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http断点续传简单实现(java)

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/* ;b_<5S  
**SiteFileFetch.java u(`7F(R  
*/ ]Rmu +N|  
package NetFox; X{h[    
import java.io.*; qJXf c||Zg  
import java.net.*; +]Z *_?j9{  
;Z,l};b  
ya;(D 8x)  
public class SiteFileFetch extends Thread { v6T<K)S  
W:2]d  
dmMrZ1u2  
SiteInfoBean siteInfoBean = null; //文件信息Bean f>?b2a2HX  
long[] nStartPos; //开始位置 ^4{{ +G)j  
long[] nEndPos; //结束位置 OoZv\"}!_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 eHyIFoaC/  
long nFileLength; //文件长度 \@6V{y'Zo  
boolean bFirst = true; //是否第一次取文件 C{V,=Fo^  
boolean bStop = false; //停止标志 pWb8X}M  
File tmpFile; //文件下载的临时信息 }7qboUGe  
DataOutputStream output; //输出到文件的输出流 \F7NuG:m,  
W:2j.K9!  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) H.[(`wi!I  
public SiteFileFetch(SiteInfoBean bean) throws IOException pJQ_G`E  
{ df$pT?o  
siteInfoBean = bean; \T;(k?28HN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :&s8G*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]TsmWob  
if(tmpFile.exists ()) `O?j -zR  
{ W{kTM4  
bFirst = false; c>#3{}X|x%  
read_nPos(); 1EliR uJ  
} >V&GL{  
else <?!%dV{z  
{ z,SNJIsx  
nStartPos = new long[bean.getNSplitter()]; IXR%IggJA  
nEndPos = new long[bean.getNSplitter()]; jZq CM{  
} \YH*x`  
}y%mG&KSz  
XBTjb  
P0-K/_g  
} \Iz-<:gA'  
F=;nWQ&  
_P=L| U#C  
public void run() QU@CPME  
{ NcIr; }  
//获得文件长度 k,r}X:<6jz  
//分割文件 ZgxpHo  
//实例FileSplitterFetch HB}iT1.`  
//启动FileSplitterFetch线程 )79F"ltz h  
//等待子线程返回 "u"?~  
try{ tLGNYW!K  
if(bFirst) YA8ZB&]En/  
{ Qmj%otSg  
nFileLength = getFileSize();  '5P:;zw  
if(nFileLength == -1) +Ui%}^ZZ  
{ Mbtk:GuY  
System.err.println("File Length is not known!"); ~fz9PoC  
} m =MM  
else if(nFileLength == -2) z*/}rk4i  
{ f5#VU7=1F2  
System.err.println("File is not access!"); ^<Sy{KY  
} t\-;n:p-  
else [} "m4+  
{ XJ?zP=UK  
for(int i=0;i<nStartPos.length;i++) =o4McV}  
{ hDTM\>.c;s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <A] Kg  
} nD{{/_"'  
for(int i=0;i<nEndPos.length-1;i++) ]Q{MF- EKj  
{ 51!#m|  
nEndPos = nStartPos[i+1]; <+ckE 2j  
} oD%B'{Zs4  
nEndPos[nEndPos.length-1] = nFileLength; ;VgB!  
} /6#i$\ j  
} =UZm4=T  
\Jr7Hy1;  
Xm^/t#  
//启动子线程 o 0H.DeP  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; hKN/&P^  
for(int i=0;i<nStartPos.length;i++) ajD/)9S  
{ VOrBNu  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?qczMck_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |Q#CQz  
nStartPos,nEndPos,i); 6b h.5|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e|.a%,Dcy  
fileSplitterFetch.start(); +Pb@@C&  
} l gTw>r   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y r 1k\q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?4lEHef  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", bU_P@GKB  
nEndPos = " + nFileLength); Hr=?_Un"  
// fileSplitterFetch[nPos.length-1].start(); x7c#kU2A&Z  
IlMst16q5  
Qy| 6A@  
//等待子线程结束 G8OnNI  
//int count = 0; pt9fOih[  
//是否结束while循环 cu"ge]},  
boolean breakWhile = false; Wvwjj~HP2}  
jxDA+7  
vOBXAF  
while(!bStop) )<^G]ajn  
{ gqACIXR  
write_nPos(); 3qwSm <  
Utility.sleep(500); wWB^m@:4  
breakWhile = true; Xe<kdB3  
sm;\;MP*yH  
E>`gj~  
for(int i=0;i<nStartPos.length;i++) *uvE`4V^Jg  
{ ]0myoWpi3  
if(!fileSplitterFetch.bDownOver) !+ ??3-q  
{ :.W</o~\s  
breakWhile = false; 2M?L++i  
break; +ZPn[|  
} >S HW  
} hbTJXP~~?  
