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http断点续传简单实现(java)

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/* . *9+%FN  
**SiteFileFetch.java R`7v3{  
*/ ^>?E1J3u  
package NetFox; s|/m}n  
import java.io.*; sk0N=5SB-  
import java.net.*; a{?`yO/ 2  
mY}_9rTn|  
+Xb )bfN  
public class SiteFileFetch extends Thread { vrS)VJg`  
AixQR[Ul*c  
95`Q=I|i  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3 #fOrNU2  
long[] nStartPos; //开始位置 ]Bp db'  
long[] nEndPos; //结束位置 QQQ3U  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 I|RMxx y;  
long nFileLength; //文件长度 XxN=vL&m  
boolean bFirst = true; //是否第一次取文件 Y} '8`.  
boolean bStop = false; //停止标志 ?A!Lh,  
File tmpFile; //文件下载的临时信息 5kX#qT=  
DataOutputStream output; //输出到文件的输出流 ;g-L2(T05;  
m\3r<*q6  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Bl)znJ^  
public SiteFileFetch(SiteInfoBean bean) throws IOException cBgdBPDa  
{ zjyj,jP  
siteInfoBean = bean; 8{mQmG4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h)O<bI8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); WYHr'xJ  
if(tmpFile.exists ()) Iyo ey  
{ @B<B#  
bFirst = false; t>04nN_@,s  
read_nPos(); eSV_.uvsb  
} [1I>Bc&o*  
else (r&e|  
{ I'23$IzPA  
nStartPos = new long[bean.getNSplitter()]; R @h@@lSf  
nEndPos = new long[bean.getNSplitter()]; x~7_`=}rO  
} IEi E6z]L(  
=cy;{2S'p  
(thDv rT@2  
?DAW~+,!7o  
} P'4oI0Bw  
jU4*fzsZI  
o6@Hj+,,  
public void run() kR C0iTV'I  
{ n+5X*~D  
//获得文件长度 :z;}:+7n  
//分割文件 k\:f2%!!  
//实例FileSplitterFetch 8,E#vQ55}(  
//启动FileSplitterFetch线程 |]qwD,eiH,  
//等待子线程返回 1[QH68  
try{ $VX<UK$|s  
if(bFirst) P #_8$#G3  
{ B3p[A k  
nFileLength = getFileSize(); j Hd <*  
if(nFileLength == -1) %h "+J  
{ ^7l.!s#$b  
System.err.println("File Length is not known!"); [+=h[DC  
} V;b^b5yZ>  
else if(nFileLength == -2) _g%Wx?K9  
{ T>"GH M  
System.err.println("File is not access!"); m?Gb5=qo  
} A+JM* eB  
else p[Z'Fl  
{ QlbhQkn  
for(int i=0;i<nStartPos.length;i++) DYvi1X6  
{ 8"C;I=]8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J- %YmUc)  
} GJ>vL  
for(int i=0;i<nEndPos.length-1;i++) .x$!Rc}  
{ X%+FM]  
nEndPos = nStartPos[i+1]; $,vZX u|Qw  
} -0KQR{LI  
nEndPos[nEndPos.length-1] = nFileLength; $ Cr? }'a  
} )~hsd+ 0t  
} #}^ kMD >  
Y(>]7  
{.W$<y (j7  
//启动子线程 G\ twx ;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; V24i8Qx  
for(int i=0;i<nStartPos.length;i++) |"[[.Adw9"  
{ |51z&dG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )^&,[Q=i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), M2[ywab  
nStartPos,nEndPos,i); ~I0I#_$'P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B_u+$Odo  
fileSplitterFetch.start(); &Wj %`T{  
} b"Hg4i)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NN<kO#c+2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); t7VXW{3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", N=) E$h  
