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http断点续传简单实现(java)

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/* &InMI#0mV  
**SiteFileFetch.java $_P*Bk)  
*/ Gap\~Z@L  
package NetFox; 'Oe}Ja  
import java.io.*; "ccP,#Y  
import java.net.*; }N6r/ VtOQ  
d^Jf(NE0Yo  
Xw2tCRzD  
public class SiteFileFetch extends Thread { ,n &e,I  
B- VhUS  
qAF.i^  
SiteInfoBean siteInfoBean = null; //文件信息Bean b&$sY!iU  
long[] nStartPos; //开始位置 GG@&jcp7  
long[] nEndPos; //结束位置 h5.>};"@ '  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %+y92'GqG/  
long nFileLength; //文件长度 N))G/m3  
boolean bFirst = true; //是否第一次取文件 X+*"FKm S.  
boolean bStop = false; //停止标志 z&@Vg`w"  
File tmpFile; //文件下载的临时信息 uWSfr(loX  
DataOutputStream output; //输出到文件的输出流 /`j~r;S  
WF.y"{6>  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 9se ,c  
public SiteFileFetch(SiteInfoBean bean) throws IOException iq!u}# x_  
{ R3dCw:\O+Z  
siteInfoBean = bean; l]GUQcN=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v^;%Fz_Dr  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); oq>8  
if(tmpFile.exists ()) =n}+p>\s  
{ @]EJbiGv  
bFirst = false; re `B fN  
read_nPos(); Yc*Ex-s  
} 9Fkzt=(E~  
else u{-J?t&`  
{ y^SDt3Am  
nStartPos = new long[bean.getNSplitter()]; -0{"QhdE%  
nEndPos = new long[bean.getNSplitter()]; )^C w  
} 9Xu O\+z  
cTR@ :sm  
e uF@SS  
}4; \sY  
} A{!D7kwTz~  
K`25G_Y3@  
Zu$30&U  
public void run() wV9[Jl\Z  
{ iYyJq;S   
//获得文件长度 2[Ja|W\If  
//分割文件 16p$>a<6  
//实例FileSplitterFetch c%|18dV  
//启动FileSplitterFetch线程 /puM3ZN  
//等待子线程返回 L)sCc0fv7k  
try{ BAq@H8*B  
if(bFirst) 3+%c*}KC~  
{ "2}E ARa  
nFileLength = getFileSize(); RK*ZlD<  
if(nFileLength == -1) dh~+0FZ{A  
{ tWNz:V  
System.err.println("File Length is not known!"); C>?`1d@  
} Rr#vv  
else if(nFileLength == -2) wuv2bd )+  
{ %Q}T9%Mtj  
System.err.println("File is not access!"); <Q4yN!6  
} -qPYm?$  
else Dt9[uyP&  
{ azj:Hru&t#  
for(int i=0;i<nStartPos.length;i++) BtSl%(w  
{ c&+p{hH+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); X\I"%6$  
} QzwA*\G  
for(int i=0;i<nEndPos.length-1;i++) ~olta\|  
{ k-v@sb24_  
nEndPos = nStartPos[i+1]; em87`Hj^lo  
} 7,sslf2%K  
nEndPos[nEndPos.length-1] = nFileLength; FE)L?  
} (5SN=6O  
} B/(]AWi+  
M``I5r*cg  
eQ}o;vJN  
//启动子线程 Btmv{'T_y@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *}t,:N;i  
for(int i=0;i<nStartPos.length;i++) )1KlcF  
{ BCE} Er&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i#@3\&{J>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), v.08,P{b  
nStartPos,nEndPos,i); +$eEZ;4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Yxal%  
fileSplitterFetch.start(); xp395ub6  
} -`mHb  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8?lp:kM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); UqaLTdYG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %n3lm(-0U  
nEndPos = " + nFileLength); Lh%>> Ht{  
// fileSplitterFetch[nPos.length-1].start(); }*2q7K2bj  
z;dD }Fo  
#1:&uC1vj  
//等待子线程结束 PXZ ZPW/  
//int count = 0; d$uh .?F5  
//是否结束while循环 (f^K\7HM  
boolean breakWhile = false; ~*|0yPFg  
t?1+Yw./em  
Zd/ACZ[  
while(!bStop) cG|ihG5)  
{ MYzyg  
write_nPos(); .[v4'ww^  
Utility.sleep(500); ,8KD-"l^g  
breakWhile = true; 'V reO52  
H!y%FaTi  
zCdQI  
for(int i=0;i<nStartPos.length;i++) DK/xHIv8-  
{ +H[G D!  
