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http断点续传简单实现(java)

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/* 0"z9Q\{}  
**SiteFileFetch.java wMN]~|z>  
*/ &K,i f  
package NetFox; R4d=S4 i  
import java.io.*; Tlr v={  
import java.net.*; Xch~ 1K  
.=; ;  
`Pnoxm'  
public class SiteFileFetch extends Thread { ~g t@P  
@C aG9]  
klhtKp_p  
SiteInfoBean siteInfoBean = null; //文件信息Bean F:DrX_O%  
long[] nStartPos; //开始位置 _)-o1`*-  
long[] nEndPos; //结束位置 d#wVLmKZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 q@2siI~W  
long nFileLength; //文件长度 pfI&E#:5  
boolean bFirst = true; //是否第一次取文件 I%Z  
boolean bStop = false; //停止标志 Dvln/SBk  
File tmpFile; //文件下载的临时信息  !}$$:  
DataOutputStream output; //输出到文件的输出流 TD_Oo-+\  
Wc 'H  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ySI !d|_  
public SiteFileFetch(SiteInfoBean bean) throws IOException g9F?z2^  
{ bg0Wnl  
siteInfoBean = bean; \l3h0R  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =Fl^`*n  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); T51 `oZ`  
if(tmpFile.exists ()) > Nr#O  
{ Rf 1x`wml  
bFirst = false; akQ7K  
read_nPos(); }ad|g6i`  
} ovV'VcUs  
else RG`1en  
{ i!Ga5v8n:  
nStartPos = new long[bean.getNSplitter()]; <a+Z;>  
nEndPos = new long[bean.getNSplitter()]; |Q>IrT  
} a' IdYW0  
>LuYHr  
tLmTjX .6  
teVM*-  
} 4KrL{Z+}  
T6k0>[3xf  
3+bt~J0  
public void run() Aiea\j Bv  
{ t#"Grk8Mz&  
//获得文件长度 {l >hMxij  
//分割文件 <54 S  
//实例FileSplitterFetch Y6d@h? ht  
//启动FileSplitterFetch线程 vr^qWn  
//等待子线程返回 0ZO2#>gh$  
try{ Du){rVY^d  
if(bFirst) sx<%2  
{ %~S&AE-  
nFileLength = getFileSize(); DlNX 3  
if(nFileLength == -1) igAtRX%Qx  
{ _J[P[(ab  
System.err.println("File Length is not known!"); xkR0  
} hR|MEn6KC  
else if(nFileLength == -2) >F&47Yn  
{ 1aABzB ^  
System.err.println("File is not access!"); wlmRe`R  
} {]|J5Dgfe  
else m j@13$=  
{ dcT80sOC  
for(int i=0;i<nStartPos.length;i++) */DO ex"y  
{ {1 94!S4z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0qT%!ku&  
} ?G&ikxl  
for(int i=0;i<nEndPos.length-1;i++) c[Zje7 @  
{ Z EO WO  
nEndPos = nStartPos[i+1]; Om {'1  
} dC4'{ n|7  
nEndPos[nEndPos.length-1] = nFileLength; y*h<MQ  
} 6S\8$  
} Y[S1$(K&*  
@xZR9Z8]L  
RCLeA=/N@0  
//启动子线程 ~^b/(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; u> / TE  
for(int i=0;i<nStartPos.length;i++) \5cpFj5%  
{ g$o&Udgs  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;6hOx(>`=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2)~> R  
nStartPos,nEndPos,i); 1@=po)Hnp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !5?<% *  
fileSplitterFetch.start(); =E{`^IT'R  
} da~],MN  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tFl"n;~T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &YeA:i?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", NW)1#]gg%  
nEndPos = " + nFileLength); gv{ >`AN  
// fileSplitterFetch[nPos.length-1].start(); j 1HW._G  
/|#fejPh  
W|(1Y D  
//等待子线程结束 Vs{|xG7W D  
//int count = 0; e(8Ba X _  
//是否结束while循环 /JU.?M35  
boolean breakWhile = false; Oz#{S:24M+  
d*Fj3Wkx  
<_KIK  
while(!bStop) xi; `ecqS<  
{ cPc</[x[W  
write_nPos(); -o EW:~y  
Utility.sleep(500); 5QO9Q]I#_\  
breakWhile = true; ~.lPEA %%  
_oDz-  
vgN&K@hJ  
for(int i=0;i<nStartPos.length;i++) ROZF)|l  
{ @!d{bQd,  
if(!fileSplitterFetch.bDownOver) *G 9V'9  
{ k+l b@!  
breakWhile = false; 9k[9P;"F:  
break; 8qu6.  
