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http断点续传简单实现(java)

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/* Y1)!lTG  
**SiteFileFetch.java x6W `hpL  
*/ o:~LF6A-  
package NetFox; bWmw3w  
import java.io.*; j/KO|iNL2  
import java.net.*; po7>IQS]  
* ?]~ #  
PX2c[CDE^  
public class SiteFileFetch extends Thread { ~e-z,:Af  
UG](go't  
u-3:k  
SiteInfoBean siteInfoBean = null; //文件信息Bean 5Sva}9H  
long[] nStartPos; //开始位置 36vgX=}  
long[] nEndPos; //结束位置 cj$d=k~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 nS9wb1Zl  
long nFileLength; //文件长度 _MuZ4tc  
boolean bFirst = true; //是否第一次取文件 02=lsV!U  
boolean bStop = false; //停止标志 r@kP*  
File tmpFile; //文件下载的临时信息 |ZiC`Nt  
DataOutputStream output; //输出到文件的输出流 %S \8.  
x`%JI=q  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) S\=1_LDx"  
public SiteFileFetch(SiteInfoBean bean) throws IOException -1u9t4+`  
{ oyvKa g  
siteInfoBean = bean; n}?wVfEy  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \)/yC74r7(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !5Sd2<N  
if(tmpFile.exists ()) y >+mc7n  
{ ?!'Zf Q:zK  
bFirst = false; iM]o"qOQm  
read_nPos(); !h`kX[:  
} KzV 2MO-$  
else *F`A S>  
{ "@/62b  
nStartPos = new long[bean.getNSplitter()]; hgj <>H|  
nEndPos = new long[bean.getNSplitter()]; 'xE _Cj  
} Fmr}o(q1  
yN6>VD{F  
 Vzl^Ka'  
VIJ<``9[  
} 8gy_Yj&{P  
gckI.[!b  
IzLQhDJ1  
public void run() X3%Ic`Lq#  
{ Ul+Mo&y-  
//获得文件长度 {d<;BLA  
//分割文件 F?-R$<Cn2~  
//实例FileSplitterFetch aZ|=(]  
//启动FileSplitterFetch线程 5ZY<JA3  
//等待子线程返回 ye}p~&  
try{ >e,mg8u6$  
if(bFirst) $I9qgDJ)  
{ &--ej|n  
nFileLength = getFileSize(); )#iq4@)|g  
if(nFileLength == -1) bm% $86  
{ }"^'% C8EX  
System.err.println("File Length is not known!"); 9DQa PA6  
} [7FItlF%I  
else if(nFileLength == -2) %w7pkh,  
{ |r%D\EB  
System.err.println("File is not access!"); OEx^3z^  
} hC <O`|lF  
else v <Kmq-b  
{ U}k9 Py  
for(int i=0;i<nStartPos.length;i++) E&$yuW^z  
{ Yz$3;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $%R$ G`.KM  
} &<RpWAk{  
for(int i=0;i<nEndPos.length-1;i++) ~m^ #FJu  
{ ^ vilgg~  
nEndPos = nStartPos[i+1];  rl2&^N  
} :GpDg  
nEndPos[nEndPos.length-1] = nFileLength; UMl#D >:C<  
} NKb1LbnZ*y  
} \*f;Xaa  
e [_m< e  
qMt++*Ls  
//启动子线程 E.|-?xQ6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; YH&bD16c3  
for(int i=0;i<nStartPos.length;i++) 9o*,P,j'}  
{ 6(d}W2GP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Rp7ntI:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), rE9I>|tX  
nStartPos,nEndPos,i); 5NoI~X=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /zDi9W*~1  
fileSplitterFetch.start(); }v:jncp  
} %wcSM~w  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :+Om]#`Vls  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :0 & X^]\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", k@ZLg9  
nEndPos = " + nFileLength); 2_vbT!_  
// fileSplitterFetch[nPos.length-1].start(); B33$pUk  
ABE@n%|`  
: G\<y  
//等待子线程结束 I$N8tn+E  
//int count = 0; t58e(dgi  
//是否结束while循环 )9l^O  
boolean breakWhile = false; !l]dR@e  
M" ^PW,k  
8#!i[UF dj  
while(!bStop) ; bHV  
{ Vq;dJ%sY  
write_nPos(); [(1c<b2r  
Utility.sleep(500); >h0-;  
breakWhile = true; dT,o=8fg  
otggN:^Qw  
[kE."#  
for(int i=0;i<nStartPos.length;i++) 7i&:DePM'q  
{ !,V{zTR  
if(!fileSplitterFetch.bDownOver) 5waKI?4F  
{ "HE^v_p  
breakWhile = false; \+aC"#+0  
break; 5onm]V]  
} 2^i(gaXUQ  
} g1t0l%_7^  
if(breakWhile) ,U(1NK8o  
break; i[wb0yL  
yR(x+ Gs{]  
o sKKt?^?  
