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http断点续传简单实现(java)

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/* Zf [#~4  
**SiteFileFetch.java ;v=v4f'+  
*/ 6.0/asN}  
package NetFox; !=t.AgmL  
import java.io.*; kH9fK80  
import java.net.*; hp< NVST  
K[G=J  
rO;Vr},3\%  
public class SiteFileFetch extends Thread { .~L^h/)Gjy  
'UN 'gXny  
08pG)_L  
SiteInfoBean siteInfoBean = null; //文件信息Bean ?A\[EI^  
long[] nStartPos; //开始位置 O.+02C_*  
long[] nEndPos; //结束位置 uLK4tQ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7L"Pe'Hw  
long nFileLength; //文件长度  +bC=yR  
boolean bFirst = true; //是否第一次取文件 r'/H3  
boolean bStop = false; //停止标志 rF>7 >wq  
File tmpFile; //文件下载的临时信息 FsXqF&{  
DataOutputStream output; //输出到文件的输出流 N:]Ud(VRM  
3R|C$+Sc  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) +. `  I  
public SiteFileFetch(SiteInfoBean bean) throws IOException )8244;  
{ ybNy"2Wk  
siteInfoBean = bean; /E|Ac&Qk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7Ns1b(kU  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _1sjsGp>  
if(tmpFile.exists ()) 1|8<!Hx#-  
{ |mO4+:-~D+  
bFirst = false; >kN%R8*Sx  
read_nPos(); 5kju{2`GF  
} 99]&Xj  
else CKau\N7T  
{ k5X& |L/  
nStartPos = new long[bean.getNSplitter()]; rERHfr`OU  
nEndPos = new long[bean.getNSplitter()]; ySXQn#}-,  
} `dpm{s n  
U`HSq=J  
:t#N.[=&#  
0**.:K<i  
} \A'tV/YAd  
D$OUy}[2`.  
8E:d!?<^&I  
public void run() {YoK63b$  
{ q=+AN</  
//获得文件长度 \as^z!<  
//分割文件 'GJ'Vli  
//实例FileSplitterFetch p~!UE/V  
//启动FileSplitterFetch线程 fSL'+l3  
//等待子线程返回 7yDWcm_y  
try{ G$HXc$OY  
if(bFirst) Y8$,So>~  
{ _,C>+dv)  
nFileLength = getFileSize(); 0wlKBwf`J  
if(nFileLength == -1) S7fX1y[  
{ ]= EYju@  
System.err.println("File Length is not known!"); @UG%B7  
} o[ua$+67E  
else if(nFileLength == -2) kbHfdA  
{ JJ=%\j  
System.err.println("File is not access!"); 7B"*< %<  
} $Z2Y%z6y  
else 4{Q{>S*h  
{ ivb?B,Lz0  
for(int i=0;i<nStartPos.length;i++) =Co[pt  
{ q0a8=o"|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I\FBf&~  
} "-U`E)]w*[  
for(int i=0;i<nEndPos.length-1;i++) <hA1[S}  
{ Qv`Lc]'  
nEndPos = nStartPos[i+1]; 1q Jz;\wU  
} aGRD`ra  
nEndPos[nEndPos.length-1] = nFileLength; 8qi6>}A  
} 6bXP{,}Gp  
} =OUms@xcE  
n(}zq  
XX:?7:j}[8  
//启动子线程 f'>270pH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8M DX()Bm  
for(int i=0;i<nStartPos.length;i++) ~s[St0  
{ Ld?-Ik~fF>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  \W',g[Y:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `1T?\  
nStartPos,nEndPos,i); -? |-ux  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U/|;u;H=  
fileSplitterFetch.start(); %JsCw8C6?  
