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http断点续传简单实现(java)

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/* m8AAp1=  
**SiteFileFetch.java Xm@aYNV  
*/ u]bz42]  
package NetFox; ET+'Pj3  
import java.io.*; Rsn^eR6^  
import java.net.*; _-TOeP8#94  
HH zEQV Lh  
8Zw]f-5x\  
public class SiteFileFetch extends Thread { !FP"M+  
(OqHfv  
afUTAP@  
SiteInfoBean siteInfoBean = null; //文件信息Bean @ef$b?wg  
long[] nStartPos; //开始位置 Nb1J ~v  
long[] nEndPos; //结束位置 4By]vd<;=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 j+Zt.KXjT  
long nFileLength; //文件长度 ?gG,t4D  
boolean bFirst = true; //是否第一次取文件 +?V0:Kz]  
boolean bStop = false; //停止标志 pl\b-  
File tmpFile; //文件下载的临时信息 y ||@?Y  
DataOutputStream output; //输出到文件的输出流 t'aSF{%  
w_3xKnMT\  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) tBv3~Of.  
public SiteFileFetch(SiteInfoBean bean) throws IOException D'n7&Y  
{ ~S;!T  
siteInfoBean = bean; !0Nf9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =GTD"*vwr  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ; 8E;  
if(tmpFile.exists ()) :'Xr/| s  
{ <m1sSghg  
bFirst = false; n;qz^HXEJ  
read_nPos(); a2X h>{  
} 5[<F_"x  
else N8 M'0i?  
{ ;dOs0/UM&  
nStartPos = new long[bean.getNSplitter()]; Y }/c N\  
nEndPos = new long[bean.getNSplitter()]; =)*JbwQ   
} ]>vf9]  
hHEPNR[.  
z5pc3:  
E*^ 9|Y[  
} (H1lqlVWV#  
2Y;!$0_rv  
J | q^+K  
public void run() L~ 2q1  
{ gLx/w\l6  
//获得文件长度 cUsL 6y  
//分割文件 [?I/Uo8  
//实例FileSplitterFetch C Oa.xyp  
//启动FileSplitterFetch线程 |lE-&a$xd  
//等待子线程返回 Wxs>osq  
try{ FF3&Y^+^"  
if(bFirst) Gql`>~  
{ &N9IcNP  
nFileLength = getFileSize(); [9HYO  
if(nFileLength == -1) 8H_l[/  
{ 6W:1>,xS  
System.err.println("File Length is not known!"); Q ]0r:i= .  
} 5y}BCY2=/  
else if(nFileLength == -2) W\NG>t  
{ ke^d8Z.  
System.err.println("File is not access!"); h(|;\~  
} (,U7 R^  
else @ge LW!  
{ zu C5@jy.x  
for(int i=0;i<nStartPos.length;i++) #EFMgQO  
{ AygvJeM_W  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3u4:l  
} dxntGH< O  
for(int i=0;i<nEndPos.length-1;i++) V $>"f(  
{ ~hzEKvs  
nEndPos = nStartPos[i+1]; q^%5HeV 2  
} q#|r   
nEndPos[nEndPos.length-1] = nFileLength; %:%MUdl6  
} cPJ7E  
} pW7kj&a_.  
(Wn "3 ]  
?l>e75V%w  
//启动子线程 wM0E%6 P  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Bqp&2zg)@  
for(int i=0;i<nStartPos.length;i++) boIVU`F-!  
{ g*28L[Q~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BPqwDj W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I0(8Z]x  
nStartPos,nEndPos,i); C?S~L5a#oC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (c<f<D|  
fileSplitterFetch.start(); HI z9s4Y_  
} M",];h(I6(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y6+k9$h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PJ}[D.elO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tfsh!)u?  
nEndPos = " + nFileLength); tgc@7  
// fileSplitterFetch[nPos.length-1].start(); wD}EW  
4sI3(z)9H  
L+uOBW_  
//等待子线程结束 5vYsA1Z  
//int count = 0; +B](5z4  
//是否结束while循环 jzQ9zy_  
boolean breakWhile = false;  KzIt  
$,g 3*A  
8Er[M  
while(!bStop) F>TYVxQ  
{ 7L1\1E:!  
