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http断点续传简单实现(java)

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/* zF&_9VNk=c  
**SiteFileFetch.java YW"nPZNPy~  
*/ p&HkR^.S  
package NetFox; }mS+%w"j  
import java.io.*; KCn#*[  
import java.net.*; +@<@x4yt  
]K<7A!+@@p  
IOl0=+p  
public class SiteFileFetch extends Thread { f1t?<=3Ek<  
!KHbsOT?9  
3GZrVhU?m  
SiteInfoBean siteInfoBean = null; //文件信息Bean M ED_#OS  
long[] nStartPos; //开始位置 a(x#6  
long[] nEndPos; //结束位置 T=fVD8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Vtk}>I@%  
long nFileLength; //文件长度 bW zUWLa  
boolean bFirst = true; //是否第一次取文件 ^k!u  
boolean bStop = false; //停止标志 Hlj3z3  
File tmpFile; //文件下载的临时信息 M2nZ,I=l  
DataOutputStream output; //输出到文件的输出流 ; $UB@)7%  
,k m`-6.2?  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) M\kct7Y  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~%sNPKjA  
{ ] .c$(.  
siteInfoBean = bean; qwo{34  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^0 /!:*?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); kqLpt  
if(tmpFile.exists ()) [O6JVXO>  
{ "mcuF]7F  
bFirst = false; ZMch2 U8  
read_nPos(); I5g!c|#y  
} ?<soX8_1  
else i.+#a2   
{ >  !WFY  
nStartPos = new long[bean.getNSplitter()]; 3 FLht L  
nEndPos = new long[bean.getNSplitter()]; 2O`s'&.h  
} > Cx;h=  
|l,0bkY@&  
wr2F]1bh@  
5I5#LQv0  
} I@q4D1g  
ae] hCWK  
J(`(PYo\i  
public void run() aMyf|l.  
{ =7zvp,B  
//获得文件长度 5R O_)G<  
//分割文件 ]$A6krfh|  
//实例FileSplitterFetch E D_J8 +  
//启动FileSplitterFetch线程 )eBCO~HS  
//等待子线程返回 Yk5Cyq  
try{ " R-Pe\W  
if(bFirst) 2}.EFQp+  
{ ~Yl%{1  
nFileLength = getFileSize(); RaB%N$.9s  
if(nFileLength == -1) n^rzl6dy  
{ $p.0[A(N  
System.err.println("File Length is not known!"); L%4Do*V&  
} y?V#LW[^E  
else if(nFileLength == -2) RZI4N4o  
{ (M,*R v  
System.err.println("File is not access!"); .p\<niu7  
} C-VkXk  
else }_cX" s  
{ .T7S1C $HP  
for(int i=0;i<nStartPos.length;i++) wTVd){q`.  
{ -[>G@m:?e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); FdmoR;  
} Vxim$'x!  
for(int i=0;i<nEndPos.length-1;i++) M"z3F!-j  
{ NSQf@o  
nEndPos = nStartPos[i+1]; Su[f"2oR  
} U9yR~pw  
nEndPos[nEndPos.length-1] = nFileLength; x5!lnN,#  
} J ?H| "  
} zvh&o*\2<d  
$lAhKpdlW  
(\$=+' hy  
//启动子线程 F0+@FS0   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bOdyrynh  
for(int i=0;i<nStartPos.length;i++) %hb!1I  
{ /PtmJ2 [  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <,(Ww   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), yyu f  
nStartPos,nEndPos,i); 8,&QY%8pX  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z~ {[YsG  
fileSplitterFetch.start(); R>`TV(W`9  
} r!O4]j_3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;O * o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); GZNfx8zsY+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Dq~D4|  
nEndPos = " + nFileLength); aZYs?b>Gm  
