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http断点续传简单实现(java)

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/* p18-yt; 1  
**SiteFileFetch.java #HWz.Wb  
*/ X5U_|XK6Y  
package NetFox; T#6']D  
import java.io.*; 7s; <5xc  
import java.net.*; 5#g<L ~  
fO[X<|9  
`J[(Dx'y=t  
public class SiteFileFetch extends Thread { G]E$U]=9r:  
>"jV8%!sM  
v]F q}I"  
SiteInfoBean siteInfoBean = null; //文件信息Bean N~{0QewMI'  
long[] nStartPos; //开始位置 ;@Ep?S @  
long[] nEndPos; //结束位置 z{pNQ[t1Z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6[$kEKOY=  
long nFileLength; //文件长度 wYSvI  
boolean bFirst = true; //是否第一次取文件 4q/E7n  
boolean bStop = false; //停止标志 Fkuq'C<|Y  
File tmpFile; //文件下载的临时信息 D;Fvd:  
DataOutputStream output; //输出到文件的输出流 >9a%"<(2#  
V"%2Tz  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) I+D`\OSL  
public SiteFileFetch(SiteInfoBean bean) throws IOException KSIH1E  
{ s=(~/p#M  
siteInfoBean = bean; I{<6GIU+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); kQC>8"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); bR?-B>EB  
if(tmpFile.exists ()) N?Mmv|  
{ Jc~^32  
bFirst = false; 1)/B V{n  
read_nPos(); Jme}{!3m  
} B/q/sC  
else kF3 EJ  
{ 8R`@edj>  
nStartPos = new long[bean.getNSplitter()]; |2CW!is  
nEndPos = new long[bean.getNSplitter()]; (6A>:_)  
}  twz  
9<kKno  
)PL'^gR r  
:>nk63V (  
} aw/Y#  
 4D"IAI  
|}^[f]  
public void run() 6R%c+ok8i  
{ EAF<PMb  
//获得文件长度 I|RN/RVN  
//分割文件 =}\]i*  
//实例FileSplitterFetch j$T2ff6  
//启动FileSplitterFetch线程 M~I M;my  
//等待子线程返回 2]eh[fRQ  
try{ $qD8vu )|j  
if(bFirst) q?[{fcNh$  
{ d%1S6eYa'  
nFileLength = getFileSize(); G(JvAe]r  
if(nFileLength == -1) %83PbH  
{ u9:;ft{}N  
System.err.println("File Length is not known!"); 'Vy$d<@s[  
} reM%GU  
else if(nFileLength == -2) fbB(W E+  
{ |4-c/@D.~  
System.err.println("File is not access!"); 4en&EWUr  
} uQ&&? j  
else -}{\C]%  
{ ^4Tr @g#]"  
for(int i=0;i<nStartPos.length;i++) }CsUZ&*&  
{ 5U|f"3&8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ijr*_=  
} [4kx59J3b  
for(int i=0;i<nEndPos.length-1;i++) :|<D(YA  
{ lcJ`OLG  
nEndPos = nStartPos[i+1]; ll1?I8}5|  
} ?8-e@/E#x  
nEndPos[nEndPos.length-1] = nFileLength; +hY/4Tx<  
} WaWT 5|A  
} dmP*2  
P{(m:`N  
ex'd^y  
//启动子线程 #Q 2$v;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >G' NI?$  
for(int i=0;i<nStartPos.length;i++) `C=!8q  
{ 3, ,Z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $7TYix8=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), uP|AP  
nStartPos,nEndPos,i); Vt n$*ML  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?-#w [J'6  
fileSplitterFetch.start(); +SPC@E_v  
} @WhcY*R2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), akm)X0!-}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xVfJ ]Y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /Ia=/Jj7N  
nEndPos = " + nFileLength); {aGQ[MH\9  
// fileSplitterFetch[nPos.length-1].start(); 1uB}Oe 2~  
Zdh4CNEeFP  
zZDG5_$n  
//等待子线程结束 IZJV6clM  
//int count = 0; eX?o 4>  
//是否结束while循环 kt[#@M!}  
boolean breakWhile = false; sN-5vYfC*  
p]!,Bo ZL  
T]Tz<w W(  
while(!bStop) SnQ$  
{ d#ld*\|  
write_nPos(); 8k_,Hni  
Utility.sleep(500); S wC,=S  
breakWhile = true; *sAoYx  
xhUQ.(S`r6  
8Y5* 1E*  
for(int i=0;i<nStartPos.length;i++) rRT9)wDa  
{ b\=0[kBQw  
if(!fileSplitterFetch.bDownOver) ,"h$!k"$g  
{ `*}#Bks!  
