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http断点续传简单实现(java)

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/* 'QG xd!4  
**SiteFileFetch.java w _u\pa  
*/ osciZ'~  
package NetFox; [N FFB96  
import java.io.*; iF*:d  
import java.net.*; LO'**}vm  
-Q2, "  
cy*?&~;  
public class SiteFileFetch extends Thread { *EI6dD"  
5 VRYO"D:  
/xG*,YL/q  
SiteInfoBean siteInfoBean = null; //文件信息Bean s J\BF  
long[] nStartPos; //开始位置 HPpR.  
long[] nEndPos; //结束位置 7t3X)Ah  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |VKK#J/  
long nFileLength; //文件长度 #w;v0&p  
boolean bFirst = true; //是否第一次取文件 rI{=WPI&WU  
boolean bStop = false; //停止标志 +U:$(UV'A  
File tmpFile; //文件下载的临时信息 z^KJ*E  
DataOutputStream output; //输出到文件的输出流 _my"%@n  
w;D+y*2  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) *RT>`,t/  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6~OoFm5  
{ y@]_+2Vo  
siteInfoBean = bean; wWgWWXGT}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9K/HO!z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); X#d~zk[r2  
if(tmpFile.exists ()) J2d.f}-  
{ $v,dz_O*\  
bFirst = false; yH7F''O7  
read_nPos(); 8][nmjk0  
} X$%'  
else nvca."5y  
{ S(QpM.9*  
nStartPos = new long[bean.getNSplitter()]; U!T~!C^  
nEndPos = new long[bean.getNSplitter()]; eeIhed9  
} 832v"k CD  
,/[6e\0~  
rMXN[,|v  
Z/Eb:  
} <wZQc  
Rn#KfI:{  
so PLA68  
public void run() ]&?Y~"{cD  
{ 3WN`y8l  
//获得文件长度 "rTQG6`  
//分割文件 Q)"C&) `l  
//实例FileSplitterFetch 0YaA`  
//启动FileSplitterFetch线程 KuWWUjCE  
//等待子线程返回 h a|C&G  
try{ n-5W*zk1  
if(bFirst) 'AzDP;6qFI  
{ Y_}mYvJW  
nFileLength = getFileSize(); uB |Ss  
if(nFileLength == -1) `/_o!(Z`  
{ r/& sub"X  
System.err.println("File Length is not known!"); $Vsk Ew"|M  
} sLh==V;9  
else if(nFileLength == -2) t c[n&X  
{ D@G\7 KH@  
System.err.println("File is not access!"); )64@2 ~4y  
} BeCWa>54i  
else ^ K|;~}P  
{ %R1tJ(/  
for(int i=0;i<nStartPos.length;i++) LY6;.d$J  
{ XXbqQhf  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ag$Vgl  
} .b\$MZ"(  
for(int i=0;i<nEndPos.length-1;i++) 0MV>"aV  
{ (]_1  
nEndPos = nStartPos[i+1]; ^?$WVB  
} vK(i 9>;7  
nEndPos[nEndPos.length-1] = nFileLength; e'~Zo9`r6  
} AGH|"EWG  
} g wz7krUTe  
1<+2kBuY  
*eIJwXE  
//启动子线程 'jmTXWq*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +${D  
for(int i=0;i<nStartPos.length;i++) D*Ik7Pe  
{ fKp#\tCc y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p7);uF^O%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), RZ6xdq}>  
nStartPos,nEndPos,i); Ys -T0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !(q sD+  
fileSplitterFetch.start(); GQ*wc?f3  
} z?>D_NLX6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SaC d0. h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ".SJ~`S  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Kh(ZU^{n  
nEndPos = " + nFileLength); / y A7%2  
// fileSplitterFetch[nPos.length-1].start(); !E,A7s  
KQ `qpX^d  
_8Z_`@0  
//等待子线程结束 R-NS,i={  
//int count = 0; Q9U f.Lh2  
//是否结束while循环 /D5`   
boolean breakWhile = false; ;=geHiQHA  
!1n8vzs"c  
fR)m%m  
while(!bStop) ]BtbWKJBqe  
{ 6 }4'E  
write_nPos(); ak ->ML  
Utility.sleep(500); z?[r  
breakWhile = true; BJgW,huLy  
}K1JU`Lz  
ikSF)r;*t  
for(int i=0;i<nStartPos.length;i++) $B kubWM  
{ Glxuz0]  
if(!fileSplitterFetch.bDownOver) N;Dni#tQ`  
{ z^_*&  
breakWhile = false; zS\E/.X2  
break; n8uv#DsdK  
} \ {qI4=  
} xfy1pS.[:  
if(breakWhile) _ ):d`O e  
break; [vMvV4,  
#?*WPq  
5nTY ?<x`k  
//count++; `(v='$6}  
//if(count>4) O=v#{ [  
// siteStop(); -od!J\ KCy  
} fbWFLS m;  
L f"i !  
