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http断点续传简单实现(java)

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/* LV`- eW  
**SiteFileFetch.java S!rUdxO  
*/ 7/Ew(X8Fs  
package NetFox; CvlAn7r,@  
import java.io.*; ofS9h*wrJ  
import java.net.*; ao 32n  
m^p Q55,   
fz<Y9h=  
public class SiteFileFetch extends Thread { _oR6^#5#  
 =#8J9  
NAL%qQ  
SiteInfoBean siteInfoBean = null; //文件信息Bean \@5W&Be^  
long[] nStartPos; //开始位置 $U!w#|&  
long[] nEndPos; //结束位置 N:=D@x~]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 d ;ry!X  
long nFileLength; //文件长度 H.'_NCF&;L  
boolean bFirst = true; //是否第一次取文件 Lc+)#9*d  
boolean bStop = false; //停止标志 iTD{  
File tmpFile; //文件下载的临时信息 / Z \zB  
DataOutputStream output; //输出到文件的输出流 I_v]^>Xw  
1298&C@  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) /K'Kx  
public SiteFileFetch(SiteInfoBean bean) throws IOException F*} b),  
{ 3<B{-z  
siteInfoBean = bean; <;M6s~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yl|+D]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2f F)I&  
if(tmpFile.exists ()) P^+Og_$  
{ *,mbZE=<  
bFirst = false; n1$p esr  
read_nPos(); 2_UH,n  
} 5JQq?e)n  
else cpf8f i  
{ Z3 &8(vw  
nStartPos = new long[bean.getNSplitter()]; YAsvw\iseK  
nEndPos = new long[bean.getNSplitter()]; )\p@E3Uxf  
} J0^p\mG  
vw3%u+Z&  
B f[D&O  
&AA u:  
} MiN68x9  
gn7pIoN  
76xgExOU?C  
public void run() 3vDV   
{ ;9d(GP}eE  
//获得文件长度 .] 5&\  
//分割文件  Q"%L  
//实例FileSplitterFetch J>x)J}:;  
//启动FileSplitterFetch线程 v^JyVf>  
//等待子线程返回 %J3#4gG^v  
try{ r0?`t!% V  
if(bFirst) PE+N5n2Tl  
{ eF!c< Kcr  
nFileLength = getFileSize(); <#sB ;  
if(nFileLength == -1) RDk{;VED{  
{ S =eP/  
System.err.println("File Length is not known!"); *9*6n\~aI  
} ">NBPanJ  
else if(nFileLength == -2) <Eq^r h  
{ rXvvJIbi  
System.err.println("File is not access!"); l0Y(9(M@  
} foaNB=,  
else ai#0ZgO  
{ ^h=;]vxO  
for(int i=0;i<nStartPos.length;i++) 7?b'"X"  
{ Kq{9 :G  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6<FJ`l]U9  
} E9QNx6 2  
for(int i=0;i<nEndPos.length-1;i++) ,odjL6u  
{ aZ#c_Q#gZ  
nEndPos = nStartPos[i+1]; 2i8'*L+j  
} B +_D*a  
nEndPos[nEndPos.length-1] = nFileLength; u]CW5snz  
} SC"=M^E  
} [R6du*P  
i7:j(W^I8  
Pqx=j_st  
//启动子线程 8%I4jL<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *(s)CWf  
for(int i=0;i<nStartPos.length;i++) Wv$e/N`l  
{ 5zfPh`U>1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ExV>s*y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), GiI2nHZc  
nStartPos,nEndPos,i); c7'I'~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q48V|6X'q  
fileSplitterFetch.start(); z&9vKF  
