http断点续传简单实现（java)

/* }dHiW:J>  
**SiteFileFetch.java wMUnZHd{|  
*/ C\; 8l}t  
package NetFox;
"_K 6=  
import java.io.*; /iN\)y#u1  
import java.net.*; h|H;ZC(B  
GMNb;D(>K  
E\zhxiI  
public class SiteFileFetch extends Thread { b910Z?B^L  
bpx=&74,6m  
KCT8Q!\  
SiteInfoBean siteInfoBean = null; //文件信息Bean G;m"ao"2  
long[] nStartPos; //开始位置 ul%bo%&~  
long[] nEndPos; //结束位置 l xfdJNb  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #TW
c` 8  
long nFileLength; //文件长度 nGbrWu]w  
boolean bFirst = true; //是否第一次取文件 sy?>e*-{  
boolean bStop = false; //停止标志 !kcg#+s91  
File tmpFile; //文件下载的临时信息 .'a|St  
DataOutputStream output; //输出到文件的输出流 FSmi.7  
@Y,F&8a$  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） uqUo4z5T  
public SiteFileFetch(SiteInfoBean bean) throws IOException Z:v1?v  
{ _UBI,Dg]  
siteInfoBean = bean; '=H^m D+gl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _tk5?9Ykn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); vck$@3*  
if(tmpFile.exists ()) ) G{v>Z,  
{ +i^s\c!3;  
bFirst = false; f3N:MH-c  
read_nPos(); 8Vn6* Xn  
} }$)<k
 
else *Vl =PNn-  
{ jvV8`BQ{  
nStartPos = new long[bean.getNSplitter()]; c7F&~RLC  
nEndPos = new long[bean.getNSplitter()]; ie(7m|.  
} (<l2 ^H  
v'!N

t
k  
3+-(;>>\  
Q]wM/7  
} wuzz%9;@B  
XNUqZ-M:  
RFJ;hh  
public void run() FZ9<Q  
{ ^kr)U8  
//获得文件长度 W/>?1+r.Z  
//分割文件 iy]}1((hR  
//实例FileSplitterFetch $3TTHS o  
//启动FileSplitterFetch线程 !I[n|r"  
//等待子线程返回 7fay:_  
try{ $vBU}~l7  
if(bFirst) JF*g!sV%  
{ >, E$bm2  
nFileLength = getFileSize();  9+QrTO  
if(nFileLength == -1) 5E!m! nBZ  
{ hU 7fZl%yl  
System.err.println("File Length is not known!"); ]M(mq`K  
} sZ"U=6R  
else if(nFileLength == -2) [kOA+\v  
{ x+cF1N2.  
System.err.println("File is not access!"); ~vGtNMQg  
} `z_7[$\~  
else &HK
s >  
{ !C#RW=h9  
for(int i=0;i<nStartPos.length;i++) rcZ SC3  
{ eeU$uR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @MB _gt)7?  
} _vdxxhJ=P3  
for(int i=0;i<nEndPos.length-1;i++) ik*)j  
{ n^\;*1%$c@  
nEndPos = nStartPos[i+1]; Qcy`O m^2  
} 38rZ`O*D  
nEndPos[nEndPos.length-1] = nFileLength; 5|CiwQg|,p  
} 3\n{,Q  
} #( sNk,^Ax  
=&pN8PEn\  
&fW=5'  
//启动子线程 yCIgxPv|7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <j\;>3Q  
for(int i=0;i<nStartPos.length;i++) i
g}e@]  
{ A+*oT(`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E`fssd~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), r0deBRM  
nStartPos,nEndPos,i); aT!9W'uY  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?=!XhU .  
fileSplitterFetch.start(); .w_`d'}  
} RQCQGa^cP  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Kk>qgi$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5\0.[W
{^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _IV@
^v  
nEndPos = " + nFileLength); )v=G}j^  
// fileSplitterFetch[nPos.length-1].start(); cXcx_-  
(VaN\+I:T  
*ZR@z80i  
//等待子线程结束 AaYrVf 9!  