c~{9a_G  
System.err.println("文件下载结束!"); {~h*2n  
} .,7JAkB%t  
catch(Exception e){e.printStackTrace ();} zUkN 0  
} JoRT&rkd  
bV edFm  
e%4:) IV!;  
//获得文件长度 S!Omy:=;i  
public long getFileSize() >ELlnE8  
{ }"|"Q7H  
int nFileLength = -1; e{X6i^% m_  
try{ Dfps gY)/?  
URL url = new URL(siteInfoBean.getSSiteURL()); YY&l?*M<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S-7'it!1  
httpConnection.setRequestProperty("User-Agent","NetFox"); D\@m6=L  
h G gx  
0dA7pY9  
int responseCode=httpConnection.getResponseCode(); Pt@%4 :&-h  
if(responseCode>=400) @HRC \OG  
{ ,ldI2 ]  
processErrorCode(responseCode); [,K.*ZQi  
return -2; //-2 represent access is error CT KG9 T  
} VOc8q-hK  
<&&SX;  
j [rB"N`0  
String sHeader; neXeAU  
-zp0S*iP7  
?OE.O/~l  
for(int i=1;;i++) k% sO 0  
{ is1's[  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;w6>"O$a  
//Utility.log(in.readLine()); }j2Y5  
sHeader=httpConnection.getHeaderFieldKey(i); rC.eyq,105  
if(sHeader!=null) <V7>?U l  
{ VA"*6F   
if(sHeader.equals("Content-Length")) Xg=x7\V  
{ 6`0mta Q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); j4>a(  
break; e$u4vC~  
} zaFt*~@X  
} sp7*_&'J  
else 'WI^nZM  
break; ybeKiv9  
} Yly@ww9t|  
} \k]x;S<a  
catch(IOException e){e.printStackTrace ();} B!dU>0&Ct  
catch(Exception e){e.printStackTrace ();} =/u% c!  
pG34Qw  
V7Z4T6j4  
Utility.log(nFileLength); o]ag"Q  
t~e<z81p  
~_9n.C  
return nFileLength; b{d4xU8'  
} ) c/% NiN  
< -uc."6\  
i.xXb [M+  
//保存下载信息(文件指针位置) $xOI 1|d   
private void write_nPos() )mJf|W!Z#  
{ U9&k;`  
try{ ?_oF:*~\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); [F_/2+e  
output.writeInt(nStartPos.length); [97KBoSU  
for(int i=0;i<nStartPos.length;i++) e/*$^i+S  
{ |.F  
// output.writeLong(nPos); j ,)P9V  
output.writeLong(fileSplitterFetch.nStartPos); DbZ0e5  
output.writeLong(fileSplitterFetch.nEndPos); (faK+z,*6R  
} %*o8L6Hn  
output.close(); 'qArf   
} B d^"=+c4  
catch(IOException e){e.printStackTrace ();} Fhv2V,nZ<  
catch(Exception e){e.printStackTrace ();} G/d4f?RU  
} Q|,B*b  
K*IxUz(  
l akp  
//读取保存的下载信息(文件指针位置) #Ei,(xiP  
private void read_nPos() 6oinidB[l  
{ l{:a1^[>y  
try{ 8K;Y2 #  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); GyW.2  
int nCount = input.readInt(); 3;7q`  
nStartPos = new long[nCount]; dLvJh#`o  
nEndPos = new long[nCount]; =(EI~N  
for(int i=0;i<nStartPos.length;i++) X53mzs  
{ 4"@GNk~e  
nStartPos = input.readLong(); x lsqj`=  
nEndPos = input.readLong(); 4g}FB+[u  
} R#n%cXc|  
input.close(); R*zO dxY  
} Y7GF$}%UL  
catch(IOException e){e.printStackTrace ();} tp:\j@dB  
catch(Exception e){e.printStackTrace ();} >tG+?Y'{  
} ? b[n|^wS  
,;<RW]r-P  
sBK <zR  
private void processErrorCode(int nErrorCode) 7 uMd ZpD  
{ T *I?9d{k  
System.err.println("Error Code : " + nErrorCode); tu>{  
} [EY`am8[  
nRb^<cZf  
c=[q(|+O!  
