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http断点续传简单实现(java)

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/*  Hi#hf"V  
**SiteFileFetch.java X-=49)  
*/ >HyZ~M  
package NetFox; "d% o%  
import java.io.*; W2'u]1bs  
import java.net.*; N^v"n*M0|  
13kl\ <6  
}Ge$?ZFH  
public class SiteFileFetch extends Thread { UZz/v#y~  
';Y0qitGB  
qf;x~1efC4  
SiteInfoBean siteInfoBean = null; //文件信息Bean !ap}+_IA7^  
long[] nStartPos; //开始位置 9!; /+P  
long[] nEndPos; //结束位置 1N,</<"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]V^ >aUlj  
long nFileLength; //文件长度 `p#tx.o  
boolean bFirst = true; //是否第一次取文件 a[I :^S  
boolean bStop = false; //停止标志 $i1$nc8  
File tmpFile; //文件下载的临时信息 ?L x*MJZ  
DataOutputStream output; //输出到文件的输出流 shKTj5s?  
}20~5!  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) id+ ~ V  
public SiteFileFetch(SiteInfoBean bean) throws IOException  4 Fl>XM  
{ F$M^}vsjGx  
siteInfoBean = bean; !Ah v07SI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); HAwdu1$8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); nvbzCtC  
if(tmpFile.exists ()) u.;l=tzz  
{ i]9C"Kw$L  
bFirst = false; {>g{+Eq  
read_nPos(); Y \Gx|  
} Np7+g`nG  
else 2DU Y4Ti  
{ 'h R0JXy  
nStartPos = new long[bean.getNSplitter()]; jh(T?t$&  
nEndPos = new long[bean.getNSplitter()]; $7" Y/9Y  
} C~Hhi-Xl)  
r3  qKT  
0CO@@`~4  
bMn)lrsX  
} {8>g?4Q#  
D6-R>"}  
9TX2h0U?  
public void run() [;H-HpBaa  
{ R:4@a ':H  
//获得文件长度 JkhWLQ>o  
//分割文件 i-PK59VZ8f  
//实例FileSplitterFetch Bv<aB(c  
//启动FileSplitterFetch线程 Qk? WX (`B  
//等待子线程返回 1w~PHH`~  
try{ 9U8x&Z]P  
if(bFirst) 3\2%i 6W6  
{ @R%* ;)*F  
nFileLength = getFileSize(); ,OWk[0/  
if(nFileLength == -1) f0vO(@I  
{ .fbY2b([  
System.err.println("File Length is not known!"); ^s6}[LDW>@  
}  9u^M{6  
else if(nFileLength == -2) "4\k1H"_  
{ {CV+1kz  
System.err.println("File is not access!"); M!+J[q  
} ^3[_4av  
else NB1KsvD{  
{ b"WF]x|^  
for(int i=0;i<nStartPos.length;i++) Q7rBc wm5  
{ MA,*$BgZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); U$mDAi$  
} 6#7hMQ0&;O  
for(int i=0;i<nEndPos.length-1;i++) yUj`vu 2  
{ >ei~:z]R  
nEndPos = nStartPos[i+1]; k:I,$"y4  
} JcUU#>  
nEndPos[nEndPos.length-1] = nFileLength; T? Kh '  
} g3].STz6w  
} ]L97k(:Ib  
]f#s`.A~  
VE-l6@`  
//启动子线程 XHekz6_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; QuqznYSY{  
for(int i=0;i<nStartPos.length;i++) GA[Ebzi  
{ '{cSWa| #  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @oE 5JM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?OLd }8y  
nStartPos,nEndPos,i); ]R_R`X?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x>}ml\R  
fileSplitterFetch.start(); gzIx!sc  
} 'g!T${  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K_;vqi^1^&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?D6uviQg  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `wXK&R<`  
nEndPos = " + nFileLength); :ZM9lBYh  
// fileSplitterFetch[nPos.length-1].start(); uR ?W|a  
(iX8YP$%  
:D*U4< /u  
//等待子线程结束 ux<|8S  
//int count = 0; l)9IgJ|<b  
//是否结束while循环 . :Skc  
