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http断点续传简单实现(java)

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/* c1CUG1i  
**SiteFileFetch.java TQjM3Ri=V  
*/ &nXa /XIZ_  
package NetFox; CEMe2~  
import java.io.*; uLK4tQ  
import java.net.*; LNU#NJ^Axt  
] 1:pnd  
ML= :&M!ao  
public class SiteFileFetch extends Thread { OqW (C  
UwQyAD]Ht  
jy kY8;4  
SiteInfoBean siteInfoBean = null; //文件信息Bean 8t$w/#'@  
long[] nStartPos; //开始位置 ~6HaZlBB  
long[] nEndPos; //结束位置 to%n2^^K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 y G{;kJ P  
long nFileLength; //文件长度 !JOM+P:  
boolean bFirst = true; //是否第一次取文件 x[w!buV0\  
boolean bStop = false; //停止标志 g~Hmka_fD1  
File tmpFile; //文件下载的临时信息 sm1(I7y  
DataOutputStream output; //输出到文件的输出流 ^@a|s Sb  
XSDudL  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) __Tg1A  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3ug-cq  
{ _w\A=6=q|  
siteInfoBean = bean; =Kh1 HU.F  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ' 6#en9{L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); FJYc*l  
if(tmpFile.exists ()) UrhSX!g/A>  
{ pZA0Go2!IN  
bFirst = false; .V.x0  
read_nPos(); nxZ[E.-\  
} nTd[-3o  
else wFHbz9|@I  
{ #y4+O;{  
nStartPos = new long[bean.getNSplitter()]; Ki_8g  
nEndPos = new long[bean.getNSplitter()]; cf7UV6D g  
} hCX_^%  
< `/22S"  
'A}@XGE:p  
Sph:OX8  
} sE Rm+x<  
c&rS7%  
@$bEY#*C  
public void run() <Jwx|  
{ >I^_kBa  
//获得文件长度 =SEgv;#KZ~  
//分割文件 mO1r~-~AJ  
//实例FileSplitterFetch {;T7Kg.C  
//启动FileSplitterFetch线程 ~$ FgiW  
//等待子线程返回 UOwEA9q%  
try{ E2Jmo5yJR  
if(bFirst) S~+er{,ht4  
{ |_ u  
nFileLength = getFileSize(); TTSyDl  
if(nFileLength == -1) 1[&V6=n  
{ }kK6"]Tj  
System.err.println("File Length is not known!"); %x2_njDd  
} ]3/_?n-"`  
else if(nFileLength == -2) {0t-Q k  
{ &P,z$H{o@  
System.err.println("File is not access!"); ZNX=]]HM<n  
} 6k@(7Mw8A  
else e71dNL'$  
{ bWe_<'N  
for(int i=0;i<nStartPos.length;i++) m\];.Da  
{ lz-t+LD@ST  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &0='z  
} Pgp`g.$<  
for(int i=0;i<nEndPos.length-1;i++) HLYTt)f}  
{ \ O#6H5F  
nEndPos = nStartPos[i+1]; 6|O2i j-J  
} ;vDjd2@  
nEndPos[nEndPos.length-1] = nFileLength; i4XE26B;e  
} 4EZl (v"f`  
} )8rN   
A/%+AH(  
X4bB  
//启动子线程 0M=U >g)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; M'"@l $[QM  
for(int i=0;i<nStartPos.length;i++) BnL[C:|  
{ S.#IC lV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), km(Mv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ZI0C%c.~  
nStartPos,nEndPos,i); t;?TXAA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f L}3I(VK  
fileSplitterFetch.start(); 42Vz6 k:  
} <.HDv:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q|N/vkqPz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !jIpgs5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", pFZ2(b&  
nEndPos = " + nFileLength); 2Y`C\u  
// fileSplitterFetch[nPos.length-1].start(); @0 mR_\u\  
c2aW4 TX2  
.-[d6Pnw  
//等待子线程结束 i3s,C;7[2  
//int count = 0; L#|, _j=9  
//是否结束while循环 yl#(jb[?1  
boolean breakWhile = false; o_K. +^$  
Z|h&Zd1z  
e_6-+l!f  
while(!bStop) e9 `n@  
{ 1lJY=`8qa  
write_nPos(); M2.Pf s  
Utility.sleep(500); 3,QsB<9Is  
breakWhile = true; {r$n $  
"0&+ `7  
X9YYUnR2  
for(int i=0;i<nStartPos.length;i++) $<~o,e-4  
{ oOU?6nq  
if(!fileSplitterFetch.bDownOver) _eE hIQ9  
{ {);S6F$[3  
breakWhile = false; J!5>8I(_wX  
break; 8)1 k>=  
} ^Iz(V2  
} V\ 7O)g  
if(breakWhile) ;Rz+4<  
break; ZMI!Sl  
etPb^&#$  
EzXGb  
//count++; J=*X%^jX9Z  
//if(count>4) <H,q( :pM  
// siteStop(); PS13h_j  
} _2wU(XYH  
6;:s N8M+1  
xjplJ'jB  
System.err.println("文件下载结束!"); m-M.F9R  
} nisW<Q`uB  
catch(Exception e){e.printStackTrace ();} %p R: .u|  
} dC F!.  
