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http断点续传简单实现(java)

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/* $22_>OsA  
**SiteFileFetch.java qY^@^)b[  
*/ ~0 5p+F)  
package NetFox; TcjTF|q>  
import java.io.*; Utv#E.VI  
import java.net.*; [>^xMF]$2  
%n7Y5|Uh  
3LK]VuZE  
public class SiteFileFetch extends Thread { sCi"qtHP  
y8k*{1MuO  
rr;p;  
SiteInfoBean siteInfoBean = null; //文件信息Bean 5OS|Vp||b  
long[] nStartPos; //开始位置 xQ{n|)i>  
long[] nEndPos; //结束位置 |y T-N3H@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 AXmW7/Sj"  
long nFileLength; //文件长度 C % d  
boolean bFirst = true; //是否第一次取文件 d \[cFe1d  
boolean bStop = false; //停止标志 H,I k&{@j  
File tmpFile; //文件下载的临时信息 F[HMX4  
DataOutputStream output; //输出到文件的输出流 rQ+2 -|#  
8;vpa*  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) }/cMG/%  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~l SdWUk>  
{ O wJZ?j& )  
siteInfoBean = bean; miCW(mbO8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wE*jN~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;3 |Z}P  
if(tmpFile.exists ()) G5K_e:i  
{ %n7mN])  
bFirst = false; )08mG_&atL  
read_nPos(); sb^%eUU])  
} SmR"gu  
else Y%"6  
{ 9 f+S-!  
nStartPos = new long[bean.getNSplitter()]; Ta 0Ln  
nEndPos = new long[bean.getNSplitter()]; ;WG6|QgV?-  
} H/Wo~$  
mxxuD"5  
2wKW17wj,  
=Y;w O8  
} &F xw19[G  
'c")]{  
iR`c/  
public void run() e.<y-b?  
{ d 6$,N|  
//获得文件长度 4Z"JC9As  
//分割文件 vi :IO  
//实例FileSplitterFetch V< ]l=JOd  
//启动FileSplitterFetch线程 _0uFe7sIZ  
//等待子线程返回 p~h)@  
try{ ={GYJ. *Ah  
if(bFirst) Pn;Tg7oz  
{ nWd]P\a'V  
nFileLength = getFileSize(); GNIZHyT(O  
if(nFileLength == -1) vXA+4 ?ZG  
{ 9N?BWv }  
System.err.println("File Length is not known!"); DQ a0S7I  
} eC71;"  
else if(nFileLength == -2) :^Ouv1!e1  
{ TAl#V 7PF}  
System.err.println("File is not access!"); E$w2S Q  
} 9iWs'M  
else k&kx%skz  
{ uk\-"dS  
for(int i=0;i<nStartPos.length;i++) Gx.iZOOH/  
{ 9sR?aW^$,/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); g/2eY$6Z  
} :Jz@`s1n  
for(int i=0;i<nEndPos.length-1;i++) AzwG_XgM)  
{ Sjogv  
nEndPos = nStartPos[i+1]; pP`KI'aUN  
} %I&[:  
nEndPos[nEndPos.length-1] = nFileLength; ;g M$%!&  
} BRu/pyxG  
} mF|7:zSo  
[`u3SN/P  
ELlTR/NW  
//启动子线程 GG KD8'j]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /J-:?./  
for(int i=0;i<nStartPos.length;i++) g'F{;Ur  
{ _Coh11  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T<\!7 RnLc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <o\2-fWvY  
nStartPos,nEndPos,i); aeP 6JHj  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Xw|t.0  
fileSplitterFetch.start(); ~gjREl,+D#  
} m3La;%aA0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T==(Pw7R7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); rTR4j>Ua~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ai 9UB=[R  
nEndPos = " + nFileLength); 6jGPmOM/  
// fileSplitterFetch[nPos.length-1].start(); %kcyE<c  
D)u 9Y  
>*5+{~k~4  
//等待子线程结束 RH+'"f  
//int count = 0; r-ldqj  
//是否结束while循环 /%fa_+,|-  
boolean breakWhile = false; 0%9Nf!j  
mM&*_#( 6  
_B5t)7I  
while(!bStop) x9c/;Q &m  
{ UX9r_U5)  
write_nPos(); $h({x~Oj9  
Utility.sleep(500); JpFfO<uO  
breakWhile = true; :-I~-Yj  
 3e<FlH{  
FzDZ<dJ  
for(int i=0;i<nStartPos.length;i++) |#r [{2sS  
{ 8, >YB+Hb  
if(!fileSplitterFetch.bDownOver) T vEN0RV2  
{ (Nky?*  
breakWhile = false; +&w=*IAKZ  
break; q $Hg\ {c  
} e2SU)Tr%b  
} |+^-b}0  
if(breakWhile) I^5T9}>Q  
break; ]G0`W6;$]  
YEEgDw]BQ  
 QTN _Z#'  
//count++; g' xR$6t  
//if(count>4) V ifQ@  
// siteStop(); /<HEcB  
} Y[A`r0  
=s2dD3Fr|  
t5%\`Yo?  
