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http断点续传简单实现(java)

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/* qqe2,X?  
**SiteFileFetch.java Y%/ YFO2vb  
*/ f#v#)Gp+  
package NetFox; ]<q}WjXD'  
import java.io.*; 7rdw`  
import java.net.*;  L%WME8PB  
;V~rWzKM(  
e?!L}^f6X  
public class SiteFileFetch extends Thread { jJUGZVM6)  
z+k=|RMau  
Q=(@K4  
SiteInfoBean siteInfoBean = null; //文件信息Bean /^'Bgnez  
long[] nStartPos; //开始位置 U=kx`j>  
long[] nEndPos; //结束位置 *qPdZ   
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Uvh~B^6  
long nFileLength; //文件长度 CZyz;Jtk  
boolean bFirst = true; //是否第一次取文件 .kc"E  
boolean bStop = false; //停止标志 0iJ!K;A2%  
File tmpFile; //文件下载的临时信息 fVDDYo2\  
DataOutputStream output; //输出到文件的输出流 jC%35bi  
sTtX$&Qu  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ufw3H9F(O  
public SiteFileFetch(SiteInfoBean bean) throws IOException z.3<{-n}0i  
{ Qz@IK:B}  
siteInfoBean = bean; oTCzYY  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `/O`OrZ1K  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Tm)GC_  
if(tmpFile.exists ()) OJP5k/U$  
{ <b d1  
bFirst = false; 8K0X[-hs8  
read_nPos(); q^ a|wTC  
} D<U 9m3  
else bmOqeUgB  
{ OXHvT/L`  
nStartPos = new long[bean.getNSplitter()]; C$<"w,  
nEndPos = new long[bean.getNSplitter()]; VEj$^bpp5s  
} S]&8St  
#bT8QbJ(  
ryxYcEM0  
+T0op4  
} O' +"d%2'  
Q2/MnM  
L[?nST18%  
public void run() Kt W6AZJ  
{ "z^(dF|  
//获得文件长度 q,B3ru.?d  
//分割文件 e>l,(ql  
//实例FileSplitterFetch i:o}!RZ>  
//启动FileSplitterFetch线程 ZFS7{:  
//等待子线程返回  nbI= r+  
try{ A4G,}r *n  
if(bFirst) (CdJ;-@D  
{ VF)uu[ f9  
nFileLength = getFileSize(); Y1{B c<tC  
if(nFileLength == -1) D ]OD.  
{ HA6G)x  
System.err.println("File Length is not known!"); . yZm^&  
} QsiJ%O Q  
else if(nFileLength == -2) Q}kfM^i  
{ P+<BOG|m  
System.err.println("File is not access!"); ^P`NMSw  
} wV\%R,bZj  
else iF!mV5#  
{ Sd},_Kh  
for(int i=0;i<nStartPos.length;i++) /X4yB"J>  
{ zfhTc=(/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?c!:81+\  
} Q48+O?&  
for(int i=0;i<nEndPos.length-1;i++) F4Zn5&.)  
{ 3VmI0gsm.>  
nEndPos = nStartPos[i+1]; b~7Jh:%@;  
} 1Cm~X$S.  
nEndPos[nEndPos.length-1] = nFileLength; %*lp< D  
} Q1Ux!$_  
} E&*: jDg  
C+w__gO&r  
Z@3l%p6V  
//启动子线程 '>@4(=I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; V vu(`9u]  
for(int i=0;i<nStartPos.length;i++) |h}B{D  
{ <FY&h#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x(8n 9Q>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >1 @Ltvm  
nStartPos,nEndPos,i); `)32&\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ueDvMP  
fileSplitterFetch.start(); St@l]u9  
} Ekv89swl`i  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <I; 5wv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); B2 c@kru  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e,HMwD  
nEndPos = " + nFileLength); j{"z4Y4  
// fileSplitterFetch[nPos.length-1].start(); +$47v$p  
}j46L1T  
.WvlaPK  
//等待子线程结束 P z ?m>>#  
//int count = 0; 1dFa@<5  
//是否结束while循环 +\0T\;-Xe  
boolean breakWhile = false; OL'P]=U  
n`(~O O  
-4w%Iy  
while(!bStop) |uI?ySF  
{ =m7H)z)i*J  
write_nPos(); igDG}q3jG  
Utility.sleep(500); `>6T&  
breakWhile = true; a2`%gh W3  
]H ~Y7\N-v  
!9;)N,  
for(int i=0;i<nStartPos.length;i++) =O!|IAe#  
{ @x1 %)1  
if(!fileSplitterFetch.bDownOver) !Xj#@e  
{ qI%&ay"/  
breakWhile = false; .2.qR,"j  
break; u-JpI-8h  
} #)s!}X^  
} { p;shs5  
if(breakWhile) 3e%nA8?  
