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http断点续传简单实现(java)

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/* wV,=hMTd&\  
**SiteFileFetch.java {vur9L  
*/ rym*W\AWx  
package NetFox; #r]GnC,  
import java.io.*; C}\kp0mz  
import java.net.*;  !>Q{co'  
"WH &BhQYD  
wkT4R\H>  
public class SiteFileFetch extends Thread { [5Zi\'~UH)  
'lmjZ{k  
l !ZzJ&  
SiteInfoBean siteInfoBean = null; //文件信息Bean muO;g&  
long[] nStartPos; //开始位置 A@reIt  
long[] nEndPos; //结束位置 ?28)l 4 Ml  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {_ZbPPh;M"  
long nFileLength; //文件长度 nFwdW@E9  
boolean bFirst = true; //是否第一次取文件 =.,XJIw&  
boolean bStop = false; //停止标志 |@hyGu-H+  
File tmpFile; //文件下载的临时信息 @Y#TWt#  
DataOutputStream output; //输出到文件的输出流 X"%eRW&qu/  
^b*ub(5Ot  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) EdZNmL3cB  
public SiteFileFetch(SiteInfoBean bean) throws IOException xFyBF[c  
{ UN:cRH{?*  
siteInfoBean = bean; HN<e)E38  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ?yA 2N;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _V` QvnT}  
if(tmpFile.exists ()) ~L.5;8a3Pe  
{ {(h!JeQ  
bFirst = false; 7 *4i0{]  
read_nPos(); <lWBhrz  
} ~u r}6T  
else lLEEre  
{ 8_3WCbe/  
nStartPos = new long[bean.getNSplitter()]; h9 rrkV9  
nEndPos = new long[bean.getNSplitter()]; ?l`|j*  
} f1U: _V^d  
=-G4 BQ  
xww\L &y  
OGW0lnQ/  
} jjg&C9w T  
,fj~BkW{  
T? ,Q=.  
public void run() 3) XS^WG  
{ ca%XA|_J  
//获得文件长度 .GFKy  
//分割文件 ,|w,  
//实例FileSplitterFetch Wr,pm#gl6  
//启动FileSplitterFetch线程 M$3/jl*#}  
//等待子线程返回 fg GTm:   
try{ ,_:6qn{  
if(bFirst) &CfzhIi*!  
{ t_qX7P8+'  
nFileLength = getFileSize(); F^Mt}`O  
if(nFileLength == -1) h\8bo=  
{ j)}TZx4~  
System.err.println("File Length is not known!"); M*F`s& vM  
} ' &Nv|v\V  
else if(nFileLength == -2) N Q }5'  
{ +sXnC\  
System.err.println("File is not access!"); DMT2~mh  
} 5 gwEr170  
else ) 3I|6iS  
{ %i&\ X[  
for(int i=0;i<nStartPos.length;i++) RG- ,<G`  
{ ST\d -x  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); T"E%;'(cp)  
} -i4hJC!3  
for(int i=0;i<nEndPos.length-1;i++) Ev&aD  
{ ^1XnnQa  
nEndPos = nStartPos[i+1]; ~bfjP2 g  
} R#/0}+-M  
nEndPos[nEndPos.length-1] = nFileLength; Qa1G0qMEIF  
} g]._J  
} 5 ~"m$/yE  
ZMch2 U8  
3UJSK+d\  
//启动子线程 7gt%[r M  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $oZV 54  
for(int i=0;i<nStartPos.length;i++) D+*_iM6[-  
{ K Z0%J5  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YTfMYH=}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), u6*mHkM  
nStartPos,nEndPos,i); #F+b^WTR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !3o]mBH8  
fileSplitterFetch.start(); fJn4'Q*U  
} KPa&P:R3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wr2F]1bh@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); U?ZxQj66}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `e5f69"  
nEndPos = " + nFileLength); ^2mCF  
// fileSplitterFetch[nPos.length-1].start(); hle@= e/n  
%UCuI9  
}k6gO0z  
//等待子线程结束 1VG7[#Zy  
//int count = 0; _i0,?U2C  
//是否结束while循环 s?&UFyYb,  
boolean breakWhile = false; <2PO3w?Z  
`R:HMO[ow  
9Oc(Gl5az  
while(!bStop) !(qaudX{>k  
{ 6CzN[R}  
write_nPos(); It8@Cp.dU  
Utility.sleep(500); <Kq!)) J'  
breakWhile = true; -)E6{  
YuzgR;Z  
L%4Do*V&  
for(int i=0;i<nStartPos.length;i++) Z'y:r2{ql  
{ s=)1:jY k  
if(!fileSplitterFetch.bDownOver) g]}E1H6-  
{ lLuAgds`  
breakWhile = false; n}q/:|c  
break; X6o iOs  
} ['@R]Si"!  
