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http断点续传简单实现(java)

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/* i2FD1*=/?  
**SiteFileFetch.java EAD0<I<>  
*/ y  KYP  
package NetFox; iIGI=EwZ  
import java.io.*; A`x -L  
import java.net.*; W`Q$t56  
b$goF }b'g  
};"+ O  
public class SiteFileFetch extends Thread { QlRoe| {  
X<Th{kM2  
T}t E/  
SiteInfoBean siteInfoBean = null; //文件信息Bean {7=WU4$  
long[] nStartPos; //开始位置 'ybth  
long[] nEndPos; //结束位置 $W/+nmb)@K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1qLl^DW  
long nFileLength; //文件长度 ~3'RW0  
boolean bFirst = true; //是否第一次取文件 z#{ 0;t  
boolean bStop = false; //停止标志 $h 08Z  
File tmpFile; //文件下载的临时信息 Gin_E&%g  
DataOutputStream output; //输出到文件的输出流 pF sCd"zv  
f8LrDR  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) .|-l+   
public SiteFileFetch(SiteInfoBean bean) throws IOException hg?j)jl|  
{ <}EV*`w4  
siteInfoBean = bean; B?;' lDz*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *gd?>P7\0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <Qcex3  
if(tmpFile.exists ()) )+n,5W  
{ QY~<~<d+G  
bFirst = false; U/X|i /  
read_nPos(); ~_ u*\]-  
} 15xd~V?ai:  
else g5tjj.  
{ Qe>i{:N  
nStartPos = new long[bean.getNSplitter()]; G`]v_`>  
nEndPos = new long[bean.getNSplitter()]; x)ddRq l  
} af<NMgT2s~  
IpWy)B>Fl3  
MX!u$ei  
:!JpP R5  
} _{LN{iqDv  
yn/?= ?0  
4<G?  
public void run() 7Wwp )D  
{ ~A`&/U  
//获得文件长度 (C`FicY  
//分割文件 O{k89{  
//实例FileSplitterFetch [=F>#8=  
//启动FileSplitterFetch线程 gppBFS  
//等待子线程返回 bp]^EVx  
try{ Hp)X^O"  
if(bFirst) n7IL7?!o  
{ `z|= ~  
nFileLength = getFileSize(); CM%|pB/z  
if(nFileLength == -1) r}/yi  
{ V$/u  
System.err.println("File Length is not known!"); Em e'Gk  
} #XTY7,@ P  
else if(nFileLength == -2) [3O^0-:6E  
{ lx\qp`w  
System.err.println("File is not access!"); 0U82f1ei  
} :+~KPn>w5  
else _PXG AS  
{ tcBC!_vF  
for(int i=0;i<nStartPos.length;i++) =n@F$/h  
{ aO8c h  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); D JLiZS  
} vkd[: CC  
for(int i=0;i<nEndPos.length-1;i++) B4]AFRI  
{ m#oh?@0}  
nEndPos = nStartPos[i+1]; )W&o?VRfO  
} xGYSi5}z  
nEndPos[nEndPos.length-1] = nFileLength; EY+/.=$x  
} _W)`cr  
} 4$yV%[j  
-1qZqU$h  
qqnclqkw&  
//启动子线程 hi!L\yi  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; m7$8k@r  
for(int i=0;i<nStartPos.length;i++) A2m_q>> !  
{ P^ptsZ%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wL4Z W8_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2R^O,Vu*W  
nStartPos,nEndPos,i); `J72+RA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wgCvD  
fileSplitterFetch.start(); w3^NL(>  
} CF]i}xpWV  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =%!e(N'p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ePf+[pV3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S8 :"<B)  
nEndPos = " + nFileLength); &J8 Z@^  
// fileSplitterFetch[nPos.length-1].start(); hf;S]8|F  
V,V*30K5  
6}ce1|mkg/  
//等待子线程结束 41u*w2j  
//int count = 0; 1hl]W+9  
//是否结束while循环 <0CzB"Ap  
boolean breakWhile = false; #EJhAJ  
fJaubDxa  
J.#(gFBBl\  
while(!bStop) e# t3u_  
{ ,eR8 ~(`=  
write_nPos(); 6SE6AL<b  
Utility.sleep(500); $:Rn;  
breakWhile = true; /\ytr%7,'  
&~RR&MdZ2  
=WC-Sj{I  
for(int i=0;i<nStartPos.length;i++) !RS9%ES_?  