write_nPos(); 2Qw )-EB  
Utility.sleep(500); xcsFODx~  
breakWhile = true; H7y&N5.V  
:jl u  
5f/@: ~  
for(int i=0;i<nStartPos.length;i++) |:dCVd<du  
{ 3x,Aczb  
if(!fileSplitterFetch.bDownOver) "9TxK6  
{ =%:JjgKc*t  
breakWhile = false; :v|r=#OI  
break; $:xF)E  
} XB6N[E  
} XCKY xv&  
if(breakWhile) *pDXcURw  
break; V]+o)A$  
^A:!ni@3  
GZxglU,3T  
//count++; Sn_z  
//if(count>4) ~ra#UG\Y8  
// siteStop(); e);bF>.~  
} zpBBnlq  
2&zn^\%"  
=1V>Vd?8.  
System.err.println("文件下载结束!"); uzat."`d'  
} Lf$Q %eM0  
catch(Exception e){e.printStackTrace ();} R^mu%dw)(%  
} ,%"\\#3S  
BH.:_Qrbh[  
k~'?"'  
//获得文件长度 z7NGpA(  
public long getFileSize() PV5TG39qQ  
{ * K0j5dx  
int nFileLength = -1; #QJ4o_  
try{ X_^_r{  
URL url = new URL(siteInfoBean.getSSiteURL()); F&nMI:h7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FJ3:}r6 "  
httpConnection.setRequestProperty("User-Agent","NetFox"); #`YxoY`  
[[.&,6  
KxgR5#:i"  
int responseCode=httpConnection.getResponseCode(); 6T} CPDRq  
if(responseCode>=400) Y_|K,T6Zj@  
{ A~yw8v5UF  
processErrorCode(responseCode); TnMVHO-  
return -2; //-2 represent access is error s)`1Rf  
} #%} u8\q  
]HZa:aPY  
f:JYG]E&  
String sHeader; g-{<v4NGI  
.zSimEOF  
%BKR}  
for(int i=1;;i++) K{r1&O>W  
{ l9ch  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ztpm_P6  
//Utility.log(in.readLine()); {C,1w  
sHeader=httpConnection.getHeaderFieldKey(i); U{za m  
if(sHeader!=null) twJ|Jmd  
{ [M8qU$&?]  
if(sHeader.equals("Content-Length")) e{rHO,#A>  
{ y9re17{ X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); wr;|\<c  
break; Ep,0Z*j  
} x" :Bw;~  
} GqK&'c   
else ,N@Icl  
break; e$xv[9  
} wEHrer  
} }:c,S O!  
catch(IOException e){e.printStackTrace ();} ;]#4p8lh+  
catch(Exception e){e.printStackTrace ();} .KwuhmR  
lo]B 5_en  
p?`|CE@h7  
Utility.log(nFileLength); $=QGua V  
uI:3$  
2Ws/0c  
return nFileLength; s2' :&5(  
} |uBot#K|  
 KHs{/  
 ~bWWu`h  
//保存下载信息(文件指针位置) \q d)l  
private void write_nPos() Tdmo'"m8z_  
{ (.nJT"&  
try{ +Tc(z{;  
output = new DataOutputStream(new FileOutputStream(tmpFile));  rgvc5p  
output.writeInt(nStartPos.length); ?[4khQt  
for(int i=0;i<nStartPos.length;i++) vJj j+:  
{ #O974f8  
// output.writeLong(nPos); ^{sI'l~  
output.writeLong(fileSplitterFetch.nStartPos); fdEj#Ux<H  
output.writeLong(fileSplitterFetch.nEndPos); K|J#/  
} &7kSLat+9{  
output.close(); rJ~(Xu>,s  
} HE<%d  
catch(IOException e){e.printStackTrace ();} :tDGNz*zG  
catch(Exception e){e.printStackTrace ();} )mZy>45  
} bDh(;%=  
cXE y>U|/  
!I+u/f?TO7  
//读取保存的下载信息(文件指针位置) g$+O<a@n  
private void read_nPos() cFNtY~(b  
{ (8X8<>w~  
try{ S5 oHe4#89  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); l:C0:m%  
int nCount = input.readInt(); !-o||rt  
nStartPos = new long[nCount]; R =c  
nEndPos = new long[nCount]; +fR`@HI  
for(int i=0;i<nStartPos.length;i++) ]vyF&`phb  
{ 8jx1W9=`9[  
nStartPos = input.readLong(); 6%y: hLT  
nEndPos = input.readLong(); 6>A8#VT  
} ];]EK6dzG  
input.close(); iB_j*mX]  
} m 1;jS|  
catch(IOException e){e.printStackTrace ();} }7v2GfEkM  
catch(Exception e){e.printStackTrace ();} a5&j=3)|  
} E6)mBAE  
Sw)ftC~d  
FZ/&[;E!  
