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http断点续传简单实现(java)

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/* =W+ h.?  
**SiteFileFetch.java DH7B4P  
*/ ""AP-7  
package NetFox; e,j2#wjor  
import java.io.*; ,'=Tf=wq  
import java.net.*; }M3f ?Jv  
LjZvWts?  
h7],/? s  
public class SiteFileFetch extends Thread { kR+xInDM*  
w8MQA!=l  
:X1~  
SiteInfoBean siteInfoBean = null; //文件信息Bean &x~&]  
long[] nStartPos; //开始位置 ;Y/{q B!  
long[] nEndPos; //结束位置 l,z# : k  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 BGk>:Z`  
long nFileLength; //文件长度 IZr~h9  
boolean bFirst = true; //是否第一次取文件 =+I~K'2  
boolean bStop = false; //停止标志 >F@qFP N]  
File tmpFile; //文件下载的临时信息 N0Y$QWr_$  
DataOutputStream output; //输出到文件的输出流 R^_7B(  
G)p pkH`qj  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) }b$?t7Q)  
public SiteFileFetch(SiteInfoBean bean) throws IOException q?R)9E$h  
{ #Az#dt]H  
siteInfoBean = bean; JCL+uEX4S  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); YIP /N  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <Mdyz!  
if(tmpFile.exists ()) jO` b&]0  
{ 5AX AIPn)  
bFirst = false; N^G $:GC  
read_nPos(); G~$.Af!9W  
} H C %tJ:G  
else D'{NEk@  
{ J[Ck z]  
nStartPos = new long[bean.getNSplitter()]; B =EI&+F+  
nEndPos = new long[bean.getNSplitter()]; <F>^ffwGH-  
} H2f!c{t$p  
ySfot`LQ  
[C8lMEV~  
NNKI+!vg  
} hxCSE$f4  
h8nJt>h  
dC&OjBQ  
public void run() ]lT8Z-h@  
{ {}sF ?wZf  
//获得文件长度 kIC $ai6.  
//分割文件 cst}/8e  
//实例FileSplitterFetch h/)kd3$*'  
//启动FileSplitterFetch线程 y4@zi"G  
//等待子线程返回 Q9i&]V[`  
try{ n! Dr:$  
if(bFirst) L|?$F*bs  
{ "aU) [  
nFileLength = getFileSize(); e;|:W A  
if(nFileLength == -1) QR ?JN\%?  
{ mJ_ 5Vt=  
System.err.println("File Length is not known!"); \?$`dA[  
} 1g{-DIOmn  
else if(nFileLength == -2) :V9%R~h/  
{ r<%ua6@  
System.err.println("File is not access!"); _/S qw  
} |41NRGgY  
else #Nv^F  
{ m{ wk0  
for(int i=0;i<nStartPos.length;i++) s6DmZ^Y%  
{ 3j I rB%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NsPAWI|4  
} f:\)oIW9Kk  
for(int i=0;i<nEndPos.length-1;i++) <:n !qQS6  
{ azs lNL  
nEndPos = nStartPos[i+1]; ?Z0NHy;5  
} rN3qTp  
nEndPos[nEndPos.length-1] = nFileLength; ~E8L,h~  
} [$Dzf<0  
} 8 t)?$j$  
F3?PlH:Y  
Q)IL]S  
//启动子线程 nxjP4d>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; X([8TR  
for(int i=0;i<nStartPos.length;i++) /<R[X>]<F  
{ @W1F4HYds  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +W%3VV$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), > u!# 4  
nStartPos,nEndPos,i); vG{lxPIj  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nOCCOTf  
fileSplitterFetch.start(); .eHOG]H  
} ]aMeMhe-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W>o>Y$H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;:]#Isq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", jU9\BYUg  
nEndPos = " + nFileLength); u)4eu,MBT  
// fileSplitterFetch[nPos.length-1].start(); S8dX8,qg  
W^k|*Y|  
c+:XaDS-  
//等待子线程结束 T&q0TBT  
//int count = 0; '@{Mq%`  
//是否结束while循环 V{{Xz:   
boolean breakWhile = false; YAsE,M+  
$`&zIz  
?/1Eu47  
while(!bStop) $X_A 74 (  
{ 8W2oGL6  
write_nPos(); =L]GQ=d  
Utility.sleep(500); BW x=Q  
breakWhile = true; [e`e bn[C  
:V!F~  
M-V{(  
for(int i=0;i<nStartPos.length;i++) (Zoopkxw  
{ I/hq8v~S  
if(!fileSplitterFetch.bDownOver) I /z`)  
{ l 2ARM3"  
breakWhile = false; v+vM:At4  
break; AF\gB2^  
}  va [r~  
} ZZ324UuATX  
if(breakWhile) EdTR]}8  
break;  ae>B0#=  
T9\G,;VQ7/  
e|d~&Bk0  
//count++; =$-+~  
//if(count>4) JFu9_=%+  
// siteStop(); 8P* d  
} 1d 1 ~`B  
se@ ?:n1)  
w2) @o >w  
System.err.println("文件下载结束!"); d T7!+)s5-  
} >zo_}A!  