} MS~|F^g  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %9qG|A,cA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); F6$QEiDu@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", A3Lfh6O  
nEndPos = " + nFileLength); jZ5 mpYUO  
// fileSplitterFetch[nPos.length-1].start(); K\2UwX  
;:/<XfZ  
!pMp n%r<]  
//等待子线程结束 k ='c*`IE  
//int count = 0; 2Kg+SLU[~  
//是否结束while循环 [!k#au+#c  
boolean breakWhile = false; 4-wCk=I  
l^$8;$Rq  
PI5a 'k0F  
while(!bStop) Y4 <  
{ XC D&Im  
write_nPos(); :{YOJDtR  
Utility.sleep(500); a1 I"Sh  
breakWhile = true; wACx}'+M  
av.L%l&d  
c@]_V  
for(int i=0;i<nStartPos.length;i++) sr*3uI-)L  
{ m/`"~@}&  
if(!fileSplitterFetch.bDownOver) Y9K$6lz  
{ -S7y1 )7  
breakWhile = false; NdlJdq  
break; F*bmV>Qq  
} :*`5|'G}  
} }z$_=v  
if(breakWhile) [It E+{U  
break; 1syI%I1  
:k"VR,riF  
3ZF-n`  
//count++; =WYI|3~Cz  
//if(count>4) *u|bmt  
// siteStop(); ?<l,a!V'6  
} z'(][SB  
J!5>8I(_wX  
)0Lno|l  
System.err.println("文件下载结束!"); ^Iz(V2  
} V\ 7O)g  
catch(Exception e){e.printStackTrace ();} C]xKdPQj%  
} ZMI!Sl  
9AxeA2/X  
KqE5{ q  
//获得文件长度 BJ]4j-^o  
public long getFileSize() :JEzfI1  
{ b&i0)/;  
int nFileLength = -1; BM@:=>ypQ  
try{ NFEF{|}BM  
URL url = new URL(siteInfoBean.getSSiteURL()); -S ASn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |K H&,  
httpConnection.setRequestProperty("User-Agent","NetFox"); is2OJ,  
n&51_.@Q  
JS&=V 67[  
int responseCode=httpConnection.getResponseCode(); _"Bh 3 7  
if(responseCode>=400) :ziV3jRM  
{ O=9mLI6  
processErrorCode(responseCode); =Z($n: m=*  
return -2; //-2 represent access is error + \DGS  
} CfSpwkg  
{5$.:Y  
U1Z.#ETnM  
String sHeader; RO]Vn]qb  
h]DS$WZ  
3%g\)Cs  
for(int i=1;;i++) R43yr+p  
{ ^hpdre"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ncGg@$E  
//Utility.log(in.readLine()); L*rND15  
sHeader=httpConnection.getHeaderFieldKey(i); *gJ:irah  
if(sHeader!=null) # -0}r  
{ 0&YW#L|J  
if(sHeader.equals("Content-Length")) ^Ia:e ?)W  
{ ~BS Ip .  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;~2RWj=-  
break; w=UFj  
} sn4wd:b7%  
} d^0vaX6e}  
else &<s[(w!%%  
break; x/UmpJD+  
} F@76V$U.  
} B ``)  
catch(IOException e){e.printStackTrace ();} :$>Co\D  
catch(Exception e){e.printStackTrace ();} .??[qBOTE  
K KPQ[3g  
!c;Z<@  
Utility.log(nFileLength); #LGAvFA*_F  
fO;#;p.  
7kQZ$sLc  
return nFileLength; Ic%c%U=i  
} 2=&4@c|cn  
 Stzv  
Z|8oD*,  
//保存下载信息(文件指针位置) P|>pm]>C  
private void write_nPos() 4H<@da}  
{ .ykCmznf*  
try{ vS!%!-F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7_HJ|QB  
output.writeInt(nStartPos.length); Y5 BWg  
for(int i=0;i<nStartPos.length;i++) gJkk0wok C  
{ W'>"E/Tx#O  
// output.writeLong(nPos); yJ\K\\]  
output.writeLong(fileSplitterFetch.nStartPos); *?'^R c  
output.writeLong(fileSplitterFetch.nEndPos); V<ZohB?y  
} K,!"5WrX*  
output.close(); W+F^(SC\  
} u9TiEEof3  
catch(IOException e){e.printStackTrace ();} 6 J&_H(^  
catch(Exception e){e.printStackTrace ();} ^""Ss  
} r+4<Lon~  
3kTOWIX  
HF2w?:  
//读取保存的下载信息(文件指针位置) vZDM}u  
private void read_nPos() <B }4}-}  
{ rF/k$_bFt  
try{ Rl. YF+YH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6AM-^S@  
int nCount = input.readInt(); =B0#z]qu  
nStartPos = new long[nCount]; Gu3# y"a>  
nEndPos = new long[nCount]; &YSjwRr  
for(int i=0;i<nStartPos.length;i++) (?G?9M#7_  
{ -3z$~ {  
nStartPos = input.readLong(); ,)S(SnCF  
nEndPos = input.readLong(); Kx-s95t  
} C EzTErn  
input.close(); #J=@} S)  
} 8PR1RC J  
catch(IOException e){e.printStackTrace ();} 7Fg-}lJAC  
catch(Exception e){e.printStackTrace ();} :o)4Y  
} l,I[r$TCf  
8&g`Uy/b  
lg9`Z>?  
