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http断点续传简单实现(java)

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/* , ^nUi c  
**SiteFileFetch.java :$WRV-  
*/ ~ce.&C7cR  
package NetFox; p|((r?{  
import java.io.*; =4[zt^WX"  
import java.net.*; O[]+v  
H(AYtnvB  
BZj[C=#x  
public class SiteFileFetch extends Thread { .D)}MyKnu  
1>2397  
`DwlS!0  
SiteInfoBean siteInfoBean = null; //文件信息Bean iTX.? *  
long[] nStartPos; //开始位置 &5a>5ZG}  
long[] nEndPos; //结束位置 3w@)/ujn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 uYl ?Q  
long nFileLength; //文件长度 My ^pQ]@  
boolean bFirst = true; //是否第一次取文件 ^v},Sa/ot]  
boolean bStop = false; //停止标志 z}&<D YD  
File tmpFile; //文件下载的临时信息 eQc!@*:8U  
DataOutputStream output; //输出到文件的输出流 e nNn*.*|  
rYLNV!_  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Z(.Tl M2h  
public SiteFileFetch(SiteInfoBean bean) throws IOException d/^^8XUK  
{ VTHDGBU  
siteInfoBean = bean; -or9!:8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); R%Z} J R.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Fg~,1[8w<  
if(tmpFile.exists ()) kA3kh`l  
{ yG_#>3sD+%  
bFirst = false; '!0CwZ 7  
read_nPos(); jIl-}/2  
} x:2_FoQ  
else BgRiJFa.d[  
{ ''6"Xi|5  
nStartPos = new long[bean.getNSplitter()]; +vuW 9  
nEndPos = new long[bean.getNSplitter()]; r1\.Jz  
} DK- =Q~`!  
R0|X;3  
mZ5UaSG  
rS jC/O&b  
} qEpBzQ&gX6  
)uaB^L1  
#Y:/^Q$_qS  
public void run() ZibODs=f;  
{ qM`SN4C  
//获得文件长度 Vlf@T  
//分割文件 5 9 09O  
//实例FileSplitterFetch  2AluH8X/  
//启动FileSplitterFetch线程 ,s2.l/5r;C  
//等待子线程返回 YK-R|z6K  
try{ &sRyM'XI  
if(bFirst) WP>O7[|  
{ @s/ qOq?  
nFileLength = getFileSize(); h"'f~KM9a>  
if(nFileLength == -1) s.~SV"  
{ #4hP_Vhc  
System.err.println("File Length is not known!"); kju:/kYA  
} ,^[s4 =3X?  
else if(nFileLength == -2) Qw ^tzP8  
{ SX4p(t  
System.err.println("File is not access!"); k.0C*3'  
} ( u _ sz  
else )CB?gW  
{ zqeU>V~<F  
for(int i=0;i<nStartPos.length;i++) 51&T`i  
{ f8j^a?d|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Glwpu-@X  
} {Xp.}c  
for(int i=0;i<nEndPos.length-1;i++) ?-VN+ d7  
{ &a:aW;^A7  
nEndPos = nStartPos[i+1]; N+tS:$V  
} {/Cd^CK  
nEndPos[nEndPos.length-1] = nFileLength; ~)Z`Q  
} D9Z5g3s7R  
} _&M>f?l  
`+6HHtF  
A gPg0(G  
//启动子线程 V+8+ 17^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; w;_Ds  
for(int i=0;i<nStartPos.length;i++) WS(c0c  
{ &zT~3 >2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w5;EnI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), k9,"`dk@  
nStartPos,nEndPos,i); Y}6)jzBV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UvI!e4_  
fileSplitterFetch.start(); pI!55w|  
