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http断点续传简单实现(java)

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/* xsypIbN  
**SiteFileFetch.java 5=;I|l,  
*/ & ;x1Rx  
package NetFox; &|,qsDK(  
import java.io.*; OEqe^``!  
import java.net.*; 4~J1pcBno%  
/$N#_Xblr  
k?*DBXJv  
public class SiteFileFetch extends Thread { =u1w\>(2Y  
,)\5O0 D6  
`oI/;&  
SiteInfoBean siteInfoBean = null; //文件信息Bean x'PjP1  
long[] nStartPos; //开始位置 'jO-e^qT  
long[] nEndPos; //结束位置 J}`$WL:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )^a#Xn3z  
long nFileLength; //文件长度 OCoRcrAx  
boolean bFirst = true; //是否第一次取文件 _TeRsA  
boolean bStop = false; //停止标志 iPi'5g(a   
File tmpFile; //文件下载的临时信息 %QcG^R  
DataOutputStream output; //输出到文件的输出流 DT~y^h  
\< +47+  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) pHbguoH,  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3lEU$)QA3  
{ x)Om[jZE  
siteInfoBean = bean; ,'0oj$~S:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); N`^W*>XB  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); KPvYq?F>4  
if(tmpFile.exists ()) V$]a&wM<5  
{ V?pO~q o  
bFirst = false; HK4`@jYQ  
read_nPos(); C=f(NpyD6  
} NNrZb?  
else wUPywV1UO  
{ WYd,tGz  
nStartPos = new long[bean.getNSplitter()]; W}i$f -K  
nEndPos = new long[bean.getNSplitter()]; MrjB[3Td  
} %^BOYvPx  
WX$^[^=HC  
544I#!  
(N>ew)Ke  
} CX2q7azG  
a[9OtZX<  
uS10P7N}  
public void run() 9>Z#o<*_/  
{ iPL'JVPZ  
//获得文件长度 K%#C+`Ij  
//分割文件 &wC.?w$  
//实例FileSplitterFetch %LaC$w_X  
//启动FileSplitterFetch线程 N= q29JU  
//等待子线程返回 a5+v)F/=  
try{ [t\Mu}b  
if(bFirst) 3cQmxp2*  
{ EJ|ZZYke!  
nFileLength = getFileSize(); !ZcA Ltq  
if(nFileLength == -1) Ji?UG@  
{ 4o8HEq!  
System.err.println("File Length is not known!"); Sgk{NM7|k  
} %R5MAs&-5  
else if(nFileLength == -2) CU M~*  
{ DY27'`n6  
System.err.println("File is not access!"); uy%PTi+A  
} -5B([jHgR  
else F4l6PGxF&\  
{ QU;C*}0Zl  
for(int i=0;i<nStartPos.length;i++) K&oO+G^f  
{ {.)~4.LhQM  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); T1TZ+ \  
} ~}l,H:jk@  
for(int i=0;i<nEndPos.length-1;i++) G#M]\)f%  
{ VL1z$<vVXt  
nEndPos = nStartPos[i+1]; LOo#  
} WYUU-  
nEndPos[nEndPos.length-1] = nFileLength; /JY i^rZ  
} x1ex}_\  
} h^X.e[  
l3$?eGGM  
U?C{.@#w  
//启动子线程 fxa^SV   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; / 1GZN *I  
for(int i=0;i<nStartPos.length;i++) a{6|[a R  
{ AFA*_9Ut  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aM1JG$+7G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), U7'oI;C$e  
nStartPos,nEndPos,i); wB GxJ\+M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u _^=]K;  
fileSplitterFetch.start(); bhT]zsBK  
} 9~ af\G  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {u][q &n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); id9T[^h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", I[Y?f8gJ  
nEndPos = " + nFileLength); ? +!?$h  
// fileSplitterFetch[nPos.length-1].start(); &^>r<~]  
sbIhg/:ok  
ZU6a   
//等待子线程结束 4<HJD&@V  
//int count = 0; MM7gMAA.mz  
//是否结束while循环 o8"xoXK5xf  
boolean breakWhile = false; )&-+:u0  
3xY]Lqwv  
<C xet~x  
while(!bStop) W%:zvqg v  
{ zYJxoC{  
write_nPos(); '^AXUb  
Utility.sleep(500); o%7yhCY  
breakWhile = true; ?2Dz1#%D  
a-=apD1RvG  
w+D5a VJ  
for(int i=0;i<nStartPos.length;i++) 9)X<}*(qo  
{ 4\RuJx  
if(!fileSplitterFetch.bDownOver) )QT+;P.  
