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http断点续传简单实现(java)

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/* wjGjVTtHs  
**SiteFileFetch.java ~m=%a  
*/ }u*@b10   
package NetFox; YD>>YaH_3@  
import java.io.*; zbKW.u]v  
import java.net.*; (6y3"cbe  
mZJzBYM)  
3e<^-e)+xL  
public class SiteFileFetch extends Thread { QZq9$;>dW  
bB :X<  
= 8e8!8  
SiteInfoBean siteInfoBean = null; //文件信息Bean T7_ SO,X  
long[] nStartPos; //开始位置 tcdn"]#U  
long[] nEndPos; //结束位置 ^%/5-0?xE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +g7nM7,1a  
long nFileLength; //文件长度 %Yn)t3d  
boolean bFirst = true; //是否第一次取文件 av$_hEjo|D  
boolean bStop = false; //停止标志 |MR?8A^"  
File tmpFile; //文件下载的临时信息  s !vROJ  
DataOutputStream output; //输出到文件的输出流 wLp t2b8S  
Tsp-]-)  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) }EG(!)u  
public SiteFileFetch(SiteInfoBean bean) throws IOException p5rRhu/|k3  
{ 4E(5Ccb  
siteInfoBean = bean; <R8Z[H:bV  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); t'/;Z:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _o"3gfH&sJ  
if(tmpFile.exists ()) (dt_ D  
{ DyTk<L  
bFirst = false; ZvKMRW  
read_nPos(); E"yf!*  
} r/<JY5  
else "4AQpD  
{ ^<Tp-,J$EN  
nStartPos = new long[bean.getNSplitter()]; G&H"8REm  
nEndPos = new long[bean.getNSplitter()]; QYb?;Z  
} e%Xf*64  
T1di$8  
PGhZ`nl  
!27]1%Aw  
} U: jf9L2  
h4i $z-!  
;i?!qB>baX  
public void run() Cb-E<W&2D  
{ odn`%ok  
//获得文件长度 qP'g}Pc  
//分割文件 M\6v}kUY  
//实例FileSplitterFetch A>2p/iMc  
//启动FileSplitterFetch线程 JU.%;e7  
//等待子线程返回 Bb"4^EOZ,  
try{ $NRb'   
if(bFirst) # Kr.!uD  
{ E\N=p&g$  
nFileLength = getFileSize();  (t['  
if(nFileLength == -1) e>Y2q|S85  
{ W+S; Do  
System.err.println("File Length is not known!"); 0l@+xS;  
} lM%fgyX  
else if(nFileLength == -2) -B(KQT,J  
{ >D#}B1(!  
System.err.println("File is not access!"); X1dG'PQ  
} 1 *CWHs  
else ,LO-!\L  
{ B9-[wg#0G  
for(int i=0;i<nStartPos.length;i++) ][1u:V/ U  
{ I,3!uogn  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @&B!P3{f  
} 9?c^~77  
for(int i=0;i<nEndPos.length-1;i++) ,e_#   
{ c3t8yifQ  
nEndPos = nStartPos[i+1]; _q4m7C<  
} ='>UKy[=  
nEndPos[nEndPos.length-1] = nFileLength; Cw5K*  
} O3: dOL/C  
} DdO '  
mhuaXbr  
;VRR=p%,  
//启动子线程 5^/[]*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; e_-/p`9  
for(int i=0;i<nStartPos.length;i++) {jf~?/<  
{ ptQ (7N  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0z#kV}wE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9-6_:N>  
nStartPos,nEndPos,i); -"H4brj;G  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  O+j:L  
fileSplitterFetch.start(); :n9^:srGZH  
} H\bIO!vb  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~ }22Dvo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j #YFwX4.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", J@iN':l-  
nEndPos = " + nFileLength); 3Q)>gh*  
// fileSplitterFetch[nPos.length-1].start(); nWu4HFi  
elgQcJ99  
`p|vutk)U  
//等待子线程结束 >#|Yoc  
//int count = 0; EPRs%(w`  
//是否结束while循环 w\*/(E<:  
boolean breakWhile = false; FJ"9Hs2  
hspg-|R  
Am  $L  
while(!bStop) F k;su,]_  
{ CF_!{X_k}  
write_nPos(); n#cN[C9  
Utility.sleep(500); qT @IY)e  
breakWhile = true; f tDV3If  
k;7.qhe:  
mO.U )tL[  
for(int i=0;i<nStartPos.length;i++) I9>*Yy5RNS  
{ q+~CA[H5K  
if(!fileSplitterFetch.bDownOver) {Z.@-Tl_  
{ 2A+,. S_!x  
breakWhile = false; J3;KQ}F.I  
break; n.RhA-O  
} hh&y2#Io  
} 5zOSb$;  
if(breakWhile) B,,d~\  
break; >,Z{wxz J  
-+|[0hpw  
v1)6")8o+  
//count++; Bn q\Gg  
//if(count>4) yw!`1#3.  
