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http断点续传简单实现(java)

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/* jFb?b6b  
**SiteFileFetch.java |nF8gh~}  
*/ B1Oq!k  
package NetFox; *|l/6!WM  
import java.io.*; U ;I9 bK8  
import java.net.*; YoE3<[KD(  
-.3w^D"l  
uVU)d1N  
public class SiteFileFetch extends Thread { qY#6SO`_iy  
k_R"CKd  
Qci]i)s$js  
SiteInfoBean siteInfoBean = null; //文件信息Bean @lt#Nz  
long[] nStartPos; //开始位置 3N:D6w-R  
long[] nEndPos; //结束位置 3ANQaUC  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :i7;w%B  
long nFileLength; //文件长度 R GX=)  
boolean bFirst = true; //是否第一次取文件 *owU)  
boolean bStop = false; //停止标志 E!AE4B1bd  
File tmpFile; //文件下载的临时信息 S@sO;-^+  
DataOutputStream output; //输出到文件的输出流 kNL\m[W8$  
L.WljNo  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ]cruF#`%  
public SiteFileFetch(SiteInfoBean bean) throws IOException w*MpX U<  
{ |WUG}G")*x  
siteInfoBean = bean; Lh<).<S  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); KY N0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0|b>I!_"g  
if(tmpFile.exists ()) D,ln)["xm  
{ FCn_^l)EA  
bFirst = false; K4);HJ|=  
read_nPos(); snikn&  
} Ic4H#w  
else m#F`] {  
{ sT' 5%4  
nStartPos = new long[bean.getNSplitter()];  f V(J|  
nEndPos = new long[bean.getNSplitter()]; +'w3 =2Bo  
} g zg_>2Sj  
FsryEHz  
Qw)c$93  
k;L6R!V  
} -PQv ?5  
d^6M9lGU  
I!?}jo3  
public void run() '`<w#z}AF  
{ PiYxk+N  
//获得文件长度 N.{D$"  
//分割文件 8&aq/4:q0  
//实例FileSplitterFetch \'bzt"f$j  
//启动FileSplitterFetch线程 (!N|Kl  
//等待子线程返回 0K2`-mL  
try{ WeiFmar  
if(bFirst) ?3xzd P  
{ t<viX's  
nFileLength = getFileSize(); nj53G67y  
if(nFileLength == -1) # Vha7  
{ }AH] th  
System.err.println("File Length is not known!"); 1y4  
} 3Ims6I]  
else if(nFileLength == -2) LE>]8[ f6S  
{ :[!j?)%>  
System.err.println("File is not access!"); {> 0wiH#!E  
} 'X2POay1  
else \} :PLCKT  
{ d;}nh2*  
for(int i=0;i<nStartPos.length;i++) tC9n k5~  
{ igR";OQk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /Mu @,)''  
} /RC7"QzL  
for(int i=0;i<nEndPos.length-1;i++) sp*v?5lW  
{ NPe%F+X  
nEndPos = nStartPos[i+1]; \)?HJ  
} 7VFLJr t  
nEndPos[nEndPos.length-1] = nFileLength; hFl^\$Re  
} ITT@,  
} n#OB%@]<V  
<<R*2b  
r|Tcfk]%  
//启动子线程 r? E)obE  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; s6^>F/x  
for(int i=0;i<nStartPos.length;i++) ~1vDV>dpE  
{ *itUWpNhr  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }2<7%FL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ` v@m-j6  
nStartPos,nEndPos,i); [e}]}t8m  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @7j AL-  
fileSplitterFetch.start(); K}MK<2vU  
} h|{]B,.Lh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JHTSUq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q|?L*Pq2I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l3I:Q^x@  
nEndPos = " + nFileLength); zsyIV!(  
// fileSplitterFetch[nPos.length-1].start(); @8r pD"x  
aH/ k Ua  
j yUCH*@  
//等待子线程结束 ;P%1j|7  
//int count = 0; AogVF  
//是否结束while循环 9H`XeQ.  
boolean breakWhile = false; *]/zc1Q4M  
]R f[y  
'=8d?aeF  
while(!bStop) ofw3S |F6  
{ LR.<&m%~.  