} n@[O|?S  
} %GIr&V4|  
if(breakWhile) `x%>8/  
break; "Os_vlapHo  
ps DetP  
u,Kly<0j  
//count++; S?BG_J6A7  
//if(count>4) 26x[X.C:  
// siteStop(); 1 I",L&S1  
} Ef13Q]9|  
&UlWCOo8  
YkQd  
System.err.println("文件下载结束!"); eO[b1]WLP  
} (0kK_k'T  
catch(Exception e){e.printStackTrace ();} @2v_pJy^  
} 2gVm9gAHUd  
2SR:FUV/  
t#eTV@-  
//获得文件长度 Hl |z</*+  
public long getFileSize() 3%=~) 7cF  
{ G'aDb/  
int nFileLength = -1; tcog'nAz  
try{ }?v )N).kW  
URL url = new URL(siteInfoBean.getSSiteURL()); )IZ~G\Ra'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hqkz^!rp  
httpConnection.setRequestProperty("User-Agent","NetFox"); \:F_xq  
_``=cc  
^@NU}S):yN  
int responseCode=httpConnection.getResponseCode(); k2UVm$}u  
if(responseCode>=400) ,U dVNA  
{ x.R4% Z  
processErrorCode(responseCode); Y% 5eZ=z  
return -2; //-2 represent access is error ZO$%[ftb  
} jdJ>9O0A,  
R]*K:~DM  
Q>1[JW{$}  
String sHeader; KL Xq\{X  
[0D .K}7|  
R<N ]B  
for(int i=1;;i++) |*tp16+6  
{ k~ /Nv=D  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ( Px OE  
//Utility.log(in.readLine()); FH+s s!  
sHeader=httpConnection.getHeaderFieldKey(i); \v)+.m?n  
if(sHeader!=null) gCY';\f!  
{ v0jgki4 t  
if(sHeader.equals("Content-Length")) [QT#Yf0  
{ TBU&6M>{3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); I`4*+a'q&  
break; q{;:SgZ  
} Nf1-!u7  
} k7usMVAA  
else QGmn#]w\\  
break; SS.dY""89  
} UFb )AnK  
} 0b(N^$js'  
catch(IOException e){e.printStackTrace ();} K:30_l<  
catch(Exception e){e.printStackTrace ();} OX\F~+  
I"7u2"@-8j  
bhlG,NTP  
Utility.log(nFileLength);  l"]}Ts#  
GYUn6P  
"o}+Ciul  
return nFileLength; @@ %.t|=  
} QWHug:c  
1 Nd2{(  
7g}w+p>  
//保存下载信息(文件指针位置) gQ1;],_  
private void write_nPos() 3HY9\'t6  
{ .];=Pu^  
try{ (n9g kO&8"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `~CQU  
output.writeInt(nStartPos.length); HJYScwjQ;`  
for(int i=0;i<nStartPos.length;i++) ]1pIj i[  
{ Z^MNf  
// output.writeLong(nPos); W#WVfr  
output.writeLong(fileSplitterFetch.nStartPos); .gOL1`b*  
output.writeLong(fileSplitterFetch.nEndPos); OMg<V  
} >_ 2dvg=U  
output.close(); L<{i ,'M  
} ThbGQ"/  
catch(IOException e){e.printStackTrace ();} zi*R`;_`,  
catch(Exception e){e.printStackTrace ();} naznayy  
} 2'MZ s]??w  
Ffta](Z;  
,>+p-M8ZL  
//读取保存的下载信息(文件指针位置) M,mvys$  
private void read_nPos() L"Olwwmk  
{ PxkO T*  
try{ GD_hhDyD  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2{G:=U  
int nCount = input.readInt(); b |p)9&^r  
nStartPos = new long[nCount]; |T)6yDL  
nEndPos = new long[nCount]; +l{=  
for(int i=0;i<nStartPos.length;i++) t "'7m^j  
{ i3'9>"`  
nStartPos = input.readLong(); T\ >a!  
