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http断点续传简单实现(java)

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/* 6!6R3Za$  
**SiteFileFetch.java \^cXmyQ<%  
*/ cI6Td*vM  
package NetFox; xNJ*TA[+  
import java.io.*; }_}LaEYAo  
import java.net.*; yJw.z#bB#  
6 G ,cc  
1Fsa}UK  
public class SiteFileFetch extends Thread { ubKp P%Z  
vgn,ZcX  
z2A,*|I  
SiteInfoBean siteInfoBean = null; //文件信息Bean z@<jZM  
long[] nStartPos; //开始位置 6 ZXRb  
long[] nEndPos; //结束位置 $7O3+R/=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~A(^<  
long nFileLength; //文件长度 ;b|=osyT\  
boolean bFirst = true; //是否第一次取文件 n "I{aJ]K  
boolean bStop = false; //停止标志 PmE 8O  
File tmpFile; //文件下载的临时信息 /BS yanro  
DataOutputStream output; //输出到文件的输出流 7?y([i\y  
fndH]Yp  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) gd0a,_`M  
public SiteFileFetch(SiteInfoBean bean) throws IOException \Jwc[R&x  
{ 02[*b  
siteInfoBean = bean; Wq25,M'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); gP ^A  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); I!Fd~g9I4  
if(tmpFile.exists ()) Vc8w[oS  
{ `Gg,oCQg  
bFirst = false; 5p7i9"tgn  
read_nPos(); Q ~eh_>"  
} RRpCWc Iv"  
else Gg^gK*D  
{ pe!"!xJE  
nStartPos = new long[bean.getNSplitter()]; y+' ,jM  
nEndPos = new long[bean.getNSplitter()]; ( _MY;S  
} ]0")iY_  
EO/TuKt  
*"V) h I5  
u&j_;Y!6  
} S`h yRw  
#Fh:z4  
S:c d'68D  
public void run() S;u 2B_/  
{ G1SOvdq  
//获得文件长度 TOx@Y$_9Q8  
//分割文件 aC3Qmo6?m  
//实例FileSplitterFetch P(p|NRD@1  
//启动FileSplitterFetch线程 Nm#[A4  
//等待子线程返回 \XbCJJP  
try{ }?6gj%$c  
if(bFirst) MZ^(BOe_  
{ ZQsVSz( 1  
nFileLength = getFileSize(); IRsyy\[kp8  
if(nFileLength == -1) cOdgBi  
{ f5*hOzKG6  
System.err.println("File Length is not known!"); DH])Q5  
} .aC/ g?U  
else if(nFileLength == -2) 2t3)$\ylQp  
{ AD7&-=p&w  
System.err.println("File is not access!"); 0>3Sn\gZ(  
} F ^)( 7}ph  
else ,/eAns`ZU  
{ cZ ,}1?!  
for(int i=0;i<nStartPos.length;i++) rL/H{.@$`  
{ `Js"*[z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1Uc/ r>u9  
} (I#3![q  
for(int i=0;i<nEndPos.length-1;i++) I7;|`jN5K  
{ fHgvh&FU  
nEndPos = nStartPos[i+1]; }n k [WW  
} !dwa. lZ&X  
nEndPos[nEndPos.length-1] = nFileLength; WFfn:WSWU  
} >%c>R'~h  
} l(Uwci  
5C5OLAl v  
!wo  
//启动子线程 ]&"01M~+K  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fy>~ GFk(  
for(int i=0;i<nStartPos.length;i++) j HEt   
{ *dx E (dP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :d|~k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N@I=X-7nh|  
nStartPos,nEndPos,i); ugs9>`fF&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "|/Q5 *L  
fileSplitterFetch.start(); O0sLcuT$  
} Z)<lPg!YAR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;esOe\z jE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \$xj>b;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", CTQJ=R"  
nEndPos = " + nFileLength); FlT5R*m  
// fileSplitterFetch[nPos.length-1].start(); 2CV?cm  
Fm[3Btn  
[G"Va_A8  
//等待子线程结束 CEBa,hp@  
//int count = 0; o`Q.;1(Y'  
//是否结束while循环 CsN^u H  
boolean breakWhile = false; pL2{zW`FDh  
L fZF  
@ el  
while(!bStop) )D&xyC}  
{ k\-h-0[|  
write_nPos(); W@D./Th  
Utility.sleep(500); ?$VkMu$2k  
breakWhile = true; !i\ gCLg2_  
`7R-2 w<b?  
