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http断点续传简单实现(java)

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/* w{Dk,9>w)  
**SiteFileFetch.java 9h~>7VeZ)  
*/ # {!Qf\1M  
package NetFox; {$Fg+~   
import java.io.*; "1`c^  
import java.net.*; HiVF<tN  
9I9J}&4  
ggX'`bK  
public class SiteFileFetch extends Thread { v#D9yttO{  
dkRJ^~  
,uuQj]Dac+  
SiteInfoBean siteInfoBean = null; //文件信息Bean QJ pUk%Wj  
long[] nStartPos; //开始位置 <W\~A$  
long[] nEndPos; //结束位置 k(hes3JV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 GQ)hZt0  
long nFileLength; //文件长度 Lsuc*Ps  
boolean bFirst = true; //是否第一次取文件 Z/56JYt!~  
boolean bStop = false; //停止标志 7c<2oTN'  
File tmpFile; //文件下载的临时信息 CWt,cwFW  
DataOutputStream output; //输出到文件的输出流 ^K&& O {  
Z\O ,9  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) m5f/vb4l  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~])\xC  
{ [#uX{!q'  
siteInfoBean = bean; h^34{pKDn  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^|as]x!sv  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jlzqa7  
if(tmpFile.exists ()) l0[jepmpiT  
{ *1}9`$  
bFirst = false; a*74FVZo.;  
read_nPos(); [-1Nn}  
} t'0r4&\  
else QoI@/ jLj  
{ 8R8J./i.K  
nStartPos = new long[bean.getNSplitter()]; R7Hn8;..  
nEndPos = new long[bean.getNSplitter()]; %=\h=\wt  
} NfS0yQPx  
6Z|/M6f  
(/Z~0hA[Q  
BJ~Q\Si6  
} ObMsncn  
;z)$wH0xc  
0O"GI33Mg  
public void run() @wZ`;J%  
{ D@5&xd_@4  
//获得文件长度 Mz+|~'R  
//分割文件 [,|KVc=&H  
//实例FileSplitterFetch 44RZk|U1J{  
//启动FileSplitterFetch线程 >Mrz$ z{x  
//等待子线程返回 ANp4yy+  
try{ bo\|mvB~  
if(bFirst) 2P@>H_JFF  
{ ,N <;!6e  
nFileLength = getFileSize(); @MAk/mb&  
if(nFileLength == -1) Fov/?:f$  
{ %!p14c*J H  
System.err.println("File Length is not known!"); *Rr,ii  
} 0!_D M^3  
else if(nFileLength == -2) "`C|;\w  
{ f1hi\p0q  
System.err.println("File is not access!"); OQ W#BBet@  
} ^7F!>!9Ca  
else k$k (g  
{ BAdHGwomh  
for(int i=0;i<nStartPos.length;i++) =@gH$Q_1  
{ ^?&Jq_oU  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z UAWSJ,s  
} 7b:oz3?PI  
for(int i=0;i<nEndPos.length-1;i++) =u${2=  
{ JS}W4 N  
nEndPos = nStartPos[i+1]; |@Q(~[It  
} . I {X  
nEndPos[nEndPos.length-1] = nFileLength; ' OdZ[AN  
} /=,^fCCN  
} N;Hrc6nin^  
V{ra,a*  
) 8st  
//启动子线程 w v9s{I{P  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~;wSe[  
for(int i=0;i<nStartPos.length;i++) Q:>;d-D|1  
{ NTs< ;ED  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V\ !FD5%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %jqBYn0q'  
nStartPos,nEndPos,i); 0wAZ9AxA{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %zb7M%dC6`  
fileSplitterFetch.start(); "&Q-'L!M'/  
} 3vQ?vS|2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  ItC*[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); iWGgt]RJ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u?Iop/b  
nEndPos = " + nFileLength); (gl CTF9v  
// fileSplitterFetch[nPos.length-1].start(); K34ca-~  
j3Cpo x  
$J=9$.4"  
//等待子线程结束 { tim{nV  
//int count = 0; \eI )(,A  
//是否结束while循环 f.V0uBDN  
boolean breakWhile = false; #wx0xQ~,J  
I;uZ/cZ|/  
8kH'ai  
while(!bStop) >pG]#Z g  
{ Itj|0PGd  
write_nPos(); \P&'4y~PL  
Utility.sleep(500); g3e\'B'  
breakWhile = true; \>23_d0  
xO"5bj  
:9_K@f?n  
for(int i=0;i<nStartPos.length;i++) =QRLKo#_  
{ $-5iwZ  
if(!fileSplitterFetch.bDownOver) 04WKAP'c N  
{ frc>0\  
breakWhile = false; e9k}n\t3  
break; {LR?#.   