//停止文件下载 a`E*\O'd  
public void siteStop() _Cy:]2o  
{ #5&jt@NS  
bStop = true; .fzu"XAPu  
for(int i=0;i<nStartPos.length;i++) kvGCbRC  
fileSplitterFetch.splitterStop(); 'r} zY-FM`  
<w>/^|]#  
?Pwx~[<1""  
} D -IR!js ]  
} H^~.mBP n  
//负责部分文件的抓取 -fgC" 2H  
**FileSplitterFetch.java ' )-M\'S$E  
*/ lFUWV)J\  
package NetFox; NQ|xM"MqD  
z[#Fog  
VW@ x=m  
import java.io.*; t` 8!AhOgc  
import java.net.*; }wwe}E-e  
\aP6_g:N}  
`7+j0kV)  
public class FileSplitterFetch extends Thread { (QB+%2v  
4ZC!SgJo  
64j|}wJ$  
String sURL; //File URL hzY[ G :  
long nStartPos; //File Snippet Start Position sk2%  
long nEndPos; //File Snippet End Position Y'`"9Db  
int nThreadID; //Thread's ID .wK1El{bf  
boolean bDownOver = false; //Downing is over Y\+KoR' ;  
boolean bStop = false; //Stop identical [m'CR 4(|  
FileAccessI fileAccessI = null; //File Access interface oc{EuW{Ag  
[U\(G  
=l942p  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException d"~(T:=r  
{ rrs"N3!aT  
this.sURL = sURL; E1Q0k5@  
this.nStartPos = nStart; e kQrW%\3  
this.nEndPos = nEnd; kw,$NK'  
nThreadID = id; Y7U&Q:5'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1;| LI?  
} 2GWDEgI1o  
b^`AJK  
ohc1 ~?3b  
public void run() Bmo$5$  
{ {hqAnZ@]vr  
while(nStartPos < nEndPos && !bStop) :Gh~fm3}  
{ ad n|N  
NvtM3  
Wv K(G3  
try{ {.k)2{  
URL url = new URL(sURL); 7;LO2<|1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h<p3'  
httpConnection.setRequestProperty("User-Agent","NetFox"); -NM0LTF  
String sProperty = "bytes="+nStartPos+"-"; hPdx(E)8!d  
httpConnection.setRequestProperty("RANGE",sProperty); H5nS%D  
Utility.log(sProperty); ^m7~:=K7WG  
xi'<y  
8NimZ(  
InputStream input = httpConnection.getInputStream(); Mth6-^g5  
//logResponseHead(httpConnection); 7w58L:)B.  