//count++; a!O0,y  
//if(count>4) Q0EiEX)  
// siteStop(); ~ vqa7~}m  
} R<OI1,..r  
sc,Xw:YO  
o=0]el^A  
System.err.println("文件下载结束!"); =s<( P1|"  
} HRB<Y mP@  
catch(Exception e){e.printStackTrace ();} " Hd|7F'u=  
} Y nLErJ  
\hCH>*x<  
{%_L=2n6  
//获得文件长度 "etPT@gF  
public long getFileSize() j~*L~7  
{ W.kM7z>G  
int nFileLength = -1; 6{txm+U  
try{ itC-4^  
URL url = new URL(siteInfoBean.getSSiteURL()); )"pF R4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); uu`G 2[t  
httpConnection.setRequestProperty("User-Agent","NetFox"); S~|T4q(  
@')[FEdW  
9-MUX^?u  
int responseCode=httpConnection.getResponseCode(); 7hsGua  
if(responseCode>=400) jy'13G/b\  
{ z[Xd%mhjO  
processErrorCode(responseCode); P#AW\d^"B  
return -2; //-2 represent access is error TqnT S0fx  
} >y,-v:Vy  
%n*-VAfE\  
aA,!<^&}  
String sHeader; K.0:C`C  
Hw4%uS==V  
1YH+d0UGn  
for(int i=1;;i++) MG.` r{5  
{ Hro-d 1J7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Dd\jHF>u  
//Utility.log(in.readLine()); R rda# h^  
sHeader=httpConnection.getHeaderFieldKey(i); '*3h!lW1.  
if(sHeader!=null) ( SvWv m  
{ +llR204  
if(sHeader.equals("Content-Length")) AB4(+S*LA  
{ :8OZ#D_Hl  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M]J ^N#  
break; O&Y*pOg  
} pej|!oX  
} 4T ~}  
else 62zYRs\Y)X  
break; 9g mW&{6q  
} !_Wi!Vr_  
} &wV]"&-  
catch(IOException e){e.printStackTrace ();} K57&yVX  
catch(Exception e){e.printStackTrace ();} qw^uPs7Uw  
adR)Uq9  
3xaR@xjS  
Utility.log(nFileLength); cH&J{WeZa  
-[wGX}}  
w9bbMx  
return nFileLength; ;<ZLc TL  
} S Em Q@1  
| AozR ~  
N(Tz%o4  
//保存下载信息(文件指针位置) @"^0%/2-  
private void write_nPos() hbY5l}\5  
{ tIuCct-  
try{ .?loO3 m  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :s7m4!EF  
output.writeInt(nStartPos.length); \hx1o\  
for(int i=0;i<nStartPos.length;i++) &__es{;P  
{ r/u A.Aou^  
// output.writeLong(nPos); y#3j`. $3p  
output.writeLong(fileSplitterFetch.nStartPos); ?k(7 LX0j  
output.writeLong(fileSplitterFetch.nEndPos); ;;#qmGoE  
} )% ~OH  
output.close(); a m|F?|1  
} Tu).K.p:  
catch(IOException e){e.printStackTrace ();} AHXSt  
catch(Exception e){e.printStackTrace ();} LhA/xf  
} pu2 tY7J a  
)mF5Vw"  
@}}$zv6l,  
//读取保存的下载信息(文件指针位置) ;6>2"{NW  
private void read_nPos() ]7Tkkw$  
{ YTUZoW2  
try{ 7+\+DujE$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =4FXBPoQK  
int nCount = input.readInt(); ;wz^gdh;  
nStartPos = new long[nCount]; Utnr5^].2O  
nEndPos = new long[nCount]; WE:24b6  
for(int i=0;i<nStartPos.length;i++) d?A 0MKnl  
{ 8Dj c c z  