catch(Exception e){e.printStackTrace ();} /liZ|K3A  
} g `(3r  
)?{jD  
a];1)zVA6  
//获得文件长度 2&zklXuo:  
public long getFileSize() )l H`a  
{ ?UV|m  
int nFileLength = -1; JqV}>"WMV  
try{ dK41NLGQ  
URL url = new URL(siteInfoBean.getSSiteURL()); 7hhv/9L1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z#B(1uI  
httpConnection.setRequestProperty("User-Agent","NetFox"); )I"I[jDw  
:n,x?bM  
M.67[Qj~"u  
int responseCode=httpConnection.getResponseCode(); [nf 5<  
if(responseCode>=400) @~bP|a  
{ g&rz*)|/  
processErrorCode(responseCode); gu "@*,hL  
return -2; //-2 represent access is error eig{~3  
} U%n>(!d  
e F)my  
9t!Agxm  
String sHeader; V8rS~'{\  
LKBh{X0%(  
tYp 185  
for(int i=1;;i++) biPj(Dd  
{ *).!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7c!#e=W@B  
//Utility.log(in.readLine()); S 3s6  
sHeader=httpConnection.getHeaderFieldKey(i); tL M@o|:  
if(sHeader!=null) $Lz!04  
{ 2U3e!V  
if(sHeader.equals("Content-Length")) LIll@2[  
{ HWFL u  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &crR nv ?  
break; n~ZZX={a  
} (Q=:ln;kM  
} 1DlXsup&?#  
else &3Lhb}m  
break; zt!7aVm n  
} \Vpv78QF;  
} ^kke  
catch(IOException e){e.printStackTrace ();} PZVH=dagq  
catch(Exception e){e.printStackTrace ();} BIEq(/-  
_WZ{i,  
tRo` @eEX  
Utility.log(nFileLength); ] Upr<!  
)q`.tsR>  
51-'*Y  
return nFileLength; ~14|y|\/  
} xd\ml 37~  
2f1Q&S  
+BDW1%  
//保存下载信息(文件指针位置) ;ik,6_/Y  
private void write_nPos() WcY$=\7  
{ z4(`>z2a  
try{ S$gLL kD1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); luW"|  
output.writeInt(nStartPos.length); I>q!co9n  
for(int i=0;i<nStartPos.length;i++) .<Ays?  
