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http断点续传简单实现(java)

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/* $R5-JvJJH  
**SiteFileFetch.java rTJWftH!  
*/ b$ eJH  
package NetFox; eyG.XAP  
import java.io.*; 0VZj;Jg}q  
import java.net.*; m6 gr!aT  
3k(?`4JJ  
S`^W#,rj  
public class SiteFileFetch extends Thread { t2gjhn^p  
zJy{Ry[Sb  
%)e+w+  
SiteInfoBean siteInfoBean = null; //文件信息Bean *~"`&rM(  
long[] nStartPos; //开始位置 0k>&MkM\^  
long[] nEndPos; //结束位置 6]3 ZUH;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -,tYfQ;:  
long nFileLength; //文件长度 7wnzef?)  
boolean bFirst = true; //是否第一次取文件 `sXx,sV?B  
boolean bStop = false; //停止标志 _aGdC8%[  
File tmpFile; //文件下载的临时信息 {+EPE2X=C  
DataOutputStream output; //输出到文件的输出流 i_@RWka<  
u rOGOa$  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) .G]# _U  
public SiteFileFetch(SiteInfoBean bean) throws IOException gdT_kb5HL8  
{ {3R ax5Ty  
siteInfoBean = bean; ^/uGcz|.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Rb0{t[IU  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }X?*o `sW  
if(tmpFile.exists ()) WWL Vy(  
{ _7<U[63  
bFirst = false; :6 fQE#(s&  
read_nPos(); QUDVsN#  
} Ss:,#|   
else +g[B &A!d+  
{ K_aN7?#.v`  
nStartPos = new long[bean.getNSplitter()]; ._3NqE;  
nEndPos = new long[bean.getNSplitter()]; rifxr4c[X>  
} `lhLIQ'j  
<j#EyGAV  
-T8 gV1*(<  
1sJN^BvuG  
} lN'/Z&62  
""d>f4,S  
yd~fC:_ ]  
public void run() t;]egk  
{ bM-Rj1#Lo  
//获得文件长度 {Jc!T:vJ  
//分割文件 h~@+M5r,  
//实例FileSplitterFetch [ lW "M  
//启动FileSplitterFetch线程 ni> ;8O]=  
//等待子线程返回 NjxW A&[ng  
try{ /WfVG\NF  
if(bFirst) g@k9w{_  
{ (ZK >WoV  
nFileLength = getFileSize(); jh G7sS|  
if(nFileLength == -1) DE ws+y-*  
{ m =}X$QF`^  
System.err.println("File Length is not known!"); ~'MWtDe:Z8  
} .B13)$C  
else if(nFileLength == -2) G#: !wI  
{ mW-W7-JhO7  
System.err.println("File is not access!"); clw91yrQn  
} 'qJ-eQ7e  
else 02[II_< 1  
{ R!,)?j;  
for(int i=0;i<nStartPos.length;i++) gxM8IQ  
{ "~<~b2Y"5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jVIpbG4 4  
} 5XI*I( .%/  
for(int i=0;i<nEndPos.length-1;i++) A.O~'')X  
{ ^mpB\D)q  
nEndPos = nStartPos[i+1]; @UX@puK`/  
} ;vdgF  
nEndPos[nEndPos.length-1] = nFileLength; @W8}N|jek  
} DZRxp,  
} l`&6W?C  
c5e\ckqm^  
[r8 d+  
//启动子线程 MF}Lv1/[-J  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?8@*q6~8  
for(int i=0;i<nStartPos.length;i++) C4tl4df9  
{ E{ s|#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l|A8AuO*?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Mqp68%  
nStartPos,nEndPos,i); xUi!|c  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QJWES%m`  
fileSplitterFetch.start(); [Z\1"m  
} ?w/nZQWi  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .~L4#V{c~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); zI!R-Nb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (H+[^(3d2  
nEndPos = " + nFileLength); ~4MjJKzA  
// fileSplitterFetch[nPos.length-1].start(); m 1i+{((  
yQ{_\t1Wd  
R"gm]SQ/  
//等待子线程结束 P &0cF{  
//int count = 0; X-#mv|3  
//是否结束while循环 JK"uj%  
boolean breakWhile = false; HF+fk*_Q  
' u};z:t  
sDm},=X}  
while(!bStop) &6=ZT:.6Te  
{ )]> '7] i  
write_nPos(); b^DV9mO4J  
Utility.sleep(500); ws>Iyw.u  
breakWhile = true; }#>d2 =T$  
x[W]?`W3r~  
-#;VFSz,9*  
for(int i=0;i<nStartPos.length;i++) ptyDv  
{ H)T# R?  
