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http断点续传简单实现(java)

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/* QS` PpyBkd  
**SiteFileFetch.java T arIPp  
*/ 52 fA/sx  
package NetFox; Crho=RJPR  
import java.io.*; ZniB]k1  
import java.net.*;  -QM: q  
#h8Sq~0  
aB{vFTD5  
public class SiteFileFetch extends Thread { )z73-M V"  
j53*E )d  
h_:C+)13`x  
SiteInfoBean siteInfoBean = null; //文件信息Bean LcB]Xdsa(  
long[] nStartPos; //开始位置 &,c``z  
long[] nEndPos; //结束位置 } z _  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "$ Y_UJT7  
long nFileLength; //文件长度 l_P-j 96WD  
boolean bFirst = true; //是否第一次取文件 {*0<T|<n  
boolean bStop = false; //停止标志 ![YX]+jqNp  
File tmpFile; //文件下载的临时信息 Xm%D><CC8"  
DataOutputStream output; //输出到文件的输出流 C&*oI =6  
VY;{/.Sa  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) pQ=>.JU  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y;@>b{s  
{ 1zm ulj%&  
siteInfoBean = bean; Pe3@d|-,MU  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); XC0bI,Fu,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4e~A1-  
if(tmpFile.exists ()) #A1Z'y0  
{ ko.(pb@+  
bFirst = false; R?~Yp?B^  
read_nPos(); =j5MFX.-o  
} -Zf@VW,NI  
else s+,OxRVw(  
{ Zhh2v>QOy  
nStartPos = new long[bean.getNSplitter()]; ?s\:hNNY  
nEndPos = new long[bean.getNSplitter()]; M=F xB;v  
} z3&]%Q&  
P7nc7a  
h{HF8>u[  
3D!5T8 @  
} AsAT_yv#  
2XFU1 AW  
<j*;.yyC  
public void run() ^?0DP >XA  
{ PP;}e  
//获得文件长度 +BVym~*^  
//分割文件 8$85^Of  
//实例FileSplitterFetch zVXC1u9B  
//启动FileSplitterFetch线程 6x h:/j3  
//等待子线程返回 xy5lE+E_U  
try{ <tF9V Jq  
if(bFirst) J pFfzb  
{ Gn|F`F  
nFileLength = getFileSize(); M m[4yP%  
if(nFileLength == -1) s }UjGFP  
{ UDL!43K  
System.err.println("File Length is not known!"); $@^pAP   
} zEd0Tmt  
else if(nFileLength == -2) i]Fp..`v~  
{ *BR~}1 i  
System.err.println("File is not access!"); ;> _$`  
} ORyE`h  
else ohFJZ'  
{ F~%]6^$w  
for(int i=0;i<nStartPos.length;i++) //T>G_1  
{ M9V q -U18  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); rR9|6l 3  
} "uuVy$6C  
for(int i=0;i<nEndPos.length-1;i++) so"$m  
{ Izhee%c  
nEndPos = nStartPos[i+1]; _,xc[ 07  
} g!$!F>[  
nEndPos[nEndPos.length-1] = nFileLength; KM}f:_J*lg  
} qfL~Wp2E;  
} Y ;u<GOe  
4wID]bKM  
<(-= 'QA  
//启动子线程 $FlW1E j  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0vEoGgY0*:  
for(int i=0;i<nStartPos.length;i++) vy0X_DPCr  
{ p<TpK )  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?]Pmxp H}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), CN#+U,NZV  
nStartPos,nEndPos,i); qUjmB sB  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {;N,t]>8M  
fileSplitterFetch.start(); 6|aKL[%6  
} jGXO\:s O  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;i Fz?d3;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !lf|7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ap&?r`Tu  
nEndPos = " + nFileLength); 4]h =yc R  
// fileSplitterFetch[nPos.length-1].start(); $ et0s;GBv  
MaRi+3F  
zo+nq%=  
//等待子线程结束 [q/Abz'i  
//int count = 0; 2"Ecd  
//是否结束while循环 @6{~05.p  
boolean breakWhile = false; b%<9Sn   
DB-l$rj  
.q%WuQw  
while(!bStop) B8B; y^b>i  
{ 0J?~N`#O|  
write_nPos(); Y' %^NP}o  
Utility.sleep(500);  Fy`(BF\  
breakWhile = true; iz8Bf;  
A*2  bA  
[z9 `)VIe  
for(int i=0;i<nStartPos.length;i++) aa>xIW,u  
{ >#hO).`C  
if(!fileSplitterFetch.bDownOver) `8^TTQ  
{ CjlKMbnBH  
breakWhile = false; Svondc 4  
break; LXbP 2  
} 4*Q#0`um  
} ^.1c{0Y^0  
if(breakWhile) 0Uo\wyd  
break; FrTi+& <  
AWP"b?^G|  
k`0>36  
//count++; A%`[mc]4#  
//if(count>4) V'kX)$  
// siteStop(); zUKmxy@  
} p3 w  
ptDY3n~'  
NF+iza;DP  
System.err.println("文件下载结束!"); Z&|Kki*  
} n^z]q;IN2.  
