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http断点续传简单实现(java)

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/* J<Di2b+  
**SiteFileFetch.java @0A7d $J(  
*/ @mBZu!,  
package NetFox; laN:H mR8  
import java.io.*; 7UvfXzDNC  
import java.net.*; PeGL Rbx34  
)K.~A&y@  
@.ebQR-:H  
public class SiteFileFetch extends Thread { v'0A$`w`  
DK 4 8  
z><=F,W  
SiteInfoBean siteInfoBean = null; //文件信息Bean K.c6n,'  
long[] nStartPos; //开始位置 o5KpiibFM  
long[] nEndPos; //结束位置 XL>v$7`#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x'_I{$C &  
long nFileLength; //文件长度 %[0V>  
boolean bFirst = true; //是否第一次取文件 :iJ+ImBpK  
boolean bStop = false; //停止标志 =jIB5".  
File tmpFile; //文件下载的临时信息 T X.YTU  
DataOutputStream output; //输出到文件的输出流 _cdrz)T  
+@[T0cXp  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ScU?T<u:i  
public SiteFileFetch(SiteInfoBean bean) throws IOException W|J8QNL?jm  
{ ?{l}35Q.@  
siteInfoBean = bean;  {h/[!I `  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U8L%=/N>B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); DJ;il)^  
if(tmpFile.exists ()) x>vC;E${"  
{ 8 hx4N  
bFirst = false; J'9hzag  
read_nPos(); g*69TqO^  
} DdDO.@-Z  
else j:K>3?   
{ eAN]*: ]g  
nStartPos = new long[bean.getNSplitter()]; s^+h>  
nEndPos = new long[bean.getNSplitter()]; P F#+G;q;  
} Cm g(# $ X  
asqbLtQ  
lPyGL-Q  
.&dW?HS  
} c?B@XIl  
f tW-  
)8]O|Z-CU  
public void run() ]vRte!QJ;  
{ d2sY.L  
//获得文件长度 JVbR5"+.  
//分割文件 s<VNW  
//实例FileSplitterFetch @NlE2s6a  
//启动FileSplitterFetch线程 `Yn:fL7S  
//等待子线程返回 m` ^o<V&  
try{ (UWWULV  
if(bFirst) 9qS~-'&q#  
{ }&A!h  
nFileLength = getFileSize(); $5kb3x<W  
if(nFileLength == -1) DXu915  
{ FrBoE#  
System.err.println("File Length is not known!"); 6lw)L  
} Q qGf*  
else if(nFileLength == -2) .%;`: dtj  
{ - ;1'{v  
System.err.println("File is not access!"); ?145^ w  
} ;sd[Q01  
else 3D L7  
{ vAWJP_;J  
for(int i=0;i<nStartPos.length;i++) Bfe#,  
{ F N6 GV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,:POo^!/fT  
} uFQ;}k;}  
for(int i=0;i<nEndPos.length-1;i++) vYQ0e:P  
{ $SAq/VHI1]  
nEndPos = nStartPos[i+1]; Nn<TPT[,  
} wdg,dk9e$  
nEndPos[nEndPos.length-1] = nFileLength; =K'X:UM  
} AjBwj5K  
} _N!L?b83P  
2"+8NfFl  
yh0zW $  
//启动子线程  *R1 m=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; IcmTF #{D  
for(int i=0;i<nStartPos.length;i++) AyHhq8Y  
{ eV:I :::  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A|>~/OW=@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gDbj!(tm  
nStartPos,nEndPos,i); dsck:e5agZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V4I5PPz~  
fileSplitterFetch.start(); 02B *cz_K  
} D2N| A  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K8[vJ7(!|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Y,BzBUWK  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", M)4-eo  
nEndPos = " + nFileLength); ~q]@Jp  
// fileSplitterFetch[nPos.length-1].start(); _9yb5_  
 v?Dc3  
FYPv:k   
//等待子线程结束 dr3j<D-Q  
//int count = 0; x(oL\I_Z  
//是否结束while循环 to9~l"n.s  
boolean breakWhile = false; !p$HS0c  
P^9y0Q  
}-YM>q  
while(!bStop) JSz;>  
{ pG"pvfEl9f  
write_nPos(); ptJ58U$Bb  
Utility.sleep(500); f_A'.oq+  
breakWhile = true; }AfX0[!O  
qw^kA?  