// siteStop(); qV,j)b3M  
} w-Fk&dC69  
GR `ncI$z  
2z3A"HrlA  
System.err.println("文件下载结束!"); f*Js= hvO  
} [hbp#I~*[  
catch(Exception e){e.printStackTrace ();} #57z-x[1  
} 0+LloB  
t@M] ec  
gQ#T7  
//获得文件长度 3~rc=e  
public long getFileSize() cU|jT8Q4H  
{ Hc|U@G  
int nFileLength = -1; *pp1Wa7O  
try{ ^^uD33@_  
URL url = new URL(siteInfoBean.getSSiteURL()); +9CUnRv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |pSoBA9U  
httpConnection.setRequestProperty("User-Agent","NetFox"); IoOnS)  
!@k@7~i  
MDt?7c  
int responseCode=httpConnection.getResponseCode(); BxYA[#fd}  
if(responseCode>=400) Xm'K6JH'  
{ 1H7Q[ 2E  
processErrorCode(responseCode); Dj"=kL0  
return -2; //-2 represent access is error I xBO$ 2  
} n4y6Ua9m{  
%;$Y|RbmqE  
_B FX5ifK  
String sHeader; 38i,\@p`9$  
a=VT|CX[  
WEAXqDjM  
for(int i=1;;i++) +Ob#3PRy  
{ );H[lKy  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >nEnX  
//Utility.log(in.readLine()); s;$TX304  
sHeader=httpConnection.getHeaderFieldKey(i); [)vwg`]   
if(sHeader!=null) Cq;d2u0)o$  
{ J?fh3RW9  
if(sHeader.equals("Content-Length")) l}c2l'  
{ mXj Ljgc}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5N<v'6&=  
break; Z"Ni Y  
} i]%"s_l  
} olxP`iK  
else S'p`ECfVMA  
break; KBA%  
} @A'1D@f#  
} e/jM+%  
catch(IOException e){e.printStackTrace ();} rd4'y~#S  
catch(Exception e){e.printStackTrace ();} yt: V+qdv  
5>Yd\(`K  
gi@ji-10  
Utility.log(nFileLength); q.km>XRk~  
wJ*-K-  
[ {LnE:  
return nFileLength; { BL1j  
} IkNt! 2s_  
uA`PZ|  
ER1mA:8>E  
//保存下载信息(文件指针位置) Q.dy $`\  
private void write_nPos() N==_'`O1Q0  
{ s/H"Ab  
try{ 3eP0v  
output = new DataOutputStream(new FileOutputStream(tmpFile)); W+C_=7_  
output.writeInt(nStartPos.length); 8;&S9'ci  
for(int i=0;i<nStartPos.length;i++) Vp"Ug,1  
{ %ab)Gs  
// output.writeLong(nPos); B/kn&^z$|~  
output.writeLong(fileSplitterFetch.nStartPos); ,GP4I3D  
output.writeLong(fileSplitterFetch.nEndPos); \&)W#8V  
} [ c[MQA0  
output.close(); )Hm[j)YI  
} #(g+jb0E  
catch(IOException e){e.printStackTrace ();} #ic 2ofI  
catch(Exception e){e.printStackTrace ();} 05I39/T%  
} ey\{C`(__y  
Ilu`b|%D  
q)xl$*g  
//读取保存的下载信息(文件指针位置) k&iScMgCTH  
private void read_nPos() *oX]=u&  
{  I4f  
try{ yXo0z_ G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); M2P@ &  
int nCount = input.readInt(); q}v04Yy,o  
nStartPos = new long[nCount]; |abst&yp  
nEndPos = new long[nCount]; |QNLO#$ -  
for(int i=0;i<nStartPos.length;i++) 'Mx K}9  
{ 7r[ %| :  
nStartPos = input.readLong(); &W<>^C2v  
nEndPos = input.readLong(); Bd~cY/M  
} 4S0++Hp4  
input.close(); ^@*zH ?Rx{  
} RR"W O  
catch(IOException e){e.printStackTrace ();} Y\Qxdq  
catch(Exception e){e.printStackTrace ();} ])j|<W/  
} \M"^Oe{Dy?  