} 5~xv"S(E}  
if(breakWhile) 4+a u6ABy  
break; aP +)  
Evq^c5n>{  
S{)'1J_0  
//count++; q6V\n:hKV  
//if(count>4) )}T0SGY  
// siteStop(); y3mJO[U0 a  
} 9 X87"  
oz\r0:  
liVj-*m  
System.err.println("文件下载结束!"); Gu K!<-Oz"  
} ziD+% -  
catch(Exception e){e.printStackTrace ();} k0-,qM#p;X  
} <>[]- Vq  
q=uJ^N  
mV'^4by  
//获得文件长度  ?r(Bu  
public long getFileSize() wfBf&Z0{  
{ RQd5Q.  
int nFileLength = -1; ~@EBW3>~5  
try{ @m ?&7{y#?  
URL url = new URL(siteInfoBean.getSSiteURL()); O:te;lQ K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Xq.G vZS`  
httpConnection.setRequestProperty("User-Agent","NetFox"); A*+KlhT  
8J+:5b_?  
F$>^pw  
int responseCode=httpConnection.getResponseCode(); RyN?Sn5)  
if(responseCode>=400) ;NrU|g/ksX  
{ .k:Uj-&  
processErrorCode(responseCode); M9dUo7  
return -2; //-2 represent access is error |%7OI#t^  
} N^By#Z  
"%{J$o  
/N\[ C"8  
String sHeader; uHpSE?y/  
[}=/?(5  
rTLo6wI  
for(int i=1;;i++) t[?O*>  
{ u7ER  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *6 1G<I  
//Utility.log(in.readLine()); agxR V  
sHeader=httpConnection.getHeaderFieldKey(i); )l*6zn`z  
if(sHeader!=null)  Q~AK0W  
{ 73'.TReK  
if(sHeader.equals("Content-Length")) h**mAa0fo  
{ FQ6{NMz,h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); gjhWoZV  
break; =[V  
} Z\P&i#  
} ,[0rh%%j  
else <{b#nPc!,#  
break; IBe0?F #  
} $sR-J'EE!  
} 4 | DGQ  
catch(IOException e){e.printStackTrace ();} Dh{sVRA  
catch(Exception e){e.printStackTrace ();} b0"R |d[i  
@mrGG F  
LzJNQd'  
Utility.log(nFileLength); !)TO2?,^  
:p,DAt}  
Zp*0%x!e  
return nFileLength; K=X13As_  
} NKS-G2 Y<P  
b py576GwA  
)nJh) {4\  
//保存下载信息(文件指针位置) (xhV>hsA  
private void write_nPos() dGBVkb4]T  
{ tcU4$%H/  
try{ Af_yb`W?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); A/{0J\pA  
output.writeInt(nStartPos.length); dk4|*l-  
for(int i=0;i<nStartPos.length;i++) SRf .8j  
{ G%RhNwm  
// output.writeLong(nPos); mBZg(TY  
output.writeLong(fileSplitterFetch.nStartPos); gw);b)&mx  
output.writeLong(fileSplitterFetch.nEndPos); _f5n t:-  
} 8]-c4zK  
output.close(); +XN/ bT  
} b".e6zev  
catch(IOException e){e.printStackTrace ();} p[M*<==4  
catch(Exception e){e.printStackTrace ();} F),wj8#~>-  
} ON/U0V:v  
fA>FU/r  
2pQdDbm  
//读取保存的下载信息(文件指针位置) FlQ(iv)P  
private void read_nPos() }c~o3t(7`b  
{ -%#F5br%  
try{ "G3zl{?GP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8o4?mhqV  
int nCount = input.readInt(); S;FgS:;  
nStartPos = new long[nCount]; 8h| 9;%  
nEndPos = new long[nCount]; |ydOi&  
for(int i=0;i<nStartPos.length;i++) X0QLT:J b  
{ 9F^rXY.  
