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http断点续传简单实现(java)

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/* PPCZT3c=  
**SiteFileFetch.java wEK@B&DV  
*/ &dSw[C#f  
package NetFox; {},rbQ -  
import java.io.*; HLMEB0zh^  
import java.net.*; c`UJI$Q/  
1XZ|}Xz  
,j~ R ^j  
public class SiteFileFetch extends Thread { b@ J&jE~d  
M,[u}Rf^w  
H~~I6D{8  
SiteInfoBean siteInfoBean = null; //文件信息Bean Ty]/F+{  
long[] nStartPos; //开始位置 !=#230Y  
long[] nEndPos; //结束位置 5G8`zy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Z-m,~Hh  
long nFileLength; //文件长度 SM:SxhrGt  
boolean bFirst = true; //是否第一次取文件 fTi,S)F'  
boolean bStop = false; //停止标志 Xq&x<td  
File tmpFile; //文件下载的临时信息 zE V J  
DataOutputStream output; //输出到文件的输出流 t`{^gt  
sV7dgvVd  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) K[LTw_oE  
public SiteFileFetch(SiteInfoBean bean) throws IOException %g(h%V9f  
{ w $7J)ngA9  
siteInfoBean = bean; ?U0iHg{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .kM74X=S  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (^g?/i1@d  
if(tmpFile.exists ()) 9E _C u2B  
{ 3 uwZ#   
bFirst = false; $ 1(u.Ud  
read_nPos(); V|NWJ7   
} JbYv <  
else [|{yr  
{ d"78w-S  
nStartPos = new long[bean.getNSplitter()]; Co8b0-Z  
nEndPos = new long[bean.getNSplitter()]; 5| 2B@6-  
} 9frx60  
r @~T}<I  
-"5x? \.{m  
o}5:vi]  
} {Ny\9r  
&)Z8Qu  
1Qf21oN{  
public void run() k>{i_`*  
{ uVqJl{e\  
//获得文件长度 s<qSelj  
//分割文件 : o$ R@l  
//实例FileSplitterFetch @u/<^j3Q  
//启动FileSplitterFetch线程 e#k9}n^+  
//等待子线程返回 <9bQAyL9  
try{ c>K/f7  
if(bFirst) PKC``+K i  
{ K_nN|'R-  
nFileLength = getFileSize(); !U]V?Jpi"  
if(nFileLength == -1) CTtF=\  
{  49 3ik  
System.err.println("File Length is not known!"); u0$7k9mE  
} sXTt )J  
else if(nFileLength == -2) ]^gD@].  
{ }M/w 0U0o  
System.err.println("File is not access!"); y{ 90A  
} o<-%)#e  
else nvD"_.KrJ  
{ 1L'[DKb'  
for(int i=0;i<nStartPos.length;i++) ?w# >Cs(  
{ sVkR7 ^KsG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); XrC{{K  
} "<6pp4*I  
for(int i=0;i<nEndPos.length-1;i++) [RD ^@~x  
{ !gy'_Y  
nEndPos = nStartPos[i+1]; aEdF Z  
} <-Q0WP_^  
nEndPos[nEndPos.length-1] = nFileLength; +,>f-kaV  
} 0s0[U  
} 5HG 7M&_  
.mDqZOpf=4  
XoSjYG(>,  
//启动子线程 p"H8;fPA0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r_xo>y~S  
for(int i=0;i<nStartPos.length;i++) O( he  
{ ~B(]0:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d5A!kU _.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), = k3O4gE7  
nStartPos,nEndPos,i); q~trn'X>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |!%A1 wp#  
fileSplitterFetch.start(); *U54x /w|  
} QVn0!R{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [&nwB!kt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); U]R?O5K  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8tA.d.8  
nEndPos = " + nFileLength); [tMf KO  
// fileSplitterFetch[nPos.length-1].start(); + y.IDn^  
,_rarU)[J  
CG9X3%xO%  
//等待子线程结束 )[oU|!@  
//int count = 0; *BXtE8 BU  
//是否结束while循环 RMC|(Q<  
boolean breakWhile = false; `N(.10~  
xxkP4,(p  
*`}_e)(k  
while(!bStop) ? |8&!F  
{ ,zXL8T  
write_nPos(); #EHBS~^  
Utility.sleep(500); YGWb!|Z$  
breakWhile = true; +1d\ZZA|6&  
#-'}r}1ZT  
]Vb#(2<2  
for(int i=0;i<nStartPos.length;i++) =V5.c+  
{ .yTk/x ?  
