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http断点续传简单实现(java)

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/* T,SCK^  
**SiteFileFetch.java "pW@[2Dkx/  
*/ q;#:nf"  
package NetFox; %;qDhAu0  
import java.io.*; f$p7L.d<  
import java.net.*; T$r?LIa ,Q  
)!jX$bK  
&p6^    
public class SiteFileFetch extends Thread { +U= !svE  
~zD*=h2C  
7R5!(g  
SiteInfoBean siteInfoBean = null; //文件信息Bean (043G[H'.  
long[] nStartPos; //开始位置 F,>-+~L=  
long[] nEndPos; //结束位置 tDwj~{a~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 A.@Af+  
long nFileLength; //文件长度 ' &j]~m  
boolean bFirst = true; //是否第一次取文件 >S=,ype~G  
boolean bStop = false; //停止标志 rtY4 B~_  
File tmpFile; //文件下载的临时信息 ]/y69ou  
DataOutputStream output; //输出到文件的输出流 :MbD=sX  
#uHl  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) |cd=7[B  
public SiteFileFetch(SiteInfoBean bean) throws IOException ug.'OR  
{ os~}5QJ  
siteInfoBean = bean; %x zgTZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); kFo&!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7<p? E7  
if(tmpFile.exists ()) 8bP4  
{ > g=u Y{Rf  
bFirst = false; 9a;8^?Ld%S  
read_nPos(); OJ2I (8P  
} bJ6@ B<  
else bhg OLh#  
{ ;_<K>r*  
nStartPos = new long[bean.getNSplitter()]; gP 6`q  
nEndPos = new long[bean.getNSplitter()]; #RWHk  
} rm nfyn  
k<cv80lhK  
aB+B1YdY"  
Z4aK   
} <rAk"R^  
jFThW N  
iz pFl@WS  
public void run() ]53'\TH  
{ ajMI7j^G  
//获得文件长度 g7),si*  
//分割文件 6K 6uB ~  
//实例FileSplitterFetch \~ql_X;3  
//启动FileSplitterFetch线程 4bZ +nQgLu  
//等待子线程返回 .e8S^lSl  
try{ xPJ kadu  
if(bFirst) P<GHX~nB  
{ |`i.8  
nFileLength = getFileSize(); :U$U:e  
if(nFileLength == -1) 6q]`??g.  
{ $bv l.c  
System.err.println("File Length is not known!"); I}{Xv#@o  
} p-1 \4  
else if(nFileLength == -2) #w:6<$  
{ [d~ 25  
System.err.println("File is not access!");  T24?1  
} J4;F k  
else #m<<]L(o8W  
{ (!9ybH;T  
for(int i=0;i<nStartPos.length;i++) &$ /}HND  
{ z`Cq,Sz/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1=X"|`<!  
} B{+ Ra  
for(int i=0;i<nEndPos.length-1;i++) 70&]nb6f  
{ ]\_T  
nEndPos = nStartPos[i+1]; en6oFPG   
}  L4,Ke  
nEndPos[nEndPos.length-1] = nFileLength; 5{uK;Vxse  
} ' y9yx[P  
} Md4JaFA(  
b!ea(D!:  
6bW:&IPQ;  
//启动子线程 r=3knCEWK  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @JL+xfz  
for(int i=0;i<nStartPos.length;i++) Q4JvFy0'  
{ J}vxK H#=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =P.m5e<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \dIQhF%%2  
nStartPos,nEndPos,i); r$Z_Kwe.|&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _^)<d$R<  
fileSplitterFetch.start(); H!NyM}jsr  
} / NlT[@T  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aj:B+}1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &@MiR8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", j7M[]/|  
nEndPos = " + nFileLength); &]?X"K  
// fileSplitterFetch[nPos.length-1].start(); G$"$k=[  
P95A _(T=[  
:W\xZ  
//等待子线程结束 @Ja8~5:  
//int count = 0; VY9|8g/  
//是否结束while循环 u< ,c  
boolean breakWhile = false; G`HL^/Z*  
