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http断点续传简单实现(java)

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/* H5,{Z  
**SiteFileFetch.java dDi 1{s  
*/ HNY{%D  
package NetFox; r;y&Wa  
import java.io.*; jS5e"LMIq  
import java.net.*; J%aW^+O  
'&?47+W  
b[uTt'p}  
public class SiteFileFetch extends Thread { Z B`!@/3X  
vW"x)~B  
}C/}8<  
SiteInfoBean siteInfoBean = null; //文件信息Bean plsf` a  
long[] nStartPos; //开始位置 V3yO_Iqa  
long[] nEndPos; //结束位置 D@[$?^H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x)BG%{h  
long nFileLength; //文件长度 dWR?1sV|e  
boolean bFirst = true; //是否第一次取文件 n-Dr/c4  
boolean bStop = false; //停止标志 SQvicZAN)`  
File tmpFile; //文件下载的临时信息 y3 LWh}~E  
DataOutputStream output; //输出到文件的输出流 4J!1$   
cC"7Vt9b  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 'V4.umj1~  
public SiteFileFetch(SiteInfoBean bean) throws IOException t82Bp[t  
{ IhM-a Y y5  
siteInfoBean = bean; Lg9]kpOpa  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); K.o?g?&<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !h?N)9e  
if(tmpFile.exists ()) bp_3ETK]P  
{ /P^@dL  
bFirst = false; q<oA%yR  
read_nPos(); </bWFW~x  
} mrFMdpaHl%  
else cAVe(:k)  
{ &|9mM=^  
nStartPos = new long[bean.getNSplitter()]; r\@"({q}_-  
nEndPos = new long[bean.getNSplitter()]; /W:}p(>4a  
} Jfo|/JQ  
)lB-D;3[_  
|g8 ]WFc  
g\rujxHlH  
} .a;-7|x  
I #1_  
0Yfk/}5  
public void run() }9Y='+.%^  
{ ~`*:E'/5k]  
//获得文件长度 U!3nn#!yE  
//分割文件 6XFO@c}d  
//实例FileSplitterFetch dMRwQejY{7  
//启动FileSplitterFetch线程 /PPk p9H{  
//等待子线程返回 #kLM=a/_NO  
try{ bTO$B2eh|  
if(bFirst) d`({z]W;  
{ fkRb;aIl  
nFileLength = getFileSize(); <u4GIi <sm  
if(nFileLength == -1) &bBp`h  
{ /I[cj3}{+f  
System.err.println("File Length is not known!"); -d_FB?X  
} j|lg&kN  
else if(nFileLength == -2) Ko/_w_  
{ *$`r)pV%AK  
System.err.println("File is not access!"); CdWGb[uI  
} qaw5<  
else G?3S_3J2  
{ OX8jCW  
for(int i=0;i<nStartPos.length;i++) Q{>9Dg  
{ o }Tv^>L  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~{2@-qcm  
} /%)M lG  
for(int i=0;i<nEndPos.length-1;i++) SB$~Btr  
{ *aG0p&n}  
nEndPos = nStartPos[i+1]; EnwiE  
} -[ ^wYr=  
nEndPos[nEndPos.length-1] = nFileLength; (e F5?I  
} 07/5RFmJ  
} -BEPpwb<g  
?ZTB u[  
27u$VHwb  
//启动子线程 `f6Qd2\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; dE ^(KBF  
for(int i=0;i<nStartPos.length;i++) S1$\D!|1  
{ vaTXu*   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M$! 0ikh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \+cQiN b@  
nStartPos,nEndPos,i); qn+mlduU  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 35&&*$Jm  
fileSplitterFetch.start(); M{~eI  
} }f6.eqBX4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !p0FJ].g,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @M,KA {e  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Bm~>w`1wK  
nEndPos = " + nFileLength); ;uba  
// fileSplitterFetch[nPos.length-1].start(); >!bYuVHA  
HnOF_Twq  
hrS/3c'<Z  
//等待子线程结束 r9*{)"  
//int count = 0; XZKOBq B]  
//是否结束while循环 ghms-.:b8  
boolean breakWhile = false; <<UlFE9"  
k{@z87+&  
Ch7eUTq A@  
while(!bStop) AiO,zjM=  
{ i"_f46r P  
write_nPos(); b~#rUOXb8?  