ZWQ/BgKB  
for(int i=0;i<nStartPos.length;i++) @]Lu"h#u=  
{ 9^@)R ED  
if(!fileSplitterFetch.bDownOver) (QQkXlJ  
{ -s]@8VJA"  
breakWhile = false; 9T0g%&  
break; -\2hSIXj  
} >~_)2_j  
} ;3o7>yEv  
if(breakWhile) Rx?ze(  
break; ;*0?C'h=  
d{Owz&PL  
-F MonM  
//count++; .h(iyCxP  
//if(count>4) <LN7+7}  
// siteStop(); Zn[ppsz|  
} qQ 8+gZG$R  
<>)N$$Rx&  
_PSOT5{  
System.err.println("文件下载结束!"); .br6x ^\<  
} 2OQ\ z;s  
catch(Exception e){e.printStackTrace ();} M{4XNE]m  
} l z-I[*bA  
4iss j$  
8e1Z:axn0  
//获得文件长度 x_r*<?OZ  
public long getFileSize() hw(\3h()  
{ B<0Kl.V  
int nFileLength = -1; Sb(OG 6  
try{ h}kJ,n  
URL url = new URL(siteInfoBean.getSSiteURL()); ;%;||?'v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F~eY'~&H}  
httpConnection.setRequestProperty("User-Agent","NetFox"); -+0kay%  
^b.#4i (v  
6[S IDOp*^  
int responseCode=httpConnection.getResponseCode(); "lSh 4X  
if(responseCode>=400) bc3`x1)\^  
{ `evF?t11X  
processErrorCode(responseCode); &xUD (  
return -2; //-2 represent access is error Qqs1%u;e8  
} h~ZLULW)B  
wE}Wh5  
W#=,FZT  
String sHeader; W1EYVXN  
N1B$z3E *  
XK})?LTD  
for(int i=1;;i++) Keem \/  
{ NpaS2q-d  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); IdK<:)Q  
//Utility.log(in.readLine()); n2EPx(~  
sHeader=httpConnection.getHeaderFieldKey(i); PcqS#!t  
if(sHeader!=null) eTuKu(0 E  
{ xF@&wg  
if(sHeader.equals("Content-Length")) jFUpf.v2  
{ >H ?k0M`L  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >##Z}auY  
break; D:/q<<|  
} 3&nN;4~Zx6  
} niKfat?  
else N$x&k$w R  
break; kw E2V+2  
} } `5k^J$x  
} tym:C7v%~  
catch(IOException e){e.printStackTrace ();} ?)186dp  
catch(Exception e){e.printStackTrace ();} lRb>W31"  
T6QRr}8`/J  
Id&e'  
Utility.log(nFileLength); )BvMFwQG  
4QTHBT+2`  
kguZAO6  
return nFileLength; b?c/J {me  
} qR_>41JU"  
{/H<_  
CS~_>bn  
//保存下载信息(文件指针位置) ~$J(it-a  
private void write_nPos() ~UZ3 lN\E  
{ &*%x]fQ@  
try{ x~vNUyEN)  
output = new DataOutputStream(new FileOutputStream(tmpFile)); GEA1y^b6"  
output.writeInt(nStartPos.length); g,rmGu3v  
for(int i=0;i<nStartPos.length;i++) *BdH &U  
{ y.c6r> }  
// output.writeLong(nPos); n:P:im?,y*  
output.writeLong(fileSplitterFetch.nStartPos); h<TZJCt  
output.writeLong(fileSplitterFetch.nEndPos); QS5t~rb  
} E6Z kO/  
output.close(); \2 e^x  
} `$ S&:Q,  
catch(IOException e){e.printStackTrace ();} .7  0  
catch(Exception e){e.printStackTrace ();} 8B:y46  
} o~)o/(>ox  
"ayV8{m^3  
%9a3$OGZX  
//读取保存的下载信息(文件指针位置) BdF/(Pg  
private void read_nPos() yCvtglAJ4  
{ brs`R#e \  
try{ ninWnQq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7HBf^N.  
