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http断点续传简单实现(java)

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/* Gq]d:-7l  
**SiteFileFetch.java ; Zq/eiB  
*/  93w~.p  
package NetFox; 5()Fvae{k  
import java.io.*; k90B!kg  
import java.net.*; MEU[%hty_  
J_  V,XO  
BXTN>d27  
public class SiteFileFetch extends Thread { +Z+ExS<#z  
Fh`-(,e?5  
[b`6v`x  
SiteInfoBean siteInfoBean = null; //文件信息Bean ')nnWlK  
long[] nStartPos; //开始位置 ^Rmoz1d  
long[] nEndPos; //结束位置 ndOfbu;mf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4MX7=!E  
long nFileLength; //文件长度 x N`T  
boolean bFirst = true; //是否第一次取文件 $A?}a  
boolean bStop = false; //停止标志 u@D .i4U  
File tmpFile; //文件下载的临时信息 k!E"wJkpz  
DataOutputStream output; //输出到文件的输出流 .[f;(WR  
|U=(b,  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) jzrt7p*k}  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6An{3 "  
{  `$-lL"  
siteInfoBean = bean; Fp:3#Bh  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :dDxxrs"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }[,3yfiX  
if(tmpFile.exists ()) ~n]NyVFP  
{ ?'2 v.5TQt  
bFirst = false; c)3O/`  
read_nPos(); ahp1!=Z-=  
} t:9 ZCu ay  
else },6*Y*?{  
{ k!13=Gh  
nStartPos = new long[bean.getNSplitter()]; fq Y1ggL  
nEndPos = new long[bean.getNSplitter()]; 3'@&c?F ye  
} pF='jj51  
pbdF]>\  
8_iHVc;<  
t F/nah  
} #>q[oie1e  
W uf/LKj  
I*c;hfu  
public void run() BkT-m'I?  
{ Opry`}5h  
//获得文件长度 CZfE |T~  
//分割文件 b"P&+c  
//实例FileSplitterFetch a4u^f5)@  
//启动FileSplitterFetch线程 s]bPV,"p  
//等待子线程返回 #PH#2/[  
try{ ]BfR.,,  
if(bFirst) {_as!5l  
{ b_ JWnh  
nFileLength = getFileSize(); bm6hZA|  
if(nFileLength == -1) <_f`$z  
{ f+^c@0que  
System.err.println("File Length is not known!"); xOM_R2Md  
} .Qk{5=l6P  
else if(nFileLength == -2) `]hCUaV   
{ =phiD&=  
System.err.println("File is not access!"); `5<1EGJsD  
} HPTHF  
else "GLYyC  
{ \^m.dIPdO  
for(int i=0;i<nStartPos.length;i++) LT(?#)D  
{ TMY{OI8a  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &oc_ a1 R  
} 5U;nhDmM  
for(int i=0;i<nEndPos.length-1;i++) r./z,4A`  
{ #4q1{)=  
nEndPos = nStartPos[i+1]; gA"<MI'y  
} +{Gw9h"5g*  
nEndPos[nEndPos.length-1] = nFileLength; N&N 82OG  
} <O bHf`Q  
} M1gP R  
kDg{ >mf  
wXcMt>3  
//启动子线程 :o<N!*pT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; H8<m9zDvl  
for(int i=0;i<nStartPos.length;i++) !?n50  
{ h=Oh9zsz8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }8 \|1@09  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J 5- rp|  
nStartPos,nEndPos,i); F_ _H(}d  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mf~Lzp  
fileSplitterFetch.start(); X,&xhSzg?  
