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http断点续传简单实现(java)

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/* !9e=_mY  
**SiteFileFetch.java J*A,o~U|  
*/ | YWD8 +  
package NetFox; adcE'fA<_  
import java.io.*; [|$h*YK  
import java.net.*; {S)6;|ua'  
O=t_yy  
Ll't>)  
public class SiteFileFetch extends Thread { YkSl^j[DHs  
+Kc  
&r /Mi%  
SiteInfoBean siteInfoBean = null; //文件信息Bean $%d*@ 'c  
long[] nStartPos; //开始位置 V f&zL Sgr  
long[] nEndPos; //结束位置 BDDlQci38  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 O0v}43J [  
long nFileLength; //文件长度 F/{!tx  
boolean bFirst = true; //是否第一次取文件 T'9'G M  
boolean bStop = false; //停止标志 Sz`,X0a  
File tmpFile; //文件下载的临时信息 t3_O H^  
DataOutputStream output; //输出到文件的输出流 0#hlsfc]\  
1CZgb   
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `U_)98  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6d}lw6L  
{ 8TKnL\aar  
siteInfoBean = bean;  V}CG:9;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); cuI TY^6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _TZRVa_  
if(tmpFile.exists ()) h438`  
{ (?c"$|^J  
bFirst = false; FVKTbvYn  
read_nPos(); UI0VtR]   
} 2%m BK  
else 2/^3WY1U  
{ </z Eg3F\  
nStartPos = new long[bean.getNSplitter()]; C,r;VyW6BI  
nEndPos = new long[bean.getNSplitter()]; <%eG:n,#  
} U8?mc  
(L&d!$,Dv  
[z{1*Xc  
{!L~@r  
} 9Y9GwL]T  
Lqa4Vi  
%tGO?JMkd  
public void run() ^yp{32  
{ \R_C&=  
//获得文件长度 Ti5-6%~&  
//分割文件 _G@GpkSe>  
//实例FileSplitterFetch ZY+qA  
//启动FileSplitterFetch线程 ;A*]l' [-  
//等待子线程返回 ?:q*(EC<  
try{ XRi8Gpg  
if(bFirst) m:2^= l4  
{ 73;GW4,  
nFileLength = getFileSize(); CD~.z7,LC  
if(nFileLength == -1) 7?_CcRe  
{ L="}E rmK  
System.err.println("File Length is not known!"); $U~]=.n  
} m-, x<bM?  
else if(nFileLength == -2) PJH&  
{ rV#ch(  
System.err.println("File is not access!"); /U9"wvg  
} :$c |  
else F]&*o w  
{ +mn[5Y}:  
for(int i=0;i<nStartPos.length;i++) q/,O\,  
{ X \/#@T  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NBGH_6DROw  
} e\L8oOk#r  
for(int i=0;i<nEndPos.length-1;i++) z Iu'[U  
{ )SGq[B6@I  
nEndPos = nStartPos[i+1]; }|=|s f  
} rx|pOz,:  
nEndPos[nEndPos.length-1] = nFileLength; 4V`G,W4^J  
} G"t5nHY\.  
