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http断点续传简单实现(java)

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/* weNzYMf%  
**SiteFileFetch.java duX0Mc. 0P  
*/ )O,wRd>5  
package NetFox; CF]i}xpWV  
import java.io.*; =%!e(N'p  
import java.net.*; ePf+[pV3  
Dc08D4   
(+|X<Bl:`  
public class SiteFileFetch extends Thread { LmP qLH'(Q  
q5Fs)B  
YiD-F7hf.*  
SiteInfoBean siteInfoBean = null; //文件信息Bean ]JOephX2R  
long[] nStartPos; //开始位置 L2KG0i`+  
long[] nEndPos; //结束位置 h}<0/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Aj [?aL  
long nFileLength; //文件长度 sU\c#|BSC"  
boolean bFirst = true; //是否第一次取文件 x&'o ]Y  
boolean bStop = false; //停止标志 M'kVL0p?vN  
File tmpFile; //文件下载的临时信息 rkkU"l$v  
DataOutputStream output; //输出到文件的输出流 <3d;1o   
Mr-DGLJ  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 6yY.!HRkr  
public SiteFileFetch(SiteInfoBean bean) throws IOException i=YXKe6fD  
{ Bd{4Ae\_+g  
siteInfoBean = bean; Ng\/)^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); C)NC&fV  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); lWW+5  
if(tmpFile.exists ()) *c{wtl@  
{ J^ `hbP+2  
bFirst = false; >ajuk  
read_nPos(); *myG"@P4hW  
} Mtm/}I  
else pe9@N9_5  
{ W4(v6>5l  
nStartPos = new long[bean.getNSplitter()]; sONBQ9  
nEndPos = new long[bean.getNSplitter()]; Bs[nV}c>>  
} wu A^'T  
P''X_1oMC  
+noZ<KFW "  
S=' wJ@?;  
} MU'@2c  
zF8'i=b&  
'Y.Vn P&H  
public void run() []|;qHhC~(  
{ D3`}4 A  
//获得文件长度 ({4]  
//分割文件  9:5:`' b  
//实例FileSplitterFetch " Ya9~6  
//启动FileSplitterFetch线程 'Gjq/L/x  
//等待子线程返回 Ur^j$B}  
try{ @9Q2$  
if(bFirst) 'B_\TU0 O  
{ p,F^0OU2}:  
nFileLength = getFileSize(); 9IA$z\<<w  
if(nFileLength == -1) %a];  
{ 5!Bktgk.  
System.err.println("File Length is not known!"); $6T3y8  
} n 6{2]&sd  
else if(nFileLength == -2) K$H <}e3  
{ piOXo=9H.  
System.err.println("File is not access!"); BYi)j6"  
} UNDi_6Dy   
else 9GgA6#  
{ q_ %cbAcD  
for(int i=0;i<nStartPos.length;i++) @b2`R3}9R  
{ c8{]]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); YD\]{,F|  
} *:_P8G;  
for(int i=0;i<nEndPos.length-1;i++) Q/ZkW  
{ +R6a}d/K  
nEndPos = nStartPos[i+1]; n-o3  
} y:d{jG^  
nEndPos[nEndPos.length-1] = nFileLength; ;gMgj$mI  
} XX6 T$pA6  
} :~zv t  
o%[U  
Z)pz,  
//启动子线程 2Vk\L~K  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; F2 ~%zNe  
for(int i=0;i<nStartPos.length;i++) w5KPB5/zu  
{ 1f#mHt:(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .R5y:O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 99=s4*xzM  
nStartPos,nEndPos,i); R^*K6Ad  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wvMW|  
fileSplitterFetch.start(); cu&,J#r%  
} zP!J/}z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z{R[Wx  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); kS :\Oz\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %+-C3\'  