} w9l)=[s=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;%hlh)k$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :E]A51  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X2T)]`@  
nEndPos = " + nFileLength); 5>"-lB &  
// fileSplitterFetch[nPos.length-1].start(); f`P%aX'cBQ  
DYbkw4Z,  
3>/Yku)t  
//等待子线程结束 ?ZE1>L7e  
//int count = 0; 8x[q[  
//是否结束while循环 (H0nO7Bk  
boolean breakWhile = false; (Kv[~W7lb  
cqi: Rj  
$nBzYRc"3  
while(!bStop) M*{ EK  
{ =)(sN"%  
write_nPos(); og!Uq]U/y  
Utility.sleep(500); u%3Z +[  
breakWhile = true; 315Rk!{AJ  
!2$O^ }6"  
\} P}H  
for(int i=0;i<nStartPos.length;i++) OT\[qaK  
{ zT`LPs6T  
if(!fileSplitterFetch.bDownOver) l^WFMeMD3a  
{ , B h[jb`y  
breakWhile = false; [uW{Ap~2  
break; qP*$wKY,  
} :1s6h%evrT  
} #*1\h=bzmW  
if(breakWhile) i{ eDV  
break; qGr(MDLc  
KKl8tI\u~  
>Ix)jSNLgo  
//count++; 9^3y\@ m  
//if(count>4) 7YkxIzE  
// siteStop(); {pm>F}Cwy  
} ]7fqVOiOu  
rW&8#&  
>& \QLo[5  
System.err.println("文件下载结束!"); 4Ts5*_  
} 83Bp_K2\  
catch(Exception e){e.printStackTrace ();} n\ZDI+X  
} 9=K=gfZ  
#p6#,PZ  
5<Xq7|Jt  
//获得文件长度 &iId<.SiJ  
public long getFileSize() Oy&Myjny<  
{ IH'DCY:  
int nFileLength = -1; #=q)>+\  
try{ "#qyX[\  
URL url = new URL(siteInfoBean.getSSiteURL()); 9#@dQ/*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9^c\$"2B  
httpConnection.setRequestProperty("User-Agent","NetFox"); cc Z A  
%, XyhS5[o  
wBA[L}  
int responseCode=httpConnection.getResponseCode(); m+s^K{k}  
if(responseCode>=400) $ GL$ iA  
{ KaZ$!JfT  
processErrorCode(responseCode); 3z!\Z[  
return -2; //-2 represent access is error 2~K.m@U}!Z  
} K9;pX2^z9  
Sz.jv#Y  
=pF 6  
String sHeader; LTm2B_+  
.UU BAyjm  
'&xv)tno  
for(int i=1;;i++) K\`L>B. 1  
{ #y~^!fdp9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); x$cs_q]J  
//Utility.log(in.readLine()); GBGGV#_q'}  
sHeader=httpConnection.getHeaderFieldKey(i); ?Xx,[Z&  
if(sHeader!=null) (sq4  
{ ??CtmH  
if(sHeader.equals("Content-Length")) o>';-} E  
{ 2$jTj<.K  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Z1wN+Y.CA  
break; oL2|@WNj,  
} o=X6PoJ N_  
} {]n5h#c 5*  
else 1t WKH  
break; $,bLK|<hi  
} 6OkN(tL&.  
} _iO,GT=J-  
catch(IOException e){e.printStackTrace ();} =P<gZ-Cm  
catch(Exception e){e.printStackTrace ();} Wt"fn&R}  
A<C`JN}  
:lcZ )6&S  
Utility.log(nFileLength); S2HGf~rE  
&s>HiL>f  
"~jt0pp  
return nFileLength; .#2YJ~  
} Q *![u5#  
\`-/\N  
>sv|  
//保存下载信息(文件指针位置) y<.0+YL-e+  
private void write_nPos() (A}##h  
{ HW;,XzP=  
try{ ;X[mfg\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); [k ZvBd  
output.writeInt(nStartPos.length); 6'3@/.  