//int count = 0; YC&jKx.>  
//是否结束while循环 g0j4<\F2\  
boolean breakWhile = false; 
loUwRz  
` G=L07  
KWJgW{{v  
while(!bStop) :6$4K"^1  
{ bmVgTm&  
write_nPos(); W)!{U(X  
Utility.sleep(500); 2nU NI U  
breakWhile = true; iW@Vw{|i I  
1m`tqlFU9  
7~ese+\smG  
for(int i=0;i<nStartPos.length;i++) o,Zng4NY  
{ i!W8Q$V  
if(!fileSplitterFetch.bDownOver) S@xsAib0J  
{ pLQSG}N  
breakWhile = false; )L<?g!j~  
break; o9LD6$  
} 1O2h9I$bk  
} %DRy&k/T  
if(breakWhile) 2^bpH%  
break; pR6A#DgB  
'}+X,Usm  
^wF@6e7/&  
//count++; Q^Z<RA(C  
//if(count>4) ?>.g;3E$  
// siteStop(); 9LEilmPs  
} KTK6#[8A  
|5IY`;+9  
)~.&bEm\  
System.err.println("文件下载结束！"); sIRrEea  
} UW/3{2  
catch(Exception e){e.printStackTrace ();} ]X: rby$  
} ZC5Yve8  
|/\U^AHm"h  
ju^"vw  
//获得文件长度 }C{}oLz  
public long getFileSize() 2b4pOM7W  
{ \ ~LU 'j  
int nFileLength = -1; Iwt2}E(e  
try{ IN|i)?rh  
URL url = new URL(siteInfoBean.getSSiteURL()); ,-7/]h,l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OHP3T(Q5  
httpConnection.setRequestProperty("User-Agent","NetFox"); {|5$1v  
?]\W8)  
0"kE^=  
int responseCode=httpConnection.getResponseCode(); QK?2E  
if(responseCode>=400) R)d99j^"  
{ )qyx|D  
processErrorCode(responseCode); ~f=6?5.wa  
return -2; //-2 represent access is error dx13vZ3[U  
} XW~ BEa  
tT* W5  
YZBzv2'\x  
String sHeader; n.a=K2H:V  
nrS[7~  
LN.Bd,  
for(int i=1;;i++) *K}z@a_  
{ cPx~|,)l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \L9?69B~  
//Utility.log(in.readLine()); V8nz-DL{  
sHeader=httpConnection.getHeaderFieldKey(i); g^z5fFLg/8  
if(sHeader!=null) Tw}?(\ya  
{ D0#T-B\#  
if(sHeader.equals("Content-Length")) @7Rt4}g  
{ vzyNc'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); urT/+deR  
break; oBRm\8 2|  
} 8tV=fSHd  
} v#:+n+y\z  
else w%8ooQ|C  
break; Krp <bK6  
} Zr.\`mG4f  
} vNC$f(cQ  
catch(IOException e){e.printStackTrace ();} h{W$ fZc<  
catch(Exception e){e.printStackTrace ();} Y|m_qB^_  
qD(fYOX{C  
bIb6yVnHi  
Utility.log(nFileLength); u+mjguIv  
Q$?7)yyu+  
*#Lsjk~_-  
return nFileLength; G>=9gSLM  
} s<Ex"+  
ReI=4Jq11  
N?a1sdR  
//保存下载信息（文件指针位置） P&[Ft)`  
private void write_nPos() :jk)(=^  
{ mh A~eJ  
try{ 'ZGT`'ri  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hF{x')(#l  
output.writeInt(nStartPos.length); jU]]:S4xD/  
for(int i=0;i<nStartPos.length;i++) `P^u:  
{ {k_ PMl0G  
// output.writeLong(nPos); o%V @D'w  
output.writeLong(fileSplitterFetch.nStartPos); [!J @a  
output.writeLong(fileSplitterFetch.nEndPos); Q? <-`7  
}
?qf:_G  
output.close(); =E [4H  
} $@[dm)M  
catch(IOException e){e.printStackTrace ();} 3{NaZIk  
catch(Exception e){e.printStackTrace ();} DA+A >5/  
} ZL4l (&"  
n0+g]|a AF  
g[#k.CuP  
//读取保存的下载信息（文件指针位置） 'DCKD4@C/  
private void read_nPos() }b_R5U$@@  
{ c!\.[2n  
try{ jw/'*e  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <=;H[} e  
int nCount = input.readInt(); ,]~u:Y}  
nStartPos = new long[nCount]; bGZhUEq  
nEndPos = new long[nCount]; C1X}3bB  
for(int i=0;i<nStartPos.length;i++) d9
8))G~W  
{ &Pu+(~'Q  
nStartPos = input.readLong(); b$dJ?%W  
nEndPos = input.readLong(); g(-;_j!=  