nEndPos = " + nFileLength); {f/]5x(_  
// fileSplitterFetch[nPos.length-1].start(); w~Ff%p@9  
ZDx@^P y  
V-!"%fO.s  
//等待子线程结束 YE}s  
//int count = 0; 4=Gph  
//是否结束while循环 w!SkWS b,~  
boolean breakWhile = false; l&$$w!n0w  
@ O>&5gB1u  
8' K0L(3[  
while(!bStop) \}_Yd8  
{ '9?;"=6(  
write_nPos(); uj|BQ`k  
Utility.sleep(500); a%BeqSZh  
breakWhile = true; KCuG u}  
Z5(enTy-  
nkDy!"K  
for(int i=0;i<nStartPos.length;i++) |3hY6aty  
{ 8K9$,Ii  
if(!fileSplitterFetch.bDownOver) 2; `=P5V  
{ T]T;$  
breakWhile = false; }_ mT l@*  
break; E7zm{BX]  
} Bi3+)k>u7  
} ,#]t$mzbQ(  
if(breakWhile) x3p ND  
break; ?7MqeR4/E  
=Gk/k}1  
\5)htL1F  
//count++; :_kAl? eJ  
//if(count>4) ]i*](UQ  
// siteStop(); ,`A?!.K$  
} fyWO  
*&Lq!rFS  
SP]IUdE\  
System.err.println("文件下载结束!"); p4K.NdUH  
} L,,*gK  
catch(Exception e){e.printStackTrace ();} ]aryV?!6  
} JUAS$Y  
C0*@0~8$9  
hsKmnH@#  
//获得文件长度 f~{}zGTM:  
public long getFileSize() cbYLU\!  
{ Q&'}BeUbm  
int nFileLength = -1; JRMM?y  
try{ 8 ho[I]  
URL url = new URL(siteInfoBean.getSSiteURL()); 'b*%ixa  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); US [dkbKo  
httpConnection.setRequestProperty("User-Agent","NetFox"); Gfp1mev   
+;}#B~:  
L I>(RMv  
int responseCode=httpConnection.getResponseCode(); )~6zYJ2  
if(responseCode>=400) k>jbcSY(z<  
{ _ee dBpV  
processErrorCode(responseCode); $_H`   
return -2; //-2 represent access is error 4 1a. #o  
} CSPKP#,B0[  
`#-P[q<v-  
sbj(|1,ac  
String sHeader; CzCQFqXI  
xVL5'y1g B  
=qy=-j]  
for(int i=1;;i++) 4_v]O  
{ {O<l[|Ip  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); C:8_m1Y{  
//Utility.log(in.readLine()); :,b iyJt  
sHeader=httpConnection.getHeaderFieldKey(i); b1XRC`Gy  
if(sHeader!=null) r|e-<t4.9L  
{ .`<@m]m-  
if(sHeader.equals("Content-Length")) SUKxkc(  
{ )Or  .;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :'F}Dy  
break; klgy;jSEr  
} !+)AeDc:j  
} cRd0S*QN2  
else G$0c '9d*(  
break; 'J&f%kx"  
} v[plT2"s  
} :0)3K7Q   
catch(IOException e){e.printStackTrace ();} {j5e9pg1L|  
catch(Exception e){e.printStackTrace ();} @~c6qh  
]ul$*  
/2EHv.e `  
Utility.log(nFileLength); 1i:|3PA~  
jcNT<}k C  
Uy ?  
return nFileLength; *KY=\ %D  
} hQ6a~?f  
3p2P= T  
mbnV[  
//保存下载信息(文件指针位置) iRg7*MQu  
private void write_nPos() =[\s8XH,  
{ DypFl M*  
try{ %>-@K|:gS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U j+j}C  
output.writeInt(nStartPos.length); a22Mufl  
for(int i=0;i<nStartPos.length;i++) b^D$jY  
{ X|0R= n]  
// output.writeLong(nPos); \<}&&SuH  
output.writeLong(fileSplitterFetch.nStartPos); f7h*Vu`>  
output.writeLong(fileSplitterFetch.nEndPos); /!^&;$A'  
} w.,Q1\*rPp  
output.close(); LK6; ? m  
} A;\ 7|'4  
catch(IOException e){e.printStackTrace ();} P=3RLL<l  
catch(Exception e){e.printStackTrace ();} W^3uEm&l!)  
