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http断点续传简单实现(java)

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/* v0~'`*|&  
**SiteFileFetch.java 7/p&]0w  
*/ D{%l 4og  
package NetFox; HM'P<<  
import java.io.*; /h)_Q;35S;  
import java.net.*; FiN^}Kh  
Idq &0<I  
jacp':T  
public class SiteFileFetch extends Thread { 2WKYf0t  
2`D1cX  
* $  
SiteInfoBean siteInfoBean = null; //文件信息Bean )qg cz<p?W  
long[] nStartPos; //开始位置 X\?PnD`,  
long[] nEndPos; //结束位置 hJuR,NP  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 AFd3_>h  
long nFileLength; //文件长度 HnDz4eD  
boolean bFirst = true; //是否第一次取文件 oCl $ 0x  
boolean bStop = false; //停止标志 J$9`[^pV  
File tmpFile; //文件下载的临时信息 PS" ,  
DataOutputStream output; //输出到文件的输出流 Ro&s\T+d  
4$j7DJ8dj  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) v[3QI7E3  
public SiteFileFetch(SiteInfoBean bean) throws IOException zz4TJ('  
{ pN-l82]'  
siteInfoBean = bean; m :6.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J(k\Pz*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); X/=*o;":  
if(tmpFile.exists ()) n^HKf^]  
{ M Y2=lT  
bFirst = false; a>3#z2#  
read_nPos(); O WJv<3  
} U Bo[iZ|%  
else F\!Va  
{ -r.Qy(}p  
nStartPos = new long[bean.getNSplitter()]; .7h:/d Y:  
nEndPos = new long[bean.getNSplitter()]; 7Ya4>*B  
} Ya%-/u  
3WOm`<  
#FAy ]7/O  
/S}4J"  
} R2]2#3`  
jH 4,-  
9 n(.v}  
public void run() k<bA\5K  
{ ?3f-" K_r  
//获得文件长度 L7\ rx w  
//分割文件 'U9l  
//实例FileSplitterFetch M_<? <>|  
//启动FileSplitterFetch线程 X?2ub/Nr#Y  
//等待子线程返回 D*!UB5<>/t  
try{ I}?+>cf  
if(bFirst) 5_|Sm=  
{ XZ|%9#6  
nFileLength = getFileSize(); G*oqhep  
if(nFileLength == -1) (%bqeI!ob  
{ )D_\~n/5  
System.err.println("File Length is not known!"); 5:oteNc3  
} X9|={ng)g#  
else if(nFileLength == -2) +,"O#`sy<  
{ S:.Vt&+NJ  
System.err.println("File is not access!"); <)f1skJsP  
} bgi B*`z  
else 6RA4@bIG  
{ Ys+2/>!  
for(int i=0;i<nStartPos.length;i++) y4j J&  
{ RM5$O+"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); IB'gY0*  
} |%V-|\GJ~j  
for(int i=0;i<nEndPos.length-1;i++) g>@T5&1q*  
{ O]| T !  
nEndPos = nStartPos[i+1]; l\Q--  
} W8@o7svrh  
nEndPos[nEndPos.length-1] = nFileLength; M%U1?^j8  
} .B9i`)0  
} | Ns-l (l  
E`M, n ,  
R#K,/b%SV  
//启动子线程 C0 RnBu  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; KOYU'hw  
for(int i=0;i<nStartPos.length;i++) p3Ey[kURp  
{ >Y3ZK{b  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &8w MGahp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), j'2:z#  
nStartPos,nEndPos,i); s-S#qGZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bhqV2y*'  
fileSplitterFetch.start(); a 8(mU%  
} +NM`y=@@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >EVY,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pA~eGar_J  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +\Zr\fOe|%  
nEndPos = " + nFileLength); 4s <|8   
// fileSplitterFetch[nPos.length-1].start(); "DpgX8lG_  
D^\gU-8M  
<w9<G  
//等待子线程结束 gwAZ2w  
//int count = 0; [M;B 9-2$  
//是否结束while循环 K6..N\7  
boolean breakWhile = false; eG\|E3Cb9  
OYbgt4  
r_p4pxs  
while(!bStop) 9i8 ~  
{ 54^2=bp  
write_nPos(); OG!+p}yD]  
Utility.sleep(500); W%&[gDp  
breakWhile = true; Z(~v{c %<  
dPVl\<L1  
HZ_,f"22  
for(int i=0;i<nStartPos.length;i++) M%aA1!@/  
{ E U# M.  