int nCount = input.readInt(); zh*D2/ r  
nStartPos = new long[nCount]; FK593z  
nEndPos = new long[nCount]; 5a$EXV  
for(int i=0;i<nStartPos.length;i++) [`t ;or  
{ C5Q!_x(  
nStartPos = input.readLong(); )iQ^HZ  
nEndPos = input.readLong(); Dws) 4hH  
} O ~6%Iz`  
input.close(); .Zv~a&GE  
} nqm=snh  
catch(IOException e){e.printStackTrace ();} Z$JJ0X  
catch(Exception e){e.printStackTrace ();} _X~O 6e-!  
} (8)9S6  
BEvY&3%l  
bo/9k 4N3  
private void processErrorCode(int nErrorCode) CV.|~K0O  
{ &h5Y_no GX  
System.err.println("Error Code : " + nErrorCode); fy4zBI@  
} Q_|}~4_+  
%DYh<U4N  
"(7y% TFt:  
//停止文件下载 A*?PH`bY  
public void siteStop() d \l{tmte  
{ rB$~,q&.V  
bStop = true; ,MNv}w@  
for(int i=0;i<nStartPos.length;i++) e ,/]]E/o  
fileSplitterFetch.splitterStop(); Z K+F<}  
jDpA>{O[  
94BH{9b5  
} ={sjoMW  
} z3K$gEve  
//负责部分文件的抓取 3NLn}  
**FileSplitterFetch.java g"1V ]  
*/ jts0ZFHc-  
package NetFox; ,"(G  
)>:~XA|?  
A}(]J!rc  
import java.io.*;  pE)NSZ  
import java.net.*; _&hM6N  
mi7?t/D1Z  
2c 0;P #ol  
public class FileSplitterFetch extends Thread { AX8~w(sv  
6/mz., g2  
,<t.Iz%  
String sURL; //File URL fq6Obh=A#  
long nStartPos; //File Snippet Start Position KtL?,zi  
long nEndPos; //File Snippet End Position E 6TeZ%g  
int nThreadID; //Thread's ID 5 ix*wu`,  
boolean bDownOver = false; //Downing is over 0BlEt1e2T  
boolean bStop = false; //Stop identical f?Zjd&|Ch  
FileAccessI fileAccessI = null; //File Access interface p{^:b6  
4k<o  
@)6b  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^EX"fRwNi  
{ cZNcplt8  
this.sURL = sURL; M/=36{,w-  
this.nStartPos = nStart; ,r w4Lo  
this.nEndPos = nEnd; /B@{w-N  
nThreadID = id; a31e.3 6g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !Ud'(iGa  
} l5{60$g  
UrizZ 5a  
w5HIR/kP  
public void run() hi1Ial\Y  
{ FfJ;r'eGs  
while(nStartPos < nEndPos && !bStop) MF4 (  
{ B@&sG 5ES  
Bdw33z*m  
PlzM`g$A  
try{ ^[x cfTN  
URL url = new URL(sURL); q5SPyfE[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P[ :_"4U  
httpConnection.setRequestProperty("User-Agent","NetFox"); OB(o OPH  
String sProperty = "bytes="+nStartPos+"-"; x950,`zy  
httpConnection.setRequestProperty("RANGE",sProperty); 1RYrUg"s"  
Utility.log(sProperty); 8~C_ng-wn  
VO|ECB2e  
w+ R/>a( ]  
InputStream input = httpConnection.getInputStream(); 2F:qaz  
//logResponseHead(httpConnection); }8ubGMr,Y  
.d1ff] ;  
9;e!r DW,#  
byte[] b = new byte[1024]; .C% 28fH  
int nRead; )y,^M3$?C  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^9[Q;=R  
{ N;g@lyo  
nStartPos += fileAccessI.write(b,0,nRead); :25LQf^nz  
//if(nThreadID == 1) 'Zu S  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y!#-[K:  
}  rL{R=0  
N y'\Q"Y]  
XDemdMy$  
Utility.log("Thread " + nThreadID + " is over!"); Z10Vx2B  
bDownOver = true; k7CKl;Fck  
//nPos = fileAccessI.write (b,0,nRead); ' P?h?w^T  
} faQmkO  
catch(Exception e){e.printStackTrace ();} t%lat./yT  
} rm[C{Pn  
} >$4# G)s  
$d?W1D<A  
G\@pg;0|y  
//打印回应的头信息 ljKIxSvCFp  
public void logResponseHead(HttpURLConnection con) ,;`f* #  
{ Tlw'05\{J  
for(int i=1;;i++) 7Z6=e6/\  
{ ,|]J aZq  
String header=con.getHeaderFieldKey(i); ~#pATPW@(  
if(header!=null) ==dKC;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); MET9rT  
Utility.log(header+" : "+con.getHeaderField(header)); YMX9Z||  
else e}UQN:1  
break; RuPnWx!  