breakWhile = false; )KXLL;]  
break; +]uy  
} !G\1$"T$  
} 8"oS1W  
if(breakWhile) w$Dp m.0(  
break; Vy}:Q[  
w/YKWv{_S  
4yRT!k}o  
//count++; Ba`]Sm=  
//if(count>4) bXJ,L$q  
// siteStop(); C!qW:H  
} xBB:b\  
WpTC,~-  
%*|XN*iXC  
System.err.println("文件下载结束!"); yc%AkhX*  
} 14oD^`-t  
catch(Exception e){e.printStackTrace ();} fD,#z&  
} 3XL0Pm  
QR4v6*VpD  
Yo7ctwzdH;  
//获得文件长度 @q^WD_k  
public long getFileSize() #\`6ZHW  
{ gkBat(Uc  
int nFileLength = -1; H[-zQ#I9  
try{ O,^,G<`  
URL url = new URL(siteInfoBean.getSSiteURL()); >IoOCQQ*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !m_'<=)B4~  
httpConnection.setRequestProperty("User-Agent","NetFox"); z w5EaY  
j{p0yuZ)<  
).v;~yE   
int responseCode=httpConnection.getResponseCode(); OEB_LI'  
if(responseCode>=400) {\]SvoJnJ  
{ mT!~;] RrF  
processErrorCode(responseCode); F>^k<E?,C  
return -2; //-2 represent access is error w?Q@"^IL  
} IDLA-Vxo  
c (\-7*En  
OmU.9PDg-  
String sHeader; ;y HA.}  
s?0r\cc|:  
QQC0uta`  
for(int i=1;;i++) .Z/"L@  
{ Nkv2?o>l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A\4 Gq  
//Utility.log(in.readLine()); )}paQmy#  
sHeader=httpConnection.getHeaderFieldKey(i); >Pv%E  
if(sHeader!=null) dZnq 96<:|  
{ N.&)22<m9  
if(sHeader.equals("Content-Length")) uX.Aq@j  
{ {Ziq~{W_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); X^aujK^@  
break; QF%@MK0zC  
} &m Y<e4  
} _II;$_N  
else :Ur%.0  
break; (%I`EAR  
} Lo;T\C N  
} =faV,o&{`  
catch(IOException e){e.printStackTrace ();} 7Kh+m@q.  
catch(Exception e){e.printStackTrace ();} tM@TT@.t~  
+ FLzK(  
N4HnW0  
Utility.log(nFileLength); q=96Ci_a  
r/{0Y Fa  
t$Qav>D  
return nFileLength; i ;X'1TN(y  
} -sc@SoS  
hKX-]+6"  
D}3E1`)W  
//保存下载信息(文件指针位置) }r,k*I'K  
private void write_nPos() QV?\?9(  
{ F~* 5`o  
try{ N:&^ql4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *a$z!Ma3h  
output.writeInt(nStartPos.length); V2.MZ9  
for(int i=0;i<nStartPos.length;i++) u_:" u  
{ 0Q>Yoa 11  
// output.writeLong(nPos); hV=)T^Q  
output.writeLong(fileSplitterFetch.nStartPos); :k(aH Ua  
output.writeLong(fileSplitterFetch.nEndPos); ["@K~my~D*  
} lHP[WO  
output.close(); 8.9S91]=  
} 1h)I&T"kZ  
catch(IOException e){e.printStackTrace ();} Gia_B6*Y[  
catch(Exception e){e.printStackTrace ();} oq0G@  
} 0eUsvzz 15  
B}*xrPj  
N2~DxVJ5cT  
//读取保存的下载信息(文件指针位置) $e<3z6  
private void read_nPos() kA#>Xu/  
{ a&y%|Gs^f  
try{ Bd\p!f<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2abWIw4  
int nCount = input.readInt(); d_]MqH>R\  
nStartPos = new long[nCount]; JsiJ=zo<  
nEndPos = new long[nCount]; l&T;G 9z  
for(int i=0;i<nStartPos.length;i++) n{UB^-}5  
{ 8+GlM+>4  
nStartPos = input.readLong(); Pb[wysy  
nEndPos = input.readLong(); ,T1 t`  
} eqjl$QWPJS  
input.close(); r!#a.  