} ) ad-s  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w7C=R8^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o#Y1Uamkf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", IIPf5 Z}A  
nEndPos = " + nFileLength); pxF!<nN1,  
// fileSplitterFetch[nPos.length-1].start(); 9f @)EKBK  
0(kp>%mbB  
+u#x[xO  
//等待子线程结束 v Zxy9Wmc  
//int count = 0; 0jmlsC>  
//是否结束while循环 ?m!FM:%  
boolean breakWhile = false; .jKO 6f  
zk]~cG5dT/  
e'6?iLpy  
while(!bStop) ..t=Y#  
{ 8ah]D  
write_nPos(); r:IU +3  
Utility.sleep(500); OTm`i>rB  
breakWhile = true; r3kI'I|bq  
RoTT%c P_  
)t4C*+9<U  
for(int i=0;i<nStartPos.length;i++) phdN9<Z  
{ c1^3lgPv  
if(!fileSplitterFetch.bDownOver) p c],H  
{ +D@R'$N  
breakWhile = false; ?,NAihN]  
break; oW_WW$+N  
} (nzt}i0  
} V6k9L*VP  
if(breakWhile) `et<Z  
break; *v9G#[gG  
[>0r'-kI  
+M*a.ra0OF  
//count++; 8M|Q^VeT,1  
//if(count>4) ,aJrN!fzU  
// siteStop(); vEsSqzc  
} 2R!W5gs1<  
}FXRp=s  
3XRG"  
System.err.println("文件下载结束!"); D6t]E)FH  
} *E]\l+]J  
catch(Exception e){e.printStackTrace ();} lySaJ d  
} NSq"\A\  
-AE/,@\P  
<'-me09C*  
//获得文件长度 (0+m&, z  
public long getFileSize() $W]bw#NH  
{ Oc.>$  
int nFileLength = -1; NEk [0  
try{ =FnZkJ  
URL url = new URL(siteInfoBean.getSSiteURL()); Jj " {r{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #t O!3=0  
httpConnection.setRequestProperty("User-Agent","NetFox"); >U)O@W)  
sn( }5;  
`9-Zg??8r  
int responseCode=httpConnection.getResponseCode(); J$;)TI  
if(responseCode>=400) }>w4!  
{ 4Z] 35*  
processErrorCode(responseCode); C#Jj;Gd  
return -2; //-2 represent access is error kQ8WO|bA  
} tpN}9N  
UwU]l17~  
UL%ihWq   
String sHeader; F?B=:8,}  
#k)\e;,X  
ooQ(bF  
for(int i=1;;i++) B^9 #X5!  
{ .yPx'_e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZTZE_[  
//Utility.log(in.readLine()); H~Cfni;  
sHeader=httpConnection.getHeaderFieldKey(i); TE~@Bl;{?c  
if(sHeader!=null) H JiP:{  
{ ]@YQi<d2^  
if(sHeader.equals("Content-Length")) C)w *aU,(  
{ ,whNh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mxGN[ %ve  
break; V*}zwm s6  
} m##=iB|;  
} 9:o3JGHSc  
else %Qq)=J<H ;  
break; Xdt+ \}\  
} K }BX6dA  
} w C"%b#(}  
catch(IOException e){e.printStackTrace ();} S41>VbtEp  
catch(Exception e){e.printStackTrace ();} P{18crC[1  
SO/]d70HG  
pZxL?N!  
Utility.log(nFileLength); ;\+0H$  
*q{UipZbx  
$Stu-l1e a  
return nFileLength; $P3nP=mf  
} [3Rj?z"S  
5b p"dIe  
Qs:r@"hE  
//保存下载信息(文件指针位置) s 'x mv{|  
private void write_nPos() A]$+ `uS\  
{ k#xpY!'7  
try{ T"U t).  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5g5NTm`=<  
output.writeInt(nStartPos.length); GwBQ p Njy  
for(int i=0;i<nStartPos.length;i++) |T*qAJ8c  
{ R:N-y."La.  
