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http断点续传简单实现(java)

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/* zcZ^s v>  
**SiteFileFetch.java Wl?<c uw00  
*/ Mru~<:9  
package NetFox; EyzY2>"^  
import java.io.*; }&=uZ:  
import java.net.*; T<_+3kw  
&KLvr|  
;,R[]B01u  
public class SiteFileFetch extends Thread { E=3#TBd  
\?[O,A  
&(GopWR`e  
SiteInfoBean siteInfoBean = null; //文件信息Bean 8 `yB  
long[] nStartPos; //开始位置 v)TUg0U=,  
long[] nEndPos; //结束位置  $.=5e3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &C\=!r0j^  
long nFileLength; //文件长度 +~@7" |d  
boolean bFirst = true; //是否第一次取文件 tYF$#Nor#k  
boolean bStop = false; //停止标志 EwC5[bRjUp  
File tmpFile; //文件下载的临时信息 ?#x'_2  
DataOutputStream output; //输出到文件的输出流 N" 8*FiZ|  
F1zT )wW  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 3@%BA(M  
public SiteFileFetch(SiteInfoBean bean) throws IOException pFG]IM7o/u  
{ 1mAUEQ!  
siteInfoBean = bean; Al)lWD}j2g  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5Gc_LI&v7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F%9e@{  
if(tmpFile.exists ()) lrq>TJEcx  
{ (q0No26;(  
bFirst = false; 7O]J^H+7  
read_nPos(); "Wxo[I  
} 7cy+Nz  
else Fa6H(L3  
{ 6oPUYn-  
nStartPos = new long[bean.getNSplitter()]; ^f!Zr  
nEndPos = new long[bean.getNSplitter()]; 8Ix -i  
} $b&BH'*'~  
,M| QN*  
EolE?g@l8  
B!$V\Gs  
}  >cC Gx  
+qE,<c}}  
,ZsYXW  
public void run() = E##},N"  
{ L.R"~3  
//获得文件长度 mYzsT Uq  
//分割文件 oUnq"]  
//实例FileSplitterFetch -Y5YCY!`  
//启动FileSplitterFetch线程 W9:fKP  
//等待子线程返回 $K5ni{M;  
try{ 7[(Lrx.pM  
if(bFirst) i7Y s_8A"9  
{ BXagSenc  
nFileLength = getFileSize(); gK&5HTo  
if(nFileLength == -1) %g2/ o^c*  
{ J r=REa0  
System.err.println("File Length is not known!"); oHv{Y  
} ZJiuj!  
else if(nFileLength == -2) $`-SVC  
{ yBU ZVqqDa  
System.err.println("File is not access!"); r@N39O*Wq  
} Q"x`+?!  
else L{+&z7M  
{ &ryl$!!3H  
for(int i=0;i<nStartPos.length;i++) oAIY=z  
{ *93l${'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &<\4q  
} IBn'iE[>  
for(int i=0;i<nEndPos.length-1;i++) TyxU6<>4J4  
{ !Qj)tS#Az  
nEndPos = nStartPos[i+1]; &;SwLDF"1  
} m70`{-O  
nEndPos[nEndPos.length-1] = nFileLength; s{x*~M$vt  
} yf0vR%,\  
} 5i}CzA96  
N>W;0u!  
7C,<iY  
//启动子线程 #`fi2K&]j  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0:7v/S!:  
for(int i=0;i<nStartPos.length;i++) `8$:F4%P  
{ r&H=i  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IG2`9rR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  60Xl.  
nStartPos,nEndPos,i); [qO5~E`;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tal>b]B;  
fileSplitterFetch.start(); $9LGdKZ_D  
} B;Q`vKY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f }evw K[S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); F:[Nw#gj/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %RfY`n  
nEndPos = " + nFileLength); o>/uW8  
// fileSplitterFetch[nPos.length-1].start(); s= -WB0E  
1[fkXO{  
1 Ovx$ *  
//等待子线程结束 KNO*)\   
//int count = 0; op.PS{_t  
//是否结束while循环 s K""  
boolean breakWhile = false; 'PmHBQvt&  
tS_xa  
bv:0EdVr  
while(!bStop) Xy3g(x]  
{ Y%n{`9=  
write_nPos(); T6/$pJl  
Utility.sleep(500); !>a&`j2:W  
breakWhile = true;  8o%<.]   