} -sx-7LKi  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VlV)$z_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); < %/:w/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tPzM7 n|  
nEndPos = " + nFileLength); bCt_y R  
// fileSplitterFetch[nPos.length-1].start(); 6yp+h  
W'd/dKU x  
oX#9RW/ >I  
//等待子线程结束 -P*xyI  
//int count = 0; 9g4QVo|  
//是否结束while循环 jvWI_Fto  
boolean breakWhile = false; LEA;dSf  
&E`9>&~J  
8`DO[Z  
while(!bStop) pB[%:w/@l:  
{ Q{8qm<0g  
write_nPos(); SUo^c1)G  
Utility.sleep(500); rEg+i@~  
breakWhile = true; <gR`)YF7  
bt0djJRw  
Gk{W:866  
for(int i=0;i<nStartPos.length;i++) V!H(;Tuuo  
{ |O%:P}6c  
if(!fileSplitterFetch.bDownOver) O<bDU0s{M  
{ %OuX`w=  
breakWhile = false; )2#vhMpdN  
break; .r(^h/IF  
} h1E PaL  
} 2[XltjO  
if(breakWhile) 0&f\7z  
break; ~DK F%}E  
}]tFz}E\  
Bmmb  
//count++; :mzCeX8 *  
//if(count>4) #fO*ROe  
// siteStop(); QZ?O;K1|y  
} Euqjxz  
`~0P[>|+  
zU=YNrn  
System.err.println("文件下载结束!"); zLo;.X[Y  
} KxGKA  
catch(Exception e){e.printStackTrace ();} m\/>C|f\  
} R9bhC9NP  
tx gvVQ  
NYGmLbq  
//获得文件长度 <&KLo>B^  
public long getFileSize() /cM 5  
{ ^zKt{a  
int nFileLength = -1; U2VV[e)Z!  
try{ B<(Pd  
URL url = new URL(siteInfoBean.getSSiteURL()); omNpE_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _w\Y{(k  
httpConnection.setRequestProperty("User-Agent","NetFox"); q"P5,:W  
_s2m-jm7  
#aj|vox}  
int responseCode=httpConnection.getResponseCode(); Ii,~HH  
if(responseCode>=400) q^)=F_QvG  
{ p1Y+  
processErrorCode(responseCode); b{zAJ`|#[n  
return -2; //-2 represent access is error -3u@hp_  
} /rn"  
vU?b"n  
!T)T_P[  
String sHeader; Ng?apaIi@~  
|)m*EME  
#,7eQaica  
for(int i=1;;i++) n9N#&Q"7m  
{ PbbXi  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +Gk! t]dy  
//Utility.log(in.readLine()); '2 w XV;`  
sHeader=httpConnection.getHeaderFieldKey(i); ,}eRnl\  
if(sHeader!=null) sM #!Xl;  
{ V h Z=,m  
if(sHeader.equals("Content-Length")) .WBI%ci  
{ ;Fx')  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); j2< !z;2  
break; eo>/  
} dCa}ITg  
} [q|?f?Zl  
else |\i:LG1  
break; V"w`!  
} -iY9GN89c  
} w> Tyk#7lw  
catch(IOException e){e.printStackTrace ();} IOSuaLH^  
catch(Exception e){e.printStackTrace ();} k&MlQ2'!<  
ox!|)^`$_  
JR H f.?  
Utility.log(nFileLength); <$RS*n  
_8,vk-,'  
j l;kcGE  
return nFileLength; 9@$tiDV  
} *p""YEN  
Wv6z%r<  
CPc"  
//保存下载信息(文件指针位置) >2]Eaw&W  
private void write_nPos() dE 3i=  
{ *37LN  
try{ "bHtf_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); V}vl2o  
output.writeInt(nStartPos.length); %GVEY  
for(int i=0;i<nStartPos.length;i++) [ c ~LY4:  
{ H.jLGe>  
// output.writeLong(nPos); [$hptQv  
output.writeLong(fileSplitterFetch.nStartPos); f28gE7Y\a  
output.writeLong(fileSplitterFetch.nEndPos); f?/|;Zo4  
} /Ki0+(4  
output.close(); @ChN_gd3!  
} DQ}_9?3  
catch(IOException e){e.printStackTrace ();} @4G.(zW  
catch(Exception e){e.printStackTrace ();} X{0ax.  
} }}kS~ w-#  
a) I=U [  
C ffTv  
//读取保存的下载信息(文件指针位置) 7yMieUF  
private void read_nPos() OVDMC4K2z!  