break; FJeiY#us  
2Il8f  
x)SralWb  
//count++; 3J~0O2  
//if(count>4) W @.Ji B  
// siteStop(); j8++R&1f]  
} f'X9HU{Cz  
;au*V5a%  
,zhJY ?sk  
System.err.println("文件下载结束!"); 2N5`'  
} e_.Gw"/Yl  
catch(Exception e){e.printStackTrace ();} :^i^0dC  
} rh!;|xB|+  
7" 4z+w  
HeLG?6  
//获得文件长度 p@~ic#X  
public long getFileSize() PT'MNH  
{ >oGiIYq  
int nFileLength = -1; _V2xA88  
try{ |A\a4f 'G  
URL url = new URL(siteInfoBean.getSSiteURL()); "?3`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #Exp51  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;),"M{"v  
Es!Q8.  
IXpc,l `  
int responseCode=httpConnection.getResponseCode(); jq-l5})h  
if(responseCode>=400) h|D0z_f  
{ ;W]\rft[  
processErrorCode(responseCode); +lE90y  
return -2; //-2 represent access is error 8)L*AdDAW!  
} /@"Y^  
:g6n,p_#  
jZteooJG|  
String sHeader; s@8w-]"  
-TO\'^][X  
t~``md4  
for(int i=1;;i++) 3Fs5RC~a  
{ X6\ sF"E  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); CrC =A=e  
//Utility.log(in.readLine()); H1/?+N}(  
sHeader=httpConnection.getHeaderFieldKey(i); B07v^!Z>  
if(sHeader!=null) YJ_\Ns+Ow  
{ zmI]cD@G  
if(sHeader.equals("Content-Length")) *JX;|S  
{ z//VlB  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?'s6Xmd  
break; - +> 1r  
} :o46rBs  
} q?):oJ  
else 1yQejw  
break; =LkR!R=  
} 'Gl&Pa1g?  
} C0jj(ku&  
catch(IOException e){e.printStackTrace ();} }}&#|)Yq  
catch(Exception e){e.printStackTrace ();} GZip\S4Y  
A\fb<  
v{aq`uH  
Utility.log(nFileLength); piy`zc- yu  
q%Yn;g|_  
up>c$jJ  
return nFileLength; 3^?ZG^V  
} 30>3 !Xqa  
,m_WR7!$E  
Lfog {Vzs  
//保存下载信息(文件指针位置) #]P9b@@e  
private void write_nPos() nUS| sh  
{ !3X0FNGq  
try{ y5r4+2B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); T 20&F  
output.writeInt(nStartPos.length);  -I.d}[  
for(int i=0;i<nStartPos.length;i++) t.p~\6Yi  
{ 5 Xn.CBd]  
// output.writeLong(nPos); 8[vc?+>&  
output.writeLong(fileSplitterFetch.nStartPos); @$9'@")  
output.writeLong(fileSplitterFetch.nEndPos); F$BbYf2i  
} */:uV B,b2  
output.close(); >-8cU_m7s  
} 6;'dUGvH  
catch(IOException e){e.printStackTrace ();} qz?mh4Oh  
catch(Exception e){e.printStackTrace ();} M(x$xAiD  
} b~=0[Rv  
8N&+7FK  
R;,g1m|]  
//读取保存的下载信息(文件指针位置) &>d:R_Q]  
private void read_nPos() ApBWuXp|u  
{ F8-?dpf'  
try{ R^?/' dr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2c6g>?  