df21t^0/  
t ?Njw7  
for(int i=0;i<nStartPos.length;i++) *Dd(+NI  
{ y4)ZUv,}  
if(!fileSplitterFetch.bDownOver) HlOAo:8'  
{ =Ov;'MC  
breakWhile = false; o}r!qL0c  
break; l\A}lC0?J  
} ".*a)  
} !DY2{Wb  
if(breakWhile) l"~h1xk~  
break; vJ#rW8y  
!"o1ve`{  
N>F2 c)rm  
//count++; +Zty}fe  
//if(count>4) oJ4mxi@|#  
// siteStop(); ';fU.uy  
} "R\\\I7u  
^Yf)lV&[  
0IT20.~  
System.err.println("文件下载结束!"); fmZzBZ_  
} |2+F I<v4  
catch(Exception e){e.printStackTrace ();} {=pP`HD0  
} {3F}Slb  
Muc*?wB`  
]/<Qn-BbU  
//获得文件长度 y$r?t0  
public long getFileSize() G}9bC r,  
{ a-UD_|!  
int nFileLength = -1; )P(d66yq'u  
try{ 6U,U[MWJ  
URL url = new URL(siteInfoBean.getSSiteURL()); LzEE]i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fO^EMy\  
httpConnection.setRequestProperty("User-Agent","NetFox"); .eDxIWW+ft  
mXN1b!  
6"rFfdns  
int responseCode=httpConnection.getResponseCode(); gl(6m`a>  
if(responseCode>=400) wZ\e3H z  
{ n_!]B_Vd$  
processErrorCode(responseCode); }ii]c Y  
return -2; //-2 represent access is error [w#x5Xsn  
} &s6(3k  
:+Z>nHe  
=Y=^]ayO/  
String sHeader; 46.q a nh  
[<3Q$*Ew  
EiIFVP   
for(int i=1;;i++) [&]YVn>kj  
{ 0F;(_2V-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); t6,M  
//Utility.log(in.readLine()); m?kIa!GM=  
sHeader=httpConnection.getHeaderFieldKey(i); 7Hr4yh[j&  
if(sHeader!=null) J z:W-o  
{ gYH:EuY,  
if(sHeader.equals("Content-Length")) vI:bl~  
{ =-1^K  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5sV/N] !  
break; (>Q9jNW  
} 6Kv}2M')+  
} Q+%m+ /Zq  
else ~1wdAq`'a  
break; GO:1 Z?^  
} J?,!1V=  
} ,[K)E  
catch(IOException e){e.printStackTrace ();} n9-q5X^e>  
catch(Exception e){e.printStackTrace ();} zf!\wY"`  
o"+ &^  
J!^~KN6[  
Utility.log(nFileLength); OD@@O9  
scPq\Qd?O  
% &Q7;?  
return nFileLength; DHujpZXQ  
} E*!zJ,@8  
*IO;`k q,;  
C6=;(=?C  
//保存下载信息(文件指针位置) 'm p{O  
private void write_nPos() XtH_+W+O  
{ +/_B/[e<>  
try{ 8Q)mmkI\=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); da86Jj=k  
output.writeInt(nStartPos.length); K&a]pL6D  
for(int i=0;i<nStartPos.length;i++) {]_{BcK+  
{ *mhw5Z=!  
