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http断点续传简单实现(java)

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/* ][y~(&=T  
**SiteFileFetch.java C& QT-|  
*/ AGe\PCn-  
package NetFox; tJQFhY  
import java.io.*; M;{btu^a  
import java.net.*; c9eLNVM  
kq SpZoV0'  
Nn_n@K  
public class SiteFileFetch extends Thread { 4{s3S2f =  
D# "ppa}  
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SiteInfoBean siteInfoBean = null; //文件信息Bean MyyNYZ  
long[] nStartPos; //开始位置 .cV<(J 5o  
long[] nEndPos; //结束位置 gJ8+HV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 fgW>U*.ar  
long nFileLength; //文件长度 vThK@P!s  
boolean bFirst = true; //是否第一次取文件 O7_u9lz2  
boolean bStop = false; //停止标志 R4V~+tnbG&  
File tmpFile; //文件下载的临时信息 v?U;o&L(  
DataOutputStream output; //输出到文件的输出流 g(i_di  
ugwZAC  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) XRMYR97  
public SiteFileFetch(SiteInfoBean bean) throws IOException FKOTv2  
{ 12yr_   
siteInfoBean = bean; SGd[cA Ko  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _^2rRz  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); hw@ `Q@  
if(tmpFile.exists ()) e7(iMe  
{ OUd&fUmH  
bFirst = false; QD6in>+B@  
read_nPos(); (Mk9##R#  
} |Mj2lZS  
else (W~')A"hC'  
{ \D9J!K82  
nStartPos = new long[bean.getNSplitter()]; oM&}akPE  
nEndPos = new long[bean.getNSplitter()]; B J0P1vh6M  
} }'y=JV>l  
\Tc<27-  
W_%p'8,  
b=5"*=T{+  
} |bwz  
Lad8C  
O]>FNsh!  
public void run() LovVJ^TD0i  
{ ^Lx(if WJ  
//获得文件长度 ,co~@a@9  
//分割文件 &X^ -|7~N  
//实例FileSplitterFetch /YP,Wfd%  
//启动FileSplitterFetch线程 {xFgPtCM  
//等待子线程返回 zT\nj&7  
try{ [ p+]H?(A  
if(bFirst) (V:z7  
{  =V- ^  
nFileLength = getFileSize(); 8gQg#^,(t  
if(nFileLength == -1) [O"9OW'2!B  
{ k//l~A9m  
System.err.println("File Length is not known!"); X7cqAi  
} <}G*/ z?/  
else if(nFileLength == -2) 0%Y8M` ~s7  
{ fd{75J5%  
System.err.println("File is not access!"); =i4%KF9 x  
} ig Q,ZY1  
else >tmv3_<=  
{ A)2eo<ij4  
for(int i=0;i<nStartPos.length;i++) Ej\M e  
{ k$kOp *X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); vn]e`O>y  
} MY8[)<q"  
for(int i=0;i<nEndPos.length-1;i++) <6 HrHw_  
{ KI@OEy  
nEndPos = nStartPos[i+1]; 4jOq.j  
} 5Iql%~_x  
nEndPos[nEndPos.length-1] = nFileLength; K}vP0O}  
} DLigpid  
} "Je*70LG#  
fEdp^oVg  
kM0TQX)$m  
//启动子线程 Bb,l.w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3Kx&+  
for(int i=0;i<nStartPos.length;i++) =bx;TV  
{ TpB4VNi/<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #2/2X v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 88@" +2  
nStartPos,nEndPos,i); | ODi[~y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FZvh]ZX  
fileSplitterFetch.start(); :7WeR0*%  
} BHNcE*U}@?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CAbeb+O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6T?$m7c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .T2P%Jn.  
nEndPos = " + nFileLength); pR3@loFQ`o  
// fileSplitterFetch[nPos.length-1].start(); >@Nn_d  
m-< "`:+  
X,] E {  
//等待子线程结束 LU-,B?1  
//int count = 0; c:J;Q){Xz  
//是否结束while循环 ii3{HJ*C  
boolean breakWhile = false; \ah.@s  
A~@u#]]<n  
{Rm N1'%  
while(!bStop) ;JD/4:  
{ lYF~CNvE  
write_nPos(); m@Q%)sc)  
Utility.sleep(500); c%jW'  
breakWhile = true; ezq<)gJc  
/8Sr(  
q':P9 o*N?  
