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http断点续传简单实现(java)

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/* < Gr9^C  
**SiteFileFetch.java m !#_CQ:  
*/  : cFF  
package NetFox; K4j@j}zK9I  
import java.io.*; ?_VRfeztw  
import java.net.*; W *YW6  
<TI3@9\qXE  
A#Xj]^-*  
public class SiteFileFetch extends Thread { B;eW/#`  
3AvVU]@&Z@  
ZJ^s}  
SiteInfoBean siteInfoBean = null; //文件信息Bean 6RH/V:YY  
long[] nStartPos; //开始位置 Sdgb#?MR|  
long[] nEndPos; //结束位置 UskZ%J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 qPsyqn?Y|  
long nFileLength; //文件长度 *Jb_=j*)  
boolean bFirst = true; //是否第一次取文件 }l.KpdRT2  
boolean bStop = false; //停止标志 jEZ "  
File tmpFile; //文件下载的临时信息 davvI$TA  
DataOutputStream output; //输出到文件的输出流 5\VxXiy 0  
(-bRj#  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) +yth_9  
public SiteFileFetch(SiteInfoBean bean) throws IOException XK1fHfCEa  
{ LPq2+:JpS  
siteInfoBean = bean; 4w@v#H@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); DeA@0HOxh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); r k@UsHy  
if(tmpFile.exists ()) !loO%3_)  
{ ?^U c=  
bFirst = false; yHl@_rN sC  
read_nPos(); 9^oo-,Su_  
} ll_}& a0G  
else =Wj{]&`  
{ E\w+kAAf  
nStartPos = new long[bean.getNSplitter()]; HH7[tGF  
nEndPos = new long[bean.getNSplitter()]; pNuqT*  
} Hr8\QgD<4  
9 >%+bA(  
:#Ty^-"]1  
U%L -NMe  
} 7O:"~L  
n9DbiL1{  
}bp.OV-+  
public void run() T\jAk+$Jo  
{ S:#e8H_7m]  
//获得文件长度 .U<F6I:<md  
//分割文件 B n{)|&;  
//实例FileSplitterFetch Z^<Sj5}6  
//启动FileSplitterFetch线程 ):S!Nl  
//等待子线程返回 am2a#4`  
try{ )]wuF`  
if(bFirst) 691G15  
{ *y{+W   
nFileLength = getFileSize(); A9t8`|1"%H  
if(nFileLength == -1) p(.N(c  
{ o,J^ e_  
System.err.println("File Length is not known!"); lO[E[c G  
} Y5n>r@ )m  
else if(nFileLength == -2) 5.dl>,  
{ b) Ux3PB  
System.err.println("File is not access!"); XwtAF3oz  
} I :@|^PYw  
else [NL -!  
{ hl**zF  
for(int i=0;i<nStartPos.length;i++) W=3? x  
{ $.9 +{mz  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0TmZ*?3!4  
} T!(sZf  
for(int i=0;i<nEndPos.length-1;i++) * .o"ZVl  
{ w]}f6VlEl  
nEndPos = nStartPos[i+1]; ;7L;  
} C;ptir1G;  
nEndPos[nEndPos.length-1] = nFileLength; /eb-'m  
} 7/ t:YBR  
} cN5"i0xk  
QAi1,+y]7w  
bf(+ldq  
//启动子线程 12-EDg/1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6P^hN%0  
for(int i=0;i<nStartPos.length;i++) e+{BJN vz  
{ 0X#+#[W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qW3x{L$c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bLco:-G1E1  
nStartPos,nEndPos,i); L?Cjo4xS  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NZP7r;u  
fileSplitterFetch.start(); n>S2}y  
} KJX>DL 9\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zQ_z7FJCB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7VY8CcL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2qjyFTT  
nEndPos = " + nFileLength); %0zS  
// fileSplitterFetch[nPos.length-1].start(); ` .$&T7  
 HD H  
}2=hd..  