int nCount = input.readInt(); #Cpd9|  
nStartPos = new long[nCount]; ?;[w" `"  
nEndPos = new long[nCount]; wLc4Dm*V  
for(int i=0;i<nStartPos.length;i++) 1 zw*/dp  
{ Ym%xx!9  
nStartPos = input.readLong(); wE+${B03  
nEndPos = input.readLong(); .*m>\>Gsgw  
} 7 d LuX   
input.close(); ;AO#xv+#  
} IxLhU45  
catch(IOException e){e.printStackTrace ();} q9Y9w(  
catch(Exception e){e.printStackTrace ();} .7K7h^*F  
} `]Q:-h  
'AN>`\mR$  
=[b)1FUp  
private void processErrorCode(int nErrorCode) q`-;AG|xF  
{ /1Ue?)g  
System.err.println("Error Code : " + nErrorCode); X 1 57$  
} okbQ<{9  
DC{>TC[p1k  
rj(T~d4  
//停止文件下载 }gJ(DbnV  
public void siteStop() T5a*z}L5  
{ h1'\:N`  
bStop = true; lpz2 m\  
for(int i=0;i<nStartPos.length;i++) PRHCrHs  
fileSplitterFetch.splitterStop(); Fu!RhsW5j  
CHe>OreiS  
89r DyRJ;  
} dFKM 8_jH  
} sI{ M  
//负责部分文件的抓取 phM>.y_  
**FileSplitterFetch.java |*}4 m'c  
*/ BD(Z5+EU1  
package NetFox; L 4!{h|  
~\J}Kqg  
tH-C8Qxy  
import java.io.*; 1t)il^p4[;  
import java.net.*; Y "/]|'p  
o!)3?  
)c `7( nY  
public class FileSplitterFetch extends Thread { 7(pF[LCF  
yu;P +G  
xg3:}LQ  
String sURL; //File URL dq]0X?[6  
long nStartPos; //File Snippet Start Position rzt Ru  
long nEndPos; //File Snippet End Position ZIQ [bE7  
int nThreadID; //Thread's ID %}%Qc6.H  
boolean bDownOver = false; //Downing is over Z]B~{!W1  
boolean bStop = false; //Stop identical @nux9MX<9  
FileAccessI fileAccessI = null; //File Access interface v%q0OX>9X"  
<yd{tD$A*  
_H5o'>=  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HSc~*Q  
{ 1fpQLaT  
this.sURL = sURL; 8P|D13- Q  
this.nStartPos = nStart; DAXX;4  
this.nEndPos = nEnd; e J6$-r  
nThreadID = id; q^Y-}=w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'Iw NTM  
} <ZNzVnVA  
RS8Hf~0G  
ME*LH r,  
public void run() y!_C/!d  
{ [5SD_dN  
while(nStartPos < nEndPos && !bStop) z*a:L}$  
{ MB]<Dyj,  
`Tv[DIVW  
a6uJYhS~  
try{ |>dI/_'  
URL url = new URL(sURL); fTK3,s1=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?`PvL!'  
httpConnection.setRequestProperty("User-Agent","NetFox"); lE4HM$p   
String sProperty = "bytes="+nStartPos+"-"; $w`=z<2yo1  
httpConnection.setRequestProperty("RANGE",sProperty); =`H@%  
Utility.log(sProperty); 'F9jq  
]SLP}Jwy  
9-fLz?J  
InputStream input = httpConnection.getInputStream(); Xg;}R:g '  
//logResponseHead(httpConnection); cWe"%I  
v@ lM3_rbO  
-#N.X_F  
byte[] b = new byte[1024]; VgZsB$Ori  
int nRead; q1d}{DU  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9,:l8  
{ F^];U+J  
nStartPos += fileAccessI.write(b,0,nRead); <+?7H\b  
//if(nThreadID == 1) mc? Vq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dtRwTUMe?  
} woGAf)vV#  
0"28'  
9 a!$z!.  