cGF_|1`  
for(int i=0;i<nStartPos.length;i++) 7#/->Y  
{ a#3+PB #  
if(!fileSplitterFetch.bDownOver) Ws;S=|9,7~  
{ ='r86vq  
breakWhile = false; Ff6l"A5  
break; +/xmxh$ $  
} l~ 3H"  
} )~W 35  
if(breakWhile) ^`M,ju  
break; SURbH;[   
9*s''=  
u|]{|Ya'%  
//count++; 6/{V#.(  
//if(count>4) wf*G+&b d2  
// siteStop(); {qxFRi#\k  
} WX.6|  
QuFzj`(  
akR+QZ,)  
System.err.println("文件下载结束!"); ])`+ 78  
} x=-dv8N?  
catch(Exception e){e.printStackTrace ();} RRSkXDU}  
} >ZRCM  
{#?$ p i[  
>O0z+tj  
//获得文件长度 J)R2O{z  
public long getFileSize() _(A9k{  
{ $z1W0  
int nFileLength = -1; sKE7U>mz|  
try{ GJTKqr|1O  
URL url = new URL(siteInfoBean.getSSiteURL()); (]c M ;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VtM:~|v  
httpConnection.setRequestProperty("User-Agent","NetFox"); )|52B;yZx  
GFA D  
W^U6O&-K  
int responseCode=httpConnection.getResponseCode(); kdmmfw  
if(responseCode>=400) :Q\Es:y  
{ UXs=7H".  
processErrorCode(responseCode); Cn\5Vyrl  
return -2; //-2 represent access is error h>0R!Rl8  
} op!ft/Yyb  
:vsBobiJ  
|:qaF  
String sHeader; Tt^PiaS!  
/NE<?t N  
gc5u@(P"  
for(int i=1;;i++) ;Gf,I1d}{  
{ <V`1?9c7D1  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); sY|by\-c  
//Utility.log(in.readLine()); |4E5x9J  
sHeader=httpConnection.getHeaderFieldKey(i); WA'4y\N  
if(sHeader!=null) UQ X.  
{ *yx5G-#?  
if(sHeader.equals("Content-Length")) YJ6y]r K2,  
{ v3zd>fDnRp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Z~X\Z.  
break; v w.rkAGY  
} oc|%|pmRd<  
} .$o0$`}  
else %R?B=W7 ;Q  
break; K[,d9j`^  
} *s=jKV#  
} +, IMN)?;z  
catch(IOException e){e.printStackTrace ();} eT!*_.' e  
catch(Exception e){e.printStackTrace ();} v d{`*|x  
a9f!f %9  
f0^;*Y  
Utility.log(nFileLength); {pWb*~!k  
0\B31=N(  
# 1,"^k^  
return nFileLength; 0c-.h  
} A'zXbp:%  
?'xwr )v  
(u_?#PjX  
//保存下载信息(文件指针位置) XJ$mRh0`K  
private void write_nPos() bU3P; a(  
{ )2pOCAjL2  
try{ "r+v^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); G5l?c@o  
output.writeInt(nStartPos.length); uGoySt&;(  
for(int i=0;i<nStartPos.length;i++) !^Ly#$-X  
{ 6@rebe!&=  
// output.writeLong(nPos); YK{E=<:  
output.writeLong(fileSplitterFetch.nStartPos); l-v(~u7  
output.writeLong(fileSplitterFetch.nEndPos); (GCeD-  
} e> zv+9'Q  
output.close(); eb ` !  