nEndPos = " + nFileLength); LK8K=AA3P  
// fileSplitterFetch[nPos.length-1].start(); 3r=IO#  
WMB~? EDhv  
JwzA'[tM  
//等待子线程结束 w%,Iy, G@  
//int count = 0; tS2P|fl  
//是否结束while循环 ]xf lfZ  
boolean breakWhile = false; 7y",%WYSD  
Qtmsk:qm  
MSPzOJQPy  
while(!bStop) K5x&:z  
{ >w:px$g4  
write_nPos(); ziuhS4k  
Utility.sleep(500); H'uRgBjWJ  
breakWhile = true; 0T!_;IQ  
u7!X#<  
axOdGv5  
for(int i=0;i<nStartPos.length;i++) e_6@oh2s-  
{ V Iof4?i  
if(!fileSplitterFetch.bDownOver) C\7qAR\  
{ cdL$T6y  
breakWhile = false; EP#3+B sH  
break; mw<LNnT{8  
} 5S'89 r3m  
} XUU l*5^  
if(breakWhile) 89F^I"Im(  
break; dMsX}=EI<  
'?+q3lps  
Aa* UV6(v  
//count++; M*)}F  
//if(count>4) B7qm;(?X&  
// siteStop(); wi]|"\  
} |H&2[B"l  
g/+P]c6/  
o.5w>l!9K  
System.err.println("文件下载结束!"); q#Y%Y  
} 6 2&E]>A(i  
catch(Exception e){e.printStackTrace ();} 4/S% eZB  
} gIS<"smOo  
}q-_|(b;  
 WpX)[au  
//获得文件长度 tP2hU[7Z  
public long getFileSize() >Pv#)qtm  
{ ]|[,N>  
int nFileLength = -1; rlYAy5&  
try{ Q4 Mp[  
URL url = new URL(siteInfoBean.getSSiteURL()); C=}YKsi|R|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l]whL1N3  
httpConnection.setRequestProperty("User-Agent","NetFox"); kUAjQ>  
]zHUF!a*  
vMJv.O>HW  
int responseCode=httpConnection.getResponseCode(); ^JF6L`Tp  
if(responseCode>=400) p=6Q0r|'  
{ bit&H  
processErrorCode(responseCode); //VgPl  
return -2; //-2 represent access is error +*[lp@zU{  
} lmb5Z-xB  
qp>O#tj[  
|yiM7U,i  
String sHeader; t&(}`W  
j+Nun  
d^X;XVAvP  
for(int i=1;;i++) <5MnF  
{ 2.O;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~4o2!!^tI  
//Utility.log(in.readLine()); <Yfk7Un  
sHeader=httpConnection.getHeaderFieldKey(i); XA} !  
if(sHeader!=null) ']1j M n  
{ {20^abUAS  
if(sHeader.equals("Content-Length")) gQf'|%)AJ  
{ q#Az\B:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); KumbG>O  
break; uWR\#D'  
} zzi%r=%r&  
} bLoAtI  
else Ia:n<sZU  
break; $x]'6  
} [;II2[5 ,  
} ]V J$;v'{[  
catch(IOException e){e.printStackTrace ();} <R>qOX8  
catch(Exception e){e.printStackTrace ();} 9RwD_`D(MN  
%..{c#V  
H27_T]\  
Utility.log(nFileLength); TI:-Y@8  
A:F*Y%ZW  
\?&P|7N  
return nFileLength; 6sBS;+C  
} LhC%`w  
m\|I.BUG  
MGeHccqh2  
//保存下载信息(文件指针位置) a6"Pe07t  
private void write_nPos() |Vc8W0~0  
{ L%9DaK  
try{ kL,bM.;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |XOD~Plo^  
output.writeInt(nStartPos.length); cP63q|[[  
for(int i=0;i<nStartPos.length;i++) NK]X="`  
{ aH'Sz'|E  
// output.writeLong(nPos); E[HXbj"  
output.writeLong(fileSplitterFetch.nStartPos); :9q=o|T6D  
output.writeLong(fileSplitterFetch.nEndPos); #4_'%~-e  
} zb Z0BD7e  
output.close(); =@;uDu:Q  
} ]N}80*Rl  
catch(IOException e){e.printStackTrace ();} c.m8~@O5+  