// fileSplitterFetch[nPos.length-1].start(); "pkn  
~(d#T|ez  
>[TJ-%V>oR  
//等待子线程结束 6R%N jEW:  
//int count = 0; ~b SjZ1`  
//是否结束while循环 <}^l MBa  
boolean breakWhile = false; G:?l;+P1  
V?+Y[Q  
Z)H9D(Za  
while(!bStop) Mj-B;r  
{  tvvRHvL  
write_nPos(); t[?O*>  
Utility.sleep(500); u7ER  
breakWhile = true; *6 1G<I  
agxR V  
)l*6zn`z  
for(int i=0;i<nStartPos.length;i++) YNWAef4  
{ BJ7m3[lz  
if(!fileSplitterFetch.bDownOver) / ,#&Htk  
{ }e0)=*;l  
breakWhile = false; Z\P&i#  
break; 9x[|75}l  
} <bxp/#6D  
} tD !$!\`O  
if(breakWhile) MbeO(Q  
break; $Xr9<)?,  
]{'lV~fc  
E7UYJ)6]  
//count++; Qg4g(0E@  
//if(count>4) @+ U++  
// siteStop(); yW)X asn  
} Sej\Gt  
)nJh) {4\  
Fl&Z}&5p  
System.err.println("文件下载结束!"); k->cqtG  
} !^<%RT9@|  
catch(Exception e){e.printStackTrace ();} } X[wWH  
} h$eVhN &Vv  
ia}V8i  
|qTS{qQh{L  
//获得文件长度 8q#Be1u<s2  
public long getFileSize() - Ado-'aaS  
{ 8st~ O  
int nFileLength = -1; ~g[<A?0=y  
try{ a)GT\1q  
URL url = new URL(siteInfoBean.getSSiteURL()); .~Z@y#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M]$_>&"  
httpConnection.setRequestProperty("User-Agent","NetFox"); `jyBF  
pJ 7="n  
7*&$-Hv  
int responseCode=httpConnection.getResponseCode(); #GT4/Ej}W  
if(responseCode>=400) Jv9yy~  
{ W6[# q%o  
processErrorCode(responseCode); EzDQoN7Em  
return -2; //-2 represent access is error V[N4 {c  
} V}UYr Va#9  
!K$qh{n  
JHZ`LWq  
String sHeader; K<Qy1y~[  
>*aqYNft  
9F^rXY.  
for(int i=1;;i++) UjI -<|  
{ oDEvhN T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); SYsbe 5j  
//Utility.log(in.readLine()); !Cv:,q  
sHeader=httpConnection.getHeaderFieldKey(i); I>L@ P`d  
if(sHeader!=null) Lw!Q*3c  
{ 7 -Yn8Gq  
if(sHeader.equals("Content-Length")) f.&((z?rC  
{ Pwh0Se5Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9:tn! <^=I  
break; #fR~ 7 KR  
} XY1e eB-  
} (jY -MF3  
else ,:1_I`d>#X  
break; E)=X8y  
} bAa+MB#A  
} ^E3i]Oem  
catch(IOException e){e.printStackTrace ();} Y]R;>E5o|  
catch(Exception e){e.printStackTrace ();} 3l8k O  
z1u1%FwOfM  
n!K<g.tjW  
Utility.log(nFileLength); {v>orP?  
D7"RZF\)  
YzD6S*wb  
return nFileLength; oTqv$IzqP  
} )KPQ8y!d  
)D1=jD(  
x.OCE`  
//保存下载信息(文件指针位置) t$W~X~//  
private void write_nPos() R%Y#vUmBV{  
{ ;.<0lnV  
try{ $ }D9)&f;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yxt `  
output.writeInt(nStartPos.length); CkJ\v%JAW  
for(int i=0;i<nStartPos.length;i++) @3:oo /;  
{ _PR> <L_  
// output.writeLong(nPos); OAhCW*B  
output.writeLong(fileSplitterFetch.nStartPos); bq<DW/  
output.writeLong(fileSplitterFetch.nEndPos); >x$.mXX{  
} f*}H4H EO  
output.close(); jZ8#86/#{  
} ,`ZIW  
catch(IOException e){e.printStackTrace ();} +bbhm0f  
catch(Exception e){e.printStackTrace ();} i!jR>+  
} lrXi *u]  
.^%!X!r  
_Bh ^<D-  
//读取保存的下载信息(文件指针位置) CQ+WBTiC  
private void read_nPos() ZV; lr Vv  
{ (t\ F>A  
try{ n 7Bua  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3:;2Av2(X.  