} o,?!"*EP  
input.close(); =7 Jy  
} pT("2:)x  
catch(IOException e){e.printStackTrace ();} V*6l6-y~Ih  
catch(Exception e){e.printStackTrace ();} v2/yw,  
} gHQPhe#n  
TqS2!/jp  
&
u+yM D  
private void processErrorCode(int nErrorCode) u:_sTfKm&  
{ [NHg&R H  
System.err.println("Error Code : " + nErrorCode); RDUT3H6~  
} e1^fUOS  
8g<Q5(  
?!bd!:(N  
//停止文件下载 vC)"*wYB{  
public void siteStop() X}zX`]:I'  
{ nGq]$h  
bStop = true; Ef
2Yl  
for(int i=0;i<nStartPos.length;i++) y]yine  
fileSplitterFetch.splitterStop(); jMN)?6$=  
u|(Ux~O  
4^0d)+Ff  
} Sp 7u_Pq{  
} c:=7lI  
//负责部分文件的抓取 `%$8cZ-kr  
**FileSplitterFetch.java _REqT  
*/ `+roQX.p  
package NetFox; C1h#x'k  
y\^@p=e  
O{PW  
import java.io.*; #$LH2?)  
import java.net.*; rlR !&  
seu ~'s-  
}sf YCz  
public class FileSplitterFetch extends Thread { Z8&4z.6_  
WHp97S'd  
TNh=4xQ}  
String sURL; //File URL ^ Xm/  
long nStartPos; //File Snippet Start Position X.s*>'  
long nEndPos; //File Snippet End Position yt. f!"  
int nThreadID; //Thread's ID 9GO}&7   
boolean bDownOver = false; //Downing is over
'#O;mBPNi  
boolean bStop = false; //Stop identical 3Bejp+xX  
FileAccessI fileAccessI = null; //File Access interface A/!<kp{S  
 ci`zR9Ks  
~ct2`M$TL(  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException py]KTRzy  
{ lwVk(l Z  
this.sURL = sURL; i*X{^A73"  
this.nStartPos = nStart; Y^QKp"  
this.nEndPos = nEnd; ]53O}sH>  
nThreadID = id; F7\BF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Takt_N  
} gXLCRn!iR  
@zo7.'7P  
G;/Q>V  
public void run() 34z_+  
{ "\7v  
while(nStartPos < nEndPos && !bStop) G@9u:\[l  
{ IrJ+Jov  
gdl| ^*tc  
>L8?=>>?\  
try{ 0|ZVA+  
URL url = new URL(sURL); {{32jU7<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); uM<|@`&b  
httpConnection.setRequestProperty("User-Agent","NetFox"); O#vn)+Y,*  
String sProperty = "bytes="+nStartPos+"-"; q%>7L<r  
httpConnection.setRequestProperty("RANGE",sProperty); Gu5~DyT`G  
Utility.log(sProperty); GMz8B-vk  
PkTfJQP8  
[cDbaq,T  
InputStream input = httpConnection.getInputStream(); b\:~;  
//logResponseHead(httpConnection); H#35@HF*o  
3 -tO;GKb  
:V-k'hm &  
byte[] b = new byte[1024]; {-HDkG' 8  
int nRead; 0E-pA3M6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) kQLT$8io  
{ [9OSpq  
nStartPos += fileAccessI.write(b,0,nRead); Dzr e'  
//if(nThreadID == 1) fuMN"T 6%+  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UgR:qjI  
} _5b0wdB  
6a*83G,k  
RwW$O@0  
Utility.log("Thread " + nThreadID + " is over!"); J@QdieW6  
bDownOver = true; vs+QbI6>-  
//nPos = fileAccessI.write (b,0,nRead); wZjlHe  
} fp{G|.SA  
catch(Exception e){e.printStackTrace ();} }S*/b1  
} c_#*mA"+  
} +oZH?N4yaM  
b0 &  
l xe`u}[  
//打印回应的头信息 3htq[Ren  
public void logResponseHead(HttpURLConnection con) it)ZP H  
{ \]8VwsP  
for(int i=1;;i++) }~F~hf>s  
{ ^LVk5l)\>g  
String header=con.getHeaderFieldKey(i); Umz05*  
if(header!=null) y@3Q;~l,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ePEe?o4;  
Utility.log(header+" : "+con.getHeaderField(header)); :m Kxa  
else Me,<\rQ  
break; !MoOKW  
} Yl~$V(  
} "]#'QuR  
ul@3 Bt  
I^G^J M!  