// output.writeLong(nPos); +ctv]'P_  
output.writeLong(fileSplitterFetch.nStartPos); K5&C}Ey1  
output.writeLong(fileSplitterFetch.nEndPos); LnS >3$t*  
} MFuI&u!g:  
output.close(); c ?XUb[  
} avu,o   
catch(IOException e){e.printStackTrace ();} ;!?K.,N:N  
catch(Exception e){e.printStackTrace ();} o"[bIXf-h  
} $:!T/*p*  
Hw&M2a  
Bq_P?Q+\  
//读取保存的下载信息(文件指针位置) 1o>R\g3  
private void read_nPos() 8[;oUVb5  
{ (B<AK4G  
try{ KTt$Pt/.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Xkom@F~]  
int nCount = input.readInt(); ton`ji\^  
nStartPos = new long[nCount]; :g[x;Q [@  
nEndPos = new long[nCount]; {LHe 6#  
for(int i=0;i<nStartPos.length;i++) X>7]g670@  
{ rJp6d :M  
nStartPos = input.readLong(); ]bb}[#AY  
nEndPos = input.readLong(); C} _:K)5q  
} ( y*X8  
input.close(); |wQZ~Ux:  
} ue<<Y"NR  
catch(IOException e){e.printStackTrace ();} WG}CPkj  
catch(Exception e){e.printStackTrace ();} "B3:m-'  
} X@U 1Ri  
**w~  
y4We}/-<  
private void processErrorCode(int nErrorCode) H^;S}<pxW  
{ U^BXCu1km  
System.err.println("Error Code : " + nErrorCode); 2_n*u^X:_  
} 3Lki7QW`  
K/v-P <g  
cu!bg+,zl  
//停止文件下载 9Pk3}f)a  
public void siteStop() i03}f%JnuO  
{ ^jjJM|a  
bStop = true; E :=KH\2f  
for(int i=0;i<nStartPos.length;i++) x*8f3^ wE  
fileSplitterFetch.splitterStop(); E(kpK5h{  
SoU'r]k1x  
Pl& `&N;  
} =v$s+`cP  
} KGmc*Jwy  
//负责部分文件的抓取 wn|@D<  
**FileSplitterFetch.java ^@L l(?  
*/ I7z/GA\x  
package NetFox; J?quYlS  
cN}A rv  
&d3'{~:  
import java.io.*; I@Z*Nu1L  
import java.net.*; np\2sa`  
*M<BPxh0w]  
Dh(T) yc  
public class FileSplitterFetch extends Thread { !riMIl1  
f\_!N "HW  
[j]J_S9jJ  
String sURL; //File URL ec4%Wk2  
long nStartPos; //File Snippet Start Position ]!G>8Rc  
long nEndPos; //File Snippet End Position <`j[;>O  
int nThreadID; //Thread's ID 2vdQ&H4  
boolean bDownOver = false; //Downing is over *a,.E6C*  
boolean bStop = false; //Stop identical )  v5n "W  
FileAccessI fileAccessI = null; //File Access interface 7h9[-d6  
4O_+4yS  
3r:)\E+Q_  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *r,&@UB  
{ :8Ts'OGwI  
this.sURL = sURL; eO PCYyN  
this.nStartPos = nStart; k.xv+^b9Q  
this.nEndPos = nEnd; @*O{*2  
nThreadID = id; R5&$h$[/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ->2wrOH|H  
} %^?3s5PXD  
uj9tr`Zh  
P,;b'-5C  
public void run() %>9+1lUhV  
{ -C-OG}XjI  
while(nStartPos < nEndPos && !bStop) 9#T%bB "J  
{ ?V)C9@bp  
1;:t~Y  
nR@,ouB-$  
try{ +>:_kE]?nX  
URL url = new URL(sURL); `TD%M`a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?I2k6%a  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?WQd  
String sProperty = "bytes="+nStartPos+"-"; Fr3d#kVR  
httpConnection.setRequestProperty("RANGE",sProperty); pG F5aF7T  
Utility.log(sProperty); CziaxJ  
x"l lX  
g[wP!y%V  
InputStream input = httpConnection.getInputStream(); opcR~tg@r  
//logResponseHead(httpConnection); O})u'  
J={OOj  
H")N_BB  
byte[] b = new byte[1024]; /=YqjZTCq  
int nRead; B#k3"vk#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5 2@udp  
{ a j@C0  
nStartPos += fileAccessI.write(b,0,nRead); T5dUJR2k$  
//if(nThreadID == 1) $dZ>bXUw:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &.  =}g]  
} Z"n'/S:q  
/pIb@:Y1?  