{ m6'9Id-:L  
// output.writeLong(nPos); x.$cP  
output.writeLong(fileSplitterFetch.nStartPos); hhz#I A6,  
output.writeLong(fileSplitterFetch.nEndPos); uzT+,  
} o_BRsJy  
output.close(); ;GKL[ tI"  
} my/KsB  
catch(IOException e){e.printStackTrace ();} abv*X 1  
catch(Exception e){e.printStackTrace ();} 9m)gp19YA  
} *U}-Y*  
e.^?hwl  
)!U@:x\K  
//读取保存的下载信息(文件指针位置) fg lN_  
private void read_nPos() DWEDL[{  
{ |UB)q5I  
try{ p+5J  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T]/5aA4  
int nCount = input.readInt(); fP6\Ur  
nStartPos = new long[nCount]; YWJ$Pp  
nEndPos = new long[nCount]; _s<s14+od  
for(int i=0;i<nStartPos.length;i++) ^I yYck'y+  
{ y^[t3XA6Q  
nStartPos = input.readLong(); A@Lr(L  
nEndPos = input.readLong(); uF1&m5^W  
} sSc~q+xz  
input.close(); P#Whh  
} T 1R~^x1  
catch(IOException e){e.printStackTrace ();} j9yOkaVEg  
catch(Exception e){e.printStackTrace ();} ng~LCffpY  
} .C &kWM&j  
d`C$vj  
X|/RV4x@Cq  
private void processErrorCode(int nErrorCode) gK(G1  
{ }p-/R'  
System.err.println("Error Code : " + nErrorCode); `.dwG3R  
} rqnxRq  
+0j{$MPZ  
j8 `7)^  
//停止文件下载 _n!>*A!  
public void siteStop() )v*k\:Hw  
{ $06('Hg&  
bStop = true; US=K}B=g  
for(int i=0;i<nStartPos.length;i++) OCJt5#e~A  
fileSplitterFetch.splitterStop(); ?m+];SJk  
O*bzp-6\  
R'6(eA[K  
}  (:o:_U  
} >8x)\'w  
//负责部分文件的抓取 /R?[/`)f&  
**FileSplitterFetch.java %#PWD7a\  
*/ P-$ ,  
package NetFox; = Ezg3$%-  
U;*t5l  
lrwQ >N  
import java.io.*; <Rs$d0/  
import java.net.*; S:Jg#1rww-  
){z#Y#]dP  
Iz83T9I&  
public class FileSplitterFetch extends Thread { MxUbx+_N  
l_$>$d  
ixK9/5T  
String sURL; //File URL Mk=*2=d  
long nStartPos; //File Snippet Start Position 'Z=_zG/RX  
long nEndPos; //File Snippet End Position H=*0KX{  
int nThreadID; //Thread's ID 5''k|B>  
boolean bDownOver = false; //Downing is over `HnZ{PKf  
boolean bStop = false; //Stop identical ]Hq,Pr_+  
FileAccessI fileAccessI = null; //File Access interface @o*~\E<T  
jcvq:i{  
+'iqGg-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4}t&yu<P>  
{ K7.ayM 0  
this.sURL = sURL; =R 4]Kf  
this.nStartPos = nStart; kOdpW  
this.nEndPos = nEnd; OwPHp&{ Y  
nThreadID = id; auX(d -m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _V e)M%  
} b<#zgf  
b/JjA  
(3Xs  
public void run() i%F2^R@!q/  
{ :is2 &-|x  
while(nStartPos < nEndPos && !bStop) EE|c@M^  
{ zBwqIJfM  
<HTz  
K>LS8,8V  
try{ R]Z#VnL@qz  
URL url = new URL(sURL); nT2b"wkTT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Nu3IYS5&  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]bmf}&  
String sProperty = "bytes="+nStartPos+"-"; d0|{/4IWw;  
httpConnection.setRequestProperty("RANGE",sProperty); 0-aaLC~Z>  
Utility.log(sProperty); 0S4Y3bac&  
Z%LS{o~LK.  
u rQvJ  
InputStream input = httpConnection.getInputStream(); E BoC,{R#  
//logResponseHead(httpConnection); jk_yrbLc  
d8R|0RZ  
uPN^o.,/.  