TYjA:d9YH  
=qoRS0Qa  
byte[] b = new byte[1024]; 2H[)1|]l  
int nRead; ~U}Mv{ y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0,FC YTtj$  
{ Ie'P#e'  
nStartPos += fileAccessI.write(b,0,nRead); o;`!kIQ  
//if(nThreadID == 1) QLb MPS  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;vO@m!h}U  
} 6~5$s1Yc  
'pP-rdx  
`1p 8C%  
Utility.log("Thread " + nThreadID + " is over!"); mVm4fHEYwU  
bDownOver = true; Rt= X% [YL  
//nPos = fileAccessI.write (b,0,nRead); J(h3]J/Yw  
} zTCP )x  
catch(Exception e){e.printStackTrace ();} D\]&8w6&  
} 5n:71$6[  
} ;Gm>O7"|@  
r(uP!n1+  
(;6s)z  
//打印回应的头信息 ,9ml>ji`=  
public void logResponseHead(HttpURLConnection con) sms1%%~  
{ 8?jxDW a  
for(int i=1;;i++) bY#;E;'7  
{ _|n=cC4Qu  
String header=con.getHeaderFieldKey(i); U6WG?$x  
if(header!=null) c<qe[iyt/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VEh]p5D  
Utility.log(header+" : "+con.getHeaderField(header)); PHR#>ZD  
else +cfziQ$'  
break; JmWR{du  
} #q4*]qGHm  
} =B5E0x  
w@N{ @tG  
fwmLJ5o N  
public void splitterStop() 9[>Lp9l'  
{ ^o%_W0_r  
bStop = true; e)pTC97^L  
} Hc!!tbBQ  
jmW^`%;7  
~Q!~eTw  
} 5~\Kj#PBx  
q]v,  
c2b6B.4  
/* _:,.yRez  
**FileAccess.java w yD%x(  
*//文件访问(定位,写) I #l;~a<9z  
package NetFox; >_#)3K1y8  
import java.io.*; GAJ~$AiwHH  
P06 . 1  
Ve:&'~F2 s  
public class FileAccessI implements Serializable{ |(%AM*n  
Z% Z"VoxH  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ggCr-  
RandomAccessFile oSavedFile; T <A   
long nPos; ^_w*XV  
@aB9%An1  
}=pOiILvD  
public FileAccessI() throws IOException ` !kL1oUYE  
{ 7x+=7,BZd  
this("",0); FuMq|S  
} r } 7:#XQ  
Hs<n^fyf  
e 2*F;.)  
public FileAccessI(String sName,long nPos) throws IOException LV=^jsQ5  
{ -R@JIe_28f  
oSavedFile = new RandomAccessFile(sName,"rw"); ,^+#M{Z  
this.nPos = nPos; 2E$i_jc  
oSavedFile.seek(nPos); s*{mT6s+T  
} m3%ef  
LY1KQuY  
ftW{C1,U7  
public synchronized int write(byte[] b,int nStart,int nLen) +G\0L_B  
{ O2@" w23  
int n = -1; v|y<_Ya  
try{ 4^MSX+zt  
oSavedFile.write(b,nStart,nLen); z6}Pj>1  
n = nLen; Uf[T_  
} F(G<* lA  
catch(IOException e) 3#<'[TF00t  
{ y"Ihr5S\  
e.printStackTrace (); 9C1b^^Kb  
} *?b@>_1K  
"0<Sd?Sz  
iiehrK&T !  
return n; l) iv\j  
} %30T{n:  
I W8.  
g?$e^ls  
} z-)*Q  
7n<#y;wo  
}RDb1~6C  
/* Z3I L8  
**SiteInfoBean.java xK=J.>h3  
*/ IPkA7VhFF  
package NetFox; ~e+0c'n\  
IF$^ 0q  
'@S,V/jy0z  
public class SiteInfoBean { HD~jU>}}  
J,`_,T  
j`+0.Zlq  
private String sSiteURL; //Site's URL 1 O- E],  
private String sFilePath; //Saved File's Path v?%0~!  
private String sFileName; //Saved File's Name Flne=ij6g  
private int nSplitter; //Count of Splited Downloading File uJm#{[  
&:C{/QnA  
3P3:F2S R  
public SiteInfoBean() `L+ ~&M  
{//nSplitter的缺省值为5 bA0uGLc  
//default value of nSplitter is 5 xan/ay>  
this("","","",5); &,_?>.\[<  
} qU}lGf!dVn  
hQP6@KIe)  
o9~h%&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `6n!$Cxo  
{ qYDj*wqf  
sSiteURL= sURL; PGMv(}%;  
sFilePath = sPath; % Mw'e/?  