T7lj39pJq  
Utility.log("Thread " + nThreadID + " is over!"); ,+ \4 '`  
bDownOver = true; *0&4mi8  
//nPos = fileAccessI.write (b,0,nRead); 2 ]DCF  
} 7Z`Mt9:Ht  
catch(Exception e){e.printStackTrace ();} N[bR&# p  
} %%+mWz a  
} ~AC P%QM=  
SGBVR^  
!M]%8NTt2  
//打印回应的头信息 x?f0Hk+  
public void logResponseHead(HttpURLConnection con) o[6vxTH  
{ (o*e<y,}W  
for(int i=1;;i++) vTMP&a'5L  
{ 4kaE}uKU  
String header=con.getHeaderFieldKey(i); xOV A1p b,  
if(header!=null) o!s%h!%L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $d2kHT  
Utility.log(header+" : "+con.getHeaderField(header)); {8{t]LK<  
else 8_<&f%/  
break; esh$*)1  
} u 5Eo  
} ^x_ >r6  
;zZ,3pl-E  
ovQS ET18b  
public void splitterStop() ~}$\B^z+  
{ q?;*g@t  
bStop = true; 4/HY[FT  
} |6sT,/6  
% UW=:  
A#Q0{z@H  
} Ox7uG{t$#  
1Nl&4YLO  
Q/QQ:t<XUi  
/* qab) 1ft  
**FileAccess.java VBbUl|X\  
*//文件访问(定位,写) )BF \!sTn  
package NetFox; u>,lf\Fgz  
import java.io.*; XN~#gm#  
e0v9uQ%F5  
`jb0 +{08  
public class FileAccessI implements Serializable{ ^ o $W  
[j:}=:feQ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ZRXI?Jr%  
RandomAccessFile oSavedFile; MfXt+c`r  
long nPos; ~A[YnJYA#  
8/Et&TJ`  
IOsXPf9@  
public FileAccessI() throws IOException u Q:ut(  
{ VD9 q5tt7  
this("",0); vx\nr8'k  
} y3={NB+  
`d}W;&c  
I"8d5a}  
public FileAccessI(String sName,long nPos) throws IOException j<l#qho{h  
{ 8qFUYZtY  
oSavedFile = new RandomAccessFile(sName,"rw"); 69[V <1  
this.nPos = nPos; < 72s7*Rv  
oSavedFile.seek(nPos); Yl)eh(\&J  
} ERp:EZ'  
i(M(OR/4  
u;+%Qh  
public synchronized int write(byte[] b,int nStart,int nLen) $:f.Krj  
{ tk`: CT *  
int n = -1; 84[|qB,ML  
try{ }iPo8Ra  
oSavedFile.write(b,nStart,nLen); tXf}jU}  
n = nLen; 2j8Cv:{Nn%  
} #joF{ M{  
catch(IOException e) }': EJ~H  
{ /{fZH,!L  
e.printStackTrace (); F3r S6_  
} 9USrgY6_  
!: m`9o8  
" t5 +*  
return n; "2ZIoa!^  
} u{g]gA8s  
:FoO Q[Q  
<WM -@J(1  
} x9xzm5  
DgDSVFk ~  
2-8YSHlh  
/* .HyjL5r-  
**SiteInfoBean.java }Q`/K;yq  
*/ pGY [f@_x-  
package NetFox;  Y[f,ia  
b%3Q$wIJ6  
W:`5nj]H9  
public class SiteInfoBean { 6b%`^B\  
l*QIoRYFW  
- waX#U T=  
private String sSiteURL; //Site's URL rU; g0'4e  
private String sFilePath; //Saved File's Path 8'3"uv  
private String sFileName; //Saved File's Name AU0$A403  
private int nSplitter; //Count of Splited Downloading File ow-+>Y[qZ  
Ezi' 2Sc  
"I5uDFZR&  
public SiteInfoBean() |*%/ovg+  
{//nSplitter的缺省值为5 jZa25Z00  
//default value of nSplitter is 5 >oe4mW  
this("","","",5); B1y<.1k  
} 6eD(dZ  
`ajx hp  
h^['rmd  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;rNd701p"  
{ ` !zQ  
sSiteURL= sURL; n)tU9@4Np  
sFilePath = sPath; B:e.gtM5  
sFileName = sName; vAi"$e  
this.nSplitter = nSpiltter; NV:>a  
Mx^y>\X)v  
kX igX-  
} b+W)2rFO  
ah 4kA LO  
*]FgfttES  
public String getSSiteURL() 'n>K^rA  
{ $X`bm*  
return sSiteURL; Mg#`t$ u  
} U%Dit  
{*sGhGwr  
0xN!DvCg>.  