for(int i=0;i<nStartPos.length;i++) =tKb7:KU  
{ (GeOD V?U  
if(!fileSplitterFetch.bDownOver) hxB` hu-  
{ `kRv+Qwfa  
breakWhile = false; Z\\'0yuY(  
break; ^Fn~@'  
} B24,;2J  
} xJ);P.  
if(breakWhile) @@ 1Sxv_  
break; `|rr<Tsy\  
[U^@Bkh  
R5,ISD +s  
//count++; ;Y^.SR"  
//if(count>4) (}4]U=/nV  
// siteStop(); h1(GzL%i_  
} +o4W8f=Ga  
fz[-pJ5[  
\#hp,XV>  
System.err.println("文件下载结束!"); [ r<0[  
} C$<['D?8  
catch(Exception e){e.printStackTrace ();} 1MPn{#Ff  
} J"$Y`;  
x1O]@Z{d\  
S^ ,q{x*T  
//获得文件长度 &gr)U3w  
public long getFileSize() O>M4%p  
{ e8Y;~OAj[  
int nFileLength = -1; <hv {,1p-r  
try{ aANzL  
URL url = new URL(siteInfoBean.getSSiteURL()); !&f>,?wlP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (2l?~CaK  
httpConnection.setRequestProperty("User-Agent","NetFox"); @hG]Gs[,o  
OsGKlWM/  
`{B<|W$=  
int responseCode=httpConnection.getResponseCode(); W]-c`32~S  
if(responseCode>=400) vJ a?5Jr  
{ *#| lhf'  
processErrorCode(responseCode); [b?[LK}.  
return -2; //-2 represent access is error ?r%kif)  
} :~ ; 48m  
B.oD9 <9  
6+iZJgwAy  
String sHeader; gz~)v\5D/  
%8]~+ #]p  
 &$ x1^  
for(int i=1;;i++) !D!1%@ e  
{ ,WKWin  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  9EU0R H  
//Utility.log(in.readLine()); DOa%|H'P  
sHeader=httpConnection.getHeaderFieldKey(i); ukAE7O(W&  
if(sHeader!=null) :W6R]y  
{ Ltrw)H}  
if(sHeader.equals("Content-Length")) PX$_."WA  
{ a^>e| Eq|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); H7}@56  
break; 6$y$ VeW  
} .*,W%r?1n6  
} )bkJ[ '9  
else DZ*m"Bi  
break; .271at#-  
} p4sU:  
} 7A6:*  
catch(IOException e){e.printStackTrace ();} tDQo1,(oY  
catch(Exception e){e.printStackTrace ();} z"PU`v  
Vgg' 5o&.  
SU$%nK)  
Utility.log(nFileLength); 7W7yjG3g  
j +u3VP  
O ,Sqh$6U  
return nFileLength; }%lk$g';  
} !hc#il'g].  
l(j._j~p  
q Xj]O3 mm  
//保存下载信息(文件指针位置) >713H!uj  
private void write_nPos() 62Q`&n6  
{ ~ ~U,  
try{ l2ww3)Z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Y2&hf6BE  
output.writeInt(nStartPos.length); } >z l  
for(int i=0;i<nStartPos.length;i++) &f_ua)cyY  
{ 6EY W:o  
// output.writeLong(nPos); 11Y4oS  
output.writeLong(fileSplitterFetch.nStartPos); s<b(@L 1  
output.writeLong(fileSplitterFetch.nEndPos); 9_&N0>OF  
} U3rpmml  
output.close(); RGC DC*\  
} L8.u7(-#  
catch(IOException e){e.printStackTrace ();} zYZ^/7)  
catch(Exception e){e.printStackTrace ();} ^3 6oqe{  
} eZ`x[g%1  
$:!L38[7$  
0WO-+eRB/  
//读取保存的下载信息(文件指针位置) %&\DCAFk  
private void read_nPos() X6 SqOb\(a  
{ Z-;I,\Y%  
try{ O[|prk,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i^_?C5  
int nCount = input.readInt(); r(i!".Z  
nStartPos = new long[nCount]; ?'%9  
nEndPos = new long[nCount]; sNbCOTow  
for(int i=0;i<nStartPos.length;i++) qV&ai{G:  
{ YLkdT%  
nStartPos = input.readLong(); y|h:{<  
nEndPos = input.readLong(); vIpitbFC  
} \ x>#bql+  
input.close(); 227 Z6#CF!  