} a:w#s}bL  
&^jXEz;  
%.|@]!C  
//启动子线程 Km$\:Xo  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _t^&Ah*  
for(int i=0;i<nStartPos.length;i++) Dlvz )  
{ NzvXN1_%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |+9&rAg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), dy[X3jQB  
nStartPos,nEndPos,i); YT,{E,U;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d2$IH#~9B  
fileSplitterFetch.start(); OneY_<*a<  
} Q=$2c[Uk  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J|73.&B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vFmZ<C' )  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3bI9Zt#J%&  
nEndPos = " + nFileLength); es7=%!0  
// fileSplitterFetch[nPos.length-1].start(); &oMh]Z*:  
"w<#^d_6  
kAUymds;O  
//等待子线程结束 ZN0P:==  
//int count = 0; ~P-mC@C  
//是否结束while循环 |FRg\#kf%  
boolean breakWhile = false; [nq@mc~<  
v]UwJz3<  
(T oUgVW1N  
while(!bStop) xAm6BB c  
{ Ny/MJ#Lq  
write_nPos(); $F.a><1rY  
Utility.sleep(500); )^hbsMhO  
breakWhile = true; #RLt^$!H  
J{G?-+`  
C0Z=~Q%  
for(int i=0;i<nStartPos.length;i++) >vsqG=x  
{ _+MJ%'>S  
if(!fileSplitterFetch.bDownOver) GM<9p_ B  
{ I> $&-i  
breakWhile = false; OY({.uVdX  
break; hDGF7  
} E]r?{t`]  
} owv[M6lbD  
if(breakWhile) |R:'\+E  
break; wMN]~|z>  
|_U= z;Y  
rytyw77t(  
//count++; !;'=iNOYR  
//if(count>4) d0> zS  
// siteStop(); klhtKp_p  
} F:DrX_O%  
_)-o1`*-  
FpU>^'2]  
System.err.println("文件下载结束!"); d#wVLmKZ  
} q@2siI~W  
catch(Exception e){e.printStackTrace ();} f*8DCh!r"  
} /Z4et'Lo  
?aMOZn?  
69.NPy@  
//获得文件长度 TD_Oo-+\  
public long getFileSize() <#HYqR',  
{ hE-M$LmN@  
int nFileLength = -1; /qw.p#  
try{ bg0Wnl  
URL url = new URL(siteInfoBean.getSSiteURL()); m#p'iU*va,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  9gZ$   
httpConnection.setRequestProperty("User-Agent","NetFox"); P!k{u^$L  
|ENh)M8}r  
kG*~ |ma  
int responseCode=httpConnection.getResponseCode(); NGWxN8P6  
if(responseCode>=400) |wj?ed$ f  
{ /Ci<xmP  
processErrorCode(responseCode); bZV/l4TU  
return -2; //-2 represent access is error #.[k=dj   
} 3;Fhg!Z O  
vvOV2n .WD  
9nbLg5P  
String sHeader; zx7{U8*`<  
u#SWj,X  
3+bt~J0  
for(int i=1;;i++) D1;QC  
{ <9 ;!3xG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {l >hMxij  
//Utility.log(in.readLine()); +nGAz{&@r%  
sHeader=httpConnection.getHeaderFieldKey(i); Y6d@h? ht  
if(sHeader!=null) vr^qWn  
{ 0ZO2#>gh$  
if(sHeader.equals("Content-Length")) @=kSo -SX  
{ sx<%2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %~S&AE-  
break; DlNX 3  
} igAtRX%Qx  
} _J[P[(ab  
else ;A!BVq  
break; 7x a>  
} Q NVa?'0"Y  
} F4{IEZ  
catch(IOException e){e.printStackTrace ();} >&k-'`Nw  
catch(Exception e){e.printStackTrace ();} S21,VpW\  
^Zp>G{QL{  
POR\e|hRT]  
Utility.log(nFileLength); L j$;:/G  
!{41!O,K#  
G*v,GR  
return nFileLength; >lM l  
} &jr3B;g!C  
& ZB  
E1f\%!2l  
//保存下载信息(文件指针位置) 2GStN74Xr  
private void write_nPos() ~y[7K{{ ;T  
{ Mb7I[5v  
try{ >-{Hyx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !0E&@X:-  
output.writeInt(nStartPos.length); ws^ np  
for(int i=0;i<nStartPos.length;i++) 7J&4akT{9  
{ SK.: Q5:  
// output.writeLong(nPos); pY$Q  
output.writeLong(fileSplitterFetch.nStartPos); <b<j=_3  
output.writeLong(fileSplitterFetch.nEndPos); GowH]MO  
} jlg(drTo  
output.close(); >&#)Tqt!?  