int nCount = input.readInt(); 6fOh *  
nStartPos = new long[nCount]; )j[rm   
nEndPos = new long[nCount]; PafsO,i-  
for(int i=0;i<nStartPos.length;i++) !}gC0dJ  
{ rg^  
nStartPos = input.readLong(); B.-1wZl  
nEndPos = input.readLong(); i!!1^DMrw  
} ZKv^q%92  
input.close(); @+3@Z?!SZ  
} x3JX}yCX  
catch(IOException e){e.printStackTrace ();} y~cDWD <h  
catch(Exception e){e.printStackTrace ();} UaQR0,#0y  
} D6KYkN(,v  
Z,~EH  
O#e'.n!rI  
private void processErrorCode(int nErrorCode) n' \poB?  
{ +H7lkbW  
System.err.println("Error Code : " + nErrorCode); -|l^- Qf!  
} _Co*"hl>2  
q DQ$Zq[  
fa7I6 i  
//停止文件下载  Pa .D+  
public void siteStop() U*.Wx0QM  
{ c :S A#.  
bStop = true; 6R%Ra  
for(int i=0;i<nStartPos.length;i++) RJ ,a}w[9  
fileSplitterFetch.splitterStop(); jt?937{  
pXfg{2  
=K6aiP$Ft  
} [xF(t @p  
} qRXb 9c  
//负责部分文件的抓取 ]-Z="YPY  
**FileSplitterFetch.java |U*wMYC  
*/ !2)$lM1@J  
package NetFox; SjT8 eH #  
3d qj:4[f  
,k*g `OTW  
import java.io.*; l2))StEm  
import java.net.*; WUQlAsme  
YQyf:xJ  
mHqw,28}  
public class FileSplitterFetch extends Thread { PVGvjc  
^-, aB  
UN7>c0B  
String sURL; //File URL "r6DZi(^K  
long nStartPos; //File Snippet Start Position wI!>IV(5  
long nEndPos; //File Snippet End Position ?U~9d"2=  
int nThreadID; //Thread's ID ;(cq aB  
boolean bDownOver = false; //Downing is over #$&!)13  
boolean bStop = false; //Stop identical k_p4 f%9  
FileAccessI fileAccessI = null; //File Access interface xef@-%mcoy  
50 :gk*hy  
D<=:9  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nE!h&}(  
{ (nWi9(}J  
this.sURL = sURL; A.a UWh  
this.nStartPos = nStart; E2M|b  
this.nEndPos = nEnd; @Sxb}XI!f  
nThreadID = id; i%m]<yElm  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 kW"6Gc&HUN  
} ;++CMTza]  
iXp*G52  
d4Y8q1  
public void run() Q`nsL)J  
{ n>d@}hyv  
while(nStartPos < nEndPos && !bStop) 39jnoT  
{ FL}k0  
6I0G.N  
*Uvh;d{  
try{ H 1`}3}"  
URL url = new URL(sURL); otQulL)T/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;A ~efC^<  
httpConnection.setRequestProperty("User-Agent","NetFox"); Tw|cgB  
String sProperty = "bytes="+nStartPos+"-"; 3<ikMUq&  
httpConnection.setRequestProperty("RANGE",sProperty); 7B@[`>5?%L  
Utility.log(sProperty); 1'c  
(1`z16  
2!Ip!IQ:  
InputStream input = httpConnection.getInputStream(); ZJCD)?]=3  
//logResponseHead(httpConnection); ZP>KHiA  
>7yOu!l  
>syQDB  
byte[] b = new byte[1024]; HmWU;9Vn+  
int nRead; h,-8( S  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tDF=Iqu)a  
{ [42vO  
nStartPos += fileAccessI.write(b,0,nRead); P`JO6O:&  
//if(nThreadID == 1) kPt9(E]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yi7m!+D3  
} Z x9oj  
g3r4>SA  
~NYy@l   
Utility.log("Thread " + nThreadID + " is over!"); bo]xah|."j  
bDownOver = true; u)]]9G _8  
//nPos = fileAccessI.write (b,0,nRead); Z83A1`!.|  
} RcQo1  
catch(Exception e){e.printStackTrace ();} XU f]gQu3=  
} ^T):\x(  
} Y|eB;Dm1q  
/s91[n(d  
}pP<+U  
//打印回应的头信息 9G7lPK  
public void logResponseHead(HttpURLConnection con) +8tdAw  
{ 86[/NTD<-  
for(int i=1;;i++) ,2H@xji [  
{ :JBvCyj4PE  
String header=con.getHeaderFieldKey(i); Qqt<  
if(header!=null) %nU8 Ca  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9.F+)y@  
Utility.log(header+" : "+con.getHeaderField(header)); F$l]#G.@A  
else K!|%mI8gk  
break; "c[ D 0{\{  
} 9$-V/7@)  
} DOi\DJV!  