catch(Exception e){e.printStackTrace ();} j`Fsr?]/  
} />_Mz  
D Cx3_  
B25@6   
//读取保存的下载信息(文件指针位置) vtG_ A{l  
private void read_nPos() 61>@-55k9  
{ oe,L&2Jz@  
try{ 3{ i'8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +[Nc";Oy  
int nCount = input.readInt(); qT^R> p  
nStartPos = new long[nCount]; -m)N~>{qS  
nEndPos = new long[nCount]; AB40WCu]*  
for(int i=0;i<nStartPos.length;i++) 5an#,vCn{  
{ L31B:t^  
nStartPos = input.readLong(); :%Na-j9hV)  
nEndPos = input.readLong(); Xu $_%+46  
} @x?7J@:  
input.close(); #rM/  
} ST1PSuC~  
catch(IOException e){e.printStackTrace ();} _x_om#~n  
catch(Exception e){e.printStackTrace ();} W&dYH 4O  
} c*$&MCh  
6f/>o$  
Q-fi(UP  
private void processErrorCode(int nErrorCode) 8nw_Jatk1  
{ V6Ie\+@.\  
System.err.println("Error Code : " + nErrorCode); U`sybtuBP'  
} hK*:pf  
z8FeL5.(  
1\t}pGSOeh  
//停止文件下载 KW|X\1H  
public void siteStop() )3PQ|r'  
{ ?it49  
bStop = true; 4^(u6tX5|+  
for(int i=0;i<nStartPos.length;i++) nBv|5$w:  
fileSplitterFetch.splitterStop(); F-g(Hk|v  
833KU_ N  
l/0TNOA  
} 9{_D"h}}  
} !fUrDOM0E  
//负责部分文件的抓取 syhTOhOX  
**FileSplitterFetch.java UO$z_ p]w  
*/ nAv@^G2  
package NetFox; 52K_kB5  
+[M5x[[$  
;|&Ak_I2G  
import java.io.*; _!6~o>  
import java.net.*; OnFx8r:q@%  
V}(snG,  
pH5"g"e1  
public class FileSplitterFetch extends Thread { vk:@rOpl  
nf?;h!_7  
Cp(,+ dD  
String sURL; //File URL >:%YAR`  
long nStartPos; //File Snippet Start Position o\u31,  
long nEndPos; //File Snippet End Position 1"ko wp  
int nThreadID; //Thread's ID \hv1"WaJ  
boolean bDownOver = false; //Downing is over 1c_qNI;:p  
boolean bStop = false; //Stop identical J&4LyIpQ  
FileAccessI fileAccessI = null; //File Access interface +ew2+2  
S*~v9+  
,!U 5;  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]^:l?F\h  
{ Vvu+gP'z.  
this.sURL = sURL; A7SBm`XJ)p  
this.nStartPos = nStart; 1V(tt{  
this.nEndPos = nEnd; i3g;B?54  
nThreadID = id; 9NLO{kN  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 M6U/. n  
} os*QWSs  
|9. `qv  
"J^M@k\!  
public void run() 3Qmok@4e)  
{ ^,[V;3  
while(nStartPos < nEndPos && !bStop) `r;e\Cp  
{ U WYLT-^x  
Q|Uq.UjY  
Q| > \{M  
try{ Wo=Q7~  
URL url = new URL(sURL); =+`I%>wc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {<%zcNKl^L  
httpConnection.setRequestProperty("User-Agent","NetFox");  4KF 1vw  
String sProperty = "bytes="+nStartPos+"-"; 1HK5OT&  
httpConnection.setRequestProperty("RANGE",sProperty); ~_=ohb{  
Utility.log(sProperty); O{hGh{y  
"P;_-i9O  
4Sv&iQ=vh  
InputStream input = httpConnection.getInputStream(); ,p6X3zY  
//logResponseHead(httpConnection); [X[d`@rXv  
 L>Bf}^  
r2H_)Oi  
byte[] b = new byte[1024]; qg?O+-+  
int nRead; Fn0Rq9/@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /Y|oDfv  
{ tkU"/$Vi\  
nStartPos += fileAccessI.write(b,0,nRead); vy\;#X!  