private void processErrorCode(int nErrorCode) 9S .J%*F7  
{ ;tBc&LJ?  
System.err.println("Error Code : " + nErrorCode); j>OuNeo@4  
} i`FskEoijq  
4Ou|4WjnL  
0R#T3K}  
//停止文件下载 I;Sg 9`k=  
public void siteStop() pb\W7G  
{ >=T\=y  
bStop = true; &Z.zem?n  
for(int i=0;i<nStartPos.length;i++) l8$7N=Y  
fileSplitterFetch.splitterStop(); bv%A;  
%,Pwo{SH  
ySS kw7  
} "_g3{[es!  
} 9d\B*OU  
//负责部分文件的抓取 U2lDTRt  
**FileSplitterFetch.java Vb _W&Nwd  
*/ L.%N   
package NetFox; $aY*1UVq  
*/T.]^  
L\CufAN  
import java.io.*; myR}~Cj;q  
import java.net.*; K&\3j-8^  
=b{!p|  
W=[.. d  
public class FileSplitterFetch extends Thread { /C'dW  
e >OYJd0s  
z_A:MoYf o  
String sURL; //File URL g9rsw7  
long nStartPos; //File Snippet Start Position Po~u-5  
long nEndPos; //File Snippet End Position RPXkf71iM  
int nThreadID; //Thread's ID q h+c}"4m  
boolean bDownOver = false; //Downing is over gz,x6mnQ  
boolean bStop = false; //Stop identical ~> xVhd  
FileAccessI fileAccessI = null; //File Access interface =:4vRq [  
jkN-(v(T  
C6!P8qX  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -C>q,mDJZ  
{ }Q=@$YIesD  
this.sURL = sURL; MFHc>O DA  
this.nStartPos = nStart; SWrt4G  
this.nEndPos = nEnd; ,X&(BQj h  
nThreadID = id; .y)Y20=o!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 XDot3)2`  
} "!fvEE  
Qd{h3K^hlu  
TB8a#bK4  
public void run() Q9[$ 8  
{ bnm3 cR:h"  
while(nStartPos < nEndPos && !bStop) lrE|>R  
{ _YT9zG  
1]yjhw9g  
K4H U 9!  
try{ "F$0NYb]I  
URL url = new URL(sURL); WgV'T#*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ftw@nQNU  
httpConnection.setRequestProperty("User-Agent","NetFox"); #?V7kds]  
String sProperty = "bytes="+nStartPos+"-"; `H^?jX>7  
httpConnection.setRequestProperty("RANGE",sProperty); -kv'C6gB  
Utility.log(sProperty); Me.t_)  
Xv5|j/<~p  
T VuDK  
InputStream input = httpConnection.getInputStream(); x'uxSeH$  
//logResponseHead(httpConnection); M.[A%_|P  
r N.<S[  
P XH"%vVF  
byte[] b = new byte[1024]; MV~-']2u  
int nRead; ^EG@tB $<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7p!w(N?s  
{ I1TzPe  
nStartPos += fileAccessI.write(b,0,nRead); =` %iv|>r0  
//if(nThreadID == 1) _F"o0K!u  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'u%;5;%2  
} {e3XmVAI  
]t23qA@^2  
2&k5X-Y  
Utility.log("Thread " + nThreadID + " is over!"); ~I_v {  
bDownOver = true; _ i-(` 5  
//nPos = fileAccessI.write (b,0,nRead); IIrXI8'}  
} Z6`oGFq  
catch(Exception e){e.printStackTrace ();} n*HRGJ  
} .QaHE`e{  
} gk*Md+  
DH5]Kzb/  
jDaWmy<ha  
//打印回应的头信息 m V U(b,  
public void logResponseHead(HttpURLConnection con) W8/8V,  
{ jW?siQO^  
for(int i=1;;i++) L'*P;z7<  
{ l$:.bwXXO  
String header=con.getHeaderFieldKey(i); h /.^iT  
if(header!=null) B!#F!Wk"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); X`,]@c%C`  
Utility.log(header+" : "+con.getHeaderField(header)); !GNLq.rQ  
else neHozmm|  
break; ub#>kCL9  
} i l)LkZ@  
} .\W6XRw  
RgPY,\_9+  
Vd'KN2Jm  
public void splitterStop() _;M46o%h  
{ c<(LXf+61  
bStop = true; )/:r $n7  
} XHN`f#(w  
w(y#{!%+  
Ke_ & dgsq  
} |<YoH$.  
