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http断点续传简单实现(java)

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/* $D\l%y/C  
**SiteFileFetch.java Vd>.fb\U2  
*/ s@[t5R  
package NetFox; U7%pOpO!  
import java.io.*; 4S EC4yO  
import java.net.*; GaqG 8% .  
n)!_HNc9  
(E(:F[.S  
public class SiteFileFetch extends Thread { g E+OQWu  
J9c3d~YW  
D2 cIVx3:(  
SiteInfoBean siteInfoBean = null; //文件信息Bean q>4i0p8^  
long[] nStartPos; //开始位置 e+ w  
long[] nEndPos; //结束位置 C|@k+^S  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Z?aR9OTP  
long nFileLength; //文件长度 w*P4_= :%Y  
boolean bFirst = true; //是否第一次取文件 !!O{ ppM  
boolean bStop = false; //停止标志 %FFm[[nxI  
File tmpFile; //文件下载的临时信息 =\7p0cq&*  
DataOutputStream output; //输出到文件的输出流 }JMkM9]  
`(suRp8!  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `+;oo B  
public SiteFileFetch(SiteInfoBean bean) throws IOException zP'pfBgbJW  
{ < LAD  
siteInfoBean = bean; LVl0:!>~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); w} q@VVB%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >6834e  
if(tmpFile.exists ()) 4l UE(#kUM  
{ Zw\V}uXI?  
bFirst = false; Wc>)/y5$  
read_nPos(); 8"UG&wLT  
} IX?%H!i  
else <+,0 G`  
{ =>%%]0  
nStartPos = new long[bean.getNSplitter()]; B^Mtj5Oc  
nEndPos = new long[bean.getNSplitter()]; :!!`!*!JH  
} !TZ/PqcE  
)stWr r&  
B2WX#/lgd  
4EbiCSo  
} ^Es)?>eah  
:I(gz~u6  
)nxIxr0d-  
public void run() kzpbs?<;  
{ ts!aKx  
//获得文件长度 <qY>d,+E'  
//分割文件 EXzNehO~e  
//实例FileSplitterFetch [IA==B7  
//启动FileSplitterFetch线程 :FpBz~!a  
//等待子线程返回 L([>yQZ  
try{ =,G(1#  
if(bFirst) ;-^9j)31+F  
{ qk1D#1vl  
nFileLength = getFileSize(); 6mpUk.M"  
if(nFileLength == -1) $%8n,FJ[  
{ \9zC?Cw  
System.err.println("File Length is not known!"); yP]W\W'  
} OBQ!0NM_b  
else if(nFileLength == -2) {;M/J  
{ iPpJ`i#@+  
System.err.println("File is not access!"); t3JPxg]0k'  
} m48Y1'4  
else Vn;] ''_  
{ oHnpwU  
for(int i=0;i<nStartPos.length;i++) () ;7+  
{ I;:_25WGC  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )p9n|C  
} 7/!C  
for(int i=0;i<nEndPos.length-1;i++) SJ+-H83x  
{ ;#yz i2f  
nEndPos = nStartPos[i+1]; .cog9H'  
} 'p]qN;`'O$  
nEndPos[nEndPos.length-1] = nFileLength; 0\*<k`dY  
} %$ ?Q%  
} ]%hI-  
vUeel%  
xTm&`Xo  
//启动子线程 gg_(%.>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; x[6Bc  
for(int i=0;i<nStartPos.length;i++) v"_#.!V  
{ @sO.g_yM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z@A1+kUS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), RE$-{i  
nStartPos,nEndPos,i); |XG7UH  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kcUt!PL  
fileSplitterFetch.start(); Te#[+B?  