//if(nThreadID == 1) -ZqN~5>j)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *fVs|  
} A8Q1x/d(  
J2H/z5YRJ4  
)P>Cxzs  
Utility.log("Thread " + nThreadID + " is over!"); h7mJXS)t|  
bDownOver = true; bAv>?Xqa  
//nPos = fileAccessI.write (b,0,nRead); /pzEL  
} Gr6XqO_  
catch(Exception e){e.printStackTrace ();} E ?(+v  
} KA1Z{7UK%  
} =\H.C@r  
_uU}J5d.  
~3 4Ly  
//打印回应的头信息 ]5b%r;_  
public void logResponseHead(HttpURLConnection con) O@St^o*A}  
{ )u~LzE]{_  
for(int i=1;;i++) %9hzz5#  
{ =BW>jD  
String header=con.getHeaderFieldKey(i); l(|@ dp  
if(header!=null) [H$37Hx !  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); OpeK-K  
Utility.log(header+" : "+con.getHeaderField(header)); _ Js & _d  
else FaO=<jYi  
break; HVG9 C$  
} 2@WF]*Z  
} `h+ia/  
wlr/zquAE9  
IKSe X  
public void splitterStop() e -vL!&;2  
{ H/m -$;cF3  
bStop = true; CbTYt6DC  
} 6u^M fOc  
$r})j~c  
M;*f(JY$  
} {2?o:  
qv|geBW  
%|md0  
/* 3uA%1 E  
**FileAccess.java .zf#S0y%(  
*//文件访问(定位,写) aV3:wp]Gn  
package NetFox; `PK1zSr  
import java.io.*; T^YdAQeE  
iW\cLp "  
'&4W@lvyz  
public class FileAccessI implements Serializable{ KO/Z|I  
I_xvg >i  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4A(kM}uRB  
RandomAccessFile oSavedFile; 1+6)0 OH{  
long nPos; 3}{od$3G  
Yg@k +  
"e<Z$"7i  
public FileAccessI() throws IOException J*s!(J |Q  
{ V;$ME4B\{  
this("",0); MzLnD D^  
} W ]cJP  
_ S%3?Q  
`?)ivy>\:  
public FileAccessI(String sName,long nPos) throws IOException kd^CZ;O  
{ IfF@$eO  
oSavedFile = new RandomAccessFile(sName,"rw"); *|S.[i_7  
this.nPos = nPos; ^6Y4=  
oSavedFile.seek(nPos); $w{!}U2+-  
} x#z}A&  
%7WQb]y  
}nNZp  
public synchronized int write(byte[] b,int nStart,int nLen) Kp[ F@A#  
{ Ul#||B .c{  
int n = -1; @C7if lo6  
try{ ht _fbh(l  
oSavedFile.write(b,nStart,nLen); P)bS ;w\(Y  
n = nLen; f4Aevh:  
} uN1(l}z$  
catch(IOException e) 1I< <`7'  
{ 3_k.`s_Z  
e.printStackTrace (); 2L}F=$zz  
}  ;ew j  
<:=}1t.Z  
B;f\H,/59  
return n; U_!Wg|  
} QRb iO  
PYWp2V/  
X1Vx 6+[  
} \%Wu`SlDp9  
[_W#8{  
p^1s9CM%  
/* /.!ytHw8  
**SiteInfoBean.java o'nju.'  
*/ _ZUtQ49  
package NetFox; Y] Q=kI  
+dd\_\  
{.=4;   
public class SiteInfoBean { !Cse,6/Z  
UzZzt$Kw  
VB x,q3.  
private String sSiteURL; //Site's URL ]7SX _:'*  
private String sFilePath; //Saved File's Path HPM ggRs  
private String sFileName; //Saved File's Name (80 Tbi~+  
private int nSplitter; //Count of Splited Downloading File ;Y<Hi\2oy  
^id9_RU   
YCJcDab  
public SiteInfoBean() {s^vAD<~x3  
{//nSplitter的缺省值为5 s~OGl PK  
//default value of nSplitter is 5 uA]Z"  
this("","","",5); w@ 1g_dy  
} Jo%5NXts4  
""-#b^DQ  
@2H"8KX  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $Pw@EC]  
{ t As@0`x9  
sSiteURL= sURL; J,@SSmJ`  
sFilePath = sPath; %mLQ'$  
sFileName = sName; bvVEV  
this.nSplitter = nSpiltter; dg#w/}}m  
3/+r*lv>X  
lP$bxUNt  
} JBY`Y ]V3  
\Km gFyF  
tuZA q;X  
public String getSSiteURL() }O=QXIF5  
{ u#TRm?s  
return sSiteURL; v/dyu  
} frB~ajXK  
v2X>%  
Nr24Rv  
public void setSSiteURL(String value) ""LCyKu   
{ u~kfz*hz  
sSiteURL = value; (sX=#<B%  
} & w%%{lM  
RY8Ot2DWi  
#Av6BGM|,  
public String getSFilePath() QuEfV?)_4  
{ CUz1 q*):  
return sFilePath; Snm m (.  