Utility.sleep(500); hR= 4w$  
breakWhile = true; 4SG[_:+!  
oiFtPki  
n`^</0  
for(int i=0;i<nStartPos.length;i++) (TnYUyFP`  
{ v- {kPc=:#  
if(!fileSplitterFetch.bDownOver) `P# h?tZ  
{ OW #pBeX99  
breakWhile = false; Y61E|:fV!  
break; F." L{g  
} dF FB\|e;0  
} kV(?u_ R  
if(breakWhile) SKcAZC  
break; d]@9kG  
0K#dWc}"a  
:;7qup  
//count++; /iukiWeW  
//if(count>4) CdEJ/G:  
// siteStop(); B<0lif|  
} [2&Fnmjk}X  
W?6RUyMC$T  
+x4o#N  
System.err.println("文件下载结束!"); $6Ty~.RP5H  
} 7L]fCw p[  
catch(Exception e){e.printStackTrace ();} bgEUG  
} PDGh\Y[AK,  
[9>1e  
d[O.UzQ  
//获得文件长度 =Wl CE_  
public long getFileSize() ;zh|*F>  
{ H:~LL0Md%  
int nFileLength = -1; hPEK@  
try{ $(_i>&d<  
URL url = new URL(siteInfoBean.getSSiteURL()); c\RDa|B,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v$,9l+p/  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5gEUE{S  
(# ?~^ut  
sS+9ly{9J  
int responseCode=httpConnection.getResponseCode(); ]INbRytvc  
if(responseCode>=400) )IhI~,0Nmj  
{ 9D 0ujup  
processErrorCode(responseCode); g(<@r2p  
return -2; //-2 represent access is error NB, iC [e  
} +  1v@L  
=;T971L`  
0}w>8L7i{  
String sHeader; U` bvv'38#  
.m+KXlP  
a{H~>d< ?  
for(int i=1;;i++) o3uv"# C  
{ LiN{^g^fx  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]huqZI  
//Utility.log(in.readLine()); * .Kc-f4mP  
sHeader=httpConnection.getHeaderFieldKey(i); "lUw{3  
if(sHeader!=null) Va !HcG1^:  
{ ob0clJX  
if(sHeader.equals("Content-Length")) f PDnkr  
{ w"aD"}3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3RGVH,  
break; Nf3Kz#!B  
} 67J=#%\  
} rJg! 2  
else &z,w0FOre  
break; fe&K2C%bm  
} o[8Y%3  
} Kh%9Oy  
catch(IOException e){e.printStackTrace ();} > Y[{m $-  
catch(Exception e){e.printStackTrace ();} 1UmV &  
o&X!75^G>  
9i9VDk{  
Utility.log(nFileLength); D^f;dT;-  
k^ID  
3+(Fq5I  
return nFileLength; _-&Au%QNJ`  
} ;pC-0m0Y  
]Nm_<%lT  
7';PI!$  
//保存下载信息(文件指针位置) JLs7[W)O  
private void write_nPos() OyTBgS G?a  
{ 3Vt-]DGX  
try{ PUucYc  
output = new DataOutputStream(new FileOutputStream(tmpFile)); A$%%;O   
output.writeInt(nStartPos.length); A;{8\e  
for(int i=0;i<nStartPos.length;i++) #&Biu }4D  
{ ,qaIdw[  
// output.writeLong(nPos); m]&d TZV  
output.writeLong(fileSplitterFetch.nStartPos); >JnEhVRQJ9  
output.writeLong(fileSplitterFetch.nEndPos); ("IRv>} 0  
} C2!POf;GdN  
output.close(); qzmY]N+w|  
} f}#pKsX.  
