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http断点续传简单实现(java)

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/* M0]l!x#7  
**SiteFileFetch.java 3gabk/  
*/ TJ; v}HSo  
package NetFox; =dA T^e##  
import java.io.*; (ZEVbAY?i  
import java.net.*; |%RFXkHS  
GU[ Cq=k  
`=KrV#/758  
public class SiteFileFetch extends Thread { zi-+@9T  
TS[Z<m  
b$$XriD]  
SiteInfoBean siteInfoBean = null; //文件信息Bean wd#AA#J;*  
long[] nStartPos; //开始位置 GrQl3 Xi  
long[] nEndPos; //结束位置 +] 5a(/m.~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _r8AO>  
long nFileLength; //文件长度 \clWrK  
boolean bFirst = true; //是否第一次取文件 E,6E-9  
boolean bStop = false; //停止标志 rk. UW  
File tmpFile; //文件下载的临时信息 \FKIEg+(2  
DataOutputStream output; //输出到文件的输出流 6op\g].P  
RDqC$Gu  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) /GeS(xzQ  
public SiteFileFetch(SiteInfoBean bean) throws IOException ZDDwh&h  
{ ,@!d%rL:4]  
siteInfoBean = bean; S~TJF}[k^6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); P)\f\yb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3\WES!  
if(tmpFile.exists ()) F 5JgR-P  
{ f:UN~z'yr  
bFirst = false; GecXMAa:2  
read_nPos(); ^Q OvK>W<  
} FN,uD:a  
else < Ihn1?  
{ <bjy<98LT  
nStartPos = new long[bean.getNSplitter()]; \)#3S $L~  
nEndPos = new long[bean.getNSplitter()]; Q` s(T  
} * ;M?R?+  
)xK!i.  
b,`\"'1  
VuBp$H(U  
}  mPD'"  
uf>w*[m5  
@'rO=(-b  
public void run() % (.PRRI  
{ ;C{_T:LS  
//获得文件长度 *AA1e}R{B  
//分割文件 #rC/y0niH  
//实例FileSplitterFetch \bsm#vY,  
//启动FileSplitterFetch线程 ibAA:I,d  
//等待子线程返回 gU%GM  
try{ 2?ednMoE  
if(bFirst) wS^-o  
{ v6n(<0:  
nFileLength = getFileSize(); T*ic?!  
if(nFileLength == -1) c"$_V[m  
{ -)Vj08aP  
System.err.println("File Length is not known!"); [< `+9R  
} Aa Ma9hvT!  
else if(nFileLength == -2) 0x & ^{P~  
{ K@,VR3y /  
System.err.println("File is not access!"); WE"'3u^k  
} ie ,{C  
else 950b9Vn&  
{ `^}9= Q'r  
for(int i=0;i<nStartPos.length;i++) B>mQ\Q  
{ !I Nr  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); pqr" x2=.  
} a&[nVu+  
for(int i=0;i<nEndPos.length-1;i++) BY d3rI  
{ ={Hbx> p  
nEndPos = nStartPos[i+1]; Sce9R?II  
} Zk[#B UA  
nEndPos[nEndPos.length-1] = nFileLength; o&O!Ur  
} `2oi~^.  
} `WT7w']NT  
i*tj@5MY-  
QM]^@2rK2  
//启动子线程 ^v'Lu!\f  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {8MF!CG]  
for(int i=0;i<nStartPos.length;i++) 9e5UTJ  
{ PA/6l"-`3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b1OB'P8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), YH>n{o;- ?  
nStartPos,nEndPos,i); tc',c},h~,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k);!H+  
fileSplitterFetch.start(); 3YRzBf:h  
} r__M1 !3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %Fv)$ :b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #?*jdN:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", d0^2<  
nEndPos = " + nFileLength); 'yNp J'  
// fileSplitterFetch[nPos.length-1].start(); GND[f}  
g;h&Xkp  
<gy'@w?  