// output.writeLong(nPos); Uub%s`O  
output.writeLong(fileSplitterFetch.nStartPos); g J[q {b  
output.writeLong(fileSplitterFetch.nEndPos); &fNE9peQFa  
} lt(-,md  
output.close(); p~zTRnm  
} a518N*]j  
catch(IOException e){e.printStackTrace ();} o!_; H}pq  
catch(Exception e){e.printStackTrace ();} Qj~W-^/ -  
} (9[C0eS  
[{!j9E?(  
$E@.G1T [  
//读取保存的下载信息(文件指针位置) u{lDof>  
private void read_nPos() z?) RF[  
{ *$Wx*Jo  
try{ $X\` 7`v  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 63dtO{:4  
int nCount = input.readInt(); #?|1~HC  
nStartPos = new long[nCount]; @aPu}Hi  
nEndPos = new long[nCount]; 2Q_{2(nQb  
for(int i=0;i<nStartPos.length;i++) ws(}K+y_  
{ +nyN+X34B  
nStartPos = input.readLong(); ][K8\  
nEndPos = input.readLong(); &8YI)G%  
} U@t?jTMBkO  
input.close(); VEYKrZA  
} uB&I56  
catch(IOException e){e.printStackTrace ();} SIBIh-L  
catch(Exception e){e.printStackTrace ();} &/#Tk>:  
} i^V4N4ux]  
'*{Rn7B5  
u9~V2>r\  
private void processErrorCode(int nErrorCode) s1b\I6&:J  
{ $8ww]}K  
System.err.println("Error Code : " + nErrorCode); A5H8+gATK  
} k49n9EX  
xA1pDrfC/  
g8qAJ4  
//停止文件下载 &\D<n; 3  
public void siteStop() 1B]wSvP@  
{ DdZ_2B2  
bStop = true; i$<v*$.o  
for(int i=0;i<nStartPos.length;i++) U,3K6AZA 7  
fileSplitterFetch.splitterStop(); nsw8[pk  
~322dG  
i@?<]n  
} ( =/L#Yg_  
} ScmzbDu  
//负责部分文件的抓取 yW,#&>]# |  
**FileSplitterFetch.java gl{P LLe[}  
*/ +q?0A^C>  
package NetFox; Nm :lC%>X  
2o3k=hKS  
GQAg ex)D  
import java.io.*; ^|12~d_.T  
import java.net.*; M]zNW{Xt  
0+`*8G)  
zgOwSg8  
public class FileSplitterFetch extends Thread { b0CaoSWo  
u^.k"46hn  
<T~fh>a  
String sURL; //File URL RpXGgw  
long nStartPos; //File Snippet Start Position &XTd[_VW!  
long nEndPos; //File Snippet End Position EC\:uK  
int nThreadID; //Thread's ID gK_[3FiKt  
boolean bDownOver = false; //Downing is over (dnc7KrM  
boolean bStop = false; //Stop identical K]Cs2IpI  
FileAccessI fileAccessI = null; //File Access interface ;xC~{O  
HQj4h]O#  
JWjp<{Q; 1  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :v ~q  
{ ~l(tl[  
this.sURL = sURL; }(I DPaJ  
this.nStartPos = nStart; BJ2W }R  
this.nEndPos = nEnd; &IY_z0=  
nThreadID = id; ' "p*FN  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 exU=!3Ji  
} otVdx&%]  
8pt<)Rs}  
Y-k~ 7{7  
public void run() MM$" 6Jor  
{ 0s[3:bZ\Ia  
while(nStartPos < nEndPos && !bStop) Mp}NUQHE  
{ d(tf: @  
PS;*N 8  
dV*rnpN  
try{ $ aBSr1  
URL url = new URL(sURL); m8A1^ R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A{T@O5ucj  
httpConnection.setRequestProperty("User-Agent","NetFox"); m|gd9m $,?  
String sProperty = "bytes="+nStartPos+"-"; D??/=`|8  
httpConnection.setRequestProperty("RANGE",sProperty); dp W%LXM_  
Utility.log(sProperty); ;XuE Mq,Di  
n,LKkOG  
AdW7 vn  
InputStream input = httpConnection.getInputStream(); X.5LB!I)  
//logResponseHead(httpConnection); |W];v@b\y  
eV}Tx;1|}  
LMj'?SuH  
byte[] b = new byte[1024]; nECf2>Yp v  
int nRead; ;P#*R3   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) t O;W?g  
{ 8uW:_t]q  
nStartPos += fileAccessI.write(b,0,nRead); PX/0  jv  
//if(nThreadID == 1) ?2>v5p  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5!p'n#_  
} _ 9]3S>Rn  
I"?&X4%e  
e!'u{>u  
Utility.log("Thread " + nThreadID + " is over!"); (19<8a9G  
bDownOver = true; u6d~d\  
//nPos = fileAccessI.write (b,0,nRead); }f*S 9V  
} XmR5dLc8  
catch(Exception e){e.printStackTrace ();} <Wq{ V;$  
} /hR]aw  
} Mc^7FWkw  
ixpG[8s  
mSeN M  
//打印回应的头信息 '~a$f;: Dv  
public void logResponseHead(HttpURLConnection con) fbkjK`_q  
{ "b7C0NE  
for(int i=1;;i++) IV*$U7~  
{ >:|q J$J.  