X~H ~k1  
77:s=)   
/* TC2gl[  
**FileAccess.java v7L} I[f  
*//文件访问(定位,写) K~?M?sa  
package NetFox; \w]c<gM K  
import java.io.*; 1o;*`  
c04"d"$ x  
<IX)D `mf  
public class FileAccessI implements Serializable{ *@C4~Zo  
!Gphs`YI  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 P@u&~RN9f+  
RandomAccessFile oSavedFile; Rilr)$  
long nPos; 9O%4x"*PO  
)ny,vcU]  
Rj/9\F3H  
public FileAccessI() throws IOException &SzLEbU!  
{ 5&uS700  
this("",0); C&\vVNV;9  
} D-/aS5wM  
OfR\8hAY  
""dX4^gtU  
public FileAccessI(String sName,long nPos) throws IOException PR&D67:Jy  
{ l<](8oc. w  
oSavedFile = new RandomAccessFile(sName,"rw"); R/yOy ^<  
this.nPos = nPos; CQq'x +{F  
oSavedFile.seek(nPos); Tz=YSQy$9  
} "/EE$eU  
s1[_Pk;!  
bEXm@-ou  
public synchronized int write(byte[] b,int nStart,int nLen) Wgh4DhAW  
{ 0P5!fXs*  
int n = -1; 9}4EW4  
try{ )6S;w7  
oSavedFile.write(b,nStart,nLen); `VT0wAe2;  
n = nLen; !`BK%m\8  
} pvz*(u  
catch(IOException e) yrDWIU(8;6  
{ yqg&dq  
e.printStackTrace (); [N|/d#  
} 5X7kZ!r  
5 i1T?  
! ~' \Ey  
return n; JJvf!]  
} s$ ONht  
/12D >OK  
I6]|dA3G  
} g5EdW=Dt,  
0d-w<lg9  
b}G4eXkuj  
/* 5-277?  
**SiteInfoBean.java seFug  
*/ 5(/ 5$u   
package NetFox; ;%1ob f 89  
[;c'o5M&  
a0"gt"q A  
public class SiteInfoBean { C?n3J  
1MtvnPY  
W#<&(s4  
private String sSiteURL; //Site's URL `ag7xd!  
