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http断点续传简单实现(java)

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/* G U0zlG] C  
**SiteFileFetch.java $v-lG(  
*/ &fiDmUxj  
package NetFox; 4y>G6TD^  
import java.io.*; '9$xOrv  
import java.net.*; [GU!],Y  
qe`W~a9x  
cvn,&G -`  
public class SiteFileFetch extends Thread { ZS^EKz~+  
?uk|x!Ko]  
V [[B~Rs  
SiteInfoBean siteInfoBean = null; //文件信息Bean v*FCE 1HI  
long[] nStartPos; //开始位置 :bLGDEC  
long[] nEndPos; //结束位置 Da?0B9'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }gag?yQ.^  
long nFileLength; //文件长度 Y($"i<rN  
boolean bFirst = true; //是否第一次取文件 XfViLBY( >  
boolean bStop = false; //停止标志 <ywxz1i  
File tmpFile; //文件下载的临时信息 TD!QqLW  
DataOutputStream output; //输出到文件的输出流 r}"T y  
d<`Z{"g NS  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) {3_M&$jN  
public SiteFileFetch(SiteInfoBean bean) throws IOException dkG-Yz~  
{ ,i>5\Yl%  
siteInfoBean = bean; c6BaC@2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *5*d8;@>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6l:CDPhR  
if(tmpFile.exists ()) \DeZY97p%  
{ tnRq?  
bFirst = false; $sGX%u  
read_nPos(); bL swq  
} EBK\.[  
else zVl(?b&CF  
{ u^!-Z)W  
nStartPos = new long[bean.getNSplitter()]; y])xP%q2 O  
nEndPos = new long[bean.getNSplitter()]; dYf Vox;  
} ]7h&ZF  
z4UeUVfZ}  
Pg*ZQE[ME8  
AD*+?%hj  
} s x`C<c~u  
WXO@oZ!  
zcIZJVYA  
public void run() xCoQ>.4p  
{ ]%>;R^HY  
//获得文件长度 9.vHnMcq  
//分割文件 BO/2kL8*  
//实例FileSplitterFetch A4%0  
//启动FileSplitterFetch线程 {^MR^4&}(  
//等待子线程返回 Rjm5{aa-  
try{ ',J3^h!b  
if(bFirst) xV<NeU  
{ MttVgNV  
nFileLength = getFileSize(); <aL$d7  
if(nFileLength == -1) X@|  
{ ro^Y$;G  
System.err.println("File Length is not known!"); bG2 !5m4L  
} 7v%~^l7:x  
else if(nFileLength == -2) ~q-|cl<  
{ W9a H]9b  
System.err.println("File is not access!"); l}:9)nXA{  
} ~[ve?51  
else &*/X*!_HK  
{ //V?rs  
for(int i=0;i<nStartPos.length;i++) (nvSB}?  
{ G^)|c<'M  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /+02 BP  
} |`:Uww+3  
for(int i=0;i<nEndPos.length-1;i++) \$riwL  
{ O3Ks|%1  
nEndPos = nStartPos[i+1]; (MJu3t @  
} =_.Zv  
nEndPos[nEndPos.length-1] = nFileLength; iwrdZLE  
} l ^\5Jr03  
} - Nplx  
T'f E4}rY  
P9X/yZ42  
//启动子线程 ^[^uDE <  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =0x[Sa$&,  
for(int i=0;i<nStartPos.length;i++) )0qXZ gs  
{ VPtA %1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r95$B6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), D/@:wY  
nStartPos,nEndPos,i); bLaD1rnGi  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l3l[jDa,2  
fileSplitterFetch.start(); [dOPOA/d  
} F4">go  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z1^S;#v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?A,gDk/#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8.]dThaq  
nEndPos = " + nFileLength); vP88%I;  
// fileSplitterFetch[nPos.length-1].start(); 2 B5kpmH:  
@f{)]I +f  
[4t_ 83  
//等待子线程结束 f[h=>O  
//int count = 0; =We}&80 x  
//是否结束while循环 n# Z6d`  
boolean breakWhile = false; U/|B IF  
 LDwu?"P!  