} b"bj|qF~E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TY?io@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ve) :I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (@ sKE  
nEndPos = " + nFileLength); n\9*B##  
// fileSplitterFetch[nPos.length-1].start(); S-|$sV^cG  
Ooy96M~_G  
6mLE-( Z7  
//等待子线程结束 <P- r)=^  
//int count = 0; K\Q 1/})  
//是否结束while循环 j,jUg}b  
boolean breakWhile = false; QNEaj\   
-.{7;6:(k  
,CF~UX% bU  
while(!bStop) 8;3FTF  
{ ^o:5B%}#[  
write_nPos(); >UH=]$0N  
Utility.sleep(500); +?tNly`  
breakWhile = true; <{kj}nxz  
J1t?Qj;f3  
j<?4N*S  
for(int i=0;i<nStartPos.length;i++) ABGL9;.8  
{ o*'3N/D~  
if(!fileSplitterFetch.bDownOver) WU_Q 7%+QS  
{ 8+F2 !IM  
breakWhile = false; 5]JXXdt  
break; DLZ63'  
} 6}2Lt[>O  
} omP 7|  
if(breakWhile) 8/v_uEG  
break; VZR6oia  
:+$_(* Z  
2c]O Mtk  
//count++; j)Gr@F>  
//if(count>4) ccAEN  
// siteStop(); "p\KePc;@  
} `0N/ /Q  
\g/E4U .+  
P6rL;_~e  
System.err.println("文件下载结束!"); S)?B  I  
} m`aUz}Y>c  
catch(Exception e){e.printStackTrace ();} p9J(,}  
} l[Oxf|  
3kg+*]tLx  
Uz_{jAhW]  
//获得文件长度 L^}kwu#  
public long getFileSize() QKxu vW  
{ #a| 5A:g%  
int nFileLength = -1; 9AaixI  
try{ **"sru;@=  
URL url = new URL(siteInfoBean.getSSiteURL()); V6N#%(?3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ww*F}}(  
httpConnection.setRequestProperty("User-Agent","NetFox"); Emo]I[<&q  
V qf}(3K0  
:T2K\@  
int responseCode=httpConnection.getResponseCode(); \)hmg  
if(responseCode>=400) Sob+l'U$  
{ 2J$Uz,@  
processErrorCode(responseCode); gnt[l0m  
return -2; //-2 represent access is error +H_Z!T.@  
} nS#;<p$\  
X8<ygci+.5  
GS@ wG  
String sHeader; +8"H%#~  
URwFNOM2  
Im =E?t  
for(int i=1;;i++) &Jz%L^  
{ m6}"g[nN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); NH/H+7,o  
//Utility.log(in.readLine()); XUWza=BR"  
sHeader=httpConnection.getHeaderFieldKey(i); @EvnV.  
if(sHeader!=null) h fNBWN  
{ nr}H;wB  
if(sHeader.equals("Content-Length")) v{+*/NQ_  
{ +%^D)   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [z?XVl<  
break; 4 Q.70  
} O<5bsKw'r  
} "[G P)nC  
else V.}U p+WL  
break; M II]sF  
} zKZ6Qjd8!  
} s_|wvOW)'  
catch(IOException e){e.printStackTrace ();} 4YJs4CB  
catch(Exception e){e.printStackTrace ();} ^H>vJT  
{k>m5L  
;X>KP,/r$  
Utility.log(nFileLength); /D~:Ufw  
&'Ch[Wo]H  
tfsG P]9$  
return nFileLength; ]yyfE7{q  
} ;tj_vmZ@R  
"dt3peH  
PGJ?=qXr#  
//保存下载信息(文件指针位置) cCwT0O#d  
private void write_nPos() w% M0Mu  
{ ?mMd6U&J  
try{ 7be?=c)+"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ) ":~`Z*@  
output.writeInt(nStartPos.length); }9'rTLM  
for(int i=0;i<nStartPos.length;i++) Jyn>:Yq(  
{ J{91 t |  
// output.writeLong(nPos); kZ2+=/DYN  
output.writeLong(fileSplitterFetch.nStartPos); eL],\\q  
output.writeLong(fileSplitterFetch.nEndPos); uE>}>6)b  
} xH0Bk<`V:  
output.close(); M@.1P<:h  
} 5D'8 l@7  
catch(IOException e){e.printStackTrace ();} A ="h}9ok  
catch(Exception e){e.printStackTrace ();} JprZ6 >  
} jtA Yp3M-$  
@0aUWG!k  
St?vd+(>  
//读取保存的下载信息(文件指针位置) ^+pmZw9 0  
private void read_nPos() mZORV3bN  
{ *`\>J.  