if(!fileSplitterFetch.bDownOver) o!r4 frP  
{ BON""yIC   
breakWhile = false; !9LAXM  
break; ' 5 qL  
} B4 Af  
} S aet";pf`  
if(breakWhile) 6XL9 qb~X  
break; >ha Ixs`9  
efkie}  
n3g WM C  
//count++; UN?T}p- oF  
//if(count>4) C%?D E@k  
// siteStop(); Pq\V($gN  
} Rn(F#tI  
I+?$4SC  
2mU-LQ1WN  
System.err.println("文件下载结束!"); zGd*Q5l  
} T.P Z}4  
catch(Exception e){e.printStackTrace ();} |ezO@  
} A;j$rGx  
FJ,\?ooGf  
*5'6 E'  
//获得文件长度 >\x_"oR  
public long getFileSize() pD_eo6xX  
{ 5`'au61/2  
int nFileLength = -1; ?Gv!d  
try{ `) !2E6 =  
URL url = new URL(siteInfoBean.getSSiteURL()); +6)kX4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9 roth  
httpConnection.setRequestProperty("User-Agent","NetFox"); j X!ftm2  
UFAMbI  
hPi :31-0  
int responseCode=httpConnection.getResponseCode(); P}WhE  
if(responseCode>=400) X`v79`g_  
{ X1V}%@3:  
processErrorCode(responseCode); MN M>  
return -2; //-2 represent access is error ]#-/i2-K  
} i 2} =/  
iLd"tn'  
f+aS2k(e>  
String sHeader; QRZTT qG  
9Glfi@.  
*ez~~ Y  
for(int i=1;;i++) (=tF2YBV  
{ > <  _Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \ [^) WQ  
//Utility.log(in.readLine()); ]V769B9  
sHeader=httpConnection.getHeaderFieldKey(i); {9|$%4kRl  
if(sHeader!=null) J(&M<<%  
{ 0e:QuV2X  
if(sHeader.equals("Content-Length")) iMeRQYW  
{ 9s6>9hMb)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); zmfRZ!Eh  
break; %)hIpxOrX  
} J%-lw{FC  
} vH?+JN"A  
else pT;-1c%:  
break; &~JfDe9IS  
} g*r{!:,t  
} %f> |fs  
catch(IOException e){e.printStackTrace ();} si!9Gz;  
catch(Exception e){e.printStackTrace ();} >7(~'#x8A"  
>&Ui*  
-}qGb}F8!  