X >Xp&o  
 QXxLe*  
private void processErrorCode(int nErrorCode) jvc?hUcLKT  
{ '}pgUh_  
System.err.println("Error Code : " + nErrorCode); ' raB  
} iVi3 :7*  
^HlLj#  
%*6oUb  
//停止文件下载 nB@iQxcz  
public void siteStop() $:BK{,\  
{ _[vdY|_  
bStop = true; Lr}b,  
for(int i=0;i<nStartPos.length;i++) ^A "lkV7  
fileSplitterFetch.splitterStop(); ]pRfY9w  
E?gu(\an@  
y.*=Ww+  
} kuj1 2  
} KjwY'aYwr:  
//负责部分文件的抓取 %][$y 7  
**FileSplitterFetch.java [X">vaa  
*/ 1u"*09yZd  
package NetFox; 2~&hstd%  
5hH6G  
AXh3LA  
import java.io.*; L740s[,`o#  
import java.net.*; 60aKT:KLC_  
,8=`*  
yw* mA1v  
public class FileSplitterFetch extends Thread { &<w[4z\  
f*T)*R_  
Y( $Ji12  
String sURL; //File URL @"{'j  
long nStartPos; //File Snippet Start Position 29iIG 'N  
long nEndPos; //File Snippet End Position gF,[u  
int nThreadID; //Thread's ID !&a;P,_Fb  
boolean bDownOver = false; //Downing is over Z ]aK'  
boolean bStop = false; //Stop identical aq0iNbv@  
FileAccessI fileAccessI = null; //File Access interface s@ 2 0#D  
^?s~Fk_V  
~C"k$;(n  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N$,/Q9h^  
{ ;N$0)2w  
this.sURL = sURL; &8Jg9#  
this.nStartPos = nStart; dm,}Nbc91(  
this.nEndPos = nEnd; (,Ja  
nThreadID = id; qF{DArc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;naq-%'Sg  
} NlF0\+h  
rW FcIh5  
{7=WU4$  
public void run() ]~prR?  
{ Y%fVt|  
while(nStartPos < nEndPos && !bStop) 1qLl^DW  
{ ~3'RW0  
z#{ 0;t  
$h 08Z  
try{ Gin_E&%g  
URL url = new URL(sURL); q[)q|R|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]|,q|c,  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5 PGlR!^  
String sProperty = "bytes="+nStartPos+"-"; dSe8vA!)  
httpConnection.setRequestProperty("RANGE",sProperty); b.R!2]T]i^  
Utility.log(sProperty); SLdN.4idK  
Hbjb7Y?[  
vnC<*k4&v  
InputStream input = httpConnection.getInputStream(); RGl=7^M  
//logResponseHead(httpConnection); qY$*#*Q  
v@fe-T&0  
O}K_l1  
byte[] b = new byte[1024]; -t@y\vZF,  
int nRead; b W=.K>|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3!.H^v?  