} 3Jj 3!aDB  
catch(IOException e){e.printStackTrace ();} ^oH!FN`;{  
catch(Exception e){e.printStackTrace ();} Fb^f`UI  
} k.K;7GZC  
&:}}T=@M1  
^QbaMX  
private void processErrorCode(int nErrorCode) US2Tdmy@05  
{ &?(472<f**  
System.err.println("Error Code : " + nErrorCode); daN#6e4Z+;  
} NU |vtD  
[D= KI&@&O  
GGF;4  
//停止文件下载 F2WMts  
public void siteStop() i8 fUzg)  
{ +~l`rJ  
bStop = true; @(I)]Ca%O  
for(int i=0;i<nStartPos.length;i++) snti*e4"V  
fileSplitterFetch.splitterStop(); fF.qQTy;7  
}$D{YHF  
kXY p.IVA  
} ;UoXj+Z  
} F ?.J1]  
//负责部分文件的抓取 g6l&;S40  
**FileSplitterFetch.java OaCp3No  
*/ eW.[M?,  
package NetFox; {q^?Rw  
w W1>#F  
!dZpV~g0  
import java.io.*; a/s6|ri`0  
import java.net.*; ; +%|!~  
O$$$1VHYo  
NUb:5tL  
public class FileSplitterFetch extends Thread { +8eW/Bs@2  
0{zA6Xu  
,W:Bh$%  
String sURL; //File URL K.I  \E  
long nStartPos; //File Snippet Start Position e,rCutA)  
long nEndPos; //File Snippet End Position QCVwslj,K  
int nThreadID; //Thread's ID ppXt8G3% x  
boolean bDownOver = false; //Downing is over w?Nx ^)xX  
boolean bStop = false; //Stop identical q@8j[15  
FileAccessI fileAccessI = null; //File Access interface Yt#e[CYnu  
," ~4l&  
!Q" 3B6 86  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +t`QHvxv  
{ W y%'<f  
this.sURL = sURL; I$vM )+v=  
this.nStartPos = nStart; 9<Kc9Z  
this.nEndPos = nEnd; lL]8~3b  
nThreadID = id; v.pj PBU1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }Pf7YuUZZ  
} #M5[TN!  
Tt*n.HA  
o:C],G_  
public void run() DX)T}V&mP  
{ Z2soy-  
while(nStartPos < nEndPos && !bStop) 7\p<k/TS  
{ +' f38D*  
'@ C\,E  
pGhA  
try{ 3t^r;b  
URL url = new URL(sURL); L?~-<k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^"hsbk&Yu  
httpConnection.setRequestProperty("User-Agent","NetFox"); "J(7fL$!  
String sProperty = "bytes="+nStartPos+"-"; T.R(  
httpConnection.setRequestProperty("RANGE",sProperty); j@b18wZ  
Utility.log(sProperty); 2Y'=~*tV  
d/3 k3HdL  
8 ?+t+m[  
InputStream input = httpConnection.getInputStream(); M+q|z0U  
//logResponseHead(httpConnection); ~.'NG? %7P  
1XvB,DhJ  
#w<:H1,4  
byte[] b = new byte[1024]; jf'#2-   
int nRead; BoMf#l.3B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) TRSR5D[  
{ c7$U0JO  
nStartPos += fileAccessI.write(b,0,nRead); )/1,Ogb%_  
//if(nThreadID == 1) Z-BPC|e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;q6FdS  
} B\z4o\am%  
SOPQg?'n=V  
%`Q<_LTU  
Utility.log("Thread " + nThreadID + " is over!"); -A A='s  
bDownOver = true; Axtf,x+lH  
//nPos = fileAccessI.write (b,0,nRead); ,0=@cJ  
} m+Bt9|d  
catch(Exception e){e.printStackTrace ();} beM}({:`  
} ]\Tcy[5  
} U]h5Q.<SG  
!ENb \'>J>  
wZV/]jmlEt  
//打印回应的头信息 jSyF]$"  
public void logResponseHead(HttpURLConnection con) DMY?'Nts!  