catch(Exception e){e.printStackTrace ();} :?/cPg'D  
} 8-BflejX  
gW-V=LV (  
'yL%3h _@  
//获得文件长度 Ag&0wN+jTM  
public long getFileSize() H-~6Z",1  
{ QA<Jr5Ys  
int nFileLength = -1; XmEq2v  
try{ GM3f- \/  
URL url = new URL(siteInfoBean.getSSiteURL()); cm?\ -[cV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  ~ ip,Nl  
httpConnection.setRequestProperty("User-Agent","NetFox"); S-k8jm  
K{[%7AM  
'7+4`E  
int responseCode=httpConnection.getResponseCode(); nq6@6GRG  
if(responseCode>=400) QlJ)F{R8il  
{ yp$_/p O=2  
processErrorCode(responseCode); %] >KvoA  
return -2; //-2 represent access is error pgOQIzu  
} @^T1XX  
_~piZmkG$  
5\e9@1Rc  
String sHeader; "tB;^jhRs  
JKGc3j,+#  
Vm3v-=6  
for(int i=1;;i++) !Cr(P e]  
{ $4/yZaVb  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .u4 W /  
//Utility.log(in.readLine()); ig/%zA*Bo  
sHeader=httpConnection.getHeaderFieldKey(i); -?mfE+kt  
if(sHeader!=null) Z/t+8;TMR,  
{ (>r[- Bft  
if(sHeader.equals("Content-Length")) Cq%IE^g<  
{ pov)Z):}G<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); gLy&esJl1  
break; #wV8X`g  
} ](&{:>RNJ  
} O+]Ifm[  
else ;`^WGS(3.%  
break; ;~D)~=|ZZ  
} 7PtN?;rP  
} ^R# E:3e  
catch(IOException e){e.printStackTrace ();} [N/"5 [  
catch(Exception e){e.printStackTrace ();} h&--,A >  
%`r?c<P}  
N7O-2Z *  
Utility.log(nFileLength); 9D7+[`r(-  
i'#E )  
hJZV}a|  
return nFileLength; y *fDwd~  
} f}x.jxY?  