I?l*GO+pz  
while(!bStop) >$HMZbsE  
{ a/`fJY6rR  
write_nPos(); 4.CLTy3W  
Utility.sleep(500); GD~3RnGQ{  
breakWhile = true; 7m@pdq5Ub  
"+Xwc+v^  
ad i5h  
for(int i=0;i<nStartPos.length;i++) s~M!yuH  
{ t2tH%%Rs  
if(!fileSplitterFetch.bDownOver) |$7!u DU8  
{ -D{~7&  
breakWhile = false; 1`B5pcuI  
break; z\fD}`^8  
} |MTgKEsn  
} `I_%`15>  
if(breakWhile) VY~WkSi[<  
break; lE=Q(QUr  
]#S.L'  
6mMJ$FY+  
//count++; &e3z)h  
//if(count>4) oaRPYgh4  
// siteStop(); KJcdX9x  
} B'atwgI0  
9r\8  !R  
P#rwYPww\  
System.err.println("文件下载结束!"); q0DoR@  
} w?<:`  
catch(Exception e){e.printStackTrace ();} &AOw(?2  
} P%B1dRa  
r`wL_>"{n  
5\EHu8  
//获得文件长度 'HW(RC0dR  
public long getFileSize() e`#Gq0}8  
{ nV"[WngN  
int nFileLength = -1; 5 BcuLRId:  
try{ >\(Ma3S   
URL url = new URL(siteInfoBean.getSSiteURL()); p*NC nD*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *.voN[$~  
httpConnection.setRequestProperty("User-Agent","NetFox"); +apIp(E+  
"LXLUa03  
My_fm?n  
int responseCode=httpConnection.getResponseCode(); 4ol=YGCI_  
if(responseCode>=400) k]; <PF  
{ sks_>BM  
processErrorCode(responseCode);  /=[M  
return -2; //-2 represent access is error BQ_\8Qt|  
} 7{az %I$h  
sy/J+==  
][wS}~):  
String sHeader; AVNB)K"  
2MB\!fh  
8q_3*++D  
for(int i=1;;i++) owYfrf3ZLX  
{ vaR0`F  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,ulNap"R  
//Utility.log(in.readLine()); &WvJg#f  
sHeader=httpConnection.getHeaderFieldKey(i); '#u2q=n4*  
if(sHeader!=null) bis/Nfr]  
{ iWQBo>x  
if(sHeader.equals("Content-Length")) 3S'V>:  
{ K<Ct  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %z8@;  
break; ?_n.B=H`8  
} CdTmL{Y1  
} `2r21rVntf  
else t$Irr*  
break; B>a`mFM  
} ]~kqPw<R  
} b39;Sv|#  
catch(IOException e){e.printStackTrace ();} >k_Z]J6Pd  
catch(Exception e){e.printStackTrace ();} !v`q%JW(  
 s.GTY@t  
 w8FZXL  
Utility.log(nFileLength); TSHp.ABf  
] ^  
Ds L]o  
return nFileLength; |nU:  
} GXJ3E"_.  
`Rj i=k>  
B;1wnKdj  
//保存下载信息(文件指针位置) L[TL~@T   
private void write_nPos() f()^^+  
{ vbwEX6  
try{ hw~cS7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BIV]4vl-&  
output.writeInt(nStartPos.length); r=&PUT+vt  
for(int i=0;i<nStartPos.length;i++) 0b*a2_|8k  
{ Z][?'^`^!  