nStartPos = input.readLong(); UjI -<|  
nEndPos = input.readLong(); oDEvhN T  
} SYsbe 5j  
input.close(); !Cv:,q  
} I>L@ P`d  
catch(IOException e){e.printStackTrace ();} ]aF!0Fln~  
catch(Exception e){e.printStackTrace ();} 79JU   
} YKT=0   
IJt8 * cw  
Z#P:C":e  
private void processErrorCode(int nErrorCode) -N]%) Hy  
{ f~NGIlgR  
System.err.println("Error Code : " + nErrorCode); p:n.:GZ=y  
} D-IXO @x  
0cBk/x^s  
X}s}E ;v9  
//停止文件下载 #^ cmh  
public void siteStop() &^4E)F  
{ "dO>P*k,  
bStop = true; Hkck=@>8H*  
for(int i=0;i<nStartPos.length;i++) U F ]g6u  
fileSplitterFetch.splitterStop(); XV> )[Nd\H  
P,@ :?6  
NlnmeTLO5  
} ADQ#qA,/  
} <CnTiS#  
//负责部分文件的抓取 ;=[~2*8  
**FileSplitterFetch.java c/q -WEKL  
*/ m|5yET  
package NetFox; w0FkKJV  
$J] b+Bp  
X^;LiwQv  
import java.io.*; BCK0fk~  
import java.net.*; T+y3Ph--^  
5@xl/  
;%H/^b.c  
public class FileSplitterFetch extends Thread { @a{1vT9b  
|tkhsQ-;  
*j0kb"#  
String sURL; //File URL LYv$U;*+  
long nStartPos; //File Snippet Start Position b\l +S2  
long nEndPos; //File Snippet End Position `Ko6;s#  
int nThreadID; //Thread's ID CI };$4W~  
boolean bDownOver = false; //Downing is over XvIrO]F-  
boolean bStop = false; //Stop identical ED+tVXyw  
FileAccessI fileAccessI = null; //File Access interface eZ^-gk?  
-:|1>og  
{IlX@qWr  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `1eGsd,f  
{ z` :uvEX0  
this.sURL = sURL; JWuF ?<+k  
this.nStartPos = nStart; !VJ5(b  
this.nEndPos = nEnd; `V1D &}H+G  
nThreadID = id; 'kz[Gh*8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 V!Q1o!J  
} UvtSNP&/2d  
9Xv>FVG!  
Jn>6y:s  
public void run() Jt3]'Nr04@  
{ c88I"5@[bD  
while(nStartPos < nEndPos && !bStop) cF7efs8u  
{ ;P{HePs=)  
_26~<gU8  
wSMP^kG  
try{ /5y*ZIq]e  
URL url = new URL(sURL); ]^63n/Twj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >,Zf3M  
httpConnection.setRequestProperty("User-Agent","NetFox"); V>`xTQG  
String sProperty = "bytes="+nStartPos+"-"; vl'2O7  
httpConnection.setRequestProperty("RANGE",sProperty); %0z&k!P  
Utility.log(sProperty); SbLx`]rI  
#$GDKK  
:$`"M#vMX  
InputStream input = httpConnection.getInputStream(); `]{/(pIgW;  
//logResponseHead(httpConnection); fA]b'8  
)aOPR|+  
HktvUJ(Ii  
byte[] b = new byte[1024]; Y!8Ik(/~i  
int nRead; -2dk8]KB]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) cG"+n@ \  
{ H ',Nt  
nStartPos += fileAccessI.write(b,0,nRead); Fj`6v"h  
//if(nThreadID == 1) u5, \Kz  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w1je|Oil  
} `~bnshUk  
2^}E!(<  
*[(}rpp M  
Utility.log("Thread " + nThreadID + " is over!"); y3 R+060\3  
bDownOver = true; L;7x2&  
//nPos = fileAccessI.write (b,0,nRead); 0t-!6  
} @@,l0/  
catch(Exception e){e.printStackTrace ();} 1HF=,K+  
} Ri}n0}I  
} $LLy#h?V]  
>^8=_i !  