catch(IOException e){e.printStackTrace ();} +EkZyM~z2  
catch(Exception e){e.printStackTrace ();} Y[*z6gP(  
} bJGT^N@  
dG6Mo76  
Mi:$<fEX  
//读取保存的下载信息(文件指针位置) [N H[n#  
private void read_nPos() Ro? 4tGn  
{ Tb~(?nY5  
try{ >\KBXS}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); syV &Ds)  
int nCount = input.readInt(); V,&s$eQC  
nStartPos = new long[nCount]; C>t1~^Q},9  
nEndPos = new long[nCount]; nh,N (t 9  
for(int i=0;i<nStartPos.length;i++) 2<|+h= &  
{ du`],/ 6  
nStartPos = input.readLong(); d}IVYI  
nEndPos = input.readLong(); lq+FH&  
} '7wWdq  
input.close(); ,AACE7%l  
} JCS$Tm6y<_  
catch(IOException e){e.printStackTrace ();} Vb0hlJb  
catch(Exception e){e.printStackTrace ();} OTalR;:]r  
}  27w]Q_C  
8n1Sy7K!;  
\6nWt6M  
private void processErrorCode(int nErrorCode) /sC$;l  
{ Z]"ktb;+[  
System.err.println("Error Code : " + nErrorCode); `2Ff2D ^ ?  
} =yvyd0|35  
2h u;N  
:DQHb"(  
//停止文件下载 (x#4BI}L9)  
public void siteStop() ;^t<LhN:  
{ QH#|R92:  
bStop = true; O"_FfwO a  
for(int i=0;i<nStartPos.length;i++) *H:;pI WP  
fileSplitterFetch.splitterStop(); \ $z.x-U  
3Pkzzyk_|D  
rzEE |  
} t$R|lv5<  
} >qCUs3}C{*  
//负责部分文件的抓取 (CO8t~J=  
**FileSplitterFetch.java k`kmmb>  
*/ "-(yZigQ  
package NetFox; ; l+3l ez  
%w_h8  
[%z~0\lu8  
import java.io.*; P\N$TYeH  
import java.net.*; tAc[r)xFw  
ZuILDevMD  
C$ nT&06o  
public class FileSplitterFetch extends Thread { El]Rrku  
j$Gb> Ex>  
EKq9m=Ua@o  
String sURL; //File URL VO[s:e9L  
long nStartPos; //File Snippet Start Position !:a pu!  
long nEndPos; //File Snippet End Position @dD70T  
int nThreadID; //Thread's ID UPUO8W)<Z6  
boolean bDownOver = false; //Downing is over ="<+^$7:k  
boolean bStop = false; //Stop identical )!){4c/  
FileAccessI fileAccessI = null; //File Access interface sf7'8+wj>  
>\3=h8zw  
~h  tV*R  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException |"vqM)V$  
{ Y0aO/6  
this.sURL = sURL; l`fjz-eE  
this.nStartPos = nStart; h#'(UZ  
this.nEndPos = nEnd; <~vamim#K  
nThreadID = id; F;5.nKo  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 } 3 RqaIY}  
} %/-Z1Nv*#  
>*B/Wy  
}4  5|  
public void run() WF-B=BRZ  
{ doVBVTk^  
while(nStartPos < nEndPos && !bStop) ~z%K9YcyU  
{ 7*~ rhQ  
w\8grEj  
Cf J@|Rh  
try{ kbBX\*{yh  
URL url = new URL(sURL); L:%; Fx2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _~| j~QE]  
httpConnection.setRequestProperty("User-Agent","NetFox"); =H3 JRRS  
String sProperty = "bytes="+nStartPos+"-"; OGrp {s  
httpConnection.setRequestProperty("RANGE",sProperty); cAV9.VS<L  
Utility.log(sProperty); 2*F["E  
_ B",? }  
(]vHW+'  
InputStream input = httpConnection.getInputStream(); KP -g<Zc  
//logResponseHead(httpConnection); 4(|x@: wxm  
K/ I3r_  
p!|ok #sW  
byte[] b = new byte[1024]; (,[m}Qb?!  