} %sHF-n5P  
E9?ph D  
qd8n2f  
//读取保存的下载信息(文件指针位置) ?bM_q_5  
private void read_nPos() +xc'1id@[  
{ 7eWk7&Xul  
try{ 9j W2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,rJXy_  
int nCount = input.readInt(); !T](Udf  
nStartPos = new long[nCount]; [,2|Flf e  
nEndPos = new long[nCount]; {hln?'  
for(int i=0;i<nStartPos.length;i++) Ig3;E+*>  
{ :qChMU|Y6  
nStartPos = input.readLong(); 1]orUF&_  
nEndPos = input.readLong(); 54 >-  
} :Mm3 gW)  
input.close(); zIP6\u  
} k} ]T;|h]  
catch(IOException e){e.printStackTrace ();} \J+*  
catch(Exception e){e.printStackTrace ();} n,B,"\fw  
} "#(T  
P/EM :  
J|'7_0OAx  
private void processErrorCode(int nErrorCode) F u&EhGm6  
{ L\y;LSTU  
System.err.println("Error Code : " + nErrorCode); 6#IU*  
} /axIIfx-  
G$ _yy:  
s'kDk2r  
//停止文件下载 }%Bl>M  
public void siteStop() ^v.,y3  
{ lA>DS#_  
bStop = true; f!O{%ev  
for(int i=0;i<nStartPos.length;i++) J'N!Omz  
fileSplitterFetch.splitterStop(); sdQkT#%y  
]4;PR("aU  
j"AU z)x  
} @6l%,N<fou  
} D#&q&6P{  
//负责部分文件的抓取 !"8fdSfg w  
**FileSplitterFetch.java gJ2>(k03y  
*/ l NQcYv  
package NetFox; L%>n>w  
R(n^)^?  
=gcM%=*'  
import java.io.*; lFTF ,G  
import java.net.*; o] mD"3_  
2h[85\4  
x3PD1JUf  
public class FileSplitterFetch extends Thread { YZ%Hu)  
J>u 7,  
i hh/sPi  
String sURL; //File URL .BFYY13H  
long nStartPos; //File Snippet Start Position &ZL3{M  
long nEndPos; //File Snippet End Position tK&' <tZh  
int nThreadID; //Thread's ID 5Ri6Z#qm  
boolean bDownOver = false; //Downing is over /z BxJT0  
boolean bStop = false; //Stop identical rXA*NeA3v  
FileAccessI fileAccessI = null; //File Access interface u]vQ>Uu  
me OMq1  
-?(E_^ng  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException r#xg#uoj  
{ )Tk1 QHU  
this.sURL = sURL; 6;|n]m\Vd  
this.nStartPos = nStart; 9 7ql5  
this.nEndPos = nEnd; Z!U)I-x&  
nThreadID = id; F'hHK.tT  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8T(e.I  
} P;k0W>~k  
z )HD`Ho  
i86>]  
public void run() ?.D3'qv  
{ =zyC-;r!  
while(nStartPos < nEndPos && !bStop) 2 !'A:;  
{ n> ^[T[.S  
Q'%PNrN  
W3iZ|[E;  
try{ {'U Rz[g  
URL url = new URL(sURL); EY \H=@A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;\p KDPr  
httpConnection.setRequestProperty("User-Agent","NetFox"); %'[&U#-  
String sProperty = "bytes="+nStartPos+"-"; 1 5A*7|  
httpConnection.setRequestProperty("RANGE",sProperty); _Gu- uuy  
Utility.log(sProperty); n5{Xj:}  
.nyfYa+  
1&e} ms  
InputStream input = httpConnection.getInputStream(); h[PYP5{L  
//logResponseHead(httpConnection); }fKSqB]T-  
PG,_^QGCX  
+"1NC\<*  
byte[] b = new byte[1024]; {l |E:>Q2  
int nRead; T8^5=/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 23h% < ,  
{ 7U"[Gf  
nStartPos += fileAccessI.write(b,0,nRead); ZcaX'5} !S  
//if(nThreadID == 1) 4fe7U=#;Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t*?0D\b 2  
} %JLk$sP9y`  
u?9" jX  
!%c'$f/  
Utility.log("Thread " + nThreadID + " is over!"); clk[/'1  
bDownOver = true; ,mj@sC>  
//nPos = fileAccessI.write (b,0,nRead); ~V$ |i"  
} \|K;-pL  
catch(Exception e){e.printStackTrace ();} _r2J7&  
} ai{Sa U  
} x:QgjK  
;$z$@@WC  
P LueVz  
//打印回应的头信息 uV=Qp1~  
public void logResponseHead(HttpURLConnection con) v'BZs   
{ 9 -rNw?7  
for(int i=1;;i++) 0=K9`=5d0  
{ 4n4?4BEn  
String header=con.getHeaderFieldKey(i); hiUD]5Kp  
if(header!=null) 0@EwM  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qM.bF&&Go  
Utility.log(header+" : "+con.getHeaderField(header)); %DdJ ^qHI  
else kV3 8`s>+  
break; N2w"R{)j\  
} 0C>%LJ8r  
} 5sb\r,kW  
eQ&ZX3*}  
Ry|!pV  
public void splitterStop() 8KRba4[  
{ f/V 2f].  