{ "jyh.@<  
for(int i=1;;i++) 38hAg uZX  
{ Im\{b=vT  
String header=con.getHeaderFieldKey(i); 8}0O @ wq  
if(header!=null) jLEwFPz  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Zg@NMT  
Utility.log(header+" : "+con.getHeaderField(header)); M6+_Mi.  
else h) . ([  
break; oU.LYz_  
} 1Lf:TQB  
} [|\JIr=of5  
e2v[ma-  
J}-,!3qxW  
public void splitterStop() !a[1rQH  
{ ]zza/O;31(  
bStop = true; oKJj?%dHK9  
} PB :Lj  
e Ert_@}  
K 8gd?88  
} 5r:SBt|/  
9 OC!\' 8  
27t23@{YL  
/* 'RlPj 0Cg  
**FileAccess.java JKkR963 O  
*//文件访问(定位,写) 54Baz  
package NetFox; i 7fQj, q  
import java.io.*; +##b}?S%  
<E(#;F^y  
f3+@u2Pv  
public class FileAccessI implements Serializable{ >!OD[9  
XZv(B^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~7W?W<  
RandomAccessFile oSavedFile; IQS:tL/  
long nPos; T>&d/$;]  
wnL\.%Y^  
0wLu*K5$4E  
public FileAccessI() throws IOException d (Fb_  
{ 7J]tc1-re  
this("",0); Yd4J:  
} aMSX"N"ot  
-|MeC  
n+M:0{Y|  
public FileAccessI(String sName,long nPos) throws IOException .O{2]e$  
{ Ocq.<#||H  
oSavedFile = new RandomAccessFile(sName,"rw"); _(}{=:M?  
this.nPos = nPos; DAG2pc8zA  
oSavedFile.seek(nPos); 1@ )8E`u  
} C|"h]  
gp:,DC?(  
Y{TzN%|LV  
public synchronized int write(byte[] b,int nStart,int nLen) m ?a&XZ  
{ Uj)~>V'  
int n = -1; &k /uR;yw  
try{ XHgwK @GU  
oSavedFile.write(b,nStart,nLen); y#:_K(A" k  
n = nLen; krPwFp2[*  
} )QGj\2I  
catch(IOException e) c|lo%[]R!  
{ ; /fZh:V2  
e.printStackTrace (); GNzk Vy:u  
} yVvO!  
[a;U'v*  
J~6+zBF  
return n; OAMsqeWYA  
} ,~-"EQT  
#YM5P  
bb# F2r4  
} hHsCr@i  
\ %Er%yv)  
{(@M0?  
/* X !g"D6'  
**SiteInfoBean.java 1D03Nbh|5  
*/ \`\& G-\  
package NetFox; +_tK \MN  
.eAN`-t;  
|1zoT|}q  
public class SiteInfoBean { `Ym7XF&  
sr+* q6W  
Q# w`ZQX3  
private String sSiteURL; //Site's URL _-$"F>  
private String sFilePath; //Saved File's Path lC Bb0k2  
private String sFileName; //Saved File's Name cF9bSY_Eh  
private int nSplitter; //Count of Splited Downloading File Xm./XC  
P08=?  