POl[]ni=>  
|Zn |?#F  
//获得文件长度 C|@6rr9TA  
public long getFileSize() "8'aZ.P  
{ |BO!q9633V  
int nFileLength = -1; ]4$t'wI.  
try{ !@r1B`]j+"  
URL url = new URL(siteInfoBean.getSSiteURL()); ?0{8fGM4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KXAh0A?&+  
httpConnection.setRequestProperty("User-Agent","NetFox"); exn Fy-  
h{R>L s  
[|XMR=\>  
int responseCode=httpConnection.getResponseCode(); }=+J&cR  
if(responseCode>=400) ?3x7_=4t@  
{ (}E ] g  
processErrorCode(responseCode); }AZ0BI,TI  
return -2; //-2 represent access is error aMxg6\8  
} ~BS Ip .  
;~2RWj=-  
:z^VI M  
String sHeader; sn4wd:b7%  
@-7h}2P Q  
)YB @6TiD  
for(int i=1;;i++) 6eUM[C.  
{ {GTOHJ2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); E>bK-jG  
//Utility.log(in.readLine()); M_5$y )M  
sHeader=httpConnection.getHeaderFieldKey(i); #`1@4,iC  
if(sHeader!=null) (4hCT*  
{ W!R}eLf@  
if(sHeader.equals("Content-Length")) VSW:h  
{ U X?EOrfJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Jj_ t0"  
break; O,&nCxB]  
} H\zV/1~Y  
} $rb #k{  
else ?8g*"& cn  
break; ?l6NQ;z  
} ^9{mjy0Q  
} "M)kV5v%  
catch(IOException e){e.printStackTrace ();} HI` q!LPv  
catch(Exception e){e.printStackTrace ();} 3rF=u:r7c  
ifA)Ppt<`  
8BL ]]gT-I  
Utility.log(nFileLength); *gq~~(jH  
Z'vic#  
*0K@^Db-  
return nFileLength; QO0#p1fom'  
} q&j4PR{  
<vMdfw"(  
4\cJ}p}LZ{  
//保存下载信息(文件指针位置) IQ${2Dpg[  
private void write_nPos() Znv3h  
{ |KV|x ^fJ  
try{ /M}jF*5N  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 69z,_p$@:  
output.writeInt(nStartPos.length); zdL"PF  
for(int i=0;i<nStartPos.length;i++) #6'x-Z_  
{ &!@7+'])  
// output.writeLong(nPos); q_h=O1W  
output.writeLong(fileSplitterFetch.nStartPos); deRnP$u0  
output.writeLong(fileSplitterFetch.nEndPos); @w%{yzr%  
} b,Z\{M:f;F  
output.close(); =B0#z]qu  
} Gu3# y"a>  
catch(IOException e){e.printStackTrace ();} &YSjwRr  
catch(Exception e){e.printStackTrace ();} d".Xp4}f  
} gPo3jwo$  
=JqKdLH  
7j9X<8 *  
//读取保存的下载信息(文件指针位置) 2MV!@rx  
private void read_nPos() jkzC^aG  
{ %^5|3l3y  
try{ ;;A8TcE '  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Dd3GdG@*~  
int nCount = input.readInt(); :`pgdn  
nStartPos = new long[nCount]; SuO@LroxTB  
nEndPos = new long[nCount]; 7$z]oVbO'  
for(int i=0;i<nStartPos.length;i++) \Ax[/J2aO  
{ "kS(b4^  
nStartPos = input.readLong(); 8?YWE62  
nEndPos = input.readLong(); U{8]TEv  
} B 66-l!xa  
input.close(); -f{NVX\<0  
} 'Ti7}K  
catch(IOException e){e.printStackTrace ();} jjT|@\-u  
catch(Exception e){e.printStackTrace ();} %yVboA1  
} >=T\=y  
&Z.zem?n  
]*M VVzF  
private void processErrorCode(int nErrorCode) >ZE8EL  
