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http断点续传简单实现(java)

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/* V^En8  
**SiteFileFetch.java "{( [!  
*/ ( V4G<-jG  
package NetFox; t _\MAK  
import java.io.*; {A3 m+_8  
import java.net.*; I,j3bC  
hTw}X.<4  
;r!\-]5$  
public class SiteFileFetch extends Thread { 0&$xX!]  
e2Jp'93o'  
8^X]z|2  
SiteInfoBean siteInfoBean = null; //文件信息Bean },PBqWe  
long[] nStartPos; //开始位置 UC|JAZL  
long[] nEndPos; //结束位置 hTTfJDF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Hsl{rN  
long nFileLength; //文件长度 HV\"T(8 9  
boolean bFirst = true; //是否第一次取文件 jo0Pd_W8&  
boolean bStop = false; //停止标志 CG9ba |  
File tmpFile; //文件下载的临时信息 3!Bj{;A  
DataOutputStream output; //输出到文件的输出流 xOIg|2^8  
BKA]G)G7u!  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) BXA]9eK  
public SiteFileFetch(SiteInfoBean bean) throws IOException _?b;0{93u  
{ $4Y&j}R  
siteInfoBean = bean; }17bV, t  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0yTQ{'Cc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); QUp?i  
if(tmpFile.exists ()) *<k&#D"m  
{ DV,DB\P$  
bFirst = false; Jvj=I82  
read_nPos(); GCH[lb>IJv  
} UUm |@  
else XnY"oDg^>  
{ ]) n0MF)p  
nStartPos = new long[bean.getNSplitter()]; g7Z9F[d  
nEndPos = new long[bean.getNSplitter()]; DMMLzS0A  
}  _8S4Q!  
d*%Mv[X:<  
rIlBH*aT  
5_aw. s>  
} $e1:Q#den2  
V6+Zh>'S  
%MuaW(I o  
public void run() oCA(FQ6  
{ f0FP9t3k  
//获得文件长度 !a[$)c  
//分割文件 w\DspF  
//实例FileSplitterFetch \G3!TwC%  
//启动FileSplitterFetch线程 [B,p,Q"  
//等待子线程返回 2 `&<bt[g  
try{ dXO=ZU/N  
if(bFirst) KpGUq0d@  
{ TkT-$=i  
nFileLength = getFileSize(); %~\  
if(nFileLength == -1) gvo?([j-m  
{ _ n_sfT6)B  
System.err.println("File Length is not known!"); |."G?*  
} 8m7;x/0ld  
else if(nFileLength == -2) LE| <O  
{ f9F2U )  
System.err.println("File is not access!"); m&cvU>lC  
} I-{^[pp  
else  ~me\  
{ e>!E=J)j  
for(int i=0;i<nStartPos.length;i++) kjX7- ZPY  
{ b[0S=e G  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); B_tQeM  
} kp; &cQu!  
for(int i=0;i<nEndPos.length-1;i++) Nm"<!a<F  
{ C9pnU,[  
nEndPos = nStartPos[i+1]; N(BiOLZL6  
} j%5a+(H,z;  
nEndPos[nEndPos.length-1] = nFileLength; x~Cz?ljbn  
} HTN$ >QTI  
} 3W'FcE)|E  
o}W;Co  
',#   
//启动子线程 "ZqEP R)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ZM 8U]0[X  
for(int i=0;i<nStartPos.length;i++) BPiiexTV9  
{ E [*0Bo]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7vq DZg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Dt|fDw$]D  
nStartPos,nEndPos,i); yDuq6`R*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Pl?}>G  
fileSplitterFetch.start(); vG3M5G  
} ki4Xp'IK  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uAT/6@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `x*/UCy\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", KcnjF^k  
nEndPos = " + nFileLength); 94YA2_f;  
// fileSplitterFetch[nPos.length-1].start(); 369Zu4|u  
FH[#yq.Pr  
kz_M;h>  
//等待子线程结束 ]Y=S  
//int count = 0; lfgtcR{l5  
//是否结束while循环 :ovt?q8">  
boolean breakWhile = false; Kk>DYHZ6y  
sy=dY@W^  
U\?+s2I)v  
while(!bStop) ,0,Oe=d  
{ ?#i|>MRR>  
write_nPos(); jf8w7T  
Utility.sleep(500); kAt RY4p  
breakWhile = true; GqMB^Ad  
L^x5&CCwk  
X7b!;%3@  
for(int i=0;i<nStartPos.length;i++) | F8]Xnds  
{ L, #Byao  
if(!fileSplitterFetch.bDownOver) S<9gyW  
{ hWm0$v 1p  
breakWhile = false; $i -zMa  
break; df yrn%^Ia  
} #XfT1  
} 3jS7 uU  
if(breakWhile) &rcdr+'  
break; s4N,^_j  
xlk5Gob*  
;8uHRcdQ  
//count++; E;$$+rA  
//if(count>4) ]y}Zi/zh  
// siteStop(); :k\} I k  
} <oQ6ZX  
!x6IV25  
Wy!uRzbBv  
System.err.println("文件下载结束!"); 03C .Xh=!  