IO\ >U(:vx  
W l+[{#  
while(!bStop) VYZkHjj)2i  
{ #+- /0{HT  
write_nPos(); Aey*n=V4#F  
Utility.sleep(500); Evn=3Tw  
breakWhile = true; AShnCL8uR  
a|x1aN 0  
{G D<s))  
for(int i=0;i<nStartPos.length;i++) 1*"t-+|  
{ DGwN*>X  
if(!fileSplitterFetch.bDownOver) u(s/4Lu  
{ :OVre*j  
breakWhile = false; =a<};X  
break; ! Bv"S0  
} WD^!G;}  
} '>]9efJA  
if(breakWhile) 8SGFzb! h  
break; WYb\vm =r  
RG)!v6  
@KhDQ0v]5  
//count++; (,gpR4O[  
//if(count>4) >*PZ&"}M  
// siteStop(); \+cU}  
} f(h nomn  
G Uf[Dz  
gqje]Zc<  
System.err.println("文件下载结束!"); lKMOsr@l  
} ;: a>#{N  
catch(Exception e){e.printStackTrace ();} @k!J}O K  
} ]mN'Qoc  
5;5DEMe  
]i-peBxw  
//获得文件长度 `;ofQz4  
public long getFileSize() rSUarfZ<  
{ GN4'LU  
int nFileLength = -1; 3f2%+2Zjt,  
try{ N;9m&)@JR'  
URL url = new URL(siteInfoBean.getSSiteURL()); #-_';Er\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ) /kf  
httpConnection.setRequestProperty("User-Agent","NetFox"); ' {L5 3cH=  
G $TLWfm  
cu4&*{  
int responseCode=httpConnection.getResponseCode(); 8X@p?43  
if(responseCode>=400) \G?GX  
{ 7|IOn5  
processErrorCode(responseCode); *Op;].>E  
return -2; //-2 represent access is error fAu^eS%>7  
} @?$x  
brA\Fp^  
3iHUG^sLW  
String sHeader; R&cOhUj22J  
37hs/=x  
R#ABda9  
for(int i=1;;i++) JC~L!)f  
{ j9@7\N<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0,a;N%K-  
//Utility.log(in.readLine()); R^PPgE6!$  
sHeader=httpConnection.getHeaderFieldKey(i); gAA2S5th  
if(sHeader!=null) 8,Jjv*  
{ v+ NdO$o  
if(sHeader.equals("Content-Length")) T[}A7a6g_  
{ %T hY6y(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]xlV;m  
break; 4!pMZ<$3  
} h01 HX  
} Fb&Xy{kt1  
else N02X*NC  
break; 0j^QY6  
} :Yi1#  
} ^tS{a*Yn  
catch(IOException e){e.printStackTrace ();} Z*EK56.b  
catch(Exception e){e.printStackTrace ();} I%]~]a  
jN\} l|;q  
'u6T^YS  
Utility.log(nFileLength); 3BuG_ild  
_d#1muZ?p|  
gOpi>  
return nFileLength; v+.  n9  
} /;7\HZ$@/  
'D ,efTq  
3;@/`Z_\lt  
//保存下载信息(文件指针位置) 'OI Ol  
private void write_nPos() S+^*rw  
{ >wz& {9ni  
try{ G%{J.J41F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >h^CC*&'pw  
output.writeInt(nStartPos.length); u^DfRd&P0  
for(int i=0;i<nStartPos.length;i++) LUGyc( h  
{ hk =nXv2M  
// output.writeLong(nPos); D# ZzhHHP  
output.writeLong(fileSplitterFetch.nStartPos); {:U zW\5l)  
output.writeLong(fileSplitterFetch.nEndPos); O)y|G%O  
} J<g$hk  
output.close(); k8 !|WqfP  
} #wXq'yi  
catch(IOException e){e.printStackTrace ();} qPEtMvL #  
catch(Exception e){e.printStackTrace ();} E+LAE/v@  
} \qx$h!<  
YP*EDb?f  
D=hy[sDBw  
//读取保存的下载信息(文件指针位置) Y$3 &?LA  
private void read_nPos() !c}?u_Z/  
{ .<0|V  
try{ ]ZV.@% +  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); v6Vieo=  
int nCount = input.readInt(); J!O{.v  
nStartPos = new long[nCount]; a$0,T_wD  
nEndPos = new long[nCount]; Gwyjie9t  
for(int i=0;i<nStartPos.length;i++) [D !-~]5  
{ KIyhvY~  
nStartPos = input.readLong(); Gk<M@d^hQ  
nEndPos = input.readLong(); h^yLmRL  
} =Q\z*.5j.  