sFileName = sName; T&mbXMN  
this.nSplitter = nSpiltter; e%'z=%(  
vx PDC~3;  
q!9^#c  
} @OBHAoz%/  
J]$er0`LY  
)Xq@v']%~9  
public String getSSiteURL() HgS<Vxmq  
{ 65;|cmjv  
return sSiteURL; /kAwe *)  
} BQ5_s,VM  
(q~R5)D  
V> 1D1  
public void setSSiteURL(String value) XTIu(f|d_;  
{ JgxE|#*7U  
sSiteURL = value; L,yA<yrC  
} 'E@2I9Kj  
uT'-B7N  
#: dR^zr<  
public String getSFilePath() C,9)V5!tP2  
{ B#| Z`mZ  
return sFilePath; :Pj W:]  
} g?w2J6Z.`J  
u'#`yTB6b  
uDpf2(>s  
public void setSFilePath(String value) 87&KQ_  
{ ev)rOcOU  
sFilePath = value; 7W6eiUI'  
} `4$4bXrP'  
D)f5pEq'  
MT;SRAmUr  
public String getSFileName() 6#OL ;Y]_  
{ k'6<jEbk  
return sFileName; Fl8w7LcF7  
} 2]?w~qjWm  
/ c4;3>I S  
!G+n"-h9'  
public void setSFileName(String value) aW52.X z%8  
{ j|3g(_v4W  
sFileName = value; o+]Y=r2  
} CpUI|Rs  
D{Hh#x8Y  
^zBjG/'7  
public int getNSplitter() bE VO<x+  
{ '*o7_Ez-{  
return nSplitter; bd@*vu}?}  
} %s~NQ;Y  
N1D6D$s0  
ORV}j, Ym  
public void setNSplitter(int nCount) V%X:1 8j  
{ c^i"}2+  
nSplitter = nCount; 3bT6W, J4T  
} [[";1l  
} ;zfQ3$@9  
< fojX\}3  
Fw(b1d>E  
/* ZXF AuF  
**Utility.java &:!ZT=  
*/ &4w\6IR  
package NetFox; V6DBKq  
XgwMppacw  
6Tm Rc  
public class Utility { \;3B?8wbIl  
 ;'2`M  
3i@ "D  
public Utility() $V`KrA~]  
{ 1YF+(fk  
0U>t>&,"  
>z fq*_  
} ::3iXk)  
 kg/+vJ  
//线程睡眠 y(aAp.S>  
public static void sleep(int nSecond) )[@YHE5g  
{ Z@>=&  
try{ 7yqSt)/U  
Thread.sleep(nSecond); I =tyQ`  
} =Do3#Xe2V  
catch(Exception e) 2$j Ot}  
{ F_p3:l  
e.printStackTrace (); &;~2sEo,  
} p]1yd;Jt  
} Ef,7zKG  
v -|P_O&z  
//日志 QoT3;<r}  
public static void log(String sMsg) h a,=LV  
{ 4."o.:8x  
System.err.println(sMsg); U- *8%>Qp  
} n!l./>N  
g "K#&  
jE?\Yv3  
public static void log(int sMsg) Y^94iOk%T  
{ (_i vN  
System.err.println(sMsg); )$l9xx[  
} 7 BnenHD  
} .%J?T5D  
U'Ja\Ek/f  
I\Gp9w0f  
/* d0H  
**TestMethod.java \CJx=[3(  
*/ ; $ ?jR c  
package NetFox; c`$`0}  
c:@OX[##  
UpszCY4  
public class TestMethod { UgD'Bi  
:9!0 Rm  
V&4:nIS>z  
public TestMethod() U Qi^udGFD  
{ ///xx/weblogic60b2_win.exe uJ)=+Exii  
try{ Y|0-m#1F#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q563,s  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >Xh(`^}SQ*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); avxn}*:X.  
fileFetch.start(); U$/Hp#~X  
} e>vUkP y  
catch(Exception e){e.printStackTrace ();} Hh/ -^G  
YPff)0Nh  
C tC`:!Q  
} ?`l=!>C4s  
4MtqQq4%  
c~L6fvS  
public static void main(String[] args) ~&[P` Z$  
{ PkCeV]`w  
new TestMethod(); Hdq/E>u  
} U@v8H!p^i  
} Y?vm%t`K  
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