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http断点续传简单实现(java)

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/* o}!PQ#`M  
**SiteFileFetch.java Lr<cMK<  
*/ 4R*,VR.K  
package NetFox; #b`k e/P  
import java.io.*; fZ. ONq  
import java.net.*; *] (iS  
l^qI, M  
~m |BC*)  
public class SiteFileFetch extends Thread { nrb Ok4Dz  
M_8{]uo  
{8OCXus3m  
SiteInfoBean siteInfoBean = null; //文件信息Bean M}Sv8D]I  
long[] nStartPos; //开始位置 AR=]=8  
long[] nEndPos; //结束位置 kP"9&R`E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ceV}WN19l  
long nFileLength; //文件长度 VE24ToI?W"  
boolean bFirst = true; //是否第一次取文件 5m*,8]!-  
boolean bStop = false; //停止标志 =Uh$&m  
File tmpFile; //文件下载的临时信息 ^s=8!=A(  
DataOutputStream output; //输出到文件的输出流 RpF&\x>  
Ned."e  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) KSvE~h[#+  
public SiteFileFetch(SiteInfoBean bean) throws IOException ys~x $  
{ 7Wno':w8  
siteInfoBean = bean; pUTr!fR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); OCUr{Nh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &vJH$R  
if(tmpFile.exists ()) :>*7=q=  
{ r,udO,Yi=c  
bFirst = false; ;fJ.8C  
read_nPos(); TN.rrop`#g  
} /\Ef%@  
else Fp:'M X  
{ @VBcJ{e,  
nStartPos = new long[bean.getNSplitter()]; "#]$r  
nEndPos = new long[bean.getNSplitter()]; :0ep( <|;  
} : 'c&,oLY  
xmG<]WF>E  
G#CXs:1pd+  
N$DkX)Z  
} *Uh!>Iv;  
d@^ZSy>L2  
u"8yK5!  
public void run() Q@niNDaW2  
{ zTp"AuNHN  
//获得文件长度 w@ pPcZ>z/  
//分割文件 n ;Ei\\p!  
//实例FileSplitterFetch U17d>]ka  
//启动FileSplitterFetch线程 yr6V3],Tp  
//等待子线程返回 7"##]m.  
try{ ?CZd Ol  
if(bFirst) H[gWGbPq7  
{ ?(PKeq6  
nFileLength = getFileSize(); g\U-VZ6;p  
if(nFileLength == -1) pI[uUu7O  
{ phK/   
System.err.println("File Length is not known!"); |zU-KGO&  
} XkqCZHYkS  
else if(nFileLength == -2) I*&8^ r:A  
{ #QPjk R|\  
System.err.println("File is not access!"); qLCR] _*  
} @,}UWU  
else C+]I@Go'Tk  
{ -} +[  
for(int i=0;i<nStartPos.length;i++) S3#>9k;p  
{ XG?8s &  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9ati`-y2  
} ~[ F`"  
for(int i=0;i<nEndPos.length-1;i++) )1z@  
{ pw#-_  
nEndPos = nStartPos[i+1]; @L`jk+Y0vF  
} K'xV;r7Nt  
nEndPos[nEndPos.length-1] = nFileLength; S @Y39  
} 9$Y=orpWxr  
} fOHxtHM  
5N]"~w*  
pdMc}=K  
//启动子线程 @d_M@\r=j  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; KXrjqqXs  
for(int i=0;i<nStartPos.length;i++) Z,=1buSz_  
{ k!^{eOM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YQ} o?Q$z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Fcx&hj1gQ  
nStartPos,nEndPos,i); .X&9Q9T=#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^pS~Z~[d/  
fileSplitterFetch.start(); jo7\`#(Q  
} t:S+%u U  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LP-o8c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =AT."$r>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", So6x"1B  
nEndPos = " + nFileLength); IgzQr >  
// fileSplitterFetch[nPos.length-1].start(); 3R/bz0 V>  
'R)Tn!6  
NHt\ U9l'  
//等待子线程结束 rjP/l6 ~'  
//int count = 0; 0_/[k*Re  
//是否结束while循环 lYIH/:T  
boolean breakWhile = false; `XKLU  
iCoX& "lb  
"tZe>>I  
while(!bStop) e.%nRhSs3  
{ ^Pf WG*  
write_nPos(); y7{?Ip4[  
Utility.sleep(500); IBGrt^$M  
breakWhile = true; "MsIjSu  
@iiT<  
_aphkeqd  
for(int i=0;i<nStartPos.length;i++) xk5 ]^yDp  
{ #Y! a6h+  
if(!fileSplitterFetch.bDownOver) VUc%4U{Cti  
{ ("@!>|H  
breakWhile = false; } \f0 A-  
break; Mt$ *a  
} #Z#-Ht  
} x^ni1=kU  
if(breakWhile)  }ZI7J  
break; V9vTsmo(  
Iv *<L a  
\['Cj*ek  
//count++; nTas~~Q  
//if(count>4) #_1`)VS  
// siteStop(); =I<R!ZSN  
} aXVFc5C\  
(:_$5&i7  
t1".0  
System.err.println("文件下载结束!"); 9$t( &z=  
} ?< />Z)  
catch(Exception e){e.printStackTrace ();} 3Vwh|1?  
