Xy  
return sFilePath; L]V K9qB  
} 7+c@pEU]  
G$Dg*<  
y`N1I  
public void setSFilePath(String value) B4b UcYk  
{ >8VJ!Kg4  
sFilePath = value; (T^aZuuS  
} <I>q1m?KN  
HG^8&uh]  
*D'V W{  
public String getSFileName() U!Lws#\X  
{ o%dtf5}(,  
return sFileName; /i]Gg \)  
} $lv  g.u  
X2{3I\'Ft  
^8 z*f&g  
public void setSFileName(String value) J:>TV.TP  
{ ^a(q7ZfY  
sFileName = value; |9g*rO  
} ]/a?:24[  
ZpZ~[BtQ  
K)k!`du!6  
public int getNSplitter() V +hV&|=  
{ Fm@GU  
return nSplitter; `R^)< v*  
} A^~\  
3"B|w^6'2  
A[b'MNsv  
public void setNSplitter(int nCount) cO <x:{`  
{ rg $71Ir  
nSplitter = nCount; )S`A+M K]  
} !~RD>N&n  
} J3$ihH.  
%~eZrG.  
# ><.zZ  
/* fpzTv3D=I  
**Utility.java ?6[>HX;  
*/ ]\GGC]:\@  
package NetFox; {d3r>Ub)7d  
<}e<Zf!  
2Gj&7A3b  
public class Utility { yXkgGY5  
ZJx:?*0a  
s*VZLKO  
public Utility() u!F3Rh8D  
{ aC:rrS  
UH)A n:9  
c~>M7e(  
} \Q#F&q0  
h[ t OY  
//线程睡眠 Y H?>2u  
public static void sleep(int nSecond)  Im#3sn  
{ \Oc3rJ(  
try{ +tuC845  
Thread.sleep(nSecond); #-@dc  
} pa.W-qyu  
catch(Exception e) s(zG.7*3n  
{ k1]?d7g$w  
e.printStackTrace (); x*_c'\F|  
} }U8H4B~UtY  
} Lrz>00(*4  
=LuA [g  
//日志 6~}=? sX4  
public static void log(String sMsg) h883pe=  
{ e#08,wgW  
System.err.println(sMsg); &oAuh?kTq  
} i8 dv|oa  
ty(F;M(  
{lqnn n3  
public static void log(int sMsg) l_$~~z ~  
{ T8ZsuKio]  
System.err.println(sMsg); ]T+{]t  
} ^gNAGQYA  
} 7|H !(a'  
)82x)c<e  
g{dyDN$5|w  
/* \ <V{6#Q=  
**TestMethod.java ]2tX'=X  
*/ ,u! c|4  
package NetFox; tV%M2 DxS  
Y]ZOvA5W  
fNQ.FAK":  
public class TestMethod { taI])  
?. CA9!|   
1)M3*h3  
public TestMethod() ba|~B8rII[  
{ ///xx/weblogic60b2_win.exe nz+DPk["  
try{ trg+" )a  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YS/{q~$t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [O9(sWL'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); nB"q  
fileFetch.start(); ^- mz!{  
} 8!E$0^)c|  
catch(Exception e){e.printStackTrace ();} pX|\J>u)  
|fq1Mn8  
#;>J<>  
} m?bb/o'B  
Spt[b.4mF  
_q M'm^z5  
public static void main(String[] args) pn>zuH e  
{ $0NWX  
new TestMethod(); ,~%Qu~\  
} 7DXT1+t  
} ^pAqe8u_  
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