input.close(); Rra3)i`*  
} =L,s6J8_'  
catch(IOException e){e.printStackTrace ();} i2. +E&3v  
catch(Exception e){e.printStackTrace ();} #2`ST=#  
} c1!0Z28  
}I3 ZNd   
*C/bf)w  
private void processErrorCode(int nErrorCode) ,t"?~Hl".  
{ 8|Wu8z--  
System.err.println("Error Code : " + nErrorCode); d']CBoK  
} <>=A6  
:{:R5d(_I  
%sd1`1In  
//停止文件下载 O*;$))<wX  
public void siteStop() ZDMv8BP7  
{ Ri[ v(Zf  
bStop = true; DRp h?V\  
for(int i=0;i<nStartPos.length;i++) Mnj\t3:  
fileSplitterFetch.splitterStop(); iLQFce7d|&  
L#t^:%   
$ z4JUr!m  
} 5k%Gj T  
} <OX_6d*@  
//负责部分文件的抓取 ( (.b&  
**FileSplitterFetch.java OvL@@SX |  
*/ K fM6(f:  
package NetFox; Gi=sJV  
qDG{hvl[1r  
Pu|PIdu!08  
import java.io.*; (R'GrN>  
import java.net.*; }> q%##<n  
XH^X4W  
\fX0&l;T9\  
public class FileSplitterFetch extends Thread { K1S:P( S  
gu~JB  
rM?O2n  
String sURL; //File URL :6}Zo  
long nStartPos; //File Snippet Start Position 9'$\GN{0  
long nEndPos; //File Snippet End Position 0m3:!#\  
int nThreadID; //Thread's ID mP!=&u fcU  
boolean bDownOver = false; //Downing is over LS"_-4I}  
boolean bStop = false; //Stop identical s5`CV$bz  
FileAccessI fileAccessI = null; //File Access interface @ Sq =q=S  
prIPPeMdz  
a ~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }s9eRmJs  
{ V-1H(wRu  
this.sURL = sURL; 5|nT5oS  
this.nStartPos = nStart; n(}cK@  
this.nEndPos = nEnd; %-lilo   
nThreadID = id; bD2):U*Fzo  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &ikPa,A  
} D^_]x51>  
B//2R)HS  
p`+=) n  
public void run() [8kufMY|  
{ 'P AIh*qA  
while(nStartPos < nEndPos && !bStop) VVd9VGvh  
{ [6ycs[{!  
OON]E3yy  
*KMW6dg;  
try{ =,MX%-2  
URL url = new URL(sURL); QL].)Vgf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jDO"?@+  
httpConnection.setRequestProperty("User-Agent","NetFox"); [:hTwBRF  
String sProperty = "bytes="+nStartPos+"-"; 4!vovt{  
httpConnection.setRequestProperty("RANGE",sProperty); 4](jV}Hg  
Utility.log(sProperty); =&_Y=>rA]0  
}s@ i  
\!51I./Q/  
InputStream input = httpConnection.getInputStream(); /8cfdP Ba  
//logResponseHead(httpConnection); GbXa=* <-<  
l:@`.'-=  
vtByCu5  
byte[] b = new byte[1024]; &c AFKYt  
int nRead; EDDld6O,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @K=:f  
{ 8|cQW-L  
nStartPos += fileAccessI.write(b,0,nRead); KUV(vAY,  
//if(nThreadID == 1) pW7#&@AR  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TPBL|^3K  
}  Zra P\?  