System.err.println("文件下载结束!"); HlkG^:)  
} :uAW  
catch(Exception e){e.printStackTrace ();} s[V$f vW  
} <By6%<JTn  
p8>.Q/4  
?a h<Qf]  
//获得文件长度 =ZsM[wd  
public long getFileSize() MZ(TST"  
{ q+MV@8w  
int nFileLength = -1;  M>mk=-l  
try{ v}=3  
URL url = new URL(siteInfoBean.getSSiteURL()); b9ON[qOMN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {\OIowa  
httpConnection.setRequestProperty("User-Agent","NetFox"); @$5GxIw<l  
e$k ]z HlQ  
>bf29tr  
int responseCode=httpConnection.getResponseCode(); 0L34)W  
if(responseCode>=400) -XVC,.Ly  
{ hSgfp  
processErrorCode(responseCode); ZWC-<QO"<  
return -2; //-2 represent access is error 6,"fH{Bd  
} }),tk?\  
AxaabS$\  
Pez 7HKW:  
String sHeader; T K)Kq  
iY=M67V  
lWv3c!E`  
for(int i=1;;i++) _]"5]c&*3  
{ 'L*nC T;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O IF0X!  
//Utility.log(in.readLine()); &&0,;r, -)  
sHeader=httpConnection.getHeaderFieldKey(i); |(gq:O  
if(sHeader!=null) Lx-ofN\  
{ Lp; {&=PIo  
if(sHeader.equals("Content-Length")) c2}?[\U]  
{ E^.y$d~dS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f`5e0;zm  
break; uzO%+B!  
} f\Bd lOJ>  
} }+[H~8)5  
else y.AF90Q>)  
break; UFxQ-GV4  
} m6a q_u{W  
} +\FTR  
catch(IOException e){e.printStackTrace ();} 5!ll #/ {`  
catch(Exception e){e.printStackTrace ();} /B$"fxFf  
D6iHkDTg  
ti:qOSIDTA  
Utility.log(nFileLength); 7$(>Z^ Em  
a!,q\p8<t0  
~q]+\qty4  
return nFileLength; mPNT*pAO  
} f>)k<-<yj  
r\y~ :  
%]JSDb=C  
//保存下载信息(文件指针位置) u>Z0ug6x  
private void write_nPos() Epm\ =s  
{ $oO9N^6yF  
try{ eRC /Pr  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .:tAZZ  
output.writeInt(nStartPos.length); )5Ddvz>+  
for(int i=0;i<nStartPos.length;i++) A KO#$OJE  
{ n*6b*fl  
// output.writeLong(nPos); \UI7H1XDH  
output.writeLong(fileSplitterFetch.nStartPos); ] X,C9  
output.writeLong(fileSplitterFetch.nEndPos); [&n2 yt  
} m~%\f8w-x  
output.close(); @O}%sjC1  
} ;z;O}<8s  
catch(IOException e){e.printStackTrace ();} i,R<`K0  
catch(Exception e){e.printStackTrace ();} Kk2PWJ7  
} X>w(^L*>  
L]L-000D(  
-LL49P6  
//读取保存的下载信息(文件指针位置) \|Pp%U [  
private void read_nPos() (W3~r  
{ jX^uNmb  
try{ 8kQ >M  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Vx@JP93|  
int nCount = input.readInt(); SI=vA\e  
nStartPos = new long[nCount]; Z~^)B8  
nEndPos = new long[nCount]; .g.v  
for(int i=0;i<nStartPos.length;i++) 'rJkxU{  
{ A4.Q \0  