for(int i=0;i<nStartPos.length;i++) w*Vf{[a'  
{ uHkL$}C  
// output.writeLong(nPos); %K@D{ )r_^  
output.writeLong(fileSplitterFetch.nStartPos); G9TK)Nz  
output.writeLong(fileSplitterFetch.nEndPos); -n?}L#4%8  
} hu%UEB  
output.close(); RXP0 4  
} U N1HBW;  
catch(IOException e){e.printStackTrace ();} : |#Iw  
catch(Exception e){e.printStackTrace ();} )@DH&  
} rDX_$,3L  
Z$ {I 4a  
,^3eMn  
//读取保存的下载信息(文件指针位置) {s6;6>-kPW  
private void read_nPos() 9[N+x2q  
{ lX/6u E_%  
try{ J@54B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,3Y~ #{,i  
int nCount = input.readInt(); gk>-h,>"  
nStartPos = new long[nCount]; 1a;Le8  
nEndPos = new long[nCount]; zRbooo{N  
for(int i=0;i<nStartPos.length;i++) JV=d!Gi[C  
{ L1D{LzlBti  
nStartPos = input.readLong(); b*LEoQSl0V  
nEndPos = input.readLong(); >:%i,K*AM  
} &~ QQZ]q6  
input.close(); I2hX;pk,  
} "Sz pFw  
catch(IOException e){e.printStackTrace ();} ;aExEgTq  
catch(Exception e){e.printStackTrace ();} lJP6s k  
} 6TvlK*<r=  
e; 5 n.+m  
=W"BfG  
private void processErrorCode(int nErrorCode) v|C)Q %v  
{ m=b~Wf39  
System.err.println("Error Code : " + nErrorCode); lG;RfDI-  
} X3vTyIsn  
uvz}qH@j/Q  
eN fo8xUG  
//停止文件下载 7d*SZmD  
public void siteStop() Ml1yk)3G  
{ -g(&5._,ZW  
bStop = true; uh*b[`e  
for(int i=0;i<nStartPos.length;i++) E}sj l  
fileSplitterFetch.splitterStop(); <"Z]S^>$  
Adp:O"-H1o  
# 8 0DM  
} }2:/&H'  
} Y O;N9wu3f  
//负责部分文件的抓取 Sd'!(M^k3  
**FileSplitterFetch.java dtw1Am#Ci  
*/ ; {$9Sc $  
package NetFox; SUsD)!u_H  
s,XKl5'+8e  
pV]m6! y&  
import java.io.*; 3YVG|Bc~_  
import java.net.*; n0q5|ES  
r e.chQ6  
Nlemb:'eP3  
public class FileSplitterFetch extends Thread { 3 &.?9  
mE^mQ [Dk  
?W-J2tgss{  
String sURL; //File URL [0U!Y/?6lA  
long nStartPos; //File Snippet Start Position ;A7HEx  
long nEndPos; //File Snippet End Position Ymkk"y.w  
int nThreadID; //Thread's ID 5<\&7P3y  
boolean bDownOver = false; //Downing is over Y0fX\6=h  
boolean bStop = false; //Stop identical xZZW*d_b  
FileAccessI fileAccessI = null; //File Access interface Is&z~Xy/  
ESp)%  
~n9BN'@x  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException L!s/0kBg  
{ < ek_n;R  
this.sURL = sURL; *jM~VTXwt  
this.nStartPos = nStart; aRPgo0,W1  
this.nEndPos = nEnd; yb*P&si5bY  
nThreadID = id; ]`)50\pdw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Mk9'  
} pt.0%3  
8gwJ%"-K  
 5 fY\0  
public void run() ,6:ya8vB  
{ n=!]!'h\:  
while(nStartPos < nEndPos && !bStop) $o"S zy  
{ V1 T?T9m  
1^ZQXUzl%i  
(oO*|\9u  
try{ ImO\X`{  
URL url = new URL(sURL); 3on]#/"1b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )X2=x^u*U  
httpConnection.setRequestProperty("User-Agent","NetFox"); u~FXO[b  
String sProperty = "bytes="+nStartPos+"-"; rt)70=  
httpConnection.setRequestProperty("RANGE",sProperty); &^$dHr6v  
Utility.log(sProperty); fr kDf-P  
t<s:ut)Q!  
zBD ?O!  