//等待子线程结束 Cdmy.gx^  
//int count = 0; _N@(Y:  
//是否结束while循环 [[X+P 0`r  
boolean breakWhile = false; =W<[Fe3  
zIm-X,~I$  
GL`tOD:P"  
while(!bStop) \?d TH:v/E  
{ [4: Yi{>  
write_nPos(); *E7R(#,yC  
Utility.sleep(500); _@K YF)  
breakWhile = true; }#bZ8tm&  
3daC;;XO  
&oEyixe  
for(int i=0;i<nStartPos.length;i++) |EEi&GOR(y  
{ O J>iq@ >  
if(!fileSplitterFetch.bDownOver) kV+ R5R  
{ {Zl4C;c  
breakWhile = false; }uiPvO+&p  
break; UKj`_a6  
} g>T  
} B:nK)"{  
if(breakWhile) /B[}I}X  
break; ]'UgZsJ  
t\%%d)d9  
^)<w*iqBD  
//count++; -N4z-ozhC  
//if(count>4) {=iyK/Uf  
// siteStop(); ?BsH{Q RYQ  
} 4 4`WYK l  
?;RD u[eD  
P5P< "  
System.err.println("文件下载结束!"); yW`e |!  
} }hq^+fC?  
catch(Exception e){e.printStackTrace ();} lRH0)5`  
} `x2,;h!:)N  
/=/ HB  
ZPvf-Pq Jl  
//获得文件长度 nALnB1  
public long getFileSize() ,5w]\z  
{ ~j]dct7  
int nFileLength = -1; y@aKNWy}$  
try{ #Qsk}Gv  
URL url = new URL(siteInfoBean.getSSiteURL()); ^Et ,TF\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b!,ja?  
httpConnection.setRequestProperty("User-Agent","NetFox"); x=vK EyS@  
yKlU6t&` G  
0e\y~#-  
int responseCode=httpConnection.getResponseCode(); 8JP6M!F#  
if(responseCode>=400) QoWR@u6a  
{ RJwb@r<v  
processErrorCode(responseCode); wE4;Rk1  
return -2; //-2 represent access is error Bj8<@~bX:L  
} r,"7%1I  
03F3q4"  
r@Nl 2  
String sHeader; _aY.  
l1DI*0@  
Q.1XP  
for(int i=1;;i++) UO1$UF! QC  
{ U3+A MVnB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -$9~xX  
//Utility.log(in.readLine()); ]zcV]Qj$~  
sHeader=httpConnection.getHeaderFieldKey(i); F+3!uWUK  
if(sHeader!=null) qw2)v*Fn  
{ VfRs[ 3Q  
if(sHeader.equals("Content-Length")) 2m_H*1 HJ  
{ PLdf_/]-   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0Nt%YP  
break; =E1tgrW  
} 8m|x#*5fQl  
} Yw1Y-M  
else 7PA=)a\  
break; ?Nu#]u-  
} KX=/B=3~  
} s&0*'^'O[S  
catch(IOException e){e.printStackTrace ();} /k) NP  
catch(Exception e){e.printStackTrace ();} F@EZ;[  
%UBPoq  
,8~dz  
Utility.log(nFileLength); A(NEWO  
nSS}%&a:LX  
a}w&dE$!-  
return nFileLength; C[g&F 0 6  
} ]o `4Z"  
7> )l{7  
TG?fUD V  
//保存下载信息(文件指针位置) g4Bg6<;  
private void write_nPos() gkLr]zv  
{ B]i+,u  
try{ TD%WJ9K\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \wTW?>o Z  
output.writeInt(nStartPos.length); r &=r/k2  
for(int i=0;i<nStartPos.length;i++) <9 T [yg  
{  *6'_5~G  
// output.writeLong(nPos); u$\Tg3du2  
output.writeLong(fileSplitterFetch.nStartPos); h%u? lW  
output.writeLong(fileSplitterFetch.nEndPos); R4yJ.f  
} HaS[.&\S0  
output.close(); Of!|,2`(  
} 80cm6?,xu  
catch(IOException e){e.printStackTrace ();} f&f[La  
catch(Exception e){e.printStackTrace ();} u"eZa!#  
} 31H|?cg<  
-)<JBs>  
b\H/-7<  
//读取保存的下载信息(文件指针位置) WI%zr2T  
private void read_nPos() gr[D!D >  
{ WtMcI>4w  
try{ :LG}yq^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  PVS\,  
int nCount = input.readInt(); 5QNBB|X@  
nStartPos = new long[nCount]; ^j1Gmv)  
nEndPos = new long[nCount]; 6CCZda@  
for(int i=0;i<nStartPos.length;i++) Idt@Hk5<&  
{ x[zKtX  
nStartPos = input.readLong(); zp}yiE!bl  
nEndPos = input.readLong(); `;R|V  
} l[:^TfB  
input.close(); f45x%tha%  
} zaQ$ Ht  
catch(IOException e){e.printStackTrace ();} \t[ hg  
catch(Exception e){e.printStackTrace ();} 5B_-nYJDt  
} bwv/{3G,Ys  
MA l{66  
@DRfNJ}  
private void processErrorCode(int nErrorCode) 8s\8`2=  
{ ,%& LG],6  
System.err.println("Error Code : " + nErrorCode); 9_I[o.q   
} V7qCbd^>XJ  
2&3eAJC  
g9RzzE!  