22.8PO0  
Bs O+NP  
//保存下载信息(文件指针位置) prTw'~(B  
private void write_nPos() FLGk?.x$\  
{ Zo g']=  
try{ ;xzUE`uUfJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); q U]gj@R  
output.writeInt(nStartPos.length); kzt(i Y_6  
for(int i=0;i<nStartPos.length;i++) MP!d4  
{ PX<J&rx  
// output.writeLong(nPos); hFH*B~*:#  
output.writeLong(fileSplitterFetch.nStartPos); )?X-(4  
output.writeLong(fileSplitterFetch.nEndPos); v 8$>rwB  
} (=* cK-3  
output.close(); R,pX:H&#+  
} TrLu~4  
catch(IOException e){e.printStackTrace ();} k3) dEH1z  
catch(Exception e){e.printStackTrace ();} mg*qiScfW  
} UFp,a0|  
oxz OA  
x "^Xj]-  
//读取保存的下载信息(文件指针位置) 0V'nK V"|  
private void read_nPos() Mf&{7%  
{ (]Y 5eM  
try{ rvXWcu-"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K95p>E`9e  
int nCount = input.readInt(); SjwyLc  
nStartPos = new long[nCount]; cp#JBH O  
nEndPos = new long[nCount]; P!+'1KR  
for(int i=0;i<nStartPos.length;i++) cm&I* 0\  
{ `C$:Yf]%nG  
nStartPos = input.readLong(); bO'Sgc[]  
nEndPos = input.readLong(); @I_8T$N=  
} =8; {\  
input.close(); aC%m-m  
} aVK3?y2  
catch(IOException e){e.printStackTrace ();} *Df,Ijh$  
catch(Exception e){e.printStackTrace ();} \E% 'Y  
} r=X}%~_8X  
qoj$]   
S"OR%  
private void processErrorCode(int nErrorCode) "CUty"R 8  
{ 1n:8s'\  
System.err.println("Error Code : " + nErrorCode); DGAX3N;r6{  
} c6X}2a'  
w8Sp <6*  
1oN^HG6O  
//停止文件下载 ENGg ~D  
public void siteStop() /+\uqF8F  
{ dt`{!lts'  
bStop = true; -Xxqm%([71  
for(int i=0;i<nStartPos.length;i++) x)rM/Kq  
fileSplitterFetch.splitterStop(); K)Q]a30  
<xgTS[k  
ML( E o  
} %2XHNW  
} rld67'KcE  
//负责部分文件的抓取 `eIenA  
**FileSplitterFetch.java rmE"rf  
*/ W!6qqi{  
package NetFox; .)<(Oj|4  
j}~86JO+Cw  
2Fq<*pxAY  
import java.io.*; BPdfYu ,il  
import java.net.*; 34d3g  
\hM|(*DL  
WIv?}gi: X  
public class FileSplitterFetch extends Thread { =y/8 ^^  
U2ZD]q  
b#K:_ac5  
String sURL; //File URL ? P( ZA  
long nStartPos; //File Snippet Start Position BI $   
long nEndPos; //File Snippet End Position " e}3:U5n  
int nThreadID; //Thread's ID rfNm&!K  
boolean bDownOver = false; //Downing is over {|1Y:&M?   
boolean bStop = false; //Stop identical .8y3O]  
FileAccessI fileAccessI = null; //File Access interface lsy?Ac  
t=-SH^$SR  
|=$-Wu  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +eX@U;J,g  
{ qeL5D*  
this.sURL = sURL; JvT"bZk( o  
this.nStartPos = nStart; "87ghj_}  
this.nEndPos = nEnd; K00 87}H  
nThreadID = id; s;64N'HH  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 V}SBuQp"  
} XI9js{p  
,B0_MDA +  
unBy&?&p  
public void run() 72oF,42y  
{ p\JfFfC  
while(nStartPos < nEndPos && !bStop) Um: Hrjw  
{ /k<WNZM  
4Rvf  
Oh'Y0_oB>  
try{ %7gkNa  
URL url = new URL(sURL); R0L&*Bjm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4( 1(e  
httpConnection.setRequestProperty("User-Agent","NetFox"); w\DVzeW(  
String sProperty = "bytes="+nStartPos+"-"; pGK;1gVj  
httpConnection.setRequestProperty("RANGE",sProperty); N9vP7  
Utility.log(sProperty); .]sf0S!  
^",ACWF4Sk  
$`- 4Ax4%  
InputStream input = httpConnection.getInputStream(); =Q[b'*o7  
//logResponseHead(httpConnection); T+<A`k: -  
`/~8}Y{  
5<ux6,E1{  
byte[] b = new byte[1024]; j'BMAn ?  