} Z"]xdOre  
catch(Exception e){e.printStackTrace ();} c{ 7<H  
} !;jgzi?z  
5Vm Eyb  
4NJVW+:2  
//获得文件长度 ePi Z  
public long getFileSize() Agz=8=S%  
{ IE|, ~M2  
int nFileLength = -1; fmBkB8  
try{ >r~|1kQ.  
URL url = new URL(siteInfoBean.getSSiteURL()); y=wdR|b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E~}[+X@  
httpConnection.setRequestProperty("User-Agent","NetFox"); 16L"^EYq  
K1<k+t/V  
pA*i!.E/b  
int responseCode=httpConnection.getResponseCode(); |K6nOX!i  
if(responseCode>=400) ["<5?!bU  
{ *XHj)DC;  
processErrorCode(responseCode); \6Xn]S  
return -2; //-2 represent access is error M`(;>Kp7  
} {rz>^  
raSF3b/0  
K[n<+e;G  
String sHeader; \Ec X!aC  
~R)1nN|  
=1eV   
for(int i=1;;i++) ,=yOek}  
{ z_'dRw  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \G]K,TG  
//Utility.log(in.readLine()); bKTqX[=  
sHeader=httpConnection.getHeaderFieldKey(i); Sio1Q0  
if(sHeader!=null) ykJ+%gla  
{  z I(xSX@  
if(sHeader.equals("Content-Length")) 5[1@`6j   
{ ixg\[5.Q+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); n<=y"*  
break; x,}ez  
} w' .'Yu6  
} 2m|Eoc&M_  
else hjw4Xzju  
break; t2~"B&7My  
} /nwxuy  
} uwmoM>I W^  
catch(IOException e){e.printStackTrace ();} 6Q?BwD+>  
catch(Exception e){e.printStackTrace ();} :vw0r`  
cn@03&dAl  
c]S+70!n  
Utility.log(nFileLength); U<K|jsFo  
tWcizj;?wK  
^ sS>Mts  
return nFileLength; S_a :ML<  
} 8moUK3w  
?0? x+  
7ZL,p:f  
//保存下载信息(文件指针位置) !Jk(&.  