if(!fileSplitterFetch.bDownOver) hFiJHV  
{ v\#1&</qd^  
breakWhile = false; mO?yrM *  
break; :m{;<LRV  
} Bh%Yu*.f  
} ah8xiABa  
if(breakWhile) d i;Fj  
break; HW"';M%  
u3VSS4RG%  
d[t+iBP;)  
//count++; xGBp+j1H  
//if(count>4) vgyv~Px]AW  
// siteStop(); A4|L;z/A[h  
} H[;\[ 3  
m })EYs1  
DV6B_A{kI  
System.err.println("文件下载结束!"); kJfMTfl,  
} Jh6 z5xUV  
catch(Exception e){e.printStackTrace ();} 1>"Yw|F-|3  
} aj\ zc I  
Wh7}G   
5(qc_~p^  
//获得文件长度 B=,j$uH  
public long getFileSize() .!><qV g  
{ IT5a/;J  
int nFileLength = -1; =D}]|ie  
try{ (& =gM  
URL url = new URL(siteInfoBean.getSSiteURL()); =0" Zse,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6M)4v{F  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]?/7iM  
:jP4GCxU|  
%s(Ri6R&  
int responseCode=httpConnection.getResponseCode(); D'UYHc {  
if(responseCode>=400) ;bh[TmQTJ  
{ uJg|  
processErrorCode(responseCode); [\|p~Qb)s  
return -2; //-2 represent access is error P&2/J%@zG  
} (vXes.|+t  
y(2FaTjM  
j3kcNb  
String sHeader; 4w)aAXK  
Q!&@aKl  
$,&3:ke1  
for(int i=1;;i++) nN|1cJ'.Fk  
{ `{ 6K~(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); jeLC)lQ*  
//Utility.log(in.readLine()); {YT@$K]w,  
sHeader=httpConnection.getHeaderFieldKey(i); !92zC._  
if(sHeader!=null) c1CUG1i  
{ mY& HK)  
if(sHeader.equals("Content-Length")) [$+N"4  
{ &nXa /XIZ_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); CEMe2~  
break; Ga9^+.j  
} 7L"Pe'Hw  
}  +bC=yR  
else r'/H3  
break; x]X!nx6G  
} {r.yoI4e  
} 9[7Gxmf  
catch(IOException e){e.printStackTrace ();} So^;5tG  
catch(Exception e){e.printStackTrace ();} l A1l  
`VzjXJw  
ybNy"2Wk  
Utility.log(nFileLength); /E|Ac&Qk  
7Ns1b(kU  
_1sjsGp>  
return nFileLength; /#]4lFk:h  
} b+DBz}L4  
`N,q~@gL  
1TIP23:  
//保存下载信息(文件指针位置) d#OE) ,`  
private void write_nPos() d_r1 }+ao  
{ ,FP<# 0F*a  
try{ ,vE)/{:d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <T0+-]i  
output.writeInt(nStartPos.length); !U?Z<zh  
for(int i=0;i<nStartPos.length;i++) OY?x'h  
{ ]!=,8dY  
// output.writeLong(nPos); D$W09ng-  
output.writeLong(fileSplitterFetch.nStartPos); tc2e)WZP  
output.writeLong(fileSplitterFetch.nEndPos); N*CcJp{Q  
} lgL|[ik`  
output.close(); n\x@~ SzrX  
} JF%_8Ye5  
catch(IOException e){e.printStackTrace ();} M6mJ'Q482  
catch(Exception e){e.printStackTrace ();} ZY Ci&l  
} p~!UE/V  
fSL'+l3  
7yDWcm_y  
//读取保存的下载信息(文件指针位置) G$HXc$OY  
private void read_nPos() /GQN34RD  
{ JXa5snh{h  
try{ LaolAqU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S7fX1y[  
int nCount = input.readInt(); ]= EYju@  
nStartPos = new long[nCount]; @UG%B7  
nEndPos = new long[nCount]; +LEU|#  
for(int i=0;i<nStartPos.length;i++) @|hn@!YK  
{ f(r=S Xa*  
nStartPos = input.readLong(); )t#v55M  
nEndPos = input.readLong(); ja_.{Zv  
} [$bK%W{f  
input.close(); UW?(-_8  
} =Co[pt  
catch(IOException e){e.printStackTrace ();} q0a8=o"|  
catch(Exception e){e.printStackTrace ();} s;[OR  
} 0K *|B.O  
0qPbmLMK  
:Q@qR((&o  
private void processErrorCode(int nErrorCode) )>X C_ R  
{ r`8>@2sW1  
System.err.println("Error Code : " + nErrorCode); /eI]!a  
} ET[vJnReC  
8:=EA3  
hfBZ:es+  
//停止文件下载 NUvHY:  
public void siteStop() *Mg. * N  
{ [Jjb<6[o  
bStop = true; ;94e   
for(int i=0;i<nStartPos.length;i++) 3tZC&!x?  