nStartPos = input.readLong(); WJ$D]7  
nEndPos = input.readLong(); * B!uYP  
} YC#N],#  
input.close(); j  )6A  
} +E7s[9/r  
catch(IOException e){e.printStackTrace ();} -QL_a8NL  
catch(Exception e){e.printStackTrace ();} dzMlfJp  
}  4l+"J:,  
`_C4L=q"  
OD !b*Iy|  
private void processErrorCode(int nErrorCode) EnXNTat})  
{ !T/ ^zc;G  
System.err.println("Error Code : " + nErrorCode); {-IH?!&v  
} 5BCHW X*y  
Hc1S:RW  
:T(3!}4  
//停止文件下载 )J 4XM(  
public void siteStop() hjywYd]8  
{ DjK:)  
bStop = true; '#REbY5ev  
for(int i=0;i<nStartPos.length;i++) oJJ2y  
fileSplitterFetch.splitterStop(); 0R&$P 6  
b f.__3{  
5LU8QHj3  
} ; F% 3b47  
} ~aKxwH  
//负责部分文件的抓取 bD[W`yW0  
**FileSplitterFetch.java s^F6sXhyPi  
*/ W'w;cy:H  
package NetFox; BtS#I[-p_  
5q<AMg  
Lu!o!>b  
import java.io.*; X(Gp3lG  
import java.net.*; :,03)[u{8  
UN'[sHjOnD  
6('2.^8  
public class FileSplitterFetch extends Thread { ?zW4|0  
Vo^ i7  
_oK*1#Rm8  
String sURL; //File URL /?<o?IR~6  
long nStartPos; //File Snippet Start Position H'E(gc)>)  
long nEndPos; //File Snippet End Position $s-/![ 6  
int nThreadID; //Thread's ID VWqmqR%  
boolean bDownOver = false; //Downing is over .}Va~[0j  
boolean bStop = false; //Stop identical f0+)%gO{  
FileAccessI fileAccessI = null; //File Access interface &GF@9BXI3  
zi l^^wT0J  
;5qZQ8`4  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException oUrNz#U  
{ Vvk1 D(  
this.sURL = sURL; @&(0]kZ6  
this.nStartPos = nStart; {2Jo|z  
this.nEndPos = nEnd; rnW(<t"  
nThreadID = id; rM/Ona2x  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -0rc4<};h  
} +~b@W{  
qScc~i Oq  
9<BC6M_/  
public void run() X}*\/(fzl  
{ 8UiRirw  
while(nStartPos < nEndPos && !bStop) o NX-vN-  
{ 2fIHFo\8  
/<7'[x<  
?7>G\0G  
try{ KITC,@xE_O  
URL url = new URL(sURL); )Y.H*ca  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [w&B>z=g$  
httpConnection.setRequestProperty("User-Agent","NetFox"); .} al s  
String sProperty = "bytes="+nStartPos+"-"; +?r,Nn  
httpConnection.setRequestProperty("RANGE",sProperty); wWjZXsOd  
Utility.log(sProperty); #[$^M:X.  
5Fa.X|R~  
Fq\vFt|m<  
InputStream input = httpConnection.getInputStream(); S"+X+Oxp7?  
//logResponseHead(httpConnection); jroR 2*  
0;9X`z J  
5=Cea  
byte[] b = new byte[1024]; r]JV !'R  
int nRead; jpijnz{M  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @@->A9'L  
{ i+rh&,  
nStartPos += fileAccessI.write(b,0,nRead); ]\DZW4?'  
