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http断点续传简单实现(java)

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/* 7HY8 F5Brx  
**SiteFileFetch.java ?b'(39fj  
*/ ;&f(7 Q+T_  
package NetFox; -5]lHw}  
import java.io.*; %.wR@9?  
import java.net.*; KHx;r@{<  
5} <OB-9  
E(_k#X  
public class SiteFileFetch extends Thread { Rq e|7/As  
ZZwIB3sNhf  
zBwqIJfM  
SiteInfoBean siteInfoBean = null; //文件信息Bean u|.|dv'mbp  
long[] nStartPos; //开始位置 ,)!%^ ~v  
long[] nEndPos; //结束位置 ntB#2S  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +4Wl  
long nFileLength; //文件长度 #H4<8B  
boolean bFirst = true; //是否第一次取文件 a5O$he  
boolean bStop = false; //停止标志 ]bmf}&  
File tmpFile; //文件下载的临时信息 f%1\1_^g  
DataOutputStream output; //输出到文件的输出流 7fzH(H  
!FyO5`v  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) K^[m--  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~;pP@DA  
{ ahZ@4v  
siteInfoBean = bean; lKU{jWA  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6vxRam6[??  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); WlY\R>x#  
if(tmpFile.exists ()) n9 FA` e  
{ 7\$b%A  
bFirst = false; \ K}KnJ  
read_nPos(); -|s% 5p|  
} {~R?f$}""j  
else ])bgUH  
{ #Tag"b`  
nStartPos = new long[bean.getNSplitter()]; $FIJI^Kd7  
nEndPos = new long[bean.getNSplitter()]; >Di`zw~  
} *SI,K)BP  
_*[vKS A&  
;{&4jcV*  
Y*A y=@z=y  
} ",[/pb  
g`C"t3~%S  
xC= $ym]  
public void run() i$}G[v<4  
{ )+hJi/g  
//获得文件长度 _8-1wx  
//分割文件 Er8F_,M+  
//实例FileSplitterFetch q o-|.I  
//启动FileSplitterFetch线程 'qo(GGC M  
//等待子线程返回 Xt:j~cVA  
try{ <;>k[P'  
if(bFirst) $Jn.rX0}$  
{  xiQc\k$  
nFileLength = getFileSize(); "?<`]WG\  
if(nFileLength == -1) xO %yjG=  
{ >b#CR/^z  
System.err.println("File Length is not known!"); X}h}3+V  
} fpjFO&ML  
else if(nFileLength == -2) .wWf#bB  
{ 8@rF~^-_  
System.err.println("File is not access!"); .#a7?LUH  
} OI:=>Bk  
else 0$Zh4Y  
{ FEopNDy@y  
for(int i=0;i<nStartPos.length;i++) NU{eoqaT  
{ 0pB'^Q{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P@n rcgM.  
} 3BLH d<  
for(int i=0;i<nEndPos.length-1;i++) t4~?m{  
{ 2v4&'C  
nEndPos = nStartPos[i+1]; B VH)!]m0  
} qX6zk0I a  
nEndPos[nEndPos.length-1] = nFileLength; VC Ay~,  
} x 0vW9*&  
} i!JSEQ_8  
'&gUAt  
j\Fbi3H  
//启动子线程 $(OL#>9Ly  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G%i&C)jZ  
for(int i=0;i<nStartPos.length;i++) ~"wnlG-:  
{ @^-f +o  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }095U(@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ov\%*z2=  
nStartPos,nEndPos,i); h]|2b0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i1b3>H*3  
fileSplitterFetch.start(); ,y/m5-D!  
