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http断点续传简单实现(java)

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/* O^,%V{]6\  
**SiteFileFetch.java n6Qsug$z  
*/ #[C=LGi  
package NetFox; _rU%DL?  
import java.io.*; kg^VzNX  
import java.net.*; x<es1A'u6  
F+3}Gkn  
Lradyo44u\  
public class SiteFileFetch extends Thread { |kXx9vGq@  
c/Ykk7T9--  
2)zAX"#/  
SiteInfoBean siteInfoBean = null; //文件信息Bean -]K9sy)I  
long[] nStartPos; //开始位置 FELDz7DYya  
long[] nEndPos; //结束位置 Btgxzf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~l@ h  
long nFileLength; //文件长度 gL:Vj%c  
boolean bFirst = true; //是否第一次取文件 kED1s's  
boolean bStop = false; //停止标志 ^Voi 4;  
File tmpFile; //文件下载的临时信息 ~d072qUos  
DataOutputStream output; //输出到文件的输出流 BrO" _  
Dxlpo! ?#  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) :|tWKA  
public SiteFileFetch(SiteInfoBean bean) throws IOException j aEUz5  
{ @jxAU7!  
siteInfoBean = bean; ZcLW8L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WQ1~9#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); rV0X*[]J>  
if(tmpFile.exists ()) t/57LjV  
{ }pMd/|A,  
bFirst = false; [, )G\  
read_nPos(); V|n}v?f_q  
} |r%NMw #y  
else t0*,%ge:<  
{ Oe["4C  
nStartPos = new long[bean.getNSplitter()]; +-*Ww5Zti  
nEndPos = new long[bean.getNSplitter()]; Jb (CH4|7  
} >{HQ"{Q  
PV\aQO.mo  
UTLuzm  
5u89?-UD  
} #NZ#G~oeO  
^.|P&f~  
p?v.42R:z  
public void run() _P{f+HxU  
{ y k{8O.g  
//获得文件长度 f~0CpB*X  
//分割文件 # zbAA<f  
//实例FileSplitterFetch Ap<kK0#h  
//启动FileSplitterFetch线程 O8Dav^\y?  
//等待子线程返回 : [r/ Y  
try{ 9z$fDs}.q  
if(bFirst) Sr#\5UDS  
{ s1GR!*z>  
nFileLength = getFileSize(); N a $eeM  
if(nFileLength == -1) $"P[nNW3  
{ DQ*T2*L  
System.err.println("File Length is not known!"); nUy.gAb  
} o#~Lb9`@U  
else if(nFileLength == -2) fR$_=WWN>h  
{ ' %&gER  
System.err.println("File is not access!"); 9-3, DxZ}  
} . \t8s0A  
else EQTJ=\WFF  
{ 6^l|/\Y{  
for(int i=0;i<nStartPos.length;i++) w5+H9R6  
{ + ;LO|!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); lPyY  
} 5w+KIHhN|  
for(int i=0;i<nEndPos.length-1;i++) r&y0`M  
{ @/,:". SM  
nEndPos = nStartPos[i+1]; tSVWO] <  
} SYE+A`a  
nEndPos[nEndPos.length-1] = nFileLength; xk*&zAt  
} YLsOA`5X  
} ZO#f)>s2  
E#!tXO&,  
kfV}ta'^S  
//启动子线程 0Fw4}f.o  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5(=5GkE)>  
for(int i=0;i<nStartPos.length;i++) YWFq&II|Z  
{ 4^Y{ BS fF  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), omMOA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Cvp!(<<gK  
nStartPos,nEndPos,i); ZccvZl ;b  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9?XQB%44  
fileSplitterFetch.start(); 4=~+B z  
} n "bii7h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #PkZi(k hv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &"r /&7:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >I@VHl O  
nEndPos = " + nFileLength); ? Xl;>}zj  
// fileSplitterFetch[nPos.length-1].start(); gHo sPY[  
X`6"^ xme  
7 'q *(v  
//等待子线程结束 QdrZi.qKH  
//int count = 0; g7" 2}|qxo  
//是否结束while循环 (QTF+~)  
boolean breakWhile = false; x:K~?c3  
:N^+!,i  
y1)ZO_'  
while(!bStop) yT~rql  
{ -|GKtZ]}  
write_nPos(); uCr :+"C  
Utility.sleep(500); ?o6X_UxW!  
breakWhile = true; (Z0_e&=*  
^B)f!HtU  
QR2S67-  
for(int i=0;i<nStartPos.length;i++) ~].?8C.>*  
{ CkV5PU  
if(!fileSplitterFetch.bDownOver) Qhq' %LR  
{ w^"IR  
breakWhile = false; v YJ9G"E  
break; ;_=N YG.  