if(breakWhile) fBct%M 3  
break; Y j*Y*LB~  
v^(J+d_>   
)W3kBDD  
//count++; "l 1z@  
//if(count>4) =-n7/  
// siteStop(); 8POLp9>X  
} ,\0>d}eh !  
F;)qM|7  
bODyJ7=[  
System.err.println("文件下载结束!"); zirnur1  
} #^bn~  
catch(Exception e){e.printStackTrace ();} 2p8}6y:}7  
} O ftjm X_  
8DZ OPA  
h>&t``<  
//获得文件长度 "AHuq%j  
public long getFileSize() 'Rw*WK  
{ ? -`8w _3  
int nFileLength = -1; y_f^ dIK*=  
try{ m7m)BX%O  
URL url = new URL(siteInfoBean.getSSiteURL()); p"=8{LrO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .oxeo 0@~  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9l:vVp7Uk  
TDHS/"MbA7  
hZeF? G)L'  
int responseCode=httpConnection.getResponseCode(); 4F?O5&329i  
if(responseCode>=400) 6yXMre)YV  
{ Mg=R**s1x%  
processErrorCode(responseCode); GQ= Pkko  
return -2; //-2 represent access is error 8Z(\iZ5Rgj  
} ~`o%Y"p%rv  
uZ(,7>0  
eLN[`hJ  
String sHeader; E#mpj~{-  
%vjfAdC  
A7sva@}W  
for(int i=1;;i++) xX2/uxi8  
{ F}=O Mo:.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); s, ;L6nX"  
//Utility.log(in.readLine()); WEk3 4crk  
sHeader=httpConnection.getHeaderFieldKey(i); R(<_p"9(  
if(sHeader!=null) 6gJc?+  
{ gL6.,4q+1  
if(sHeader.equals("Content-Length")) !eGUiE=  
{ Ihg1%.^V\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .*g^ i`  
break; *|&&3&7  
} .Sjg  
} WO"<s{v  
else V?o%0V  
break; h9WyQl7  
} L$ ZZ]?7j  
} %2EHYBQjN  
catch(IOException e){e.printStackTrace ();} LFPYnK  
catch(Exception e){e.printStackTrace ();} 1agI/R  
t Ai?Bjo  
jin XK  
Utility.log(nFileLength); .+dego:  
u4.2u}A/R%  
}R2afTn[;  
return nFileLength; H(F9&6}  
} &=hkB9 ;  
uw9w{3]0f  
<l"rnM%  
//保存下载信息(文件指针位置) $z'_Hr'  
private void write_nPos() :, Ad1(  
{ L|K^w *\C  
try{ 9:]|TIPi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _$BH.I  
output.writeInt(nStartPos.length); E j/P:nB  
for(int i=0;i<nStartPos.length;i++) "c0Nv8_G  
{ ]{PJ  
// output.writeLong(nPos); H5?H{  
output.writeLong(fileSplitterFetch.nStartPos); \:`-"Ou(*  
output.writeLong(fileSplitterFetch.nEndPos); x]<0Kq9K  
} L<H6AzR+  
output.close(); EGJrnz8  
} I<LIw8LI  
catch(IOException e){e.printStackTrace ();} $%0A#&DVh  
catch(Exception e){e.printStackTrace ();} <+)B8I^  
} DYaOlT(rE  
|n+ ` t?L^  
$JZ}=\n7  
//读取保存的下载信息(文件指针位置) !t+eJj  
private void read_nPos() RL~]mI!U  
{ 6SN$El 0|G  
try{ :dj=kuUTbu  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); gtw?u b  
int nCount = input.readInt(); e? n8S  
nStartPos = new long[nCount]; &<oDl _^  
nEndPos = new long[nCount]; #i0f}&  
for(int i=0;i<nStartPos.length;i++) a&s&6Q|Y  
{ Q!v]njCIB7  
nStartPos = input.readLong(); Xe>   
nEndPos = input.readLong(); EK<ly"S.  