int nRead;  r,!7TuBl  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B&+V%~/  
{ G*3O5m  
nStartPos += fileAccessI.write(b,0,nRead); ?)'j;1_=E3  
//if(nThreadID == 1) #ZeZs31  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DNq=|?qn]  
} o5 @ l!NQ  
Q!z g=_z-  
"Z#97Jc+J  
Utility.log("Thread " + nThreadID + " is over!"); w91{''sK  
bDownOver = true; `BdZqXKG  
//nPos = fileAccessI.write (b,0,nRead); :p%nQF,*f  
} VfAIx]Fa  
catch(Exception e){e.printStackTrace ();} vZq7U]RW  
} &d[&8V5S  
} u&9|9+"N  
HhH[pE  
cRDjpc]  
//打印回应的头信息 ,A h QA  
public void logResponseHead(HttpURLConnection con) K%1'zSAyK  
{ ''s]6Jjw  
for(int i=1;;i++) )PVX)2P_C  
{ 593D/^}D  
String header=con.getHeaderFieldKey(i); `7LN?- T  
if(header!=null) 4?jXbC k~x  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {~.h;'m  
Utility.log(header+" : "+con.getHeaderField(header)); i$?i1z*c}  
else XTXRC$B  
break; RYZh"1S;k  
} pMHY2t  
} V+W,# 5  
66,?f<b  
s>9w+|6Ji  
public void splitterStop() #(?EL@5  
{ XuVbi=pN.2  
bStop = true; %($sj| _l  
} hIuK s5`  
Z6 E-FuO  
dUk^DI,:l  
} % TyR8 %  
X25cU{  
{()8 W r  
/* lGwX.cA!'  
**FileAccess.java LBk1Qw}-  
*//文件访问(定位,写) 6-{QU] #  
package NetFox; RM|<(kq  
import java.io.*; >t.2!Z_RQ  
5lu620o  
BXiuVx  
public class FileAccessI implements Serializable{ JVD#wwic  
B- N  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 AA:Ch?  
RandomAccessFile oSavedFile; Z f4Xt Yn  
long nPos; <*<7p{x  
WFocA:  
<VS\z(K  
public FileAccessI() throws IOException l}&egq DC  
{ n9B1NM5 \  
this("",0); jFZJ #'CNS  
} 3l0x~  
-5l74f!i  
v<,? %(g)7  
public FileAccessI(String sName,long nPos) throws IOException qY]IX9'kV  
{ cxFfAk\,en  
oSavedFile = new RandomAccessFile(sName,"rw"); {a-p/\U  
this.nPos = nPos; S^HuQe!#  
oSavedFile.seek(nPos); *` >(K&  
} U< |kA(5  
r5xu#%hgp;  
r]iec{ ^  
public synchronized int write(byte[] b,int nStart,int nLen) j)?I]j/  
{ iqig~fjK ~  
int n = -1; U{ gJn#e/.  
try{ ]7}2"?J4v  
oSavedFile.write(b,nStart,nLen); eNY$N_P   
n = nLen; 0.4c|-n  
} &Y;z[+(P  
catch(IOException e) r in#lu& N  
{ q %i2' yE  
e.printStackTrace (); `PnB<rf:*1  
} ~Aq;g$IJZ  
NYz{ [LM  
e*;-vS9H  
return n; 7_)'Re#  
} C S"2Sd 1`  
5 5>^H1M  
@[D-2s  
} eVL'Ao&Ho  
a]|P rjPI  
`So*\#\T  
/* `{s:lf  
**SiteInfoBean.java t5G@M&d4Eo  
*/ 3N|,c]|  
package NetFox; /!rH DcR  
dU+28  
tJy6\~  
public class SiteInfoBean { r5t C  
sc\4.Ux%Q  
8q{ %n   
private String sSiteURL; //Site's URL tbrjTeC  
private String sFilePath; //Saved File's Path Fr?o 4E6h  
private String sFileName; //Saved File's Name N>giFj[dD  
private int nSplitter; //Count of Splited Downloading File y)X1!3~(  
`ySLic`  
zFmoo4P/  
public SiteInfoBean() RNE} )B  
{//nSplitter的缺省值为5 kaQn'5  
//default value of nSplitter is 5 m!L&_ Z|j  
this("","","",5); %?1k}(qUeY  
} Jf{6'Ub  
rwGY)9 |  
73OFFKbsk  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8Ih+^Y a  
{ Rm`_0}5  
sSiteURL= sURL; N|Mzj|i.  
