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http断点续传简单实现(java)

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/* K1uN(T.Ju  
**SiteFileFetch.java D.)$\Caq  
*/ Ou/@!Y1  
package NetFox; @va{&i`%A7  
import java.io.*; ZmO/6_nU?  
import java.net.*; ?6Cbx6  
uoFH{.)  
wE3^6  
public class SiteFileFetch extends Thread { ba|x?kz  
)/2* <jr  
jo=XxA  
SiteInfoBean siteInfoBean = null; //文件信息Bean y=YD4m2W  
long[] nStartPos; //开始位置 &Th/Qv}[  
long[] nEndPos; //结束位置 &5/`6-K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g#`(& k  
long nFileLength; //文件长度 qRsPi0;  
boolean bFirst = true; //是否第一次取文件 Q6Q>b4 .3  
boolean bStop = false; //停止标志 R6dw#;6{I  
File tmpFile; //文件下载的临时信息 =%Gecj  
DataOutputStream output; //输出到文件的输出流 * b>W  
R?1;'pvpa[  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) X obiF  
public SiteFileFetch(SiteInfoBean bean) throws IOException Tz58@VYV  
{ `ea;qWy  
siteInfoBean = bean; u(02{V  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lT$Vv= M  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); tr7FV1p  
if(tmpFile.exists ()) }aXc,;Ps  
{ hd9fD[5  
bFirst = false; AM##:4   
read_nPos(); yXY8 o E  
} TJ7on.;  
else lE08UEk1i  
{ }txHuq1Q.  
nStartPos = new long[bean.getNSplitter()]; 1 Y@6oT  
nEndPos = new long[bean.getNSplitter()]; gj\r>~S  
} ;3Fgy8 T  
+OK.[ji?  
Yg/e8Q2  
5ejdf  
} *gHOH!K,S  
&PD4+%!  
IvetQ+  
public void run() gd.P%KC!g  
{ @z$V(}(O^  
//获得文件长度 v"O{5LM"  
//分割文件 Wf 13Ab  
//实例FileSplitterFetch ywmx6q4MFL  
//启动FileSplitterFetch线程 ^Ot+,l)  
//等待子线程返回 7u,56V?X  
try{ 3nd02:GF  
if(bFirst) {#uX   
{ TuwH?{ FzK  
nFileLength = getFileSize(); f'Wc_ L)  
if(nFileLength == -1) sBS\S  
{ T_6,o[b8  
System.err.println("File Length is not known!"); &of%;>$>M  
} Mp?Ev.  
else if(nFileLength == -2) m^U\l9LE  
{ t?28s/?  
System.err.println("File is not access!"); 9/D+6hJ]:  
} go6Hb>  
else y&lj+j  
{ P\iw[m7O  
for(int i=0;i<nStartPos.length;i++) /+2^xEIjE  
{ .,l ?z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =Z2U  
} en!cu_]t  
for(int i=0;i<nEndPos.length-1;i++) 6 )0$UW  
{ WXNJc  
nEndPos = nStartPos[i+1]; nfy"M),et  
} 8_U*_I7(  
nEndPos[nEndPos.length-1] = nFileLength; -}2q-  
} CeR4's7  
} #E5#{bra  
\`{ YqOT  
>~TLgq*  
//启动子线程 XIJ>\ RF  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -:pLlN-f  
for(int i=0;i<nStartPos.length;i++) itX<!  
{ Mz40([{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D!J ("~[3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9g J`H'  
nStartPos,nEndPos,i); mY(~94{d  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PPDm*,T.  