Utility.log(nFileLength); {Fp`l\,  
s8yTK2v2\  
}!yD^:[ 5  
return nFileLength; 0O['-x  
} X6N]gD  
d,J<SG&L&  
kq}eUY]  
//保存下载信息(文件指针位置) fF9oYOh|  
private void write_nPos() E%2!C/+B  
{ >]XaUQ-  
try{ ND55`KT4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); o +QzQ+ Z  
output.writeInt(nStartPos.length); : ` 6$/DK  
for(int i=0;i<nStartPos.length;i++) id#k!*$7  
{ G0; EbJ/&  
// output.writeLong(nPos); WP@JrnxO\`  
output.writeLong(fileSplitterFetch.nStartPos); < ;,S"e  
output.writeLong(fileSplitterFetch.nEndPos); Th;gps%b  
} J.e8UQ@=5  
output.close(); D@r n@N  
} qvfAG 0p  
catch(IOException e){e.printStackTrace ();} ekl? K~  
catch(Exception e){e.printStackTrace ();} ({H+ y 9n  
} o~.o^0Y  
Puth8$  
gcW{]0%L^  
//读取保存的下载信息(文件指针位置) K@j^gF/0B  
private void read_nPos() c]aK N  
{ ;/)Mcx]n  
try{ d0}%%T  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DvRA2(M  
int nCount = input.readInt(); _^xh1=Qr}n  
nStartPos = new long[nCount]; |p8"9jN@}c  
nEndPos = new long[nCount]; |!xfIR>=F  
for(int i=0;i<nStartPos.length;i++) [`zbf_RyO  
{ =S[FJaIu7  
nStartPos = input.readLong(); 6Er0o{iI  
nEndPos = input.readLong(); e2-70UvW^  
} +Sdx8 Z5  
input.close(); vA "`0  
} ReB(T7Vk=  
catch(IOException e){e.printStackTrace ();} 4Fr7jD,#k  
catch(Exception e){e.printStackTrace ();} Q&.IlVB[  
} iQm.]A  
@^:7UI_  
\Sq"3_m4T  
private void processErrorCode(int nErrorCode) r_V2 J{B  
{ ZXsY-5$#d-  
System.err.println("Error Code : " + nErrorCode); JW%/^'  
} =~W0~lxX  
` r'0"V  
S4{Mu(^xT  
//停止文件下载 %];h|[ax]  
public void siteStop() z7@(uIl=X  
{ Ah"'hFY  
bStop = true;  ENYF0wW  
for(int i=0;i<nStartPos.length;i++) 9#EHXgz  
fileSplitterFetch.splitterStop(); ;5Wx$Yfx  
_86*.3fQG  
S-M)MCL  
} !}L~@[v,uL  
} aX[1H6&=7  
//负责部分文件的抓取 x '=3&vc4  
**FileSplitterFetch.java $xUzFLh=`  
*/ MKVfy:g%So  
package NetFox; )4'x7Qg/  
M~ i+F0  
Q2[prrk%j  
import java.io.*; k binf  
import java.net.*; :p\(y  
/+x#V!zM  
wzDk{4U  
public class FileSplitterFetch extends Thread { 6HEqm>Yau  
C`yvBt40r  
'd2qa`H'}B  
String sURL; //File URL =YXe1$ $  
long nStartPos; //File Snippet Start Position j*eUF-J1  
long nEndPos; //File Snippet End Position 4[LLnF--  
int nThreadID; //Thread's ID ElEv(>G*  
boolean bDownOver = false; //Downing is over ]M+VSU  
boolean bStop = false; //Stop identical Z92iil;t  
FileAccessI fileAccessI = null; //File Access interface :~ZqB\>i  
eC+"mhB  
QX/X {h6  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *%OYAsc  
{ ;LQ# *NjL\  
this.sURL = sURL; l\T!)Ql  
this.nStartPos = nStart; PkPDVv  
this.nEndPos = nEnd; &*G5J7%w  
nThreadID = id; d%#!nq{vd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m?D <{BQ;  
} \uU=O )  
(b/A|hl  
LC,*H0  
public void run() V9fGVDl;  
{ ;0w^ud  
while(nStartPos < nEndPos && !bStop) <fC@KY>#  
{ S' (cqO}=F  
Hhe{ +W@~  
yyY~ *Le  
try{ lC'{QUC  
URL url = new URL(sURL); u0bfX,e2U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *PSvHXNi  
httpConnection.setRequestProperty("User-Agent","NetFox"); V-KL%  
String sProperty = "bytes="+nStartPos+"-"; bH\'uaJ  
httpConnection.setRequestProperty("RANGE",sProperty); vU_d=T%$  
Utility.log(sProperty); (~j,mk  
T~i%j@Q.6  
w24{_ N  
InputStream input = httpConnection.getInputStream(); zb>f;[  
//logResponseHead(httpConnection); aN^]bs?R  
[%j?.N  
?a'6EAErC  
byte[] b = new byte[1024]; > 63)z I  
int nRead; <*s"e)XeqF  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^[{`q9A#d  
{ Q0zW ]a  
nStartPos += fileAccessI.write(b,0,nRead); {fGd:2dh  
//if(nThreadID == 1) Usa+b A  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jOUK]>ox:  
} csH2_+uG  
?muDTD%c  
<Rcu%&;i  
Utility.log("Thread " + nThreadID + " is over!"); [[R7~.;  
bDownOver = true; !dU9sB2  
//nPos = fileAccessI.write (b,0,nRead); ;y>S7n>n:  
} o"rq/\ovv  
catch(Exception e){e.printStackTrace ();} Ds%9cp*6  
} ~Cjz29|gp  
} "w}-?:# j  
X+=-f^)&  
Nls83 W  
//打印回应的头信息 8YuJ8KC  
public void logResponseHead(HttpURLConnection con) -PNi^ K_  
{ )y9;OA  
for(int i=1;;i++) Y/. AUN Z  
{ &+mV7o  
String header=con.getHeaderFieldKey(i); A /q2g7My  
if(header!=null) ifXW  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  !M  
Utility.log(header+" : "+con.getHeaderField(header)); KcC!N{  
else %'Zc2h&z  
break; , N53Iic  
} &4,WG  
} ?Bo?JMV  
OF c\fW#  
ojHhT\M`  
public void splitterStop() !Y ( apVQ  
{ t#C,VwMe[  
bStop = true; >\V6+$cNp  
} ]UDd :2yt  
q[7CPE0n  
9<yAQ?7 L  
} \+-zRR0  
+'%@!  