private void write_nPos() MiRibHXI,  
{ fLLnf].O  
try{ E {I)LdAqK  
output = new DataOutputStream(new FileOutputStream(tmpFile)); D1oaG0  
output.writeInt(nStartPos.length); od;Bb  
for(int i=0;i<nStartPos.length;i++) d&O'r[S  
{ 0~Um^q*'3  
// output.writeLong(nPos); [8 {_i?wY  
output.writeLong(fileSplitterFetch.nStartPos); Z83q-  
output.writeLong(fileSplitterFetch.nEndPos); 1'(_>S5CG  
} <)r,CiS  
output.close(); 0*/mc96  
} (xI)"{   
catch(IOException e){e.printStackTrace ();} <\B],M1=s=  
catch(Exception e){e.printStackTrace ();} z4 GN8:~x  
} AN|jFSQ'  
4he v ;  
Z&AHM &,yj  
//读取保存的下载信息(文件指针位置) Np|:dP9#}  
private void read_nPos() =>gyc;{2K<  
{ }IxY(`:qs  
try{ 7}.#Z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ho?|j"/7  
int nCount = input.readInt(); yBpW#1=  
nStartPos = new long[nCount]; $q4XcIX 7  
nEndPos = new long[nCount]; sURUQ  H  
for(int i=0;i<nStartPos.length;i++) c#]'#+aH  
{ j<`I\Pmv  
nStartPos = input.readLong(); p.6$w:eV  
nEndPos = input.readLong(); Y\ #.EVz  
} ;u4@iN}p  
input.close(); )^*9oqQ  
} .6lY*LI  
catch(IOException e){e.printStackTrace ();} $O;N/N:m  
catch(Exception e){e.printStackTrace ();} 0X ] ekq  
} T4%i`<i  
Xq=!"E  
1puEP *P  
private void processErrorCode(int nErrorCode) ;oN{I@}k  
{ jKY Aid{-  
System.err.println("Error Code : " + nErrorCode); L%c]%3A  
} 8:3oH!n  
9,Crmbw8  
@lb=-oR!~  
//停止文件下载 rCnV5Yb0O  
public void siteStop() d/ 'A\"o+  
{ D=5t=4^H(  
bStop = true; 3&drof\{  
for(int i=0;i<nStartPos.length;i++) g]EQ2g_N1  
fileSplitterFetch.splitterStop(); 6xDl=*&%  
EOd.Tyb!/  
*IMF4 x5M  
} >oM9~7f  
} a"v"n$  
//负责部分文件的抓取 y]~+`9  
**FileSplitterFetch.java |!jYv'%  
*/ HJ2]Nz:   
package NetFox; 'O\d<F.c$2  
H{Y5YTg]  
O+{pF.P#V  
import java.io.*; {2'74  
import java.net.*; j. ks UJ  
ims=-1,  
&vJ(P!2f<  
public class FileSplitterFetch extends Thread { fl5UY$a2-  
YW4b m  
_{2Fx[m%  
String sURL; //File URL 3isXgp8  
long nStartPos; //File Snippet Start Position wB1-|= K1  
long nEndPos; //File Snippet End Position bJG!)3cx  
int nThreadID; //Thread's ID b]tA2~e  
boolean bDownOver = false; //Downing is over n]6}yJJo  
boolean bStop = false; //Stop identical i 5 >J  
FileAccessI fileAccessI = null; //File Access interface E7Gi6w~\  
%>I?'y^  
c'TiWZP~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y*5@|Q  
{ 8;+Hou  
this.sURL = sURL; _!$Up  
this.nStartPos = nStart; Z;"4$@|qE  
this.nEndPos = nEnd; (DEL xE  
nThreadID = id; Pi"tQyw39$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \@ WsF$  
} NbQMWU~7  
rH2tC=%  
, $D&WH  
public void run() BRSgB-Rr7  
{ XEgx#F ;F  
while(nStartPos < nEndPos && !bStop) Im' :sJ31  
{ Z CQt1;  
J^F(]  
ga 2Q3mV  
try{ %1 VNP(E  
URL url = new URL(sURL); >zfZw"mEP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xi1N? pP  
httpConnection.setRequestProperty("User-Agent","NetFox"); -!bLMLIg  
String sProperty = "bytes="+nStartPos+"-"; b*6c. o  
httpConnection.setRequestProperty("RANGE",sProperty); 0Z1H6qn  
Utility.log(sProperty); "M5ro$qZ}  
U~){$kpI#  
c=jI.=mi3  
InputStream input = httpConnection.getInputStream(); 6b+ Wl Ib  
//logResponseHead(httpConnection);  Vgru, '  
_/z)&0DO  
_]?Dt%MkD  
byte[] b = new byte[1024]; G\,A> mT/P  
int nRead; uz#eO|z@o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;*37ta  
{ q_T?G e  
nStartPos += fileAccessI.write(b,0,nRead); {Y@-*pL]  
//if(nThreadID == 1) tmY-m,U  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .1[2 CjQ  
} hklO:,`  
nX.sh  
 z7.C\l  
Utility.log("Thread " + nThreadID + " is over!"); v{rK_jq  
bDownOver = true; MLv.v&@S  
//nPos = fileAccessI.write (b,0,nRead); VT.{[Kl  
}  8H%I|fm  
catch(Exception e){e.printStackTrace ();} d6d(? "  
} HA3SQ  
} C}8e<[} )  
Vf,~MG  
WT ~dA95  
//打印回应的头信息 hOrk^iYN=  
public void logResponseHead(HttpURLConnection con) + k(3+b$S-  
{ ) R a/  
for(int i=1;;i++) RwE*0 T  
{ OL ]T+6X  
String header=con.getHeaderFieldKey(i); )zL"r8si  
if(header!=null) XB!`*vZ/<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }r<@o3t  
Utility.log(header+" : "+con.getHeaderField(header)); [;V1y`/K1  
else Er)_[^) HG  
break; yY@ s(:  
} ,0<F3h  
} X?}GPA4 W  
$v bAcWj  
BqEubP(si  
public void splitterStop() <cfH '~  
{ J!K/7u S  
bStop = true; W1vAK  
} XpAq=p0;  
"TH-A6v1  
O"s`-OM;n  
} ^* /v,+01f  
3W0E6H"  
1~xn[acy  
/* { d2f)ra.  