String header=con.getHeaderFieldKey(i); nP5fh_/  
if(header!=null) 1OS3Gv8jc~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); zjE4v-H:l  
Utility.log(header+" : "+con.getHeaderField(header)); cNv c pv  
else ( "z;Q?(  
break; 3&:fS|L~c  
} 3f8Z ?[Bb@  
} - mXr6R?  
FQl|<l6  
11+_OC2-   
public void splitterStop() [)u{-  
{ :E*U*#h/  
bStop = true; NWj@iyi<  
} C =U4|h~W  
KHiJOeLc  
CgE5;O  
} zf u78  
(DAJ(r~  
5)6%D  
/* +06j+I  
**FileAccess.java n3,wwymQ  
*//文件访问(定位,写) gu&oCT  
package NetFox; ij5YV3  
import java.io.*; KR0 x[#.*  
T667&@  
(0f^Hh wF  
public class FileAccessI implements Serializable{ LcF3P 4  
:LG%8Z{R  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 A4h/oMis  
RandomAccessFile oSavedFile; h65j,v6B  
long nPos; rg.if"o  
H)tDfk sq\  
F{tSfKy2  
public FileAccessI() throws IOException ~G:7*:[b  
{ cw{[B%vw  
this("",0); Y?cw9uYB  
} v^'~-^s  
iSHl_/I<  
nrBitu,  
public FileAccessI(String sName,long nPos) throws IOException <X*8Xzmv  
{ -}o;Y)  
oSavedFile = new RandomAccessFile(sName,"rw"); _#B/# ^a  
this.nPos = nPos; 5;Xrf=  
oSavedFile.seek(nPos); ;"z>p25=T  
} 9v0|lS!-  
Nig-D>OS  
F eLP!oS>  
public synchronized int write(byte[] b,int nStart,int nLen) V ;jz0B  
{ /G;yxdb  
int n = -1; Y2EN!{YU  
try{ !)34tu2  
oSavedFile.write(b,nStart,nLen); ZbUf|#GTB  
n = nLen; p6'8l~W+  
} b??1Up  
catch(IOException e) (P-<9y@  
{ K2 2Xo<3  
e.printStackTrace (); g_U69 z  
} X Rn=;gK%J  
+&@0;zSga  
UEUTu}4y  
return n; eHR<(8c'f  
} pJ[Q.QxU  
iXFaQ  
9K!='u`  
} .2xkf@OP  
2X_ef  
ZI7<E  
/* )RFeF!("  
**SiteInfoBean.java Sqs`E[G*  
*/ _rd{cvdR  
package NetFox; -}@9lhS,  
xTT>3Fj  
xFZq6si?  
public class SiteInfoBean { s?Kn,6Y  
}T,uw8?f!  
>YLm]7v}  
private String sSiteURL; //Site's URL v &n &i?  
private String sFilePath; //Saved File's Path oWmla*nCKL  
private String sFileName; //Saved File's Name WmA578|l!  
private int nSplitter; //Count of Splited Downloading File {Y Ymt!Ic  
8*wI^*Q  
e+wd>iiB  
public SiteInfoBean() zu#o<6E{  
{//nSplitter的缺省值为5 D 3PF(Wx  
//default value of nSplitter is 5 0N.*c  
this("","","",5); jTnu! H2o  
} /7^~*  
'#PT C,0UJ  
PW}.`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Cp%|Q.?  