//停止文件下载 bf&.rJ0  
public void siteStop() e-YGuWGN7  
{ vy>];!Cu  
bStop = true; wR`w@ 5,d  
for(int i=0;i<nStartPos.length;i++) h'z+8X_t  
fileSplitterFetch.splitterStop(); ]0at2  
cN0~;!{i  
~GsH8yA_P  
} /S-/SF:>g  
} 'M]CZ}  
//负责部分文件的抓取 lyMJW }T+>  
**FileSplitterFetch.java eUGm ns  
*/ QH~8 aE_i  
package NetFox; *+4>iL*:  
^H@!)+ =  
;@h'Mb  
import java.io.*; "RR./e)h  
import java.net.*; I\F=s-VVY  
8 RzF].)  
Uv W:#  
public class FileSplitterFetch extends Thread { ePIly)=X  
Z`0r]V`Ys  
Huug_E+  
String sURL; //File URL ,& \&::R  
long nStartPos; //File Snippet Start Position wd2P/y42;;  
long nEndPos; //File Snippet End Position 4q@9  
int nThreadID; //Thread's ID ys~p(  
boolean bDownOver = false; //Downing is over sk%:Sp  
boolean bStop = false; //Stop identical XQ+-+CD  
FileAccessI fileAccessI = null; //File Access interface ps{&WT3a  
Y`[HjS,  
^| a&%wxA  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  5Fl  
{ 2yQ;lQ`  
this.sURL = sURL; f(9$"Vi  
this.nStartPos = nStart; T{v<  
this.nEndPos = nEnd; ;{F;e)${M  
nThreadID = id; o+6^|RP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?L ~=Z\H  
} K_w0+oY a  
@zVBn~=i  
=c5 /cpZ^  
public void run() s/p>30Fg  
{ u0 'pR# m|  
while(nStartPos < nEndPos && !bStop) n<"a+TTU  
{ J?HZ,7X:  
S|u1QGB  
Ow&'sR'CX  
try{ {H7$uiq3:B  
URL url = new URL(sURL); &&QDEDszp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %]= 'Uv^x  
httpConnection.setRequestProperty("User-Agent","NetFox"); S92 !jp/  
String sProperty = "bytes="+nStartPos+"-"; w1!\L_::Y  
httpConnection.setRequestProperty("RANGE",sProperty); N%M>,wT  
Utility.log(sProperty); lG^mW \ O  
(^@;`8Dy8  
*7D$;?"  