} Rfx}[!<{N  
catch(IOException e){e.printStackTrace ();} c>$PLO^  
catch(Exception e){e.printStackTrace ();} n%Rl$  
} $~;h}I  
-J6G=+ s/  
K|Cb6''  
//读取保存的下载信息(文件指针位置) `SfBT1#5G  
private void read_nPos() ;h"St0   
{ B=<Z@u  
try{ DN X-\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); [^D~T  
int nCount = input.readInt(); #F^0uUjq  
nStartPos = new long[nCount]; ~K 2.T7=  
nEndPos = new long[nCount]; m)1+D"z  
for(int i=0;i<nStartPos.length;i++) f{HjM? Mb3  
{ S - N [  
nStartPos = input.readLong(); Y[R;UJE`5  
nEndPos = input.readLong(); F ]x2;N  
} 5R%4fzr&g  
input.close(); `;c{E%qeq  
} n OQvBc  
catch(IOException e){e.printStackTrace ();} Cu $mb}@  
catch(Exception e){e.printStackTrace ();} [6u8EP0xM  
} \RF{ITV$kD  
e[($rsx  
|19zjhl  
private void processErrorCode(int nErrorCode) r7zS4;b  
{ S|Yz5)*  
System.err.println("Error Code : " + nErrorCode); HZl//Uq  
} 'V`Hp$r  
bd;?oYV~  
n85d g  
//停止文件下载 K\VL[HP-  
public void siteStop() %+bw2;a6  
{ Uaz$<K6  
bStop = true; g;eoH  
for(int i=0;i<nStartPos.length;i++) %2ZWSQD  
fileSplitterFetch.splitterStop(); YVW`|'7)|  
9`FPV`/  
-L6V)aK&  
} 50R&;+b  
} K9=f`JI9  
//负责部分文件的抓取 #\T5r*W  
**FileSplitterFetch.java + d289"  
*/ rk)h_zN  
package NetFox; 2_C&p6VGj  
G9AQIU%ii  
Mrly(*!U"@  
import java.io.*; ><DXT nt'x  
import java.net.*; !)//b]  
wqE+hKs,  
zy\R>4i'#Q  
public class FileSplitterFetch extends Thread { slH3c:j\  
)+dd  
egn9O  
String sURL; //File URL +2 x|j>  
long nStartPos; //File Snippet Start Position S7kZpD $  
long nEndPos; //File Snippet End Position iji2gWV}h  
int nThreadID; //Thread's ID =LyR CrA  
boolean bDownOver = false; //Downing is over uD8,E!\  
boolean bStop = false; //Stop identical .[:2M9Rx  
FileAccessI fileAccessI = null; //File Access interface ;vp[J&=  
_@A%t&l  
+<$b6^>!$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Jj'dg6QY'  
{ vcz?;lg  
this.sURL = sURL; )ad6>Y  
this.nStartPos = nStart; b Sm*/Q  
this.nEndPos = nEnd; =&x u"V  
nThreadID = id; 3x3 =ke!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "jA?s9  
} QQW]j;'~  
*'\ xlsp#  
o?((FW5.;  
public void run() up )JU [  
{ ;Sw % t(@  
while(nStartPos < nEndPos && !bStop) ]`T*}$|  
{ v7#`b}'W  
N*6lyFcg  
WX}pBmU  
try{ R|JBzdK+P  
URL url = new URL(sURL); P{[@t_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6[S-%|f  
httpConnection.setRequestProperty("User-Agent","NetFox"); !UF (R^  
String sProperty = "bytes="+nStartPos+"-"; &A)u!l Ue  
httpConnection.setRequestProperty("RANGE",sProperty); ]h 4r@L3  
Utility.log(sProperty);  c FV3  
wpV)y Q^  
QvvH/u  
InputStream input = httpConnection.getInputStream(); p{W'[A{J .  