} 5rUdv}.  
catch(IOException e){e.printStackTrace ();} @ur+;IK$  
catch(Exception e){e.printStackTrace ();} T9q-,w/j;  
} aFIw=c(nP  
W`*r>`krVJ  
/5AJ.r  
//读取保存的下载信息(文件指针位置) FU<Jp3<%  
private void read_nPos() XBw)H  
{ S#[j )U-  
try{ :P=(k2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Oz#{S:24M+  
int nCount = input.readInt(); w)jISu;RG  
nStartPos = new long[nCount]; G<;*SYAb  
nEndPos = new long[nCount]; S>; 5[l 4  
for(int i=0;i<nStartPos.length;i++) 9 JK Ew  
{ HLHz2-lI  
nStartPos = input.readLong(); 7})[lL`\s  
nEndPos = input.readLong(); cPc</[x[W  
} ]]j;/TiG  
input.close(); {2 "zVt#h  
} ~.lPEA %%  
catch(IOException e){e.printStackTrace ();} xA[mm  
catch(Exception e){e.printStackTrace ();} Q.c\/&  
} ROZF)|l  
w.-!UD9/.x  
*G 9V'9  
private void processErrorCode(int nErrorCode) k+l b@!  
{ 9k[9P;"F:  
System.err.println("Error Code : " + nErrorCode); 8qu6.  
} n@[O|?S  
-;k+GrLr^  
"Os_vlapHo  
//停止文件下载 xFg>SJ7]  
public void siteStop() wo 5   
{ SOvF[,+  
bStop = true; `n?DU;,  
for(int i=0;i<nStartPos.length;i++) c-FcEW  
fileSplitterFetch.splitterStop(); t.\dpBq  
i<g-+Qs  
%BB%pC  
} ^D-/`d  
} w917N 4$  
//负责部分文件的抓取 j^2j& Ta  
**FileSplitterFetch.java {+Cy U!O  
*/ QoH6  
package NetFox; @49S`  
0Pi:N{x8  
&~U ]~;@  
import java.io.*; B@ KQ]4-  
import java.net.*; ('p5:d  
Tc3yS(aq  
^\,E&=/}M  
public class FileSplitterFetch extends Thread { WvZ8/T'x  
0NX,QD  
c_!cv":s  
String sURL; //File URL l0i^uMS  
long nStartPos; //File Snippet Start Position "i W"NFO  
long nEndPos; //File Snippet End Position )B8$<sv  
int nThreadID; //Thread's ID r^ ZEImjc  
boolean bDownOver = false; //Downing is over D=&Me=$  
boolean bStop = false; //Stop identical K8Y=S12Ti  
FileAccessI fileAccessI = null; //File Access interface 4)o  
$\y'I Q%  
gjzuG< 7m  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i,9)\1R  
{ 7EO_5/cY  
this.sURL = sURL; PXNh&N  
this.nStartPos = nStart; WVvvI9  
this.nEndPos = nEnd; 6<(.4a?  
nThreadID = id; fXQNHZ|4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 i&GH/y  
} Xh;#  
zjoq6  
gEE\y{y  
public void run() Qv/=&_6  
{ Hc(OI|z~  
while(nStartPos < nEndPos && !bStop) kt$jm)UI~l  
{ ZbAcO/  
[Hh9a;.*}h  
y9}>:pj4  
try{ $l&(%\pp  
URL url = new URL(sURL); a-L;*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *,WU?tl&  
httpConnection.setRequestProperty("User-Agent","NetFox"); UFb )AnK  
String sProperty = "bytes="+nStartPos+"-"; / FEVmH?  
httpConnection.setRequestProperty("RANGE",sProperty); L8#5*8W6  
Utility.log(sProperty); OX\F~+  
O/(xj2~$ J  
vTw>JNVI  
InputStream input = httpConnection.getInputStream(); GYUn6P  
//logResponseHead(httpConnection); p,i[W.dy.'  