fileSplitterFetch.start(); .pu]21m=  
} y M , hF  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |w6:mtaS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +H/^RvUjF  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !s\-i6S>  
nEndPos = " + nFileLength); @`$8rck`  
// fileSplitterFetch[nPos.length-1].start(); Eo)Q> AM  
~8`r.1aUO  
e_g7E+6  
//等待子线程结束 0u QqPF t  
//int count = 0; b,D+1'  
//是否结束while循环 & @^|=>L  
boolean breakWhile = false; DDN#w<#  
5Tb93Q@c  
}OI;M^5L  
while(!bStop) Jnb>u*7,  
{ N#C,_ k  
write_nPos(); l *yml  
Utility.sleep(500); bvUjH5.7  
breakWhile = true; bsmZR(EnU  
Cz+`C9#  
@v2_gjRe  
for(int i=0;i<nStartPos.length;i++) N*f?A$u/I  
{ {<v?Z_!68  
if(!fileSplitterFetch.bDownOver) `&LPqb  
{ l <Tkg9  
breakWhile = false; Y#=0C*FS  
break; O8w R#(/  
} G yvEc3|@  
} 2!QJa=  
if(breakWhile) XPBKQm_}  
break; ?R(fxx  
e4fh<0gX  
ve49m%NQ  
//count++; bJ4})P&  
//if(count>4) *P7 H=Yf&  
// siteStop(); h64<F3}  
} !i,Eo-[Z  
vO`~rUA  
v-B{7 ~=#Z  
System.err.println("文件下载结束!"); mSm:>hBd  
} 8oK*NB29  
catch(Exception e){e.printStackTrace ();} ?1T)cd*  
} j^;f {0f  
CBN,~wzP*  
uD0T()J.P5  
//获得文件长度 y-6k<RN  
public long getFileSize() A=JPmsj.  
{ J~Uq'1?  
int nFileLength = -1; D_]4]&QYT  
try{ BCMQ^hP}t  
URL url = new URL(siteInfoBean.getSSiteURL()); uH="l.u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $9YAq/#Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); H(Pzo+k*  
d0``:  
w%~UuJ#i  
int responseCode=httpConnection.getResponseCode(); \e+h">`WgX  
if(responseCode>=400) iY?J3nxD-:  
{ $ha,DlN  
processErrorCode(responseCode); )-VpDW!%_  
return -2; //-2 represent access is error h*d1G9%Q1  
} *lyy|3z  
S9RH&/^H  
!xcLJ5^W  
String sHeader; 0h/bC)z  
D=1:-aLP7  
#0$fZ  
for(int i=1;;i++) CGw,RNV  
{ mO<1&{qMZ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); RwKnNIp  
//Utility.log(in.readLine()); ;$,b w5  
sHeader=httpConnection.getHeaderFieldKey(i); RGEgYOO  
if(sHeader!=null) USd7g Oq(  
{ )hG4,0hv&  
if(sHeader.equals("Content-Length")) W%@r   
{ Z<D8{&AjS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); tE'^O< K  
break; tVQq,_9C  
} "`Q &s  
} f[}(E  
else Gb!R>WY  
break; sg`   
} J4?i\wD:  
} boS=  
catch(IOException e){e.printStackTrace ();} :'`y}'  
catch(Exception e){e.printStackTrace ();} 6}l[%8  
hXnfZx%  
B/O0 ~y!n  
Utility.log(nFileLength); %>'Zy6C<j  
|xawguJ  
j%+>y;).  
return nFileLength; uwl_TDc>%  
} JAx0(MZO  
8+i=u" <  
fHK.q({Qc  
//保存下载信息(文件指针位置) &R5zt]4d&  
private void write_nPos() A=W:}szt]  
{ _mWVZ1P  
try{ ]*?lgwE  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {x{~%)-  
output.writeInt(nStartPos.length); 7F2 WmMS  
for(int i=0;i<nStartPos.length;i++) XEegUTs  
{ ~+ kfb^<-  
// output.writeLong(nPos); 3iM7c.f*/  
output.writeLong(fileSplitterFetch.nStartPos); Vx z`  
output.writeLong(fileSplitterFetch.nEndPos); hT`fAn_  
} tm&,u*6$W?  
output.close(); J6 J">  
} `L LS|S]  
catch(IOException e){e.printStackTrace ();} v]Fw~Y7l!  