boolean breakWhile = false; eCYPd-d  
5Jbwl$mZ  
iX$G($[l(  
while(!bStop) SI=$s>1  
{ ,B[j{sE  
write_nPos(); <{isWEW9]3  
Utility.sleep(500); !?nbB2,  
breakWhile = true; TI'v /=;)  
2)n`Bd  
#RBrii-,  
for(int i=0;i<nStartPos.length;i++) cD0rU8x  
{ (-gomn  
if(!fileSplitterFetch.bDownOver) M76p=*  
{ CIx(SeEF  
breakWhile = false; t>[W]%op  
break; I8Aq8XBw  
} lI<jYd 0fZ  
} Nap[=[rv  
if(breakWhile) }|.<EkA  
break; &BRk<iwV  
<rBW6o7  
e$Ksn_wEq  
//count++; 6kYluV+j  
//if(count>4) ,^:{!?v  
// siteStop(); suY47DCX)  
} ./#YUIC  
+<a\0FsD  
8K,X3a9  
System.err.println("文件下载结束!"); xDo0bR(  
} lU{)%4e`  
catch(Exception e){e.printStackTrace ();} 5(+9a   
} =Hg!@5]H  
<T}^:2G|  
gXxi; g  
//获得文件长度 ek][^^4o  
public long getFileSize() w:5?ofC  
{ V$?6%\M^*  
int nFileLength = -1; qYK^S4L  
try{ /j~~S'sw  
URL url = new URL(siteInfoBean.getSSiteURL()); csy6_q(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?2]fE[SqY  
httpConnection.setRequestProperty("User-Agent","NetFox"); \Y4(+t=4  
ui%#f1Iq  
}J#HIE\RG  
int responseCode=httpConnection.getResponseCode(); OG5{oH#K  
if(responseCode>=400) q3x"9i `  
{ e$[O J<t  
processErrorCode(responseCode); Nx 42k|8  
return -2; //-2 represent access is error Uu_qy(4  
} i!a!qE.1  
if*V-$[I  
5i[O\@]5  
String sHeader; Z>g72I%X  
74([~Qs _M  
T8S&9BM7  
for(int i=1;;i++) //&3{B  
{ D_l$"35?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `i`P}W!F  
//Utility.log(in.readLine()); Wd'}YbC  
sHeader=httpConnection.getHeaderFieldKey(i); 'gY?=,dF>  
if(sHeader!=null) o@)Fy51DD  
{ G<CD 4:V  
if(sHeader.equals("Content-Length")) d]E=w6 +;Q  
{ Zz0er|9]Q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); y4kn2Mw;  
break; 9C7Npf?~M  
} ntIR#fB  
} v?He]e'  
else y3efie {J  
break; OC&BJNOi  
} -C2!`/U  
} 5Ew( 0K[  
catch(IOException e){e.printStackTrace ();} z};|.N}  
catch(Exception e){e.printStackTrace ();} )7.)fY$  
=X'[r  
XpANaqH\  
Utility.log(nFileLength); X5o*8Bg4M  
Uh0g !zzp  
{iyJ HY  
return nFileLength; lf-.c$.>  
} g[~{iu_$d  
ndFVP;q  
G&h@  
//保存下载信息(文件指针位置) oaj.5hM  
private void write_nPos() :Quep-:fy<  
{ Wrp~OF0k  
try{ nReIi;pi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); VP!4Nob  
output.writeInt(nStartPos.length); 4rDV CXE  
for(int i=0;i<nStartPos.length;i++) T'6`A<`3  
{ 6?x F!VIL  
// output.writeLong(nPos); ;8<HB1 &,  
output.writeLong(fileSplitterFetch.nStartPos); 6D| F1UFU  
output.writeLong(fileSplitterFetch.nEndPos); 4Q!%16 P  
} %f<>Kwr`2  
output.close(); GJWGT`"  
} '9QEG/v  
catch(IOException e){e.printStackTrace ();} N4 x5!00  
catch(Exception e){e.printStackTrace ();} ^Zvb3RJg  
} jUD^]Qs  
g(zeOS]q}  
;'Hu75ymo  
//读取保存的下载信息(文件指针位置) 8 AW}7.<5  
private void read_nPos() Rk5#5R n  
{ t<dFH}U`w  
try{ 4Q#{,y944  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i+(>w'=m  
int nCount = input.readInt(); }J?,?>Z  
nStartPos = new long[nCount]; 7#wB  
nEndPos = new long[nCount]; 5`3 x(=b  
for(int i=0;i<nStartPos.length;i++) HT/!+#W .  
{ @_t=0Rc  
nStartPos = input.readLong(); [ PN2^  
nEndPos = input.readLong(); --diG$x.  