int nRead; m q{];  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ea~:}!-P  
{ ;Hj~n+  
nStartPos += fileAccessI.write(b,0,nRead); Vgyew9>E  
//if(nThreadID == 1) 6p?JAT5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,I_^IitN  
} &bp=`=*  
Ie4hhW  
HjGyj/78w  
Utility.log("Thread " + nThreadID + " is over!"); K"[AxB'F  
bDownOver = true; 9> g,  
//nPos = fileAccessI.write (b,0,nRead); W"k8KODOY  
} stk9Ah  
catch(Exception e){e.printStackTrace ();} y;AL'vm9  
} H03jDM8Q  
} &ZX{R#[L  
8kIR y   
=n' 4?W@  
//打印回应的头信息 ^-[?#]  
public void logResponseHead(HttpURLConnection con) gW1b~( fD  
{ %0mMz.f  
for(int i=1;;i++) SJ};TEA  
{ vJU*>U,  
String header=con.getHeaderFieldKey(i); K a(J52  
if(header!=null) #~.w&~ :  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /M*a,o  
Utility.log(header+" : "+con.getHeaderField(header)); zdEPDd B  
else }LijnHH.  
break; LI6hE cM=  
} Iz{R}#8CZ  
} sPb=82~z  
`QUy;%+  
?w+Ix~k  
public void splitterStop() Zt&6Ua[Y}  
{ @bnG:np  
bStop = true; K&U7H:  
} z ly unJD(  
\a=D  
DVkB$2]  
} FA }_(Hf.[  
.LuB\o$  
QEu=-7@>  
/*  aKd+CO:  
**FileAccess.java 5n ^TRB  
*//文件访问(定位,写) ^-a8V'  
package NetFox; d'|, [p  
import java.io.*; Zb134b'  
UD)e:G[Gat  
9Y<#=C  
public class FileAccessI implements Serializable{ C>[fB|^  
A,) VM9M_l  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >N?2""  
RandomAccessFile oSavedFile; yx<WSgWZ[  
long nPos; XbZ*&  
60)iw4<wf  
hAjM1UQ,Y  
public FileAccessI() throws IOException d)"?mD:m/M  
{ bC3 F  
this("",0); 4ON_$FUe  
} _%x4ty  
]Y| 9?9d  
s#S%#LM  
public FileAccessI(String sName,long nPos) throws IOException vc]cNz:mQ  
{ *\o/q[  
oSavedFile = new RandomAccessFile(sName,"rw"); 1<h>B:  
this.nPos = nPos; Vm|Y$ C  
oSavedFile.seek(nPos); {" 4e+y  
} p*8-W(u)  
\6 93kQ  
ee/&/Gt  
public synchronized int write(byte[] b,int nStart,int nLen) #%FN>v3e  
{ 3w!c`;c%  
int n = -1; /2RajsK  
try{ )Y8",Ig  
oSavedFile.write(b,nStart,nLen); ZJjTzEV%^B  
n = nLen; {h KjD"?  
} ?9X&tK)E-  
catch(IOException e) ne>g?"Pex{  
{ LjH*rjS4  
e.printStackTrace (); 033T>qY  
}  N<L`c/  
2PR^:h2  
7HHysNB"w  
return n; 0ilCS[`b  
} fof2 xcH!  
Ol')7d&  
\@;\t7~  
} '/I:^9  
n6(.{M;  
tdF9NFMD  
/* A~dQ\M  
**SiteInfoBean.java L}yyaM)  
*/ gBf4's  
package NetFox; o|j*t7  
IjfxR mV  
$j 5,%\4<  
public class SiteInfoBean { G8IY#  
T'fcc6D5p  
oQ7]= |  
private String sSiteURL; //Site's URL /V?H4z[G  
private String sFilePath; //Saved File's Path {gKN d*[*  
private String sFileName; //Saved File's Name w~@-9<^K]v  
private int nSplitter; //Count of Splited Downloading File (.Lrmf@hI7  
lZQ /W:OE  
$oLU; q%  
public SiteInfoBean() %ObD2)s6:^  
{//nSplitter的缺省值为5 3[XQR8o  
//default value of nSplitter is 5 h)v^q: ='  
this("","","",5); Ft@Wyo`^  
} #2tCV't  