private String sFilePath; //Saved File's Path $jYwV0  
private String sFileName; //Saved File's Name Y$^x.^dT,  
private int nSplitter; //Count of Splited Downloading File kT(}>=]g  
Nk-biD/J  
mx#H+:}&r  
public SiteInfoBean() qAH@)}  
{//nSplitter的缺省值为5 HQ%-e5Q  
//default value of nSplitter is 5 Z\=].[,w4  
this("","","",5); ~P*t_cpZ  
} lN,8(n?g  
E"Z9 NDgl#  
wHW";3w2~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {cF7h)j  
{ \?,'i/c-  
sSiteURL= sURL; \C3ir&  
sFilePath = sPath; ?VMj;+'tr  
sFileName = sName; U~8.uldnF  
this.nSplitter = nSpiltter; S9Fg0E+J  
v+Vpak9|  
[aF?1KxNMt  
} x@+m _y  
,L+tm>I  
]E66'  
public String getSSiteURL() 8Ek<J+& |I  
{ #e.2m5T  
return sSiteURL; Na^1dn  
} o~ .[sn5l-  
W{Cc wq  
Q dKxuG  
public void setSSiteURL(String value) k]<  
{ V1KWi ^  
sSiteURL = value; \s2hep  
} -ob_]CKtJ~  
ZdEeY|j  
a1p:~;f}[  
public String getSFilePath() DBl.bgf  
{ 0f vQPs!O  
return sFilePath; h<.G^c)  
} 'sJ=h0d_[V  
<^,w,A  
2}u hPW+  
public void setSFilePath(String value) y D.S"  
{ w,NK]<dU@  
sFilePath = value; bz_Zk  
} lgZ3=h  
)5lo^Qb  
B&0^3iKFi  
public String getSFileName() w:Fi 2aJ  
{ KQ3]'2q  
return sFileName; FxSBxz<N-A  
} (Q !4\Gy  
<@n/[ +3  
E|D~:M%~  
public void setSFileName(String value) *=L3bBu?  
{ E%\iNU!  
sFileName = value; 0SV#M6`GX  
} Wy%q9x]}  
QP|Ou*Qm)  
=+q9R`!L]  
public int getNSplitter() BVxg=7%St  
{ }cyHR1K  
return nSplitter; #Nxk3He]8  
} @FL?,_,Y{  
~=HN30  
w[z^B&  
public void setNSplitter(int nCount) !v|j C  
{ /-<S FT`  
nSplitter = nCount; ^_JD 7-g  
} ;Jt*s  
} d$s1l  
X 'Q$v~/  
\_FX}1Wc2.  
/* In|:6YDL&  
**Utility.java ~#iRh6 ^98  
*/ l?~SH[V  
package NetFox; D;)Tm|XizW  
^~(vP:  
K1Nhz'^=D  
public class Utility { eX 9{wb(  
T[s_w-<7$  
@(PYeXdV6&  
public Utility() ^jb55X}  
{ J_R54Y~vu  
$b\`N2J-_  
`CW8Wj  
} !<]%V]5[_  
ys:1%D,,_  
//线程睡眠 `pzp(\lc  
public static void sleep(int nSecond) e0"R7a  
{ tfj6#{M5  
try{ i$)bZr\  
Thread.sleep(nSecond); =,KRZqz  
}  ~%_$e/T  
catch(Exception e) h@FDP#H  
{ xh[Mmq/R  
e.printStackTrace (); HDYr?t~V  
} CfQOG7e@  
} 9H ?er_6Yf  
?hvPPEJf  
//日志 j$^3  
public static void log(String sMsg) K+xiov-r?  
{ a ^<W ?Z  
System.err.println(sMsg); #gi0FXL  
} -W wFUm  
< i*v  
O5{!CT$  
public static void log(int sMsg) p*F&G=ZE  
{ Adgh:'h  
System.err.println(sMsg); 33|>u+  
} OBi9aFoQ  
} _)Q) tOW  
ed4:r/Dpo  
MhNzmI&`  
/* %5RY Ea  
**TestMethod.java Bv \ihUg/  
*/ ,K .P,z~*  
package NetFox; xn1  
G!k&'{2  
vG O-a2Z  
public class TestMethod { Y8`4K*58%  
B:)9hF?o@  
-EFtk\/  
public TestMethod() 64>E|w  
{ ///xx/weblogic60b2_win.exe jDI O,XuF  
try{ |Y"q. n77  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7 }>j [  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :}TT1@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ej>8$^y  
fileFetch.start(); ]p:x,%nm  
} IBb3A  
catch(Exception e){e.printStackTrace ();} (%"M% Qko  
P0S ;aE  
UvRa7[<y%%  
} 7kO5hlKeo  
-}1S6dzr  
;$l!mv 7  
public static void main(String[] args) k'}}eu/ q  
{ sXOGIv  
new TestMethod(); 7g_:Gv~v  
} ?JDZDPVJ)  
} ct=|y(_  
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