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http断点续传简单实现(java)

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/* A]nDI:pO|  
**SiteFileFetch.java IyE9G:fY  
*/ l\l\T<wa,  
package NetFox; &HKrmFgX{  
import java.io.*; =Ewa}$-  
import java.net.*; N"~P` H![x  
)4[{+OJa  
h~$Q\WCm#  
public class SiteFileFetch extends Thread { Xg#g`m%(M  
fT.5@RR7^  
&Vi"m!Bf  
SiteInfoBean siteInfoBean = null; //文件信息Bean rnxO2   
long[] nStartPos; //开始位置 UQz8":#V  
long[] nEndPos; //结束位置 QsYc 9]:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 k|l"Rh<\~  
long nFileLength; //文件长度 AR\1w'  
boolean bFirst = true; //是否第一次取文件 UP:+1Sp9  
boolean bStop = false; //停止标志 g5TXs^g  
File tmpFile; //文件下载的临时信息 BY: cSqAW  
DataOutputStream output; //输出到文件的输出流 6 USet`#  
wxPg*R+t  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ~AuvB4xe~  
public SiteFileFetch(SiteInfoBean bean) throws IOException T8YqCT"EA<  
{ )_EQU8D4ug  
siteInfoBean = bean; n15c1=gs  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WPyd ^Y<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?,|_<'$4T  
if(tmpFile.exists ()) Zl"h-~31  
{ >fo &H_a  
bFirst = false; ;D]TPBE  
read_nPos(); ;3'}(_n  
} J8a4.prqI  
else >'^l>FPc  
{ e,I-u'mLQs  
nStartPos = new long[bean.getNSplitter()]; N|q:wyS|  
nEndPos = new long[bean.getNSplitter()]; s@o"V >t  
} )@Xdr0  
Y_PCL9G{p  
]@ETQ8QN  
sr#, S(p  
} Q}]:lmqH  
#:Cr'U  
C bG"8F|4  
public void run() @]*z!>1  
{ a|?CC/Ra  
//获得文件长度 hU G Iy(  
//分割文件 7"4|`y^#  
//实例FileSplitterFetch x)#k$ QU  
//启动FileSplitterFetch线程 1aYO:ZPy  
//等待子线程返回 9>@_};l  
try{ v}[KVwse  
if(bFirst) 40%p lNPj  
{ {yVi/*;f^  
nFileLength = getFileSize(); hPFIf>%}  
if(nFileLength == -1) dJNYuTZ'  
{ 5bmtUIj  
System.err.println("File Length is not known!"); ,\}V.:THF  
} XfbkK )d  
else if(nFileLength == -2) 0?,EteR  
{ #C%<g:F8  
System.err.println("File is not access!"); aKCCFHq t!  
} %I Y-0\  
else !h9 An  
{ AW> P\>{RE  
for(int i=0;i<nStartPos.length;i++) by6E "7%  
{ {2Gp+&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); wZrdr4j  
} %t+V8A  
for(int i=0;i<nEndPos.length-1;i++) ,PN>,hFL  
{ UQW;!8J#R(  
nEndPos = nStartPos[i+1]; 5-u=ZB%p  
} I8^z\ef&  
nEndPos[nEndPos.length-1] = nFileLength; sMO3eNLn  
} ]s, T` (&  
} -QS_bQG%  
)sNtw Sl^  
miN(a; Q2P  
//启动子线程 )_bXKYUX*0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; iQa Q"s  
for(int i=0;i<nStartPos.length;i++) X#eVw|  
{ \D}/tz5~B  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @~gz-l^$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wRie{Vk  
nStartPos,nEndPos,i); ;#xhlR* ~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9@vY(k k  
fileSplitterFetch.start(); VCc4nn#  
} dd4yS}yBlR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,hOJe=u46  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); D]oS R7h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @&M $`b ^  
nEndPos = " + nFileLength); ;UPw;'  
// fileSplitterFetch[nPos.length-1].start(); >J8?n,*  
_r,# l5~U  
i!,>3  
//等待子线程结束 m&ZdtB|  
//int count = 0; n!tCz<v  
//是否结束while循环 $ \P!P.  