//if(nThreadID == 1) 4mYJi#e6x  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9Z, K  
} !R@v\Eu  
(55k70>i3  
G)~/$EF,_  
Utility.log("Thread " + nThreadID + " is over!"); 6! `^}4  
bDownOver = true; #Bu W  
//nPos = fileAccessI.write (b,0,nRead); h=:Ls]ZU  
} FfEP@$  
catch(Exception e){e.printStackTrace ();} o@T-kAEf-.  
} b ]A9$-  
} WBc,/lgZ  
ux>wa+XFa  
->"Z1  
//打印回应的头信息 `^_c&y K  
public void logResponseHead(HttpURLConnection con) 2z*EamF  
{ #6okd*^  
for(int i=1;;i++) f8ucJ.{"  
{ >#pZ`oPEAv  
String header=con.getHeaderFieldKey(i); '0ks`a4q  
if(header!=null) E~]37!,\\9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); oUSv)G.zb  
Utility.log(header+" : "+con.getHeaderField(header)); (r Tn6[ *  
else 3Lg)237&j  
break; vGX L'k  
} LR`]C]  
} *z?Vy<u G  
\tCxz(vKz  
U+[ p>iP  
public void splitterStop() Go;fQ yG  
{ GN0s`'#"3%  
bStop = true; 3.0t5F<B  
} pUV4oyGV   
Uw!N;QsC  
rJz`v/:|P  
} >]dH1@@  
P:8 qm DXo  
v?6g. [;?  
/* {wK| C<K  
**FileAccess.java czG]rl\1  
*//文件访问(定位,写) *3R3C+ L  
package NetFox; OV>JmYe1{/  
import java.io.*; ;*+wg5|  
5EX Ghc'  
.#Vup{.  
public class FileAccessI implements Serializable{ Al}D~6MD  
Sv#S_jh  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 b=$(`y  
RandomAccessFile oSavedFile; UiE 1TD{  
long nPos; Bjc<d,]  
Q0j4 c  
Y'&rSHI"  
public FileAccessI() throws IOException ,#V }qSKUS  
{ !pJd^|4A]  
this("",0); 4QZ|e{t  
} pB;8yz=  
59k[A~)~  
XbaUmCuh  
public FileAccessI(String sName,long nPos) throws IOException cqd}.D  
{ <>71;%e;'  
oSavedFile = new RandomAccessFile(sName,"rw"); +eUWf{(_  
this.nPos = nPos; Bx" eX>A8  
oSavedFile.seek(nPos); (qyT,K8  
} u%24% Q  
Rlwewxmr  
G2 {R5F !  
public synchronized int write(byte[] b,int nStart,int nLen) >{1 i8 b@  
{ SoJ=[5W  
int n = -1; (8Inf_59  
try{ &@U)  
oSavedFile.write(b,nStart,nLen); -]~KQvIH!  
n = nLen; *S= c0  
} -\I".8"YE  
catch(IOException e) 2~B9 (|  
{ ; 8B )J<y  
e.printStackTrace (); Oj]4jRew  
} ~TfN*0  
 8 ?4/  
-Cc2|~n  
return n; g3*J3I-O  
} bAwFC2jO[  
}trQ<*D  
 k:i}xKu  
} E``\Jre@  
w f""=;  
\ $Q?  