// output.writeLong(nPos); n!HFHy2  
output.writeLong(fileSplitterFetch.nStartPos); vc^PXjX  
output.writeLong(fileSplitterFetch.nEndPos); 9Cf^Q3)5o  
} kQVl8KS  
output.close(); ;F~GKn;}  
} qc*+;Wi+5  
catch(IOException e){e.printStackTrace ();} xW"J@OiKL  
catch(Exception e){e.printStackTrace ();} Mh3zl  
} B(^fM!_%-6  
(T'inNbJe  
@&E E/j^  
//读取保存的下载信息(文件指针位置) 3]} W  
private void read_nPos() 66Hu<3X P  
{ >|z=-hqPK  
try{ #/1A:ig  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wJ IJPYTK  
int nCount = input.readInt(); _Q.3X[88C  
nStartPos = new long[nCount]; kAy.o  
nEndPos = new long[nCount]; 8 LaZ5  
for(int i=0;i<nStartPos.length;i++) O8dDoP\F2  
{ I X\&lV  
nStartPos = input.readLong(); \dufKeiS&a  
nEndPos = input.readLong(); 8|7Tk[X1j  
} 6{+~B2Ef  
input.close(); O5k's  
} ;?n*w+6<  
catch(IOException e){e.printStackTrace ();} $T3/*xN  
catch(Exception e){e.printStackTrace ();} 5-]%D(y  
} {MYlW0)~  
4eIu@ ";!  
/I6?t= ?<  
private void processErrorCode(int nErrorCode) hk,Q=};  
{ Oa@X! \  
System.err.println("Error Code : " + nErrorCode); dWm[#,Q?  
} !4oYQB  
#axRg=d?K  
{bc<0  
//停止文件下载 .v;2Q7X  
public void siteStop() h)A+5^:^  
{ A]=?fyPh{'  
bStop = true; 70KXBu<6  
for(int i=0;i<nStartPos.length;i++) {v]>sn;P1  
fileSplitterFetch.splitterStop(); >O\-\L  
9=JU &/!  
Ud{-H_m+  
} c#{<| .  
} F1%' zsv  
//负责部分文件的抓取 7g&_`(  
**FileSplitterFetch.java OQ[>s(`*{  
*/ (<%i8xu 2  
package NetFox; SAo"+%  
Y{p *$  
AA05wpu8  
import java.io.*; \uanQ|Nu  
import java.net.*; F7"Ihb^l  
Gl1`Nx0  
J`"1DlH  
public class FileSplitterFetch extends Thread { dYr#  
lfI[r|  
F ^E(AE  
String sURL; //File URL u)Y#&qA  
long nStartPos; //File Snippet Start Position )k7`!@ID  
long nEndPos; //File Snippet End Position BY \p?79  
int nThreadID; //Thread's ID %LVk%kz  
boolean bDownOver = false; //Downing is over v3]q2*`G#  
boolean bStop = false; //Stop identical E176O[(V=  
FileAccessI fileAccessI = null; //File Access interface d3n TJX  
gNZ^TeT  
1p8E!c{}j  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .s2d  
{ 1/#N{rZ  
this.sURL = sURL; DI$z yj~3  
this.nStartPos = nStart; yyA/x,  
this.nEndPos = nEnd; 9qqEr~  
nThreadID = id; IndNR:"g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _$=xa6YA  
} ;'<K}h  
,#"AWQ  
/pyKTZ|  
public void run() ; 9'*w=V  
{ s;5PHweWf  
while(nStartPos < nEndPos && !bStop) *~:@xMa  
{ zBjqYqZ<+  
-k<.Q=]<t  
t*D[Q$v  
try{ <MfB;M  
URL url = new URL(sURL); 2r* o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h hd n9n  
httpConnection.setRequestProperty("User-Agent","NetFox"); f}+G;a9Nj  
String sProperty = "bytes="+nStartPos+"-"; r/{VL3}F_e  
httpConnection.setRequestProperty("RANGE",sProperty); #lB[]2]N  
Utility.log(sProperty); @9c^{x\4  
c/x(v=LW  
v4ueFEY  
InputStream input = httpConnection.getInputStream(); O%+:fJz6wI  
//logResponseHead(httpConnection); %9zcc)cP  
;yUY|o  
)FHaJ*&d  
byte[] b = new byte[1024]; _5X}&>>lhF  
int nRead; f0^s*V+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <T7y85  
{ [I^SKvM  
nStartPos += fileAccessI.write(b,0,nRead); :X$&g sT/,  
//if(nThreadID == 1) 4wBCs0NIm  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `9wz:s QtP  
} MWB uMF  
}$UuYO/i  
<4! w2vxG  
Utility.log("Thread " + nThreadID + " is over!"); @FbzKHdV/  
bDownOver = true; ]T*{M  
//nPos = fileAccessI.write (b,0,nRead); \ _i`=dx  
} (JM4W "7'  
catch(Exception e){e.printStackTrace ();} gbInSp`4  
} Qe4  
} RCmPZ  
wZOO#&X#r  
10 p+e_@  
//打印回应的头信息 |]I?^:I  
public void logResponseHead(HttpURLConnection con) Ik}*7D  
{ O=-|b kO  
for(int i=1;;i++) Mv9s  
{ ;pULJ}rDb  
String header=con.getHeaderFieldKey(i); O}KT>84M  
if(header!=null) Xz5=fj&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VyI%^S ]sS  
Utility.log(header+" : "+con.getHeaderField(header)); .KB*u*h  
else @E==~ b  
break; ~ib#x~Db  
} @L~y%#  
} '17=1\Ss6;  
gZPJZN/cpz  
f?{Y<M~]  
public void splitterStop() ", |wG7N K  
{ V)0bLR  
bStop = true; HSUr  
} qGh rJ6R!  