**FileAccess.java |>o0d~s  
*//文件访问(定位,写) 6L6~IXL>  
package NetFox; -JQg ~1  
import java.io.*; }A'<?d8   
Hb AMoow!  
M_.,c Vk  
public class FileAccessI implements Serializable{ tU2to V  
8|-mzb&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,, H$>r_;  
RandomAccessFile oSavedFile; I}W-5%  
long nPos; KutgW#+40  
: $52Ds!i  
I9G*iu=U   
public FileAccessI() throws IOException /&!d  
{ ZEyGqCf3  
this("",0); R#Nd|f<  
} oQjB&0k4  
&_^*rD~  
@Jn:!8U0  
public FileAccessI(String sName,long nPos) throws IOException % x*Ec[l  
{ vyx\N{  
oSavedFile = new RandomAccessFile(sName,"rw"); 0qd;'r<  
this.nPos = nPos; $I6eHjYT  
oSavedFile.seek(nPos); io33+/  
} GqD!W8+  
Lvj5<4h;  
m<'xlF  
public synchronized int write(byte[] b,int nStart,int nLen) Md?bAMnG+}  
{ _kY[8e5  
int n = -1; dV=5_wXZ$  
try{ *I1W+W`G  
oSavedFile.write(b,nStart,nLen); e %v4,8  
n = nLen; UV8r&O  
} 8 W<)c  
catch(IOException e) &'ETx"  
{ QKaj4?p$|S  
e.printStackTrace (); ut5!2t$c  
} 6ewOZ,"j"4  
a&c#* 9t{  
[11-`v0  
return n; A%w]~ chC9  
} }:D~yEP  
Z a1|fB  
gsR9M%mv  
} y=qo-v59'  
n]fbV/ x  
]XafFr6pe  
/* DUliU8B}\  
**SiteInfoBean.java -r'seb5  
*/ ~S_IU">E  
package NetFox; &?Z)V-1H  
2GKU9cV*`  
-hR\Y 2?  
public class SiteInfoBean { ~q|e];tA  
<W%Z_d&Xv  
xv%USm  
private String sSiteURL; //Site's URL 95 .'t}  
private String sFilePath; //Saved File's Path 3XlnI:w =  
private String sFileName; //Saved File's Name MMr7,?,$  
private int nSplitter; //Count of Splited Downloading File hYv 6-5_  
<J }9.k  
yGG\[I;7  
public SiteInfoBean() v*fc5"3eO  
{//nSplitter的缺省值为5 ~_j%nJ &2  
//default value of nSplitter is 5 59Q Q_#>  
this("","","",5); 32|L $o  
} o3=S<|V  
N3c)ce7[  
}=m?gF%3  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jMWwu+w  
{ +U)|&1oa  
sSiteURL= sURL; ]9< 9F ?  