C_>dJYM  
$vlc@]~d`&  
public void splitterStop() xHs8']*\  
{ eGZ{%\PH<  
bStop = true; a@[y)xa$Z  
} C]22 [v4  
x.Sq2rw]V  
SDY!!.  
} R)s@2S  
{1H3VSYq  
Q fI =  
/* 8mM^wT  
**FileAccess.java 1BQB8i-,  
*//文件访问(定位,写) q&.SB`  
package NetFox; 9(.P2yO  
import java.io.*; < * )u\A  
\}O'?)(1  
39s%CcI`k  
public class FileAccessI implements Serializable{ (A.%q1h  
Gy*6I)l  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 hhu !'(j  
RandomAccessFile oSavedFile; Isa]5>  
long nPos; *ujn+0)[  
a?]Ow J  
_e/>CiN/  
public FileAccessI() throws IOException 0QE2e'}}-  
{ n@9*>D U  
this("",0); E 9=a+l9  
} ZqaCe>  
;x.xj/7  
sxq'uF(K  
public FileAccessI(String sName,long nPos) throws IOException $0[T=9q <+  
{ MjIp~?*  
oSavedFile = new RandomAccessFile(sName,"rw"); 9Ra_[1  
this.nPos = nPos; y99 3uP   
oSavedFile.seek(nPos); 16q"A$  
} ]=5nC)|  
,U_p6 TV5  
T\g%.  
public synchronized int write(byte[] b,int nStart,int nLen) RIXUzKLO  
{ Fs rGI (x?  
int n = -1; k@qn' Zi  
try{ L&td4`2y  
oSavedFile.write(b,nStart,nLen); ]|cL+|':y  
n = nLen; !(=bH"P  
} b[<Q_7~2  
catch(IOException e) U0}]3a0  
{ 4%#C _pE9  
e.printStackTrace (); :cv_G;?  
} C^]y iR-U  
5;=,BWU  
I2JE@?  
return n; ?(Dk{-:T'  
} RC5b'+E&#  
(;^VdiJ  
)M5:aSRz  
} kFPZ$8e  
9OYsI  
@}&o(q1M0  
/* >mzK96  
**SiteInfoBean.java a%2r]:?^?  
*/ K-V NU  
package NetFox; MH{$"^K  
D4?qw$"  
m09 Bds  
public class SiteInfoBean { {b4+ Yc  
m S[Vl6  
n,eO6X 4  
private String sSiteURL; //Site's URL q7-Eu4w  
private String sFilePath; //Saved File's Path yw'b^D/  
private String sFileName; //Saved File's Name !2oe;q2X[G  
private int nSplitter; //Count of Splited Downloading File !@E=\Sm8EV  
RH+3x7 l  
7o?6Pv%HJC  
public SiteInfoBean() ?YR/'Vq97  
{//nSplitter的缺省值为5 L5C4#X  
//default value of nSplitter is 5 \& 6  
this("","","",5); B6tp,Np5,  
} 3rX5haD\  
c!@g<<}[(  
)ymd#?wq  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) U#v??Sl  
{ [bH5UTA  
sSiteURL= sURL; %h;~@-$  
sFilePath = sPath; Bfw]#"N`  
sFileName = sName; M|e Qds  
this.nSplitter = nSpiltter; *RKYdwnb  
A-:58Qau+  
ZgCG'SU  
} $Oa} U3  
 k?|l;6  
;c"T#CH.  
