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http断点续传简单实现(java)

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/* F:7 d}Jx  
**SiteFileFetch.java "%I<yUP]U  
*/ {k}$L|w  
package NetFox; *3iEO>  
import java.io.*; O\J{4EB@.  
import java.net.*; +lplQh@RB  
sEymwpm9  
YMn*i<m  
public class SiteFileFetch extends Thread { [CG3&J  
KPjC<9sby  
u']}Z% A9`  
SiteInfoBean siteInfoBean = null; //文件信息Bean p!o-+@ava  
long[] nStartPos; //开始位置 {nPiIPH  
long[] nEndPos; //结束位置 v\lKY*@f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 I:6H65(&  
long nFileLength; //文件长度 `O0bba=:=  
boolean bFirst = true; //是否第一次取文件 SPT?Tt  
boolean bStop = false; //停止标志 ??#SQSU  
File tmpFile; //文件下载的临时信息 V_3K((P6  
DataOutputStream output; //输出到文件的输出流 _I?oR.ON33  
gb{8SG5ac  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) :\Q#W4~p  
public SiteFileFetch(SiteInfoBean bean) throws IOException e_YTh^wU  
{ &#zx/$  
siteInfoBean = bean; FLo`EE":O(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]T<tkvcI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); M3G ecjR  
if(tmpFile.exists ()) m Ce"=[  
{ w8D6j%C  
bFirst = false; :al ,zxs  
read_nPos(); ,! H`@Kl  
} D"msD"  
else ,!O]c8PcU  
{ 4V&(w, zl  
nStartPos = new long[bean.getNSplitter()]; SM8f"H28  
nEndPos = new long[bean.getNSplitter()]; >fi_:o  
} )g?ox{Hol  
]JR2Av  
1'!D   
:b0|v`FU  
} .?`8B9w  
m[CyvcF*u  
B.C:06E5  
public void run() <A(Bq'eQM  
{ !k Heslvi  
//获得文件长度 pAws{3(Q  
//分割文件 2w}l!'ue  
//实例FileSplitterFetch GG`j9"t4  
//启动FileSplitterFetch线程 _+j#.o>  
//等待子线程返回 E!RlH3})  
try{ 99tUw'w  
if(bFirst) ix hF,F  
{ =9h!K:,k  
nFileLength = getFileSize(); 6 w'))Z  
if(nFileLength == -1) klAvi%^jE  
{ '|<r[K  
System.err.println("File Length is not known!"); .}5qi;CA  
} ~h:(9q8NLC  
else if(nFileLength == -2) v@4vitbG9  
{ :='I>Gn  
System.err.println("File is not access!"); Z,tHyyF?j  
} "ql$Rz8  
else o%!s/Z1  
{ l"1*0jgBw  
for(int i=0;i<nStartPos.length;i++) D\Y,2!I  
{ n[B[hAT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <#wVQ\0C  
} R$p(5>#\5  
for(int i=0;i<nEndPos.length-1;i++) DheQcM  
{ 6RG63+G  
nEndPos = nStartPos[i+1]; ,^7] F"5  
} VsJKxa4  
nEndPos[nEndPos.length-1] = nFileLength; FJ{/EloF  
} &2Ef:RZF  
} wPX^P  
O^PN{u  
_e/Bg~  
//启动子线程 CpB,L  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; YG /@=Z.  
for(int i=0;i<nStartPos.length;i++) n.i 8?:  
{ .SLpgYFL{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (xE |T f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /M JI^\CA  
nStartPos,nEndPos,i); /~Bs5f.]?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); MsZx 0]  
fileSplitterFetch.start(); $o0.oY#  
} IT7],pM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FUf.3@}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9)8Cf% <(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &6vWz6!P  
nEndPos = " + nFileLength); +$Y*1{hyOo  
// fileSplitterFetch[nPos.length-1].start(); h$}PQ   
B&7NF}CF2  
dVk(R9 8  
//等待子线程结束 QJ(5o7Tfn  
//int count = 0; f5p/cUzX  
//是否结束while循环 61b*uoq0w?  
boolean breakWhile = false; MsBm0r`a  
U{j4FlB  
D.-G!0!  
while(!bStop) >28l9U  
{ "h #/b}/  
write_nPos(); ?"^{:~\N  
Utility.sleep(500); lSBR(a<\y  
breakWhile = true; p_ f<@WE  
9^9-\DG  
(@qPyM6~}  
for(int i=0;i<nStartPos.length;i++) Y mL{uV$  
{ zVa&4 T-  
if(!fileSplitterFetch.bDownOver) ,q>cFsY=i?  