//logResponseHead(httpConnection); [*W l=  
#8sv*8&  
6< @F  
byte[] b = new byte[1024]; Q%.F Mf  
int nRead; df@G+v0_1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) I6.}r2?;A  
{ DWmViuZmL  
nStartPos += fileAccessI.write(b,0,nRead); hVf;{p &  
//if(nThreadID == 1) u~\l~v^mj  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {"n=t`E)3  
} x) OJ?l  
4>}qdR1L4  
R~!md  
Utility.log("Thread " + nThreadID + " is over!"); &8M^E/#.^;  
bDownOver = true; ! w2BD^V-  
//nPos = fileAccessI.write (b,0,nRead); &p_V<\(%  
} 1vUW$)?X  
catch(Exception e){e.printStackTrace ();} %mr6p}E|  
} (hn;C>B  
} i;I!Jc_b'  
L6n<h  
mz?1J4rt  
//打印回应的头信息 *7UDTgY  
public void logResponseHead(HttpURLConnection con) O#3PUuE%d  
{ +xn59V  
for(int i=1;;i++) WR5W0!'Tf  
{ tr-muhuK  
String header=con.getHeaderFieldKey(i); $Fik]TbQp  
if(header!=null) 1YJ@9*l  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y7WU4He L  
Utility.log(header+" : "+con.getHeaderField(header)); = @n`5g  
else rO7[{<97m  
break; kJK:1;CM?.  
} <nbc RO.  
} E=L 1q)  
|jJ9dTD8/  
WN3]xw3  
public void splitterStop() ,@r 0-gL  
{ yYn7y1B  
bStop = true; 9KDm<Q-mf  
} K} TSwY  
xay~fD  
-,^Z5N#\|  
} -cL wjI  
Tv /?-`Y  
`| f1^C^  
/* 6<m9guv  
**FileAccess.java ql(~3/kA_  
*//文件访问(定位,写) >@?`n}r|  
package NetFox; <-O^ol,fX  
import java.io.*; bPUldkB:  
;QqC c!b  
NNn sq@?6  
public class FileAccessI implements Serializable{ 8 GW0w  
#v}pn2g%>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Cm~z0c|T  
RandomAccessFile oSavedFile; zx`(ojfu  
long nPos; dj5@9X  
f2G 3cg~H  
3fdqFJ O  
public FileAccessI() throws IOException H.#zbKj  
{ 7p[NuU*Gg  
this("",0); cs7K^D;.V  
} 3eR c>^wh  
` 3h,Cy^  
[J +5  
public FileAccessI(String sName,long nPos) throws IOException E5 uk<e_  
{ (65|QA   
oSavedFile = new RandomAccessFile(sName,"rw"); gaU1A"S}  
this.nPos = nPos; Q 1[E iM3  
oSavedFile.seek(nPos); 8&c:73=?X  
} eoxEnCU  
Z:.*fs5  
3B?7h/f  
public synchronized int write(byte[] b,int nStart,int nLen) e1Bqd+  
{ kadw1sYj  
int n = -1; bEli!N$  
try{ zCI.^^<?  
oSavedFile.write(b,nStart,nLen); "P8( R  
n = nLen; g![?P"i^t  
} m\@q2l-  
catch(IOException e) h1Logm+m  
{ w<Ot0&&  
e.printStackTrace (); R/Te ;z  
} ?$~5ti#\  
DH!_UV  
A0 $ds  
return n; J8?V1Ad{  
} a}V<CBi  
/kNSB;  
yt#~n _  
} UNyk, #4  
BoP,MpF  
F&$~]R=&  
/* <~n%=^knE  
**SiteInfoBean.java 2k+u_tj>  
*/ v%;Ny ab6$  
package NetFox; Y Sux#*#H  
h7J4 p  
 |Fe*t  
public class SiteInfoBean { N7-LgP  
<F ?UdMT4y  
]:.9:RmEV  
private String sSiteURL; //Site's URL GU7f27p  
private String sFilePath; //Saved File's Path }TRVCF1  
private String sFileName; //Saved File's Name b] ~  
private int nSplitter; //Count of Splited Downloading File yeIc Q%  
vQmqYyOc2  
2 >/}-a  
public SiteInfoBean() nTCwLnX(O  
{//nSplitter的缺省值为5 `!y/$7p  
//default value of nSplitter is 5 Ny G?^  
this("","","",5); k;Ask#rs  
} :I8HRkp  
Xd5uF/w  
&;[e  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) '1rO&F  
{ m.ejGm?  