{ "@!B"'xg  
System.err.println("Error Code : " + nErrorCode); da'7* &/  
} QR.]?t;1  
{JJq/[j  
Y &G]M  
//停止文件下载 \Q CH.~]  
public void siteStop() I6jDRC0<  
{ ?3I93Bt7  
bStop = true; F!LVyY"w  
for(int i=0;i<nStartPos.length;i++) 8 2EH'C  
fileSplitterFetch.splitterStop(); l]bCt b%_  
ogOUrJ}P  
QSaJb?I  
} wDL dmrB  
} <9BM%  
//负责部分文件的抓取 BEm~o#D  
**FileSplitterFetch.java I^CKq?V?:  
*/ Q>G lA  
package NetFox; 1L4-hYtCj  
~O;'],#Co  
f&n6;N  
import java.io.*; &fIx2ZM[  
import java.net.*; zFR=inI  
-C>q,mDJZ  
iG.qMf.  
public class FileSplitterFetch extends Thread { _#kjiJj *  
y [pU8QSt  
53i7:1[uV  
String sURL; //File URL r8k.I4  
long nStartPos; //File Snippet Start Position :~% zX*   
long nEndPos; //File Snippet End Position }"sZ)FE  
int nThreadID; //Thread's ID |X'Pa9u  
boolean bDownOver = false; //Downing is over  Uu<Tn#nb  
boolean bStop = false; //Stop identical , :10  
FileAccessI fileAccessI = null; //File Access interface Ja*k |Rz~  
'K"7Tex  
.5t|FJ]`$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "G(^v?x:P  
{ _YT9zG  
this.sURL = sURL; 1]yjhw9g  
this.nStartPos = nStart; kOQq+_Y  
this.nEndPos = nEnd; "F$0NYb]I  
nThreadID = id; tW=,o&C=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +Vf39}8  
} B?-~f^*,jG  
a2z1/Nh  
cP]5Qz   
public void run() SU {U+  
{ t$*V*gK{  
while(nStartPos < nEndPos && !bStop) hPM:=@ N$  
{ 0Xke26ga  
T VuDK  
TqZ&X| G  
try{ DaK2P;WP  
URL url = new URL(sURL); jgkJF[t`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #Q6.r.3@x  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]Zj6W9]m  
String sProperty = "bytes="+nStartPos+"-"; r=`]L-}V  
httpConnection.setRequestProperty("RANGE",sProperty); #Fl5]> |  
Utility.log(sProperty); iJr 1w&GL$  
G OzV#  
NY& |:F  
InputStream input = httpConnection.getInputStream(); f:).wi Ld  
//logResponseHead(httpConnection); v4YY6? 4  
<21@jdu3n,  
lwhVP$q}  
byte[] b = new byte[1024]; Z,? T`[4B  
int nRead; --32kuF&(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f"wm]Q59  
{ OFyZY@B-C~  
nStartPos += fileAccessI.write(b,0,nRead); 7wm9S4+|  
//if(nThreadID == 1) e@GR[0~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \N?,6;%xB  
} R24ZjbKL  
(ohza<X;6  
Za&.sg3RG  
Utility.log("Thread " + nThreadID + " is over!"); us:V\V  
bDownOver = true; jW?siQO^  
//nPos = fileAccessI.write (b,0,nRead); L'*P;z7<  
} l$:.bwXXO  
catch(Exception e){e.printStackTrace ();} h /.^iT  
} 5z$>M3  
} %U4w@jp  
Ga%x(1U[&  
,z*-93H1  
//打印回应的头信息 Gz>M`M`[4  
public void logResponseHead(HttpURLConnection con) l5 FM>q  
{ Je5UVf3>2&  
for(int i=1;;i++) \Jcj4  
{ 6*cY[R|q!  