} DK*2 d_  
} O`OntYwa>  
if(breakWhile) ,5t.0XqS  
break; H.O7Y  
_S2QY7/  
 W* `2lf  
//count++; fVb&=%e  
//if(count>4) :g+R}TR[i  
// siteStop();  UZmz k  
} 2ai \("?  
 ]c[80F-  
c .KpXY  
System.err.println("文件下载结束!"); aR*z5p2-w  
} 1wE~dpnx  
catch(Exception e){e.printStackTrace ();} )h2wwq0]  
} gPQ2i])"Q  
e u^z&R!um  
-.ha\t0J  
//获得文件长度 5<,}^4wWZ  
public long getFileSize() Maf!,/U4  
{ c<pr1g  
int nFileLength = -1; 'JKFEUzM  
try{ !;zacw  
URL url = new URL(siteInfoBean.getSSiteURL()); w<-CKM3qe  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t}_qtO7>  
httpConnection.setRequestProperty("User-Agent","NetFox"); v)okVyv  
RUYw D tC  
B07(15y]  
int responseCode=httpConnection.getResponseCode(); |DwI%%0(F  
if(responseCode>=400) 0)yvyQ5  
{ k3}ymhUf  
processErrorCode(responseCode); iN<&  
return -2; //-2 represent access is error yZUB8erb.  
} 8iqx*8}  
6$ 9n_AS  
`fY~Lv{4d_  
String sHeader; ?9OiF-:n  
1i$9x$4~E  
y9pQ1H<F;  
for(int i=1;;i++) M-T&K% /lW  
{ .!l#z|/x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wu/]M~XwI  
//Utility.log(in.readLine()); }yK_2zak5i  
sHeader=httpConnection.getHeaderFieldKey(i); UccnQZ7/I  
if(sHeader!=null) b H?dyS6Bx  
{ 'fy1'^VPAV  
if(sHeader.equals("Content-Length")) u"?cmg<.1  
{ .FXq4who  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ) $#ov-]  
break; e~i ?E  
} mxGa\{D# y  
} `k a!`nfo  
else j42U|CuK  
break; a%Q.8  
} PfF7*}P  
} 5d*k[fZ  
catch(IOException e){e.printStackTrace ();} Uj(,6K8W  
catch(Exception e){e.printStackTrace ();} )?K3nr  
#J\ 2/~  
bJx{mq  
Utility.log(nFileLength); \2L%%M  
t(\d;ybyx  
K0g<11}(Yg  
return nFileLength; 5A>W;Q\4  
} PHyS^J`  
v,KH2 (N  
?Q]&d!U Cs  
//保存下载信息(文件指针位置) '2WYbcU  
private void write_nPos() >C*q  
{ QG4#E$ c  
try{ uV#/Lgw{M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (9*=d_=  
output.writeInt(nStartPos.length); qg 4:Vq  
for(int i=0;i<nStartPos.length;i++) f]h99T  
{ 0"ZB|^c=  
// output.writeLong(nPos); B=(m;A#G  
output.writeLong(fileSplitterFetch.nStartPos); 53=VIN]  
output.writeLong(fileSplitterFetch.nEndPos); "o*F$7D!  