8l}|.Q#--  
x Apa+j6I  
} iF 67  
N..u<06j/  
2`Pk@,:_  
/* Lc.7:r  
**FileAccess.java ~ h:^Q  
*//文件访问(定位,写) ^< E,aCy  
package NetFox; ^%<v| Y(X  
import java.io.*; > *_?^F_  
_>aesp%  
JN8k x;@  
public class FileAccessI implements Serializable{ s0`uSQ2X  
IBuuZ.=j2h  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 nY*ODL  
RandomAccessFile oSavedFile; m?m,w$K  
long nPos; qQom=x  
@TH \hr]  
M)LdGN?$  
public FileAccessI() throws IOException SOUA,4  
{ J*;t{M5  
this("",0); v |i(peA#  
} PNKmI  
*%fOE;-?  
m83i6"!H  
public FileAccessI(String sName,long nPos) throws IOException =_UPZ]  
{ )0%<ZVB  
oSavedFile = new RandomAccessFile(sName,"rw"); ("TI~  
this.nPos = nPos; |FNP~5v  
oSavedFile.seek(nPos); ;N j5NB7  
} +fwq9I>L  
uj]GBo=  
F1+2V"~  
public synchronized int write(byte[] b,int nStart,int nLen) ktS0  
{ x/Ds`\  
int n = -1; Q7SS<'(  
try{ $:xUXEi{  
oSavedFile.write(b,nStart,nLen); e@q[Dv'mu  
n = nLen; +}1]8:>cq  
} ooD/QZUE  
catch(IOException e) '2 )d9_ w  
{ c^=:]^  
e.printStackTrace (); 1XZ&X]  
} -p)HH@6a  
NT-du$! u  
pG4Hy$e  
return n; ! [:K/  
}  /!9949XV  
t=pG6U  
#uH1!UQb  
} HD`%Ma Yhc  
*;}!WDr  
7 yi>G  
/* *&U9npN  
**SiteInfoBean.java T0SD|'  
*/ Z$pR_dazU  
package NetFox; C qxP@  
LCdc7  
*(HH71Y  
public class SiteInfoBean { c]n4vhUa5  
XRz.R/  
` Y ut 1N  
private String sSiteURL; //Site's URL p"X\]g^jA>  
private String sFilePath; //Saved File's Path 4dy)g)wM  
private String sFileName; //Saved File's Name :wF(([&4p!  