{ (=1)y'.  
if(!fileSplitterFetch.bDownOver) U4Z[!s$  
{ ,Du@2w3Cq  
breakWhile = false; N;uUx#z  
break; Ab/j(xr=  
} W+_RhJ  
} p8Iw!HE  
if(breakWhile) 7_-w_"X  
break;  3P1&;  
~ |6dH  
P` #QGZ>  
//count++; [r(Qs|  
//if(count>4) ;x-(kIiE  
// siteStop(); #?dUv#  
} f\fdg].!  
|'tW=  
d{f@K71*  
System.err.println("文件下载结束!"); b/t  
} P.djd$#  
catch(Exception e){e.printStackTrace ();} 6R`Oh uN.>  
} Y2C9(Zk U  
b.s9p7:J  
%JtbRs(~q  
//获得文件长度 mLwoi!]m  
public long getFileSize() Ow3P-UzU3  
{ p,F^0OU2}:  
int nFileLength = -1; <\" .L  
try{ (zG.aaz*C  
URL url = new URL(siteInfoBean.getSSiteURL()); SVagT'BB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H6gU?9%  
httpConnection.setRequestProperty("User-Agent","NetFox"); ' _dzcN,z  
~]BMrgn  
ZsZcQj6G,  
int responseCode=httpConnection.getResponseCode(); YzAFC11,  
if(responseCode>=400) Po(]rQbE  
{ 9GgA6#  
processErrorCode(responseCode); NBjeH tT  
return -2; //-2 represent access is error @b2`R3}9R  
} z% 1{  
9I`Y-D  
C9qJP^F  
String sHeader; 3NIUW!gr  
|ETiLR=&  
][d,l\gu+s  
for(int i=1;;i++) 'xnnLCm.  
{ X<]qU3k5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); HRB[GP+  
//Utility.log(in.readLine()); fTq C:r|st  
sHeader=httpConnection.getHeaderFieldKey(i); *f5l=lDOB  
if(sHeader!=null) EVt? C+  
{ ?7[alV~  
if(sHeader.equals("Content-Length")) '9s5OTkN ;  
{ 1tB[_$s  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); BByCM Y  
break; a{SBCy  
} B&Y_2)v  
} Ue*C>F   
else #eK=  
break; fQ 7vL~E  
} w8iR|TV  
} @*MC/fe  
catch(IOException e){e.printStackTrace ();} C5W>W4EM  
catch(Exception e){e.printStackTrace ();} b.F^vv"]]  
Vw#{C>  
:!fG; )=  
Utility.log(nFileLength); WKmbNvN^  
W0XF~  
Xf d*D  
return nFileLength; 9!U@"~yB  
} -?6MU~"GK  
GX&b;N  
p'n4)I2#  
//保存下载信息(文件指针位置) 4v'A\~ZU  
private void write_nPos() la <npX  
{ ceT&Y{T  
try{ ^j)BKD-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); K93p"nHN  
output.writeInt(nStartPos.length); EE=3  
for(int i=0;i<nStartPos.length;i++) ZH,4oF  
{ w$|l{VI  
// output.writeLong(nPos); dQb.BOI)h  
output.writeLong(fileSplitterFetch.nStartPos); N ]N4^A'  
output.writeLong(fileSplitterFetch.nEndPos); !k&Q 5s:  
} @}s$]i$|-  
output.close(); 7v7G[n  
} _:`!DIz~9}  
catch(IOException e){e.printStackTrace ();} CO?Xt+1hR  
catch(Exception e){e.printStackTrace ();} nZy X_J,Vd  
} sC"}8+[)S3  
 {@Y  
CHJ> {b`O  
//读取保存的下载信息(文件指针位置) _qXa=|}V.  