write_nPos(); CSq4x5!_7>  
Utility.sleep(500); 70tH:Z)"  
breakWhile = true; >rKIG~P_  
j0evq+  
;LSANr&  
for(int i=0;i<nStartPos.length;i++) co|aC!7  
{ ywm8N%]v  
if(!fileSplitterFetch.bDownOver) .Una+Z  
{ !1 H# 6  
breakWhile = false; W^LY'ypT  
break; Z!zF\<r  
} f=gW]x7'R+  
} J({Xg?  
if(breakWhile) iYm-tsER;  
break; tKx~1-  
Nk VK  
n QZwC  
//count++; FX`>J6l:X  
//if(count>4) `yXg{lk  
// siteStop(); e95Lo+:f  
} j<jN05p  
d#rf5<i  
f:|1_j  
System.err.println("文件下载结束!"); u^bidd6JRn  
} QIvVcfM^  
catch(Exception e){e.printStackTrace ();} hl(hJfp  
} ju8q?Nyhs  
u jq=F  
0c'<3@39k|  
//获得文件长度 )E@.!Ut4o  
public long getFileSize() i&66Fi1  
{ >j(_[z|v3  
int nFileLength = -1; `nv~NLkl  
try{ 7#ibN!  
URL url = new URL(siteInfoBean.getSSiteURL()); #9}D4i.`}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); aweV#j(y  
httpConnection.setRequestProperty("User-Agent","NetFox"); T?soJ]A  
JG!mc7  
z.9U}F  
int responseCode=httpConnection.getResponseCode(); R_ ,UMt  
if(responseCode>=400) M!A}NWF  
{ kmsb hYM)  
processErrorCode(responseCode); iWB=sL&p  
return -2; //-2 represent access is error NI}yVV  
} [.'|_l  
QP^Cx=  
bv9i*]  
String sHeader; otl0J Ht*+  
UkT=W!cq  
|\<`Ib4j  
for(int i=1;;i++) [.8BTj1%  
{ }=UHbU.n~!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); fk[-mZ  
//Utility.log(in.readLine()); o"Euwh!!  
sHeader=httpConnection.getHeaderFieldKey(i); c~$)UND^  
if(sHeader!=null) fc%xS7&  
{ *:YiimOY"  
if(sHeader.equals("Content-Length")) ~xfP:[u  
{ WJndoB.f[2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Lh"<XYY  
break; /vde2.|  
} 3n1;G8Nf  
} F/bT)QT<f  
else ^ f &XQQY  
break; :q7Wy&ow  
} =wHVsdNCN  
} *_{j=sd  
catch(IOException e){e.printStackTrace ();} !t %j?\f  
catch(Exception e){e.printStackTrace ();}  u\x}8pn  
V>%rv'G8  
}bpQq6ZF  
Utility.log(nFileLength); }DE g-j,F  
%@ODs6 R0  
y$F'(b| )  
return nFileLength; !/*\}\'4  
} 3!Ij;$  
-M~:lK]n   
%lx!. G  
//保存下载信息(文件指针位置) u+e{Mim  
private void write_nPos() qu6D 5t  
{ N1S{suic  
try{ ksqQM  
output = new DataOutputStream(new FileOutputStream(tmpFile)); UA0Bzoky;  
output.writeInt(nStartPos.length); 2K6qY)/_  
for(int i=0;i<nStartPos.length;i++) #7 $ H  
{ B6As,)RjD:  
// output.writeLong(nPos); R)( T^V`{  
output.writeLong(fileSplitterFetch.nStartPos); K5VWt)Z#  
output.writeLong(fileSplitterFetch.nEndPos); >`mVY=H i  
} F>6|3bOR  
output.close(); sPQQ"|wU  
} $}q23  
catch(IOException e){e.printStackTrace ();} \?ZB]*Fu  
catch(Exception e){e.printStackTrace ();} YnS#H"  
} Y%aCMP9j~9  
#PW9:_BE  
TG?brgW  
//读取保存的下载信息(文件指针位置) $q{!5-e  
private void read_nPos() f=Gg9bnm3  
{ syj0.JD  
try{ t?&|8SId  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); El".I?E*  
int nCount = input.readInt(); KVaiugQ   
nStartPos = new long[nCount]; r~8 $1"  
nEndPos = new long[nCount]; dNH08q8P  
for(int i=0;i<nStartPos.length;i++) ]t,BMu=%  
{ (9 GWbB?  