byte[] b = new byte[1024]; uHbbPtk  
int nRead; e]ST0J"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1M?x,N_W  
{ ]]`[tVaFr  
nStartPos += fileAccessI.write(b,0,nRead); 1:M'|uc  
//if(nThreadID == 1) 23K#9!3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >gq=W5vN(  
} |0>rojMq  
$sb@*K}:4  
$7xfLS8Vo  
Utility.log("Thread " + nThreadID + " is over!"); dD'KP4Io@  
bDownOver = true; <;>k[P'  
//nPos = fileAccessI.write (b,0,nRead); D'{ o3Q,%K  
} sAs`O@  
catch(Exception e){e.printStackTrace ();} EV* |\ te  
} mr_NArF  
} X|g5tnsj`  
J8@+)hn  
|a /cw"  
//打印回应的头信息 j5[ >HL  
public void logResponseHead(HttpURLConnection con) f*hnzj  
{ : 4lR`%  
for(int i=1;;i++) N!v>2"x8q  
{ 'u%_Ab_H  
String header=con.getHeaderFieldKey(i); yDe*-N\'W  
if(header!=null) :x3DuQP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6 !fq658  
Utility.log(header+" : "+con.getHeaderField(header)); &Q\k`0vzVB  
else ZD$I-33W  
break; zH~g5xgh  
} " ;8kKR  
} fHI@' '0  
Sn.I{~  
u8<Fk !  
public void splitterStop() @Y(7n/*  
{ v] Xy^7?  
bStop = true; g&ba]?[A  
} )^ )|b5,  
u+jx3aP:  
eB,@oo%  
} jlUT9Zp  
\tS| N40  
H66~!J0;a  
/* ms+gq  
**FileAccess.java 0d`lugf  
*//文件访问(定位,写) *s2 C+@ef  
package NetFox; ,p..h+l  
import java.io.*; :O;uP_r9  
d+8|aS<A  
L>57eF)7  
public class FileAccessI implements Serializable{ 5y~B/.YY  
)$2h:dw_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9!D c=  
RandomAccessFile oSavedFile; 2qKAO/_O  
long nPos; 8{CBWXo$)  
_9iF`Q  
cavzXz  
public FileAccessI() throws IOException ~@D!E/hZx  
{ /"1[qT\F  
this("",0); "+4r4  
} w /CD-  
g8Zf("  
7{=+Va5  
public FileAccessI(String sName,long nPos) throws IOException *AYjMCo  
{ }iB>3|\  
oSavedFile = new RandomAccessFile(sName,"rw"); M;@/697G  
this.nPos = nPos; P?iQ{x}w~  
oSavedFile.seek(nPos);  0LUw  
} "LVN:|!  
v%Su#xq/  
byj7c(  
public synchronized int write(byte[] b,int nStart,int nLen) o7:"Sl2AD  
{ V%J_iY/BUb  
int n = -1; t~]tw  
try{ %TQ5#{Y  
oSavedFile.write(b,nStart,nLen); yrrP#F  
n = nLen; [\pp KC  
} J)=Ts({  
catch(IOException e) Be0v&Q_NK  
{ t-J\j"~%+  
e.printStackTrace (); th|TwD&mO  
} ZL- ` 3x  
xgB-m[Xi  
&uu69)u  
return n; j|(bdTZY:  
} #K[6Ai=We}  
(0bXsfe  
0]t7(P"F6  
} ~^"s.Lsb  
k|_LF[*Z  
n'Z5rXg  
/* I~U;M+n*y  
**SiteInfoBean.java [c#?@S_  
*/ EcmyY,w  
package NetFox; QU^?a~r  
Q!}LtR$  
H-Or  
public class SiteInfoBean { )u_[cEJHO  
BYsQu.N  
W q>qso  
private String sSiteURL; //Site's URL Gw}b8N6E  
private String sFilePath; //Saved File's Path ST^{?Q  
private String sFileName; //Saved File's Name $3 ~ /H"K  
private int nSplitter; //Count of Splited Downloading File l( 0:CM  
}Fgp*x-G  
yM*< BV  
public SiteInfoBean() *v9 {f?  