} -=="<0c  
}k0_5S  
J,hCvm  
//获得文件长度 mw!F{pw  
public long getFileSize() PCvWS.{  
{ 29rX%09T]  
int nFileLength = -1; _$'ashF  
try{ /z!%d%"  
URL url = new URL(siteInfoBean.getSSiteURL()); }C:r 9? T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E./2jCwI(Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); H|*m$| $,  
[ 3Gf2_  
a#4?cEy  
int responseCode=httpConnection.getResponseCode(); bOB \--:]  
if(responseCode>=400) uH]OEz\H'  
{ _w{Qtj~s|  
processErrorCode(responseCode); !VJoM,b8  
return -2; //-2 represent access is error Wzh`or  
} 1x)J[fyId  
.8R@2c`}Cs  
D- c4EV  
String sHeader; w(/S?d  
AdEMa}u 6  
2iOV/=+  
for(int i=1;;i++) YVU7wW,1  
{ = &]L00u.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^c<Ve'-  
//Utility.log(in.readLine()); j^'go&p  
sHeader=httpConnection.getHeaderFieldKey(i); 8Wx=p#_  
if(sHeader!=null) %;_MGae  
{ UpG~[u)%@  
if(sHeader.equals("Content-Length")) \<' ?8ri#  
{ L#J1b!D&<6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); fl(wV.Je|  
break; .3;;;K9a~]  
} uph(V  
} *T/']t  
else #4PN"o@  
break; X, n:,'  
} 6'/ #+,d'  
} _U(  
catch(IOException e){e.printStackTrace ();} y0#2m6u  
catch(Exception e){e.printStackTrace ();} [6fQ7uFMM8  
=euni}7a  
+rd+0 `}C  
Utility.log(nFileLength); V&5wRz+`W  
=  [E  
8=l%5r^cq  
return nFileLength; cr3^6HB  
} ,prf;|e?  
u_enqC3  
b;n[mk  
//保存下载信息(文件指针位置) 2ESo2  
private void write_nPos() ]DcFySyv  
{ r; {.%s7  
try{ RP"kC4~1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); aOp\91  
output.writeInt(nStartPos.length); wT@og|M  
for(int i=0;i<nStartPos.length;i++) #mF"1QW  
{ K-4PI+qQ\  
// output.writeLong(nPos); _b 0& !l<  
output.writeLong(fileSplitterFetch.nStartPos); n S=W1zf  
output.writeLong(fileSplitterFetch.nEndPos); HfVZ~PP  
} +%'(!A?*`  
output.close(); _/|\aqF.  