pu"m(9  
ln1QY"g  
Utility.log("Thread " + nThreadID + " is over!"); M?gc&2 Y  
bDownOver = true; G7qB   
//nPos = fileAccessI.write (b,0,nRead); 3D}rxI8N  
} Ii.?| u  
catch(Exception e){e.printStackTrace ();} PHxU6UPqy  
} FQlYCb  
} C:9a$  
e{Y8m Xu  
Jan~R ran  
//打印回应的头信息 hZwbYvu  
public void logResponseHead(HttpURLConnection con) r|ID]}w  
{ }J^+66{  
for(int i=1;;i++) ZRy'lW  
{ >)j`Q1Qc\  
String header=con.getHeaderFieldKey(i); w/oXFs&FK  
if(header!=null) s7Z+--I)L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _{C =d3  
Utility.log(header+" : "+con.getHeaderField(header)); n40&4n  
else P\rA>ZY  
break; F97HFt6{  
} )c<X.4  
} 3oQ?VP  
v =]!Po&Q-  
/8O;Q~a  
public void splitterStop() UhX)?'J  
{ Zk+c9,q  
bStop = true; %wQE lkB  
} qS!U1R?s  
fG,)`[eD!_  
m\.(-  
} 2:jWO_V@  
Z.%0yS_T  
1$S`>M%a  
/* 2v\<MrL  
**FileAccess.java lD-HQd  
*//文件访问(定位,写) s#p\ r  
package NetFox; Qn!KL0w  
import java.io.*; khb/"VYd  
Gl6M(<f\5  
VBN=xg}  
public class FileAccessI implements Serializable{ <hBd #J  
dcH@$D@~S  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^Z>Nbzr{  
RandomAccessFile oSavedFile; {3qlx1w  
long nPos; &~&oB;uR  
cna/?V  
8#ZF<B Y  
public FileAccessI() throws IOException `gX$N1(  
{ nrM_ay  
this("",0); 9>-]*7  
} .jv#<"DW  
?3yrX _Qm{  
^|lw~F  
public FileAccessI(String sName,long nPos) throws IOException O!k C  
{ kKs}E| T  
oSavedFile = new RandomAccessFile(sName,"rw"); c\.7Z=D  
this.nPos = nPos; lcR1FbJ2'  
oSavedFile.seek(nPos); @=6*]:p2.  
} #/ HQ?3h]  
/=[hRn@)A  
{' UK> S  
public synchronized int write(byte[] b,int nStart,int nLen) 5_[we1$P  
{ S7h?tR*u  
int n = -1; FT Ytf4t  
try{ % pQi}x  
oSavedFile.write(b,nStart,nLen); Zq"  
n = nLen; &Vy.)0  
} ~F.kgX  
catch(IOException e) ZkqZO#nq C  
{ Zv5vYe9Ow  
e.printStackTrace (); giH WC%/  
} zrL+:/t  
q^ eLbivVE  
nC5]IYL|  
return n; VLcwBdo  
} ly::?  
6=p!`DOd  
h'"~t#r  
} hH~GH'dnaE  
62 9g_P)  
=Bos>;dl  
/* 7{Zs"d{s  
**SiteInfoBean.java !7n`-#)  
*/ *:Uq ;)*  
package NetFox; 4G'-"u^g  
z#GrwE,r   
=h\uC).t&  
public class SiteInfoBean { yqKSaPRA  
ziXI$B4-  
N gagzsJ=  
private String sSiteURL; //Site's URL dYZB> OS  
private String sFilePath; //Saved File's Path i}/Het+(  
private String sFileName; //Saved File's Name }t0JI3  
private int nSplitter; //Count of Splited Downloading File ddwokXx (  
B) BR y%  
|e91KmiqJ  
public SiteInfoBean() Ge ?Q)N  
{//nSplitter的缺省值为5 |F49<7XB[~  
//default value of nSplitter is 5 fS]Z`U"  
this("","","",5); /kV5~i<1S  
} qZ%0p*P#_  
yJ*g ;  
m1DrT>oN'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xm0(U0 >  
{ ~Z}DN*S  
sSiteURL= sURL; V?- ]ZkI  
sFilePath = sPath; n um2HtU&%  
sFileName = sName; oC}2 Z{  
this.nSplitter = nSpiltter; c!a1@G  
_Jn@+NoO  
Rnw v/)  
} %+oV-o\ #A  
C1x(4&h  
kZ'wXtBYe  
public String getSSiteURL() S\sy] 1*?$  
{ <_yy0G  
return sSiteURL; Tbj}04;I  
} q{XeRQ'/  
?nwg.&P  
qT^0 %O:  
public void setSSiteURL(String value) "4L_BJZ  
{ y3ST0=>j}  
sSiteURL = value; (!%w  
} ,[[Xo;q  
$pajE^d4V  
3il/{bgM  
public String getSFilePath() 0Om<+]).R  
{ /0r6/ _5-.  