try{ ,30&VW##  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); y|X[NSA  
int nCount = input.readInt(); 7XZ!UC;i  
nStartPos = new long[nCount]; PR Y)hb;1  
nEndPos = new long[nCount]; Tf+B<B:  
for(int i=0;i<nStartPos.length;i++) [scPs,5Y  
{ K[sfsWQ.  
nStartPos = input.readLong(); D[<8(~VP  
nEndPos = input.readLong(); !j- 7,  
} >:s:`Au  
input.close(); xi-^_I  
} <K)^MLgN  
catch(IOException e){e.printStackTrace ();} 4bmpMF-  
catch(Exception e){e.printStackTrace ();} O,7P6  
} K,J:i^2  
~;{)S}U@R  
\wM r[_LW  
private void processErrorCode(int nErrorCode) C! :\H<gI  
{ >2_J(vm>  
System.err.println("Error Code : " + nErrorCode); TkK- r(=  
} M6?*\ 9E  
!X8:#a(  
"g0L n5&  
//停止文件下载 w+Ag!O}.L  
public void siteStop() ~6R| a  
{ |n0 )s% 8`  
bStop = true; !Y5O3^I=u  
for(int i=0;i<nStartPos.length;i++) m'Wz0b^BO  
fileSplitterFetch.splitterStop(); 8c#u"qF  
& %1XYpA.0  
&B[$l`1  
} ?QZ\KY  
} 9c<lFZb;  
//负责部分文件的抓取 z"R-Sme  
**FileSplitterFetch.java q[r|p"TGov  
*/ 5pz%DhjLo  
package NetFox; 4e9mN~  
@HR]b^2E  
S&9{kt|BI  
import java.io.*; i_V~SC`  
import java.net.*; 55fV\3F|R  
e1K,4 Bq  
8J Gt|,  
public class FileSplitterFetch extends Thread { )Nk^;[  
R}BHRmSQ  
'AHI;Z~Gk  
String sURL; //File URL qbmy~\ZY  
long nStartPos; //File Snippet Start Position C";F's)  
long nEndPos; //File Snippet End Position Qu!Lc:oM?  
int nThreadID; //Thread's ID nKch _Jb  
boolean bDownOver = false; //Downing is over :v=Yo  
boolean bStop = false; //Stop identical <kt,aMw[*  
FileAccessI fileAccessI = null; //File Access interface (eSa{C\  
Rj1Z  
F.K7w  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException m@)K]0g<f  
{ 59IxY ?  
this.sURL = sURL; J'|qFS  
this.nStartPos = nStart; 5|";L&`  
this.nEndPos = nEnd; nRJcYl~ Y  
nThreadID = id; Td}#o!4!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _yumUk-QW  
} Em-88=X O  
<S%M*j  
#"=_GA^.{  
public void run() "^yTH/m  
{ g*TAaUs|n  
while(nStartPos < nEndPos && !bStop) 6;k#|-GU&  
{ $s$z"<  
t(}\D]mj  
k?KKb /&b  
try{ #O* ytZ  
URL url = new URL(sURL); noV]+1#"V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =.f]OWehu.  