} q m}@!z^  
catch(IOException e){e.printStackTrace ();} d0D] Q  
catch(Exception e){e.printStackTrace ();} ^!d3=}:0  
} vN:Ng  
>6T8^Nt  
)GpK@R]{  
//读取保存的下载信息(文件指针位置) d=(mw_-?  
private void read_nPos() 3BI1fXT4=j  
{ s!J9|]o  
try{ R_C)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _f83-':W6  
int nCount = input.readInt(); ^('wy};  
nStartPos = new long[nCount]; (=0.inZ  
nEndPos = new long[nCount]; XSR 4iu  
for(int i=0;i<nStartPos.length;i++) ;l+Leex  
{ # d  
nStartPos = input.readLong(); .Mbz3;i0  
nEndPos = input.readLong(); l#o ~W`  
} .A|udZ,  
input.close(); S[gx{Bxiw  
} 7#XzrT]  
catch(IOException e){e.printStackTrace ();} qGo.WZ$  
catch(Exception e){e.printStackTrace ();} IxU/?Zm  
} 1zv'.uu.,  
:;}P*T*PU  
?}oFg#m-<L  
private void processErrorCode(int nErrorCode) `?]k{ l1R  
{ la!~\wpa  
System.err.println("Error Code : " + nErrorCode); dPlV>IM$z  
} T)/eeZ$  
FrS]|=LJhX  
Ui~>SN>s  
//停止文件下载 @"A4$`Xi3  
public void siteStop() oR'm2d^  
{ b6bHTH0  
bStop = true; (QEG4&9  
for(int i=0;i<nStartPos.length;i++) +7Gwg  
fileSplitterFetch.splitterStop(); )nkY_' BV  
L *wYx|  
J1k>07}|  
} K- v#.e4  
} D*jM1w_`  
//负责部分文件的抓取 t.<i:#rj>l  
**FileSplitterFetch.java 4?kcv59  
*/ 9[4xFE?|  
package NetFox; Wr 4,YQM  
XFl 6M~ c  
>MZ/|`[M  
import java.io.*; ="+#W6bZT  
import java.net.*; z/-=%g >HA  
d]9z@Pd   
2/?|&[  
public class FileSplitterFetch extends Thread { ch]IzdD  
#a#F,ZT  
KlEpzJ98  
String sURL; //File URL 7CysfBF0g  
long nStartPos; //File Snippet Start Position -7ep{p-  
long nEndPos; //File Snippet End Position sJZ iI}Xc  
int nThreadID; //Thread's ID >4TO=i  
boolean bDownOver = false; //Downing is over i-1op> Y  
boolean bStop = false; //Stop identical `5*}p#G  
FileAccessI fileAccessI = null; //File Access interface sHj/;  
3o*YzwRt  
- ).C  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )0`C@um  
{ hN_]6,<\  
this.sURL = sURL; X|dlt{Gf   
this.nStartPos = nStart; yi[x}ffdE  
this.nEndPos = nEnd; Rq-ZL{LR7  
nThreadID = id; -"x$ZnHU  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E .h*g8bXe  
} W/N7vAx X  
5xiEPh  
).O)p9  
public void run() KNl$3nX  
{ 0GLM(JmK  
while(nStartPos < nEndPos && !bStop) ~%oR[B7=|  
{ Eci\a]  
@7 }W=HB  
>P(.:_ ^p  
try{ kh<2BOV  
URL url = new URL(sURL); F4QVAOM]U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :jf3HG  
httpConnection.setRequestProperty("User-Agent","NetFox"); &{:-]g\  
String sProperty = "bytes="+nStartPos+"-";  " bG2:  
httpConnection.setRequestProperty("RANGE",sProperty); u8^lB7!e/  
Utility.log(sProperty); `[A];]  
 *CMx-_  
BT$_@%ea&  
InputStream input = httpConnection.getInputStream(); )J |6-C  
//logResponseHead(httpConnection); TeQV?ZQ#}  
rv;3~'V  
:RYTL'hes  
byte[] b = new byte[1024]; x`s>*^  
int nRead; 7<4qQ.deE  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) XW/o<[91  
{ crCJrN=  
nStartPos += fileAccessI.write(b,0,nRead); \8tsDG(1 '  