//等待子线程结束 0d2%CsMS"D  
//int count = 0; t|m3b~Oyv  
//是否结束while循环 $3ILVT  
boolean breakWhile = false; 1:t>}[Y  
m+=!Z|K  
S`G\Cd;5  
while(!bStop) [ZbK)L+_  
{ &)l:m.  
write_nPos(); i&$uG[&P  
Utility.sleep(500); 7`}z7nk  
breakWhile = true; 2$91+N*w9  
1rEP)66N  
Xwi&uyvU&  
for(int i=0;i<nStartPos.length;i++) 9PAp*`J@kr  
{ UPYM~c+}  
if(!fileSplitterFetch.bDownOver) bq O"k t  
{ 1#(1Bs6X  
breakWhile = false; "J#:PfJ%  
break; -ZB"Yg$l  
} Exr7vL  
} 7E95"B&w  
if(breakWhile) R;o_*  
break; ||V:',#,W  
-eMRxa>  
qAS^5|(b[  
//count++; Nt8(  
//if(count>4) "x)DE,  
// siteStop(); [XXN0+ /  
} W<Lrfo&=Y]  
g$b*#  
.IXwa,  
System.err.println("文件下载结束!"); y#+o*(=fRE  
} 4_<Uk  
catch(Exception e){e.printStackTrace ();} * 5n:+Tw(  
} J%)2,szn0  
w%;'uN_  
5[_8N{QC;  
//获得文件长度 o1Ln7r.  
public long getFileSize() zTLn*?  
{ Sg-xm+iSDt  
int nFileLength = -1; |BW,pT  
try{ lND[anB!  
URL url = new URL(siteInfoBean.getSSiteURL()); 3p4?-Dd|_$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %j@FZ )a[  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^&iV%vQ[  
u*{ _WL[(  
.a*$WGb  
int responseCode=httpConnection.getResponseCode(); 1' m $_  
if(responseCode>=400) 9f\8oJQ  
{ ^v-'=1ub?  
processErrorCode(responseCode); 919g5f`  
return -2; //-2 represent access is error QGd- 9UEA]  
} p0K;m%  
 iC]lO  
w>u Z$/  
String sHeader; >{a,]q*  
p( *3U[1  
Q8?D}h  
for(int i=1;;i++) EcIQ20Z_-  
{ \]xYV}(FO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); W1 Qc1T8  
//Utility.log(in.readLine()); F/sBr7I  
sHeader=httpConnection.getHeaderFieldKey(i); mx~sxYa  
if(sHeader!=null) d&`j 8O  
{ jm\#($gl=  
if(sHeader.equals("Content-Length"))  #Uh 5tc  
{ "ux]kfoT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); AvZ) 1(  
break; Wg^cj:&`u  
} )/"7$2Aoy  
} &F_rg,q&_  
else 31& .Lnq  
break; u9w&q^0dqG  
} Kdu\`c-lB  
} 8F`  
catch(IOException e){e.printStackTrace ();} *K'ej4"u  
catch(Exception e){e.printStackTrace ();} P*`xiTA  
/Ph&:n\4  
.E#Sm?gK  
Utility.log(nFileLength); 5Q`n6x|  
(JW?azU  
-P>=WZu  
return nFileLength; :-La $I>  
} fhKiG%i'l  
.To:tN#  
<C;> $kX  
//保存下载信息(文件指针位置) sdYj'e:N  
private void write_nPos() e oSM@Isu  
{ |SKG4_wGe  
try{ SzX~;pFM0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); R Sz[6  
output.writeInt(nStartPos.length); t<F]%8S  
for(int i=0;i<nStartPos.length;i++) #J724`  
{ ^G&D4uZ  
// output.writeLong(nPos); ?K {1S  
output.writeLong(fileSplitterFetch.nStartPos); JZ/O0PW  
output.writeLong(fileSplitterFetch.nEndPos);  ii y3  
} Y>Hl0$:=  
output.close(); ><Z3<7K9  
} Fx5d@WNa>  
catch(IOException e){e.printStackTrace ();} 6L9[U^`@  
catch(Exception e){e.printStackTrace ();} d`uO7jlm  
} v9m;vWp  
+\GZ(!~  
lk1Gs{(qhH  
//读取保存的下载信息(文件指针位置) @B[Cc`IN"  
private void read_nPos() l/zC##1+.  