sSiteURL= sURL; fr<V])  
sFilePath = sPath; r=S,/N(1  
sFileName = sName; 5G l:jRu  
this.nSplitter = nSpiltter; ?63ep:QEk  
Y?\PU{ O  
kHd`k.nW  
} 3]h*6 V1$  
Y'76!Y  
<\oD4EE_  
public String getSSiteURL() }s:~E2?In  
{ 1@xdzKua1  
return sSiteURL; gm =LM=  
} 6&_K;  
Z+2 j(  
70.Tm#qh  
public void setSSiteURL(String value) <jG[ z69)  
{ x+EEMv3u:  
sSiteURL = value; YR u#JYti  
} ]|_+lik#  
<KFl4A~  
:*MR$Jf  
public String getSFilePath() tv%B=E!r  
{ aole`PD,l  
return sFilePath; N)4R.}  
} >tE6^7B*  
kY{;(b3Q  
6 tl#AJ-  
public void setSFilePath(String value) {_UOS8j7  
{ Yb4%W-5  
sFilePath = value; vGwpDu\RgX  
} 5em*9Ko  
v(p<88.!m  
009Q#[A  
public String getSFileName() %Ot*k%F  
{ :Z+J t=;  
return sFileName; PxA OKUpI  
} RcOfesW o  
Rd[^)q4d$w  
}#6~/ W  
public void setSFileName(String value) g0#w 4rGF)  
{ -Eoq#ULvR  
sFileName = value; zBc |gx  
} Wpc8T="q  
yw >Frb5p  
u{S"NEc  
public int getNSplitter() \LM.>vJ  
{ KBa0  
return nSplitter; *d9RD~Ee  
} !\!j?z=O8  
+v< \l=  
ij?Ww'p9>  
public void setNSplitter(int nCount) 38GZ_ z}r  
{ . f!dH  
nSplitter = nCount; n?"("Fiw  
} ZE9.r`  
} 1Cw HGO  
 F |aLF{  
<GLn!~Px@5  
/* :QC |N@C  
**Utility.java nH B  
*/ d>V#?1$h  
package NetFox; AWi+xo|  
PJ\k|  
$g),|[ x+(  
public class Utility { hD{ `j  
yW&ka3j\  
=MT'e,T  
public Utility() BZ(I]:oDL  
{ ij1YV2v  
R2JPLvs  
#Hy\l J  
} wF3 MzN=%  
<v=s:^;C0  
//线程睡眠 j4u ["O3  
public static void sleep(int nSecond) .A0fI";Q  
{ h/6^>setz  
try{ rA E5.Q!u  
Thread.sleep(nSecond); ,T$ GOjt  
} i.\ e/9]f  
catch(Exception e) wB&5q!{!  
{ }F"98s W  
e.printStackTrace (); 3W{ !\  
} nLCaik_,m  
} UZ#oaD8H6  
~+ 9v z  
//日志 Ubgn^+AI  
public static void log(String sMsg) wJ7^)tTRF  
{ JW )f'r_f  
System.err.println(sMsg); G4&?O_\;  
} aNA ]hl  
9M5W4&  
g> ~+M  
public static void log(int sMsg) [P6m8%Y|s  
{ (.X)=  
System.err.println(sMsg); FBbaLqgVF{  
} zWH)\>X59  
} `- (<Q;iO  
Gp+\}<^ Z  
%V+"i_{m  
/* w`=O '0d  
**TestMethod.java -/V(Z+dj  
*/ W6_ rSVm  
package NetFox; 2pU'&8  
Y}: 4y$<  
cpALs1j:  
public class TestMethod { >^GV #z  
U|VL+9#hd  
C ocw%Yl  
public TestMethod() j>B*8*Ss  
{ ///xx/weblogic60b2_win.exe - jCj_@n  
try{ |xg_z&dX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); '&dT   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O5Z9`_9<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); UoKVl-  
fileFetch.start(); {u2Zl7]z^  
} .a7RGT3]m  
catch(Exception e){e.printStackTrace ();} %y|pVN!U  
Ff(};$/& W  
\"))P1  
} I:G8B5{J  
s\pukpf@  
elQjPvb  
public static void main(String[] args) yCav;ZS_  
{ oBo*<6  
new TestMethod(); tx~,7TMS/  
} d}':7Np  
} ES AX}uF  
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