public void setSSiteURL(String value) (2: N;  
{ <H<!ht%q3  
sSiteURL = value; \.5F](:  
} .H ,pO#{;  
Dp^"J85}   
E yd$fcRK  
public String getSFilePath() @o`sf-8x  
{ +IvNyj|  
return sFilePath; "Lb f F  
} n.@#rBKZ  
aZP 2R"  
z|uOJ0uK  
public void setSFilePath(String value) ]n~yp5Nbr  
{ eUYZxe :6  
sFilePath = value; P=2wkzeJj  
} w(/7Jt$  
sD{ j@WEZ  
bdCykG-  
public String getSFileName() x,w8r+~5  
{ yXkt:O,i  
return sFileName; _0w1 kqW  
} `q^(SM  
^Fn%K].X  
Bu&So|@TL  
public void setSFileName(String value) [U swf3  
{ S[Vtq^lU  
sFileName = value; |0lLl^zp  
} kPWBDpzN  
:RHm*vt  
p*Xix%#6  
public int getNSplitter() K6-6{vt  
{ 5Wo5 n7o  
return nSplitter; YDW|-HIF  
} jg?bf/$s  
 %W(^6p!  
nkTYWw  
public void setNSplitter(int nCount) )u<eO FI+  
{ C B6A}m  
nSplitter = nCount; vlvvi()  
} _wmI(+_  
} 00"CC  
/\d(c/,4  
rjXnDh]MC  
/* *u}'}jC1X  
**Utility.java 3\1#eK'TK.  
*/ h 5Hr[E1  
package NetFox; Sg_O?.r  
9YAM#LBTWi  
*-6?  
public class Utility { iM"asEU  
v_.HGG S  
0JK2%%  
public Utility() +N7"EROc  
{ 0iF-}o  
ndqckT@93  
eIsT!V" 7  
} )Z("O[  
p=H3Q?HJ}  
//线程睡眠 s"q=2i  
public static void sleep(int nSecond) &Bm&i.r  
{ 02(h={  
try{ qIz}$%!A  
Thread.sleep(nSecond); 0t+])>  
} CG.,/]_  
catch(Exception e) %Uf'+!4l`  
{ >otJF3zw   
e.printStackTrace (); Xo\S9,s{  
} \X5 3|Y;=  
} ';Nu&D#Ph  
G0Hs,B@5?  
//日志 1 =^  
public static void log(String sMsg) sCkO0dl8  
{ (vnoP< 0  
System.err.println(sMsg); Cs#w72N  
} JYQ.EAsr!  
)nOE 8y/  
ctHEEFWm  
public static void log(int sMsg) F{\=PCZ>7  
{ *,&S',S-  
System.err.println(sMsg); 9n"V\e_R  
} Kr]z]4.d@  
} kutJd{68  
>L=;"+B0U&  
modC6d%  
/* "W5rx8a  
**TestMethod.java #3+~.,X9  
*/ 0p `")/  
package NetFox; ke\[wa_!6b  
W+\?~L.  
`c9'0*-  
public class TestMethod { l!:^6i  
lm*g Gy1i  
2T?TM! \Q  
public TestMethod() zqf[Z3  
{ ///xx/weblogic60b2_win.exe o,*=$/or  
try{ x6v,lR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); BPewc9RxV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); P$OUi!"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xCq'[9oU  
fileFetch.start(); tDt :^Bc  
} NH4?q!'G  
catch(Exception e){e.printStackTrace ();} SO_>c+Dw  
s4bv;W  
5z Kqb  
} ]Jn2Ra"j  
JD*8@N  
N 2Ssf$  
public static void main(String[] args) >Nh`rkR2[  
{ = ^s$ <  
new TestMethod(); l `R KqT+  
} /NU103F yt  
} ke]Yfwk  
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