boolean breakWhile = false; ,:z@Ji  
uNx3us-  
TS1 k'<c?  
while(!bStop) Jn:GqO  
{ 'x6Mqv1W  
write_nPos(); E|^a7-}|  
Utility.sleep(500); !Sw7!h.ut  
breakWhile = true; ;2X1qw>  
a>Q7Qn  
}D|"$*  
for(int i=0;i<nStartPos.length;i++) TAGqRYgi  
{ myJsRb5  
if(!fileSplitterFetch.bDownOver) ="I]D I  
{ 8\ :T*u3  
breakWhile = false; !J6k\$r  
break; K): )bL(B  
} N:&Gv'`  
} ]AfeaU'>  
if(breakWhile) 12rr:(#%s  
break; nq$^}L3&~  
-EL"Sv?  
f:BW{Cij;y  
//count++; $T*kpUXH}  
//if(count>4) 2 K` hH  
// siteStop(); Li7/pUq>}!  
} @h$7C<  
>+G=|2  
O"{NHNG\oT  
System.err.println("文件下载结束!"); 7W 4[1  
} Wk$%0xZ7  
catch(Exception e){e.printStackTrace ();} Z4rK$ B  
} #&$4tTl  
3 i>uKU1  
ThFI=K  
//获得文件长度 :@n e29,}  
public long getFileSize() t/nu/yz5E  
{ JZai{0se  
int nFileLength = -1; %40|7 O  
try{ |*8 J.H*r  
URL url = new URL(siteInfoBean.getSSiteURL()); '{ C=vW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r_ Xk:  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5 kQC  
QhN5t/Hr  
;[%AeN5W  
int responseCode=httpConnection.getResponseCode(); [x9eamJ,H  
if(responseCode>=400) XFH7jHnL+U  
{ ?L7z\b"_~  
processErrorCode(responseCode); P PmE.%_  
return -2; //-2 represent access is error tX6n~NJ$  
} d+z8^$z"  
 Q L  
fF<~2MiKw  
String sHeader; ~kF^0-JZY  
i?||R|>;"'  
dTS 7l02  
for(int i=1;;i++) td{$ c6  
{ W!htCwnkF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *<]ulR2  
//Utility.log(in.readLine()); ,uK }$l  
sHeader=httpConnection.getHeaderFieldKey(i); _@SC R%  
if(sHeader!=null) Un@dWf6'  
{ X`#vH8  
if(sHeader.equals("Content-Length")) {0QNqjue  
{ arET2(h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _KLKa/3  
break; g \&Z_  
} (jtrQob  
} M;-PrJdyt  
else xrf z-"n4  
break; 4Zo.c* BZ  
} <0T|RhbY   
} 5$d>:" >  
catch(IOException e){e.printStackTrace ();} }k~ih?E^s  
catch(Exception e){e.printStackTrace ();} J<yt/V]  
Jx!#y A;  
ot($aY,t  
Utility.log(nFileLength); Kejp7 okb  
#~BsI/m  
f; w\k7 #  
return nFileLength; kNR -eG  
} @>cz$##`  
u%!/-&?wF  
k#liYw I  
//保存下载信息(文件指针位置) T\?$7$/V  
private void write_nPos() XXPn)kmWR  
{ 9kHVWDf  
try{ %<8`(Uu5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); HCfme<'  
output.writeInt(nStartPos.length); xsu9DzPf&{  
for(int i=0;i<nStartPos.length;i++) %;_94!(hC  
{ GZH{"_$  
// output.writeLong(nPos); KW-GVe%8f  
output.writeLong(fileSplitterFetch.nStartPos); ,4:=n$e 0  
output.writeLong(fileSplitterFetch.nEndPos); /s*.:cdH  
} Kv0V`}<Yc  
output.close(); 4Hy/K^Ci  
} 6S`0<Z;;/  
catch(IOException e){e.printStackTrace ();} ~(nc<M[  
catch(Exception e){e.printStackTrace ();} P q0 %oz  
} vMd3#@  
UodBK7y  
V6Mt;e)C  
//读取保存的下载信息(文件指针位置) &hEn3u  
private void read_nPos() *4/FN TC  
{ HS[($  
try{ :of(wZa3Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?4A/?Z]ub  
int nCount = input.readInt(); o?Aj6fNY?  