} _/)HAw?k  
input.close();  _V_GdQ  
} F@u>5e^6  
catch(IOException e){e.printStackTrace ();} }@Ou]o  
catch(Exception e){e.printStackTrace ();} <CY<-H  
} Nkg^;-CV0  
z2cd1HxN  
?emYLw  
private void processErrorCode(int nErrorCode) Y5$VWUrB  
{ cHk ?$  
System.err.println("Error Code : " + nErrorCode); c$52b4=a  
} 40R7@Vaf  
71!'k>]h  
7) 37AKw  
//停止文件下载 S7 WT`2  
public void siteStop() $J)2E g  
{ O>kM2xw  
bStop = true; x|q|> dPB  
for(int i=0;i<nStartPos.length;i++) T~b6Zu6  
fileSplitterFetch.splitterStop(); ~k780  
%P`w"H,v3#  
|&0zAP"\  
} =%oQIx  
} T@\%h8@~]  
//负责部分文件的抓取 I18<brZJ  
**FileSplitterFetch.java 9Jj:d)E>o  
*/ i!dQ Sdf  
package NetFox; ".Sa[A;~  
1]]#HTwX  
m. "T3K  
import java.io.*; El4SL'E@  
import java.net.*; i.G"21M  
!+Us)'L  
U((mOm6  
public class FileSplitterFetch extends Thread { I2^ Eo5'  
*ci%c^}V  
dtd}P~  
String sURL; //File URL 5;Q9Z1 `  
long nStartPos; //File Snippet Start Position (|U|>@  
long nEndPos; //File Snippet End Position |tqYRWn0  
int nThreadID; //Thread's ID  dPCn6  
boolean bDownOver = false; //Downing is over bbxo!K m"  
boolean bStop = false; //Stop identical J\c\Ar :  
FileAccessI fileAccessI = null; //File Access interface 2!;U.+(  
Ki(  
l"app]uVZ  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException SQJ }$#=  
{ k~HS_b*]d  
this.sURL = sURL; gtlyQ _V  
this.nStartPos = nStart;  - j_  
this.nEndPos = nEnd; 7o4B1YD  
nThreadID = id; pA?2UZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w~l%xiC  
} @]xH t&j  
drK &  
@'fWS^ ;&  
public void run() MZK%IC>  
{ _W^{,*p  
while(nStartPos < nEndPos && !bStop) 0;avWa)Q  
{ 8KyF0r?  
5;_&C=[  
{&d )O  
try{ `;\~$^sj}  
URL url = new URL(sURL); ]0@ 06G(y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lz88//@gZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); fs;pX/:FR  
String sProperty = "bytes="+nStartPos+"-"; 4NxI:d$&*  
httpConnection.setRequestProperty("RANGE",sProperty); a<d$P*I(cH  
Utility.log(sProperty); n06Jg+  
To@77.'  