} &@2`_%QtA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), **6X9ZIX[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :,/ \E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X C390t  
nEndPos = " + nFileLength); y|9 LtQ  
// fileSplitterFetch[nPos.length-1].start(); <3=k  
JE$ $6X  
LA6Ik_-F  
//等待子线程结束 rXe+#`m2  
//int count = 0; I3l1 _  
//是否结束while循环 bOV]!)o  
boolean breakWhile = false; Nii5},  
abEdZ)$  
z!~{3M  
while(!bStop) }y*rO(cu7G  
{ ?ia O6HD  
write_nPos(); N a.e1A&?j  
Utility.sleep(500); uIJ zz4  
breakWhile = true; &mA{_|>  
1ahb:Mjv  
[{ A5BE -  
for(int i=0;i<nStartPos.length;i++) IY2f$YV  
{ 5hAs/i9_  
if(!fileSplitterFetch.bDownOver) :ZM=P3QZ  
{ @Hp=xC9V  
breakWhile = false; + J}h  
break; wG22ffaki  
} oOQ0f |MGp  
} ]ddL'>$c$  
if(breakWhile) L'>0E(D  
break; 0J= $ A  
BT5~MYBl  
*vzj(HGO  
//count++; k.H4Mf(4  
//if(count>4) C\ cZ  
// siteStop(); 5Ak>/QF9  
} ]}_Ohe]X  
gGbqXG^  
/"1[qT\F  
System.err.println("文件下载结束!"); OnE~0+  
} |X~vsM0  
catch(Exception e){e.printStackTrace ();} 2QIo|$  
} VZA>ErB  
FvBnmYn W  
N$8"X-na?  
//获得文件长度 .Na'yS `J  
public long getFileSize() 7b kh")^  
{ j2%#xZ{33  
int nFileLength = -1; mi sPJO&QD  
try{ DJRr  
URL url = new URL(siteInfoBean.getSSiteURL()); #)KQ-x,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P?iQ{x}w~  
httpConnection.setRequestProperty("User-Agent","NetFox"); 93Qx+oK]  
(i^<er q  
k,[[ CZ0j  
int responseCode=httpConnection.getResponseCode(); FWyfFCK  
if(responseCode>=400) #~qY%X  
{ 7)Bizlf  
processErrorCode(responseCode); I{u+=0^Y  
return -2; //-2 represent access is error o7:"Sl2AD  
} ^c>ROpic  
AiV1 vD`  
X,+N/ nku  
String sHeader; : DBJ2n  
%TQ5#{Y  
{=E,.%8  
for(int i=1;;i++) ]LSlo593  
{ 0 9*?'^s4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); mC`U"rlK~  
//Utility.log(in.readLine()); y@]:7  
sHeader=httpConnection.getHeaderFieldKey(i); G\S_e7$ /  
if(sHeader!=null) 4p`z%U~=u  
{ t-J\j"~%+  
if(sHeader.equals("Content-Length")) ]B-3Lh  
{ 8d\/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Oj.xJ(uX+v  
break; TbhsOf!  
} t3aDDu  
} L>2gx$f  
else xO'xZ%cUI  
break; j|(bdTZY:  
} `[.4SIah  
} G%fNGQwT  
catch(IOException e){e.printStackTrace ();} K db:Q0B  
catch(Exception e){e.printStackTrace ();} ^g N?Io  
_ ~E_#cNn  
0Y ld!L  
Utility.log(nFileLength); ltG|#(  
k|_LF[*Z  
^9*Jz{e  
return nFileLength; ?rububDT{  
} nA XWbavY  
\EeK<)4:  
mF] 8  
//保存下载信息(文件指针位置) ~C;gEE-  
private void write_nPos() 2lBfc  
{ Y>'t)PK  
try{ iJ~e8l0CA  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Zk 9i}H  
output.writeInt(nStartPos.length); x?-kt.M  
for(int i=0;i<nStartPos.length;i++) .&c!k1kH  
{ DP7B X^e  
// output.writeLong(nPos); Pt %EyFG  
output.writeLong(fileSplitterFetch.nStartPos); BYsQu.N  
output.writeLong(fileSplitterFetch.nEndPos); 6SmawPPP  
} uze5u\  
output.close(); Je;HAhL  
} g 2&P  
catch(IOException e){e.printStackTrace ();} CjlA"_!%E  
catch(Exception e){e.printStackTrace ();} *Mr'/qp,  
} 2o9IP>#u  
G_n~1?  