nStartPos = input.readLong(); \<>ih)J@tt  
nEndPos = input.readLong(); {.|CdqwY  
} ^_W#+>&--  
input.close(); Tc:)- z[o  
} 8z`G,qh  
catch(IOException e){e.printStackTrace ();} fc3{sZE2M  
catch(Exception e){e.printStackTrace ();} |O+H[;TB6  
} 3m)0z{n  
\fd v]f  
6]N;r5n  
private void processErrorCode(int nErrorCode) fu ,}1Mq#  
{ 1{. |+S Z!  
System.err.println("Error Code : " + nErrorCode); nEy&>z  
} ]Sz:|%JP1  
Yn Mvl  
yYYSeH  
//停止文件下载 At>DjKx]O  
public void siteStop() g%I"U>!2  
{ g2ixx+`?|:  
bStop = true; m,w A:o$'  
for(int i=0;i<nStartPos.length;i++) h"Q8b}$^)  
fileSplitterFetch.splitterStop(); #L;dI@7C  
q!7ANib6O  
}C?'BRX  
} <2x^slx)?  
} itP,\k7>d  
//负责部分文件的抓取 R| , g<  
**FileSplitterFetch.java >T-u~i$s  
*/ ]p GL`ge5  
package NetFox; b\!_cb~"@  
]:-mbgW  
& h)yro  
import java.io.*; hWLA<wdb  
import java.net.*; ZvX*t)VjTz  
8/cX]J  
G j?t_Zln  
public class FileSplitterFetch extends Thread { BwpqNQN  
cwlRQzQ(  
xm~`7~nFR  
String sURL; //File URL @b%=H/5\  
long nStartPos; //File Snippet Start Position !>o7a}?  
long nEndPos; //File Snippet End Position lfgq=8d  
int nThreadID; //Thread's ID Q&tG4f<  
boolean bDownOver = false; //Downing is over o:'MpKm  
boolean bStop = false; //Stop identical r Z$O?K  
FileAccessI fileAccessI = null; //File Access interface v!-pSa)3  
pah'>dAL  
Ge@{_  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException SKN`2hD  
{ ^z*t%<@[Q  
this.sURL = sURL; Dx?,=~W9  
this.nStartPos = nStart; Q3~H{)[Kq  
this.nEndPos = nEnd; ,[KD,)3y  
nThreadID = id; t{9GVLZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #zs~," dRv  
} ;igIZ$&  
vA{-{Q  
.~;\eW[  
public void run() Sz`,X0a  
{ $a]`nLUa  
while(nStartPos < nEndPos && !bStop) !f [_+CD  
{ 'IQ0{&EI  
(ZZ8L-s  
tDcT%D {:  
try{ ED gag  
URL url = new URL(sURL); (?c"$|^J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T!#GW/?  
httpConnection.setRequestProperty("User-Agent","NetFox"); UI0VtR]   
String sProperty = "bytes="+nStartPos+"-"; 7JH6A'&  
httpConnection.setRequestProperty("RANGE",sProperty); 6nvz8f3*r]  
Utility.log(sProperty); ouQ T  
03Ycf'W  
f$$/H>MJ  
InputStream input = httpConnection.getInputStream(); g! |kp?  
//logResponseHead(httpConnection); 0{D'n@veP  
rb.N~  
!F$6-0%  
byte[] b = new byte[1024]; x 9fip-  
int nRead;  =:pJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b4kgFA  
{ I\ob7X'Xu!  