private void processErrorCode(int nErrorCode) @/iLC6QF  
{ ylJlICK  
System.err.println("Error Code : " + nErrorCode); |7fBiVo  
} u'> CU  
t,6=EK*3T  
giq`L1<  
//停止文件下载 K.7gd1I  
public void siteStop() jm"xf7  
{ "de:plMofy  
bStop = true; O}V2> W$  
for(int i=0;i<nStartPos.length;i++) B~rK3BS  
fileSplitterFetch.splitterStop(); P&;I]2#  
Hua8/:![+  
Ek0.r)Nw  
} M}u2aW2]X  
} <^paRKEa+#  
//负责部分文件的抓取 tA.C"  
**FileSplitterFetch.java t!GY>u>`  
*/ #oI`j q  
package NetFox; |zE7W  
*XuzTGa"  
cW\7yZh  
import java.io.*; *:(t.iL  
import java.net.*; lk|/N^8M  
L<n_}ucA  
uJizR F  
public class FileSplitterFetch extends Thread { j#,O,\  
e_SlM=_ u  
l_WY];a  
String sURL; //File URL $8)/4P?OL  
long nStartPos; //File Snippet Start Position }V{, kK  
long nEndPos; //File Snippet End Position 'J}lnt[V  
int nThreadID; //Thread's ID `{%*DHa  
boolean bDownOver = false; //Downing is over We|*s2!  
boolean bStop = false; //Stop identical yd k  
FileAccessI fileAccessI = null; //File Access interface PNq#o%q  
Kmtr.]Nj  
1EN5ZN,  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException I`|>'$E[r  
{ zI(Pti  
this.sURL = sURL; T!n<ya!  
this.nStartPos = nStart; `&o|=  
this.nEndPos = nEnd; =vWnqF:  
nThreadID = id; 2 Ug jH  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *+G K ?Ga  
} qQb8K+t  
W$y?~2  
uo0(W3Q *  
public void run() +CACs7tV  
{ Y9Pb  
while(nStartPos < nEndPos && !bStop) |D\ ukml  
{ 4 P.ry|2  
(mzyA%;W  
2iUF%>  
try{ ,yC~{ H  
URL url = new URL(sURL); wL{Qni3A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pG (8VteH  
httpConnection.setRequestProperty("User-Agent","NetFox"); FIuKX"XR  
String sProperty = "bytes="+nStartPos+"-"; V; ChrmE  
httpConnection.setRequestProperty("RANGE",sProperty); ^t| %!r G  
Utility.log(sProperty); 9O|m# &wa]  
b_B4  
v>,XJ7P  
InputStream input = httpConnection.getInputStream(); \d6A<(!=v  
//logResponseHead(httpConnection); u}pLO9V"`  
A;% fAI2Vr  
F:n7yey  
byte[] b = new byte[1024]; 2 nf{2edC  
int nRead; $(GXlhA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B${Q Y)t  
{ a{y ;Ub  
nStartPos += fileAccessI.write(b,0,nRead); gG#M-2P  
//if(nThreadID == 1) ?O28Q DUI  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FvRog<3X  
} Cjw|.c`  
wE'~Qj  
EayZ*e ]  
Utility.log("Thread " + nThreadID + " is over!"); IF<jq\M  
bDownOver = true; Wu:evaZ:i  
//nPos = fileAccessI.write (b,0,nRead); %kF6y_h`  
} 0PZpE "$X  
catch(Exception e){e.printStackTrace ();} Nl0*"}`I_  
} Z/O5Dear/h  
} T$SGf.-  
`Os@/S  
-_B*~M/vV`  
//打印回应的头信息 <"6 }C)G  
public void logResponseHead(HttpURLConnection con) K1jE_]@Z  
{ GP1b/n3F1  
for(int i=1;;i++) ^`ny]3JA  
{ 1a`dB ~>  
String header=con.getHeaderFieldKey(i); n%A)#AGGc  
if(header!=null) wgY: W:y'N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ym^  
Utility.log(header+" : "+con.getHeaderField(header)); L2+~I<|>  
else i ,ga2{GnM  
break; R e-4y5f  
} 'V/+v#V+>  
} xO{yr[x"L  
]U82A**n  
T:dV[3  
public void splitterStop() cJ=0zEv  
{ F@UbUm2o  
bStop = true; D&#wn.0|E  
} OF-$*  
yJNQO'wcv  
@#rF8;  
} Y'H|Tk^`  
G*^4+^Vz?  