{ ddxv.kIj.  
breakWhile = false; S?<Qa;  
break; l"#,O$x"#@  
} &*-2k-16  
} 6dlPS{H#U  
if(breakWhile) 1j(,VW  
break; =jh:0Q<43+  
zt6ep=  
K.Ir+SB  
//count++; 548BM^^"r  
//if(count>4) _FgeE`X  
// siteStop(); !ZdUW]  
} .? / J  
Rl8-a8j$f.  
~VKXL,.  
System.err.println("文件下载结束!"); Q0q$ZK6C  
} VVOt%d  
catch(Exception e){e.printStackTrace ();} 9NAlgET  
} sq$|Pad[  
XjNu|H/  
$x*GvI1D  
//获得文件长度 >kT~X ,o  
public long getFileSize() c i>=45@J  
{ >Fh@:M7z  
int nFileLength = -1; '@P[fSQ  
try{ r G6/h'!|  
URL url = new URL(siteInfoBean.getSSiteURL()); ~Otf "<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?HTwTi 5!)  
httpConnection.setRequestProperty("User-Agent","NetFox"); l|{<!7a  
O'(vs"eN  
95/C4q  
int responseCode=httpConnection.getResponseCode(); 8!fw Xm  
if(responseCode>=400) I 3PnyNZ  
{ :W"ITY(  
processErrorCode(responseCode); 3[4]G@  
return -2; //-2 represent access is error JZ [&:  
} I6_+3}Hm{  
I5,Fh>  
3IIlAzne;  
String sHeader; YzqhFFaj.  
 V Euv  
^8)d8?}  
for(int i=1;;i++) *k -UQLJ  
{ "-sz7}Mb  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3 a`-_<  
//Utility.log(in.readLine()); TEtZ PGFl  
sHeader=httpConnection.getHeaderFieldKey(i); K"61i:F  
if(sHeader!=null) q!4dK4`#5  
{ =*I9qjla[?  
if(sHeader.equals("Content-Length")) E;N8{Ye_  
{ < jF<_j  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); n >'}tT)U  
break; #XZ?,neY  
} \=JKeL|6[S  
} ' BpRiN  
else R0WJdW#  
break; ]3G2mY;`"%  
} t@\0$V \X  
} p5\b&~ g  
catch(IOException e){e.printStackTrace ();} Nbda P{{  
catch(Exception e){e.printStackTrace ();} p|%)uA3'/  
JT+P>\\];'  
gd*\,P  
Utility.log(nFileLength); !TcjB;q'  
+?8nY.~,'  
o,L!F`W  
return nFileLength; Kfh"XpWc$  
} 6 S8#[b  
Y`wi=(  
WG,{:|!E  
//保存下载信息(文件指针位置) IaB A2  
private void write_nPos() #X+)  
{ YL]x>7T~4t  
try{ /D12N'VaE  
output = new DataOutputStream(new FileOutputStream(tmpFile)); VCIG+Gz  
output.writeInt(nStartPos.length); DIY WFVh  
for(int i=0;i<nStartPos.length;i++) s$Mj4_p3l  
{ YAO0>T<F  
// output.writeLong(nPos); 97lwPjq  
output.writeLong(fileSplitterFetch.nStartPos); :3k(=^%G!  
output.writeLong(fileSplitterFetch.nEndPos); JW$#~"@r  
} `WVQp"m  
output.close(); )9$Xfq/  
} AbB%osz}Ed  
catch(IOException e){e.printStackTrace ();} >.A{=?   