}h`ddo  
//读取保存的下载信息(文件指针位置) bjGQ04da  
private void read_nPos() 1 gx(L*y,  
{ I r;Z+}4>Y  
try{ 7W\aX*]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +h? z7ZY^  
int nCount = input.readInt(); _f~m&="T!  
nStartPos = new long[nCount]; e.pq6D5  
nEndPos = new long[nCount]; sBm/9vu  
for(int i=0;i<nStartPos.length;i++) #_[W*-|L  
{ RiM!LX  
nStartPos = input.readLong(); 8qQrJFm|3*  
nEndPos = input.readLong(); +%RB&:K7,  
} q|7$@H^*  
input.close(); O_ /|Wx  
} ~l>2NY  
catch(IOException e){e.printStackTrace ();} ,*'aH z  
catch(Exception e){e.printStackTrace ();} SI@Yct]<g  
} 9q f=P3  
- -H%FYF`  
:~+m9r  
private void processErrorCode(int nErrorCode) qz/d6-0"  
{ K yFR;.F-  
System.err.println("Error Code : " + nErrorCode); B< BS>(Nr>  
} 14;lB.$p  
Wc- 8j2M  
XP!7@:  
//停止文件下载 Pi:=0,"XOp  
public void siteStop() xSoXf0zq:  
{ `tZ`a  
bStop = true; 0ud>oh4WPR  
for(int i=0;i<nStartPos.length;i++) H@hHEzO  
fileSplitterFetch.splitterStop(); Qp]-4%^Vz  
Sk&l8"  
b!xm=U  
} # ^oF^!  
} (qXl=e8  
//负责部分文件的抓取 eMV@er|  
**FileSplitterFetch.java 8 |iMD1  
*/ sz+Uq]Mn  
package NetFox; P_3U4J  
G`r*)pdm  
QHuh=7u)  
import java.io.*; )!(etB=`y  
import java.net.*; JqmKD4p  
/Jci1o  
_ 0Ced&i  
public class FileSplitterFetch extends Thread { 0ge^p O\Z  
-6u#:pVpU  
=C.WM*='  
String sURL; //File URL =3Hv  
long nStartPos; //File Snippet Start Position [e+$jsPl  
long nEndPos; //File Snippet End Position Pb-Ft =  
int nThreadID; //Thread's ID v<U +&D{  
boolean bDownOver = false; //Downing is over M~&X?/8  
boolean bStop = false; //Stop identical nzK"eNDN.  
FileAccessI fileAccessI = null; //File Access interface <<[hZ$.  
'U'#_mYG  
wam- =3W  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 86,$ I+  
{ -P3;7_}]:h  
this.sURL = sURL; ,dIo\Lm  
this.nStartPos = nStart; "G`8>1tO_  
this.nEndPos = nEnd; .}l&lj@#  
nThreadID = id; y3vm+tJc{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^9C9[$Q  
} {<3>^ o|"  
;Jrk#7  
Yi+~}YP.E(  
public void run() kGX;x}q  
{ ]\t+zF>&Y  
while(nStartPos < nEndPos && !bStop) {Q la4U  
{ cWA$O*A  
E@F:U*A6%  
xz$S5tgDQK  
try{ c_r&)8  
URL url = new URL(sURL); /Aq):T T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2dF:;k k  
httpConnection.setRequestProperty("User-Agent","NetFox"); N%.Dj H  
String sProperty = "bytes="+nStartPos+"-"; 5{&<X.jv  
httpConnection.setRequestProperty("RANGE",sProperty); TGJ\f  
Utility.log(sProperty); zsx12b^w  
WrGz`  
sR1 &2hB  
InputStream input = httpConnection.getInputStream(); br9`77J8  
//logResponseHead(httpConnection); aab?hR  
uF=xo`=|  
yNb :zoT  
byte[] b = new byte[1024]; %aszZP  
int nRead; k5@_8Rc  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dIR6dI   
{ #`0iN+qh  
nStartPos += fileAccessI.write(b,0,nRead); 7o4 vf~  
//if(nThreadID == 1) rGe^$!QB  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^{W#ut>IN  
} :tA|g  
'0xJp|[xVP  
(Q$]X5L  
Utility.log("Thread " + nThreadID + " is over!"); } bs2Rxkh  
bDownOver = true; cCjpQ  
//nPos = fileAccessI.write (b,0,nRead); A<&:-Zz  
} D?w-uR%Y  
catch(Exception e){e.printStackTrace ();} drQioH-  
} V!S B9t`E  
} (1vmtg.O  
CKTD27})  
X; gN[  
//打印回应的头信息 a'v%bL;H~  
public void logResponseHead(HttpURLConnection con) ):_x  
{ DvuL1Me Ko  
for(int i=1;;i++) zq5_&AeW  
{ )^&)f!f  
String header=con.getHeaderFieldKey(i); B`4[@$  
if(header!=null) %-4e8d74/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); sKX%<n$  
Utility.log(header+" : "+con.getHeaderField(header)); S"=o U}'|  
else e XU;UO^  
break; DT=!  