//if(nThreadID == 1) #yen8SskB  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4-w{BZuS  
} UiWg<_<t  
=4!mAo}  
$G>.\t  
Utility.log("Thread " + nThreadID + " is over!"); ]:;&1h3'7  
bDownOver = true; }H4RR}g  
//nPos = fileAccessI.write (b,0,nRead); %O<BfIZ  
} Cx"sw }  
catch(Exception e){e.printStackTrace ();} xno\s.H%]  
} =1! 'QUc  
} }Jw,>}  
]n~V!hl?A  
}JfjX '  
//打印回应的头信息 ?2a$*(  
public void logResponseHead(HttpURLConnection con) k)u[0}   
{ =Qq+4F)MD  
for(int i=1;;i++) BUFv|z+H  
{ |ZBw<f  
String header=con.getHeaderFieldKey(i); 1M-pr 8:6s  
if(header!=null) ^Cmyx3O^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6~{C.No}  
Utility.log(header+" : "+con.getHeaderField(header)); eyaNs{TV  
else QJNFA}*>  
break; }G=M2V<L  
} X]=t>   
} ;<5q]/IHK  
`/g UV  
[lAp62i5  
public void splitterStop() wr4:Go`  
{ NI5``BwpO  
bStop = true; fM}#ON>Z  
} +p^u^a  
v=k$A  
tkhCw/  
} 5xde;  
MDN--p08  
BVm0{*-[|  
/* DlT{`  
**FileAccess.java _wcNgFx  
*//文件访问(定位,写) BY*Q_Et  
package NetFox; E4!Fupkpf  
import java.io.*; \ jA~9  
.543N<w  
^{{q V  
public class FileAccessI implements Serializable{ tgaO!{9I?  
u>$t'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X 8|EHb<  
RandomAccessFile oSavedFile; `6YN3XS  
long nPos; K^$=dLp  
':W[A  
HDKbF/  
public FileAccessI() throws IOException F?cK- .  
{ DMS! a$4  
this("",0); *H122njH+T  
} :4s1CC+@\  
_U0f=m  
1}37Q&2  
public FileAccessI(String sName,long nPos) throws IOException fh{`Mz,o  
{ q;U,s)Uz^  
oSavedFile = new RandomAccessFile(sName,"rw"); 9kojLqCT  
this.nPos = nPos; 7KPwQ?SjT  
oSavedFile.seek(nPos); GL JMP^p  
} &{RDM~  
G j1_!.T  
ca}2TT&t  
public synchronized int write(byte[] b,int nStart,int nLen) -+5>|N#  
{ {t!!Uz 7  
int n = -1; fV:83|eQ  
try{ b\ PgVBf9  
oSavedFile.write(b,nStart,nLen); +3`alHUK  
n = nLen; [V!tVDs&'o  
} dd["dBIZ '  
catch(IOException e) 2Hdu:"j  
{ ]d`VT)~vje  
e.printStackTrace (); *dF>_F  
} OH"XrCX7n  
e%6QTg5#  
&?vgP!d&M  
return n; i&k7-<  
} 6Iw\c  
P&q7|ST%N  
cFv8 Od  
} qVPeB,kIz  
rbQR,Nf2x  
CNIsZ v@Q  
/* RL<c>PY  
**SiteInfoBean.java Ha ]YJ}  
*/ 5?L<N:;J_  
package NetFox; KU;9}!#  
d1kJRJ   
xCKRxF  
public class SiteInfoBean { 0g\(+Qg^  
[r-p]"R  
1sCR4L:+  
private String sSiteURL; //Site's URL <ih[TtZ  
private String sFilePath; //Saved File's Path -![|}pX  
private String sFileName; //Saved File's Name +*^H#|!  
private int nSplitter; //Count of Splited Downloading File }-fl$j?9E  
" Jr-J#gg  
&[SC|=U'M  
public SiteInfoBean() kN>!2UfNS  
{//nSplitter的缺省值为5 Wl Sm  
//default value of nSplitter is 5 Sc   
this("","","",5); ZC}QId  
} T)}) pt!V  
`lPfb[b  
ipILG4  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5-G@L?~Vw  
{ j7c3(*Pl  
sSiteURL= sURL; wPl%20t  
sFilePath = sPath; pmilrZmm]  
sFileName = sName; \;-|-8Q  
this.nSplitter = nSpiltter; 4X$Qu6#i  
s@DLt+ O5  
iX\X>W$P  
} d| {r5[&  
g*"P:n71  
M[uA@  
public String getSSiteURL() Dxxm="FQZ  
{ m6djeOl  
return sSiteURL; K@#L)VT!  