+1R?R9^Fw  
public SiteInfoBean() pe>R2<!$  
{//nSplitter的缺省值为5 =EI>@Y"  
//default value of nSplitter is 5 V(mz||'*  
this("","","",5); (+d7cln  
} +85i;gO5  
=m.Lw  
FUic7>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =T'N6x5@  
{ NGIbUH1[  
sSiteURL= sURL; 0Ym+10g  
sFilePath = sPath; `0Y`]kSY+  
sFileName = sName; zdFO&YHTw  
this.nSplitter = nSpiltter; ?El8:zt?|  
_FXvJ}~m  
f]MKNX  
} )?#*GMWU  
U}ei2q\  
SFVOof#s  
public String getSSiteURL() ~Rd,jfx  
{ 3 f=_F  
return sSiteURL; .UF](  
} @:u>  
"c8 -xG  
T 22tZp  
public void setSSiteURL(String value) FES_:?.0  
{ v#1}( hb  
sSiteURL = value; h+)XLs  
} 'NyIy:  
kR2kV"-l  
pvdM3+6  
public String getSFilePath() n qSjP5  
{ ME"B1 Se\  
return sFilePath; n1+1/  
} ?.t naE  
ru#,pJ=O(  
xj8 yQ Y1  
public void setSFilePath(String value) Y5nj _xQJL  
{ *->2$uWP  
sFilePath = value; ]X y2km]  
} \ng!qN  
\1Tu P}P  
2P3,\L  
public String getSFileName() "Sm'TZx  
{ iI T7pq1  
return sFileName; ctI=|K  
} @r7ekyO8)  
cP#vzFB0>  
h9<*+T  
public void setSFileName(String value) /-%0y2"7  
{ D d['e  
sFileName = value; $gZC"~BR  
} qiEw[3Za]'  
.g/PWEr\I  
8@b,>l$  
public int getNSplitter() |^l17veA@  
{ n hT%_se4  
return nSplitter; mhh^kwW  
} P/%5J3_,  
ca )n*SD  
-rg >y!L  
public void setNSplitter(int nCount) 2F5*C  
{ >6yA+?[:  
nSplitter = nCount; i7rO 5<  
} p;#@#>h  
} \ @XvEx%  
B^|^hZZ>  
`Vph=`0  
/* CMu/n]?c  
**Utility.java ckDWY<@v  
*/ t`F<lOKj  
package NetFox; >|j8j:S[  
i|N%dl+T=  
*vFXe_.  
public class Utility { B\WIoz;'  
\%],pZsA~  
tW$Di*h  
public Utility() d WKjVf  
{ .VD:FFkW  
9):h %o  
oU|yBs1  
} :8( "n1^  
`^d[$IbDW  
//线程睡眠 J}zN]|bz  
public static void sleep(int nSecond) lftT55Tki  
{ z5njblUz  
try{ KOv?p@d  
Thread.sleep(nSecond); @wVq%GG}  
} vZ6_/ew8  
catch(Exception e) Al93x  
{ e-&0f);i  
e.printStackTrace (); |.]g&m)y^h  
} &];:uYmMU  
} Fu%D2%V$/  
i!yu%>:M  
//日志 VbU*&{j  
public static void log(String sMsg) Nbyc,a[o  
{ xZ=6  
System.err.println(sMsg);  []L yu  
} y [jck:  
%f-Uwq&}Y"  
{zNFp#z  
public static void log(int sMsg) mMt~4(5  
{ V;N'?Gu  
System.err.println(sMsg); PR+L6DT_  
} zWA~0l.2  
} .&Ik(792Z&  
?xTdL738  
!C6[m1F  
/* AQ<2 "s  
**TestMethod.java @Jh;YDr`A  
*/ ]DJ] L=T7  
package NetFox; 5f}GV0=n  
|V dr/'  
k$d+w][  
public class TestMethod { (@(rz/H  
LX%UkfA9  
6'a1]K  
public TestMethod() yt 5'2!jc  
{ ///xx/weblogic60b2_win.exe e$Npo<u  
try{ vyhxS.[9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &al\8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); SbYs a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); zNh$d;(O$^  
fileFetch.start(); .dw;b~p  
} z~0f[As.  
catch(Exception e){e.printStackTrace ();} }"\jB  
&Jf67\N  
\L5h&  
} |M$ESj4@  
w+Oo-AGNH  
{8im{]8_  
public static void main(String[] args) J_@`:l0,z  
{ N*{>8iFo4  
new TestMethod(); R64/m9  
} D//uwom  
} WoSJp5By$  
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