} YJ5;a\QxN  
} ~%Ws"1  
uxto:6),P<  
3\,TI`^C  
public void splitterStop() Xm`K@hJ@  
{ JHf}LZu  
bStop = true; C%P"Ds=w0N  
} hfvs' .  
e;=G|E  
b* 6c.  
} NRKAEf_#w  
;D/'7f7.}  
t3/!esay  
/* omV.Qb'NS  
**FileAccess.java Dz&4za+{  
*//文件访问(定位,写) b)u9#%Q  
package NetFox; d]e`t"Aj  
import java.io.*;  <C4^Vem  
X/1Z9 a+W  
^}8_tZs8\  
public class FileAccessI implements Serializable{ na FZ<'t>&  
Q9[dUdQm  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 utwh"E&W  
RandomAccessFile oSavedFile; <,0& Ox  
long nPos; tS2lex%  
eT+MN`  
5b B[o6+  
public FileAccessI() throws IOException -o#0Yt}3  
{ >?e*;f$VdJ  
this("",0); e_6 i896  
} |y%pP/;&!  
0;TMwE  
sZ'3PNpCP  
public FileAccessI(String sName,long nPos) throws IOException /]xd[^  
{ j.C C.[$g  
oSavedFile = new RandomAccessFile(sName,"rw"); Yb =8\<;  
this.nPos = nPos; CSU>nIE0  
oSavedFile.seek(nPos); :B- ,*@EU  
} {uj9fE,)  
j )F~C8*  
%h%r6EB1F  
public synchronized int write(byte[] b,int nStart,int nLen) Ro:-u7q  
{ S0=BfkHi.  
int n = -1; XB;;OP12  
try{ 73xI8  
oSavedFile.write(b,nStart,nLen); l}AB):<Z  
n = nLen; ^:-%tpB#!  
} Gz*U?R-T  
catch(IOException e) dm$:xE":  
{ kd \G>  
e.printStackTrace (); .yWdlq##  
} Fr%KO)s2  
udc9$uO  
`%ymg8^  
return n; 0/KNXz  
} &U 'Ds!  
!#iP)"O  
hG us!p"lw  
} <E\BKC%M  
w\t{'  
<1jiU%!w  
/* 2N,*S   
**SiteInfoBean.java 0\Oeo8<7)~  
*/ \+Cp<Hv+  
package NetFox; xD lC]loi7  
:,VyOmf  
K->p&6s  
public class SiteInfoBean { hcaH   
%)aDh }  
E 0oJ|My  
private String sSiteURL; //Site's URL ^$#Q_Y|  
private String sFilePath; //Saved File's Path ac&tpvij  
private String sFileName; //Saved File's Name 2=3iA09px  
private int nSplitter; //Count of Splited Downloading File L:^'cl} G  
Vk_L*lcN  
(~#PzE :  
public SiteInfoBean() zu|pL`X  
{//nSplitter的缺省值为5 sU}e78mh  
//default value of nSplitter is 5 \R#XSW,  
this("","","",5); q5RLIstQ\  
} etDB|(,z  
(8ymQ!aY  
|n &6z  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -0\$JAyrx  
{ 7I.[1V`  
sSiteURL= sURL; yWK[@;S]%  
sFilePath = sPath; IaF79}^  
sFileName = sName; d~_OWCg`  
this.nSplitter = nSpiltter; l/I W"A  
iCEX|Tj;  
da<1,hF  
} FP\[7?ZLn  
?QMs<  
A=3 U4L  
public String getSSiteURL() @LmUCP~  
{ QTyl=z7  
return sSiteURL;  :D/R  
} #e0+;kBh  
jf2E{48P  
3~S~)quwP  
public void setSSiteURL(String value) O0I/^  
{ ,#m\W8j  
sSiteURL = value; x-W0 h  
} C'$U1%: j  
CRf^6k_;(  
Cv=0&S.  