InputStream input = httpConnection.getInputStream(); Bbe/w#Z  
//logResponseHead(httpConnection); ;r@R (Squ  
/EAQ.vxI  
y[7xK}`_  
byte[] b = new byte[1024]; ?RjKP3P  
int nRead; iJp!ROI  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) MdTd$ 4J3  
{ @SMy0:c:  
nStartPos += fileAccessI.write(b,0,nRead); P A+e= %  
//if(nThreadID == 1) Pt)}HF|u  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4>ce,*B1  
} 3E2.v5*  
7!QXh;u  
h/y}  
Utility.log("Thread " + nThreadID + " is over!"); MH~qfH>K  
bDownOver = true; .^+$w $  
//nPos = fileAccessI.write (b,0,nRead); 5<GRi "7A@  
} >~bj7M6t  
catch(Exception e){e.printStackTrace ();} z(#hL-{c  
} ';L^mxh  
} j!8+|eA kk  
RlPByG5K  
"l;8 O2;g  
//打印回应的头信息 YV!V9   
public void logResponseHead(HttpURLConnection con) Q1&dB{L  
{ V$F.`O!hfi  
for(int i=1;;i++) \rnG 1o  
{ '!L1z45  
String header=con.getHeaderFieldKey(i); #3[b|cL  
if(header!=null) umn~hb5O  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %+W >+xRb  
Utility.log(header+" : "+con.getHeaderField(header)); wdDHRW0Y  
else -$|X\#R  
break; =Bqa <Js  
} "^e?E:( 3  
} ]mT} \b  
S7>gNE;%]u  
J#Eh x|  
public void splitterStop() 1E_Ui1[  
{ c89vx 9  
bStop = true; xi^e =:;`  
} ?Pw \&q  
cZT.vA#  
zi[M{bm  
} 2/q=l?  
R2ZQBwB  
^aWNtY' :  
/* '*Mb .s"  
**FileAccess.java AFUl   
*//文件访问(定位,写) MF sy`aiS  
package NetFox; x`l; ;  
import java.io.*; ^TuEp$Z=  
(uc)^lfX  
Ou,_l  
public class FileAccessI implements Serializable{ C}EDl2  
r@UY$z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C2i..iD  
RandomAccessFile oSavedFile; l<%~w U  
long nPos; '+tT$k  
%"fKZ  
3(p6ak2lv  
public FileAccessI() throws IOException %-|q3 ^s  
{ !jnIXvT1qy  
this("",0); x^skoz  
} _\;# a  
+Z]%@"S?  
^ w1R"qE"m  
public FileAccessI(String sName,long nPos) throws IOException 74Wg@! P  
{ V3UGx'@^y  
oSavedFile = new RandomAccessFile(sName,"rw"); l);8y5  
this.nPos = nPos; W/Q%%)J  
oSavedFile.seek(nPos); T bWZw  
} +N_%|!F-c  
dq(L1y870  
^`?> Huu<w  
public synchronized int write(byte[] b,int nStart,int nLen) >f8,YisH  
{ 1`\kXaG  
int n = -1; k@U`?7X  
try{ S`KCVQ>V  
oSavedFile.write(b,nStart,nLen); k<qH<<r*  
n = nLen; $c47cJO)W  
} :h~!#;w_  
catch(IOException e) "r+<=JU>OV  
{ u;}B4Rx  
e.printStackTrace (); J< M;vB)  
} V1;-5L75  
(B#|3o  
oFp&j@`k8j  
return n; $@wkQ%  
} iKY&gnu"  
&r%3)Z8Et  
c*Nbz,:  
} w[-Bsf  
!6C d.fpWL  
k>`X! "  
/* DUr1s]+P  
**SiteInfoBean.java FU3B;Fn^Z(  
*/ ?2;G_P+  
package NetFox; $n"Llw&)  
cpVi9]  
hg @Jpg  
public class SiteInfoBean { (6{ VMQ  
wBET.l'd  
i\G3 u#  
private String sSiteURL; //Site's URL Ui&$/%Z|  
private String sFilePath; //Saved File's Path qQ_QF  
private String sFileName; //Saved File's Name 6wgOmyJx  
private int nSplitter; //Count of Splited Downloading File %*nZ,r  
 2Mda'T8  
kZNZ?A<D  
public SiteInfoBean() n21J7;\/+  
{//nSplitter的缺省值为5 x7?{*w&r  
//default value of nSplitter is 5 x3 S  
this("","","",5); 7@?b _  
} -E7\ .K3  
JSU\Hh!  