/* qBDhCE  
**SiteInfoBean.java .~Gt=F+`s  
*/ Vjqs\  
package NetFox; |T+YC[T#v  
CFW#+U#U  
~{00moN"m  
public class SiteInfoBean { d`sIgll&n  
kE[Hq-J=N  
AAc*\K  
private String sSiteURL; //Site's URL XCyAt;neon  
private String sFilePath; //Saved File's Path f+V^q4  
private String sFileName; //Saved File's Name /oC@:7  
private int nSplitter; //Count of Splited Downloading File P ~rTuj  
=u<jxV9  
q]rqFP0C  
public SiteInfoBean() e13' dCG  
{//nSplitter的缺省值为5 78h!D[6  
//default value of nSplitter is 5 %pUA$oUt  
this("","","",5); 4NDT5sL  
} Wagb|B\  
/I~(*X  
$,8}3R5}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J/>9w  
{ ["BD,mB  
sSiteURL= sURL; Xf%wW[~  
sFilePath = sPath; zL=PxFw0  
sFileName = sName; ,/Al'  
this.nSplitter = nSpiltter; s<'WTgy1i  
#McX  
'9tV-whw  
} XJ6=Hg4_O  
N?l  
b~Un=-@5a  
public String getSSiteURL() qk_YFR?R  
{ ['_W <  
return sSiteURL; (Y~gItej  
} FB }8  
8Y P7'Fz  
c +N\uG4  
public void setSSiteURL(String value) hOR1R B  
{ xY@<<  
sSiteURL = value; J|@kF!6  
} ftRzgW);  
s0/y> ok  
2B[I- K s  
public String getSFilePath() 'tJ@+(tqw  
{ vC%Hc/&.}  
return sFilePath; "7}e~*bM?`  
} I'c rH/z9  
bF c %  
fp2uk3Bm[  
public void setSFilePath(String value) WVdF/H  
{ [;$9s=:[  
sFilePath = value; (dHil#l  
} # 5b   
6g 5Lf)yG  
v{O(}@  
public String getSFileName() &H:2TL!  
{ k{E!X  
return sFileName; v O@7o  
} EeDK ^W8N  
gT#hF]c:  
_Eus7  
public void setSFileName(String value) xi}3)5  
{ NU(YllPB  
sFileName = value; d_)VeuE2  
} =@s{H +  
DpvMY94Qh  
%3es+A@  
public int getNSplitter() f <LRM  
{ aB2t/ua  
return nSplitter; g;\_MbfP  
} \!df)qdu  
Ak+MR EG  
g&fq)d  
public void setNSplitter(int nCount) <4RP:2#  
{ sG:tyvln  
nSplitter = nCount; A ^X1  
} Dz<vIMLF{  
} Q)93 +1]  
W3]?>sLE*  
N(Xg#m   
/* kA{eT  
**Utility.java E=RX^ 3+}  
*/ gi JjE  
package NetFox; j7 \y1$w  
nrJW.F]S8[  
P*3PDa@  
public class Utility { f;]C8/W  
j)Y68fKK  
^wMZG'/  
public Utility() x2Dg92  
{ 0jMS!"k   
zTW)SX_O  
Qkx}A7sK  
} MOIMW+n  
Vy@0Got5=  
//线程睡眠 W7?f_E\>W  
public static void sleep(int nSecond) I2e@_[ 1  
{ Km!~zG7<  
try{ NzG] nsw  
Thread.sleep(nSecond); *s6(1 S  
} rk< 3QXv  
catch(Exception e) P"<,@Mn  
{ Ag_I'   
e.printStackTrace (); DUWSY?^c  
} aSQvtv)91  
} hg+0!DVx  
OJXK]dZ  
//日志 \>)#cEX5  
public static void log(String sMsg) /YD2F  
{ #GIjU1-  
System.err.println(sMsg); LseS8F/q  
} ]C5/-J,F  
O"m(C[+ [  
LNI]IITx/  
public static void log(int sMsg) lJdwbuB6  
{ ^u$?& #  
System.err.println(sMsg); 1wt(pkNk  
} >f-*D25f%  
} 7|^5E*8/  
1Gh3o}z  
f/tJ>^N5  
/* J:G~9~V^  
**TestMethod.java "cx#6Bo|  
*/  :qrCqFl  
package NetFox; r"x/,!_E  
on)$y&lu  
UCI !>G  
public class TestMethod { \@F!h8e4  
9q>rUoK^  
@%4tWE  
public TestMethod() i3U_G^8  
{ ///xx/weblogic60b2_win.exe Ztj~Q9mu  
try{ Z=[?T f  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xOBzT&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TY]-L1$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ),&tF_z:  
fileFetch.start(); 0/,Dy2h  
} +hz S'z)n&  
catch(Exception e){e.printStackTrace ();} %TS8 9/  
*."a>?D~  
Erq% Ck(  
} *;Gnod<  
d <Rv~F@  
GOj<>h}r  
public static void main(String[] args) ?@5#p*u0  
{ \@hq7:Q  
new TestMethod(); X'.*I])  
} *k<{nj@y  
} GcCMCR3  
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