bS>R5*Zp  
/* HF"Eys  
**FileAccess.java ~12_D'8D[  
*//文件访问(定位,写) "`pNH'   
package NetFox; S]}}A  
import java.io.*; n.*3,4.]  
\tY"BC4.  
{Fbg]'FQ  
public class FileAccessI implements Serializable{ u*2fP]n  
kw*)/$5]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 P0^c?s"I  
RandomAccessFile oSavedFile; 8{dEpV*  
long nPos; /Rj#sxtdw  
}g~g50ci  
3y99O $EAc  
public FileAccessI() throws IOException KU-'+k2s;p  
{ 11@]d ]v ,  
this("",0); Q]@c&*_|  
} Fh K&@@_  
z v>Oh#  
>OV<_(S4  
public FileAccessI(String sName,long nPos) throws IOException nX|Q~x]  
{ H@GE)I>^@  
oSavedFile = new RandomAccessFile(sName,"rw"); NUCiY\td  
this.nPos = nPos; )l&D]3$6K  
oSavedFile.seek(nPos); #%:c0=  
} 2-~|Z=eGW  
F/>*If s  
|( G2K'Ab  
public synchronized int write(byte[] b,int nStart,int nLen) vA=Z=8  
{ yGxv?%%2  
int n = -1; (&jW}1D  
try{ kY"KD22a  
oSavedFile.write(b,nStart,nLen); @Br {!#Wf  
n = nLen; #)o7"PW:  
} #uSK#>H_!  
catch(IOException e) .wmnnvtl,  
{ wd[eJcQ,  
e.printStackTrace (); ks*Y9D*=  
} q*, Q5  
uRE*%d>  
)P?IqSEA%  
return n; re^Hc(8M  
} !^e =P%S  
'cV?i&;  
yhpz5[AuO  
} rEdY>\'  
/.Fj.6U5  
_%~$'Hy  
/* 54{q.I@n  
**SiteInfoBean.java +`B'r '  
*/ $IVwA  
package NetFox; "X04mQn15  
8Hi!kc;f6>  
^rL_C}YBj-  
public class SiteInfoBean { /)EY2Y'  
EF#QH _X  
87V1#U^  
private String sSiteURL; //Site's URL UL( lf}M  
private String sFilePath; //Saved File's Path {hQ6K)s  
private String sFileName; //Saved File's Name I9Eu',  
private int nSplitter; //Count of Splited Downloading File Kc #|Z  
ecj7BT[mLI  
Dzl;-]S  
public SiteInfoBean() N2ied^* 0  
{//nSplitter的缺省值为5 MV0Lq:# N  
//default value of nSplitter is 5 +pf5\#l?  
this("","","",5); 6?qDdVR~]  
} x({H{'9?  