{ `GkCOx,  
breakWhile = false; a#{"3Z2|  
break; :b*7TJ\grN  
} :|$cG~'J  
} V2|By,.  
if(breakWhile) {F2Rv  
break; e&2,cQRFV  
Te[v+jgLY,  
W/%hS)75  
//count++; [& Z- *a  
//if(count>4) 1r};cY6  
// siteStop(); @?3^ Ks_  
} fm@Pa} ,  
_5H~1G%q  
(~%NRH<\  
System.err.println("文件下载结束!"); [u$|/  
} i39ZBs@  
catch(Exception e){e.printStackTrace ();} <i4]qO(0u  
} 6%h%h: e  
Ov<c1y;f  
'l=>H#}<B  
//获得文件长度 $8i`h}AM  
public long getFileSize() Z'>UR.g  
{ ;HH%OfQq  
int nFileLength = -1; G<=I\T'g;  
try{ Y<u%J#'[  
URL url = new URL(siteInfoBean.getSSiteURL()); p"c6d'qe  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k*n~&y:O  
httpConnection.setRequestProperty("User-Agent","NetFox"); u z7|!G!43  
6dmb bgO)  
b_a k@LYiu  
int responseCode=httpConnection.getResponseCode(); UWEegFq*  
if(responseCode>=400) U65l o[  
{ :IBP "  
processErrorCode(responseCode); \O4s0*gw  
return -2; //-2 represent access is error ]hS<"=oj  
} w|]Tt="   
*;9H\%  
vanV|O  
String sHeader; [5p3:D  
l"(PP3  
Gp \-AwE  
for(int i=1;;i++) \Cu=Le^  
{ k(pJVez  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1;1;-4k7I  
//Utility.log(in.readLine()); Y JMs9X~3  
sHeader=httpConnection.getHeaderFieldKey(i); l"A/6r!Dp  
if(sHeader!=null) Exqz$'(W9  
{ 7%EIn9P  
if(sHeader.equals("Content-Length")) wM4{\  f\  
{ qqe"hruFJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .B- b51Uz  
break; $u.rO7)  
} Z^2SG_pD  
} x?V^ l*  
else 3vcyes-U  
break; Pg8boN]}  
} OblHN*  
} ;l _b.z0^6  
catch(IOException e){e.printStackTrace ();} 6WQN !H8+^  
catch(Exception e){e.printStackTrace ();} =oIt.`rf  
?g{[U0)  
\Xmp lG:  
Utility.log(nFileLength); k kAg17 ^  
{q`8+$Z;  
>n3GvZ5%  
return nFileLength; &gruYZGK  
} V\x'w*FP  
2,q*8=?{6P  
?k4Hk$V  
//保存下载信息(文件指针位置) dp^PiyL  
private void write_nPos() \fEG5/s}T  
{ D{Nd2G  
try{ nvf5a-C+q  
output = new DataOutputStream(new FileOutputStream(tmpFile));  mjP  
output.writeInt(nStartPos.length); |Vqm1.1/Zv  
for(int i=0;i<nStartPos.length;i++) zHz>Gc  
{ &WBpd}|+Y  
// output.writeLong(nPos); 2<5LQr  
output.writeLong(fileSplitterFetch.nStartPos); )L6 it  
output.writeLong(fileSplitterFetch.nEndPos);  ..E_M$}  
} 9ybR+dGm+  
output.close(); M j[+h|e  
} ;Us6:}s  
catch(IOException e){e.printStackTrace ();} "lu^  
catch(Exception e){e.printStackTrace ();} Bo8f52|  
} Z(tJd ,  
0.wF2!V.  