if(!fileSplitterFetch.bDownOver) Nw`}iR0i  
{ cxhS*"Ph  
breakWhile = false; qwlIz/j  
break; 7|A9  
} D\~*| J  
} RcUKe,  
if(breakWhile) -q9`Btz  
break; `ySmzp  
C F2*W).+  
nVqFCBB  
//count++; -r9G5Z!|n  
//if(count>4) x0ZEVa0`4  
// siteStop(); F2 /-Wk@  
} Rc2|o.'y  
'CqWF"  
RCED K\*m  
System.err.println("文件下载结束!"); #tyHjk  
} U"} ml  
catch(Exception e){e.printStackTrace ();} #]ZOi`;  
} =='~g~  
VU1 ;ZJ E  
6vVx>hFJ47  
//获得文件长度 wl1JKiodg  
public long getFileSize() bgW=.s  
{ K)|#FRPM u  
int nFileLength = -1; 6{rH|Z  
try{ fqaysy  
URL url = new URL(siteInfoBean.getSSiteURL()); 5>J{JW|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s6k,'`.  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6~Y-bn"%D5  
"(uEcS2<  
hjB G`S#  
int responseCode=httpConnection.getResponseCode(); 4}:a"1P"  
if(responseCode>=400) o#X|4bES  
{ _ri1RK,  
processErrorCode(responseCode); Is~bA_- ;  
return -2; //-2 represent access is error F&r+"O)^-R  
} v3w5+F  
 -lM4*+f  
{'W\~GnZ  
String sHeader; *@J  
\29a@6  
6Sh0%F s  
for(int i=1;;i++) &j}\ZD  
{ qGtXReK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =;.#Bds  
//Utility.log(in.readLine()); `3!ERQU  
sHeader=httpConnection.getHeaderFieldKey(i); 9QaEUy*,  
if(sHeader!=null) #t /.fd  
{ {K-]nh/  
if(sHeader.equals("Content-Length")) d[+xLa  
{ [4:_6vd7X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jHPJk8@y  
break; #/'5N|?  
} )Yvf9dl  
} $ig%YB  
else . W{\wk n  
break; JV|GE n\@N  
} C<CE!|sfr  
} k$nQY  
catch(IOException e){e.printStackTrace ();} RsJj*REO  
catch(Exception e){e.printStackTrace ();} y0vo-)E]-]  
g2b %.X4  
0r=:l/Pz  
Utility.log(nFileLength); =:rR%L!a  
IS0RhtGy/  
~c7}eTJd"  
return nFileLength; S_cba(0-|\  
} MF/359r)Et  
1<_i7.{k  
<lh+mrXm  
//保存下载信息(文件指针位置) 24_F`" :-=  
private void write_nPos() g_Wf3o857J  
{ 8M m,a  
try{ S/CT;M@W  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "WOY`su>  
output.writeInt(nStartPos.length); Pb$ep|`u  
for(int i=0;i<nStartPos.length;i++) o.DT`L8  
{ -[?q?w!?  
// output.writeLong(nPos); ,o-BJ 069  
output.writeLong(fileSplitterFetch.nStartPos); H"W%+{AR  
output.writeLong(fileSplitterFetch.nEndPos); $FEG0&  
} CK1Xdyf_S  
output.close(); 6y&d\_?Y  
} '|n-w\ >Wv  
catch(IOException e){e.printStackTrace ();} Hw8`/'M=%5  
catch(Exception e){e.printStackTrace ();} cF_hU"  
} b'`8$;MII  
GuMsw*{>  
k WYjqv  
//读取保存的下载信息(文件指针位置) 2`,{IHu*!  