'u<juFr  
(;^syJrh  
byte[] b = new byte[1024]; J!U}iD@occ  
int nRead; Pw!MS5=r  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ChXq4]  
{ -Wi` G  
nStartPos += fileAccessI.write(b,0,nRead);  p|D/;Mk  
//if(nThreadID == 1) scLll,~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BbS4m  
} c.F6~IHu7  
) M BQuiL  
qR+!l(  
Utility.log("Thread " + nThreadID + " is over!"); 54li^   
bDownOver = true; Dy8r 9  
//nPos = fileAccessI.write (b,0,nRead); cY.bO/&l  
} agW@ {c  
catch(Exception e){e.printStackTrace ();} ysf~|r4s  
} W'+:'_{j:  
} 2Dj%,gaR  
:@A9](gI  
_8UDT^?8,  
//打印回应的头信息 M%;hB*9  
public void logResponseHead(HttpURLConnection con) L.0mk_&  
{ ]G< Vg5  
for(int i=1;;i++) a]tVd#  
{ Px`!A EFd[  
String header=con.getHeaderFieldKey(i); ':m,)G5&  
if(header!=null) ly3\e_z:G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); HcSXsF  
Utility.log(header+" : "+con.getHeaderField(header)); Y,t={HiclX  
else ,0HRAmG  
break; F,)%?<!I  
} nq8C'Fo!6T  
} 2Gaa(rJ5o  
6]%sFy2  
* U=s\  
public void splitterStop() ;&-k#PE]/H  
{ ; _1 at  
bStop = true; rK]Cr9WM  
} =CVBBuVy  
}"!I[Ek> y  
:I^;jdL  
} x-.?HS[  
t$#jL5  
vJOw]cwq  
/* XtSkh] #z!  
**FileAccess.java uurh??R  
*//文件访问(定位,写)  dZ0vA\z|  
package NetFox; s 3f-7f<  
import java.io.*; o;<Xo&  
(tw)nF  
@8rx`9  
public class FileAccessI implements Serializable{ 0-yp,G  
H{?vbqQ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 "v({ ,  
RandomAccessFile oSavedFile;  e5*hE  
long nPos; [o+q>|q  
T\j{Bi5 \J  
8jo p_PG'  
public FileAccessI() throws IOException 90*5 5\>{  
{ `gf0l /d  
this("",0); D}8[bWF  
} 8MzVOF{"  
)@Yf]qx+Y<  
mtmjZP(w   
public FileAccessI(String sName,long nPos) throws IOException Y^}Z>  
{ x&Kh>PVh\  
oSavedFile = new RandomAccessFile(sName,"rw"); p &"`RS #Z  
this.nPos = nPos; W~9tKT4  
oSavedFile.seek(nPos); qjdMqoOCjl  
} (VEpVn3{  
e MY<uqdw  
ah0`KxO]  
public synchronized int write(byte[] b,int nStart,int nLen) # ,_u_'C*!  
{ ,-d 0b0  
int n = -1; *ipFwQ  
try{ MUREiL9L|  
oSavedFile.write(b,nStart,nLen); 4UvZ)^r  
n = nLen; MWpQ^dL_  
} 4DOH`6#an  
catch(IOException e) pRIhFf  
{ p=GBUII #  
e.printStackTrace (); g<f <Ip=  
} N&g3t%F  
b Y\K  
5l2 ?  
return n; IIF] /Ek]  
} se>8Z4  
hYNY"VB  
k_5L4c:"  
} q?DTMKx  
vZ&T}H~8  
iwp{%FF  
/* CpeU5 o@  
**SiteInfoBean.java 4N zwE(  
*/ _Wp{ [TH  
package NetFox; %GA"GYL9'  
Xr$J9*Jk-  
BJsz2t :0  
public class SiteInfoBean { W;L7SF g)  
C|). ;V&  
wq(7|!Eix  
private String sSiteURL; //Site's URL (@<c6WS  
private String sFilePath; //Saved File's Path ],FMwCI  
private String sFileName; //Saved File's Name 9~mh@Kgv  
private int nSplitter; //Count of Splited Downloading File JedmaY06=  
L> 9V&\  
8WbgSY`  
public SiteInfoBean() f'-i o<.  