private int nSplitter; //Count of Splited Downloading File x7/2e{p uu  
p\,lbrv  
Bq _<v)M*  
public SiteInfoBean() F{}z[0  
{//nSplitter的缺省值为5 sn *s7v:  
//default value of nSplitter is 5 :l 7\7IT  
this("","","",5); `  ^6}Dn  
} p]>bN  
d82IEhZ#  
!",@,$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  CZuxH  
{ YGNX+6Lz  
sSiteURL= sURL; zxj!ihs<  
sFilePath = sPath; &,#VhT![  
sFileName = sName; P "%/  
this.nSplitter = nSpiltter; [oYe/<3  
\myj Y  
N-NwGD{  
} )HU?7n.{  
~\Ynih  
&B3kzs  
public String getSSiteURL() .f6_[cS;g  
{ SGbo|Xe7:  
return sSiteURL; 3Fr}8Dy  
} PffwNj/l  
K'71uW>  
L@+j8[3BX  
public void setSSiteURL(String value) ^L[Z+7|  
{ jQ[Z*^"}  
sSiteURL = value; 7kb`o y;(^  
} 5Ut0I]h|z  
BkC(9[Ei  
jb*#!m.l  
public String getSFilePath() m4%m0"Z  
{ J=Jw"? f  
return sFilePath; u}$U|Cw-;T  
} p;B +g X  
jLEU V  
=N3~2=g~A  
public void setSFilePath(String value) Mr&]RTEE  
{ gNO$WY^  
sFilePath = value; :bh[6 F  
} FTB"C[>  
lF#Kg !-l  
0m@S+$v  
public String getSFileName() !X,S2-}"  
{ .a^/r'?  
return sFileName; A8A+ImwO"  
} uIba{9tM"P  
ck^Z,AKL+  
6Z'zB&hM}  
public void setSFileName(String value) p;'vOb  
{ nU`;MW/^w  
sFileName = value; >U}~Hv]  
} `C=p7 %  
m+!%+S1  
x^;n fqn|  
public int getNSplitter() JD>!3>S)?  
{ q!7\`>.2:{  
return nSplitter; kC#;j=K?  
} v<-D>iJ  
|UBJu `%  
ROfmAc  
public void setNSplitter(int nCount) .Kv@p jOr  
{ O}%=c\Pb  
nSplitter = nCount; <Q8bn?Z  
} Z-~^)lo  
} kP|!!N  
L Y M`  
qa Q  
/* n|F`6.G  
**Utility.java .3Ap+V8?  
*/ kBT cN D|  
package NetFox; j9qN!.~mM  
b/G0EcRw+  
I4)vJ0  
public class Utility { Obd!  
`W/6xm(X5;  
wgufk {:  
public Utility() y_nh~&  
{ 7X.1QSuE  
ar{e<&Bny  
>Te{a*`"m:  
} 7eO8cPy  
I?:V EN:  
//线程睡眠 :DZiDJ@  
public static void sleep(int nSecond) 6?Wsg`9  
{ fY `A  
try{ 6v1j*'  
Thread.sleep(nSecond); FX'W%_f,  
} Nn^el' S'  
catch(Exception e) PF+`3  
{ 'R$~U?i8  
e.printStackTrace (); 0q3 :"X  
} <9Chkb|B  
}  Ne4A  
^.4<#Qs  
//日志 NfSe(rd  
public static void log(String sMsg) NT nn!k  
{ ]f\rB8k|&  
System.err.println(sMsg); o 1b#q/  
} 8=e \^Q+  
?@XO*|xkSk  
*7Mrng  
public static void log(int sMsg) II2oV}7?  
{ ;S%wPXj&  
System.err.println(sMsg); :r6 bw  
} >,y QG+  
} c[YC}@l%a  
X ak~He  
m:H )b{  
/* (2{1m#o  
**TestMethod.java ?LW1D+  
*/ 1k7E[G~G|  
package NetFox; M\GS&K$lq  
$pD^O!I)?  
H@6  
public class TestMethod { eD/?$@y  
EEaFi 8  
|GsLcUv6  
public TestMethod() Qejzp/2  
{ ///xx/weblogic60b2_win.exe yZ2,AR%  
try{ MdPwuXI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); g,1\Gj%y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _7;#0B  
SiteFileFetch fileFetch = new SiteFileFetch(bean); sI.Ezuw  
fileFetch.start(); Q'rG' |  
} )h/fr|  
catch(Exception e){e.printStackTrace ();} >sP;B5S  
3}vlj:L  
j jwY{jV  
} fu|I(^NV  
e]5QqM7  
e5AiIVlv  
public static void main(String[] args) I7}[%(~Sf/  
{ &2g1Oy~  
new TestMethod(); D]0#A|n F  
} 1\3n   
} 7+z%O3k'I  
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