public void splitterStop() h=6xZuA\  
{ F+ukAT  
bStop = true; Q_]~0PoH  
} Ux}W&K/?'  
|gv{z"  
Efx=T$%^&  
} 90fs:.  
>F[GVmC  
KQ{
Lt?S  
/* < bFy(+  
**FileAccess.java O9^T3~x[V  
*//文件访问(定位，写) "Zcu[2,  
package NetFox; 1`JB)9P  
import java.io.*; 3+(z_!Qh  
?YBaO,G9o  
qSTWb%  
public class FileAccessI implements Serializable{ rslvsS:  
jXp. qK\"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 c<4F4k7  
RandomAccessFile oSavedFile;  ?Vc0)  
long nPos; VI_+v[Hk/  
CxDcY  
a9l8{3  
public FileAccessI() throws IOException 8z}^j
TM  
{ AbfZ++aJ  
this("",0); NYB "jKMk  
} . I==-|  
Vb!O8xV4;+  
c-B/~&  
public FileAccessI(String sName,long nPos) throws IOException R0wf#%97  
{ aQUGNa0+d  
oSavedFile = new RandomAccessFile(sName,"rw"); pOA!#Aj)  
this.nPos = nPos; BpH%STEN  
oSavedFile.seek(nPos); VEs5;]#<2D  
} G\=_e8(  
Kkv<"^H  
fF;h V  
public synchronized int write(byte[] b,int nStart,int nLen) >zngJ$  
{ c}-(.eu  
int n = -1; P!e=b-T  
try{ m Ni2b*k  
oSavedFile.write(b,nStart,nLen); 2*2:-ocl$  
n = nLen; z%sy$^v@vD  
} I[D8""U  
catch(IOException e) M0w/wt|  
{ {C")#m-0  
e.printStackTrace (); rN5tI.iC  
} q3h'l,  
4 1t
)(+r  
;>>C)c4V"  
return n; 9v?l  
} "9XfQ"P  
Ew$I\j*  
mgQIhXH5L  
} vzXag*0  
YGk9b+`  
%8r/oS  
/* hXB|g[zT  
**SiteInfoBean.java .L EY=j!-s  
*/ 6F|j(LB  
package NetFox; ~OypE4./1  
h<x4YB5Mj  
lV6dm=k  
public class SiteInfoBean { {mTytT  
;Ii1B{W  
_#C()Ro*P  
private String sSiteURL; //Site's URL 314=1JbL  
private String sFilePath; //Saved File's Path KzO,*M  
private String sFileName; //Saved File's Name j0mM>X HB  
private int nSplitter; //Count of Splited Downloading File p|[B =.c{  
WZn.;  
<1"+,}'x  
public SiteInfoBean() )L5i&UK.  