fileSplitterFetch.splitterStop(); !eH9LRp  
(*CGZDg  
w.2[Xx~  
} 9jC>OZ0s  
} MS~|F^g  
//负责部分文件的抓取 %9qG|A,cA  
**FileSplitterFetch.java F6$QEiDu@  
*/ J_H=GHMp}  
package NetFox; e~+VN4D&b>  
8FmRD  
Up/s)8$.  
import java.io.*; E7K(I ?  
import java.net.*; NGYUZ\m  
M&/([ >Q  
|~y>R#u8pm  
public class FileSplitterFetch extends Thread { 6*({ZE  
CI~P3"`]  
b# RTHe&X  
String sURL; //File URL }0 BKKU+  
long nStartPos; //File Snippet Start Position :{YOJDtR  
long nEndPos; //File Snippet End Position <Z -d5D>  
int nThreadID; //Thread's ID 1l(_SD;90t  
boolean bDownOver = false; //Downing is over u*aFWl]=  
boolean bStop = false; //Stop identical  >>nt3q  
FileAccessI fileAccessI = null; //File Access interface e7cqm*Qi  
P0 va=H  
+F9)+wT~;q  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4 )U,A~ !  
{ 0bt"U=x4  
this.sURL = sURL; Y\sSW0ZX  
this.nStartPos = nStart; Z^ e?V7q  
this.nEndPos = nEnd; %v_w"2x;  
nThreadID = id;  @o g&l;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 JQp::,g  
} ,vnHEY&  
<1L?Xhoc6  
+frkC| .  
public void run() xMb)4cw}  
{ 64hl0'67y  
while(nStartPos < nEndPos && !bStop) 9~En;e  
{ !}TZmwf'  
jYv`kt  
'^!1AGF  
try{ a IA9rn  
URL url = new URL(sURL); eVVm"96Q.;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xXJl Qbs  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9MmAoLm  
String sProperty = "bytes="+nStartPos+"-"; *&m{)cTs  
httpConnection.setRequestProperty("RANGE",sProperty); '|9fDzW"]  
Utility.log(sProperty); `h:$3a:5  
J'%  
b&i0)/;  
InputStream input = httpConnection.getInputStream(); nVp*u9]  
//logResponseHead(httpConnection); NFEF{|}BM  
-S ASn  
$GR 3tLzK:  
byte[] b = new byte[1024]; RJz$$,RU  
int nRead; h5x_Vjj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #:Tb(R   
{ G/w&yd4  
nStartPos += fileAccessI.write(b,0,nRead); #})OnM^],  
//if(nThreadID == 1) M u>G gQSZ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w,<nH:~  
} xux j  
 bK7j"  
ZP]l%6\.  