String header=con.getHeaderFieldKey(i); |.s#m^"  
if(header!=null) RCS91[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); f a9n6uT  
Utility.log(header+" : "+con.getHeaderField(header)); cITF=Ez  
else :EX H8n&|  
break; N~w4|q!]  
} mJ>@Dh3>G  
} bhI yq4N  
r%QnV0L^  
U;QN+fF]u  
public void splitterStop() CQLh;W`Dc  
{ XO=UKk+EK  
bStop = true; R m{\ R  
} @rTAbEk{U  
"DW; 6<m  
)k@+8Yfa1p  
} Sb9In_* 0  
$p} /&  
WLb *\  
/* u_5O<UP5  
**FileAccess.java xyoh B#'W  
*//文件访问(定位,写) Gob;dku  
package NetFox; `$X|VAS2  
import java.io.*; CkJU5D  
xSQ0]vE  
4s Vr]p`  
public class FileAccessI implements Serializable{ CD]2a@j {  
wc-ll&0Z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 e|L$e0  
RandomAccessFile oSavedFile; 0'DlsC/`*  
long nPos; S[J=d%(  
;T|y^D  
"/EE$eU  
public FileAccessI() throws IOException *L%i-Wg"  
{ B>^5h?(lt  
this("",0); +UK".  
} )A`Zgg'L7D  
]Tje6i F  
gAx8r-` `  
public FileAccessI(String sName,long nPos) throws IOException U2tsHm.O  
{ h-XMr_F  
oSavedFile = new RandomAccessFile(sName,"rw"); wGqQR)a  
this.nPos = nPos; _t:l:x.;T  
oSavedFile.seek(nPos); a=55bEn  
} '.@'^80iQ  
3b_tK^|'  
%HRFH  
public synchronized int write(byte[] b,int nStart,int nLen) >PsP y.  
{ a?+Ni|+  
int n = -1; !f(aWrw7e6  
try{ :Rs% (Z  
oSavedFile.write(b,nStart,nLen); h=q%h8  
n = nLen; 2C@hjw(  
} sFEkxZi<  
catch(IOException e) /mB'Fn6)  
{ a{lDHk`Wf  
e.printStackTrace (); !lSxBr[dQ  
} c=YJ:&/5&  
b&$ ?.z  
=A6/D    
return n; `0r=ND5.  
} X^tVq..0  
oCLs"L-r{  
3^LSK7.:  
} I5"ew=x#  
M y:9  
CqXD z  
/* -DO*,Eecv  
**SiteInfoBean.java w"CcWng1  
*/ ~3 {C &c  
package NetFox; \ B~9Ue!  
zS Yh ?NB5  
LhZWK^!{S  
public class SiteInfoBean { /H)K_H#|;  
o W)M&$oS  
n'/w(o$&  
private String sSiteURL; //Site's URL :!a9|Fh~  
private String sFilePath; //Saved File's Path :<%q9)aPf`  
private String sFileName; //Saved File's Name VV(>e@Bc4  
private int nSplitter; //Count of Splited Downloading File 9o.WJ   
(K$K;f$"r  
GHHErXT\a  
public SiteInfoBean() qYg4H|6  
{//nSplitter的缺省值为5 vqLC?{i+  
//default value of nSplitter is 5 WUid5e2  
this("","","",5); $'f<4  
} Ae,-. xJ  
&bx;GG\<4  
,L+tm>I  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]E66'  
{ A9! gww  
sSiteURL= sURL; , #yE#8  
sFilePath = sPath; R v9?<]  
sFileName = sName; w5l:^^zF(  
this.nSplitter = nSpiltter; ~U:{~z  
H/_R!G8 \  
r}i<cyL  
} %$j)?e  
EXDtVa Ot  
NyD[9R?  