{ 't|Un G  
nStartPos += fileAccessI.write(b,0,nRead); .~.``a  
//if(nThreadID == 1) pHen>BA[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RIy5ww}3|  
} s&dO/}3uR]  
MX!u$ei  
"U% n0r2  
Utility.log("Thread " + nThreadID + " is over!"); axK6sIxx  
bDownOver = true; + mfe*'AU  
//nPos = fileAccessI.write (b,0,nRead); Uvjdx(fY[a  
} \~@[QGKN  
catch(Exception e){e.printStackTrace ();} *xE"8pN/  
} c=A(o  
} jl.okWuiY  
]#Vo}CVP  
+Lm3vj_ N  
//打印回应的头信息 j+DE|Q&]I  
public void logResponseHead(HttpURLConnection con) 3h9Sz8  
{ ORGv)>C|  
for(int i=1;;i++) bQ-Gp;]  
{ E`Jp(gK9F  
String header=con.getHeaderFieldKey(i); `fBG~NDw  
if(header!=null) -}{%Q?rYj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qQfqlD<  
Utility.log(header+" : "+con.getHeaderField(header)); Sl3KpZ  
else Gb(C#,xbK  
break; nG"tO'J6  
} @+'c+  
} DtzA$|Q}  
{$EH@$./  
g .64Id  
public void splitterStop() D JLiZS  
{ vkd[: CC  
bStop = true; 9=t#5J#O  
} N\9}\Rk@  
3iE-6udCS  
^FP} qW~;9  
} ZCy`2Fir  
3@^MvoC  
tHrK~|  
/* }.0Bl&\UK  
**FileAccess.java ^)&Ly_xrU  
*//文件访问(定位,写) A <4_DVd@@  
package NetFox; +>JdYV<?0  
import java.io.*; 9$Ig~W)  
0:Ar| to$m  
2R^O,Vu*W  
public class FileAccessI implements Serializable{ s %eyW _  
0B=[80K;8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 aSc{Ft/O  
RandomAccessFile oSavedFile; 6!P`XTTE  
long nPos; yGU .AM  
<,\ `Psa)N  
hf;S]8|F  
public FileAccessI() throws IOException q5Fs)B  
{ YiD-F7hf.*  
this("",0); ]JOephX2R  
}  l B1#  
p6`Pp"J_tr  
z< z*Wz  
public FileAccessI(String sName,long nPos) throws IOException 0y)}.'  
{ o4$Ott%Wm  
oSavedFile = new RandomAccessFile(sName,"rw"); gfi AK%  
this.nPos = nPos; /\na;GI$  
oSavedFile.seek(nPos); M70c{s`w5  
} 94\t1fE  
2ck 4C/ h  
Y[2Wt%2\6  
public synchronized int write(byte[] b,int nStart,int nLen) &e5(Djz8t  
{ (=1)y'.  
int n = -1; U4Z[!s$  
try{ MWiMUTZg3  
oSavedFile.write(b,nStart,nLen); 2@vJ  
n = nLen; n5|l|#c$N  
} COR;e`%,  
catch(IOException e) WzjL-a(  
{ yQ9ZhdQS  
e.printStackTrace (); Mtm/}I  
} pe9@N9_5  
d')-7C  
gw"~RV0  
return n; ][,4,?T7  
} BT]ua]T+  
0o;O`/x  
O`WIkBV!  
} >&OUGu|  
#/|75 4]]  
zrs<#8!Y_!  
/* d{f@K71*  
**SiteInfoBean.java -T7%dLHY  
*/ b/t  
package NetFox; } ^i b  
p~K9 B-D  
6R`Oh uN.>  
public class SiteInfoBean { ` @8`qXg  
X APYpBgm  
~4\,&HH  
private String sSiteURL; //Site's URL VU|;:  
private String sFilePath; //Saved File's Path Wqra8u#  
private String sFileName; //Saved File's Name oBA`|yW{U  
private int nSplitter; //Count of Splited Downloading File D==Mb~  
FXV`9uq}Z  
$J.T$0pFa  
public SiteInfoBean() k@V#HC{t  
{//nSplitter的缺省值为5 ,_D" ?o  
//default value of nSplitter is 5 rz%<AF Z  
this("","","",5); \ p4*$  
} -?<4Og[^  
V >Hf9sZ  
;#TaZN  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) l?/Y  
{ !Vheq3"q/  
sSiteURL= sURL; RW_q~bA9  
sFilePath = sPath; 1S0pd-i  
sFileName = sName; 4,G w#@  
this.nSplitter = nSpiltter; +R6a}d/K  
3$VxRz)  
|9Yi7.  