catch(Exception e){e.printStackTrace ();} +.=a R<Q  
} kciH  
F n\)*; ^  
y(HR1v Q;Z  
//读取保存的下载信息(文件指针位置) q(C+D%xB  
private void read_nPos() %}@^[E)  
{ &\A$Rj)  
try{ j JW0a\0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); x|Dj   
int nCount = input.readInt(); S}>rsg!  
nStartPos = new long[nCount]; IzG7!K  
nEndPos = new long[nCount]; i<l)To-  
for(int i=0;i<nStartPos.length;i++) g$ h!:wW  
{ J;qHw[6  
nStartPos = input.readLong(); _.j KcDf  
nEndPos = input.readLong(); u+*CpKR}  
} )gE:@ 3  
input.close(); 5i0<BZDTef  
} bAgKOfT  
catch(IOException e){e.printStackTrace ();} q o'1Pknz  
catch(Exception e){e.printStackTrace ();} GYBM]mW^ W  
} fQ<V_loP.@  
[bAv|;  
7w9) ^  
private void processErrorCode(int nErrorCode) b3Do{1BV  
{ E 0YXgQa  
System.err.println("Error Code : " + nErrorCode);  l)?c3  
} ]5^u^  
"ey~w=B$M  
`H\^#Zu  
//停止文件下载 rHMsA|xz6  
public void siteStop() t{$t3>p-t  
{ VB Ce=<  
bStop = true; yCwQ0|  
for(int i=0;i<nStartPos.length;i++) | #,b1|af  
fileSplitterFetch.splitterStop(); 18Ty )7r'  
$ _ gMJ\{  
$]O\Ryf6  
} :g Ze>  
} &.d~ M1Mz  
//负责部分文件的抓取 aFLm,  
**FileSplitterFetch.java JV@>dK8  
*/ ce@(Ct  
package NetFox; -IPc;`<  
il*bsnwpZv  
9khD7v   
import java.io.*; sx6` g;  
import java.net.*; *p VKMmU  
I` /'\cU9  
~(}zp<e|  
public class FileSplitterFetch extends Thread { +_+}^Nf]Y3  
R!:1{1  
x ha!.&DO  
String sURL; //File URL .*8.{n5   
long nStartPos; //File Snippet Start Position na<g /&  
long nEndPos; //File Snippet End Position 8G9V8hS1#B  
int nThreadID; //Thread's ID BH=vI<D  
boolean bDownOver = false; //Downing is over eI- ~ +.  
boolean bStop = false; //Stop identical $L?stgU  
FileAccessI fileAccessI = null; //File Access interface &DgIykqN  
Y1+f(Q  
WO]dWO6Mm  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException m~# O ~)  
{ zp d4uto5  
this.sURL = sURL; A\WgtM  
this.nStartPos = nStart; %6 Bt%H  
this.nEndPos = nEnd; U:ZklDW  
nThreadID = id; qV5ME #TJ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ZYg="q0x&  
} -B R&b2  
Ucv-}oa-?  
HZR~r:_ i  
public void run() ns@b0'IF]  
{ "",V\m  
while(nStartPos < nEndPos && !bStop) 8He^j5  
{ "Y4 tt0I  
*2@Ne[dYEF  
R:=i/P/  
try{ X)`? P*[  
URL url = new URL(sURL); nsYS0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V+_L9  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;[&g`%-H<  
String sProperty = "bytes="+nStartPos+"-"; w<5w?nP+Oh  
httpConnection.setRequestProperty("RANGE",sProperty); 7|\[ipVX:3  
Utility.log(sProperty); U1dz:OG>  
BH\qm (X  
aiea& aJ  
InputStream input = httpConnection.getInputStream(); Z?X ^7<  
//logResponseHead(httpConnection); -]HO8}-Rjs  
!<@Zf4m  
)t0t*xu#  
byte[] b = new byte[1024]; IeE+h-3p  
int nRead; eo"6 \3z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0/;T\9  
{ +\SbrB P  
nStartPos += fileAccessI.write(b,0,nRead); "h\{PoG  
//if(nThreadID == 1) DqbN=[!X~n  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W%) foJ  
} R|Y)ow51  
yjc:+Y{5'  
^qGH77#z  
Utility.log("Thread " + nThreadID + " is over!"); cvi+AZ=  
bDownOver = true; C^]bXIb  
//nPos = fileAccessI.write (b,0,nRead); ,Epg&)wC]  
} mq >Ag  
catch(Exception e){e.printStackTrace ();} s+9q :  
} @:X~^K.  