catch(Exception e){e.printStackTrace ();} %rlMjF'tG  
} 60e{]}Z  
'dzbeTJ D5  
K$:btWSm  
//读取保存的下载信息(文件指针位置) /M3;~sx  
private void read_nPos() v"%>ms"n  
{ r9b(d]  
try{ k!$$ *a*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  Yy`A0v  
int nCount = input.readInt(); `jhbKgR[  
nStartPos = new long[nCount]; ~+Cl9:4T  
nEndPos = new long[nCount]; rTJqw@]#WH  
for(int i=0;i<nStartPos.length;i++) H+gB|  
{ T-7( 3#&  
nStartPos = input.readLong(); k{lXK\zN  
nEndPos = input.readLong(); 3KkJQ5a  
} R `ob;>[Q  
input.close(); <Zfh5AM  
} |\| v%`r2  
catch(IOException e){e.printStackTrace ();} R{aqn0M  
catch(Exception e){e.printStackTrace ();} 0A8G8^T  
} $DnJ/hg;qD  
!B9 Yw/Ba  
 _PwPLSg  
private void processErrorCode(int nErrorCode) @ IDY7x27  
{ rG[2.\&  
System.err.println("Error Code : " + nErrorCode); Q4S:/"*v8  
} +R{~%ZTK  
w6lx&K-  
^Mhh2v  
//停止文件下载 vJ 28A  
public void siteStop() XMxm2-%olP  
{ !Bg^-F:N  
bStop = true; 5UK}AkEe&x  
for(int i=0;i<nStartPos.length;i++) GGZ9DC\{  
fileSplitterFetch.splitterStop(); #BH]`A J  
30sA\TZ  
{S@, ,  
} oGbh *  
} :qShP3^  
//负责部分文件的抓取 W!=ur,F+  
**FileSplitterFetch.java 5RY-.c4}  
*/ KxFA@3  
package NetFox; >,)U4 6  
fNyXDCl  
ICG:4n(,  
import java.io.*; x%W~@_  
import java.net.*; {aopGu?i  
.~^A!t  
w-@6qMJ  
public class FileSplitterFetch extends Thread { /P/0\3TCi  
=*6H!bzX  
*N6sxFs  
String sURL; //File URL 3YUF\L]yyw  
long nStartPos; //File Snippet Start Position .H&XP W  
long nEndPos; //File Snippet End Position u:wf :^  
int nThreadID; //Thread's ID G%}k_vi&q  
boolean bDownOver = false; //Downing is over 2@N-#x '  
boolean bStop = false; //Stop identical Q } 0_}W  
FileAccessI fileAccessI = null; //File Access interface Udjn.D  
.i#'IS0c  
rTST_$"_6  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException dn_l#$ U  
{ eG.s|0`  
this.sURL = sURL; mMCd   
this.nStartPos = nStart; .^ba*qb`{  
this.nEndPos = nEnd; br?pfs$U  
nThreadID = id; ,~Lx7 5{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 52'6wwv6?  
} T*(mi{[T  
QUz4 Kt  
j5~~%  
public void run() * COC&  
{ }+)q/]%  
while(nStartPos < nEndPos && !bStop) R|*Eg,1g -  
{ w,<n5dMv  
\@{TF((Y  
b<E78B+Aax  
try{ 5n e&6  
URL url = new URL(sURL); 1V,DcolRY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P_.AqEH  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2LCOB&-Ww  
String sProperty = "bytes="+nStartPos+"-"; [[ll4|  
httpConnection.setRequestProperty("RANGE",sProperty); m,rkKhXP  
Utility.log(sProperty); +h1X-K:I  
a3Xd~Qs  
2=VFUR 8  
InputStream input = httpConnection.getInputStream(); `"#hhKG  
//logResponseHead(httpConnection); B~YOU 3  
wOEc~WOd  
srS)"Jt  
byte[] b = new byte[1024]; {=MRJg!U  
int nRead; #9HX"<5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q-yNw0V}F  
{ NjO_Y t  
nStartPos += fileAccessI.write(b,0,nRead); j@/p: fk  
//if(nThreadID == 1) 2~yj =D27Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {}H/N   
} Wo5%@C#M  
wZ_"@j<  
CsjrQ-#9yn  
Utility.log("Thread " + nThreadID + " is over!"); zNg[%{mz  
bDownOver = true; }nSu7)3$B  
//nPos = fileAccessI.write (b,0,nRead); alBnN<UM  
} E%a&6W  
catch(Exception e){e.printStackTrace ();} Zqb*-1Qw"*  
} x{/-&`F  
} TV`sqKW  
-z%->OUu  
Y' 5X4Ks|  
//打印回应的头信息 n'%cO]nSx  
public void logResponseHead(HttpURLConnection con) {Z178sik  
{ *e:2iM)8~  
for(int i=1;;i++) WC b 5  
{ A+FQmLS  
String header=con.getHeaderFieldKey(i); D}U gC\u  
if(header!=null) +fq\K]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); O'QnfpQ*9  
Utility.log(header+" : "+con.getHeaderField(header)); }g:'K  
else Mhc5<~?  