{ _7-"Vo X  
try{ QV nO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |#DC.Ga!  
int nCount = input.readInt(); O!#L#u53  
nStartPos = new long[nCount]; \SYPu,ZT  
nEndPos = new long[nCount]; <7vIh0  
for(int i=0;i<nStartPos.length;i++) &,m'sQ  
{ I>< 99cwFI  
nStartPos = input.readLong(); yRgDhA  
nEndPos = input.readLong(); W /~||s  
} w,M1`RsK  
input.close(); JxX jDYrU  
} o{ ,ba~$.w  
catch(IOException e){e.printStackTrace ();} R-g>W  
catch(Exception e){e.printStackTrace ();} !~Hafn-1  
} (hhdbf  
4FfwpO3,Ku  
J]n7| L  
private void processErrorCode(int nErrorCode) lU&`r:1>_  
{ "@c';".|  
System.err.println("Error Code : " + nErrorCode); ?#VP)A  
} y9V;IXhDc  
"ay,Lr  
/7UovKKbz  
//停止文件下载 q;1VF;<"vH  
public void siteStop() oiTMP`Y  
{ ]>VJ--fH  
bStop = true; RT.wTJS;  
for(int i=0;i<nStartPos.length;i++) WU+Jo@]y  
fileSplitterFetch.splitterStop(); |x _ -I#H  
!7O=<  
yS:IRI.  
} FT|/ WZR  
} pO-s@"j]  
//负责部分文件的抓取 eHF(,JI  
**FileSplitterFetch.java ~>Hnf_pZO  
*/ 1+16i=BF)  
package NetFox; 6T{o3wc;  
L]/\C{}k  
]X >QLD0W  
import java.io.*; wzNt c)~i  
import java.net.*; bMK#^ZoH  
Y\z^\k  
,p[\fT($]  
public class FileSplitterFetch extends Thread { \,@Yl.,+  
Ov~S2?E8  
Rk437vQD,  
String sURL; //File URL \dp9@y[^  
long nStartPos; //File Snippet Start Position 'gk81@|  
long nEndPos; //File Snippet End Position zJy 89ib'  
int nThreadID; //Thread's ID 4'}_qAT  
boolean bDownOver = false; //Downing is over ijZydn  
boolean bStop = false; //Stop identical =u:6b} =  
FileAccessI fileAccessI = null; //File Access interface ]AFM Y<mB  
l ))~&  
ch)Ps2i  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )"pxry4v7J  
{ ReHd~G9  
this.sURL = sURL; >'2w\Uk~:  
this.nStartPos = nStart; UgnsV*e&  
this.nEndPos = nEnd; W[1f]w3  
nThreadID = id; RAv RNd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (N~zJ .o  
} JEm?26n X  
'1kj:Np  
:N+#4rtgUY  
public void run() .qb_/#Bas  
{ <u x*r#a!d  
while(nStartPos < nEndPos && !bStop) {d?4;Kd  
{ |ZST Y}RXA  
'n>3`1E,  
J1c&"Oh  
try{ ,/w852|ub  
URL url = new URL(sURL); g'}`FvADi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u]]5p[ |S  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7fN&Q~.  
String sProperty = "bytes="+nStartPos+"-"; #g-*n@ 1  
httpConnection.setRequestProperty("RANGE",sProperty); PPj6QJ]R0  
Utility.log(sProperty); (Qh7bfd  
A&}nRP9  
Ch \ed|u  
InputStream input = httpConnection.getInputStream(); 0ez i?Um  
//logResponseHead(httpConnection); aoakTi!}  
y-)+I<M  
a' >$88tl  
byte[] b = new byte[1024]; x^='pEt{  
int nRead; LjH&f 4mY  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qV,$bw  
{ y 8d`},  
nStartPos += fileAccessI.write(b,0,nRead); Zjp5\+hHV  
//if(nThreadID == 1) >QZt)<[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OB*Xb*HN  
} ax{-Qi7z-+  
lU50.7<08  
Wf`Oye Rz  
Utility.log("Thread " + nThreadID + " is over!"); :#W>SO  
bDownOver = true; Hs4zJk  
//nPos = fileAccessI.write (b,0,nRead); ?%za:{  
} r"u(!~R  
catch(Exception e){e.printStackTrace ();} 'Qs 3  
} !s[j1=y  
} 6(<~1{ X%  
iM\ Z J6  
Y9H *S*n  
//打印回应的头信息 vRb(eg  
public void logResponseHead(HttpURLConnection con) tN'- qdm  
{ (;Q <@PZg  
for(int i=1;;i++) &6|^~(P?  