} %=%jy  
KR#Bj?fz-H  
[p|-G*=00  
//打印回应的头信息 Q l ql(*  
public void logResponseHead(HttpURLConnection con) $GPenQ~},  
{ -fn["R]  
for(int i=1;;i++) :U^a0s%B  
{ 4>gk XfTF  
String header=con.getHeaderFieldKey(i); XV]`?  
if(header!=null) %.[t(F  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |{<g-)  
Utility.log(header+" : "+con.getHeaderField(header)); q#F;GD  
else %mg |kb6n  
break; =D<46T=(RB  
} 1vu=2|QN  
} UPA))Iv>  
hI]KT a  
=k'3rm*ld  
public void splitterStop() aV,>y"S  
{ c"v#d9  
bStop = true; >?'cZTNk]  
} ~"iCx+pr  
(F +if  
% =br-c  
} &CG3_s<2  
\ @3i=!  
+kmPQdO;*/  
/* x/R|i%u-s  
**FileAccess.java +(QGlRd  
*//文件访问(定位,写) -%NT)o  
package NetFox; ma?$@ ]`k  
import java.io.*; r. =_=V/t  
U_y)p Cd  
:;#Kg_bz  
public class FileAccessI implements Serializable{ L00,{g6wqb  
$*{PUj  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o *S"`_   
RandomAccessFile oSavedFile; 1B}6 zJ  
long nPos; |r$Vb$z  
@I_A\ U{  
J#!:Z8b  
public FileAccessI() throws IOException eOE7A'X   
{ P BpjE}[Q  
this("",0); ?x%HQ2`  
} 1.]#FJe  
R4%!W~K  
&1 {RuV&t  
public FileAccessI(String sName,long nPos) throws IOException !Z`~=n3bk  
{ gQCkoQi:j  
oSavedFile = new RandomAccessFile(sName,"rw"); ZjF$zVk  
this.nPos = nPos; +MIDq{B  
oSavedFile.seek(nPos); 3W5|Y@0  
} 0bVtku K;G  
FDkRfhK  
nxA Y]Q  
public synchronized int write(byte[] b,int nStart,int nLen) 1.4]T, `  
{ b,cA mZ  
int n = -1; 'RC(ss1G  
try{ =;9Wh!{  
oSavedFile.write(b,nStart,nLen); Y7zg  
n = nLen; s0~a5Ti3  
} 2kp.Ljt@  
catch(IOException e) kVCS FF*  
{ |[)t4A"}  
e.printStackTrace (); =hH>]$J[  
} k9vr6We'  
 I QS|  
lc,{0$ 1<  
return n; ={o>g '  
} !vHnMY~AG  
<=l!~~%  
qH: ` O%,  
} snK$? 9vh  
Zm >Q-7r9  
4/&Us  
/* ><mZOTn e;  
**SiteInfoBean.java A|,\}9)4X[  
*/ ce0TQ  
package NetFox; nw+L _b  
$6L gaz  
|CexP^;!U  
public class SiteInfoBean { 47ppyh6@  
0m(/hK  
rUvqAfE&+  
private String sSiteURL; //Site's URL Xp[[ xV|  
private String sFilePath; //Saved File's Path I3uaEv7OZc  
private String sFileName; //Saved File's Name gLa# y  
private int nSplitter; //Count of Splited Downloading File d+[yW7%J  
Cg?D<l4  
#'^!@+)  
public SiteInfoBean() tV<}!~0,*  
{//nSplitter的缺省值为5 KwndY,QD  
//default value of nSplitter is 5 m"t\@f  
this("","","",5); ^/47 *vcN5  
} Ek~Qp9B  
2asA]sY  
>pW8K[  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Am'5|  
{ EDcR:Dw3  
sSiteURL= sURL; AyB-+oTf(  
sFilePath = sPath; /pan{.< k  
sFileName = sName; 8p,q9Ey  
this.nSplitter = nSpiltter; BNw^ _j1  
16_HO%v->  
T;XEU%:LK  
} @s}I_@  
OB)Vk  
S7N3L."  
public String getSSiteURL() ,%w_E[2  
{ @Ck6s  
return sSiteURL; wj!p6D;;S  
} #O6SEK|Z  
@>,3l;\Zh  
qL091P\F  
public void setSSiteURL(String value) {+r pMUs#  
{ rk*Igqf  
sSiteURL = value; Q#wASd.  