private void read_nPos() 0IoS|P}6a  
{ IH?.s k  
try{ F,^Q'$ !  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); HaI  
int nCount = input.readInt(); /C29^P  
nStartPos = new long[nCount]; IbAGnl{  
nEndPos = new long[nCount]; $-9m8}U(Y  
for(int i=0;i<nStartPos.length;i++) R?g qPi-  
{ qy6zHw  
nStartPos = input.readLong(); b`E'MX_ m  
nEndPos = input.readLong(); 3e$&rpv  
} g9OO#C>  
input.close(); HgY"nrogt$  
} dE2(PQb*P  
catch(IOException e){e.printStackTrace ();} X"<t3l(+  
catch(Exception e){e.printStackTrace ();} d V#h~  
} g]O"l?xx1D  
;bq_Y/"  
)6dvWK  
private void processErrorCode(int nErrorCode) %76N$`{u  
{ n\ aG@X%oq  
System.err.println("Error Code : " + nErrorCode); f,z_|e  
} }./__gJ  
9/ R|\  
S!o!NSn@1  
//停止文件下载 :WejY`}H%  
public void siteStop() O$+J{@  
{ {4tJT25  
bStop = true; [aX'eM q  
for(int i=0;i<nStartPos.length;i++) p%5RE%u  
fileSplitterFetch.splitterStop(); 3B95t-  
-%"Kxe  
_ v\=ag  
} MnUal}MO  
} -#= v~vE  
//负责部分文件的抓取 z>+@pj   
**FileSplitterFetch.java lil1$K: i  
*/ a%DnRkRr  
package NetFox; D]resk  
ZZp6@@zyq'  
I$v* SeVHE  
import java.io.*; 75}BI&t3k  
import java.net.*; Yd:8i JA  
fLl~a[(5  
ai[st+1  
public class FileSplitterFetch extends Thread { WP7*Q:5  
4Y8/>uL  
A?'Tigi  
String sURL; //File URL `yJpDGh  
long nStartPos; //File Snippet Start Position !]7r>NS>  
long nEndPos; //File Snippet End Position '"Q;54S**  
int nThreadID; //Thread's ID lw0l86^Y  
boolean bDownOver = false; //Downing is over IBr?6_\%"4  
boolean bStop = false; //Stop identical U#R=y:O?  
FileAccessI fileAccessI = null; //File Access interface ]Ow A>fb  
7:t+  
 6!])\Ay  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException d4F3!*@(  
{ J< BBM.^]  
this.sURL = sURL; b_@MoL@A!  
this.nStartPos = nStart; dM8`!~#&PI  
this.nEndPos = nEnd; w$4fS  
nThreadID = id; }7E2,A9_"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 GL'zs8AKf  
} !},_,J~(|  
0|n1O)>J  
0dA'f0Uy\X  
public void run() sI/Jhw)  
{ zl\mBSBx"  
while(nStartPos < nEndPos && !bStop) (gZKR2hO  
{ }6MHIr=o  
}$r/#F/Fn  
vL(7|K  
try{ J@w Q3#5a  
URL url = new URL(sURL); eS9uKb5n(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ` WIv|S  
httpConnection.setRequestProperty("User-Agent","NetFox"); }8Tr M0q8  
String sProperty = "bytes="+nStartPos+"-"; &wr0HrE\  
httpConnection.setRequestProperty("RANGE",sProperty); ^@e4m O  
Utility.log(sProperty); s0 hD;`cm  
v<N7o8  
I5PI;t+  
InputStream input = httpConnection.getInputStream(); ZG>I[V'p=  
//logResponseHead(httpConnection); E$dPu  
VeidB!GyP  
cLn&b}8'  
byte[] b = new byte[1024]; IY2ca Xu  
int nRead;  +T02AS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^=@L(;Y  
{ 0@ []l{N  
nStartPos += fileAccessI.write(b,0,nRead); oA`'~~!  