} PU,%Y_xR  
} UCt}\IJ  
if(breakWhile) /go|r '  
break; )qRH?Hsb7  
Vel}lQD  
%s! |,Cu  
//count++; H76iBJ66  
//if(count>4) s IFE:/1,  
// siteStop(); lrAhdi  
} -VeC X]  
xg}Q~,:  
bksv2@ar  
System.err.println("文件下载结束!"); ?I[*{}@n"  
} : eCeJ~&E  
catch(Exception e){e.printStackTrace ();} 3vs{*T"  
} 0|Xz-Y  
N=PSr4  
EE^x34&=  
//获得文件长度 kuI~lBWI  
public long getFileSize() `a%MD>R_Lg  
{ ?P}bl_  
int nFileLength = -1; " Lh&s<[  
try{ %.m+6 zaF  
URL url = new URL(siteInfoBean.getSSiteURL()); Xhq7)/jp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <iA\ZS:  
httpConnection.setRequestProperty("User-Agent","NetFox"); /5<=m:  
EV?U !O  
:KgH7s}  
int responseCode=httpConnection.getResponseCode(); sH.=Faos  
if(responseCode>=400) f S[-K?K  
{ &s(J:P$!  
processErrorCode(responseCode); =W &Mt  
return -2; //-2 represent access is error "M, 1ElQ  
} y^"@$   
p- a{6<h  
~o>Gm>5!HH  
String sHeader; Zwm/c]6`  
W#%s0EN<_  
f1]zsn:  
for(int i=1;;i++) _1NK9dp:  
{ EJ>&\Iq  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); a}uYv:  
//Utility.log(in.readLine()); |{&M#qXe  
sHeader=httpConnection.getHeaderFieldKey(i); {fnx=BaG  
if(sHeader!=null) 1X[^^p~^  
{ x9,jXd  
if(sHeader.equals("Content-Length")) n m<?oI*\  
{ {vGJ}q?Sd"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); s-_D,$ |  
break; j)2I+[aoB  
} <)p.GAZ  
} r=&,2meo  
else *68 TTBq(  
break; Z;%uDlcXI  
} p"#\E0GM  
} ~W[I  
catch(IOException e){e.printStackTrace ();} {G Jl<G1  
catch(Exception e){e.printStackTrace ();} ] \M+ju  
>UMxlvTg&  
c7jmzo  
Utility.log(nFileLength); {Q3OT  
~g\~x  
oX;.v9a  
return nFileLength; HJ]xZ83pC  
} R7/S SuG6\  
MzD1sWmK  
w.-x2Zg},  
//保存下载信息(文件指针位置) -BH/)$-$  
private void write_nPos() !1G KpL  
{ `UTPX'Vz  
try{ 8i154#l+\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -;7xUNQ  
output.writeInt(nStartPos.length); Zp> v  
for(int i=0;i<nStartPos.length;i++) 7a1o#O  
{ /[<F f  
// output.writeLong(nPos); >jX "  
output.writeLong(fileSplitterFetch.nStartPos); w6i2>nu_O  
output.writeLong(fileSplitterFetch.nEndPos); PjeI&@  
} oFj_o  
output.close(); #NW+t|E  
} 4<i#TCGex3  
catch(IOException e){e.printStackTrace ();} NX& dJ 6a  
catch(Exception e){e.printStackTrace ();} cuN9R G  
} HG;;M6  
kk /#&b2  
[kg?q5F)  
//读取保存的下载信息(文件指针位置) ENZym  
private void read_nPos() 2g= 6 s  
{ 1.du#w  
try{ SBreA-2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); N1Vj;-  
int nCount = input.readInt(); a;xeHbE  
nStartPos = new long[nCount]; $|=| "/  
nEndPos = new long[nCount]; ,Z~`aHhr  
for(int i=0;i<nStartPos.length;i++) 9^XZ|`  
{ ^I!Z)/  
nStartPos = input.readLong(); :}e<  
nEndPos = input.readLong(); |M;Nq@bRv  
} gw)4P tb!  