Utility.log("Thread " + nThreadID + " is over!"); <ah!!  
bDownOver = true; .sO.Y<- fl  
//nPos = fileAccessI.write (b,0,nRead); %B ,>6 `[  
} h^tU*"   
catch(Exception e){e.printStackTrace ();} xw)$).yc  
} ex- 0@  
} Yb~[XS |p  
/hojm6MM  
>sUavvJ~x  
//打印回应的头信息 +~E;x1&'  
public void logResponseHead(HttpURLConnection con) |fJpX5W-l  
{ *G<K@k  
for(int i=1;;i++) S:*.,zC  
{ ?dJ[? <aG  
String header=con.getHeaderFieldKey(i); 6zJ<27  
if(header!=null) h7}D//~p  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <vP{U  
Utility.log(header+" : "+con.getHeaderField(header)); g.& n X/  
else %LH~Im=  
break; vw;GbQH(  
} xcF:moL  
} VdVUYp  
*kliI]B F]  
J<<Ph  
public void splitterStop()  <|Pw*L$  
{ x9,X0JO  
bStop = true; l f<?k  
} &L88e\ c+  
zNu>25/)(  
0#gu7n|J  
} KfSI6 Y _  
vS!%!-F  
7_HJ|QB  
/* Y5 BWg  
**FileAccess.java O0"u-UX{  
*//文件访问(定位,写) : J3_g<@  
package NetFox; GW]b[l  
import java.io.*; WSt&?+Y  
({GN.pC(  
3X0"</G6  
public class FileAccessI implements Serializable{ G,VTFM6  
J FYV@%1~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <"93  
RandomAccessFile oSavedFile; \c"{V-#o\  
long nPos; %Km^_JM  
-v '|#q  
$P9'"a)Lm  
public FileAccessI() throws IOException yX^/Oc@j  
{ Rh[%UNl  
this("",0); @Kx@ 2#~b  
} w:|BQ,  
lWVvAoe  
1ZUmMa1(  
public FileAccessI(String sName,long nPos) throws IOException Rl. YF+YH  
{ p~n62(  
oSavedFile = new RandomAccessFile(sName,"rw"); B4hT(;k  
this.nPos = nPos; [VD)DO5  
oSavedFile.seek(nPos); 4x`.nql  
} hSg4A=y  
"sM 3NY  
*J ]2"~_.  
public synchronized int write(byte[] b,int nStart,int nLen) Ju0W  
{ F8c^M</  
int n = -1; yX-h|Cr"  
try{ s+EJXox w  
oSavedFile.write(b,nStart,nLen); H pZD^h?L  
n = nLen; MJ=(rp=YU9  
} _iJ8*v 8A  
catch(IOException e) jD`p;#~8  
{ 9S .J%*F7  
e.printStackTrace (); ;tBc&LJ?  
} WOv m%sX  
{^Y0kvnd  
8P kw'.r  
return n; $KmhG1*s  
} #RJFJb/  
ai3wSUYJi  
i9QL}d  
} '@{'T LMCi  
2feiD?0  
3M?vK(zG>P  
/* c]u^0X?&  
**SiteInfoBean.java "JH / ODm  
*/ [m}58?0~x  
package NetFox; da'7* &/  
QR.]?t;1  
M%\=Fb  
public class SiteInfoBean { \Q CH.~]  
<b5J"i&m  
4v=NmO }  
private String sSiteURL; //Site's URL \Y>!vh X  
private String sFilePath; //Saved File's Path 3I" <\M4x  
private String sFileName; //Saved File's Name yY 3Mv/R  
private int nSplitter; //Count of Splited Downloading File 6r|BiHP  
=GP~h*5es  
NoR=:Q 9e  
public SiteInfoBean() OdZLJt?g  
{//nSplitter的缺省值为5 g[#4`Q<.  
//default value of nSplitter is 5 Zx1I&K\Cd  
this("","","",5); (_9cL,v  
} nVO|*Bnf)  
@CxXkR  
e5 "?ol0  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^Hdru]A$2  
{ UC u4S >  
sSiteURL= sURL; /+11`B09  
sFilePath = sPath; KMhEU**  
sFileName = sName; YgeU>I|v  
this.nSplitter = nSpiltter; h rksPK"s2  
A.5N<$l  
.y)Y20=o!  