httpConnection.setRequestProperty("User-Agent","NetFox"); (@>X!]{$  
String sProperty = "bytes="+nStartPos+"-"; hU@ 9vU<U  
httpConnection.setRequestProperty("RANGE",sProperty); $xJVUV  
Utility.log(sProperty); Rcfh*"k  
yuWoz*:t  
 5k{a(I  
InputStream input = httpConnection.getInputStream(); dr'#  
//logResponseHead(httpConnection); d\+smED  
1 ^TOTY  
.|;`qU o  
byte[] b = new byte[1024]; x~rIr#o  
int nRead; ?>LsIPa  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) I#tn/\n  
{ 7g[T#B'/x,  
nStartPos += fileAccessI.write(b,0,nRead); F_$eu-y  
//if(nThreadID == 1) XOAZ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y4^6I$M7V  
} xQT`sK+  
[RTB|0Q  
615, P/  
Utility.log("Thread " + nThreadID + " is over!"); "X=l7{c/  
bDownOver = true; =0cyGo  
//nPos = fileAccessI.write (b,0,nRead); -y;SR+  
} -L}crQl.'c  
catch(Exception e){e.printStackTrace ();} 89?$xm_m  
} *+{umfZy  
} aOFF"(]Cl  
LxC*{t/>8  
E`}KVi57  
//打印回应的头信息 # XE`8$  
public void logResponseHead(HttpURLConnection con) +q[puFfl  
{ ;9MsV.n  
for(int i=1;;i++) OQIQ   
{ bsO78a~=P  
String header=con.getHeaderFieldKey(i); Ii_X^)IL(  
if(header!=null) fH-V!QYGF  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); BrcT`MM[(=  
Utility.log(header+" : "+con.getHeaderField(header)); I"eXoqh  
else rZm|7A)i  
break; h(*!s`1  
} { AdPC?R`  
} gpB3\  
Q&S\?cKe  
$y S7u  
public void splitterStop() R s_bM@  
{ `VM@-;@w  
bStop = true; R/&Bze  
} ,{!~rSq-l  
Z<T%:F  
Ke@zS9  
} #Y6'Q8g f  
#0V$KC*>  
q|xJ)[AO  
/* A6v<+`?  
**FileAccess.java O:3LA-vA  
*//文件访问(定位,写) ~OO&%\$k  
package NetFox;  [R:\  
import java.io.*; `],'fT|,S  
&>y[5#qOl  
, g\%P5  
public class FileAccessI implements Serializable{ D^V0kC p!F  
xFvDKW)_X7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 })f4`$qf  
RandomAccessFile oSavedFile; G41 gil6k  
long nPos; 0 UdAF  
R1u1  
`&]<_Jc1  
public FileAccessI() throws IOException 4 qMO@E_  
{ #/!fLU@  
this("",0); c]3% wL  
} s8 S[w   
BBnW0vAZ*  
F=)9z+l#  
public FileAccessI(String sName,long nPos) throws IOException wn2+4> |~p  
{ )bN|*Bw3  
oSavedFile = new RandomAccessFile(sName,"rw"); ~u| k1  
this.nPos = nPos; l+g\xUP  
oSavedFile.seek(nPos); 3{OY&   
} ernZfd{H  
1|/P[!u  
".aypD)W  
public synchronized int write(byte[] b,int nStart,int nLen) 1haNca_6,  
{ WrWJ!   
int n = -1; &-^|n*=g6  
try{ ]r++YIg!j  
oSavedFile.write(b,nStart,nLen); ,9jq @_  
n = nLen; 1 ?X(q  
} fT9z 4[M  
catch(IOException e) /HCd52  
{ uFxhr2 <z  
e.printStackTrace (); 1NJ,If]  
} ;:(kVdb  
2ZHeOKJ-  
t [gz#'  
return n; AL*P 2\8  
} I{>U7i 5  
N$#518  
4-l G{I_S:  
} 8w,U[aJm  
$r0~& $T&  
x\HHu]  