bStop = true; 7P9=)$(EH  
} ldp%{"ZZ  
L@gWzC~?Q  
/"B?1?qc,=  
} 6qaulwV4t  
ndeebXw*  
46 PoM  
/* 39=1f6I1  
**FileAccess.java :duo#w"K  
*//文件访问(定位,写) =dFv/F/RW  
package NetFox; W]nSR RWco  
import java.io.*; X@f "-\  
$ mI0Bk  
DS'n  
public class FileAccessI implements Serializable{ ~t~-A,1  
qv@$ZLR  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ; k)@DX  
RandomAccessFile oSavedFile; 3:C oZ  
long nPos; *Q,0W:~-  
d.P\fPSD  
u07pq4Ly  
public FileAccessI() throws IOException WoBo9aR  
{ =X.9,$Y  
this("",0); M6}3wM*4  
} rW0FA  
'UYR5Y>  
kbMYMx.[  
public FileAccessI(String sName,long nPos) throws IOException Oj^,m.R  
{ Q_Gi]M9  
oSavedFile = new RandomAccessFile(sName,"rw"); t8dm)s[r8  
this.nPos = nPos; PoT`}-9  
oSavedFile.seek(nPos); QV&D l_  
} 67VT\f  
di>cMS 4 c  
L*~J%7  
public synchronized int write(byte[] b,int nStart,int nLen) xa pq*oj  
{ 1Tm^  
int n = -1; T16{_  
try{ /, !B2  
oSavedFile.write(b,nStart,nLen); jb^N|zb  
n = nLen; oDU ;E  
} g2T -TG'd  
catch(IOException e) [!U?}1YQ  
{ FG) $y[*  
e.printStackTrace (); l@ap]R  
} oD$J0{K6  
>`%'4<I  
J;f!!<l\  
return n; ,Bal  
} b%S62(qP  
1hziXC0WY  
nVI! @qW  
} Q J7L7S  
l!g]a2x*  
$.[#0lCI  
/* pe{; ~-|6  
**SiteInfoBean.java a@0BBihz  
*/ 6%VV,$p  
package NetFox; gw}Mw  
:bC40@  
Z>^pCc\lH  
public class SiteInfoBean { `2PLWo  
Ed ,D8ND  
4M^G`WA}t9  
private String sSiteURL; //Site's URL 1 %,a =,v  
private String sFilePath; //Saved File's Path b/Xbs0q  
private String sFileName; //Saved File's Name ME=/|.}D<  
private int nSplitter; //Count of Splited Downloading File Vl2XDkhq  
)u qA(R>  
Ey4z.s'-l  
public SiteInfoBean() V@\%)J'g  
{//nSplitter的缺省值为5 @`,1:  
//default value of nSplitter is 5 -%I2[)F<  
this("","","",5); B0ndcB-  
} Y]3>7q%  
al[n, u  
X 51Yfr  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) iT)z_  
{ T0]*{k(FR  
sSiteURL= sURL; xSBc-u#< G  
sFilePath = sPath; eVM/uDD  
sFileName = sName; dF~8XYo  
this.nSplitter = nSpiltter; >~Qr  
/mK?E5H'r1  
_Y[jyD1>  
} 56Vb+0J'  
G2^et$<{uU  
4NdN< #Lr  
public String getSSiteURL() 'gt-s547  
{ I'@Ydt2  
return sSiteURL; Q(\4]i< S  
} IEcf  
edK|NOOZ  
D11F.McM  
public void setSSiteURL(String value) $]q8, N|1  
{ Bk+{RN(w  
sSiteURL = value; <$hu   
} (k|_J42[  
is@b&V]  
M_%B|S {  