{//nSplitter的缺省值为5 aM2l2  
//default value of nSplitter is 5 )Sg~[WxDv  
this("","","",5); hj B@o#S  
} dWUm\t'#  
"UGY2skf;  
_w/EP  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4UlyxA~   
{ w' OXlR  
sSiteURL= sURL; I^UC&5dC  
sFilePath = sPath; (-xS?8x$  
sFileName = sName; NI#:|}CYS  
this.nSplitter = nSpiltter; ,5kKimTt  
7;sj%U^'l  
bRJMYs  
} 5eoska#y   
/ !Wu D\B  
}Q?c"H!/  
public String getSSiteURL() Hh-+/sO~"  
{ %?uc><&?e  
return sSiteURL; ;WM"cJo9  
} $Ifmc`r1  
cU@SIJ)  
[}/LD3  
public void setSSiteURL(String value) u7\J\r4,+  
{ /#-C4"|  
sSiteURL = value; R)z4n  
} {QZUDPPR  
*4xat:@{{  
SHbtWq}T  
public String getSFilePath() ~\.w^*$#Y  
{ ^3{TZ=_;|  
return sFilePath; OK6] e3UO  
} ;04Ldb1{|3  
L ugn 3+  
Rhz_t@e  
public void setSFilePath(String value) W?aI|U1  
{ RGg(%.  
sFilePath = value; S\5bmvqP"  
} B}?5]N==]  
C>$E%=h+_  
2H6,'JK@F  
public String getSFileName() j =WST  
{ qg!|l7e  
return sFileName; ~j5x+yC  
} #iWSDy  
}L3oR  
]Nl=wZ#`  
public void setSFileName(String value) 2viM)+  
{ mc_ch$r!  
sFileName = value; 9@52Fg ;mj  
} *R3f{/DK  
PBxCx3a{  
X4t s)>"d  
public int getNSplitter() .k9{Yv0  
{ 7J|VD#DE$Y  
return nSplitter; 0-|byAh  
} \B 0ywN?  
2Sp=rI  
pN9A{v(  
public void setNSplitter(int nCount) %8Dz o  
{ a{J,~2>  
nSplitter = nCount; Eam  
} dBe`p5Z  
} oiyzHx  
Tp?y8r  
s]mY*@a%  
/* dd%h67J2<  
**Utility.java : G`hm{  
*/ DrBUe'RH:M  
package NetFox; _ozg_E  
~r$jza~o(  
,0~9dS   
public class Utility { :l&V]}:7*  
^#1.l=s  
?(m jx  
public Utility() tBT<EV{ G  
{ AfP 'EP0m  
MpqZH{:?G  
B`o]*"xkB  
} 0i|oYaC  
rBTeb0i?  
//线程睡眠 C2xL1`  
public static void sleep(int nSecond) 4jBC9b}O  
{ <~!Hx+j   
try{ eKz?"g/j  
Thread.sleep(nSecond); iNWo"=J  
} HJ[/|NZU$  
catch(Exception e) ~7t$MF.  
{ ,4,V4 N  
e.printStackTrace (); 0}FOV`n  
} ""h)LUrl  
} )a3J9a;ZS0  
,H2D  
//日志 f{i8w!O"~  
public static void log(String sMsg) N, *m ,  
{ D?,#aB"  
System.err.println(sMsg); M$d%p6Cv  
} G4;3cT3'  
aKlUX  
Cb@3M"1:  
public static void log(int sMsg) 1q3( @D5~+  
{ R:AA,^Z  
System.err.println(sMsg); 1>Dl\czn  
} 5"]~oPK  
} =rQP[ICs!  
-}4NT{E  
pge++Di  
/* { "xln/  
**TestMethod.java :nS;W  
*/ G,<T/f .{$  
package NetFox; A'K%WW*'U  
#nO|A\N  
d90Z,nex  
public class TestMethod { 7GS V  
G #T<`>T  
B_l{<  
public TestMethod() m6yIR6H  
{ ///xx/weblogic60b2_win.exe t"lyvI[  
try{ p,<&zHb>K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `)h6j)xiQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jWO/ xX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); GK}'R=   
fileFetch.start(); M9f?q.Bv  
} !k(_PM  
catch(Exception e){e.printStackTrace ();} {(#%N5%  
Hb(B?!M)  
^*= 85iyo  
} N+)?$[  
0hn-FH-XE  
Q2];RS3.  
public static void main(String[] args) ?Xo*1Z =  
{ 70Yjv 1i  
new TestMethod(); bo=ZM9  
} %tt%`0  
} A[dvEb;r  
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