InputStream input = httpConnection.getInputStream(); N)|mA)S)  
//logResponseHead(httpConnection); L1ZhH3}X  
n*~=O'  
W<C \g~\  
byte[] b = new byte[1024]; ,DsqKXSU  
int nRead; rKEi1b  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) D{g6M>,\  
{ +ptVAg+  
nStartPos += fileAccessI.write(b,0,nRead); k?ubr)[)  
//if(nThreadID == 1) U/'"w v1y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x LR 2H>B}  
} Ex2TV7I  
<+@?V$&  
Qz/o-W;  
Utility.log("Thread " + nThreadID + " is over!"); ZlD\)6 dZ  
bDownOver = true; C%#=@HC  
//nPos = fileAccessI.write (b,0,nRead); 'lNy&  
} ; mnV)8:F  
catch(Exception e){e.printStackTrace ();} ^Uss?)jN4  
} 17g\XC@ Cl  
} S^0Po%d  
rUvjc4O}  
_1jd{? kt  
//打印回应的头信息 Z]f_? @0  
public void logResponseHead(HttpURLConnection con) P @N7g`u3}  
{ >MD['=J[d  
for(int i=1;;i++) 6U[`CGL66  
{ t=M:L[bis;  
String header=con.getHeaderFieldKey(i); R{Q*"sf  
if(header!=null) U5Say3r  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); R&}"En`$s  
Utility.log(header+" : "+con.getHeaderField(header)); ]G.ttfC  
else :ad  
break; |hms'n0  
} K s 8  
} G?D7R/0)  
l",JN.w  
*6D0>F  
public void splitterStop() _aa3;kT_  
{ 1|$V  
bStop = true; B1dVHz#  
} L1=+x^WQ  
;Q"xXT`;:  
Ay\=&4dv  
} *ue- x!"c  
/Y$UJt  
eF+:w:\h  
/* g-`HKoKe  
**FileAccess.java bH4'j/3  
*//文件访问(定位,写) hu}`,2  
package NetFox; V5w00s5?%  
import java.io.*; G"w ?{W @  
0kxo  
K=,nX7Z5  
public class FileAccessI implements Serializable{ )p*I(y  
VN!`@Ci/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 xCU^4DO3p  
RandomAccessFile oSavedFile; q =sEtH=  
long nPos; ":s1}A  
K;,zE6WD$$  
lbM)U  
public FileAccessI() throws IOException A[lbBR  
{ d%1Tv1={  
this("",0); p!qV!:  
} Ip#BR!$n  
xs+pCK|  
0/{$5gy&  
public FileAccessI(String sName,long nPos) throws IOException `K -j  
{ AX6z4G  
oSavedFile = new RandomAccessFile(sName,"rw"); HKu? J  
this.nPos = nPos; f Z8%Z   
oSavedFile.seek(nPos); x'IVP[xh`A  
} 8m% +O#  
)I7~ <$w  
4C@ .X[r  
public synchronized int write(byte[] b,int nStart,int nLen) wdS4iQD  
{ b=nQi./f  
int n = -1; =`RogjbP  
try{ #[ZF'9x  
oSavedFile.write(b,nStart,nLen); Ik[aiz  
n = nLen; Ay?KE{Qs '  
} B \?We\y  
catch(IOException e) &o{=  
{ ~ *:{U   
e.printStackTrace (); nnr g^F  
} `/]Th&(5  
#p'Xq }]  
+ob<? T  
return n; 9 0PF)U  
} tQ!p<Q= $)  
ee7#PE]}  
|'@c ~yc  
} `PML 4P[  
}dnO7K  
I+nKaN+8i  
/* kU uDA><1  
**SiteInfoBean.java +/!kL0[v  
*/ +; /]'  
package NetFox; \:>GF-Z(  
VVY#g%(K  
qg521o$*  
public class SiteInfoBean { $ = uz  
yGGQ;!/  
B[XVTok  
private String sSiteURL; //Site's URL {+D 6o  
private String sFilePath; //Saved File's Path E?$|`<o{|`  
private String sFileName; //Saved File's Name %:61@<  
private int nSplitter; //Count of Splited Downloading File tE&@U$0>o  
""AP-7  
BS-nny  
public SiteInfoBean() w[`2t{^j  
{//nSplitter的缺省值为5 Po+I!TL'  
//default value of nSplitter is 5 y3!r;>2k=  
this("","","",5); Fk&W*<}/;  
} 5Q_ T=TL  
QGv$~A[h  
D,cGW,2Nv  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Kob i!  