} "c\ZUx_i6  
output.close(); QukLsl]U  
} /E2/3z  
catch(IOException e){e.printStackTrace ();} E@}t1!E<  
catch(Exception e){e.printStackTrace ();} erdWGUfQOe  
} `|8)A)ZVT  
^}ngb Dn  
%i]q} M  
//读取保存的下载信息(文件指针位置) HH&`f3  
private void read_nPos() R.Ao%VT  
{ 1Yo9Wf;vP  
try{ -|~6Zf"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _SJ#k|vcq  
int nCount = input.readInt(); J)6RXt*!  
nStartPos = new long[nCount]; +#"CgZ]  
nEndPos = new long[nCount]; /VgA}[%y  
for(int i=0;i<nStartPos.length;i++) JpvE c!cli  
{ W~$YKBW  
nStartPos = input.readLong(); 1 xm8w$%  
nEndPos = input.readLong(); po}Jwx!  
}  5%mc|  
input.close(); /[#<@o  
} n-be8p)-  
catch(IOException e){e.printStackTrace ();} |bk.gh  
catch(Exception e){e.printStackTrace ();} oP$NTy[  
} *[]7l]XK.  
ZZL.&Ho  
-fI-d1@  
private void processErrorCode(int nErrorCode) Z!0D97^  
{ (|(#~o]40t  
System.err.println("Error Code : " + nErrorCode); ,]gYy00w0s  
} Vahfz8~w/  
X-|Lg.s  
`PXSQf  
//停止文件下载 R3`!Xj#&M  
public void siteStop() (]n^_G#-$  
{ tY-{uHW&h  
bStop = true; .E-)R  
for(int i=0;i<nStartPos.length;i++) (, Il>cR4  
fileSplitterFetch.splitterStop(); +@ga  
2 1.;lj  
HP}d`C5<R  
} GD<xmuo  
} n dgG1v%  
//负责部分文件的抓取 $TyV< G  
**FileSplitterFetch.java 5(R ./  
*/ vY&[=2=  
package NetFox; AP&mr1_  
AC;ja$A#  
;^za/h>r  
import java.io.*; 6,"86  
import java.net.*; ^"WrE(3  
 pbM~T(Y8  
9(g?{6v|  
public class FileSplitterFetch extends Thread { [LDsn]{  
T2|dFKeWG  
zRSIJ!A~  
String sURL; //File URL V +j58Wuf  
long nStartPos; //File Snippet Start Position BO)K=gl;8  
long nEndPos; //File Snippet End Position Q^}6GS$  
int nThreadID; //Thread's ID Goa0OC,  
boolean bDownOver = false; //Downing is over [(Ss^?AJW  
boolean bStop = false; //Stop identical ^EY^.?Mg  
FileAccessI fileAccessI = null; //File Access interface \6~(# y  
y ,e# e`  
k`ulDQu  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qP=4D 9 ]  
{ YTP6m9hA+  
this.sURL = sURL; Wm_:1~  
this.nStartPos = nStart; s @\UZ C  
this.nEndPos = nEnd; Q'xZ\t  
nThreadID = id; oRmz'F  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Al&)8x{p  
}  d(!W  
>S/m(98  
E{+V_.tlu  
public void run() w$%d"Jm#X  
{ gbF^m`A>%+  
while(nStartPos < nEndPos && !bStop) X.TsOoy  
{ hn]><kaA  
GR6BpV7  
/sHWJ?`&/,  
try{  zE$KU$  
URL url = new URL(sURL); zq\YZ:JC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7S+_eL^  
httpConnection.setRequestProperty("User-Agent","NetFox"); \H <k  
String sProperty = "bytes="+nStartPos+"-"; <Sw>5M!j  
httpConnection.setRequestProperty("RANGE",sProperty); 6%'bo`S#  
Utility.log(sProperty); P")duv  
2 VgFP3  
 n *Y+y  
InputStream input = httpConnection.getInputStream(); ;#c=0*.  
//logResponseHead(httpConnection); |cKo#nfzZ  
;oL`fQyr  
Z :51Q  
byte[] b = new byte[1024]; s'/b&Idf8  
int nRead; (vL-Z[M!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Cbw@:+%J{  
{ yc ize2>q  
nStartPos += fileAccessI.write(b,0,nRead); Hqsj5j2i  
//if(nThreadID == 1) @&H Tt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yffg_^fR  
} B5FRe'UC  
^eu={0k  
Qv~KGd9  
Utility.log("Thread " + nThreadID + " is over!"); 0A$x'pU)  
bDownOver = true; {{'GR"D  
//nPos = fileAccessI.write (b,0,nRead); aE]/w1a  
} ZcT%H*Ib]9  
catch(Exception e){e.printStackTrace ();} BT[jD}?  