nEndPos = input.readLong(); .O}%  
} dP]\Jo=Yh  
input.close(); D#JL!A%O  
} >{J(>B\  
catch(IOException e){e.printStackTrace ();} :mn>0jK,N  
catch(Exception e){e.printStackTrace ();} g:Xhw$x9  
} :\7X}n*&  
' AEE[  
56-dD5{hxR  
private void processErrorCode(int nErrorCode) xCl1g4N  
{ =uYYsC\T  
System.err.println("Error Code : " + nErrorCode); !Bq3Z?xA}  
} {w^+\]tC  
+8d1|cB"  
vbe|hO""  
//停止文件下载 6?~"V  
public void siteStop() #O} ,`[<  
{ 0-yp,G  
bStop = true; .j<]mUY  
for(int i=0;i<nStartPos.length;i++) TXvI4"&  
fileSplitterFetch.splitterStop(); "v({ ,  
~=RT*>G_  
KRMQtgahc  
} OCaq3_#tZ  
} @wo(tf=@P  
//负责部分文件的抓取 0+;bh {Eu  
**FileSplitterFetch.java 90*5 5\>{  
*/ Y U5(g^<  
package NetFox; J!pygn O  
8MzVOF{"  
)@Yf]qx+Y<  
import java.io.*; mtmjZP(w   
import java.net.*; .NC:;@y  
x&Kh>PVh\  
p &"`RS #Z  
public class FileSplitterFetch extends Thread { qUGC" <W  
};jN\x?&q  
(VEpVn3{  
String sURL; //File URL 5T2CISmu  
long nStartPos; //File Snippet Start Position ``\i58K{e  
long nEndPos; //File Snippet End Position *>2W#D)b=  
int nThreadID; //Thread's ID v)t:|Q{I  
boolean bDownOver = false; //Downing is over OJ5#4qJ[  
boolean bStop = false; //Stop identical <;m<8RjX  
FileAccessI fileAccessI = null; //File Access interface r@t9Ci=}  
Mh/dpb\Z  
*<jAiB ,O*  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Q1 $^v0-)  
{ {NFr]LGOp  
this.sURL = sURL; >\=3:gb:  
this.nStartPos = nStart; "wn zo,  
this.nEndPos = nEnd; h"_;IUZ!  
nThreadID = id; yt=3sq  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :LRYYw  
}  SVs_dG$  
6NM:DI\%  
i}mVQ\j5  
public void run() RcM/!,B  
{ ?Unb? {,&2  
while(nStartPos < nEndPos && !bStop) :f}9($  
{ ,<tX%n`v=  
T;y>>_,  
>dG;w6y'  
try{ =Og)q$AL  
URL url = new URL(sURL); %GA"GYL9'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); evAMJ=  
httpConnection.setRequestProperty("User-Agent","NetFox"); pU%n]]qF  
String sProperty = "bytes="+nStartPos+"-"; #W'HR  
httpConnection.setRequestProperty("RANGE",sProperty); wKY Za# u  
Utility.log(sProperty); y 4I6  
:'3XAntZA  
X=!^] 3zH  
InputStream input = httpConnection.getInputStream(); w?wG(+X7  
//logResponseHead(httpConnection); vss(twg  
: $Y9jR  
m)v"3ib  
byte[] b = new byte[1024]; Nj xoTLI  
int nRead; Ba*,-i3ZK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) m4&h>9. 8  
{ luuX2Mx>o  
nStartPos += fileAccessI.write(b,0,nRead); "2P&X  
//if(nThreadID == 1) WEQ1 Seq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +HeTtFo{M  
} /F-qP.<D,r  
Gh}LlX!w  
Y*>#T  
Utility.log("Thread " + nThreadID + " is over!"); =Ja]T~0A  
bDownOver = true; (\a]"g,]v  
//nPos = fileAccessI.write (b,0,nRead); 1+qw$T  
} t2"O  
catch(Exception e){e.printStackTrace ();} qnJt5  
} f3&[#%  
} iZNts%Y]  
D 38$`j  
Y/ >&0wj)d  
//打印回应的头信息 X4AyX.p  
public void logResponseHead(HttpURLConnection con) ZP *q4:  
{ sCis4gX.]  