if(!fileSplitterFetch.bDownOver) sF+0v p  
{ IJ4"X#Q/  
breakWhile = false; lR.a3.~  
break; 1.,mNY^UN  
} e_1mO 5z  
} ,dVCbAS@  
if(breakWhile) c6c^9*,V  
break; nrt0[E-&~  
CCEx>*E6c  
^OBaVb  
//count++; W77JXD93  
//if(count>4) #eUfwd6.Y  
// siteStop(); p,tB  
} xZ@Y`2A':  
22BJOh   
^7"%eWT`  
System.err.println("文件下载结束!"); raqLXO!j  
} 3$Is==>7  
catch(Exception e){e.printStackTrace ();} I.8|kscM  
} 0'py7  
\^#1~Kx  
DGd&x^C  
//获得文件长度 L//sJe  
public long getFileSize() 5ef&Ih.3  
{ mlVv3mVyR<  
int nFileLength = -1; @\"*Z&]8z0  
try{  g u|;C  
URL url = new URL(siteInfoBean.getSSiteURL()); _O!D*=I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >}4]51s  
httpConnection.setRequestProperty("User-Agent","NetFox"); )F~>  
[CUJA  
&R5M&IwL  
int responseCode=httpConnection.getResponseCode(); <khx%<)P  
if(responseCode>=400) vlPE8U=  
{ J,D{dYLDD  
processErrorCode(responseCode); &U=f,9H  
return -2; //-2 represent access is error |E~X]_Y  
} gMGg9U$@  
aDOH3Ri0K!  
K[kmfXKu  
String sHeader; GDcV1$NA  
)_Oc=/c|f  
z5vryhX_Z  
for(int i=1;;i++) }cPV_^{  
{ {``}TsN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?+|tPjg $  
//Utility.log(in.readLine()); Bjo&  
sHeader=httpConnection.getHeaderFieldKey(i); 0ay!tS dN  
if(sHeader!=null) IWWFl6$-  
{ kdHql>0  
if(sHeader.equals("Content-Length")) sN g"JQ  
{ `UI)H*GA8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); > Qtyw.n  
break; gK<-*v  
} h4qR\LX  
} 7 %|>7  
else 19rUvgC{M  
break; +>3c+h,%.  
} rx;U/)~#<  
} X3-1)|g !z  
catch(IOException e){e.printStackTrace ();} nB]Q^~jX  
catch(Exception e){e.printStackTrace ();} X,N@`  
' " tieew  
d+;wDu   
Utility.log(nFileLength); BE+Y qT  
YHA[PF   
sy`s$E d!  
return nFileLength; +|H'I j$  
} 6wd]X-G++  
Q|1bF!#(1  
:$tW9*\KY  
//保存下载信息(文件指针位置) "n e'iJf_(  
private void write_nPos() *]eZ Y  
{ q kKABow  
try{ TkBBHg;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); y2U:( H:l!  