{ Ee O{G*pq  
sSiteURL= sURL; c'b,=SM  
sFilePath = sPath; FWg7 e3  
sFileName = sName; cu-WY8n  
this.nSplitter = nSpiltter; ]G:xTv8  
m| Z)h{&  
[C$ 0HW  
} #_d%hr~d  
}1V&(#H2  
|($pXVLH`  
public String getSSiteURL() XebCl{HHp  
{ uT1x\Rt|e  
return sSiteURL; _D~a4tgS  
} k{~5pxd-t  
Y*Pr  
D)5wGp  
public void setSSiteURL(String value) VI?[8@*Z  
{ "q$M\jK#V  
sSiteURL = value;  X_lNnk  
} nB.p}k  
$IHa]9 {  
b|NEU-oy  
public String getSFilePath() ^N]*Zf~N?  
{ oW6.c]Vo  
return sFilePath; WCH>9Z>cj  
} $Ix^Rm9c  
}^H_|;e1p  
*b&|  
public void setSFilePath(String value) 7% h Mf$KQ  
{ sdb#K?l  
sFilePath = value; 7$'ja  
} 9;PtY dJ8  
x RfX:3  
PF.HYtZqK  
public String getSFileName() "ggq7cJ}_  
{ V|7 c dX#H  
return sFileName; 8L:0Wp  
} (f)QEho7  
FEkx&9]  
s[hD9$VB>  
public void setSFileName(String value) S7bSR?~L[  
{ 8:f( PN  
sFileName = value; v[m>;Ubg&  
} 4h|vd.t  
[Y[|:_+5  
fA8 ,wy|>  
public int getNSplitter() ?g 3sv5\u  
{ COap*  
return nSplitter; 'G&w[8mqY  
} d$!ibL#o  
y=t -/*K  
8W{R&Z7aL  
public void setNSplitter(int nCount) &:rf80`z.  
{ EB \\ F  
nSplitter = nCount; F J)la9  
} J&Ah52  
} n}"MF>zDK  
+p2)uXqW  
hQ9VcS6=gD  
/* j:0z/gHp$  
**Utility.java ` sSI;+  
*/ k]Yd4CC2  
package NetFox; E11"uWk`  
*p"%cas  
% 74}H8q_z  
public class Utility { k3&Wv  
;aSEv"iWX  
K#>B'>A\  
public Utility() gD-<^Q-  
{ xu3qX"  
>6c{CYuT  
#<{sP 0v*  
} =7a9~&|  
sPut@4[S  
//线程睡眠 Lx.X#n.]T  
public static void sleep(int nSecond) ~MOIrF  
{ 0L'h5i>H)  
try{ [l0>pHl@  
Thread.sleep(nSecond); )gZ yW  
} zFlW\wc  
catch(Exception e) |1#*`2j\=9  
{ s q_ f[!  
e.printStackTrace (); OF}vY0oiw?  
} z Mtx>VI  
} LKhUqW  
y:mXv<g  
//日志 V V<Zl  
public static void log(String sMsg) Z\n nVM=  
{ Gx!Y 4Q}-  
System.err.println(sMsg); o<Q~pd#Ip,  
} Wh,p$|vL  
`rvS(p[s  
KrB"2e+J  
public static void log(int sMsg) uZCPxog  
{ L+&$/1h]  
System.err.println(sMsg); zpJQ7hym  
} F&^u1RYz  
} vLq_l4l  
(<|,LagTuc  
3:s!0ty"  
/* G22u+ua  
**TestMethod.java O.i.<VD7  
*/ C1hp2CW$5/  
package NetFox; n}EH{k9#  
A\LMmg  
!IcP O  
public class TestMethod { af)L+%Q%R  
.^eajb`:  
EW]rD  
public TestMethod() #V@[<S2  
{ ///xx/weblogic60b2_win.exe xtyOG  
try{ ^tI ,eZ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `Ps&N^[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?|kwYA$4o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); C h>r.OfP  
fileFetch.start(); )m|)cLT&  
} f]Xh7m(Gh  
catch(Exception e){e.printStackTrace ();} UZz/v#y~  
1 Qln|b8<  
zt6GJ z1q  
} Kqm2TMO]>V  
y2KR^/LN|Y  
7*.nd  
public static void main(String[] args) :>f}rq  
{ /@ m]@  
new TestMethod(); -V7dSi  
} /V0[Urc@  
} Fsz;T;  
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