public String getSFilePath() fks)+L'  
{ bN3#{l-`  
return sFilePath; bl'z<S, '  
} <~)kwq'  
jH6&q~#  
J;prC  
public void setSFilePath(String value) $/7pYl\n  
{ +Lnsr\BA  
sFilePath = value; ku..aG`  
} D91e\|]  
3q?\r` a  
T]?n)L,2  
public String getSFileName() "hy.GWF|*  
{ rgOfNVyJG<  
return sFileName; STJJU]H  
} 5j-]EJb  
 fu9Cx  
<2nZ&M4/s{  
public void setSFileName(String value) 2 6>ZW4Z  
{ U. @*`Fg  
sFileName = value; ?SC[G-b  
} Hp(D);0+)  
o^V(U~m]  
LB.co4  
public int getNSplitter() EFc-foN  
{ g9Yz*Nee<  
return nSplitter; f +hjC  
} "ax..Mh\y  
<u=4*:QE  
|> _!eS\=<  
public void setNSplitter(int nCount) >pr=|$zk=  
{ dqX;#H}h  
nSplitter = nCount; X~xd/M=9^  
} Jx=hJ-FY  
} 2mq$H_  
X7g3  
8Mbeg ,P  
/* ~I(Hc.Q  
**Utility.java 2>l,no39t+  
*/ \t|M-%&)4  
package NetFox; s<]&*e&}?  
-uH#VP{0M  
.uEPnzi  
public class Utility { 8j4z{+'TQ  
1c@} C+F+  
>g;kJe  
public Utility() Ia'ZV7'  
{ n\ Hs@.  
@p|$/Z%R,  
F]I=+T   
} $.:mai  
W k}AmC  
//线程睡眠 X.TI>90{  
public static void sleep(int nSecond) nJbbzQ,e  
{ (S^8UV  
try{ O MX-_\")  
Thread.sleep(nSecond); nL?oTze*p  
} H-p;6C<  
catch(Exception e) K)_WL]RJ.4  
{ 9V.u-^o&  
e.printStackTrace (); \`w4|T  
} O$ HBO  
} z7-k`(l4  
2:LHy[{5  
//日志 O0PJ6:9P  
public static void log(String sMsg) m5D"A D  
{ 9Ok9bC'?8@  
System.err.println(sMsg); J4YBqp  
} vs j3  
RJeSi`19T)  
T,_(?YJW  
public static void log(int sMsg) /(8a~f&%r  
{ Krs2Gre}  
System.err.println(sMsg); 5#E |R  
} x^*1gv $o  
} wl1m*`$  
Yh)Isg|0>  
:L 3&FA   
/* "<i SZ  
**TestMethod.java CD0VfA>Z  
*/ )R sM!}  
package NetFox; Xe+,wW3YF  
LC0d/hM  
s9oO%e<  
public class TestMethod { LG]3hz9^9  
&5t :H 8b  
-xD*tf*  
public TestMethod() aV1lJ ;0  
{ ///xx/weblogic60b2_win.exe %/.a]j!  
try{ ,pBh`av  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); T$= 4O9G  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [\Qr. 2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pA4*bO+  
fileFetch.start(); ]h9!ei [  
} QjPj[c  
catch(Exception e){e.printStackTrace ();} $t-n'Qh^2  
jtm?z c  
#?B%Ja% ;W  
} N:"C+ a(  
~}DQT>7$  
>`jU`bR@  
public static void main(String[] args)  st 'D  
{ gf)t)-E  
new TestMethod(); j 6ut}Uq  
} B%\gkl  
} 5HS~op2n/  
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