for(int i=1;;i++) )5%'.P>  
{ 'EF9Zt8  
String header=con.getHeaderFieldKey(i); wEE\+3b)  
if(header!=null) *:t|qgJI#+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *-q"3 D`  
Utility.log(header+" : "+con.getHeaderField(header)); Nq` C.&  
else P8>d6;o($  
break; xA 1hfe.9  
} v:o({Y 1Aq  
} KgOqbSJ  
Mjfx~I27  
~Ro9u p  
public void splitterStop() s3O} 6  
{ Q`D~5ci  
bStop = true; YW`,v6  
} (TwnkXrR,  
, GY h9  
3k# /{Z  
} }YMy6eW4  
t!x5fNo)  
y[\VUzD*'  
/* m&\h4$[kql  
**FileAccess.java 2f:Eof(B  
*//文件访问(定位,写) }i`PGx  
package NetFox; {Jx4xpvPo  
import java.io.*; ]dk8lZ;bo  
("+}=*?OF3  
X4t s)>"d  
public class FileAccessI implements Serializable{ ;A'Z4=*~  
K]|> Et`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 bKQ"ax>6p  
RandomAccessFile oSavedFile; rN<b?KE  
long nPos; H nUYqhZS  
Eu-RNrYh#  
s#DaKPC  
public FileAccessI() throws IOException L19C<5>  
{ ^Au _U  
this("",0); [y)`k@  
} 1Q4}'0U4  
$Y_i4(  
)h|gwERj  
public FileAccessI(String sName,long nPos) throws IOException &S]@Ot<z  
{ F;[T#N:~  
oSavedFile = new RandomAccessFile(sName,"rw"); 7.@TK&  
this.nPos = nPos; %]6~Eq%s  
oSavedFile.seek(nPos); @@rEs40  
} m-DsY  
P=&o%K,:f  
<Ib[82PU  
public synchronized int write(byte[] b,int nStart,int nLen) vab@-=%k  
{ tBT<EV{ G  
int n = -1; AfP 'EP0m  
try{ 9D}/\jM  
oSavedFile.write(b,nStart,nLen); ,FMx5$  
n = nLen; ivz>dJ?T  
} :ORR_f`>  
catch(IOException e) }kK[S|XVO  
{ ]oV{t<0a  
e.printStackTrace (); P=+nB*hG  
} )aao[_ZS  
VX+jadYdq  
MJCzo |w  
return n; Qb; d:@9  
} M=*bh5t%]  
xIGfM>uq  
''^Y>k  
} /`;n@0k>2  
rs*Fy@  
K ryo}  
/* d]i(h~?_  
**SiteInfoBean.java RUUk f({(  
*/ !>`N$-U X  
package NetFox; <ggtjw S  
!!V#v9{  
+:-57  
public class SiteInfoBean { ^1x*lLf  
npyAJp  
M- 2Tz[  
private String sSiteURL; //Site's URL ls`,EFF  
private String sFilePath; //Saved File's Path +|{RE.DL  
private String sFileName; //Saved File's Name f%)zg(YlO  
private int nSplitter; //Count of Splited Downloading File $GQ-(/  
KdUnD4d  
za9)Q=6FD  
public SiteInfoBean() )VK }m9Ae  
{//nSplitter的缺省值为5 Za7q$7F7Bc  
//default value of nSplitter is 5 7`H 1f]d  
this("","","",5); 6^n0[7  
} j:&4-K};Z`  
'K*AV7>E  
OxtOd\0$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) l|+BC  
{ |U k" {  
sSiteURL= sURL; q;D+ai  
sFilePath = sPath; xc:!cA{V  
sFileName = sName; 8?O>ZZtu  
this.nSplitter = nSpiltter; P;8>5;U4-  
Enq|Y$qm  
T<joR R  
} J5[~LZKW  
r-IVb&uF b  
deeU@x`f<  
public String getSSiteURL() q$.{j"cZV  
{ dg7=X{=9jv  
return sSiteURL; V~yAE @9  
} %tt%`0  
J3b4cxm  
@[?!s%*2  
public void setSSiteURL(String value) d ~_`M0+  
{ u@P[Vb   
sSiteURL = value; >A q870n  
} EIbXmkHl<  
BtdXv4V  
sz):oea@f@  
public String getSFilePath() 7"*|2Xq  
{ \mN[gT}LHm  
return sFilePath; y3;q_4.  