H85J MPZ7  
/* NSI$uS6  
**FileAccess.java n 'gU  
*//文件访问(定位,写) 4d-f 6iiFV  
package NetFox; (l}W\iB' d  
import java.io.*; 7Ji|x{``  
8#L V oR  
m9M#)<@*  
public class FileAccessI implements Serializable{ d;@"Naw  
?h\fwF3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =S#9\W&6Q  
RandomAccessFile oSavedFile; P.aN4 9`=  
long nPos; ma TQ 0GX  
"lLwgh;  
x18(}4  
public FileAccessI() throws IOException Gu@n1/m@o  
{ LT[g +zGB  
this("",0); [3D*DyQt  
} z;iNfs0i$  
!:baG]Y  
_TntZv.?  
public FileAccessI(String sName,long nPos) throws IOException '9u(9S  
{ z_f^L %J0  
oSavedFile = new RandomAccessFile(sName,"rw"); hU'h78bt(  
this.nPos = nPos; uo9FLm  
oSavedFile.seek(nPos); Zz/ z7~{  
} {^":^N)  
>)^Q p-  
T {:8,CiW  
public synchronized int write(byte[] b,int nStart,int nLen) #?"^:,Y  
{ []:&WA 9N  
int n = -1; LIE5of  
try{ 7y4jk  
oSavedFile.write(b,nStart,nLen); l=UXikx  
n = nLen; nD.K*#u  
} 8'qq!WR~  
catch(IOException e) y**YFQ*sc  
{ %/oeV;D  
e.printStackTrace (); IFsh"i  
} p(>D5uN_}5  
fG zx;<0P!  
 qC6@  
return n; jP#I](\eG  
} ^P|Zze zwU  
BD- c<K"  
V3Ep&<=/  
} 4&AGVplgF  
9zl-C*9vj  
bgeJVI  
/* O{x-9p  
**SiteInfoBean.java ~p?D[]h  
*/ L8J] X7  
package NetFox; ;#L]7ZY9:-  
D@%!|:  
QtA@p  
public class SiteInfoBean { &z05h<]  
 Q!5W x  
_ h/:r1  
private String sSiteURL; //Site's URL 87F]a3  
private String sFilePath; //Saved File's Path G\R6=K:f7  
private String sFileName; //Saved File's Name T|p%4hH  
private int nSplitter; //Count of Splited Downloading File @=OX7zq\h-  
dVMLn4[,MA  
+7{8T{  
public SiteInfoBean() @~&|BvK% \  
{//nSplitter的缺省值为5 'U,\5jj'Y  
//default value of nSplitter is 5 /IlO   
this("","","",5); Y.q$"lm7k  
} OepQ Z|2  
 PZY6 I  
K#Xl)h}y7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .e4upT GU  
{ ,Iru_=Wk~  
sSiteURL= sURL; ^A=2#j~H\  
sFilePath = sPath; 9rIv-&7'm  
sFileName = sName;  /i   
this.nSplitter = nSpiltter; PzT@q\O  
MwX8FYF D  
V+zn` \a  
} _;R#B`9Iu  
Q3'P<"u  
8K@e8p( y  
public String getSSiteURL() 3[@:I^q  
{ E B! ,t  
return sSiteURL; TEbIU8{Y  
} YV'B*arIA  
b~{nS,_Rn  
-c{Y+M`  
public void setSSiteURL(String value) [+ : zlA  
{ >QPCYo<E  
sSiteURL = value; X5(oL  
} (=j/"Mb  
,Xg^rV~]  
-0I&dG-  