} yH#zyO4fD-  
uc<XdFcu  
 VT96ph  
public String getSFilePath() ;{ u{F L  
{ QU|{(c  
return sFilePath; FY)vrM*yh  
} w|pk1~c(_  
PX65Z|~>_  
m(,vym t  
public void setSFilePath(String value) "aHY]E{  
{ nud,ag  
sFilePath = value; PwU}<Hrl]  
} zNofI$U  
Z#BwJHh  
H=?v$! i  
public String getSFileName() 0 60<wjX6  
{ l~!Tnp\M  
return sFileName; &Y%Kr`.h  
} "%dWBvuO  
\j !JRD+j  
%Rj:r!XB:  
public void setSFileName(String value) SL" ;\[uI  
{ { :xINQ=}D  
sFileName = value; *M\Qt_[  
} U>7"BpC  
hSSF]  
0kS[`a(}J  
public int getNSplitter() M;OY+ |uA  
{ Vh$~]>t:f  
return nSplitter; :BKY#uH~  
} +8Yt91   
:P #   
-BfZ P5  
public void setNSplitter(int nCount) 3Wxl7"!x m  
{ b)9bYkd  
nSplitter = nCount; wUHuykF  
}  Z+`mla  
} S!A)kK+  
Zy,U'Dv  
A\ds0dUE  
/* !;.i#c_u  
**Utility.java } R!-*Wk  
*/ 8fFURk  
package NetFox; 9_V'P]@  
..V6U"/  
]Cnj=\'  
public class Utility { #x$.  
o)F^0t  
*X+T>SKL  
public Utility() SoeL_#+^W  
{ wr,X@y%(!  
i`Fg kABw  
4N& VT"  
} |(N4ZmTm  
dDbPM9]5  
//线程睡眠 vT"T*FKh:  
public static void sleep(int nSecond) oRFHq>-.g  
{ |VbF&*v`  
try{ rD<G_%hP  
Thread.sleep(nSecond); N(q%|h<Z/=  
} <\!+J\YTA  
catch(Exception e) J7W]Str  
{ +C1/02ZJ  
e.printStackTrace (); eyBLgJt8P  
} pqFgi_2m  
} h~{TCK+I  
sCU<1=   
//日志 z1wy@1o'  
public static void log(String sMsg) 3$[!BPLFO  
{ :"7V,UP @  
System.err.println(sMsg); 9i GUE  
} ^d Fdw\  
ag^EH"%zw  
r7o63]  
public static void log(int sMsg) |_/q0#"  
{ y3 @R>@$  
System.err.println(sMsg); M@EML @~  
} \&ra&3o  
} hE0 p> R8  
XBe!9/'k>  
W}#eQ|oCV  
/* }D/0&<1  
**TestMethod.java ++D-,>.  
*/ K.4t*-<`[  
package NetFox; JYA$_T  
RhIRCN9  
?ORG<11a  
public class TestMethod { dPgN*Bdv  
Jj4!O3\I  
+#7 e?B  
public TestMethod() 3<sYxA\?w  
{ ///xx/weblogic60b2_win.exe pE<dK.v6  
try{ pe$" nUy|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \)'s6>58|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ts/ rV#s~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); F B-?{78~  
fileFetch.start(); jPU:&1(_ n  
} $ ,Y\  
catch(Exception e){e.printStackTrace ();} !4TMgM  
&QFg=  
bzD <6Z  
} hi4#8W  
DjUif "v  
oe`t ? (U  
public static void main(String[] args) 2iC7c6hc  
{ k44s V.G4L  
new TestMethod(); L;$Gn"7~  
} xR `4<  
} ^[6eo8Ck>  
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