6BIr{SY  
InputStream input = httpConnection.getInputStream(); =%ZR0cWPoI  
//logResponseHead(httpConnection); 9G=HG={  
D;QV`Z% I  
v!77dj 6I  
byte[] b = new byte[1024]; 85 <%L:EC  
int nRead; MMS#Ci=Lj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) | +r5D4]e  
{ [&h%T;!Qii  
nStartPos += fileAccessI.write(b,0,nRead); g&`[r6B  
//if(nThreadID == 1) :elTqw>pn  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kQQhZ8Ch  
} /Vy,6:$H3  
0FG|s#Ig  
Fooa~C"  
Utility.log("Thread " + nThreadID + " is over!"); h(MS>=  
bDownOver = true; v7@O ,%  
//nPos = fileAccessI.write (b,0,nRead); @1^:V-=  
} IM$I=5y e  
catch(Exception e){e.printStackTrace ();} C3GI?| b  
} }j6<S-s~  
} )*T <s  
d6ABgQi0  
Jl|^  
//打印回应的头信息 2E_*'RT  
public void logResponseHead(HttpURLConnection con) DX#_0-o  
{ G;Thz  
for(int i=1;;i++) >C"QV `+  
{ /{HK0fd  
String header=con.getHeaderFieldKey(i); > J>|+W  
if(header!=null) F|{F'UXj|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1H]E:Bq  
Utility.log(header+" : "+con.getHeaderField(header)); B#Z-kFn@  
else ]n$&|@  
break; 9_I#{ ?  
} QLum=YB  
} ![CF >:e  
! tPHT  
o dTg.m  
public void splitterStop() gt{$G|bi  
{ ``* !b >)  
bStop = true; -e(,>9Q  
} 6> Ca O  
o; N s-=  
StWF66u34&  
} 6kM'f}t[C  
;gmfWHB<  
y_A?} 'X  
/* c3G&)gU4q  
**FileAccess.java ?2$0aq  
*//文件访问(定位,写) j~VHU89  
package NetFox; `.F+T)G  
import java.io.*; SdOE^_@:  
U)y~{E~c34  
#RWHk  
public class FileAccessI implements Serializable{ rm nfyn  
z(dX<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Zk#?.z}  
RandomAccessFile oSavedFile; >HlQ+bl$xw  
long nPos; ;?'=*+'>  
oYNp0Hc  
$dgez#TPL  
public FileAccessI() throws IOException j~:N8(=  
{ lM'yj}:~  
this("",0); RFzMah?Q=j  
} H G)c\b  
$,L,VYN  
JU\wvP5j  
public FileAccessI(String sName,long nPos) throws IOException V|mz]H#|  
{ .7Lv  
oSavedFile = new RandomAccessFile(sName,"rw"); n`af2I2  
this.nPos = nPos; gdVajOAu  
oSavedFile.seek(nPos); GtNGrJU  
} cgvD>VUw  
6q]`??g.  
KIfR4,=Q|  
public synchronized int write(byte[] b,int nStart,int nLen) [H8QxJk  
{ I}{Xv#@o  
int n = -1; p-1 \4  
try{ #w:6<$  
oSavedFile.write(b,nStart,nLen); [d~ 25  
n = nLen;  T24?1  
} J4;F k  
catch(IOException e) #m<<]L(o8W  
{ (!9ybH;T  
e.printStackTrace (); 0;pOQF  
} z`Cq,Sz/  
B{+ Ra  
{f }4l  
return n; en6oFPG   
} <dA1n:3o  
7 /$s!pV  
A"8"e*  
} b!ea(D!:  
6bW:&IPQ;  
r=3knCEWK  
/* @JL+xfz  
**SiteInfoBean.java Q4JvFy0'  
*/ &^W91C?<6  
package NetFox; {Z=m5Dy}  
Cw_XLMY%V1  
(~<9\ZJs  
public class SiteInfoBean { / NlT[@T  
aj:B+}1  
&@MiR8  
private String sSiteURL; //Site's URL c#6g[TE@  
private String sFilePath; //Saved File's Path *1 [v08?!  
private String sFileName; //Saved File's Name G$"$k=[  
private int nSplitter; //Count of Splited Downloading File '!6Py1i  
L)LW5%.6  
CrIt h/Z  
public SiteInfoBean() 'l}T_7g  
{//nSplitter的缺省值为5 \|}dlG  
//default value of nSplitter is 5  `=h`:`  
this("","","",5); _@47h86 Q  
} $"/xi `  
3+E AMn  
bf3Njma%  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) UHEn+Tc>  
{ r6Hdp  
sSiteURL= sURL; S^Z[w|1  
sFilePath = sPath; %EooGHGF?  