public String getSSiteURL() eaQ)r?M  
{ Y2i:ZP  
return sSiteURL; o@[yF<  
} ;j]0GD,c$  
F$Q( 2:w  
WlnmW(uahW  
public void setSSiteURL(String value) 3P C'P2  
{ )+2GF0%  
sSiteURL = value; Y*iYr2?;  
} F3/aq+<P[  
$fSV8n;Y  
-Y'Qa/:7  
public String getSFilePath() mXnl-_  
{ +rS}f N$L.  
return sFilePath; lb3:#?  
} L{xCsJ3d  
}9[E+8L1  
\ 4y7!   
public void setSFilePath(String value) hR" j[  
{ p(/PG+  
sFilePath = value; F8S -H"  
} ]v7f9MC'\  
COJny/FT|  
?<c)r~9]  
public String getSFileName() ia !t~~f  
{ nff&~lwhZ  
return sFileName; F)KUup)gc  
} 9u";%5 4  
>h>X/a(=~  
#|76dU  
public void setSFileName(String value) xwG=&+66  
{ uxF88$=!t  
sFileName = value; /I|.^ Id|  
} q h;ahX~  
4PUSFZK?  
fMRBGcg7Dc  
public int getNSplitter() dD@k{5  
{ *Q=ER  
return nSplitter; U%3d_"{;  
} [80jG+6  
9dl\`zlA*  
iD=VNf  
public void setNSplitter(int nCount) v[VUX69  
{ 7)sEW#d!  
nSplitter = nCount; G v(bD6Rz  
} Gqvnc8V&  
} |FS,Av  
t?H.M  
kBYZNjSz  
/* UD6D![e  
**Utility.java '3B`4W,  
*/ F/z$jj)  
package NetFox; cRBdIDIc  
]O2ku^yM  
)3g7dtq}  
public class Utility { ZGrjb22M  
?r"][<  
sr%tEKba)  
public Utility() =)}m4,LA  
{ 'j>+eA>  
BH _y0[y  
>&V?1!N"  
} FT'_{e!M  
@cNBY7=  
//线程睡眠 Cw1Jl5OVZ  
public static void sleep(int nSecond) =/wAk0c^y  
{ i1RU5IRy|j  
try{ tX)l$oRPr  
Thread.sleep(nSecond); tpw0j CVu  
} iR j/Tm*T'  
catch(Exception e) a86m?)-c  
{ /rp.H'hC  
e.printStackTrace (); Gxk=]5<7  
} .U|e#t  
} V {R<R2h1  
g _fvbVX  
//日志 OU+oS,  
public static void log(String sMsg) _%#Q \ D  
{ WbZ{) i  
System.err.println(sMsg); -kY7~yS7  
} G!},jO*"  
WS6pm6@A*!  
z[:UPPbW  
public static void log(int sMsg) ;n?72&h  
{ W70J2  
System.err.println(sMsg); Ql8E9~h  
} Qp8. D4^@3  
} b Z c&uq_  
ZAe>MNtW  
r:.5O F}  
/* ='f<_FD  
**TestMethod.java <4s$$Uw}6%  
*/ m[&]#K6  
package NetFox; G4g <PFx  
m)4s4P57y  
.m_yx{FZ=  
public class TestMethod { 5Gm,lNQAv  
)yp+!\  
UEmNT9V  
public TestMethod() S%n5,vwE  
{ ///xx/weblogic60b2_win.exe (pXZ$R:  
try{  Isv@V.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); k]FP1\Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t6p}LNm(V  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pQr `$:ga  
fileFetch.start(); xi=Z<G  
} <-uE pF  
catch(Exception e){e.printStackTrace ();} v|acKux=t  
C$`z23E  
l{wHu(1  
} P1DYjm[+D  
^yDCX  
>QRpRHtb  
public static void main(String[] args) 5_";EED  
{  TA;  
new TestMethod(); 8m Tjf Br  
} `?VtB!p@x=  
} :Bc)1^ I  
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