private void read_nPos() xJs;v  
{ ($nrqAv4  
try{ ~8T(>!hE1h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !yOeW0/2[  
int nCount = input.readInt(); SC &~s$P;  
nStartPos = new long[nCount]; C\ZkGX  
nEndPos = new long[nCount]; !? 5U|  
for(int i=0;i<nStartPos.length;i++) sZ&G%o  
{ "xRBE\B  
nStartPos = input.readLong(); oslJC$cy'  
nEndPos = input.readLong(); <?Wti_ /M  
} q2rUbU_A(  
input.close(); $2~\eG=u H  
} vhuw &.\  
catch(IOException e){e.printStackTrace ();} <plC_{Y:wu  
catch(Exception e){e.printStackTrace ();} D]s]"QQ8  
} M$Zo.Bl$(  
,)!u)wz  
TXXy\$  
private void processErrorCode(int nErrorCode) p&-'|'![l  
{ ;Xvp6.:  
System.err.println("Error Code : " + nErrorCode); _c$9eAe  
}  '1^B +m  
3jH\yXj  
k n[Y   
//停止文件下载 ;a{:%t  
public void siteStop() WY:&ugGx  
{ llV3ka^!  
bStop = true; &sXRN &Fp  
for(int i=0;i<nStartPos.length;i++) <#GB[kQa  
fileSplitterFetch.splitterStop(); gb=/#G0R  
6[E|  
F0vM0 e-  
} '_k+WH&  
} :!a 2]-D}  
//负责部分文件的抓取 YW@#91.  
**FileSplitterFetch.java hwN?/5  
*/ 9[c%J*r   
package NetFox; 6r: ?;j~l  
vIl+#9L0  
so$(_W3E,  
import java.io.*; 1?*  
import java.net.*; 0 [?ny`Y  
;Vik5)D2D  
*=V7@o  
public class FileSplitterFetch extends Thread { D?yG+%&9  
|t iUej  
%1 vsN-O}8  
String sURL; //File URL C;QAT  
long nStartPos; //File Snippet Start Position Vm}%ttTC  
long nEndPos; //File Snippet End Position #rO8Kf  
int nThreadID; //Thread's ID oh"O07  
boolean bDownOver = false; //Downing is over 65h @}9,U  
boolean bStop = false; //Stop identical {U<xdG  
FileAccessI fileAccessI = null; //File Access interface l!}:|N Yh!  
-<v~snq'  
`@[c8j7  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vx_o(wof  
{ +YLejjQ  
this.sURL = sURL; iy.2A!f^.  
this.nStartPos = nStart; ,lA.C%4au~  
this.nEndPos = nEnd; $N :Vo(*  
nThreadID = id; N,2s?Y_!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 V7G7&'  
} {!|}=45Z  
DrnJ;Hi"  
;,i]w"*  
public void run() i wxVl)QL  
{ )[mwP.T=  
while(nStartPos < nEndPos && !bStop) ay "'#[  
{ \I"Z2N>^z  
R8rfM?"W  
\0lnxLA  
try{ Ev7J+TmXM  
URL url = new URL(sURL); mWR4|1(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o9xlu.QL{c  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2aJS{[  
String sProperty = "bytes="+nStartPos+"-"; Le<w R  
httpConnection.setRequestProperty("RANGE",sProperty); :1t~[-h^  
Utility.log(sProperty); O=SkAsim  
ZxV"(\$n  
/kt2c[9  
InputStream input = httpConnection.getInputStream(); lrf v+  
//logResponseHead(httpConnection); X#3et'  
!RyO\>:q  
\#o2\!@`  
byte[] b = new byte[1024]; K=!Bh*  
int nRead; fwK}/0%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (b'B%rFO  
{ V $z} K  
nStartPos += fileAccessI.write(b,0,nRead); =@k%&* Y?  