} pE5v~~9Ikv  
} %2}fW\% '  
X;I9\Cp]!  
.{V"Gn9!  
public void splitterStop() $'J3 /C7  
{ k;l3^kTy  
bStop = true; %j7b0pb  
} vY4sU@+V  
AQ~ xjU  
N6Mr#A-{  
} U) J5K  
'$9o(m#  
YWFE*wQ!  
/* ^jL '*&l  
**FileAccess.java R BYhU55B  
*//文件访问(定位,写) |6E_N5~  
package NetFox; }Pcm'o_wT  
import java.io.*; Og\k5.! ,  
9bM\ (s/  
cM#rus?)+  
public class FileAccessI implements Serializable{ 2e`}O  
jxog8 E  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |toP8 6  
RandomAccessFile oSavedFile; yb`PMjj15  
long nPos; C96/   
R_!.vGhkN  
$YSXE :  
public FileAccessI() throws IOException jeC=s~  
{ c[h~=0UtJ  
this("",0); 6mM9p)"$  
} * ,hhX psa  
NAR6q{c  
pXk^EV0  
public FileAccessI(String sName,long nPos) throws IOException R;< q<i_l  
{ J&xZN8jW   
oSavedFile = new RandomAccessFile(sName,"rw"); .GrOdDK$ns  
this.nPos = nPos; `/8@Fj  
oSavedFile.seek(nPos); u^Q`xd1  
} '75T2Ud  
i>m%hbAk  
`'YX>u/  
public synchronized int write(byte[] b,int nStart,int nLen) idI w7hi4  
{ a1Fx|#! mq  
int n = -1; $V~@w.-Z#  
try{ Lljn\5!r<  
oSavedFile.write(b,nStart,nLen); B~]Kqp7yU  
n = nLen;  Gl~l  
} =X$ieXq|  
catch(IOException e) w~66G  
{ $dL..QH^K  
e.printStackTrace (); y* +y&  
} Y}?8  
ula-o)S  
')m!48  
return n; jP+yN|  
} 28MMH Q  
&2 tfj(ms  
?.~1%l!  
} &\h7E   
98[uRywI  
B~Sj#(WEa  
/* &LLU@|  
**SiteInfoBean.java &uq.k{<p\  
*/ &K^0PzWWof  
package NetFox; UC!mp?   
tB_le>rhl  
ai !u+L  
public class SiteInfoBean { v3-/ [-XB:  
/$~1e7 W  
R N$vKJk  
private String sSiteURL; //Site's URL ,B <\a  
private String sFilePath; //Saved File's Path +}:Z9AAMy  
private String sFileName; //Saved File's Name S$mv(C  
private int nSplitter; //Count of Splited Downloading File !=[Y yh  
q}{E![ZTu  
) c@gRb~  
public SiteInfoBean() tLE8+[ SU  
{//nSplitter的缺省值为5 ? x)^f+:9|  
//default value of nSplitter is 5 !]4u"e  
this("","","",5); r4yz{^G  
} eM7@!CdA9q  
f|d~=\0y  
\""^'pP@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Bx?3E^!T  
{ @v-^j  
sSiteURL= sURL; }[p{%:tP  
sFilePath = sPath; h]4xS?6O  
sFileName = sName; xR+vu>f  
this.nSplitter = nSpiltter; N`8K1{>BH  
9CD ei~  
%>|FJ  
} 6= ?0&Bx&  
;_}pIO  
2#wnJdr6E  
public String getSSiteURL() bWe2z~dP  
{ w\buQ6pR)  
return sSiteURL; (.J/Ql0Y  
} MO`Y&<g~A  
\/ bd  
U8_{MY-9}  
public void setSSiteURL(String value) hRkCB  
{  |$Yk)z3  
sSiteURL = value; sI>w#1.m/&  
} t@%w:*&  
^~4]"J};M  
N?\X 2J1  
public String getSFilePath() (Y1*Bs[l  
{ <A3%1 82  
return sFilePath; ni;_Un~  
} K~(RV4oF8B  
DUOoTl p  
8}QM~&&.  