nStartPos = input.readLong(); *%%g{ 3$  
nEndPos = input.readLong(); VHIOwzC  
} 0Ziw_S\d&s  
input.close(); P\1L7%*lU  
} ;V*l.gr'2  
catch(IOException e){e.printStackTrace ();} a,k>Q`  
catch(Exception e){e.printStackTrace ();} i3 @)W4{  
} ~a ]+#D  
w9< R#y[A  
&L'Dqew,*  
private void processErrorCode(int nErrorCode) {xXsBh Y  
{ >n'o*gZM  
System.err.println("Error Code : " + nErrorCode); 1H6<[iHW  
} "@iK' c^  
:bwjJ}F  
y1dDO2mA  
//停止文件下载 n*[XR`r}  
public void siteStop() ;:\<gVi:  
{ L~lxXTG\  
bStop = true; >\KNM@'KI  
for(int i=0;i<nStartPos.length;i++) u{['<r;I  
fileSplitterFetch.splitterStop(); RI(DXWM|h  
9]f!'d!5  
tX_R_]v3  
} a7r%X -  
} D1zBsi94D  
//负责部分文件的抓取 p@xf^[50k  
**FileSplitterFetch.java _m5uDF?[  
*/ _Kl_61k  
package NetFox; Oo5w?+t  
`6~Aoe  
J^SdH&%Z  
import java.io.*; a_f~N1kq  
import java.net.*; cW@Zd5&0S  
+ElfZ4  
hT`J1nNt  
public class FileSplitterFetch extends Thread { O}-jCW;K  
zzTfYf)  
,(qRc(Ho  
String sURL; //File URL IzikDc10  
long nStartPos; //File Snippet Start Position )dbB =OZ  
long nEndPos; //File Snippet End Position a{^m-fSaR"  
int nThreadID; //Thread's ID gQWa24  
boolean bDownOver = false; //Downing is over hYPl&^  
boolean bStop = false; //Stop identical I*{4rDt  
FileAccessI fileAccessI = null; //File Access interface ,':fu  
 P5a4ze  
Mo?~_|}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException V58wU:li  
{ JTO~9>$ B  
this.sURL = sURL; de.&`lPRf  
this.nStartPos = nStart; nAW:utTB  
this.nEndPos = nEnd; A9I{2qW9+Z  
nThreadID = id; ($au:'kU  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Cl; oi}L  
} Rdvk ml@@  
DFZkh^PFd  
I`-8Air5f  
public void run() 5na~@-9p  
{ ;RDh ~EV  
while(nStartPos < nEndPos && !bStop) @XLy7_}  
{ n0r+A^]  
[Dk=? +  
q)X$^oE!6  
try{ OK[T3/v,  
URL url = new URL(sURL); Uzz'.K(Mv|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rI= v  
httpConnection.setRequestProperty("User-Agent","NetFox"); S%bCyK%p  
String sProperty = "bytes="+nStartPos+"-"; & ?h#Z!  
httpConnection.setRequestProperty("RANGE",sProperty); {MtpkUN  
Utility.log(sProperty); 1C}NQ!.  
.k,1f*%  
CtyoHvw+M  
InputStream input = httpConnection.getInputStream(); ciBP7>'::  
//logResponseHead(httpConnection); h`KFL/fT  
hn5h\M?  
Zn&, t &z  
byte[] b = new byte[1024]; Sg&UagBj  
int nRead; HePUWL'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %<k2#6K  
{ Gw>^[dmt!  
nStartPos += fileAccessI.write(b,0,nRead); FQu8 vwV6>  
//if(nThreadID == 1) d4u})  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t2/#&J]  
} lD)%s!  