public String getSSiteURL() D4yJ:ATO&  
{ 7N^9D H{`  
return sSiteURL; e~r%8.Wm  
} iTU 8WWY<  
Xj^6ZJc  
G7k0P-r,0  
public void setSSiteURL(String value) $Yt29AQ  
{ \#5t%t  
sSiteURL = value; M}4%LjD  
} O6P0Am7s  
+dm&XW >  
9?r|Y@xh]  
public String getSFilePath() ~UjFL~K}  
{ I)ub='+&;  
return sFilePath; e-4XNL[F  
} ~R.8r-kD`  
B&0^3iKFi  
b .k J&c  
public void setSFilePath(String value) 65VnH=  
{ p ez^]I  
sFilePath = value; %3'4QmpR  
} C #ng`7 q  
S .rT5A[  
kZ+nL)YQ#  
public String getSFileName() ^RG6h  
{ : j&M&+  
return sFileName; }N5>^y  
} 4NL Tt K  
"GP!]3t  
-zg,pK$+  
public void setSFileName(String value) CGIcuHp  
{ $]4^ENkI  
sFileName = value; ll {jE  
} e#K =SV!H  
H,qIHQW#  
_`WbR&d2Id  
public int getNSplitter() * B,D#;6  
{ `G\uTCpk  
return nSplitter; 9|dgmEd  
} PYqx&om  
4VPL -":6  
@`aR*B  
public void setNSplitter(int nCount) ^Sx 0t  
{  IpY  R  
nSplitter = nCount; g^(wZ$NH  
} 9iWDEk  
} $j^Jj  
goi.'8M|/b  
(,PO(  
/* JxI}#iA  
**Utility.java L,.Ae i9  
*/ .MuS"R{y  
package NetFox; $ud5bT{n  
DW@PPvfs  
y]9 3z!#Z  
public class Utility { m/n_e g  
dg 0`0k  
z %` \p  
public Utility() T%K(opISc(  
{ XJsHy_6  
=)m2u2c M  
UiA\J  
}  ~%_$e/T  
h@FDP#H  
//线程睡眠 xh[Mmq/R  
public static void sleep(int nSecond) ^ng#J\  
{ zcD&xoL\H  
try{ 9H ?er_6Yf  
Thread.sleep(nSecond); ?hvPPEJf  
} j$^3  
catch(Exception e) * 7.!"rb8A  
{ xf<D5 olZ  
e.printStackTrace (); aM?Xi6 U5  
} g5R2a7  
} on $?c  
|\2z w _o  
//日志 /ZZo`   
public static void log(String sMsg) >|!F.W  
{ E#r6e+e1Q%  
System.err.println(sMsg); tYiK#N7  
} w"$CV@AJ  
R6] /g  
`GS!$9j  
public static void log(int sMsg) 5Fm.] /  
{ WM NcPHcj  
System.err.println(sMsg); pj&vnX6O^  
} EP&iG%(k  
} 64>E|w  
jDI O,XuF  
\-N 4G1  
/* 7 }>j [  
**TestMethod.java Rtw^ lo  
*/ _Xd,aLoo  
package NetFox; AU}e^1h  
\v{tK;  
Q.#@xaX'{`  
public class TestMethod { u_s  
7kO5hlKeo  
-}1S6dzr  
public TestMethod() ;$l!mv 7  
{ ///xx/weblogic60b2_win.exe L=3^A'|  
try{ @26H;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); AZt~ \qf  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `o yz"07m  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ct=|y(_  
fileFetch.start(); 7(^<Z5@  
} G!T)V2y  
catch(Exception e){e.printStackTrace ();} zg2A$Fd[j  
Oyhl*`-*t  
[>::@[  
} _aL:XKM  
|;ycEB1  
:XcU@m  
public static void main(String[] args) 9d^o2Y o  
{ #ebT$hf30  
new TestMethod(); @FIR9XJ  
} ug0[*#|Y  
} T!eeMsI  
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