{//nSplitter的缺省值为5 X.FGBR7=q  
//default value of nSplitter is 5 w>e s  
this("","","",5); igC_)C^i>  
} c#cx>wq9  
$`J_:H%  
X}A'Cg0y  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xDLG=A%]z  
{ /+|#^:@  
sSiteURL= sURL; =L]Q2V}  
sFilePath = sPath; !{%&=tIZ  
sFileName = sName; !3qVB  
this.nSplitter = nSpiltter;
=#xK=pRy;  
e0HfP v_  
F0lOlS   
} F]+~x/!  
j/!H$0PN  
q(IQa@$SR  
public String getSSiteURL() H/fUM  
{ ]$b2a&r9  
return sSiteURL; *rh,"Zo  
} s:>\/[*>0c  
L.'}e{ldW  
h2Bz F  
public void setSSiteURL(String value) fV\]L4%  
{ DN] v_u+}  
sSiteURL = value; )>a B  
} 5&!c7$K0  
{XCf-{a]~  
9KuD(EJS  
public String getSFilePath() quxdG>8  
{ * ?Jz2[B  
return sFilePath; r@G#[.*A>  
} WyhhCR=;  
PBjmGwg7  
s^8u&y)3  
public void setSFilePath(String value) s Be7"^  
{ !|Q5Zi;aX7  
sFilePath = value; >QkP7Kb  
} 8V/L:h#7  
~+6Vdxm  
*%5{'  
public String getSFileName() 2f~($}+*  
{ %;xOB^H^  
return sFileName; w3T]H_V  
} p{$p $/A  
F>hZ{  
0Q5^C!K  
public void setSFileName(String value) U9hS<}<Ki  
{ OQ
&'Dti  
sFileName = value; RP4Ku9hk  
} ~ 5"JzT  
{FO$yw=>  
dt\jGD  
public int getNSplitter() G4
_,  
{ ?Bi*1V<R  
return nSplitter; z(y*hazK  
} gb|Q%LS9R  
Xd `vDgD  
WYcA8X/  
public void setNSplitter(int nCount) 5e8AmY8;  
{ }2
8=  
nSplitter = nCount; ,E )|y4  
} 0MF}^"R  
} c]k*}W3T  
_QOZsEe  
$.%rAa_H  
/* Fg]?zEa  
**Utility.java sBX-X$*N  
*/ ^Q<mV*~  
package NetFox; Wi.5Y{  
t<iEj"5  
6A R2htN^  
public class Utility { I^\&y(LJF  
*XOJnyC_H  
&EGqgNl  
public Utility() q'[}9e`Q  
{ 7r#ymQ  
k44Q):ncY7  
5*%#o  
} "UFs~S|e  
0pb'\lA  
//线程睡眠 OPJ: XbG  
public static void sleep(int nSecond) Y$K!7Kq  
{ Cizvw'XDV  
try{ igL<g  
Thread.sleep(nSecond); E>LkJ
Sy=  
} {V19Zv"j  
catch(Exception e) uP $Cj  
{ zw<p74DH  
e.printStackTrace (); . 5y"38e  
} ZzGahtx)Y  
} ym,H@~  
iRo.RU8>  
//日志 ;h=*!7:  
public static void log(String sMsg) k*rZ*sSp  
{ {PU!=IkTS  
System.err.println(sMsg); 'wasZ b<^  
} UB`ToE|Ii  
m><w0k?t  
N7r_77%m0  
public static void log(int sMsg) `$LWmm#  
{ 6DIZ@oi  
System.err.println(sMsg); g6t"mkMY L  
} /&#XhrT  
} lA(Q@yEW  
/'2O.d0}.  
) /vhclkb  
/* 8F(h*e_?  
**TestMethod.java C;+(Zp  
*/ uP3_FX: e  
package NetFox; ^)!F9h+  
\`<cH#  
.{KjEg 6  
public class TestMethod { `?g`bN`Vn  
bu7'oB~:V^  
2aZw[7s  
public TestMethod() %_-zWVJ  
{ ///xx/weblogic60b2_win.exe 9h90huyKF  
try{ #m{{a]zm^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); n]_[NR) i  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); UV 4>N  
SiteFileFetch fileFetch = new SiteFileFetch(bean); RgdysyB  
fileFetch.start(); YpAg  
} |'ln?D:&  
catch(Exception e){e.printStackTrace ();} -~[9U,  
/^
{BUo  
7\zZpPDV  
} c\6+=\  
bi y4d  
F;ZSzWq  
public static void main(String[] args) #ge)2  
{ \@3Qi8u//  
new TestMethod(); 9Y
a<My  
} 1 2++RkL#  
} up
3O|lj4  
点击下载更多相关资料