break; Qh* }v!3Jo  
} Dw y|mxlFn  
} fB'Jo<C  
HrT@Df  
GH&5m44   
public void splitterStop() Cu<' b'%;  
{ U!YoZ?  
bStop = true; %Z8pPH~T  
} a)7&2J  
muKu@nshL  
++ObsWZ  
} &vQ5+  
5glEV`.je  
ch0cFF^]  
/* `S4G+j>u6  
**FileAccess.java $-<yX<.  
*//文件访问(定位,写) k0TQFx.A  
package NetFox; fG{3S:TQq  
import java.io.*; fd62m]X  
"Nz"|-3Irv  
6j|~oMYP  
public class FileAccessI implements Serializable{ b{X.lz0  
rA @|nL{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 kV3LFPf>0  
RandomAccessFile oSavedFile; jaMpi^C  
long nPos; m~&>+q ^7  
` M-  
M. _5mZ{  
public FileAccessI() throws IOException = \K/ulZo  
{ |:u5R%  
this("",0); G=C2l# Ae!  
} R@`xS<`L/  
% 3fpIzm  
L3j ~Ooo  
public FileAccessI(String sName,long nPos) throws IOException S(rnVsW%Ki  
{ B}aW y&D  
oSavedFile = new RandomAccessFile(sName,"rw"); 0rif,{"  
this.nPos = nPos; D7c+/H@PF  
oSavedFile.seek(nPos); n*G!=lMji  
} t{B6W)q  
{7v|\6@e3  
zB\ 8<97 C  
public synchronized int write(byte[] b,int nStart,int nLen) jP<6Q|5F  
{ TPY&O{ q  
int n = -1; u{dkUG1ia  
try{ %f(4jQ0I  
oSavedFile.write(b,nStart,nLen); _ -,[U{  
n = nLen; e$mVA}>Ybp  
} M R,A{X  
catch(IOException e) YeB C6`7y  
{ {yi!vw  
e.printStackTrace (); ?wjk=hM2  
} 0\eSiXs  
Cq-99@&;  
Eok8+7g0&  
return n; #}8VUbJ  
} OSom-?|w  
P8tCzjrV  
jT;'T$  
} TQvjU!>  
LOgB_$9_3  
UA#=K+2  
/* `eGp.[ffT  
**SiteInfoBean.java jASK!3pY  
*/ `G>|g^6%i  
package NetFox; ~u?rjkSFoh  
v v   
'OMl9}M  
public class SiteInfoBean { SO~pe$c-  
Yt r*"-  
MJK PpQ(,  
private String sSiteURL; //Site's URL .&K?@T4l  
private String sFilePath; //Saved File's Path XD[9wd5w8  
private String sFileName; //Saved File's Name lHu/pSu@k  
private int nSplitter; //Count of Splited Downloading File 9(bbV5}  
GW9,%}l^;  
'n?"f|G  
public SiteInfoBean() cc"<H}g>`  
{//nSplitter的缺省值为5 aQso<oK  
//default value of nSplitter is 5 q@4Cw&AI+  
this("","","",5); FE06,i\{  
} ~0vNs2D,S  
&3*r-9BZ  
)F0Q2P1I  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B\`${O(  
{ cL"Ral-qB  
sSiteURL= sURL; 5+)_d%v=6!  
sFilePath = sPath; O /h1ew  
sFileName = sName; QKoJxjR=^  
this.nSplitter = nSpiltter; T$V8 n_;  
mrVN&.  
fo I:`]2"*  
} V0gu0+u~R  
W5&KmA  
(c[DQSj  
public String getSSiteURL() <F| S<\Y.  