nStartPos = new long[nCount]; m _cRK}>  
nEndPos = new long[nCount]; _Jy7` 4B.  
for(int i=0;i<nStartPos.length;i++) 2n)?)w]!M  
{ 85YUqVi9  
nStartPos = input.readLong(); z',Fa4@z  
nEndPos = input.readLong(); ],_+J *  
} )adV`V%=>  
input.close(); N_I KH)  
} s$).Z(6  
catch(IOException e){e.printStackTrace ();} ,DZvBS  
catch(Exception e){e.printStackTrace ();} ]} dQ~lOE  
} m8ts!6C  
3/>7b (  
Q_U.J0  
private void processErrorCode(int nErrorCode) CHsg2S  
{ jMgXIK\  
System.err.println("Error Code : " + nErrorCode); RN[I%^$"  
} 12a`,~  
L8 L1_  
/M_$4O;*@  
//停止文件下载 @^xtxtjzux  
public void siteStop() &W,jR|B  
{ z@yTkH_  
bStop = true; )V\@N*L`ik  
for(int i=0;i<nStartPos.length;i++) 6Q^~O*cw  
fileSplitterFetch.splitterStop(); ikW[lefTq  
_p^ "l2%D/  
Zge(UhZ  
} <.Ws; HN}  
} Iko]c_W0  
//负责部分文件的抓取 O2?C *  
**FileSplitterFetch.java 'v"=   
*/ Nob(D'vSr  
package NetFox; } o%^ Mu B  
j{@6y  
^U }k   
import java.io.*; c2y,zq|H  
import java.net.*; mHxR4%i5  
}d<R 5  
U[@y 8yN6M  
public class FileSplitterFetch extends Thread { qhEv6Yxfw6  
w G%W{T$  
p49]{2GXb  
String sURL; //File URL T3X'73M  
long nStartPos; //File Snippet Start Position FEaT}/h;  
long nEndPos; //File Snippet End Position 5~L]zE  
int nThreadID; //Thread's ID m Qj=-\p  
boolean bDownOver = false; //Downing is over Ao\xse{E  
boolean bStop = false; //Stop identical uM-,}7f7  
FileAccessI fileAccessI = null; //File Access interface .T| }rB<c  
n0xGIq  
*MP.YI:h  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException S#7YJ7 K"N  
{ LQ jbEYp  
this.sURL = sURL; |A8@r&   
this.nStartPos = nStart; +0'F@l  
this.nEndPos = nEnd; o~Se[p  
nThreadID = id; 8xAV[i  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 K^Awf6%  
} !@xO]Jwv  
l~c[}wv  
NRi5 Vp2=  
public void run() &*C5Nnlv  
{ kZ40a\9 Ye  
while(nStartPos < nEndPos && !bStop) /jY u-H+C  
{ WYP;s7_  
#b/qR^2qW  
0MG>77  
try{ UUah5$Iy  
URL url = new URL(sURL); d1b] +AG4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D|]BFu)F  
httpConnection.setRequestProperty("User-Agent","NetFox"); _BczR:D*  
String sProperty = "bytes="+nStartPos+"-"; [q <'ty  
httpConnection.setRequestProperty("RANGE",sProperty); KZm&sk=QM-  
Utility.log(sProperty); vg z`+Zj*S  
3H,E8>Vd  
,,H"?VO  
InputStream input = httpConnection.getInputStream(); OQVrg2A%(  
//logResponseHead(httpConnection); hAGHb+:  
(]|h6aI'}  
g@.$P>Bh  
byte[] b = new byte[1024]; h9vcN#22D  
int nRead; )!T~l(g  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) | f#wbw  
{ zM'eqo>!c>  