//if(nThreadID == 1) mUS_(0q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OHiQ7#y  
} w =. Fj  
8-y{a.,u.  
x(<(t: ?o  
Utility.log("Thread " + nThreadID + " is over!"); ^rvx!?zO  
bDownOver = true; O6IB. >T  
//nPos = fileAccessI.write (b,0,nRead); vSi_t K4  
} WTImRXK4  
catch(Exception e){e.printStackTrace ();} K'K2X-E  
} TuW%zF/  
} rx (2yf  
~QvqG{bFB  
"\0v,!@  
//打印回应的头信息 6JKqn~0Kk  
public void logResponseHead(HttpURLConnection con) PJcwH6m  
{ G$ _yy:  
for(int i=1;;i++) Y&/]O$<  
{ DJgTA]$&  
String header=con.getHeaderFieldKey(i); <SI}lQ'i  
if(header!=null) U|g:`v7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4 C}bJzZ  
Utility.log(header+" : "+con.getHeaderField(header)); +}f9   
else &\apwD  
break; F(t=!k,4\  
} ?c0xRO%y  
} _`64gS}^  
JK.ZdY%  
3;% 5Yu  
public void splitterStop() ^ bEc6`eE  
{ Q WMdn  
bStop = true; \GHiLs,!  
} =gcM%=*'  
lFTF ,G  
o] mD"3_  
} 2h[85\4  
x3PD1JUf  
YZ%Hu)  
/* P-ri=E}>  
**FileAccess.java TDd{.8qf  
*//文件访问(定位,写) 6oF7:lt  
package NetFox; s}N#n(  
import java.io.*; * S=\l@EW  
Ur*6Gi6  
e9Nk3Sj]  
public class FileAccessI implements Serializable{ l x,"EOP  
fu90]upz~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^h{)Gf,+\  
RandomAccessFile oSavedFile; ;|UF)QGa2  
long nPos; bQ~j=\[r  
sg+uBCGB  
ss5 m/i7  
public FileAccessI() throws IOException da (km+  
{ @:KJYm[  
this("",0); C -iK$/U  
} yRo- EP  
:O(^w}sle  
jg?x&'u\)  
public FileAccessI(String sName,long nPos) throws IOException {J^lX/D  
{ d6W SL;$  
oSavedFile = new RandomAccessFile(sName,"rw"); c+2FC@q{l  
this.nPos = nPos; b$Vz2Fzx  
oSavedFile.seek(nPos); /% N r?V  
} EY \H=@A  
JGuN:c$  
%'[&U#-  
public synchronized int write(byte[] b,int nStart,int nLen) 1 5A*7|  
{ _1U1(^)  
int n = -1; 8=]Tr3   
try{ Uh][@35 p  
oSavedFile.write(b,nStart,nLen); n_'s=]~  
n = nLen; ;pnD0bH  
} ij?  
catch(IOException e) IEU^#=n  
{ C:Hoq(  
e.printStackTrace (); Zfyo-Wk  
} qG<$Ajiin  
&gjF4~W]  
qbv#I;  
return n; < P`u}  
} 4Z/f@ZD  
F{UP;"8'  
e @IA20  
} d 9q(xZ5  
:H c0b=  
5|1 T}Z#;  
/* /tUy3myJ  
**SiteInfoBean.java i\dc>C ;  
*/ 3\Xbmq8}  
package NetFox; 0Q^Ikiv   
CxfRV L`7  
hXA6D)   
public class SiteInfoBean { ]8T!qS(UJd  
sVl-N&/  
VZ\B<i  
private String sSiteURL; //Site's URL A,`8#-AX  
private String sFilePath; //Saved File's Path VqS#waNrx  
private String sFileName; //Saved File's Name kcQ'$<Mz<  
private int nSplitter; //Count of Splited Downloading File FXs*vg`  
%?m$`9yU  
HQB(*  
public SiteInfoBean() 8H_l:Z[:i  
{//nSplitter的缺省值为5 D_x +:1(  
//default value of nSplitter is 5 4T=u`3pD7l  
this("","","",5); 6,9o>zT%H  
} ~j<+k4I~  
3"P }n  
E <c9#I=  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) HcqfB NM  
{ lIProF0  
sSiteURL= sURL; Jej` ;I  
sFilePath = sPath; _vZ"4L+Iw+  
sFileName = sName; LA`*_|}qcR  
this.nSplitter = nSpiltter; ak;*W  
A]DTUdL  
mVR P~:+  
} *guoWPA|Ij  
NM06QzE  
ZfB " E  
public String getSSiteURL() YJo["Q  
{ E>}4$q[r  
return sSiteURL; t1%_DPD%W  
} qs QNjt  
,%)6jYHRw  
T,VY.ep/  
public void setSSiteURL(String value) )LyojwY_g  
{ 'Tc]KXD6  
sSiteURL = value; ~t~-A,1  
} oIefw:FE,a  
WH= EPOR,  
u&n' ITH  
public String getSFilePath() TsGE cxIg  
{ }6@pJ G  
return sFilePath; $k2*[sn,  
} tuhA 9}E  
Q*b]_0Rb  
w.0qp)}  
public void setSFilePath(String value) <^lRUw  
{ -k"^o!p  
sFilePath = value; ;W^o@*i{>  
} #cCL.p"]  
u5Ftu?t  
>2Kh0rIH  
public String getSFileName() VL*ovD%-  
{ Et/&^&=\-  
return sFileName; !Uq^7Mw  
} smry2*g  
TEaJG9RU>v  
uNHF'?X  
public void setSFileName(String value) +*hm-lv?  