} NV[_XXTv7  
>h[ {_+  
0c pI2  
public String getSSiteURL() |?kZfr&9q  
{ "1-|ahW  
return sSiteURL; ThvVLK  
} 3RW3<n  
tW=,o&C=  
AXQG  
public void setSSiteURL(String value) RfZZqe U  
{ G;'=#c ^  
sSiteURL = value; kY$vPHZpN  
} &ND8^lR=Y;  
p5`d@y\hj  
{eQ')f  
public String getSFilePath() dV:vM9+x  
{ /IkSgKJiz\  
return sFilePath; %.zcE@7*  
} ^<}>]F_  
A18&9gY  
PGj?`y4  
public void setSFilePath(String value) bSKe@4C  
{ ]xYm@%>6  
sFilePath = value; X-Q;4M-CJ  
} 1>$}N?u:T  
`4&a"`&$  
9uRs@]i  
public String getSFileName() lwhVP$q}  
{ Z,? T`[4B  
return sFileName; --32kuF&(  
} w|;kL{(W  
7wm9S4+|  
_kJ?mTk  
public void setSFileName(String value) p?#cn   
{ fFBD5q(n  
sFileName = value; c'678!r9 P  
} Za&.sg3RG  
W8/8V,  
S]P80|!|  
public int getNSplitter() 0D\b;ju<  
{ =N +Ou5D  
return nSplitter; H=f'nm]dQ  
} 5z$>M3  
M< T[%)v  
rLy <3  
public void setNSplitter(int nCount) 7n_'2qY  
{ ZgXn8O[a  
nSplitter = nCount; T9N&Nh7 3  
} Ao%;!(\I%  
} `2j \(N,  
nCj_4,O  
~MgU"P>  
/* e/h2E dY  
**Utility.java ?;//%c8,.  
*/ TDMyZ!d  
package NetFox; WC?}a^ 8  
:=<0Z1S  
e2onR~Cf  
public class Utility { 9Xr@ll  
RZV8{  
nhUL{ER  
public Utility() ^J([w~&  
{ uAWmg8  
gEE6O%]g  
CUS^j  
} z_jTR[dY  
@\!9dK-W  
//线程睡眠 icX$<lD  
public static void sleep(int nSecond) 6L2Si4OGjG  
{ vfh0aW-O  
try{ K]b_JDEk  
Thread.sleep(nSecond); a zUEp8`|  
} NWGSUUa  
catch(Exception e) /f:)I.FUm  
{ [~ Wiy3n  
e.printStackTrace (); `F#<qZSR  
} R]-$]koQO  
} NW$C1(oT  
OZw<YR  
//日志 7\q_^  
public static void log(String sMsg) 05|,-S  
{ wc-ll&0Z  
System.err.println(sMsg); ql Uw;{;p  
} 7jb{E+DrG  
B Bub'  
Qe~2'Hw#9  
public static void log(int sMsg) Qoj}]jve  
{ 8Jz/'  
System.err.println(sMsg); a-`OE"  
} is3nLm(  
} %Ps DS  
QSn%~o05  
O$><E8q  
/* t*fG;YOg  
**TestMethod.java +3c!.] o;  
*/ x bG'![OX  
package NetFox; wGqQR)a  
_t:l:x.;T  
a=55bEn  
public class TestMethod { '.@'^80iQ  
U#B,Q6~  
n&. bs7N2  
public TestMethod() T4W"!4[  
{ ///xx/weblogic60b2_win.exe jU#/yM "Y  
try{ Z66b>.<8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kXj%thDx  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); IZm_/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); iwHy!Vi-5  
fileFetch.start(); _HT*>-B  
} 0I.9m[<Fc  
catch(Exception e){e.printStackTrace ();} I6]|dA3G  
g5EdW=Dt,  
0d-w<lg9  
} b}G4eXkuj  
a<.7q1F  
>.D0McQg  
public static void main(String[] args) ;w(]z  
{ <JA`e+Bi  
new TestMethod(); BO5gwvyI  
} @-z#vJ5Qe{  
} QK5y%bTSA  
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