#p P[xE"Y  
R)_%i<nq\  
Utility.log("Thread " + nThreadID + " is over!"); fol,xMc&  
bDownOver = true; PmkR3<=leg  
//nPos = fileAccessI.write (b,0,nRead); \Jx04[=  
} KK&rb~  
catch(Exception e){e.printStackTrace ();} Aw}"gpL  
}  CJ1 7n  
} G,?hp>lj  
QQ%D8$k"  
]RPs|R?  
//打印回应的头信息 10)jsA  
public void logResponseHead(HttpURLConnection con) Bp_$.!Qy  
{ }YB*]<]  
for(int i=1;;i++) :o|\"3  
{ \w/yF4,3<w  
String header=con.getHeaderFieldKey(i); `IP/d  
if(header!=null) $+P>~X)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VCY\be  
Utility.log(header+" : "+con.getHeaderField(header)); UJD 0K]s  
else [$qyF|/K`n  
break; Li!Vx1p;u.  
} )m`<H>[Eb=  
} Rn}l6kbM  
gp5_Z-me  
*,e:]!*  
public void splitterStop() ]JCvyz H  
{ zz+$=(T:M  
bStop = true; KC/=TSSXd.  
} -m)X]]~C  
kStnb?nk  
5Sm}n H  
} GR&z,  
.:@Ykdm4I  
fKeT,U`W  
/*  'C`U"I  
**FileAccess.java _7H7 dV  
*//文件访问(定位,写) !k 6K?xt  
package NetFox; DnC{YK  
import java.io.*; E)TN,@%  
6VS4y-N  
A0o-:n Fu  
public class FileAccessI implements Serializable{ LCZ\4g05  
&|Bc7+/P  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 FG%X~L<d,)  
RandomAccessFile oSavedFile; ?ATOXy  
long nPos; W}m)cn3@  
iL7DRQ1  
R9'b-5q  
public FileAccessI() throws IOException :yRo3c  
{ KV]X@7`@  
this("",0); &,}j #3<  
} JW{rA6?   
}T; P~aG  
Tu$f?  
public FileAccessI(String sName,long nPos) throws IOException WlB  
{ b<a4'M  
oSavedFile = new RandomAccessFile(sName,"rw"); rm5bkJcg~  
this.nPos = nPos; ~ DBcIy?  
oSavedFile.seek(nPos); \SN&G `o<  
} ZjgsR|i  
I%r{]-Obr-  
!F1M(zFD  
public synchronized int write(byte[] b,int nStart,int nLen) R@/"B8H  
{ 5 xppKt  
int n = -1; 6N",- c  
try{ 43|XSyS  
oSavedFile.write(b,nStart,nLen); 4[.oPK=i  
n = nLen; j"}*T  
} aNScF  
catch(IOException e) ZG>PQA  
{ V,mw[Hw  
e.printStackTrace (); }j^i}^Du,  
} IAw{P08+  
kddZZA3`  
^Y@\1fX 4e  
return n; '_GrD>P)-  
} xfpa]Z  
,5|&A  
**$LR<L  
} Gcdd3W`O  
"/3 db[  
v K9E   
/* ] Bcp;D  
**SiteInfoBean.java E;Y;z  
*/ )CuZDf@  
package NetFox; N):tOD@B  
 Of"  
P,xKZ{(  
public class SiteInfoBean { +_; l|uhT;  
-n=^U  
Ont%eC\  
private String sSiteURL; //Site's URL `}(b2Hc>  
private String sFilePath; //Saved File's Path Jz7!4mu  
private String sFileName; //Saved File's Name e8pG"`wM8  
private int nSplitter; //Count of Splited Downloading File i>D.!x  
qyF{f8pzq  
luo   
public SiteInfoBean() '^No)n\`  
{//nSplitter的缺省值为5 ]~aF2LJ_q  
//default value of nSplitter is 5 8vMG5#U[  
this("","","",5); -*$HddD  
} L\@I*QP  
G_0( |%  
n;@bLJ$W  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fDT%!  