{ {HRxyAI!  
String header=con.getHeaderFieldKey(i); dl7p1Cr  
if(header!=null) *F8 uu.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); a9@l8{)RX  
Utility.log(header+" : "+con.getHeaderField(header)); ".Deu|>  
else K3r>nGLBo  
break; dn)tP6qc/  
} H:{(CY?t  
} k+Ma_H`  
i:Z.;z$1  
QhE("}1  
public void splitterStop() ]N(zom_0d  
{ Dpp52UnT E  
bStop = true; T`'3Cp$q  
} d$?n6|4  
*l?% o{  
_"w!KNX>(~  
} I|3v&E 1  
T\e)Czz2-  
s<r.+zqW  
/* _KkVI7a  
**FileAccess.java RJ@e5A6_  
*//文件访问(定位,写) |_xiG~  
package NetFox; G`9F.T_Z^)  
import java.io.*; IrwF B  
h&)vdCCk  
.IAHy)li"  
public class FileAccessI implements Serializable{ LWb}) #E  
CQuvbAo  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 milK3+N  
RandomAccessFile oSavedFile; |z7Crz  
long nPos; CIik@O*  
;,B@84'  
E?q'|f  
public FileAccessI() throws IOException 1'U%7#;E  
{ p_40V%y^  
this("",0); "6NNId|Y  
} (zLIv9$  
,cO)Sxj  
$ p1EqVu  
public FileAccessI(String sName,long nPos) throws IOException 2,e|,N"zN  
{ |xgCV@  
oSavedFile = new RandomAccessFile(sName,"rw"); 8H`l"  
this.nPos = nPos; qyBK\WqaP  
oSavedFile.seek(nPos); )J6b:W  
} 9B;Sk]y  
eP'kY(g8   
VU'l~%ql  
public synchronized int write(byte[] b,int nStart,int nLen) JK8@J9(#  
{ (PrPH/$  
int n = -1; <ZvPtW  
try{ +U/"F|M  
oSavedFile.write(b,nStart,nLen); Lp]C![\>U  
n = nLen; (uK), *6B  
} -K'84 bZ  
catch(IOException e) p*&LEjaVM4  
{ :ktX7p~  
e.printStackTrace (); !/(}meZj  
} TtjSLkF  
eWk2YP!  
B)cb}.N:  
return n; NizJq*V>  
} 98}vbl31j  
6=lQT 9u{  
S+xGHi)  
} ? A#z~;X@  
:pjK\  
eD1MP<>h  
/*  p|8Fl  
**SiteInfoBean.java rHdP4:n  
*/ WI 4_4  
package NetFox; |Gs-9+'y  
2?nyPqT3AM  
:@8.t,|  
public class SiteInfoBean { ! tPK"k  
1:s~ ]F@  
;Wh[q*A  
private String sSiteURL; //Site's URL [^=8k2  
private String sFilePath; //Saved File's Path `IRT w"  
private String sFileName; //Saved File's Name ?&nz  
private int nSplitter; //Count of Splited Downloading File +~{nU'  
0m!ZJHe  
dZYJ(7%  
public SiteInfoBean() ^Jpd9KK  
{//nSplitter的缺省值为5 >)Z2bCe  
//default value of nSplitter is 5 4_:e+ ql  
this("","","",5); td$6:)  
} xENA:j?kF  
44{:UhJkx  
s ;Nu2aOp7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) XUNgt(OGR'  
{ 5h^qtK  
sSiteURL= sURL; (9_e >2_  
sFilePath = sPath;  F%$Ws>l  
sFileName = sName; 00wH#_fm  
this.nSplitter = nSpiltter; ]Oh>ECA|D  
CrX-?$  
?iO^b.'I#  
} 7IW7'klkvD  
\mit&EUh}  
A_ z:^9  
public String getSSiteURL() p 8Hv7*  
{ Y tj>U  
return sSiteURL; ] r+I D  
} 2xBGs9_Y  
JJOs L!@  
|Qq'_4:  
public void setSSiteURL(String value) ^n5QK HD  
{ vjWgR9 4/{  
sSiteURL = value; g8@HAV^H  
} )tg*dE  
.shI% 'V  
Ds5&5&af  
public String getSFilePath() HY#("=9< h  
{ 8(K~QvE~  
return sFilePath; ]@]"bF!Dn  
} t$D[,$G9  
]>!_OCe&  
2YEn)A@8  
public void setSFilePath(String value) . k DCcnm  
{ ]V\ g$@  
sFilePath = value; 52Ffle8  
} $}o,7xAn  
yG_.|%e  
?& ^l8gE  
public String getSFileName() $k=rd#3  
{ l%w|f`B:  
return sFileName; Jq@LZ2^  
} .qP zd(<T7  
n8C {Okr  
!}m 8]&  
public void setSFileName(String value) }E_zW.{!  