} R.KqTEs<k  
<zmtVE*>g  
0#K?SuY.eN  
public void setSFilePath(String value) ;%u'w;sgq  
{ +C`h*%BW  
sFilePath = value; y_aKW4L+  
} gWlv;oq  
NI(fJ%U  
'FVh/};Y.D  
public String getSFileName() ^.']-XjC  
{ :Bk!YK  
return sFileName; v.eNWp  
} G-5wv  
%Pl 7FHfB  
h!c6]D4!L  
public void setSFileName(String value) w.tQ)x1h  
{ Q<TD5t9  
sFileName = value; 6O|B'?]Pf  
} TRB)cJZ?  
vkFfHzR$  
EVovx7dr  
public int getNSplitter() :`FL95  
{ iF.eBL%  
return nSplitter; /]0-|Kg+R  
} )HLe8:PG~  
?`& l Y  
M]\p9p(_  
public void setNSplitter(int nCount) >FrF"u:kM  
{ P F#X8+&J  
nSplitter = nCount; (``EBEn  
} =P* YwLb  
} \FVm_)  
o;.6Y `-fJ  
x6=Yt{  
/* ;QMRm<CLV  
**Utility.java Gp}:U>V)  
*/ #;4afj:2g  
package NetFox; Z0fl]3p  
q]1HCWde  
1h.Ypz u  
public class Utility { wI\ n%#  
YX||\  
n veHLHvC7  
public Utility() .=y-T=}  
{ e1*<9&S  
o6{[7jI  
Mi|PhDXMh  
} >]6 inS9  
;.%Ii w&WG  
//线程睡眠  bnll-G|  
public static void sleep(int nSecond) z|';Y!kQ  
{ `5VEGSP]  
try{ ~d+.w%Z `  
Thread.sleep(nSecond); < 5%:/j  
} 43i@5F]  
catch(Exception e) g>])O  
{ Vl91I+Ev  
e.printStackTrace (); iy{n"#uX  
} xG802?2i/;  
} "rV-D1Dki  
YMlnC7?_ /  
//日志 f:/[  
public static void log(String sMsg) q7itznQSKc  
{ sbWen?  
System.err.println(sMsg); BvXA9YQ3  
} D1Yc_  
y)`f$Hl@1  
NGA8JV/U  
public static void log(int sMsg) O26'|w@$  
{ ]_8bX}_n  
System.err.println(sMsg); u`%Kh_  
} (A\X+S(  
} 2WKYf0t  
0+a-l[!p  
;<aT| 4  
/* Zd2B4~V  
**TestMethod.java Mqy5>f)  
*/ |sQC:y>  
package NetFox; \S]"nHX  
$:{r#mM  
o\n9(ao  
public class TestMethod { ;S+UD~i[Bu  
O8&=qZ6T  
@P1#)  
public TestMethod() 4#pn ]  
{ ///xx/weblogic60b2_win.exe wi7a_^{  
try{ 3^ct;gz  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %kod31X3<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zv1#PfO@)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5PaOa8=2f  
fileFetch.start(); h .A@o#x  
} KW3Dr`A  
catch(Exception e){e.printStackTrace ();} )<]*!  
4|?y [j6  
~ULD{Ov'F  
} 9VEx0mkdd  
'p%\fb6`  
7Wd}H Z  
public static void main(String[] args) k0%*{IVPN  
{ 0|1)cO}Dy  
new TestMethod(); ~OuKewr\  
} i,[S1g  
} 0^5*@vt  
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