public void setSFilePath(String value) sW>%mnx  
{ fc#9e9R  
sFilePath = value; %4~"$kE  
} Jqoo&T")  
Yh<F-WOo2  
-E-#@s  
public String getSFileName() N_Us6 X  
{ G]lGoa}]`u  
return sFileName; w2LnY1A  
} osp~)icun  
k+QGvgP[4@  
}">r0v!3  
public void setSFileName(String value) Ycr3$n]e  
{ V U3RFl  
sFileName = value; x ;DoQx  
} *>m[ZJd%=  
~Ztn(1N  
+k`L8@a3&  
public int getNSplitter() KzHN|8 $o  
{ [LVXXjkFI  
return nSplitter; |$WHw*F^  
} 9*"  
-]3K#M)s  
(HNc9QVC'W  
public void setNSplitter(int nCount) %\'=Y/yP  
{ vC]X>P5Px  
nSplitter = nCount; *byUqY3(  
} i?T-6{3I  
} W;u.@I&  
\Ec<ch[)c  
sI,cX#h&Y  
/* tU4#7b:Y  
**Utility.java aCZ0-X?c  
*/ ?P9aXwc  
package NetFox; Ym'h vK  
8h] TI_  
*@rA7zPFf  
public class Utility { ]d*9@+Iu  
^ :VH?I=  
C HnclT  
public Utility() K V5 '-Sv1  
{ W8W7<ml0A  
>a"J);p  
()lgd7|+  
} EjP;P}_iK  
6,t6~Uo/  
//线程睡眠 [6VB&   
public static void sleep(int nSecond) Z`TfS+O6  
{ 1/$PxQ  
try{ -2hirA<^  
Thread.sleep(nSecond); c>bns/f  
} b9H(w%7ucU  
catch(Exception e) :8 2T!  
{ #:6-O  
e.printStackTrace (); 7Ae`>5B#  
} X,Ql6uO  
} x`6MAZ  
s&7 3g0$$  
//日志 (~~m8VJ>  
public static void log(String sMsg) w:\} B'u  
{ !5,C"r  
System.err.println(sMsg); ~RR!~q  
} ':.Hz]]/A  
:1+Aj (  
@.;+WQE  
public static void log(int sMsg) *fN+wiPD  
{ # ~<]z  
System.err.println(sMsg); :qm\FsO  
} \[9VeqMU  
} )^:H{1'  
m]qw8BoU`F  
(.-4Jn  
/* -XYvjW,|  
**TestMethod.java D07M!U  
*/ z:Am1B  
package NetFox; ~"+"6zg  
1EU4/6!C  
_=g&^_ #t  
public class TestMethod { 9evr!=":  
n>ryS/1  
'/O:@P5qY  
public TestMethod() MCN>3/81  
{ ///xx/weblogic60b2_win.exe ' ]k<' `b|  
try{ )n&hO_c/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 56AC%_ g>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?L<B]!9HZt  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ' i+L  
fileFetch.start(); tpWGmj fo>  
} xQsxc  
catch(Exception e){e.printStackTrace ();} G+dq */  
sq$v6x sl  
DI\=udN  
} 3)G~ud  
wfo,r 7  
^hLr9k   
public static void main(String[] args) _LJF:E5L  
{ 2yA)SGri  
new TestMethod(); U[wx){[|  
} bq/Aopfr  
} kj6:P$tH  
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