{ KDzIarC  
sFileName = value; 7cSvAX0Z.  
} 0drc^rj !  
>CA1Ub&ls  
M/ \~  
public int getNSplitter() BNLall  
{ P l ,M>IQ  
return nSplitter; _+7f+eB  
} N#qoKY(#  
wOSNlbQ5jl  
O3^@"IY  
public void setNSplitter(int nCount) O$\N]#  
{ wIPDeC4  
nSplitter = nCount; VJPPHJ[-  
} UcIR0BYa  
} ku=q:ry O  
zy5bDL -  
C u5 - w  
/* 7k3\_BHyb\  
**Utility.java ";%1sK  
*/ $x<-PN  
package NetFox; {GY$J<5=  
L>*|T[~  
;!Mg,jlQ  
public class Utility { ttxOP  
hTqJDP"&F  
Cr"hu;  
public Utility() svII =JB  
{ Xp@OIn  
{rr\hl-$  
E_#&L({|@  
} R2gax;  
m{" zFD/  
//线程睡眠 fe,CY5B{  
public static void sleep(int nSecond) x6]?}Q>>D  
{ !ym5' h  
try{ ng\S%nA&J  
Thread.sleep(nSecond); U$%w"k7^(  
} Il[WXt<S  
catch(Exception e) $NSYQF%aO  
{ O5"80z38[  
e.printStackTrace (); VzNH%  
} r,\(Y@I  
} hy rJu{p  
pwQ."2x  
//日志 v?t+%|dzA  
public static void log(String sMsg) MsiSC  
{ n%hnL$!z  
System.err.println(sMsg); vOU -bF%u  
} ekXHfA!i%  
l K%Hb=  
a$-ax[:\sm  
public static void log(int sMsg) _t7A'`Dh]  
{ g.qp _O  
System.err.println(sMsg); 23m+"4t  
} Obm\h*$  
} [\y>Gv%  
TW$^]u~v  
G{9y`;  
/* {0~ p"%*  
**TestMethod.java  G%{jU'2  
*/ fzcT(y  
package NetFox; Xb {y*',  
q}lSnWY[[  
HvU)GJ u b  
public class TestMethod { yCVBG  
hvwr!(|W  
)XWL'':bF  
public TestMethod() :8FH{sqR  
{ ///xx/weblogic60b2_win.exe z%z$'m  
try{ +xa2e?A%L  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YrX{,YtiX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6kk(FVX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); sT ONkd  
fileFetch.start(); 3FfS+q*3S  
} p_( NLJ%  
catch(Exception e){e.printStackTrace ();}  lwlR"Z  
Wh7nli7f_  
%$U+?lk}  
} {$JIR}4S  
>ZT3gp?E  
uFgw eOJ  
public static void main(String[] args) 6/ )A6Tt  
{ x :s-\>RcA  
new TestMethod(); U-d&q>_@A  
} aE}u5L$#  
} {Ffr l(*  
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