} `Gd$:qV  
!g>.i`  
]u#JuX  
public String getSSiteURL() &.Q8Mi aT  
{ 09S6#;N&  
return sSiteURL; y,=du  
} &3Z?UhH  
:m'+tGs  
vMla'5|l  
public void setSSiteURL(String value) WZZ4]cC  
{ 1zftrX~v!X  
sSiteURL = value; ~9=aT1S|  
} w8iR|TV  
@*MC/fe  
FB:<zmwR  
public String getSFilePath() #z!^ <,  
{ aRJcSV  
return sFilePath; Jq ]:<TQ  
} ZDx@^P y  
V-!"%fO.s  
Kmz7c|  
public void setSFilePath(String value) DNkWOY#{  
{ eKN$jlg  
sFilePath = value; Bfr'Zdw  
} iWLa>z|,  
nmFC%p)4  
 npp[@*~  
public String getSFileName() 9bJQT'<R  
{ (\a6H2z8l  
return sFileName; tNIlzR-  
} s%pfkoOY%  
] asBd"  
dQb.BOI)h  
public void setSFileName(String value) N ]N4^A'  
{ Nt:9MG>1  
sFileName = value; LfLFu9#:w  
} ;heHefbvvd  
x;\wY'  
8K9$,Ii  
public int getNSplitter() Ucdj4[/,h  
{ T]T;$  
return nSplitter; }_ mT l@*  
} 4~z?"  
?BA^YF  
PX(p X>  
public void setNSplitter(int nCount) 8|Y.|\  
{ "YU{Fkl#j  
nSplitter = nCount; |=a}iU8  
} J#2!ZQE 3  
} ? 1*m,;Z  
:-`7Q\c}  
"xRBE\B  
/* oslJC$cy'  
**Utility.java a`(a)9i  
*/ =PHIpFIuk  
package NetFox; 7piuLq+  
!T,AdNa8  
8}e,%{q  
public class Utility { ul f2vD  
hsKmnH@#  
fV:4#j  
public Utility() D4JLtB'=  
{ TXXy\$  
4Kwh?8.  
WQNE2Q  
} f:B>zp;N  
;Lm=dd@S:  
//线程睡眠 5kNzv~4B,;  
public static void sleep(int nSecond) SLfFqc+n0  
{ 'CZa3ux  
try{ X|D!VX>#!  
Thread.sleep(nSecond); l`-bFmpA  
} u{N,Ib 8  
catch(Exception e) ;6ecrQMw&  
{ mo{MR:>)  
e.printStackTrace (); ._9 n~=!  
} R9rj/Co  
} jjM\.KL]  
OS|>t./U  
//日志 C[!MS5  
public static void log(String sMsg) wCf~O'XLw  
{ {O<l[|Ip  
System.err.println(sMsg); C:8_m1Y{  
} :,b iyJt  
{gNV[45  
>gwz,{  
public static void log(int sMsg) 0 [?ny`Y  
{ &UCsBqIY  
System.err.println(sMsg); K_?W\Yg   
} 38DT2<qC  
} 0$+fkDf  
G 0O#/%%  
Vm}%ttTC  
/* #rO8Kf  
**TestMethod.java XdLCbY  
*/ #GDe0 8rOw  
package NetFox; m'\2:mDu0  
<<](XgR(  
mkh"Kb*{  
public class TestMethod { Ch$*Gm19Z  
jcNT<}k C  
'I;!pUfVp  
public TestMethod() km^^T_ M/  
{ ///xx/weblogic60b2_win.exe Ofm%:}LV  
try{ n+lOb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); V7G7&'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )irRO8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Y HSYu  
fileFetch.start(); "8^5>EJWv  
} u]u[(K5F  
catch(Exception e){e.printStackTrace ();} 6hZ@;Q=b  
G7--v,R1x  
ZCKka0*  
} bl_H4  
y2]-&]&  
ydw)mT44K  
public static void main(String[] args) X U/QA [K  
{ c|F[.;cR  
new TestMethod(); XNQAi (!GS  
} ,QzL)W7  
} 7\*FEjRM]  
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