} L4Kkbt<x  
catch(IOException e){e.printStackTrace ();} eOLS  
catch(Exception e){e.printStackTrace ();} nk6xavQji  
} r[~K m5  
NCl={O9<j  
.Olq_wuH  
private void processErrorCode(int nErrorCode) >eJk)qM  
{ b`%/ *  
System.err.println("Error Code : " + nErrorCode); f+gyJ#R`  
} *+Q,b^N  
TQnMPELh"  
'VO^H68  
//停止文件下载 PW.W.<CL  
public void siteStop() Fdvex$r&  
{ <4(rY9   
bStop = true; 30F&FTW  
for(int i=0;i<nStartPos.length;i++) V-I_SvWv\  
fileSplitterFetch.splitterStop(); w"A'uFXLc  
5N ' QG<jE  
T_I"Tsv  
} SD JAk&Z}R  
} >Wy@J]Y#  
//负责部分文件的抓取 IURi90Ir  
**FileSplitterFetch.java =DF7l<&km  
*/ [n66ZY#U]  
package NetFox; +KD~/}C%-  
u^V`Ucd"R  
vp-)$f&  
import java.io.*; Pk*EnA)  
import java.net.*; 5z#>>|1>#  
-*tP_=-Dg  
\.Q"fd?a_D  
public class FileSplitterFetch extends Thread { a"hlPJlG  
WO_cT26Y  
&a-:ZA@  
String sURL; //File URL 6)DYQ^4y  
long nStartPos; //File Snippet Start Position Z mYp!B_~  
long nEndPos; //File Snippet End Position 9h~>7VeZ)  
int nThreadID; //Thread's ID b/ur!2yr  
boolean bDownOver = false; //Downing is over P3@[x  
boolean bStop = false; //Stop identical OGh b Ha  
FileAccessI fileAccessI = null; //File Access interface v>0xHQD*<M  
TX8,+s+  
@\[&_DZ  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gxL5%:@  
{ HiVF<tN  
this.sURL = sURL; K3 "co1]u  
this.nStartPos = nStart; n_?<q{GW  
this.nEndPos = nEnd; A^o  
nThreadID = id; :^?ZVi59j  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2rD`]neA  
} f*kT7PJG  
30[?XVI&  
H VG'v>s@  
public void run() KqaeRs.u  
{ aoMQ_@0  
while(nStartPos < nEndPos && !bStop) RI cA)I.  