D((/fT)eD  
//读取保存的下载信息(文件指针位置) 6Aqv*<1=62  
private void read_nPos() -XL? n/M  
{ =23B9WT   
try{ KTT!P 4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); BM:p)%Pv#P  
int nCount = input.readInt(); d*Su c  
nStartPos = new long[nCount]; /nA>ox78  
nEndPos = new long[nCount]; AZhI~QWo  
for(int i=0;i<nStartPos.length;i++) { 'A 15  
{ yN{**?b  
nStartPos = input.readLong(); jZqa+nG51  
nEndPos = input.readLong(); [dP<A ?s  
} ]~dB| WB  
input.close(); ,&4 [`d  
} 8 A]8yX =  
catch(IOException e){e.printStackTrace ();} hz;SDaBA  
catch(Exception e){e.printStackTrace ();} Od;k}u6;<  
} @w==*.x  
#e-7LmO~  
paD[4L?4Hk  
private void processErrorCode(int nErrorCode) OfBWf6b  
{ aC1 xt(  
System.err.println("Error Code : " + nErrorCode); <:/aiX8  
} v"(6rZsa  
#S/~1{   
hlV(jz  
//停止文件下载 /G7^l>pa  
public void siteStop() ,Aq, f$5V  
{ c/bT5TIEWs  
bStop = true; 6Zw$F3 <  
for(int i=0;i<nStartPos.length;i++) u;^H=7R  
fileSplitterFetch.splitterStop(); [= E=H*j  
}])j>E  
[7`S`\_NK  
} Pfvb?Hy  
} uv$5MwKU  
//负责部分文件的抓取 M^ WoV }'  
**FileSplitterFetch.java |n,O!29  
*/ u"v$[8  
package NetFox; "[["naa  
9mMQ  
B &Z0ZWx  
import java.io.*; =r]_$r%gR  
import java.net.*; oSMIWwg7G  
F'{T[MA  
ZT&[:>upR  
public class FileSplitterFetch extends Thread { Uhh[le2 %  
j^ 8Hjg  
7SkW!5  
String sURL; //File URL N/{=j  
long nStartPos; //File Snippet Start Position MJe/ \  
long nEndPos; //File Snippet End Position ?cz7s28a  
int nThreadID; //Thread's ID rS\mFt X  
boolean bDownOver = false; //Downing is over 8sDw:wTC  
boolean bStop = false; //Stop identical :+_H%4+  
FileAccessI fileAccessI = null; //File Access interface Z] cFbl\ma  
M-QQ  
b9.7j!W  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException epk C '  
{ 8[^b8^  
this.sURL = sURL; E]a,2{&8<  
this.nStartPos = nStart; j y p.2c  
this.nEndPos = nEnd; DP*V|)  
nThreadID = id; r H9}VA:h  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 T^|6{ S\  
} iuEe#B;!  
gEVoY,}/-U  
k~<ORnda  
public void run()  5 YIk  
{ <Vyl*a{%  
while(nStartPos < nEndPos && !bStop)  /*S6/#  
{ p0Ij 4   
'#lEUlB  
t2.]v><  
try{ GZ:1bV37%  
URL url = new URL(sURL); M#],#o*G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [e.`M{(TB  
httpConnection.setRequestProperty("User-Agent","NetFox"); y>UQm|o<W  
String sProperty = "bytes="+nStartPos+"-"; /WAOpf5  
httpConnection.setRequestProperty("RANGE",sProperty); W-RshZ\  
Utility.log(sProperty); %I)*5M6  
+Sv2'& B  
Sf`?j  
InputStream input = httpConnection.getInputStream(); ]Ah<kq2sk  
//logResponseHead(httpConnection); &s.-p_4w^D  
0[Zs8oRiI  
"\afIYS I  
byte[] b = new byte[1024]; J(,gLl  
int nRead; QA!'p1{#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) M|z4Dy  
{ bq5?fPBrq  
nStartPos += fileAccessI.write(b,0,nRead); x*^)B~7}  
//if(nThreadID == 1) ir )~T0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Vc|QW  
} Mm"0Ip2"  
+{ e2TY  
G"<} s mB  
Utility.log("Thread " + nThreadID + " is over!"); ~|wh/]{b9  
bDownOver = true; Xdf;'|HO  
//nPos = fileAccessI.write (b,0,nRead); %8% 0l*n'  
} _32 o7}!x  
catch(Exception e){e.printStackTrace ();} !| GD8i  
} =WFG[~8  
} #)%dG3)e  
+N:M;uTS  
)!`>Q|]}Zd  
//打印回应的头信息 /EM=!@ka  
public void logResponseHead(HttpURLConnection con) 5=_))v<Tp  
{ 'khhn6itA  
for(int i=1;;i++) ? i|LO  
{ 5m6I:s`pK  
String header=con.getHeaderFieldKey(i); RjR  
if(header!=null) r<kqs,-~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7LW %:0  
Utility.log(header+" : "+con.getHeaderField(header)); _vE[TFy  
else ~{yQsEU  
break; "g;}B"rG  
} za4:Jdr  
} V@ph.)z  
=G/`r!r*0I  
H 4W4# \M  
public void splitterStop() n<7R6)j6  
{ QW@`4W0F  
bStop = true; 1QuR7p  
} -+|{#cz  
]M9r<x*  
ZEU/6.  