input.close(); ,D;8~l lM  
} \}$|Uo$O  
catch(IOException e){e.printStackTrace ();} dPEDsG0$a  
catch(Exception e){e.printStackTrace ();} ^3dc#5]Xf  
} I{89chi  
q`1tUd4G  
#kv9$  
private void processErrorCode(int nErrorCode) 8g0 #WV  
{ h-96 2(LG  
System.err.println("Error Code : " + nErrorCode); >%tP"x{  
} :^]Po$fl  
G<?RH"RZr  
v WXo#  
//停止文件下载 |HycBTN#E  
public void siteStop() 4;6"I2;zfG  
{ Fqeqn[,  
bStop = true; @&m [w'tn  
for(int i=0;i<nStartPos.length;i++) p%$r\G-x  
fileSplitterFetch.splitterStop(); N/o?\q8  
~EBaVl ({  
ec!e  
} }rJqMZ]w  
} ?ES{t4"  
//负责部分文件的抓取 I0F [Z\U  
**FileSplitterFetch.java 2E-Kz?,:[  
*/ w: BJ4bi=  
package NetFox; 'l/l]26rO4  
^VYR}1Mw  
gveGBi  
import java.io.*; Vx!ZF+  
import java.net.*; 12 )  
.u A O.<  
Kh3i.gm7g  
public class FileSplitterFetch extends Thread { \;-Yz  
;rf{T[i  
!\'w>y7  
String sURL; //File URL .Yk}iHcW.  
long nStartPos; //File Snippet Start Position !S<p"   
long nEndPos; //File Snippet End Position `m'RvUc  
int nThreadID; //Thread's ID W _[9  
boolean bDownOver = false; //Downing is over J)g +I  
boolean bStop = false; //Stop identical ~[!Tpq5  
FileAccessI fileAccessI = null; //File Access interface LiEEQ  
<RxxGD  
9+(b7L   
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %{ U (y#  
{ @^0}wk  
this.sURL = sURL; :LuA6  
this.nStartPos = nStart; &v]xYb)+<  
this.nEndPos = nEnd; F4=X(P_6  
nThreadID = id; /\fR6|tJ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C,ldi"|  
} 6Lq8#{/]u  
E7$ aT^  
LI-ewea  
public void run() WDnNVE  
{ k Jz^\Re  
while(nStartPos < nEndPos && !bStop) k7JC~D E#  
{ "S@]yL  
+ $M<ck?Bo  
XFFm 'W6@  
try{ +v%+E{F$+  
URL url = new URL(sURL); y@}WxSK*0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9|jMN j]vo  
httpConnection.setRequestProperty("User-Agent","NetFox"); yodhDSO5i  
String sProperty = "bytes="+nStartPos+"-"; UChLWf|'  
httpConnection.setRequestProperty("RANGE",sProperty); * r4FOA%P  
Utility.log(sProperty); >]B_+r0m^  
\`8$bpW[nS  
&|IO+'_  
InputStream input = httpConnection.getInputStream(); bz:En'2>F  
//logResponseHead(httpConnection); DFwiBB6  
r{~b4~kAf5  
pvWNiW:~k  
byte[] b = new byte[1024]; PYCG#U  
int nRead; 2n"-~'3\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dM"5obEb  
{ YxnZ0MY  
nStartPos += fileAccessI.write(b,0,nRead); J^WX^".E  
//if(nThreadID == 1) dRs\e(H'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); # - L<  
} 1< b~="  
mJ8EiRSE  
"SuG6!k3  
Utility.log("Thread " + nThreadID + " is over!"); #m{F*(%  
bDownOver = true; U*EBH  
//nPos = fileAccessI.write (b,0,nRead); !FK)iQy$0  
} ,A#gF_8  
catch(Exception e){e.printStackTrace ();} &/Gf@[  
} 9r:|u:i7m  
} 3W[||V[r]<  
\0*dKgN  
_+Z;pt$C  
//打印回应的头信息 HH3Z?g  
public void logResponseHead(HttpURLConnection con) ;<MHl[jJD  
{ 4<EC50@.  