nStartPos += fileAccessI.write(b,0,nRead); {EQOP]  
//if(nThreadID == 1) W${Ue#w77  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )ez9"# MH'  
} <bWG!ZG  
PJH&  
GD$l| |8  
Utility.log("Thread " + nThreadID + " is over!"); q2E_ A  
bDownOver = true; y<Ot)fa$  
//nPos = fileAccessI.write (b,0,nRead); %h!B^{0  
} zrb}_  
catch(Exception e){e.printStackTrace ();} NBGH_6DROw  
} {P_.~0pc*  
} )SGq[B6@I  
xy;;zOh`  
4kx N<]  
//打印回应的头信息 rey!{3U  
public void logResponseHead(HttpURLConnection con) ? =Kduef  
{ Km$\:Xo  
for(int i=1;;i++) JWxwJex  
{ NzvXN1_%  
String header=con.getHeaderFieldKey(i); ww1[rCh\+  
if(header!=null) -iZ`Y?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); OneY_<*a<  
Utility.log(header+" : "+con.getHeaderField(header)); [ 4)F f  
else `ERz\`d~Y;  
break; S f# R0SA  
} X &H"51  
} ?:0Jav  
8quaXVj^a  
|FRg\#kf%  
public void splitterStop() 8}:nGK|kx  
{ -Q Nh  
bStop = true; ]`WJOx4  
} z F;K  
?S=mybp  
4*;MJ[|  
} >vsqG=x  
m1AJ{cs  
mt.))#1  
/* <#4h}_xA%  
**FileAccess.java )4;`^]F  
*//文件访问(定位,写) r3?o9D>  
package NetFox; qH_Dc=~la  
import java.io.*; >9J:Uo1z  
BZ^}J!Q'*  
veECfR;  
public class FileAccessI implements Serializable{ I]q% 2ie  
'|=;^Z7.K  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 A3*!"3nU  
RandomAccessFile oSavedFile; 2X&qE}%k S  
long nPos; hi[pVk~B)  
j] [,J49L  
xgtR6E^k  
public FileAccessI() throws IOException I%Z  
{ 3G4-^hY<  
this("",0); BJ(M2|VH  
} |4`{]2C  
w4Z'K&d=  
1h5 Akq  
public FileAccessI(String sName,long nPos) throws IOException 32 =z)]FZ  
{ e96k{C`j0  
oSavedFile = new RandomAccessFile(sName,"rw"); ^<AwG=  
this.nPos = nPos; Oow2>F%_#  
oSavedFile.seek(nPos); (7*}-Uy[C  
} v &+R^iLE  
$ME)#(  
/a o5FL  
public synchronized int write(byte[] b,int nStart,int nLen) ~Cjn7  
{ @lph)A Nk  
int n = -1; Ga'swP=hf  
try{ [ikOb8 G#  
oSavedFile.write(b,nStart,nLen); >o,TZc\  
n = nLen; A5w6]:f2  
} 8\gjST*  
catch(IOException e) sx<%2  
{ 1-QS~)+  
e.printStackTrace (); WuW^GC{7  
} W@!S%Y9  
@s^-.z  
F4{IEZ  
return n; @\I#^X5lv  
} m j@13$=  
VLN_w$iEq  
`y* }lg T  
} >lM l  
8HdAFRw  
1ZRT:N<-  
/* sn>~O4"  
**SiteInfoBean.java O|UC ?]6  
*/ ,6W>can  
package NetFox; WOf 4o  
#cLBQJq  
61 ~upQaR  
public class SiteInfoBean { {kAc(  
Dn}Jxu'(  
5rUdv}.  
private String sSiteURL; //Site's URL *_g$MI  
private String sFilePath; //Saved File's Path T9q-,w/j;  
private String sFileName; //Saved File's Name ;ovP$ vl>  
private int nSplitter; //Count of Splited Downloading File /,Jqmm#s^  
& "B=/-(  
HE_8(Ms ;8  
public SiteInfoBean() .XhrCi Z  
{//nSplitter的缺省值为5 0Fr?^3h  
//default value of nSplitter is 5 K'I#W lg  
this("","","",5); Q)z8PQl O  
} e<q?e}>?  