} ^5gB?V,  
|f&=9%  
{B6tGLt#bf  
/* `OyYo^+D|.  
**FileAccess.java Rwz (20n\^  
*//文件访问(定位,写) Q(YQ$ i"S  
package NetFox; (=i+{ 3`|  
import java.io.*; DKf:0E8  
OOX}S1lA  
Q pbzx/2h  
public class FileAccessI implements Serializable{ Wp$'#HhB  
3HmJixy  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 'St\$X  
RandomAccessFile oSavedFile; m&r?z%  
long nPos; [mI;>q  
M)CE%/P  
|/35c0IM  
public FileAccessI() throws IOException y 4jelg  
{ S A16Ng  
this("",0); uzUZuJ  
} GSu&Z/Jo  
s3l:ST  
2l!* o7  
public FileAccessI(String sName,long nPos) throws IOException zINziAp{  
{ {B lM<  
oSavedFile = new RandomAccessFile(sName,"rw"); G^Yg[*bJ^$  
this.nPos = nPos; &ffd#2f`@  
oSavedFile.seek(nPos); q--;5"=S  
} >NN&j#;x~  
r$Ck:Q}  
}xM >F%  
public synchronized int write(byte[] b,int nStart,int nLen) p8MPn>h<  
{ 4ky@rcD1  
int n = -1; 2f$6}m'Ad  
try{ </8F  
oSavedFile.write(b,nStart,nLen); J'>i3e Lq  
n = nLen; :vJ0Ypz-u  
} (>Tq  
catch(IOException e) g!`$bF=e  
{ T"$yh2tSY  
e.printStackTrace (); m2"~.iM8  
} nXOJ  
${F] N }  
/!Ng"^.e  
return n; %7~~*_G  
} I=I'O?w  
!* C9NX  
<);Nc1  
} $R[ggH&  
AR-&c 3o  
AGxG*KuZ  
/* #2023Zo]  
**SiteInfoBean.java wfxg@<WR  
*/ Z>H y+Q4  
package NetFox; \{ui{8+G  
nZ 0rxx[V?  
U&\8~h  
public class SiteInfoBean { <X_I`  
3o=K?eOdg  
;:l\_b'Z}  
private String sSiteURL; //Site's URL >~sAa+Oxi  
private String sFilePath; //Saved File's Path >)3[CU,  
private String sFileName; //Saved File's Name ,1+)qv#|i  
private int nSplitter; //Count of Splited Downloading File $fwv'  
2%Y]M%P  
AI&Bv  
public SiteInfoBean() T~rPpi&  
{//nSplitter的缺省值为5 `'{>2d%\g  
//default value of nSplitter is 5 Q,mmHw.`J  
this("","","",5); q^_PR|  
} v} $KlT  
p=65L  
}qf)L .  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .*s1d)\:  
{ dt(#|8i%  
sSiteURL= sURL; Rx22W:S=C.  