{//nSplitter的缺省值为5 nL-kBW Ed>  
//default value of nSplitter is 5 7e`h,e=  
this("","","",5); 3r,^is  
} sBm/9vu  
)qV&sru.$  
TP&&' 4?D1  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) d7Devs k  
{ >>HC|  
sSiteURL= sURL; ,*'aH z  
sFilePath = sPath; 2*@.hBi  
sFileName = sName; ? ;)F_aHp  
this.nSplitter = nSpiltter; lC(g&(\{  
b&Go'C{p  
"?TKz:9r  
} piKR*|F  
WL/9r *jW  
0}y-DCuQ  
public String getSSiteURL() nvnJVkL9s  
{ Qp]-4%^Vz  
return sSiteURL; _q dLA  
} :*{\oqFn~$  
`d i/nv)  
y1 53ax  
public void setSSiteURL(String value) JqYt^,,Q:  
{ [E/}-m6g  
sSiteURL = value; hz_F^gF  
} 1 |zy6  
8cyC\Rs  
|;6l1]hk6  
public String getSFilePath() qo" _w%{  
{ SR\F2@u  
return sFilePath; @n:.D9  
} v<U +&D{  
'+{dr\nJ  
GBsM?A:  
public void setSFilePath(String value) \9t6 #8  
{ %/x%hs;d  
sFilePath = value; wk"zpI7L  
} Z6vm!#\  
lm;G8IP`  
P?P))UB5  
public String getSFileName() h*GU7<F:a  
{ SMdkD]{g  
return sFileName; XUyoZl?  
} =wy3h0k^  
Z*rA~`@K6  
I^z$0  
public void setSFileName(String value) NJglONO  
{ 1"82JN|!  
sFileName = value; axW4 cS ?  
} cOr@dUSL  
S(f V ,;Z  
?)~j>1"S  
public int getNSplitter() 8/y~3~A{D  
{ D< 4!7*9%  
return nSplitter; 'Na/AcRdg  
} 5vso%}c  
j>0~"A  
r2*'5jk_  
public void setNSplitter(int nCount) ^{W#ut>IN  
{ >5jHgs#  
nSplitter = nCount; h8yv:}XU*  
} y=jTS  
} Dg LSDKO!  
drQioH-  
DjT ekn  
/* {mp;^/O`er  
**Utility.java 'd"\h#  
*/ QJG]z'c+  
package NetFox; zq5_&AeW  
diLjUC`69  
Wsr #YNhx|  
public class Utility { R<!WW9IM  
N!fp;jvG  
`f:5w^A  
public Utility() A*h)p@3t<  
{ 3\,TI`^C  
Z6b3gV  
)W@H  
} tc{23Rf%  
Hc@Z7eQ3^  
//线程睡眠 uREc9z `Q'  
public static void sleep(int nSecond) #oYX0wvl  
{ Oz9k.[j(  
try{ >NE]TZ.F  
Thread.sleep(nSecond); 55oLj.l^j  
} q\[31$i$  
catch(Exception e) ,gU9y wg  
{ <MN+2^ed&  
e.printStackTrace (); XEZ6%Q_  
} 7l Aa6"Y68  
} gzDb~UEoF  
"VWxHRVg4M  
//日志 {\t:{.F A  
public static void log(String sMsg) JoZC+G  
{ Smk]G))o{  
System.err.println(sMsg); LM _4.J  
} !*%3um  
,)L.^<  
[uRsB5  
public static void log(int sMsg) >[xQUf,p  
{ PJ Air8  
System.err.println(sMsg); c_^H;~^rL  
} @V:b Co  
} o7 !@WOeZ3  
dm$:xE":  
72-@!Z0e  
/* Fr%KO)s2  
**TestMethod.java I )B2Z(<Q  
*/ *pasI.2s#  
package NetFox; A)7'\JK7b  
QW2% Gv:  
TU. h  
public class TestMethod { C1G Wi4)  
FpRK^MEkG  
m d C. FO-  
public TestMethod() NM]6  o  
{ ///xx/weblogic60b2_win.exe d&'6l"${  
try{ *gT TI;:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F37,u|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U3U eTa_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ac&tpvij  
fileFetch.start(); HRw,D=  
} E_yh9lk  
catch(Exception e){e.printStackTrace ();} YT:5J%"  
ng 6G<hi  
i([A8C_A  
} fg1 zT~  
|n &6z  
)US) -\^  
public static void main(String[] args) a,tP.Xsl  
{ (Pu*[STTT  
new TestMethod(); ):[[Ch_  
} n+i}>3'A  
} 54)}^ftY^  
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