{ P<!$A  
try{ (%yc5+f!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !]+Z%ed`%  
int nCount = input.readInt(); 5!jNL~M  
nStartPos = new long[nCount]; > ' 0 ][~  
nEndPos = new long[nCount]; 6h6?BQSE  
for(int i=0;i<nStartPos.length;i++) wZ8 MhE  
{ kN |5 J  
nStartPos = input.readLong(); ]/Yy-T#@  
nEndPos = input.readLong(); dyiEK)$h  
} "C.7;Rvkp>  
input.close(); [Am`5&J  
} |( 9#vt#  
catch(IOException e){e.printStackTrace ();} [Cj)@OC  
catch(Exception e){e.printStackTrace ();} ?7MwTi8{F  
} tQ/ #t<4D  
HJaw\zbL  
kEhm'  
private void processErrorCode(int nErrorCode) ct4 [b|  
{ i4zV(  
System.err.println("Error Code : " + nErrorCode); }?]yxa~  
} [~c'|E8Q  
<o!&Kk9  
_b_?9b-)D  
//停止文件下载 ``|RO[+2  
public void siteStop() dM s||&|&  
{ {{ *]bGko  
bStop = true; AXP`,H  
for(int i=0;i<nStartPos.length;i++) 7X{bB  
fileSplitterFetch.splitterStop(); bLEATT[  
_gm?FxV:  
n<<=sj$\!  
} )w2K&Zr0  
} J4v0O="  
//负责部分文件的抓取 ct}%Mdg  
**FileSplitterFetch.java qJ+52U|z  
*/ (;pi"/x[  
package NetFox; M ?xpwqu\  
zf3:<CRX5  
Va@6=U7c  
import java.io.*; QhX C>)PW  
import java.net.*; H8$<HhuZM  
S1^nC tSF  
/ggkb8<3  
public class FileSplitterFetch extends Thread { Bug}^t{M  
YYE8/\+B.  
Z@,PZ   
String sURL; //File URL WVWS7N\  
long nStartPos; //File Snippet Start Position n(1wdlEp  
long nEndPos; //File Snippet End Position 3p3WDL7  
int nThreadID; //Thread's ID 6`qr:.  
boolean bDownOver = false; //Downing is over Q:kVCm/;  
boolean bStop = false; //Stop identical i&pJg1  
FileAccessI fileAccessI = null; //File Access interface 6b ]1d04hT  
ZEj!jWP2m  
/MKNv'5&!%  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _+\:OB[Y  
{ ,9Z2cgXwJ  
this.sURL = sURL; nx-1*  
this.nStartPos = nStart; O~h94 B`  
this.nEndPos = nEnd; (D>y6r> r  
nThreadID = id; XpgV09.EE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 | 7 m5P@X  
} dv'E:R(a  
=@JS88+  
n</k/Mk}  
public void run() qcTmsMpj  
{ c.(Ud`jc  
while(nStartPos < nEndPos && !bStop) ZD)0P=%  
{ 6Q2or n[  
,2,SG/BB  
XLZ j  
try{ F)/~p&H  
URL url = new URL(sURL); \f/#<|Hm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U=F-] lD  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4|6&59?pnc  
String sProperty = "bytes="+nStartPos+"-"; tE]5@b,R  
httpConnection.setRequestProperty("RANGE",sProperty); uNe}"hs  
Utility.log(sProperty); qDRNtFa  
-@ZzG uS(  
)X~Pr?52?  
InputStream input = httpConnection.getInputStream(); =a)iVXSB]  
//logResponseHead(httpConnection); Iz}2 ^  
G@!_ZM8h  
g\o{}Q%X  
byte[] b = new byte[1024]; .-SF$U_P*a  
int nRead; N7*CP|?E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]*2EK9<  
{ L\b]k,Ksf  
nStartPos += fileAccessI.write(b,0,nRead); _%wK}eH+sy  
//if(nThreadID == 1) -G],H)M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gX@nPZjg  
} psIkG0 &  
pbDw Lo]  
xH<'GB)  
Utility.log("Thread " + nThreadID + " is over!"); +{xMIl_  
bDownOver = true; G{kj}>kS_  
//nPos = fileAccessI.write (b,0,nRead); ^:4L6  
} (Sth:{;  
catch(Exception e){e.printStackTrace ();} uxa=KM1H  
} Q[J [=  
} _0,"vFdj  
\6 \hnP  
S3u yn78hI  
//打印回应的头信息 >|a\>UgC  
public void logResponseHead(HttpURLConnection con) 3ppuQ Q  
{  yS[z2:!  