return sFilePath; +8.1cDEH\  
} ~iJ@x;`  
#:=*n(GT  
ok{ F=z  
public void setSFilePath(String value) ?~X^YxWsY  
{ s1J( -O  
sFilePath = value; GHFYIor  
} z}-8pDD'  
p/gf  
0Vj!'=Ntv  
public String getSFileName() p:xVi0  
{ w|:ev_c|  
return sFileName; #kp +e)F  
} %UB+N8x`a  
+TN*6V{D  
Bp/25jy  
public void setSFileName(String value)  #zg"E<  
{ (H-kWT  
sFileName = value; BOme`0A  
} 3-gy)5.x e  
SHQgI<D7  
z q@"qnr  
public int getNSplitter() 9`Xr7gmQf  
{ DI=?{A  
return nSplitter; %JuT'7VB  
} W];l[D<S*  
YXIAVSnr  
-o+; e3#  
public void setNSplitter(int nCount) AS a)xf9  
{ [#2X  
nSplitter = nCount; 5>>JQ2'W  
} s} oD?h:T3  
} `%$+rbo~  
sV`p3L8pl  
i!+0''i{#  
/* <+: PTG/('  
**Utility.java Xj$'i/=-+c  
*/ R_Uy.0=4  
package NetFox; Sz>Lbs  
Hli22~7T:  
Hx NoV.q  
public class Utility { !Aw.)<teW  
R T/)<RT9  
]%+T+ zg(Y  
public Utility() beFD}`  
{ G=&nwSL  
b5W(}ka+  
8b< 'jft  
} !fG}<6&i  
.QB)Y* z  
//线程睡眠 8UXtIuQ  
public static void sleep(int nSecond) "B0I$`~wu  
{ \I7,1I  
try{ FvDi4[F#  
Thread.sleep(nSecond); 2I{kLN1TY  
} U3|9a8^H  
catch(Exception e) ^<Zye>KO  
{ $t.M `:G  
e.printStackTrace (); Zo@  
} N]&:xd5  
} `{xKU8j^  
"f>`ZFp^  
//日志 N ZZc[P  
public static void log(String sMsg) !mK}Rim~  
{ y0,>_MS  
System.err.println(sMsg); MbXtmQ%C8  
} `( _N9.>B  
`W2 o~r*&  
xo#K_"E  
public static void log(int sMsg) B[fbPrM  
{ )^m"fQ+  
System.err.println(sMsg); R+ tQvxp#  
} Rln% Y  
} eDsc_5I  
0+Q; a  
URj2 evYW  
/* K$5mDScoJ  
**TestMethod.java sv2XD}}  
*/ Vj6 w7hz  
package NetFox; l]S%k&  
?fQ8Ff  
~r&+18Z;  
public class TestMethod { 7-d.eNQl  
o`{^ptu1q  
apWv+A  
public TestMethod() 64t:  
{ ///xx/weblogic60b2_win.exe fiW2m=h_  
try{ a=M/0N{!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !G;|~|fMV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]4]AcJj  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =L*-2cE6#  
fileFetch.start(); Z*YS7 ~  
} n,`j~.l-=>  
catch(Exception e){e.printStackTrace ();} 3Hf_!C=g  
_xr@dK<   
U$LI~XZM  
} <J-.,:  
+f'@  
ebhV;Q.  
public static void main(String[] args) zh9B8r)C  
{ SDko#  
new TestMethod(); `Af5%m[  
} X08[,P#I  
} GB}!7W"  
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