{ zneK)C8&q3  
P1H`NOC  
1>l {c  
try{ oREZ^pE@  
URL url = new URL(sURL); nG{j x_{`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J&Le*R'  
httpConnection.setRequestProperty("User-Agent","NetFox"); voV=}.(p  
String sProperty = "bytes="+nStartPos+"-"; ;>|:I(l;  
httpConnection.setRequestProperty("RANGE",sProperty); ILTd*f  
Utility.log(sProperty); I)DLnnQQ  
j3z&0sc2(0  
o_os;  
InputStream input = httpConnection.getInputStream(); &|Z:8]'P  
//logResponseHead(httpConnection); T4qbyui{  
ugucq},[  
6}{2W<  
byte[] b = new byte[1024]; Jp_{PR:&  
int nRead; F]SexP4:A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) E}\^GNT  
{ QT\S>}  
nStartPos += fileAccessI.write(b,0,nRead); Q_LPLmM  
//if(nThreadID == 1) IN`05Q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fm:/}7s  
} y&9v0&o  
+<@7x16  
"D8x HHb  
Utility.log("Thread " + nThreadID + " is over!"); uXu'I  
bDownOver = true; q^Oq:l$s  
//nPos = fileAccessI.write (b,0,nRead); N$?mula  
} 7P:0XML}  
catch(Exception e){e.printStackTrace ();} Yq<D(F#qx  
} :]e:-JbT4z  
} OFCkQEG=y>  
QQ1+uY  
A3yVT8  
//打印回应的头信息 A$fd6+{  
public void logResponseHead(HttpURLConnection con) 6$ @Pk<w  
{ rb&^ei9B  
for(int i=1;;i++) 1OE^pxfi>  
{ &RpQ2*4n  
String header=con.getHeaderFieldKey(i); A CJmy2  
if(header!=null) BJ~Q\Si6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~F>oNbJIv  
Utility.log(header+" : "+con.getHeaderField(header)); u.8vXc  
else )d0&iE`@  
break; k/!Vv#8  
} w0tlF:Eg  
} c3i|q@ k  
e +4p__TmZ  
^/mQo`[G  
public void splitterStop() LQNu]2  
{ m7^a4  
bStop = true; g|e^}voRM  
} `=b*g24z[N  
NZ9`8&93  
J'^BxN&  
} SM! [ yC  
F)5QpDmqb  
1H-R-NNJ:  
/* RYS]b[-xZz  
**FileAccess.java JB''Ujyi  
*//文件访问(定位,写) 9v 0.]  
package NetFox; =5I1[p;  
import java.io.*; 6DR@$fpt  
@l>\vs<  
(al7/EhY  
public class FileAccessI implements Serializable{ fZxZ):7i  
Nki18ud#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 iN+p>3w^l  
RandomAccessFile oSavedFile; mcS/-DaN?  
long nPos; U|-4*l9Ed  
KW^s~j  
VlXIM,  
public FileAccessI() throws IOException Z]uN9c  
{ $//18+T  
this("",0); N, ;'oL+  
} ^7F!>!9Ca  
fcD$km  
u%VO'}Gz  
public FileAccessI(String sName,long nPos) throws IOException BAdHGwomh  
{ k[y{&f,  
oSavedFile = new RandomAccessFile(sName,"rw"); 6~;fj+S  
this.nPos = nPos; a5L#c=  
oSavedFile.seek(nPos); 'rp(k\ pY  
} -md2Z0^ Kc  
dGP*bMCT  
L.l%EcW=,  
public synchronized int write(byte[] b,int nStart,int nLen) _BtppQIWv  
{ +7N6]pK|"  
int n = -1; ZCbxL.fFz  
try{ m$pXe<  
oSavedFile.write(b,nStart,nLen); @\u)k  
n = nLen; %jKR\f G  
} @Eqc&v!O  
catch(IOException e) g%1!YvS3v  
{ 91mXvQ:u  
e.printStackTrace (); #x)G2T'?  
} V{ra,a*  
}_@cqx:n^  
 6:ZqS~-  
return n; #}:VZ2Z  
} "g>uNtt~  
( F0.lDZ  
sjWhtd[fgG  
} 2"yzrwZ:  
D#W{:_f  
n_.2B$JD  
/* 8[(c'rl|)|  
**SiteInfoBean.java u2JkPh&!rq  
*/ X[h=UlF  
package NetFox; h8u(lIRHQ  
<u u1e@P  
-NiFO  
public class SiteInfoBean { A{y3yH`#h  
3vQ?vS|2  
hY-;Wfg  
private String sSiteURL; //Site's URL |KplbU0iC  
private String sFilePath; //Saved File's Path TjgX' j  
private String sFileName; //Saved File's Name 4kxy7] W  
private int nSplitter; //Count of Splited Downloading File :NA cad  
<kPU*P,  
`^wF]R  
public SiteInfoBean() j05ahquI  
{//nSplitter的缺省值为5  ZMg%/C  
//default value of nSplitter is 5 i ,4  
this("","","",5); *=~ 9?  
} 2=(=Wjk.  