//if(nThreadID == 1) ys|a ^VnN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <z+5+h|^  
} ).e_iE[&  
\?A 7{IY  
XOK.E&eilj  
Utility.log("Thread " + nThreadID + " is over!"); Q[J%  
bDownOver = true; F[mL_JU  
//nPos = fileAccessI.write (b,0,nRead); e>\[OwF-x  
} uuW._$.A>  
catch(Exception e){e.printStackTrace ();} `+cc{k  
} 0w}OE8uq  
} :G\f(2@  
n!e4"|4~z  
hOjy$Z  
//打印回应的头信息 yUcWX bT@  
public void logResponseHead(HttpURLConnection con) P 0v&*y3Y  
{ y6tzmyg  
for(int i=1;;i++) _Vr>/f  
{ &|'k)6Rx  
String header=con.getHeaderFieldKey(i); qg6283'?  
if(header!=null) ousvsP%'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /ghXI"ChI  
Utility.log(header+" : "+con.getHeaderField(header)); +HvEiY  
else ^6tGj+D9  
break; :=!?W^J  
} jy#'oadS?  
} z)N8#Y~vn  
|9c J O@  
}_m/3*x_  
public void splitterStop() ]G m"U!h*  
{ ^y"5pf SR  
bStop = true; @%mJw u  
} Oo<L~7B  
X,dOF=OJL  
iX,| ;J|]  
} v.Wkz9 w}  
seO7/h_a  
KLi&T mIB  
/* YJi C}.4Q  
**FileAccess.java ]/>(C76  
*//文件访问(定位,写) i Qs7L y"  
package NetFox; #5*|/LD  
import java.io.*; @X\-c2=  
SJ4[n.tPI  
Q@zD'G >  
public class FileAccessI implements Serializable{ ;s m )f  
ZdQt!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <pzCpF<  
RandomAccessFile oSavedFile; /, T@/  
long nPos; uR#aO''  
@}sxA9 a  
eiE36+'>b  
public FileAccessI() throws IOException 3Q'Q %2  
{ Te&F2`vo  
this("",0); fHK`u'  
} #qqIOjS^w  
I6!~(ND7  
?86q8E3;&  
public FileAccessI(String sName,long nPos) throws IOException A"Q6GM2;Io  
{ LDilrG)  
oSavedFile = new RandomAccessFile(sName,"rw"); h8#14?  
this.nPos = nPos; ft$@':F  
oSavedFile.seek(nPos); @,btQ_'X  
} oNW5/W2e;  
X.^S@3[  
R0|dKKzS  
public synchronized int write(byte[] b,int nStart,int nLen) h$3o]~t  
{ 1yHlBeEC  
int n = -1;  {*!L[)  
try{ V}c3}'_U]  
oSavedFile.write(b,nStart,nLen); d~#>.$Uu  
n = nLen; w Q!C9Gp3e  
} 9p| ;Hh:  
catch(IOException e) Z{<&2*  
{ IpX.ube  
e.printStackTrace (); y>4r<Y ZQ  
} ;Ih:$"$!  
PtP{_9%Dz  
2Fwp\I;  
return n; NF9fPAF%;  
} [=f(u wY>g  
O"%b@$p\L  
vRp#bScc  
} xw[KP [(  
4}C^s\?z  
,|:TML  
/* `v;9!ReZV  
**SiteInfoBean.java ,ddoII  
*/ ;h|zNx0  
package NetFox; !h\>[O  
6k569c{7  
v D"4aw  
public class SiteInfoBean { RRXnj#<g  
cOz8YVR-  
yDmNPk/  
private String sSiteURL; //Site's URL `XT8}9z!  