for(int i=1;;i++) Ga^:y=m  
{ '0Q/oU  
String header=con.getHeaderFieldKey(i); ,-n_( U  
if(header!=null) &i805,lx  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <UIE-#  
Utility.log(header+" : "+con.getHeaderField(header)); >y!R}`&0^t  
else 'K23oQwDB  
break; k/U rz*O  
} xxgdp. (  
} N5MWMN[6aP  
2 9z@ !  
PTQN.[bBh  
public void splitterStop() =OrVaZ0  
{ DLq'V.M:  
bStop = true; .5~3D97X&  
} Eg4&D4TG p  
Q*f0YjH!  
Rto/-I0l  
} ~1Ffu x  
ZlMS=<hgFx  
6m:$RW  
/* p`"Ic2xPJ  
**FileAccess.java on7? V<  
*//文件访问(定位,写) l >oJ^J  
package NetFox; : t D`e<  
import java.io.*; ;Rxc(tR!n  
nWd;XR6|  
NwKj@Jos  
public class FileAccessI implements Serializable{ f(EO|d^u  
&j"_hFhv  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1O2V!?P  
RandomAccessFile oSavedFile; *mw *z|-^V  
long nPos; U @}r?!)"f  
|41~U\  
@E> rqI;`  
public FileAccessI() throws IOException }?CKE<#%  
{ ws;|fY  
this("",0); M>*xbBl  
} b-#oE{(\'  
$}H,g}@0  
msq2/sS~  
public FileAccessI(String sName,long nPos) throws IOException [.;I}  
{ 2p*!up(  
oSavedFile = new RandomAccessFile(sName,"rw"); ACEVd! q  
this.nPos = nPos; (F*y27_u  
oSavedFile.seek(nPos); tt&{f <*  
} <`BDN  
;6=*E'  
|/u,6`  
public synchronized int write(byte[] b,int nStart,int nLen) [t?:CgI)E  
{ pe!"!xJE  
int n = -1; R$2\Xl@qQF  
try{ i66/2BUh.  
oSavedFile.write(b,nStart,nLen); SO`b+B  
n = nLen; AgOti]`aR  
} C)cuy7<  
catch(IOException e) rj29$d?Y9  
{ 5',&8  
e.printStackTrace (); .07k G]  
} [KEw5-=i@  
;IT'6m`@W  
:?gp}.  
return n; t&o&gb  
} b:x~Jz#%2  
Rf!$n7& \  
 ,}^FV~  
} Rz<'& Z>;  
"!#KQ''R  
yi<H }&  
/* IRsyy\[kp8  
**SiteInfoBean.java m*14n_m'  
*/ o#-^Lg&  
package NetFox; ^HWa owy=  
RV@mAw.T  
NC"X{$o2  
public class SiteInfoBean { Dyj>dh-  
DNRWE1P2bg  
o}L\b,])  
private String sSiteURL; //Site's URL Vo(bro4ZQi  
private String sFilePath; //Saved File's Path 5QG?*Z~?7  
private String sFileName; //Saved File's Name %/r:iD  
private int nSplitter; //Count of Splited Downloading File wYd{X 8$  
yh+.Yn=+  
Y";K WA}b  
public SiteInfoBean() !!)NER-dv  
{//nSplitter的缺省值为5 r:t3Kf`+E-  
//default value of nSplitter is 5 > q8)~  
this("","","",5); |cl*wFm|3  
} r rs0|=  
dSE"G>l8  
/!pJ"@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2zkO s:  
{ m :2A[H+  
sSiteURL= sURL; 6&"GTK  
sFilePath = sPath; ( $,qxPOn  
sFileName = sName; -T>i5'2)  
this.nSplitter = nSpiltter; YN7JJJ/~T  
}k @S mO8  
E g_ram`\R  
} iE^=Vf;  
O0sLcuT$  
vSwRj<|CF  
public String getSSiteURL() (~?p`g+I.P  
{ "6i3'jc`  
return sSiteURL; n"Wlfd0  
} *~`BG5w  
Ed1y%mR>  
O_v*,L!  
public void setSSiteURL(String value) UYhxgPGsj  
{ 1P G"IaOb  
sSiteURL = value; SL`nt  
} Lv<vMIr  
C/q!!  