sFilePath = sPath; UpseU8Wo  
sFileName = sName; FRQ("6(  
this.nSplitter = nSpiltter; K}/`YDu  
WJ8vHPSM  
+Y]*>afG  
} g+r{>x  
BCZnF /Zo  
PZg]zz=V4  
public String getSSiteURL() Z*aU2Kr`;  
{ ` "":   
return sSiteURL; St&HE:  
} _v=WjN  
|b~g^4  
}J'w z;t1  
public void setSSiteURL(String value) y* Q-4_%,  
{ m1o65FsY08  
sSiteURL = value; ?[/,*Q%  
} ];~[Olc  
(0m$W<  
&`Z)5Ww  
public String getSFilePath() 8PjhvU  
{ UuC"-$:  
return sFilePath; 2OlC7X{  
} {!Z_&i5  
5N+(Gv[`"  
/~huTKA}  
public void setSFilePath(String value) LF.~rmPa  
{ HtYR 0J  
sFilePath = value; 4m!3P"$  
} cE>/iZc  
}e =GvWGa  
Pc4c Sw#5  
public String getSFileName() HFWm}vA:  
{ &:f'{>3z  
return sFileName; o? "@9O?  
} PlRs- %d  
Sz@?%PnU|  
H>X1(sh#}  
public void setSFileName(String value) 7t Kft  
{ sZBO_](S  
sFileName = value; g}r5ohqC#  
} 3^yWpSC  
Mf13@XEo  
K2`WcEe  
public int getNSplitter() <U`Nb) &  
{ tS|zf,7  
return nSplitter; ^l9 *h  
} jV&W[xKa  
E?D{/ k,zZ  
FGhrf  
public void setNSplitter(int nCount) 0M2+?aKif  
{ ]!o,S{a&  
nSplitter = nCount; 5<?$/H|7T  
} <f{`}drp/  
} Cy'W!qH  
[7w_.(f#  
&YP>" <  
/* k\Tm?^L)  
**Utility.java `9{C/qB  
*/ .h^Ld,Chj  
package NetFox; I19F\ L`4  
2czL 1Ci  
usf(U>  
public class Utility { -vAG5x/,  
!O_^Rn+<2  
>8t[EsW/  
public Utility() vg1s5Y qk  
{ _!1c.[ \T  
y+R$pzX  
#N}}8RL  
} z4:09!o_  
pvxqeC9`  
//线程睡眠 W?Abx  
public static void sleep(int nSecond) g c=|< (  
{ -3U} (cZ*  
try{ 7B"aFnK;[J  
Thread.sleep(nSecond); )WJI=jl  
} )3 ">%1R  
catch(Exception e) lfd{O7L0b  
{ Ap18qp  
e.printStackTrace (); [/j-d  
} |]b/5s;>  
} 8so}^2hTlT  
_Fy:3,(  
//日志 wb"t:(>&  
public static void log(String sMsg) {z ~ '  
{ Gfch|Q^INy  
System.err.println(sMsg); ~36XJ  
} uoc-qmm  
e}w!]  
fltc dA  
public static void log(int sMsg) ,1h(k<-  
{ c{ (%+  
System.err.println(sMsg); rn*VL(Yd(  
} <WkLwP3^  
} 4yy yXj  
MRu+:Y=K  
S@-X?Lu  
/* rVmO/Y#Hx$  
**TestMethod.java s7LX  
*/ P ^+>QJ1  
package NetFox; dU n#'<g5  
( h,F{7  
@},k\Is  
public class TestMethod { #2,L)E\G8e  
zxHfQ(  
NPabM(<`  
public TestMethod() X~!?t }  
{ ///xx/weblogic60b2_win.exe G&Sg .<hn  
try{ !\v3bOi&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `?m(Z6'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ` XY[ HK  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Hb4rpAeP  
fileFetch.start(); (b!DJ;(O9  
} ePdzQsnVe  
catch(Exception e){e.printStackTrace ();} k Er7,c  
:D-vE7  
u?/]"4  
} %&GQ]pmcY  
{.W%m  
V^5 t~)#46  
public static void main(String[] args) Cvy;O~)  
{ '.yr8  
new TestMethod(); #}?$mxME*  
} F@3,>~[%I  
} oaE3Aa  
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