sFilePath = sPath; HWG5Ghu8,)  
sFileName = sName; )<-\ F%&b  
this.nSplitter = nSpiltter; k;/U6,LQ*  
_@wXh-nc  
L6c =uN  
} U@yn%k9  
[GJ_]w^}j  
#)QR^ss)iw  
public String getSSiteURL() yyb8l l?@a  
{ NCbn<ojb  
return sSiteURL; xhLVLXZ9  
} ]p~w`_3v  
i7v> 9p7  
BR*,E~%  
public void setSSiteURL(String value) H z&a~  
{ w K0vKdi  
sSiteURL = value; *U|K~dl]K  
} q'9u8b  
.I_Mmaq;i  
*P]FX-D3  
public String getSFilePath() |{]W (/  
{ i;>Yx#  
return sFilePath; 8`l bKV  
} :1NF#-2\f  
Y4 q;  
~'k.'O{  
public void setSFilePath(String value) musZCg$  
{ '|V"!R)  
sFilePath = value; ,\ [R\s  
} YMx]i,u'+  
f-&4x_5  
Q]wM WV  
public String getSFileName() &6V[@gmD  
{ <XG&f  
return sFileName; PLlad\  
} |Am +f.  
L ldZ"%P  
_3v6c  
public void setSFileName(String value) }xXUCU<  
{ 8i"v7}  
sFileName = value;  _dCdyf  
} >qkZn7C   
CR3<9=Lv>  
YQGVQ[P  
public int getNSplitter() OOJg%y*H  
{ BnJpC<xm  
return nSplitter; r/o1a't;  
} IJ >qs8  
nKpXRuFn\  
foO /Yc  
public void setNSplitter(int nCount) L|O[u^  
{ x{y}pH"H  
nSplitter = nCount; ;Qe-y|>  
} L[;U Z)V@  
} WrJgU&H{  
fg"]4&`j-  
+P YX.  
/* mcbvB5U  
**Utility.java =GH>-*qp  
*/ SStaS<q '  
package NetFox; /o@6? UH  
2ZUI~:U Z  
jD]Ci#|W  
public class Utility { 3Wv -olv  
(SMnYh4  
zY_?$9l0  
public Utility() mk*r^k`a  
{ <!@*2/Q]J]  
I_ O8 9Sgn  
^\o3V<  
} U~h f,Oxi  
ppL*#/jYt  
//线程睡眠 r2dU>U*:4  
public static void sleep(int nSecond) %a\!|/;6  
{ k2]fUP  
try{ va6e]p*Oy  
Thread.sleep(nSecond); r:rM~``  
} i3 ?cL4  
catch(Exception e) n[|*[II  
{ K,B qVu  
e.printStackTrace (); i{T mn  
} \0bao<  
} I$yFCdXr  
L TsX{z  
//日志 ~1xfE C/  
public static void log(String sMsg) ( x)}k&B;  
{ <V?csx/eRd  
System.err.println(sMsg); @-B)a Z  
}  al#BfcZW  
=17d7#-  
0<ze'FbV]  
public static void log(int sMsg) 04o>POR  
{ K14FY2"  
System.err.println(sMsg); u?Pec:3%  
} [2~^~K  
} d`eX_]Z  
b({K6#?'[  
S1d^mu  
/* z?Hi u6c-  
**TestMethod.java /2s=;tA1  
*/ Hsdcv~Xr;l  
package NetFox;  kD}w5 U  
ZwzN=03T  
Dt#( fuk#  
public class TestMethod { *P:!lO\|  
/w|!SZB  
V= wWY*C  
public TestMethod() 5)@UpcjUA  
{ ///xx/weblogic60b2_win.exe ?**9hu\BG  
try{ W{@,DQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +mu.W r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |XGj97#M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); S1vUP5cZ  
fileFetch.start(); -e2f8PV?3  
} 5I`_S Oa!  
catch(Exception e){e.printStackTrace ();} Yo-$Z-ud  
T<a/GE/  
>IT19(J;A  
} UR{OrNg*  
s!g06F  
59R%g .2Y  
public static void main(String[] args) ;:WM^S  
{ uge~*S  
new TestMethod(); r*F^8_YMK  
} xGkc_  
} 6d;_}  
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