3]pHc)p!.  
public String getSFilePath() se29IhS!e  
{ rw[Ioyr-  
return sFilePath; pzeCdHF  
} JD]uDuE  
a" L9jrVrw  
`r&]Ydu:  
public void setSFilePath(String value) Q6xA@"GJ  
{ FQ u c}A  
sFilePath = value; M[QQi2:&  
} ]&X}C{v)G  
x !n8Wx  
k\-h-0[|  
public String getSFileName() HmbQL2  
{ $#E!/vVwD7  
return sFileName; N{uVh;_  
} plM:7#eA  
,OFNV|S$  
yV*4|EkvW  
public void setSFileName(String value) m"wP]OQH*+  
{ ^p3W}D  
sFileName = value; ]#vi/6\J  
} sEi9<$~R@0  
b8glZb*$  
gKtgW&PYm  
public int getNSplitter() =X7_!vSv  
{ $ByP 9=|  
return nSplitter; XJ7pX1nf  
} "6Z(0 iu:{  
\t)`Cp6,[b  
/ |isRh|  
public void setNSplitter(int nCount) \J(kM,ZJ  
{ 9T0g%&  
nSplitter = nCount; `yO'-(@"gY  
} #@F.wV0  
} &_74h);2I:  
~yJJ00%  
%Rk DR  
/* :TkMS8  
**Utility.java e9>~mtx  
*/ `UT UrM  
package NetFox; <(i5hmuVd  
^,aI2vC  
HEw&'  
public class Utility { W:K '2j  
I+ Y{_yw"f  
BAtjYPX'w  
public Utility() jwP5pu  
{ 3cF8DNh  
fElFyOo+  
nkf7Fq}  
} ?hViOh$.  
[v`kqL~  
//线程睡眠 :aH5=@[!y  
public static void sleep(int nSecond) gFsqCx<q  
{ Eihn%Esa  
try{ QQv%>=_`  
Thread.sleep(nSecond); <T&v\DN  
} '.&Y)A6!  
catch(Exception e) D}Sww5ZmP  
{ h`iOs>  
e.printStackTrace (); Hz)i.AA 4  
} u08QE,  
} QW tDZ>  
(e0(GOqf4  
//日志 KC)}M zt6_  
public static void log(String sMsg) r-.>3J  
{ 6@eF|GoP  
System.err.println(sMsg);  :>U+HQll  
} E;[Uhh|78!  
dT[JVl+3=  
'b y+hXk  
public static void log(int sMsg) 4u+0 )<  
{ uqLP$At  
System.err.println(sMsg); dCe LW  
} Nd&UWk^  
} XK})?LTD  
n>w<vM  
NpaS2q-d  
/* IdK<:)Q  
**TestMethod.java n2EPx(~  
*/ Qj*.Z4ue  
package NetFox; xF@&wg  
jFUpf.v2  
MpBdke$  
public class TestMethod { ~9E_L?TW*  
"%\hDL;  
@\o"zU  
public TestMethod() I2Imb9k~B  
{ ///xx/weblogic60b2_win.exe D <R_eK  
try{ G? XS-oSv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @5ud{"|2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Ri~$hs!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *0to,$ n  
fileFetch.start(); *@ H\J e`  
} .6xMLo,R  
catch(Exception e){e.printStackTrace ();} <fM}Kk  
qR_>41JU"  
@Z2np{X:  
} WTJ{M$  
o +7)cI  
x~vNUyEN)  
public static void main(String[] args) Fx|`0 LI+C  
{ _DH^ K 9,9  
new TestMethod(); ');vc~C  
} 0Q`v#$?":  
} U||GeEd  
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