output.writeInt(nStartPos.length); kb:C>Y8!sC  
for(int i=0;i<nStartPos.length;i++) bn`zI~WS  
{ c[y8"M5  
// output.writeLong(nPos); 1v4kN -  
output.writeLong(fileSplitterFetch.nStartPos); cR&xl^BJ  
output.writeLong(fileSplitterFetch.nEndPos); #TWc` 8  
} nGbrWu]w  
output.close(); sy?>e*-{  
} !kcg#+s91  
catch(IOException e){e.printStackTrace ();} .'a|St  
catch(Exception e){e.printStackTrace ();} Za6oYM_z  
} Hj\~sR$L-  
z3C^L  
ul?BKV+3E  
//读取保存的下载信息(文件指针位置) qL P +@wbJ  
private void read_nPos() asi1c y\  
{ X]fw9tZ  
try{ V~_nyjrJM  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S8=4C`>jf  
int nCount = input.readInt(); m?j!0>  
nStartPos = new long[nCount]; 9C$!tz>>+i  
nEndPos = new long[nCount]; #{M -3  
for(int i=0;i<nStartPos.length;i++) 5a ~tp'  
{ *o[%?$8T  
nStartPos = input.readLong(); j vV8`BQ{  
nEndPos = input.readLong(); z~ H Gc"~  
} i njmP9ed  
input.close(); X w8i l  
} H5s85"U#  
catch(IOException e){e.printStackTrace ();} 8j'*IRj*q  
catch(Exception e){e.printStackTrace ();} 752wK|o0|;  
} vdm?d/0(^  
/pU6trIM  
(M+<^3c  
private void processErrorCode(int nErrorCode) FJLJ;]`7+  
{ kpH;D=;  
System.err.println("Error Code : " + nErrorCode); Q 8rtZ  
} R`Lm"5w  
p*0Ve21i,  
#CPPdU$  
//停止文件下载 E(tBN]W.  
public void siteStop() )sf~l6  
{ {h"\JI!  
bStop = true; @__;RVQ  
for(int i=0;i<nStartPos.length;i++) Nd_@J&  
fileSplitterFetch.splitterStop(); `I8^QcP  
ymZ/(:3_  
{ +2cRr.  
} tTGK25&  
} >bN~p  
//负责部分文件的抓取 (UF!Zb]{  
**FileSplitterFetch.java Gme$FWa  
*/ F}]_/cY7B  
package NetFox; Q: O>kCDV  
/6?plt&CA  
y!gM)9vq  
import java.io.*; L"iyjL<M  
import java.net.*; ~ ZL`E  
Fnpn_O XlH  
X~he36-+<  
public class FileSplitterFetch extends Thread { XO#)i6}G  
ik *)j  
0Qp'}_  
String sURL; //File URL ,)$KS*f"*z  
long nStartPos; //File Snippet Start Position 38rZ`O*D  
long nEndPos; //File Snippet End Position 5|CiwQg|,p  
int nThreadID; //Thread's ID 3\n{,Q  
boolean bDownOver = false; //Downing is over #( sNk,^Ax  
boolean bStop = false; //Stop identical =&pN8PEn\  
FileAccessI fileAccessI = null; //File Access interface &fW=5'  
s[q4K  
U"+ ry.3`  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException L~{Vt~H9"  
{ Qe$>Jv5  
this.sURL = sURL; !>< %\K  
this.nStartPos = nStart; o#P3lz  
this.nEndPos = nEnd; {p|%hhTK%  
nThreadID = id; /:` i%E  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 WKl'  
} kqW<e[  
6b70w @P!  
5 ek %d  
public void run() !t Oky  
{ g&3#22z  
while(nStartPos < nEndPos && !bStop) uq4s bkP  
{ dB+GTq=6f  
7NB 9Vu|gD  
1MI7l)D?  