{ W8ouO+wK  
sSiteURL= sURL; VKq=7^W  
sFilePath = sPath; :pGaFWkvO  
sFileName = sName; Ove<mFI\  
this.nSplitter = nSpiltter; l|/ep:x8  
P!H_1RwXKC  
.@(6Y<dN  
} vgsJeV`}I  
~F4fFQ-yy  
E~]R2!9  
public String getSSiteURL() 9f hsIe  
{ ;\]b T;#  
return sSiteURL;  f4Xk,1Is  
} ?AJKBW^  
7* yzEM  
*~t6(v?  
public void setSSiteURL(String value) v.pBX<  
{ tn Pv70m  
sSiteURL = value; j6Yy6X]  
} K POa|$  
yf[~Yl>Ogw  
-=~| ."O  
public String getSFilePath() _a6[{_Pc  
{ l038%U~U!  
return sFilePath; h|,:e;>}  
} 6LalW5I  
P(+&OoY2  
RloK,bg  
public void setSFilePath(String value) n?- })  
{ {so `/EWa  
sFilePath = value; [H6hyG~  
} 3BtaH#ZY  
bn!HUM,  
l|kSsP:GO  
public String getSFileName() H."EUcE{  
{ d-k%{eBV  
return sFileName; {]:7bV#JP  
} nEJY5Bz$  
KwPOO{4]g  
BW 4%l  
public void setSFileName(String value) 9{ >Ui  
{ .^h#_[dp  
sFileName = value; U56G.  
} G LIi6  
aqj@Cjk4Z  
gk"$,\DI  
public int getNSplitter() c_vqL$Dl  
{ cc~O&?)i  
return nSplitter; Qa-K$dm%  
} sj HrPs e  
I'uSp-Sfy  
mt,OniU=Q  
public void setNSplitter(int nCount) M<kj_.  
{ B56L1^ 7  
nSplitter = nCount; !,6c ~ w  
} ~N<4L>y<  
} z([ v%zf  
7f0lQ  
3'cE\u  
/* ]pH-2_  
**Utility.java %M7` Hwu  
*/ ;\14b?TUH  
package NetFox; 5N/%v&1  
u~WVGjoQ  
EfCx`3~EX  
public class Utility { Hn5|B 3vN  
@d mV  
Exc9` 7%.  
public Utility() va}Pj#=  
{ G!>z;5KuS  
e\!0<d  
t!r A%*  
} ihIVUu-M  
\=:~ki=@B  
//线程睡眠 )qo {c1X  
public static void sleep(int nSecond) d@XV:ae  
{ +n{#V;J  
try{ gcdlT7F)b-  
Thread.sleep(nSecond); CGY]r.O*  
} -f%'  
catch(Exception e) q*_/to  
{  %oZ6l*  
e.printStackTrace (); 925|bX6I  
} glM$R&/  
} 7UVzp v  
s$Z _48  
//日志 l49*<nkmq  
public static void log(String sMsg) .Le?T&_  
{ ]n_ k`  
System.err.println(sMsg); GO` Ru 8  
} $\]&rZVi  
]:4*L  
Ju96#v+:  
public static void log(int sMsg) ]rWgSID  
{ 8FKXSqhVM  
System.err.println(sMsg); zgNc4B  
} zNxW'?0Z?  
} c:<005\Bg  
kEOS{C%6R  
"B3N* R(["  
/* JBE!j-F  
**TestMethod.java M>~Drul  
*/ `$,GzS(  
package NetFox; Ta(Y:*Ri  
[d(U38BI  
nbm&wa[  
public class TestMethod { N G "C&v  
nqI@Y)  
&7PG.Ff!r  
public TestMethod() nExU#/*~^  
{ ///xx/weblogic60b2_win.exe wO'T BP  
try{ Fl kcU `j  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9 7GV2]-M  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >O*IQ[r-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); CE#gfP  
fileFetch.start(); jcuB  
} ^l9N48]|?  
catch(Exception e){e.printStackTrace ();} D8Ykg >B;&  
95 ;x=ju  
B@&4i?yJ  
} C G0 M  
DI:]GED" =  
NdMb)l)m  
public static void main(String[] args) nuk*.Su  
{ =Xi07_8Ic<  
new TestMethod(); 3Dng 1}  
} ABQ('#78  
} ';3{T:I  
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