} )ANmIwmC#  
q]M0md  
N?>vd*  
public void setSSiteURL(String value) `@ FYkH  
{ jSAjcLR  
sSiteURL = value; s0_nLbWwO  
} aA TA9V  
9E tz[`|  
-]=@s  
public String getSFilePath() ((I%'   
{ N!|wo:  
return sFilePath; 2Gdd*=4z  
} n}V_,:Z  
`KQvJjA6  
4H-'Dr=G  
public void setSFilePath(String value) rt| 7h>RQ  
{ ^KELKv,_  
sFilePath = value; &w~d_</  
} FE{FGM q  
LD g?'y;2  
/SrAW`;"  
public String getSFileName() J'2X&2  
{ 6DWgl$[[  
return sFileName; [h:T*(R?  
} p"Z-6m~  
eN~=*Mn(za  
3{h_&Gbo'D  
public void setSFileName(String value) !L8#@BjU  
{ $pudoAO  
sFileName = value; +KEWP\r  
} )tpL#J  
i@ BtM9:  
U3:j'Su4H?  
public int getNSplitter() nQ L@hc  
{ S[T8T|_  
return nSplitter; Q dp)cT  
} B~du-Z22IZ  
s!e3|pGS  
M:6"H%h,W  
public void setNSplitter(int nCount) I0 RvnMw  
{ BRYHX.}h\A  
nSplitter = nCount; ^ K E%C;u  
} +t:0SRSt  
} (@}!0[[^  
{91nL'-'  
kE(mVyLQ  
/* 0<B$#8  
**Utility.java tdaL/rRe  
*/ y#$CMf -q^  
package NetFox; /^|Dbx!u  
R^e.s -  
s|B3~Q]  
public class Utility { &l[$*<P5V  
&(mR> mT  
-FCe:iY! A  
public Utility() !&Pui{F  
{ D #/Bx[  
[ps*uva  
N{~Y J$!8  
} BI}Cg{^km  
3 SGDy]  
//线程睡眠 HOh!Xcu  
public static void sleep(int nSecond) 14'45  
{ .k \@zQ|Ta  
try{ u=_mvN  
Thread.sleep(nSecond); t@Nyr&|D  
} Dl8;$~  
catch(Exception e) M {Q;:  
{ wIBO ^w\J  
e.printStackTrace (); 8Dm%@*B^b  
} K:Q<CQ2  
} iRi-cQVy  
[R7Y}k:9U  
//日志 s&!a  
public static void log(String sMsg) '-/xyAzS  
{ -8rjgB~."/  
System.err.println(sMsg); aCLqk'  
} A6iq[b]  
Nl(3Xqov  
fe#\TNeQJ[  
public static void log(int sMsg) D+7Rz_=  
{ q=qcm`ce  
System.err.println(sMsg); qc~iQSI  
} U2~kJ  
} ?#YE`]  
CoAv Sw  
VgC2+APg  
/* y {<9]'  
**TestMethod.java M_w<m  
*/ (41|'eB\\  
package NetFox; ^Uh BH@ti  
JO"<{ngsQ  
DXK}-4"\  
public class TestMethod { JOim3(5?s  
A:9?ZI/X  
fn 6J *[`  
public TestMethod() }t1a* z  
{ ///xx/weblogic60b2_win.exe Z} r*K%  
try{ 2oRg 2R}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); B\:%ufd ~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )sp4Ie  
SiteFileFetch fileFetch = new SiteFileFetch(bean); h_IDO%  
fileFetch.start(); ""Q P%  
} n`&U~s8w  
catch(Exception e){e.printStackTrace ();} x6ARzH\  
2q4<t:!  
PO 7Lf#9]  
} /mu*-,a eX  
JyOo1E.  
c+nq] xOs'  
public static void main(String[] args) 0aa&m[Mk  
{ (%W&4a1di  
new TestMethod(); ^7KH _t8  
} g5QZ0Qkj  
} x&T[*i  
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