{ :Cp'm'omb  
sFileName = value; /=gOa\k|p  
} 2^l[(N  
G^` 1]?  
-]t,E,(!  
public int getNSplitter() ]~E0gsq  
{ %y%j*B!%  
return nSplitter; Sx8OhUyux  
} {1b Zg  
nTz6LVF  
rhb@FE)Mc  
public void setNSplitter(int nCount) $9ky{T?YG  
{ Y2?.}ZO  
nSplitter = nCount; 9s_,crq5  
} #jxe%2'Ot  
} q2et|QCru  
fOMvj%T@2  
zBe8,, e  
/* :=[XW?L%x  
**Utility.java n8D xB@DI  
*/ KFFSv{m[  
package NetFox; |K|h+fgG6*  
g'|MA~4yB  
3dRr/Ilc  
public class Utility { cJL'$`gWf  
I;1lX L  
?A )hN8  
public Utility() &[ ;HYgp  
{ MKWyP+6`  
[/BE8]M ~  
Y>&Ew*Y  
} Z"uY}P3  
.fdL&z  
//线程睡眠 _X'"w|0  
public static void sleep(int nSecond) PfZ+PqS  
{ [Ts"OPb% ~  
try{ hjQ~uqbg  
Thread.sleep(nSecond); I*`*Q$  
} h`H,a7  
catch(Exception e) +fnK /%b  
{ PxfY&;4n!  
e.printStackTrace (); z$kenhFG/  
} J:kmqk!  
} Yp:KI7  
($~RoQ=0S  
//日志 Y)}Rb6qGW  
public static void log(String sMsg) s$a09x  
{ iIP8`! O  
System.err.println(sMsg); g{P%s'%*  
} fa<v0vb+  
eEn;!RS)  
bk\yCt06y;  
public static void log(int sMsg) VV9_`myN7  
{ -k7X:!>QHC  
System.err.println(sMsg); bHI<B)=`  
} V,[d66H=N  
} -c}, :G"  
+(+Itmx2&  
7H|$4;X^  
/* 5Fz.Y}  
**TestMethod.java =lu/9 i6  
*/ @_LN3zP  
package NetFox; g=e71DXG2  
<Engi!  
_{ZqO;[u  
public class TestMethod { %=BMZRn  
EKz Ad  
&RTX6%'KY  
public TestMethod() z1Ov|Q`  
{ ///xx/weblogic60b2_win.exe ~D|5u\D-  
try{ +EAT:,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Uk,g JR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <3j"&i]Tm*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); k{<,\J  
fileFetch.start(); ;-Jb1"5  
} ScSZGs 5&  
catch(Exception e){e.printStackTrace ();} "$}vP<SM  
"XT"|KF|D  
1\r|g2Z :  
} 9Fr3pRIJ  
>X51$wBL  
%b^OeWip  
public static void main(String[] args) MW+b;0U`#  
{ p^pOuy8  
new TestMethod(); OGY"<YH6  
} chEn|>~  
} 41_SRh7N  
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