ZE `lr+_Y  
XTDE53Js&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 60Z]M+8y8  
{ w&BGJYI  
sSiteURL= sURL; E&B{5/rv  
sFilePath = sPath; - ~4+w  
sFileName = sName; w^1Fi8+  
this.nSplitter = nSpiltter; R1-k3;v^  
= zl= SLe  
?R5'#|EyX  
} )n=ARDd^e  
V5D`eX9  
rQP"Y[  
public String getSSiteURL() @:x"]!1  
{ AA:no=  
return sSiteURL; 7);:ZpDv%L  
} |8)Xc=Hz  
t!_x(u  
Be}$I_95\P  
public void setSSiteURL(String value) o/,NGU  
{ > 4oY3wk8  
sSiteURL = value; M_``'gw  
} {?{U,&  
2BzqY`O  
:ZxLJK9x1  
public String getSFilePath() 'xFYUU]#T^  
{ (}:C+p 'I  
return sFilePath; :Au /2  
} hFvi 5I-b  
9zgNjjCl]  
Z v0C@r  
public void setSFilePath(String value) P=H+ #  
{ o7+>G~i  
sFilePath = value; L<(VG{)Z  
} Zwe[_z!*D  
J Lb6C 52  
Q;nAPS  
public String getSFileName() m h;X~.98  
{ Icp0A\L@  
return sFileName; 8G ]w,eF  
} [$ :  
^^(<c,NX#M  
;5 <-)  
public void setSFileName(String value) FyG6 !t%  
{ 0>!/rR7  
sFileName = value; V)D-pV V  
} Poa?Ej  
&C-;Sa4  
P ,K\  
public int getNSplitter() H:a|x#"  
{ AH.9A_dG  
return nSplitter; /f1'm@8;  
} *rqm8z50a  
GLKO]y  
2r ];V'r  
public void setNSplitter(int nCount) he )ulB  
{ 1h"_[`L'  
nSplitter = nCount; #/j={*-  
} wAbp3hX  
} {4ptu~8  
#B\=Aa`*  
JatHSW7j9  
/* ^Y^"'"  
**Utility.java YDiN^q7  
*/ {@M14)-x>_  
package NetFox; z^s ST  
`HUf v@5  
!v !N>f4S$  
public class Utility { )u@t.)ChAV  
"E*8h/4u  
OoP@-D"e  
public Utility() { U <tc4^  
{ M@?"t_e1  
J"[3~&em  
=8{*@>CX  
} N"DY?6  
?gV'(3 !  
//线程睡眠 ~Sy-ga J  
public static void sleep(int nSecond) \iMyo  
{ ma}}Sn)Q  
try{ 6b:DJ  
Thread.sleep(nSecond); $cK^23H/Fj  
} +0pW/4x  
catch(Exception e) PW_`qP:  
{ i+~QDo(Pi  
e.printStackTrace (); ~4s-S3YzaM  
} Um ;kd&#x  
} KR3-Hb4  
:'w?ye[e  
//日志 g'G8 3F  
public static void log(String sMsg) 3kLOoL?  
{ Kp_jy.e7&  
System.err.println(sMsg); *d l"wH&  
} I=YCQ VvA  
$e/*/.  
IYNMU\s  
public static void log(int sMsg) MOV =n75  
{ uFe'$vI  
System.err.println(sMsg); /!b x`cKG  
} ci7~KewJ*  
} U5 rxt^  
0]a15  
WzG07 2w  
/* *4#on>  
**TestMethod.java P`sN&Y~m  
*/ Tcs3>lJ}   
package NetFox; v_-ls"l  
f-vK}'Z`,  
* NMQ  
public class TestMethod { z\[(g  
q<}PM  
Kcn\g.  
public TestMethod()  EW5]!%  
{ ///xx/weblogic60b2_win.exe I2*oTUSik  
try{ ^"`Z1)V  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (^S5Sc=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `9EVB;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); L; C|ow^c  
fileFetch.start(); _z:Qhe  
} 'aPCb`^;w  
catch(Exception e){e.printStackTrace ();} wU0K3qZL  
Ak|b0l>^  
&9h  
} n49s3|#)G  
f)tc4iV  
~\bHfiIDy  
public static void main(String[] args) Fhi5LhWe+.  
{ *'^:S#=  
new TestMethod(); %EB;1  
} 0HPO" x3-O  
} Q}z{AZ  
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