sFilePath = sPath; Ok=RhoZZ  
sFileName = sName; CN$wlhs  
this.nSplitter = nSpiltter; ljij/C=  
DhwFD8tT  
RTW4r9~'  
} :! h1S`wS  
^Z{W1uYi  
A@X&d y  
public String getSSiteURL() .*N,x0 B(  
{ E  K)7g~  
return sSiteURL; VE<&0d<  
} m\88Etl@  
o#-K,|-  
+d0&(b  
public void setSSiteURL(String value) \WnI&nu  
{ J<<0U;  
sSiteURL = value; <= xmJx-V  
} +|N!(H  
>+w(%;i;  
,3t('SE  
public String getSFilePath() 8()L}@y  
{ 8T:|~%Sw  
return sFilePath; n\#RI9#\  
} \/J7U|@Lt  
yE(>R(^  
a+TlZE>8  
public void setSFilePath(String value) q89#Ftkt  
{ ztNm,1pnQ  
sFilePath = value; `43`*=  
} 8Q&hhmOnz  
wr/Z)e =^3  
][|)qQ%V  
public String getSFileName() meHAa`  
{ ]E1aIt  
return sFileName; Qo !/]\  
} CF`tNA3fxm  
ik@g;>pQD  
MVW2 %6  
public void setSFileName(String value) 7T]}<aK<c[  
{ dsKEWZ =  
sFileName = value; z:hY{/-  
} ZqHh$QBD 9  
.D^=vuxt~  
7(m4,l+(  
public int getNSplitter() *<yKT$(+_  
{ QfuKpcT &  
return nSplitter; d~](S<k  
} ^FJ=/#@T  
;&Q8xC2  
$d4^e&s  
public void setNSplitter(int nCount) uP\?y(= "  
{ }b-"[TDEF  
nSplitter = nCount; FqOV/B /z2  
} Y|t]bb  
} bJJB*$jW=  
m L#-U)?F  
[-X=lJ:+h  
/* }JXAG/<  
**Utility.java #%4-zNS  
*/ jg]_'^pVzr  
package NetFox; [:x^ffs  
>5{Z'UWxh  
[HJ^'/bB'  
public class Utility { >yC1X|d~t  
+$KUy>  
Np4';H  
public Utility() Hmt} @  
{ DBuvbq-  
KJPCO0"  
\$Xo5f<  
} 12\h| S~  
!Pf_he  
//线程睡眠 <0OZ9?,dm  
public static void sleep(int nSecond) >=|Dir  
{ 6Y^UC2TBs  
try{ }Yt/e-Yg%r  
Thread.sleep(nSecond); CA7ZoMB#  
} hr&&"d {s  
catch(Exception e) m}\G.$h4  
{ p2N;-  
e.printStackTrace (); D[2I_3[wp  
} 3fJ GJW!zu  
} f>k<I[C<  
]iewukB4  
//日志 isaDIl;L/  
public static void log(String sMsg) NIcPjo  
{ xS%Z   
System.err.println(sMsg); .lVC>UT  
} jM8e2z3  
lwEJ)Bv  
99%oY  
public static void log(int sMsg) }5~|h%  
{ nUi 4!|r  
System.err.println(sMsg); 5[.Dlpa'7  
} F-?K]t#  
} iUl5yq  
$Hcp.J[O  
8W$uw~|dw  
/* tMxa:h;/x  
**TestMethod.java vT)(#0>z  
*/ 3n;UXYJ%  
package NetFox; hj@< wU  
gs)wQgJ[  
!|hxr#q=4  
public class TestMethod { t\ J5np  
QiB ^U^f  
&kKopJH  
public TestMethod() 6 /^$SWd2  
{ ///xx/weblogic60b2_win.exe iaAVGgA9+  
try{ gUf-1#g4\`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^vXMX^*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }gQ FWT  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Xx_ v>Jn!  
fileFetch.start(); Y! e  
} 0|<ER3xkx  
catch(Exception e){e.printStackTrace ();} vzl+0"  
tu}AJ  
Ws"eF0,'Z  
}  gBQK  
=e'b*KTL,  
GxWA=Xp^~G  
public static void main(String[] args) W]kh?+SZ  
{ Pt~mpRl H  
new TestMethod(); r`5[6)+P  
} +L_!$"I  
} %?K1X^52d  
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