} CVo2?ZQ  
} 7;]n+QRfm  
>\J({/ #O  
j A/xe  
//打印回应的头信息 $_bhZnYp7  
public void logResponseHead(HttpURLConnection con) ^P)W/2  
{ 70sb{)  
for(int i=1;;i++) jS_fwuM  
{ h?cf)L  
String header=con.getHeaderFieldKey(i); g>g]qQ  
if(header!=null) }ZPO^4H;-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }a=<Gl|I;w  
Utility.log(header+" : "+con.getHeaderField(header)); Ab| t E5%  
else `TugtzRU  
break;  -)='htiU  
} H);O.m  
} ~3 ,>TV  
rUg<(/c  
v$H=~m  
public void splitterStop() iR_j h=2{  
{ d<x7* OW)  
bStop = true; l+%2kR  
} $ NNd4d*  
(Nzup 3j  
j=&]=0F  
} % ~!A,  
!&8nwOG  
WAd5,RZ?  
/* UG@9X/l}  
**FileAccess.java _zuaImJ0o  
*//文件访问(定位,写) ]j=Eof%Rc  
package NetFox; yJyovfJz.  
import java.io.*; {>x6SVF  
*y6zwe !M  
q?&Ap*  
public class FileAccessI implements Serializable{ Z%rMX}  
@ PboT1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @ )bCh(u  
RandomAccessFile oSavedFile; fu=GgD*  
long nPos; IjshxNk  
,b b/ $   
pm)kocG  
public FileAccessI() throws IOException YI877T9>  
{ *h <_gn  
this("",0); E}YJGFB7"  
} t\GoUeH]  
j3W)  
\/wbk`2  
public FileAccessI(String sName,long nPos) throws IOException 26e.Hu  
{ zp4aiMn1F  
oSavedFile = new RandomAccessFile(sName,"rw"); ls;!Og9  
this.nPos = nPos; >e'Hz(~'/  
oSavedFile.seek(nPos); pW y+oZ  
} r bfIH":  
Ro2Ab^rQ|  
XCN^>ToD  
public synchronized int write(byte[] b,int nStart,int nLen) {E 'go]  
{ =%i~HDiy  
int n = -1; C>MEgGP  
try{ y E; n. L  
oSavedFile.write(b,nStart,nLen); g"KH~bN  
n = nLen; N=vb*3ECg  
} 7NFRCCXHQ  
catch(IOException e) ?q*,,+'0  
{ :j<ij]rsI  
e.printStackTrace (); _aaQ1A`p  
} 4#MPD  
j#f7-nHyz8  
+";<Kd-  
return n; [( O*W  
} *LZB.84  
2[V9`r8*  
C/JFb zVx  
} ;_nV*G.y#^  
Fr|Ts>Kx  
SK]"JSY`  
/* \F;  S  
**SiteInfoBean.java Vlf=gP  
*/ R'z -#*[  
package NetFox; &*\-4)Tf  
V,?BVt  
{L#+v~d^'n  
public class SiteInfoBean { G@(ukt`0}  
Kqn{q4L  
HX`>" ?{  
private String sSiteURL; //Site's URL e.n*IJ_fz  
private String sFilePath; //Saved File's Path k@Q>(`  
private String sFileName; //Saved File's Name Iq% 0fX  
private int nSplitter; //Count of Splited Downloading File o_#F,gze)S  
qrLE1b 1$  
hLo>jE  
public SiteInfoBean() Ir4M5OR\  
{//nSplitter的缺省值为5 T!ik"YZ@i  
//default value of nSplitter is 5 66Tx>c"H  
this("","","",5); 713)D4y}  
} W*!u_]K>  
YsBOh{Ml  
&f"kWOe$X  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) OGGuVY  
{ 0Vwl\,7z9  
sSiteURL= sURL; 0,M1Q~u%.  
sFilePath = sPath; 6?uo6 I  
sFileName = sName; ?,AWXiif  
this.nSplitter = nSpiltter; ;p] f5R^  
(q+EP(Q  
H vezi>M  
} J.g4I|{  
]ff5MY 36  
O @)D%*;v  
public String getSSiteURL() 7zWr5U.  