nStartPos += fileAccessI.write(b,0,nRead); ]%Q!%uTh  
//if(nThreadID == 1) LP<A q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q;h.}N8W  
} D /eH~  
Shn,JmR  
|VfEp  
Utility.log("Thread " + nThreadID + " is over!"); %y1!'R:ZW  
bDownOver = true; gP^2GnjHL8  
//nPos = fileAccessI.write (b,0,nRead); 0-. d{P  
} @u~S!(7.Wi  
catch(Exception e){e.printStackTrace ();} -YRIe<}E -  
} Z;BS@e  
} Gp"GTPT{  
bJ^JK  
zWsr|= [  
//打印回应的头信息 h$cm:uks  
public void logResponseHead(HttpURLConnection con) 5&]5*;BvJ  
{ @"@a70WHk  
for(int i=1;;i++) 96=<phcwN[  
{ ]hl*6  
String header=con.getHeaderFieldKey(i); Y.:R-|W  
if(header!=null) iD^,O)b  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); SI(f&T(  
Utility.log(header+" : "+con.getHeaderField(header));  Fr%#  
else O-iE0t  
break; <p@Cx  
} .RD<]BxJ  
} NOb`)qb  
f/Gx}x=  
v.0qE}' |  
public void splitterStop() "c^!LV  
{ '&>"`q  
bStop = true; 8K%N7RL|  
} GP:<h@:798  
k.J%rRneN  
XLh)$rZ  
} Q>niJ'7WF  
( ?FH`<  
$vn6%M[  
/* Psb !Z(  
**FileAccess.java I-#H+\S  
*//文件访问(定位,写) {X{R]  
package NetFox; WQ|:TLQ  
import java.io.*; r )|3MUj  
dFg>uo  
`Rq=:6U;3  
public class FileAccessI implements Serializable{ -4Qub{Uym  
bM W|:rn  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Ee>VA_ss  
RandomAccessFile oSavedFile; XF`2*:7  
long nPos; b?wrOS  
h>Kx  
]m1fo'  
public FileAccessI() throws IOException 5Cf!NNV  
{ unDW2#GX  
this("",0); X9>fE{)!  
} @N'n>8Wn  
Bfb~<rs[  
2=cx`"a$  
public FileAccessI(String sName,long nPos) throws IOException y<`5  
{ <,vIN,Kl8/  
oSavedFile = new RandomAccessFile(sName,"rw"); 5(;Y&?k  
this.nPos = nPos; t~2oEwTm  
oSavedFile.seek(nPos); >a3m!`lq  
} ~E}kwF  
Ae5A@4  
Y;w|Fvjj+  
public synchronized int write(byte[] b,int nStart,int nLen) Omd;  
{ =4TQ*;V:  
int n = -1; 5SFr E`  
try{ Y1r$;;sH  
oSavedFile.write(b,nStart,nLen); :>-zT[Lcn  
n = nLen; w4 yrAj 2  
} #.8v[TkKq  
catch(IOException e) !Uiq3s`1T  
{ p.:651b  
e.printStackTrace (); ^^q&VL  
} M+"6VtZH  
b'4a;k!rS  
?mMM{{%(.  
return n; nD i^s{  
} '}agi.z  
]*dYX=6  
z+Xr2B  
} /gAT@Vx  
:'h$]p%  
 }$oS /bo  
/* t 7Y*/v&P(  
**SiteInfoBean.java m .++nF  
*/ tSy 9v  
package NetFox; |s3;`Nxu7  
qV=:2m10x  
0 u*a=f=  
public class SiteInfoBean { 8T+9 fh]I  
9]Jv >_W*  
cvcZ\y  
private String sSiteURL; //Site's URL l]G iz&  
private String sFilePath; //Saved File's Path H*]Vs=1  
private String sFileName; //Saved File's Name A%#M#hD/  
private int nSplitter; //Count of Splited Downloading File #91^1jyMf  
P!-RZEt$  
DE.].FD'  
public SiteInfoBean() RKLE@h7[?  