{ Af *e:}}  
sSiteURL= sURL; rByC6HV"  
sFilePath = sPath; -e#~CE-  
sFileName = sName; pwj?  
this.nSplitter = nSpiltter; w5j6RQml  
*g0}pD;r  
Y&vn`#   
} $U3|.4  
P''5A6#5  
Cs2hi,s  
public String getSSiteURL() .MoOjx?  
{ \*>r[6]*&5  
return sSiteURL; ~3]ZN'b\  
} 93Z/|7  
&b!L$@6  
!m7`E  
public void setSSiteURL(String value) ].E89_|O  
{ P'EPP*)q  
sSiteURL = value; N?Wx-pK  
} X<pg^Y0  
>[,ywRJ#_}  
h6Femis  
public String getSFilePath() /(/Z~J[  
{ d! BQ%a  
return sFilePath; C!]R0L*  
} KyQO>g{R  
JnC$}amr  
{2|[7oNT6  
public void setSFilePath(String value)  z]/;?  
{ "6[a%f#Q  
sFilePath = value; {zTo[i  
} B8XW+U  
A`|Z2  
ld RV JVZc  
public String getSFileName() J[Ck z]  
{ <>gX'te  
return sFileName; TH;kJ{[}  
} ny(`An  
;$`5L"I5$  
' 7lHWqN<  
public void setSFileName(String value) 4*j6~  
{ |@84l  
sFileName = value; l|, Hj  
} o'oA.'ul  
(8Q0?SZN  
% oPt],>  
public int getNSplitter() {P'_s ]B)  
{ 5y 9(<}z  
return nSplitter; @W4tnM,#  
} VR8 kY&  
HDmjt+3&n  
S JseP_-  
public void setNSplitter(int nCount) GJu[af  
{ <7U\@si4  
nSplitter = nCount; LB(I^  
} \&{a/e2:S  
} M2pe*z  
>9WJa5{  
SG5GJCkc  
/* [`F}<L."  
**Utility.java 4AIo,{(  
*/ 5%qq#;[ n  
package NetFox;  X.q,  
9.:]eL  
&dH[lB  
public class Utility { 5Kadh2nz  
Aof)WKo  
R6(sWN-  
public Utility() \ F\ /<  
{ e_<'zH_1  
QLs9W& PG  
0XcH  
} $ \yZ;Z:  
p)u?x)w=  
//线程睡眠 Po)!vL"   
public static void sleep(int nSecond) j&(Yk"j+  
{ Ipp#{'Do  
try{ $dxk;V  
Thread.sleep(nSecond); |41NRGgY  
} $wr B5m?  
catch(Exception e) KQf=t0Z=Ce  
{ m{ wk0  
e.printStackTrace (); D]?eRO9'  
} f3>L/9[[<P  
} y ;\m1o2  
65HP9`5Tm  
//日志 Z! /!4(Fh  
public static void log(String sMsg) Q!91uNL  
{ v)f;dq^z-  
System.err.println(sMsg); <:n !qQS6  
} ]+"25V'L  
3} 7`?$ 5  
!J6;F}Pd/  
public static void log(int sMsg) '%H\ k5^  
{ zu,F 0;De  
System.err.println(sMsg); <M y+!3\A  
} ?rJe"TOIy  
} y6hb-: #1  
qxQuXF>:#  
<Jf[N=  
/* I[l8@!0  
**TestMethod.java f}!Eu  
*/ X([8TR  
package NetFox; t'e\Z2  
[ ,&O  
Irc(5rD7   
public class TestMethod { ~pC\"LU`  
8v ZY+Q >  
; u@& [  
public TestMethod() t@;r~S b  
{ ///xx/weblogic60b2_win.exe vG{lxPIj  
try{ d:L|BkQ7*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6CV9ewr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); R<)^--n  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .eHOG]H  
fileFetch.start(); :~{Nf-y0`1  
} Q,m&XpZ  
catch(Exception e){e.printStackTrace ();} J#*%r)  
<2V:tj)?P  
MQY}}a-oug  
} P3k@ptc-K  
2.2G79 U,  
u)4eu,MBT  
public static void main(String[] args) \-W|)H  
{ Q1'4xWu  
new TestMethod(); W^k|*Y|  
} 4G_At  
} 3FgTM(  
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