9M a0^_  
rv>^TR*,!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) BQ/PGY>  
{ gd7^3q[$h  
sSiteURL= sURL; hIYTe  
sFilePath = sPath; }^-<k0A4?  
sFileName = sName; 8 Ti G3  
this.nSplitter = nSpiltter; P:C2G(V1AR  
w8Vw1wW  
bc I']WgB-  
} Hp Vjee  
t\4[``t  
D\1k.tI  
public String getSSiteURL() >\2:\wI  
{ kL>d"w  
return sSiteURL; @F~LW6K  
} x;LzG t:w  
?+0GfIV  
At6qtoPRA  
public void setSSiteURL(String value) >?lOE -}^  
{ qQ0C?  
sSiteURL = value; uuNR?1fS  
} kW@,$_cK  
w%y\dIeI'  
?F7o!B  
public String getSFilePath() C/=XuKE-t  
{ yClx` S(  
return sFilePath; +Qxu$#  
} 71fk.16  
 d$W  
-%CoWcGP  
public void setSFilePath(String value) (:pq77  
{ 5fJ[}~  
sFilePath = value; EH*o"N`!r  
} UPiW73Nu  
,=QM#l]  
b'YE9E  
public String getSFileName() b:J(b?  
{ MZ> 6o5K|  
return sFileName; p(F" /  
} /9pM>Cd*Z  
$((6=39s  
(ljF{)Ml+=  
public void setSFileName(String value) ] )DX%$f  
{ _>m-AI4^  
sFileName = value; 44ed79ly0)  
} q.#[TI ^  
ccFn.($p?,  
.w?(NZ2~  
public int getNSplitter() @}-r&/#  
{ ->^~KVh&  
return nSplitter; N|g;W  
} )~J>X{hy  
kq=V4-a[  
FQz?3w&ia  
public void setNSplitter(int nCount) a:, y Z  
{ ;`YkMS`=W  
nSplitter = nCount; ;%C'FV e]  
} v``-F(i$  
} )E#2J$TD  
=sJ _yq0#R  
[, RI-#n  
/* }[+!$#  
**Utility.java j@gMb iu  
*/ >'uU)Y {  
package NetFox; I04jjr:<  
cF)/^5Z  
B+d<F[ |  
public class Utility { F>je4S;  
|{r$jZeE  
j%u-dr  
public Utility() N,dT3we  
{ M 3 '$[  
f/,>%j=Ms  
_@mRb^  
} l>gI&1)%  
xT&(n/  
//线程睡眠 2T@GA 1G  
public static void sleep(int nSecond) kd`0E-QU  
{ D_mL,w  
try{ 7?8wyk|x  
Thread.sleep(nSecond); {5r0v#;  
} >T2LEW  
catch(Exception e) E/&Rb*3  
{ u%/fx~t$  
e.printStackTrace (); H=*5ASc  
} im} ?rY  
} {Gq*e/  
<ljI;xE  
//日志 %CwL:.|  
public static void log(String sMsg) n% 'tKU\q  
{ Pi,QHb`>  
System.err.println(sMsg); ml0.$z  
} v2r&('pV  
UJfT!==U  
>d"3<S ; b  
public static void log(int sMsg) n\Fp[9+Z\  
{ &AVpLf:?  
System.err.println(sMsg); {t"+ 3zy'  
} Oa;X +  
} EN{]Qb06A  
!Cgx.   
" 96yp4v@  
/* %*aJLn+]_R  
**TestMethod.java ^, l_{  
*/ ?Xdak|?i  
package NetFox; 9Zry]$0~R  
NN0$}acp  
Uoya3#4 G  
public class TestMethod { [ EFMu;q  
iovfo2!hD  
09A X-JP  
public TestMethod() "mL++>ZSQ  
{ ///xx/weblogic60b2_win.exe c4&'D;=  
try{ 73{'k K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Q9}dHIe1E  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `Y-|H;z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $aHAv/&(5  
fileFetch.start(); I;5R2" 3  
} 8[r9HC  
catch(Exception e){e.printStackTrace ();} )jWO P,|  
(,^*So/  
>hBxY]< \  
} x!\ONF5$  
oH0X<'  
43?^7_l-  
public static void main(String[] args) _&K  
{ |KB0P@=a  
new TestMethod(); :m86 hBE.  
} D=:04V}2+  
} !D!~ ^\  
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