private String sFilePath; //Saved File's Path ANqWY &f  
private String sFileName; //Saved File's Name 5%`fh%  
private int nSplitter; //Count of Splited Downloading File =~qQ?;o n  
.x6c.Y.S  
#J4{W84B  
public SiteInfoBean() j6Msbq[  
{//nSplitter的缺省值为5 #kho[`9  
//default value of nSplitter is 5 o|r8x_!+  
this("","","",5); gzV&S5A{_  
} xLZJ[:gr  
kBF.TGT[l  
/#WRd}IjK  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) a| w.G "W  
{ W8bh49   
sSiteURL= sURL; Vr%>'XN>"  
sFilePath = sPath; hDPZj#(c  
sFileName = sName; >"Tivc5  
this.nSplitter = nSpiltter; -L zx3"  
tsGt,]O30  
qe M`z  
} l:' 0  
,q[aV 6kO  
\&tv *  
public String getSSiteURL() c4\Nuy  
{ abs\Ku9  
return sSiteURL; H@-txO1`::  
} g3fxf(iY(  
no~Yet+<"  
6A$  Y]u  
public void setSSiteURL(String value) jFE1k(2e  
{ {DP%=4  
sSiteURL = value; c;RL<83:  
} YTb/ LeuT  
S5%I+G3  
3vcKK;qCB  
public String getSFilePath() ]x;*Z&  
{ =I(F(AE  
return sFilePath; yUUg8xbpxF  
} |IN{8  
IF>dsAAI<  
*F4"mr|\  
public void setSFilePath(String value) yX`5x^wVw  
{ @ OSSqH  
sFilePath = value; wWh)yfPh8H  
} htgtgW9 ^P  
M/Twtq-`H  
ON.1'Wk?  
public String getSFileName() !L|}/u3v  
{ lla?;^,  
return sFileName; LtJl\m.th  
} bi01]  
#L3heb&9  
obRYU|T  
public void setSFileName(String value) W{)RJ1  
{ =qg;K'M5  
sFileName = value; ?.*^#>-  
} 84X/=l-c=  
&"_5?7_N  
{jK:hQX  
public int getNSplitter() c3L)!]kB  
{ @2X{e7+D  
return nSplitter; o+}>E31a  
} o.o$dg(r!  
w6Owfq'v  
>14 x.c  
public void setNSplitter(int nCount) }{oZdO  
{ xJNV^u  
nSplitter = nCount; @Yu=65h  
} >GV(\In  
} )qq5WShMJ  
NKyKsu  
3EVAB0/$  
/* F{'lF^Dc  
**Utility.java mdNIC  
*/ $FJf8u`  
package NetFox; X~o6Xkg  
ntZl(]l  
A.8[FkiNmD  
public class Utility { NUQ?Q Q  
w4<n=k  
F5+)=P#  
public Utility() 3$~oQC  
{ uXm_ pQpF  
A0A]#=S  
zP`&X:8  
} H,Y+n)5  
7_ G$&  
//线程睡眠 5Z<y||=  
public static void sleep(int nSecond) E3~Wyfd7  
{ NB.s2I7  
try{ qhQeQ  
Thread.sleep(nSecond); Zr#\>h'c  
} &BZjQK  
catch(Exception e) UG,<\k&  
{ 0rA&Q0  
e.printStackTrace (); zHg1K,t:  
} qOD:+b  
} C25EIIdRb  
vMHJgpd&j  
//日志 sI OT6L^7  
public static void log(String sMsg) X$0&tmum  
{ D=^|6}  
System.err.println(sMsg); i^Ip+J+[  
} kp=wz0#  
"BvAiT{u  
2zlBrjk;  
public static void log(int sMsg) N ,0&xg3  
{ ,| Zkpn8  
System.err.println(sMsg); !zR1CM  
} 1:j[p=Q&  
} VX+:C(m~  
b9L" ?{  
9l&4mt;+&<  
/* I$Ra*r  
**TestMethod.java SKdh!*G  
*/ c*N>7IF,  
package NetFox; XPfheV G  
H3Zs m)+:  
J};=)xLX;  
public class TestMethod { Fs 95^T  
;%YAiW8{Xk  
(DTXc2)c  
public TestMethod() z<jH{AU  
{ ///xx/weblogic60b2_win.exe lWRRB&8  
try{ F4|U\,g  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); U^~jB= =]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N_Q\+x}zq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \ 0J &^C  
fileFetch.start(); 8Rric[v  
} ?Mj@;O9>'  
catch(Exception e){e.printStackTrace ();} .ZVADVg\  
SMMvRF`7  
)ePQN~#K}  
} lG/h[  
d>-k-X-[  
0)HZ5^J  
public static void main(String[] args) L^%jR=  
{ cd3;uB4\,  
new TestMethod(); ZGgM- O1  
} L; (J6p]h  
} T*bBw  
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