{//nSplitter的缺省值为5 )\yK61aX  
//default value of nSplitter is 5 =!-}q  
this("","","",5); )4rt-_t<  
} =`x }9|[  
Cl '$*h  
{ <Gyjq  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "U^m~N9k{  
{ @QTw9,pS  
sSiteURL= sURL; lEl.'X$  
sFilePath = sPath; HGAi2+&  
sFileName = sName; YM`T"`f  
this.nSplitter = nSpiltter; N]F RL\K  
wa<k%_# M  
% PzkVs  
} A+^okT37r  
\k5"&]I3  
/"J 6``MV  
public String getSSiteURL() a/ uo)']B  
{ xc*a(v0  
return sSiteURL; e1g3a1tnWl  
} frUs'j/bZ  
x^@oY5}cr  
n UmyPQ~  
public void setSSiteURL(String value) S'5)K  
{ nrY)i_\  
sSiteURL = value; "dP-e  
} hZfj$|<  
G@/iK/>5|`  
^R:&c;&,  
public String getSFilePath() 9287&+,0r  
{ pl%!AY'oE>  
return sFilePath; |kK5:\H  
} I#xdksY  
N ;=z o-8  
%SB4_ r*<  
public void setSFilePath(String value) :+6W%B  
{  FkrXM!mJ  
sFilePath = value; ~-Kx^3(#  
} el`?:dY H  
Xr=BxBttp  
^+Nd\tp  
public String getSFileName() Y Iwa =^  
{ b 9rQQS  
return sFileName; C*ep8{B  
} i=\)[;U  
MJ ch Z  
?:3hp2k<  
public void setSFileName(String value) 27N;>   
{ HSysME1X:/  
sFileName = value; .Pj<Pe  
} R/x3+_.f  
[L2+k? *  
Bk\Y v0  
public int getNSplitter() o3hgkoF   
{ ;>mM9^Jaf  
return nSplitter; ;Tnid7:S  
} (9RfsV4^  
C0[U}Y/r2  
 "x9yb0  
public void setNSplitter(int nCount) jbipNgxkr  
{ B?i#m^S  
nSplitter = nCount; 0&s a#g2  
} +ZNOvcsV  
} T+nID@"36  
FA*$ dwp  
JrOx nxd^  
/* LH2B*8=^2  
**Utility.java %4m Nk}tyH  
*/ dvjj"F'Bf  
package NetFox; Ht;Rz*}  
uQ-GJI^t  
uX1;  
public class Utility { fYjmG[4  
IWu=z!mO  
A]!0Z:{h%  
public Utility() zEFS\nP}E  
{ E#+2)Q  
j7Fb4;o{  
0YFXF  
} eZOR{|z  
.4\I?  
//线程睡眠 f;^ +q-Q  
public static void sleep(int nSecond) : B&~q$  
{ syB pF:`-W  
try{ < 8' b  
Thread.sleep(nSecond); _jG|kjFTc  
} Zq 85q  
catch(Exception e) Oq~{HJ{  
{ y!gPBkG&3n  
e.printStackTrace (); L@GICW~  
} tV(iC~/  
} B1_9l3RM  
Gt#r$.]W?o  
//日志 +8zACs{p  
public static void log(String sMsg) VQpt1cK*  
{ 1ARtFR2C{b  
System.err.println(sMsg); HSNj  
} [T r7SU#x  
uSR%6=$  
"qq$i35x  
public static void log(int sMsg) }&=l)\e  
{ E~}H,*)  
System.err.println(sMsg); :G 5p`;hGo  
} u!D?^:u=)  
} W,[ RB  
M _< |n  
9ia&/BT7"z  
/* (E0WZ $f}  
**TestMethod.java !QwB8yK@  
*/ y`zdI_!7  
package NetFox; WDghlC6g!l  
5/P. 4<c7  
Vwp>:'Pu  
public class TestMethod { LAc60^t1  
;U4O` pZ  
RjVU m+<  
public TestMethod() gH(#<f@ZI  
{ ///xx/weblogic60b2_win.exe uB"B{:Kz  
try{ IrYj#,xJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X$;x2mz nM  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9`92 >  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z#u{th  
fileFetch.start(); w%`S>+kX&  
} O8#]7\)  
catch(Exception e){e.printStackTrace ();} r jn:E  
>uZc#Zt  
8OOAPp$%|  
} W>!:K^8]  
p,z>:3M  
C"n!mr{srt  
public static void main(String[] args) mQVlE__ub  
{ '['%b  
new TestMethod(); wclj9&k  
} |(tl a_LE  
} >.UEs 8QV  
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