{ w"/RI#7.  
return sSiteURL; ,nnVHBN  
}  o8h1  
O~L/>Ya  
p J#<e  
public void setSSiteURL(String value) w.0:#4  
{ n^+rxG6 L  
sSiteURL = value; cfrvx^,2&  
} A{(<#yRfg  
@`S8d%6P  
mvV5X al  
public String getSFilePath() z&W5@6")`  
{ YjTA+1}  
return sFilePath; +^tw@b  
} XL2iK)A  
etD8S KD  
$9In\ x  
public void setSFilePath(String value) ??g`c=R!V  
{ u''~nSR3&  
sFilePath = value; )<8f3;qd  
} *j/[5J0'M  
O9Fg_qfuT_  
^N2N>^'&1.  
public String getSFileName() yw{;Qm2\7  
{ <-%OXEG  
return sFileName; s"g"wh',  
} xZpGSlA  
l;'#!hC)  
A\S1{JrR  
public void setSFileName(String value) /'uFX,  
{ du0]LiHV  
sFileName = value; q(YFt*(;w  
} @b,&b6V  
'D1Sm&M2%e  
$Afw]F$  
public int getNSplitter() w\f>.N  
{ WUesTA>  
return nSplitter; f:6%DT~a&C  
} XDM~H  
`E4OgO  
ujMics(  
public void setNSplitter(int nCount) .)Af&+KT  
{ fj,]dQ T  
nSplitter = nCount; 7\e96+j|f  
} IQ3]fLb  
} RxZ#`$F  
1E'/!|  
~~D =Z#  
/* 60`4 _Uy]_  
**Utility.java E 02l=M  
*/ |'bRVqJ  
package NetFox; rDvz2p"R  
v!b 8_0~u6  
P O{1u%P  
public class Utility { N)rf /E0  
 #Lq{_Y  
Uq8=R)1<|d  
public Utility() >*"6zR2 o  
{ 1G6MO  
i8Y$cac!  
XA%a7Xtni  
} Q'mLwD3>  
EE<^q?[3^  
//线程睡眠 ~.,h12  
public static void sleep(int nSecond) ZO!  
{ l*+5WrOS  
try{ <P"4Mk7`s  
Thread.sleep(nSecond); $^1L|KgXp  
} 4\6-sL?rW  
catch(Exception e) *xl930y  
{ X%>Sio  
e.printStackTrace (); I )LO@  
} 3nJd0E  
} C<?Huw4R0  
-#nfO*H}  
//日志 jW G=k#WN  
public static void log(String sMsg) Y^(Sc4 W  
{ MGmUgc  
System.err.println(sMsg); K[XFJ9  
} ?5oeyBA@  
F$QAWs  
EpO5 _T_  
public static void log(int sMsg) b BFdr  
{ gtBnP~zT\B  
System.err.println(sMsg); b(Ev:  
} u*<G20~A  
} CX8tTbuFl  
%qM3IVPK)q  
nv9kl Q@  
/* =eXJZPR  
**TestMethod.java ~alC5|wCUQ  
*/ Z !qHL$  
package NetFox; ZN:~etd  
&$vW  
UBUZ}ZIbN  
public class TestMethod { Dw@0P  
]/p)XHKo  
t1)~J  
public TestMethod() Y68T&swD  
{ ///xx/weblogic60b2_win.exe ^r7-|  
try{ l9J]<gG  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0wzq{~\{=_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); I#]$H#}Av  
SiteFileFetch fileFetch = new SiteFileFetch(bean); QX*HvT  
fileFetch.start(); ;(kU:b|j  
} ZjE!? '(ef  
catch(Exception e){e.printStackTrace ();} K,>D%mJ  
X:*Ut3"  
DO!?]"  
} .Jt&6N  
7DU"QeLeb  
rf%E+bh4  
public static void main(String[] args) );^] is~  
{ w/KCu W<  
new TestMethod(); %C]K`=vI-  
} 0Wf,SYx`s  
} {-sy,EYcw  
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