=c-,uW11[  
//打印回应的头信息 1?6;Oc^  
public void logResponseHead(HttpURLConnection con) [HKTXF{n  
{ f\ wP}c'  
for(int i=1;;i++) <4gT8 kQ$x  
{ .."=  
String header=con.getHeaderFieldKey(i); D=w5Lks  
if(header!=null) _oB!-#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @c<*l+Qc  
Utility.log(header+" : "+con.getHeaderField(header)); )>]~Y  
else Wb_'X |"u  
break; Wgt[ACioN  
} OIuEC7XM^C  
} C>d_a;pX  
z8SrZ#mg  
/mb?C/CI  
public void splitterStop() A{5^A)$  
{ *20$u% z2  
bStop = true; <_S>-;by  
} l@x/{0  
,Qgxf';+$  
>Jl(9)e  
} gg>O:np8  
DA5kox&cU  
Z\{"/( Hi  
/* `g2DN#q[0  
**FileAccess.java `wJR^O!e  
*//文件访问(定位,写) 6]=R#d 7U  
package NetFox; ,qS-T'[v,(  
import java.io.*; Hoaf3 `n  
):@XMECa  
#Z'r;YOzs  
public class FileAccessI implements Serializable{ d66 GO];"  
73kF=*m  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,;aELhMZ  
RandomAccessFile oSavedFile; *(%]|z}]m  
long nPos; 87Sqs1>cw  
cr{;gP  
+ht -Bl  
public FileAccessI() throws IOException <<zYF.9L]  
{ KaJCfu yp  
this("",0); w`kn!k8  
} Tl.dr   
_H:mBk,,  
zj ;'0Zu  
public FileAccessI(String sName,long nPos) throws IOException Y<'T;@  
{ 6!|-,t><  
oSavedFile = new RandomAccessFile(sName,"rw"); 2]Nc@wX`p  
this.nPos = nPos; CS;bm `8a  
oSavedFile.seek(nPos); f$G{7%9*  
} jl;%?bx  
iRo/~(  
""GeO%J8  
public synchronized int write(byte[] b,int nStart,int nLen) Jww LAQ5  
{ !TJCQ[Aa }  
int n = -1; v !~lVv&  
try{ oUMY?[Wp  
oSavedFile.write(b,nStart,nLen); O@@=ZyYwc  
n = nLen; GXV<fc"1  
} WD=#. $z$  
catch(IOException e) N`FgjnQ`  
{ "XWrd [Df  
e.printStackTrace (); CNCWxu  
} Cv@ZzILyoK  
K&zp2V  
uyt]\zVT  
return n; ]] R*sd*  
} ?0>% a$`  
S]kY'(V(*  
J2\%rb,  
} F;5S2:a@Z  
g$c\(isY;  
YQb43Sh`  
/* ;naD`([  
**SiteInfoBean.java _lrCf  
*/ >wiW(Ki}  
package NetFox; I:4m]q b  
$F|3VQ~  
[whX),3>  
public class SiteInfoBean { l6^IX0&p  
f; <qGM.#|  
4{?Djnh  
private String sSiteURL; //Site's URL Y#9dVUS  
private String sFilePath; //Saved File's Path EV}c,*);y  
private String sFileName; //Saved File's Name oe<9CK:?>  
private int nSplitter; //Count of Splited Downloading File "*E#4e[  
Rf)lFi  
*.X!AJ;M=O  
public SiteInfoBean() P4x Q:$2!  
{//nSplitter的缺省值为5 ? Xb8B5  
//default value of nSplitter is 5 j]uL 9\>  
this("","","",5); |{ E\ 2U  
} T %   
ys+ AY^/  
GCn^+`.h1t  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `:hEc<_/  
{ 1]wx Ru  
sSiteURL= sURL; ?!R Z~~d  
sFilePath = sPath; C5Fk>[fS  
sFileName = sName; >k gL N  
this.nSplitter = nSpiltter; |D `r o  
J7FCW^-`3  
~)';[Ha  
} 5l"/lGw  
W`}C0[%VW  
f>LwsP  
public String getSSiteURL() l+e L:C!  