for(int i=1;;i++) ;/@?6T"  
{ J3;Tm~KJ_  
String header=con.getHeaderFieldKey(i); h/I@_?k+  
if(header!=null) 3`58ah  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); uR#'lb`3  
Utility.log(header+" : "+con.getHeaderField(header)); IQ3n@  
else @Ex;9F,Q  
break; })@tA<+  
} n{dP@_>WS  
} >0PUWr$8  
f.| |PH  
LthGZ|>  
public void splitterStop() Dd| "iA  
{ +0]'| tF>  
bStop = true; g<fDY6jt  
} [ njx7d  
XtCoX\da  
%_R$K#T^,  
} *(k%MTG  
i"L }!5  
QU:EY'2  
/* pT4qPta,2  
**FileAccess.java Ptx,2e&Hq  
*//文件访问(定位,写) 1g1?zk8zO  
package NetFox; 4P|$LkI  
import java.io.*; G%a] j  
X Vw-G }5  
|~SE"  
public class FileAccessI implements Serializable{ %=V"CJ$|  
R N@^j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  bRNK.[|  
RandomAccessFile oSavedFile; @ ]f3| >I  
long nPos; DU;[btK>  
I*Vt,JYx  
%N )e91wC  
public FileAccessI() throws IOException VCjq3/[_  
{ cVp[ Z#B  
this("",0); *4t-e0]j@w  
} wW-Ab  
*=Doe2(!C  
 "Y7+{  
public FileAccessI(String sName,long nPos) throws IOException {AOG"T&<  
{ UP\C"\  
oSavedFile = new RandomAccessFile(sName,"rw"); OU!nN>ln  
this.nPos = nPos; f`9JE8  
oSavedFile.seek(nPos); ,j y<o+!  
} M;*$gV<x  
D?^540,b  
wa!zv^;N*  
public synchronized int write(byte[] b,int nStart,int nLen) P+h6!=nD7  
{ ^|#>zCt^  
int n = -1; S?L#N  
try{ Go1(@  
oSavedFile.write(b,nStart,nLen); eJ)1K  
n = nLen; 6 mCq/$  
} :G-1YA  
catch(IOException e) F;u7A]H^  
{ &y7 0  
e.printStackTrace (); L\YKdUL  
} G$C }?"l  
;7rd;zJ  
4QE=f(u;h  
return n; 7{pIPmJ  
} 7rcA[)<'  
Pp+~Cir  
f])M04<  
} NPm;  
9JPEj-3`g  
ocF>LR%P  
/* _.{zpF=j  
**SiteInfoBean.java `FZF2.N  
*/ %zzYleJ!]  
package NetFox; ca(U!T68  
 `?|Rc  
l-}KmZ]  
public class SiteInfoBean { +Q)ULnie e  
x? N.WABr;  
C/G]v*MBQ  
private String sSiteURL; //Site's URL aG(hs J)  
private String sFilePath; //Saved File's Path ZqQ*}l5  
private String sFileName; //Saved File's Name wK ?@.l)u  
private int nSplitter; //Count of Splited Downloading File 2ev*CX6.  
@4drjT  
Z\Z,,g+WL  
public SiteInfoBean() *YtB )6j  
{//nSplitter的缺省值为5 Q(Gyq:L=>  
//default value of nSplitter is 5 ([R")~`(l2  
this("","","",5); _({@B`N}  
} $W&:(&  
y<uAp  
X&a:g  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) M+poB+K.  
{ <~{du ?4n  
sSiteURL= sURL; *%\mZ,s"  
sFilePath = sPath; fW(/Loh  
sFileName = sName; *KJB>W%@uM  
this.nSplitter = nSpiltter; E9+HS  
sWHyL(C@  
Izn T|l^  
} ~~nqU pK?v  
JJ ?I>S N!  