sFileName = sName; ~KufSt *  
this.nSplitter = nSpiltter; .#] V5g,  
R""P01IZH  
V~uH)IMkh7  
} ]$>O--  
i: ZL0nH-  
jB17]OCN  
public String getSSiteURL() H -sJt:  
{ %dMP}k/  
return sSiteURL; #iOoi9(  
} BF_R8H,<%  
RG)!v6  
-H3tBEvoI  
public void setSSiteURL(String value) (,gpR4O[  
{ >*PZ&"}M  
sSiteURL = value; \+cU}  
} x)SW1U3TVx  
G Uf[Dz  
(1pxQ%yEA  
public String getSFilePath() UtF8T6PKdW  
{ 7X$[E*kd  
return sFilePath; @k!J}O K  
} oT4A|M  
fq.ui3lP)  
4X@ <PX5  
public void setSFilePath(String value) 0z2A!ap  
{ p. eq N  
sFilePath = value; Y?(kE` R  
} K{}U[@_tS  
hy"O_Le  
ER O'{nT&  
public String getSFileName() swBgV,;   
{ :3s5{s   
return sFileName; cViEvS r  
} Vs-])Q?7J  
3Ms ` ajJ  
+ou ]|  
public void setSFileName(String value) xm }9(EJ  
{ b3G4cO;t;  
sFileName = value; (3DjFT3 w  
} Lbka*@  
I6x  
HWJ(O/N  
public int getNSplitter() lw4#xH-?  
{ hlpi-oW`  
return nSplitter; iyF~:[8  
} mTcopyp  
bqHR~4 #IR  
2g elmQnc  
public void setNSplitter(int nCount) FC:Z9{2!  
{ |0A"3w  
nSplitter = nCount; G[}$s7@k  
} +rw?k/  
} HJVi:;o  
[*<F   
_;G. QwHr  
/* 2NHkK_B1P  
**Utility.java M^c`j#NQ  
*/ U{vt9t  
package NetFox; g]IRv(gDh  
la7VeFT  
}Fd4; ]  
public class Utility { tiZ5 :^$b4  
I%]~]a  
jN\} l|;q  
public Utility() /DG+8u  
{ >hkmL](^  
qB57w:J  
ra L!}  
} =.=4P~T&  
V _(L/6  
//线程睡眠 WoVPp*zlX  
public static void sleep(int nSecond) M ABrf`<b  
{ eI8rnp( Ia  
try{ DQ '=$z  
Thread.sleep(nSecond); '- >%b  
} _g|zDi^  
catch(Exception e) WaY_{)x  
{ yrp5\k*{y  
e.printStackTrace (); hk =nXv2M  
} D# ZzhHHP  
} ;GW[Yw>Rz  
i6L>,^Dg  
//日志 `nAR/Ye  
public static void log(String sMsg) ;JM%O8  
{ b&AGVWhh  
System.err.println(sMsg);  `mar-r_m  
} <L4.*  
^I=W<  
;D}8acQ  
public static void log(int sMsg) {MP8B'r-6  
{ lSGtbSyDI  
System.err.println(sMsg); toD v~v  
} 3uSj5+@q6  
} td*1  
i3bH^WwE&k  
?b?6/_W~R  
/* ({XB,Rm  
**TestMethod.java h<)YZ[;x  
*/ PtH>I,/  
package NetFox; f{ ;L"*L  
,$"*X-1  
=Q\z*.5j.  
public class TestMethod { Rra3)i`*  
%49P<vo`?  
%w+"MkH _  
public TestMethod() c/:d$o-  
{ ///xx/weblogic60b2_win.exe ;DQ{6(  
try{ W7bA#p(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); n}KF) W=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &I8Q'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :<t%Sf  
fileFetch.start(); RO>3U2  
} uY{zZ4iw  
catch(Exception e){e.printStackTrace ();} }BTK+Tk8  
0;Lt  
,8=`Y9#  
} /WvF}y  
m=g\@&N  
1(S0hm[ov  
public static void main(String[] args) iLQFce7d|&  
{ L#t^:%   
new TestMethod(); 0:NCIsIm<  
} RKIBFP8.  
} &hTe-Es  
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