public String getSFilePath() Y5P9z{X=  
{ It VVI"-  
return sFilePath; f%JM a]yV  
}  ~fs} J  
6W~JM^F  
:;IZ|hU  
public void setSFilePath(String value) 1(Z+n,Hh  
{ _n4_;0  
sFilePath = value; C' WX$!$d  
} MwL!2r  
-=n!k^?lK  
Rl_1g`84  
public String getSFileName() "`mG_qHI[  
{ P)~olrf  
return sFileName; O&#>i]*V  
} QWWI  
N/1xc1$SB  
V2:S 9vO'  
public void setSFileName(String value) fo <nk|i  
{ jw/@]f;N  
sFileName = value; K M[&WT  
} DcC|oU[  
#Fgybokm  
gt=@v())  
public int getNSplitter() 5A%Uv*  
{ FTzc,6  
return nSplitter; F^lau f  
} Zrew}0  
\5a;_N[Ed  
"|N0oEG&  
public void setNSplitter(int nCount) i3) 7Qa[  
{ bU}l*"  
nSplitter = nCount; S2 P9C"  
} bn=7$Ax  
} X|4Kdi.r@  
J/rF4=j%xy  
B-|C%~fe  
/* g>a% gVly  
**Utility.java ACI.{`SrQ=  
*/ zs'Jgm.v  
package NetFox; 6I|9@~!y[  
d_ &~^*>  
$dKo}  
public class Utility { gRw? <U^  
[t*-s1cq  
Wi*HLP!lNC  
public Utility()  Sg(\+j=  
{ {>Qs+]  
vCtnjWGX}/  
1R]h>'  
} "rrE_  
I@1VX5  
//线程睡眠 !$Arc^7r  
public static void sleep(int nSecond) T+:GYab/  
{ /~g.j1g  
try{ +('=Ryo T  
Thread.sleep(nSecond); g{hbq[>X]  
} #*  8^ar<  
catch(Exception e) .|y{1?f_  
{ NRs%q}lX  
e.printStackTrace (); cdg &)  
} =05jjR1  
} Nu><r  
\~T&C5  
//日志 f/Q/[2t  
public static void log(String sMsg) p0pA|  
{ KPa@~rU  
System.err.println(sMsg); raZ0B,;eFu  
} T 6=~vOzTJ  
GJBMaT  
>NA{**$0  
public static void log(int sMsg) WAVEwA`r  
{ ASr3P5/  
System.err.println(sMsg); %;O# y3,  
} {<2q  
} w)}@svv"  
-M-y*P)  
rU7t~DKS  
/* B(pHo&ox  
**TestMethod.java I! ~3xZ  
*/ XK yW  
package NetFox; :;o?d&C  
w)Y}hlcq  
L$; gf_L  
public class TestMethod { WZ ,t~TN  
w M#q [m;  
Xgo`XsA  
public TestMethod() C,5Erb/  
{ ///xx/weblogic60b2_win.exe jq+:&8!8(e  
try{ l4q7,%G  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w%f51Ex  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6X$iTJ[\x  
SiteFileFetch fileFetch = new SiteFileFetch(bean); '59l.  
fileFetch.start(); 3$kElq[  
} ~;nW+S$o  
catch(Exception e){e.printStackTrace ();} 9S)A6]  
E=~Ahkg  
SrXuiiK  
} 9!Vp-bo  
~Nl`Zmn(A|  
@#| R{5=+  
public static void main(String[] args) Rj,M|9Y)o  
{ n`7n5M*  
new TestMethod(); Mer\W6e"e  
} /4u:5G  
} w7h=vy n?  
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