try{ I'9s=~VfY,  
URL url = new URL(sURL); fq'Xy9L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A dEbyL  
httpConnection.setRequestProperty("User-Agent","NetFox"); r?nV Sb|[  
String sProperty = "bytes="+nStartPos+"-"; 'UVv(-  
httpConnection.setRequestProperty("RANGE",sProperty); @CU|3Qg  
Utility.log(sProperty); (+LR u1z  
qH Ga  
iW@Vw{|i I  
InputStream input = httpConnection.getInputStream(); mBZ Dl4 '  
//logResponseHead(httpConnection); "QO/Jls  
C cr+SR2  
oPu|Q^I=  
byte[] b = new byte[1024]; @k+G Cf  
int nRead; wUCDJY:,1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :"P hkR  
{ ]KK ZbEO  
nStartPos += fileAccessI.write(b,0,nRead); :aq>  
//if(nThreadID == 1) /QXs-T}d  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aE\BAbD7  
} '}+X,Usm  
LAY)">*49H  
Flujwh@rg  
Utility.log("Thread " + nThreadID + " is over!"); ?>.g;3E$  
bDownOver = true; 9LEilmPs  
//nPos = fileAccessI.write (b,0,nRead); id tQXwa  
} te*Y]-&I|/  
catch(Exception e){e.printStackTrace ();} <,pLW~2-"  
} C6'*/wq  
} 8gtCY~m  
6eUiI@J  
kE_@5t7O{  
//打印回应的头信息 HS`bto0*  
public void logResponseHead(HttpURLConnection con) i9\\evJs  
{ 12d}#G<q-  
for(int i=1;;i++) %wjB)Mae  
{ :uwRuPI  
String header=con.getHeaderFieldKey(i); mrhp)yF  
if(header!=null) @ oz&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 22/?JWL>  
Utility.log(header+" : "+con.getHeaderField(header)); 9j?hF$L"  
else QR5,_wJ&  
break; (: TGev  
} UiK+c30FU  
} K"k"ml<4E  
]PzTl {]  
r$r&4d Y  
public void splitterStop() k~jKJb-_  
{ L_gsG|xX  
bStop = true; < k+fKl  
} QK?2E   
?St=7a(D  
^KZAYB9C  
} *)NR$9lGv  
{rb-DB-/5M  
<Id1:  
/* F/h:&B:;  
**FileAccess.java )pS_+ZF  
*//文件访问(定位,写) V^ fGRA  
package NetFox; < R|)5/9  
import java.io.*; 7z g)h  
iVq#aXN  
XY!{g(  
public class FileAccessI implements Serializable{ _ 7BF+*T  
nG},v%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6>=-/)p}  
RandomAccessFile oSavedFile; $ o5V$N D  
long nPos; T^'*_*m  
 ?+ -/';  
FI`nRFq)C  
public FileAccessI() throws IOException =MJ-s;raq  
{ T+K` ^xv_L  
this("",0); %;<k(5bhGJ  
} J\xz^%p  
ycrh5*g  
-Ap2NpZ"t  
public FileAccessI(String sName,long nPos) throws IOException ^fE\S5P  
{ @jE d%W  
oSavedFile = new RandomAccessFile(sName,"rw"); } T/}0W]0  
this.nPos = nPos; (RDa,&  
oSavedFile.seek(nPos); rysP)e  
} S om. qD  
[GR|$/(z=  
FtFv<UV  
public synchronized int write(byte[] b,int nStart,int nLen) C`NBHRa>  
{ V4`:Vci Aw  
int n = -1; Ms:KM{T0  
try{ qXrt0s[  
oSavedFile.write(b,nStart,nLen); #JL&]Z+X6  
n = nLen; _'!N q  
} L876$  
catch(IOException e) $ ] W[y=  
{ LsJs Q h  
e.printStackTrace (); d`?U!?Si  
} tDC0-N&6S~  
~j/bCMEf!  
P\q<d  
return n; =E [4H  
} $@[dm)M  
3{Na ZIk  
DA+A >5/  
} ZL4l (&"  
n0+g]|a AF  
V17>j0Ev$W  
/* 9tzoris[~  
**SiteInfoBean.java }zkL[qu;  
*/ c!\.[2n  
package NetFox; iUeV5cB  
qs6Nb'JvQR  
935-{h@k  
public class SiteInfoBean { MB ]#%g&  
j>$=SMc  
XGE 2J  
private String sSiteURL; //Site's URL n9]IBIthe  
private String sFilePath; //Saved File's Path <O \tC81  
private String sFileName; //Saved File's Name 6Gs{nFw  
private int nSplitter; //Count of Splited Downloading File ]regi- LGU  
L!bfh`  
=oo[ Eyr  
public SiteInfoBean() $R A4U<  
{//nSplitter的缺省值为5 tt+>8rxF:;  
//default value of nSplitter is 5 .abyYVrN4?  