[q9TTJ@2  
A6q,"BS^d  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) f.V0uBDN  
{ qaG%PH}a  
sSiteURL= sURL; P,_GTs3/G  
sFilePath = sPath; *)L%pH>`  
sFileName = sName; D@>P%k$$s>  
this.nSplitter = nSpiltter; &tLg}7?iB  
>pG]#Z g  
u;h9Ra1  
} = Ky1v$<  
\P&'4y~PL  
EG7ki0  
public String getSSiteURL() y 9/27yWB  
{ $hg W>e  
return sSiteURL; ^p|@{4f]  
} P ,xayy  
h"#^0$f  
0Q]x[;!k  
public void setSSiteURL(String value) - Kj$A@~x  
{ ,UH`l./3DX  
sSiteURL = value; o=w& &B  
} PKwHq<vAsB  
PX\}lTJ  
pc^(@eD  
public String getSFilePath() Rj^bZ%t  
{ ,yAvLY5 P  
return sFilePath; Ga N4In[d  
} rQj.W6w=  
lv&<kYWY  
]1abz:  
public void setSFilePath(String value) 31Zl"-<#-  
{ +%UXI$v  
sFilePath = value; VP0wa>50!  
} ? Yy[8_(tN  
7EQ |p  
(+CB)nV0IA  
public String getSFileName() D GOc!  
{ 7KuTC%7  
return sFileName; '#u |RsZ  
} DWm$:M4 z  
y9Yh%M(  
[AE]0cO@  
public void setSFileName(String value) L7q%u.nB1  
{  6>Lr  
sFileName = value; c}g^wLa  
} q,0o:nI  
mBQ6qmK   
]*[S# Jk  
public int getNSplitter() 3$(1LN  
{ E-.M+[   
return nSplitter; 'S@h._q  
} QmbD%kW`3  
b==<7[8  
7!Ym~M=  
public void setNSplitter(int nCount) o LuGW5wzj  
{ *1Nz VV  
nSplitter = nCount; 5c3 )p^ ]g  
} C1r]kF  
} k2 k/v[60  
*oZBv4Vh   
_d %H;<_  
/* ,F6i5128{  
**Utility.java l')?w]|  
*/ kX+y2v(2++  
package NetFox; w KXKc\r  
KosAc'/ M  
vT\`0di~  
public class Utility { ;w}ZI<ou  
K}&|lCsb  
\Ao M'+  
public Utility() iNd 8M V  
{ }y x'U 3  
0K@s_C=n#  
P]j{JL/g&  
} M:Xswwq  
x_2 [+Ol  
//线程睡眠 pRPz1J$58  
public static void sleep(int nSecond) y5BNHweaRb  
{ 8iqx*8}  
try{ o_b j@X  
Thread.sleep(nSecond); /DQoM@X  
} 9_ KUUA  
catch(Exception e) 1;]cYIq  
{ MftX~+  
e.printStackTrace (); F>96]71 2  
} qZ6P(5X  
} w[~$.FM/  
v&xk?F?WU,  
//日志 X<#Q~"  
public static void log(String sMsg) z<sf}6q  
{ |XLx6E2F  
System.err.println(sMsg); ~y$B #.l  
} %RdCSQ9~  
-9.S?N'T>;  
tm#T8iF  
public static void log(int sMsg) NVcL9"ht*@  
{ %fJ*Ql4M  
System.err.println(sMsg); .Rd@,3  
} Beiz*2-}a  
} xzz[!yJjG  
azS"*#r6}  
0p*(<8D}  
/* dfO@Yo-?*'  
**TestMethod.java `:}GE@]  
*/ |A 8xy#  
package NetFox; 4F??9o8}  
)l\BZndf  
H}dsd=yO  
public class TestMethod { do+HPnfDzU  
tceQn ^|<  
5m=3{lBi  
public TestMethod() *&% kkbA  
{ ///xx/weblogic60b2_win.exe 8ooj)  
try{ 9"I/jd0B  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); b_W0tiyv%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vp[~%~1(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); esLPJx  
fileFetch.start(); kzbgy)PK3  
} q/XZb@rt  
catch(Exception e){e.printStackTrace ();} Pi40w+/  
>]&LbUW+  
{h7*a=  
} 600-e;p  
BN|+2D+S  
#T99p+O  
public static void main(String[] args) Hhx<k{B@7  
{ ,fT5I6l  
new TestMethod(); S^c5  
} RI')iz?  
} vaxNF%^~yN  
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