{ _G)x\K]N  
return sSiteURL; -1R7 8(1  
} 2%]#rZ  
`Cu9y+t  
. ;D'  
public void setSSiteURL(String value) ^brh\M,:@  
{ o K&G  
sSiteURL = value; a$LoQ<f_  
} TQ5kT?/{  
HZ\=NDz  
+H!aE}  
public String getSFilePath()  GU xhn  
{ I#zL-RXT  
return sFilePath; E7]a#  
} *#'&a(h B!  
>SD?MW 1E  
v\XO?UEJ2  
public void setSFilePath(String value) Xd&oERJj  
{ K%/g!t)  
sFilePath = value; 3LVL5y7|  
} |@)jS.Bn  
{_4zm&  
 o7AI  
public String getSFileName() `1R[J4e  
{ +ZRm1q   
return sFileName; o:Tpd 0F  
} _ ^^5  
6V1 Z(K  
}oii|=,#^  
public void setSFileName(String value) j!a&l  
{ qPCI@5n3T?  
sFileName = value; az Oib=3fz  
} X-%91z:o58  
LM".]f!,  
XJ3aaMh"  
public int getNSplitter() hrbeTtqi  
{ yGb^kR}d  
return nSplitter; "K*^%{  
} c*)PS`]t  
&Fch{%S>  
=Flr05}m  
public void setNSplitter(int nCount) ]T>YYz  
{ "6iq_!#L  
nSplitter = nCount; rrZ'Dz  
} 8p~|i97W]!  
} By0Zz  
$tebNi P  
v1E(K09h2  
/* JRw)~Tg @  
**Utility.java zZ])G  
*/ 46c0;E\9  
package NetFox; ?qtL*;  
w{Y:p[}  
rVnolA*%  
public class Utility { <P c;8[  
mmEe@-lE  
~G~:R  
public Utility() 0"`|f0}c  
{ <9?`zo$y  
QWK\6  
}h\]0'S~J~  
} 4&E &{<;  
p,#**g:  
//线程睡眠 e&=T`  
public static void sleep(int nSecond) p87VJ}  
{ ixo?o]Xb`  
try{ Qx[ nR/  
Thread.sleep(nSecond); 5> =Ia@I   
} ZDl(q~4?z  
catch(Exception e) @jH8x!5u:  
{ .cg"M0  
e.printStackTrace (); _gP-$&JC  
} VW\~OH  
} /%h<^YDBf  
N >+L?C  
//日志 \-)augq([  
public static void log(String sMsg) [+4--#&{  
{ &V7{J9  
System.err.println(sMsg); Twr<MXa  
} E3o J;E  
<*74t%AJ%  
8w4cqr4m  
public static void log(int sMsg) ,W~a%8*  
{ ADN  
System.err.println(sMsg); RU GhhK  
} npdpKd+*K"  
} {!7 ^ w  
+"2IQme5  
i^u5j\pfY*  
/* _ Tj`  
**TestMethod.java $^4URH  
*/ ?-IjaDC}  
package NetFox; 'X(G><R9  
geRD2`3;  
.I&]G  
public class TestMethod { l~V^  
F2$Z4%x#  
bC@9 */i  
public TestMethod() ' |>  
{ ///xx/weblogic60b2_win.exe {`vv-[j|  
try{ (lY< \l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Z6I^HG{:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); SMdQ,n1]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); amK.H"  
fileFetch.start(); Fn~?YN  
} ^s&1,  
catch(Exception e){e.printStackTrace ();} 2_]"9d4  
 XVKR}I  
2nGQD{  
} > %U  
H,H=y},  
wLf=a^c#  
public static void main(String[] args) GCTf/V\#  
{ ,#P eK(  
new TestMethod(); f._FwD  
} n-7|{1U  
} ,!?&LdPt>  
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