this("","","",5); cr76cYq"Q  
} dV5PhP>6  
'ox0o:  
cJxW;WI!,  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) d{QMST2&  
{ &_"ORqn&  
sSiteURL= sURL; SX1X< 9  
sFilePath = sPath; o2;(VSKhS  
sFileName = sName; \p5|}<Sr)  
this.nSplitter = nSpiltter; zb"rMzCH  
SQh+5  
! 9d _Gf-  
} #d7N| 9_  
!OPSSP]-  
,9=gVW{  
public String getSSiteURL() J+{Ou rWt  
{ 8K|J:[7  
return sSiteURL; lbQ6 a  
} AI&qU/}  
1i4WWK7k  
yJDeX1+,  
public void setSSiteURL(String value) /3Jz3  
{ f'1(y\_fb  
sSiteURL = value; c*N50%=4  
} Iq)(UfaSve  
ctp?y  
rpUy$qrRc  
public String getSFilePath() mbF(tSy  
{ ;c1relR2  
return sFilePath; L<bYRGz  
} J"diFz+20  
tS?a){^:c  
9GO}&7   
public void setSFilePath(String value) '#O;mBPNi  
{ bAdiA2VF'  
sFilePath = value; j3 6,w[Y:  
}  ci`zR9Ks  
~ct2`M$TL(  
0z<H(|  
public String getSFileName() Rb)|66&3&  
{ 2$M,*Dnr  
return sFileName; g.9L)L  
} As0 B\  
d'ZS;l   
q<n[.u1@  
public void setSFileName(String value) F;#zN  
{ haCKv   
sFileName = value; cI2Fpf`2Wj  
} ovo/!YJ2  
CK2B  
y>$1 UwQ  
public int getNSplitter() B1E$v(P3M  
{ '0Lov]L  
return nSplitter; nt=x]wEC  
} P^"R4T  
M~als3  
RoX &+~  
public void setNSplitter(int nCount) jk )Vb  
{ 3S5^ `Ag#  
nSplitter = nCount; tmp6hB  
} _l<mu?"  
} y=w`w>%  
(z/jMMms  
{J2#eiF  
/* Zb."*zL  
**Utility.java U 2bzUxK  
*/ .l \r9I(  
package NetFox; _lXt8}:+  
{=3B)+N  
(%bE~Q2P*<  
public class Utility { w#&z]O9r  
Axlm<3<wf"  
IK'F{QPH  
public Utility() b vRB  
{ gY!N3 *:  
L=RGL+f1 _  
f3G1r5x  
} s O=4IBE  
)|pU.K9qZ  
//线程睡眠 l xe`u}[  
public static void sleep(int nSecond) 09d9S`cS\  
{ T6uMFD4 |  
try{ pA.._8(t  
Thread.sleep(nSecond); qp>N^)>  
} -(9O6)Rs$  
catch(Exception e) 7Lg7ei2mN7  
{ } Gr&w-v  
e.printStackTrace (); d`Oe_<  
} xIL#h@dz  
} ;'}'5nO=$  
!" E-\cc'  
//日志 (9]6bd  
public static void log(String sMsg) zT7"VbP  
{ (~&w-w3  
System.err.println(sMsg); BqB |Fo  
} Ns<?b;aK  
q jz3<`7-  
zb:kanb-  
public static void log(int sMsg) =We2^W-{  
{ hm\\'_u  
System.err.println(sMsg); u]E.iXp  
} t`YWwI.  
} 1HbFtU`y~  
u]M\3V.  
99u/fkL  
/*   WK==j1  
**TestMethod.java &yU>2=/T  
*/ IP ,.+:i  
package NetFox; <7'&1= %r  
X?/Lz;,&  
xQU"A2{}>  
public class TestMethod { 3z3_7XI  
c<4F4k7  
 ?Vc0)  
public TestMethod() VI_+v[Hk/  
{ ///xx/weblogic60b2_win.exe ] 8Tzr  
try{ b7Oj<! Wo`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); jj,r <T  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l5k?De_(x  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ORBxD"J&  
fileFetch.start(); : @6mFTV  
} ,h&a9:+i  
catch(Exception e){e.printStackTrace ();} ?:igumeYX  
E'EcP4eL  
Wp[9beI*M  
} ar$*a>'?  
?pG/m%[  
zkexei4^<  
public static void main(String[] args) .'T40=7  
{ {kL&Rv%'  
new TestMethod(); {eQWO.C{  
} GeV+/^u  
} .z-UOyer  
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