} 5Wj; [2 )  
%T=A{<[`  
zT* .jv  
public void setSFilePath(String value) \#x}q'BC4  
{ V*$L;xbC|  
sFilePath = value; !b-bP,q  
} Na,_  
` C+HE$B  
ixh47M  
public String getSFileName() O0*e)i8  
{ ZRUhAp'<qj  
return sFileName; ?Jusl8Sm  
} wVA|!>v  
XfzVcap  
PaCzr5!~f  
public void setSFileName(String value) jSQ9.%4  
{ >(tn"2  
sFileName = value; B)h>8 {  
} X0+fsf<H}  
7W9d6i)  
0i8h I6d  
public int getNSplitter() oXt,e   
{ hsG#6?l3  
return nSplitter; rt+..t\  
} do>"[RO  
?68uS;  
|__=d+M'  
public void setNSplitter(int nCount) QldzQ%4c\  
{ =]Hs|{  
nSplitter = nCount; z&$/EP-  
} D 0]a\,aZ  
} g#K'6VK{  
y466A]|  
i(wgB\9i4  
/* dow^*{fqZ  
**Utility.java } i)$n(A)K  
*/ qturd7  
package NetFox; Y ZaP  
7/X"z=Q^|  
Zq ot{s  
public class Utility { N\1/JW+  
I]J*BD#n.  
/=#~  
public Utility() ;+I4&VieK  
{ TQ1WVq }*  
Lg`Jp&Kg  
, Ut Hc]  
} [ij,RE7,T  
g>7Y~_}  
//线程睡眠 {lzG*4?  
public static void sleep(int nSecond) [~k]{[NJ  
{ >n7["7HHk  
try{ z]$j7dp  
Thread.sleep(nSecond); vh>{_ #  
} DcV<y-`'1  
catch(Exception e) azb=(l-  
{ oBlzHBn>0  
e.printStackTrace (); 8!h'j  
} ._p""'Sa  
} 5>ST"l_ca  
O'}l lo  
//日志  ?9u4a_x  
public static void log(String sMsg) {%']w  
{ d\XRUO[  
System.err.println(sMsg); i&@,5/'-_O  
} ^ZQCIS-R  
LE c8NQs  
DQ=N1pft2v  
public static void log(int sMsg) A@$fb}CF  
{ iIU( C.I  
System.err.println(sMsg); Gbd?%{Xc-  
} 3BMS_,P  
} R~B0+:6  
udTxNl!  
6|;0ax4:P  
/* n2;9geq+  
**TestMethod.java 6;uBZ &g  
*/ 5FuK\y  
package NetFox; ?'~;Q)  
1]/N2&  
,p,Du F  
public class TestMethod { U=o Z.\  
a0zG(7.D  
NR/-m7#-  
public TestMethod() |Odu4 Q  
{ ///xx/weblogic60b2_win.exe .Y/-8H-3v  
try{ l6B.6 '4)w  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4IGxI7~27#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); T=? bdIl  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .{N\<01  
fileFetch.start(); )Ul&1UYA  
} ye r> x  
catch(Exception e){e.printStackTrace ();} .g-3e"@  
{u]CHN`%Z  
TSyzdnMvz  
} o#d$[oa  
8)Tj H'  
1e$[p[  
public static void main(String[] args) L+Nsi~YVq  
{ qU6BA \ZL  
new TestMethod(); 712=rUI%!  
} 1XnBK$`  
} nJ# XVlHc  
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