F_=1;,K%  
public String getSSiteURL() I{ ryD -!  
{ 6Ps.E  
return sSiteURL; ?59'dGnz_  
} Zw{MgoJ0Z  
M0L&~p_F  
%2"J:0j  
public void setSSiteURL(String value) |sIr?RL{C  
{ c~imE%  
sSiteURL = value; ,%[4j9#!_  
} "R[l ZJ@  
pu9^e4B9  
7Xg?U'X  
public String getSFilePath() WC*=rWRxF  
{ ;3"@g]e  
return sFilePath; 6L9, 'Bg  
} q .J sf+  
m#e*c [*G  
V`#.7uUP  
public void setSFilePath(String value) C\}/"  
{ lpgd#vr  
sFilePath = value; y('k`>C  
} RWKH%C[Yd  
FhkkW W L  
3mO;JXd  
public String getSFileName() m$wlflt  
{ ]~0}=,H$N  
return sFileName; 5~'IKcW<  
} jlqv2V7=/  
/,s[#J   
}Fa%%}  
public void setSFileName(String value) J?&l*_m;t  
{ V'G Ju  
sFileName = value; CMW,slC_3  
} ,.tfWN%t\  
9Uf j  
+f|BiW  
public int getNSplitter() a.2L*>p  
{ ;H'gT+t<c  
return nSplitter; z6*<V5<7  
} 3j Z6kfj  
Y32 "N[yw  
R=]d%L8  
public void setNSplitter(int nCount) x Q4%e[/  
{ u92^(|  
nSplitter = nCount; y<:<$22O  
} z>m=h)9d~  
} P7.'kX9  
i-" p)2d=#  
*\G)z|^yx  
/* LWfqEL -  
**Utility.java ~" i0x  
*/ 1} %B%*N  
package NetFox; T{+Z(L  
B<?w h0  
3Ot~!AlR  
public class Utility { bBc[bc>R  
O+vS|  
;30nd=  
public Utility() XH}'w9VynR  
{ PG~$D];  
CW&.NT  
2`G OJ,$  
} eE GfM0  
vy9 w$ls  
//线程睡眠 jszK7$]^  
public static void sleep(int nSecond) -n80 &  
{ m908jI_So  
try{ v'!a\b`9  
Thread.sleep(nSecond); N$>^g"6 o  
} 'o_:^'c  
catch(Exception e) p5r]J+1  
{ 06q(aI^Ch@  
e.printStackTrace (); @#g<IBG=*  
} v59dh (:`Z  
} @.Ic z  
1KM`i  
//日志 ^(HUGl_  
public static void log(String sMsg) }7E^ZZ]f  
{ G` XC  
System.err.println(sMsg); o1cErI&q"  
} c2t=_aAIPQ  
j>-gO,v, y  
4%nE*H%  
public static void log(int sMsg) q@t0NvNSu  
{ )G^ KDj"  
System.err.println(sMsg); ="wzq+U  
} y*pUlts<  
} w-wV3Q6X  
:L44]K5FL  
ZOCDA2e(j  
/* li~d?>  
**TestMethod.java /DQaGq/Ld  
*/ /+Lfrt  
package NetFox; Qham^  
n!p<A.O7@  
+_XzmjnDd  
public class TestMethod { 6f')6X'x  
s<qe,' Y  
EkgE_8  
public TestMethod() -gSUjP  
{ ///xx/weblogic60b2_win.exe e/0<[s*#Q  
try{ 1$M@]7e+!+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); MrZh09y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <B9C*M"4%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Og,$ sH}`  
fileFetch.start();  J5^'HU3  
} oE#d,Z  
catch(Exception e){e.printStackTrace ();} 0 stc9_O  
ZovW0Q)m  
*h}XWBC1q  
} \"X!2  
E_vq  
]IoUwgpI)  
public static void main(String[] args) (p2K36,9m  
{ !%"8|)CAr  
new TestMethod(); j#cYS*^H  
} c-B cA  
} .zi_[  
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