RY*U"G0#w  
i(+p0:< 0  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]]j;/TiG  
{ $ o#V#  
sSiteURL= sURL; xA[mm  
sFilePath = sPath; HiJE}V;Vq  
sFileName = sName; @!d{bQd,  
this.nSplitter = nSpiltter; fa2kG&, _  
$]2vvr  
mU9kVx1+  
} ?#Q #u|~  
ib791  
-+-_I*(  
public String getSSiteURL() SOvF[,+  
{ Lbb0_-']  
return sSiteURL; Ef13Q]9|  
} Hg (Gl  
-1ub^feJ,  
|)/aGZ+  
public void setSSiteURL(String value) 4]}'Hln*U  
{ )TM4R)r%)9  
sSiteURL = value; NSA-}2$  
} y Fq&8 x<X  
2Q:+_v  
Fh9h,' V"  
public String getSFilePath() ^@NU}S):yN  
{ g5r(>,vY  
return sFilePath; _ZkI)o  
} .y:U&Rw4  
=kG@a(-  
x;<W&s}(  
public void setSFilePath(String value) 3>VL}Ui}  
{ 2WYPO"q  
sFilePath = value; *% @h(js  
} >`ZyG5  
4d;8`66O  
A1zjPG&]  
public String getSFileName() Hc(OI|z~  
{ fPW@{~t  
return sFileName; [Hh9a;.*}h  
} $5Ff1{  
W-zP/]Dh  
_b;{_g  
public void setSFileName(String value) %&t<K3&Yh  
{ xe&i^+i  
sFileName = value; PBkt~=j  
} &H:(z4/  
vn"{I&L+w0  
'$zIbQ:  
public int getNSplitter() R`^_(yn>  
{ ,]c 1A$Sr0  
return nSplitter; {o`] I>gb  
} M?uC%x+S$_  
(,Df^4%7  
3HY9\'t6  
public void setNSplitter(int nCount) :'*~uJrR  
{ i9][N5\$  
nSplitter = nCount; q;>7*Y&  
} #';:2Nyq  
} K~eh P[^  
0T5L_%c  
AoL2@C.C%D  
/* IG9VdDj  
**Utility.java ?R.j^ S^  
*/ M%;hB*9  
package NetFox; Lrq .Ab#  
a]tVd#  
/,Re "!jh  
public class Utility { xLH)P<^`C  
L"*/:$EJL.  
,0HRAmG  
public Utility() ` 3K)GA  
{ 2Gaa(rJ5o  
u-G+ j)  
pYZ6e_j1 ~  
} % 0+j?>#X  
=CVBBuVy  
//线程睡眠 ]R9HyCl&a6  
public static void sleep(int nSecond) _#8RSr8'y  
{ !s?nJ(p  
try{ o@i#|kx,  
Thread.sleep(nSecond); 3Xy-r=N.l  
} Z+. '>  
catch(Exception e) JB]q   
{ ly_HWuFJ3  
e.printStackTrace (); g0Gf6o>2  
} _k ~KZ;l  
} I5n^,@md  
A='N=^Pm  
//日志 8=uu8-l8g  
public static void log(String sMsg) EkNunCls  
{ 3e;^/kf<9  
System.err.println(sMsg); .Blf5b  
} kbMWGB%;  
fd<:_f]v  
(w/T-*  
public static void log(int sMsg) k" PayyAC  
{ (I{rLS!o,L  
System.err.println(sMsg); # ,_u_'C*!  
} +:!7L= N#  
} MUREiL9L|  
jun_QiU:2  
,*hLFaR-  
/* D"rK(  
**TestMethod.java *><F'   
*/ ;=; 9tX  
package NetFox; .e=:RkI,  
LzXmb 7A  
D rHV G  
public class TestMethod { p#?7 w  
[~#WG/!:  
*|C^=*j9  
public TestMethod() kG@@ot" n  
{ ///xx/weblogic60b2_win.exe =Og)q$AL  
try{ jW3!6*93  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); * @v)d[z_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); T| V:$D'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >qjq=Ege  
fileFetch.start(); 9m<jcxla$  
} dx &'fe*?  
catch(Exception e){e.printStackTrace ();} o9%)D<4M  
f~y%%+{p  
iAa.}CI,zB  
} Dhw(#{N  
3z)Kz*xr  
Ax?y  
public static void main(String[] args) v7jq@#-   
{ D!NQ~'.a=2  
new TestMethod(); ,)Ju[  
} ^~@U]  
} 57zSu3v4Y  
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