Utility.log("Thread " + nThreadID + " is over!"); $#9;)8J  
bDownOver = true; .uMn0PE   
//nPos = fileAccessI.write (b,0,nRead); o<pf#tifv  
}  +|n*b  
catch(Exception e){e.printStackTrace ();} JR@`2YP-  
} hG12ZZD  
} EVsC >rz  
PgF* 1  
0dE@c./R i  
//打印回应的头信息 VJ]JjB j  
public void logResponseHead(HttpURLConnection con) CVL3VT1j0  
{ T[UN@^DP(  
for(int i=1;;i++) svcK?^ HTe  
{ 5YeM%%-S  
String header=con.getHeaderFieldKey(i); I 8`VNA&b  
if(header!=null)  3KlbP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gd`!tRcNY  
Utility.log(header+" : "+con.getHeaderField(header)); i@"@9n~  
else M_/7D|xl/T  
break; q_A!'sm@)  
} Vt:~q{9*k  
} iT gt}]L  
OR~8sU  
P3+5?.p.  
public void splitterStop() 4%>$-($  
{ s(/; U2"e  
bStop = true; ^/I 7|u]  
} 7&jTtKLj  
 ]hk  
CQF:Rnb  
} zPn+ V7F  
ls\WXCH  
+hg3I8q:  
/* qouhuH_WtJ  
**FileAccess.java ! >(7+B3E*  
*//文件访问(定位,写) #Z?A2r!1  
package NetFox; xpV|\2C  
import java.io.*; pjKWtY@=X  
_.tVSV p  
#+ 0M2Sa  
public class FileAccessI implements Serializable{ 4":KoS`,j  
} gyj0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p& y<I6a,  
RandomAccessFile oSavedFile; ey7 f9  
long nPos; c}lb%^;)E  
DE}K~}sbd  
?~BC#B\>o  
public FileAccessI() throws IOException Aza /6OL  
{ 4KhV|#-;k  
this("",0);  HSjlD{R  
} [kVS O  
?pW`cFLDHF  
,1~"eGl!  
public FileAccessI(String sName,long nPos) throws IOException [M]  
{ Q 3hKk$Y  
oSavedFile = new RandomAccessFile(sName,"rw"); XRM_x:+]  
this.nPos = nPos; -; s|  
oSavedFile.seek(nPos); u%&`}g  
} ^S4d:-.3  
@'#,D!U  
jl4rbzse  
public synchronized int write(byte[] b,int nStart,int nLen) SE@LYeC}dE  
{ (5$!MUS~9  
int n = -1; =)0,#9k U]  
try{ n,vct<&z@  
oSavedFile.write(b,nStart,nLen); \ :%(q/v"X  
n = nLen; sXLq*b?  
} F&4rO\aC"/  
catch(IOException e) yZ0-wI  
{ ^n*)7K[  
e.printStackTrace (); }^ApJS(FQ  
} {fPy=,>Nb  
ne>pOK<vZ  
*>Ns_su7W  
return n; ;km`P|<U  
} wL+s8#{  
,;EIh}  
tqz3zIQ  
} 3@etRd;]Kr  
FvaUsOy "  
H*d9l2,KZS  
/* K^ vIUZ>  
**SiteInfoBean.java Y+kfBvxyf  
*/ g#"zQvON  
package NetFox;  L O}@dL  
F|'>NL-=  
>~''&vdsk\  
public class SiteInfoBean { {BP{C=p  
JA %J$d  
H9'$C/w  
private String sSiteURL; //Site's URL 3atBX5  
private String sFilePath; //Saved File's Path vNyf64)  
private String sFileName; //Saved File's Name Zd3S:),&  
private int nSplitter; //Count of Splited Downloading File Gj1&tjK  
p2hB8zL  
8v:T.o;<  
public SiteInfoBean() `LrHKb aP  
{//nSplitter的缺省值为5 DBo%fYst  
//default value of nSplitter is 5 \Z?9{J  
this("","","",5); ~uj#4>3T  
} 6|gCuT4  
6LvW?z(J  
>BV^H.SO|1  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g{7.r-uu  
{ _'#n6^Us<  
sSiteURL= sURL; B7VH<;Z  
sFilePath = sPath; Uf1!qP/H?  