public String getSFilePath() lubS{3<  
{ 7)]G"m{  
return sFilePath; A6Qi^TI  
} 4@Qq5kpk*  
$H 9xM  
}Ag2c; aaq  
public void setSFilePath(String value) lwB!ti  
{ s-DtkO  
sFilePath = value; l;C_A;y\  
} &S{F"z  
oc?VAF  
&KB{,:)?  
public String getSFileName() U9q*zP_jV  
{ c*W$wr  
return sFileName; 5u8Sxfm",  
} }qg!Um0  
Tld{b  
>w'6ZDA*X  
public void setSFileName(String value) 0'<S7?~|  
{ S,v`rmI  
sFileName = value; BZBsE :(F  
} WV% KoM,%  
g?`J,*y  
I F@M  
public int getNSplitter() Nf~<xK  
{ -Z@ p   
return nSplitter; oa4}GNH  
} r5"/EMieh  
E0|aI4S4  
83 n: h08  
public void setNSplitter(int nCount) N$+"zJmw&  
{ ;CrA  
nSplitter = nCount; A4^+p0@  
} 68SM br  
} `l}-S |a  
L9.#/%I\  
C+mU_g>  
/* f0F$*"#G  
**Utility.java F, "x~C  
*/ DjKjEZHgM  
package NetFox; Z*)<E)  
y\[=#g1(@  
fS ~.K9  
public class Utility { 2Ar<(v$  
0v_8YsZ!`$  
g DhwJks  
public Utility() A"'MRYT`  
{ { nV zN(  
>&VL2xLy  
%L/=heBBd  
} (pmo[2kg  
6~}H3rvO}  
//线程睡眠 EDo (  
public static void sleep(int nSecond) |h7v}Y  
{ H07j&  
try{ |}`5< a!6U  
Thread.sleep(nSecond); (TE2t7ab|M  
} =T-w.}27O  
catch(Exception e) u!i5Q  
{ JvDsr0]\#  
e.printStackTrace (); WdT|xf.Q&  
} _(hwU>.  
} vf2K2\fn  
|(S W  
//日志 7'|PHQ?S  
public static void log(String sMsg) j#&  
{ >=V+X"\Z  
System.err.println(sMsg); ZwMw g t  
} <-F"&LI{<  
pV7Gh`<y  
wGvgMZ]?'  
public static void log(int sMsg) AVp [gr  
{ wLtTC4D  
System.err.println(sMsg); H[D/Sz5`  
} ]c)SVn$6  
} BGX@n#:  
}]I?vyQ#V  
$<v_Vm?6d  
/* K288&D|1WU  
**TestMethod.java :~(im_r  
*/ !A!\S/x4  
package NetFox; R%%`wmG)"  
5)UmA8"zVB  
CC\z_C*P-p  
public class TestMethod { K\b O[J  
+HX'AC  
+]-KzDsr"V  
public TestMethod() 9QMn%8=j  
{ ///xx/weblogic60b2_win.exe 2An`{')  
try{ Bt,Xe~$z-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); R~~rqvLm  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); o!~bR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); to3J@:V8e  
fileFetch.start(); >|?T|  
} [R4x[36Zp  
catch(Exception e){e.printStackTrace ();} Wv"tAseu  
kre&J  
$1+K}tP  
} 5F"?]'*/  
Z+"&{g  
vi8~j  
public static void main(String[] args) ^>Y%L(>  
{ &r%*_pX  
new TestMethod(); ^{:jY, ?]  
} iIE(zw)H  
} <^U(ya  
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