/* t\YN\`XD  
**SiteInfoBean.java d:KUJ Y.  
*/ .1F(-mLd  
package NetFox; Tc{r;:'G<  
UG)J4ZX  
zQY|=4NP  
public class SiteInfoBean { N~I2~f  
Q.SLiI  
#XSs.i{  
private String sSiteURL; //Site's URL 00s&<EM  
private String sFilePath; //Saved File's Path 8&?kr/_Vr  
private String sFileName; //Saved File's Name )C>4? )  
private int nSplitter; //Count of Splited Downloading File &E98&[`7  
_3_d;j#G U  
Yr9>ATR  
public SiteInfoBean() j#KL"B_ A  
{//nSplitter的缺省值为5 V?KACYd@O  
//default value of nSplitter is 5 9rhIDA(wc  
this("","","",5); w]n ,`r^  
} (#zSVtZ  
b-sbRR  
5HWVK.  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) K.A!?U=  
{ n,KOQI;  
sSiteURL= sURL; ?sF<L/P0 F  
sFilePath = sPath; Koh`|]N  
sFileName = sName; uc6;%=%+  
this.nSplitter = nSpiltter; AiUICf?{  
?Bg<74  
UzLe#3MU  
} We^! (G  
Rg/*)SKj  
o_un=ygU  
public String getSSiteURL() 1PwqW g-\\  
{ %lL^[`AR  
return sSiteURL; Bq}p]R3X  
} M,0@@:  
KEfn$\  
B?}ZAw>  
public void setSSiteURL(String value) k M/cD`  
{ x)'4u6;d  
sSiteURL = value; }=kf52Am,}  
} -49z.(@ki  
JaC =\\B  
y  @&Cn  
public String getSFilePath() rh;@|/<l  
{ u&Ze$z  
return sFilePath; !ueyVE$1  
} & w{""'  
kYxb@Zn=|  
M[wd.\ %  
public void setSFilePath(String value) &_Py{Cv@Dw  
{ e}qG_*  
sFilePath = value; [UJC/GtjS  
} fV[(s7vW  
.]_Ye.}  
+8+@Az[e0  
public String getSFileName() jR/YG ru  
{ sP1wO4M?{  
return sFileName; \ Y[  
} #&+0hS  
"tu BfA+f  
;aA,H&   
public void setSFileName(String value) ]fH U/%  
{ mmC&xZ5f  
sFileName = value; ]<z4p'F1%  
} &m=Xg(G~c  
r81YL  
$+` YP  
public int getNSplitter() r3a$n$Qw  
{ *%JncK '  
return nSplitter; S4RvWTtQV  
} }wmn v  
cr!6qv1  
@WIcH:_w-  
public void setNSplitter(int nCount) w9D<^(_}/  
{ 7.4Q  
nSplitter = nCount; w3lR8R]  
} neW_mu;~Z  
} %GUu{n<6  
!6_lD 0  
Kp") %p#  
/* (g2?&b iuz  
**Utility.java G)28#aH  
*/ I(fq4$  
package NetFox; @NMFurm  
^p#f B4z  
6 W/S?F~{  
public class Utility { ;Ab`b1B  
X E]YKJ?|k  
=PXQ X(_  
public Utility() UkrqHHpy  
{ "oZ]/(  
EL+6u>\- k  
8%s ^>.rG  
} WN9 <  
$"[1yQ<p  
//线程睡眠 z)Xf6&  
public static void sleep(int nSecond) @/}{Trmg/  
{ Dt,b\6  
try{ & f7{3BK  
Thread.sleep(nSecond); R }M'D15  
} =jvM$  
catch(Exception e) /sY(/ J E  
{ =T5vu~[J/e  
e.printStackTrace (); +}c '4hRv  
} 4,L(  
} IVD1 mk  
Q!/<=95E  
//日志 dzDh V{  
public static void log(String sMsg) I}/o`oc  
{ G v[W)+3f  
System.err.println(sMsg); 'Im7^!-d  
} ?(GMe>  
@AUx%:}0Y:  
xZjl_ b J  
public static void log(int sMsg) jR7 , b5  
{ q q}EXq^  
System.err.println(sMsg); vlCjh! x  
} a5WVDh, cR  
} DX.u"&Mm  
\dj&4u3  
lJ@2N$w  
/* CBx1.xL  
**TestMethod.java >nmby|XtW  
*/ BMU}NZA  
package NetFox; kzr9-$eb  
]k Ls2? \  
R`ajll1  
public class TestMethod { TF 6_4t6  
KquHc-fzqr  
"m +Eu|{  
public TestMethod() N8(xz-6  
{ ///xx/weblogic60b2_win.exe Nj||^k  
try{ `*e',j2}UU  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P(G$@},W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); L*bUjR,C  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fV*x2g7w  
fileFetch.start(); s]`&9{=E  
} I_.(&hMn  
catch(Exception e){e.printStackTrace ();} QQP bKok>  
BZEY^G  
I9N?zmH  
} 9Q- /Yh  
'-3AWBWI1  
]O',Ei^  
public static void main(String[] args) XyJ*>;q  
{ A/RHb^N  
new TestMethod(); <aa# OX  
} 4q[C' J  
} *#e%3N05_  
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