Tx(R3B+u7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "K<VZ  
{ F`u~Jx8.*  
sSiteURL= sURL; O}Jb,?p  
sFilePath = sPath; ;l'I. j  
sFileName = sName; >. Y ~F(  
this.nSplitter = nSpiltter; G. }yNjL8  
c z|IBsa*  
U VT8TN-T  
} &%lhov  
xph60T  
fVM%.`  
public String getSSiteURL() _$0Ix6y,  
{ Tx5L   
return sSiteURL; 1;W>ceN"  
} B.?yHaMI[  
c.fj[U|j  
NmQ]qv  
public void setSSiteURL(String value) AZa3!e/1  
{ /2:r}O  
sSiteURL = value; P(`IY +  
} u2t<auE9^  
UTPl7po5D  
X'c5s~9  
public String getSFilePath() &a`-NRU#  
{  VV  
return sFilePath; [Z 0 e$  
} 4v>V7T.  
MPt7 /  
? _W*7<  
public void setSFilePath(String value) ;VuIQ*@m"  
{ JG[+e*8  
sFilePath = value; Y%faf.$/9  
} k=@Q#=;*[W  
f_7p.H6\  
G<-.{Gx)  
public String getSFileName() Bg`b*(Q  
{ 3 *G=U  
return sFileName; EP[ gq  
} rnr7t \a~]  
v% 1#y5  
,'!&Z *  
public void setSFileName(String value) U2aE:$oeYi  
{ G > ,rf ]N  
sFileName = value; C?O{l%0  
} "\9@gfsp)  
&^<94l  
-b{*8(d<I  
public int getNSplitter() gor6c3i  
{ x!< C0N>?z  
return nSplitter; lY1m%  
} ESO(~X+  
Pwq} ;+  
w Bl=]BW!%  
public void setNSplitter(int nCount) rN}^^9  
{ T>c;q%A/  
nSplitter = nCount; g9gyWz  
} <W?,n%  
} L^=>)\R2$[  
>$?Z&7Lv  
+z4NxR   
/* "-hgeQX  
**Utility.java VHJr+BQ1K/  
*/ mz#(\p=T  
package NetFox; sK\?i3<?  
xpV8_Gz;  
H(pOR< `  
public class Utility { %B~`bUHjq  
lu>>~vy6  
Rn}+l[]jC  
public Utility() g~cWBr%>  
{ $/D@=P kc  
mb&b=&  
I*#~@:4*  
} aqMZ%~7  
3Mdg&~85  
//线程睡眠 Yux7kD\c  
public static void sleep(int nSecond) N+r~\[N\9  
{ HloP NE&}  
try{ )N}xKw|  
Thread.sleep(nSecond); P017y&X  
} Me8d o; G|  
catch(Exception e) r}vr E ^Q  
{ ue`F|  
e.printStackTrace (); !0w'S>e  
} [0 W^|=#K  
} 9/nL3U@i1  
KR{kn[2|Q  
//日志 :!3P4?a  
public static void log(String sMsg)  Pg`^EJ+  
{  UWu|w  
System.err.println(sMsg); ^@6eN]  
} +oyc9PoXF  
5Wn6a$^  
p>MX}^6  
public static void log(int sMsg) M]6=Rxq1:E  
{ 87*R#((  
System.err.println(sMsg); au GN~"n^  
} @ #V31im"N  
} yX8F^iv[  
6/GhQ/T%D  
Sm-nb*ZyC  
/* jL 2f74?1  
**TestMethod.java eqLETo@} *  
*/ M14pg0Q  
package NetFox; zis-}K<   
Vv zd>yII  
 s cn!,  
public class TestMethod { 3Hq0\Y"Y  
{8t;nsdm!  
~)()PO  
public TestMethod() ^P]: etld9  
{ ///xx/weblogic60b2_win.exe h>\}-|Ek  
try{ z muq4-.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J,E&Uz95%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); PUa~Apj '  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0}aJCJ9sx=  
fileFetch.start(); %,>,J`  
} ?lbX.+  
catch(Exception e){e.printStackTrace ();} u_mm*o~)g  
~r!jVK>^  
dkCSqNFL)  
} >0512_J+  
tl#hCy  
"b2Mk-qP  
public static void main(String[] args)  gs9f2t  
{ !N!M NsyDz  
new TestMethod(); <nIU]}q  
} H4%wq  
} );=JoRQ{  
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