{ S+03aJNN#  
return sSiteURL; ''+6qH-.|]  
} iNn]~L1  
|a7W@LVYD  
?}y{tav=  
public void setSSiteURL(String value) y:6&P6`dx  
{ }co v"o  
sSiteURL = value; vYT%e:8)q  
} Nqih LUv  
YzTmXwuA5  
F`W8\u'db  
public String getSFilePath() 739J] M  
{ E;[ANy4L  
return sFilePath; V2< 4~J2:9  
} m_{?py@tZ  
. zM  
dgb#PxOMH  
public void setSFilePath(String value) ;J"b%~Gn  
{ 9|Z25_sS  
sFilePath = value; 1 J3h_z6/  
} gv7(-I  
k)VoDxMKK  
L B:wo .X  
public String getSFileName() U#=Q`  
{ K OZHz`1!  
return sFileName; H{Zfbb  
} W'f{u&<  
Ey5E1$w%&  
Z:Hk'|q}I  
public void setSFileName(String value) A"wor\(  
{ YQU #aOl  
sFileName = value; ET ;=o+\d  
} m2!y;)F0  
gwvy$H   
Q+d9D1b  
public int getNSplitter() pNY+E5  
{ !{@!:m3w  
return nSplitter; d|UK=B^x  
} o $k1&hyH  
IuJj ;L1  
0~qnwe[g}  
public void setNSplitter(int nCount) %<x2=#0  
{ /\=syl  
nSplitter = nCount; L;a> J  
} -]1F ] d  
} }@-4*5P3  
B(<;]  
:Oz! M&Ov  
/* -rYOx9P4  
**Utility.java *,w9#?2x  
*/ 'je=.{[lWt  
package NetFox; 7<W7pXDp  
<VB;J5Rv  
xngK_n  
public class Utility { $_N<! h*\  
sxq'uF(K  
$0[T=9q <+  
public Utility() MjIp~?*  
{ tOn_S@/r  
y99 3uP   
16q"A$  
} ]=5nC)|  
,U_p6 TV5  
//线程睡眠 T\g%.  
public static void sleep(int nSecond) RIXUzKLO  
{ Fs rGI (x?  
try{ cwK 6$Ax  
Thread.sleep(nSecond); @pueM+(L&  
} b"-eQb  
catch(Exception e) p#:.,;  
{ p s:|YR  
e.printStackTrace (); U0}]3a0  
} 4%#C _pE9  
} :cv_G;?  
86J7%;^Xa  
//日志 E}S)uI,gn  
public static void log(String sMsg) H]a;<V9[  
{ &M$s@FUY  
System.err.println(sMsg); O9>& E;`5  
} (;^VdiJ  
o,a 3J:j]  
$j(2M?.>#  
public static void log(int sMsg) > <WR]`G  
{ g0@i[&A@{  
System.err.println(sMsg); `$|!h-"  
} 9;3f`DK@2k  
} [([?+Ouy  
y>zPsc,  
mZ9+.lm  
/* {5}UP@h  
**TestMethod.java 0*?~I;.2m$  
*/ q=8I0E&q  
package NetFox; yw'b^D/  
^Xjh?+WM  
OyVdQ".  
public class TestMethod { 1-C 2Y `  
KL]@y!QU  
g0w<vD`<g  
public TestMethod() $0rSb0[  
{ ///xx/weblogic60b2_win.exe W2Y%PD9a  
try{ XjpFJ#T*$A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); AtNu:U$  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); e-Z+)4fH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); b?U!<s.  
fileFetch.start(); %H\i}}PTe  
} CA[-\>J7y  
catch(Exception e){e.printStackTrace ();} aagN-/mgm  
Cs$wgm*  
=VkbymIZ4y  
} pNFL;k+p}  
h@$M.h@mcG  
@;m7u  
public static void main(String[] args) /YYI 4  
{ wkm;yCF+  
new TestMethod(); SEm3T4dfzf  
} ,ZyTYD|7  
} <F!On5=W*  
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