sFileName = sName; `fA@hK   
this.nSplitter = nSpiltter; RFi S@.7  
>Rl"  
&xU[E!2H%  
} C(eTR1  
?j'7l=94A  
DEBB()6,  
public String getSSiteURL() iJ ($YvF4  
{ Y[ j6u\y  
return sSiteURL; f&=AA@jLv  
} XPavReGf  
h&M{]E9=  
\S"isz  
public void setSSiteURL(String value) .r|tSfm6  
{ &pP;Neh;  
sSiteURL = value; 034iK[ib"  
} |T<_5Ik  
'50OgF'  
K='z G*$l  
public String getSFilePath() /74QMx?  
{ ;nI] !g:  
return sFilePath; 0%32=k7O[  
} ]V[q(-Jk  
ntu5{L'8  
v3*_9e  
public void setSFilePath(String value) fZ6MSAh  
{ yjO1 Ol  
sFilePath = value; .H escg/S  
} \Q {m9fE  
_jvxc'6  
[xK3F+  
public String getSFileName() B+$%*%b  
{ n"h `5p5'  
return sFileName; MH =%-S   
} OstQqV%@  
GiJ *Wp  
i"1Mfz~e  
public void setSFileName(String value) O+nEXS\rQ  
{ jkQ*D(;p  
sFileName = value; t^UxR@l<K|  
} ud63f` W]4  
JL`-0P<M  
pD8+ 4;A  
public int getNSplitter() ~jWn4 \  
{ @CNi{. RX  
return nSplitter; bc7/V#W  
} 3BzNi'  
!-g{[19\  
]dF ,:8  
public void setNSplitter(int nCount) <S5BDk  
{ UgRhWV~f0  
nSplitter = nCount;  |{&{  
} d}OTO10  
} , xw#NG6  
imVo<Je7z(  
UI0( =>L  
/* !({}(!P .  
**Utility.java a`wc\T^  
*/ FW;m\vu  
package NetFox; , |0}<%  
.14~J6  
4%{,] q\p  
public class Utility { I^* Nqqq  
0!D4pvlt  
>|J`s~?  
public Utility() \0A3]l  
{ hl;u'_AB  
<c*FCblv  
4aug{}h("  
} [Hx0`Nc K  
0}<|7?  
//线程睡眠 3t.l5m Rg5  
public static void sleep(int nSecond) Z3%}ajPu[  
{ #^#PPO  
try{ CVDV)#JA  
Thread.sleep(nSecond); 36.Z0Z1'F>  
} _PPy44r2  
catch(Exception e) 2"COP>  
{ MO[2~`,Q!  
e.printStackTrace (); q~rEq%tk  
} QER?i;-wb  
} H h4WMZJG  
at@G/?  
//日志 *$#W]bO  
public static void log(String sMsg) <g-9T-Ky  
{ .Q<>-3\K  
System.err.println(sMsg); "x%Htq@  
} 3v(*5  
=-tw5], L  
3\AU 72-  
public static void log(int sMsg) YP 6` L  
{ -<6\1J  
System.err.println(sMsg); } j<)L,  
} __uA}f Zp  
} _,kj:R.  
:{{F *FM;  
97Lte5c6r  
/* rr/B= O7  
**TestMethod.java XWn VgY s  
*/ N1}c9}  
package NetFox; MlcR"gl*  
{vs uPY  
|U~<3.:m:  
public class TestMethod { lVd^ ^T*fh  
*F WMn.  
+2(I1  
public TestMethod() iyN:%ofh  
{ ///xx/weblogic60b2_win.exe 'Jiw@t<o3`  
try{ 9y6-/H ,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,y1PbA0m  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); # q~e^A b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xg30x C[  
fileFetch.start(); Gw=B:kGk  
} ?yZ+D z\  
catch(Exception e){e.printStackTrace ();} N%kt3vmQ_  
zofa-7'Bn  
toLV4BtIG  
} #||}R[~P"  
`CBZhI%%  
16w|O |^<  
public static void main(String[] args) m&xW6!x  
{ Y)1PB+  
new TestMethod(); lvdf^b/ j  
} A8xvo/n$  
} P|^f0Rw3.  
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