} A3.I|/  
input.close(); )^8[({r~  
} HPu+ 4xQV  
catch(IOException e){e.printStackTrace ();} y =sae  
catch(Exception e){e.printStackTrace ();} }Tk:?U{  
} 0Sk~m4fj(  
I~6(>Z{  
XzIC~}  
private void processErrorCode(int nErrorCode) [f\Jcjc  
{ pq]z%\$u  
System.err.println("Error Code : " + nErrorCode); J;<dO7j5  
} t ]Ln(r  
CH(Y.Kj-  
f6J]=9jU  
//停止文件下载 B#hvw'}  
public void siteStop() "c} en[  
{ LK4NNZf7  
bStop = true; >l8?B L  
for(int i=0;i<nStartPos.length;i++) '4 d4i  
fileSplitterFetch.splitterStop(); W%5))R$  
p2(ha3PW  
[>>_%T\I  
} #5h_{q4l  
} @C^x&Sjm  
//负责部分文件的抓取 A",}Ikh='`  
**FileSplitterFetch.java "*/IP9?]  
*/ `%~}p7Zu  
package NetFox; 5nBJj  
Z&?4<-@6\p  
CB-;Jqb  
import java.io.*; _'Jjt9@S  
import java.net.*; MCTJ^g"D  
G6{'|CV  
WI| -pzg  
public class FileSplitterFetch extends Thread { 3n)Kzexh  
9;I%Dv  
\ :s%;s51  
String sURL; //File URL \VEnP=*:W  
long nStartPos; //File Snippet Start Position %'g)MK!e  
long nEndPos; //File Snippet End Position 2gklGDJD  
int nThreadID; //Thread's ID  |15!D  
boolean bDownOver = false; //Downing is over AH/^v;-  
boolean bStop = false; //Stop identical vO$cF*  
FileAccessI fileAccessI = null; //File Access interface 49>b]f,Vc  
#%ld~dgz-  
l]D $QT3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException r aOuD3  
{ fBZLWfp9  
this.sURL = sURL; "CC"J(&a  
this.nStartPos = nStart; V:j^!*  
this.nEndPos = nEnd; LHx ")H?,  
nThreadID = id; fsK=]~<g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Dz$w6 d  
} 0+qC_ISns  
:4 z\Q]  
]!!?gnPd5  
public void run() KyT=:f V  
{ /N%i6t<xU  
while(nStartPos < nEndPos && !bStop) 8<0P Ssx  
{ U!Zj%H1XQ0  
 h#}w18l  
t\QLj&h}E  
try{ jyF*JQjK4  
URL url = new URL(sURL); e(^I.`9z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _3%:m||,XP  
httpConnection.setRequestProperty("User-Agent","NetFox"); !hfpa_5  
String sProperty = "bytes="+nStartPos+"-"; )lt1I\n*k  
httpConnection.setRequestProperty("RANGE",sProperty); " 1a!]45+  
Utility.log(sProperty); 1}c /l<d  
S-\wX.`R1  
'l!\2Wv2  
InputStream input = httpConnection.getInputStream(); \WnTpl>B  
//logResponseHead(httpConnection); s&o9LdL  
4P)#\$d:  
Sn'!Nq>  
byte[] b = new byte[1024]; =$bF[3D  
int nRead; >Ho=L)u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =AzkE]   
{ 'l\PL1  
nStartPos += fileAccessI.write(b,0,nRead); n2-+.9cY  
//if(nThreadID == 1) %=2sz>M+  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2+)h!y]  
} ; xw9#.d#D  
b@4UR<  
Z/:yYSq  
Utility.log("Thread " + nThreadID + " is over!"); d)biMI}<5  
bDownOver = true; u=s,bt,"5  
//nPos = fileAccessI.write (b,0,nRead); !wd wo0  
} e~)4v  
catch(Exception e){e.printStackTrace ();} q Sv!5&u  
} g%]<sRl:-  
} 2P`./1L  
+?3RC$jyw  
D2D+S  
//打印回应的头信息 "WGKwi=W  
public void logResponseHead(HttpURLConnection con) .WN&]yr,  
{ s/J7z$NEU  
for(int i=1;;i++) 7=X6_AD  
{ T>1#SWQ/9  
String header=con.getHeaderFieldKey(i); iKu3'jZ/O  
if(header!=null) S=V  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); P%yL{  
Utility.log(header+" : "+con.getHeaderField(header)); Yyd}>+|<,  
else AIQ {^:  
break; RWM~7^JA  
} G.XxlI}  
} ;}S_PnwC@  
}0 H<G0   
mP15PZ  
public void splitterStop() 1#"wfiW  
{ 7u^wO<  
bStop = true; ,mCf{V]#  
} F:<+}{Av  
jM6$R1HX  
!U(S?:hvW  
} buzpmRoN)  
LR#.xFQ+  
<)O#Y76s  
/* V?^qW#AG  
**FileAccess.java JF}i=}  
*//文件访问(定位,写) }mZCQJ#`  
package NetFox; @g#| srYD  
import java.io.*; (kK8 OxfF  
Fv/{)H<:y  
dXY}B=C  
public class FileAccessI implements Serializable{ :Zq?V`+M  
Edh9=sxL  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V5h_uGOD  
RandomAccessFile oSavedFile; c??m9=OX1  
long nPos; 30Q77,Nsny  
9_&]7ABV  
@*op5qVw  
public FileAccessI() throws IOException %(? ;`  
{ E:\#Ur2  
this("",0); +ZE"pA^C  
} ],R\oMYy|P  
9 s2z=^  
Bgsi$2hI  
public FileAccessI(String sName,long nPos) throws IOException id`9,IJx  
{ TK> ~)hc}  
oSavedFile = new RandomAccessFile(sName,"rw"); 4T)`%Oo<}  
this.nPos = nPos; v,rKuvc'  
oSavedFile.seek(nPos); | z}VP-L  
} <7ag=IgDy  
9K&YHg:1  
I7f :TN  
public synchronized int write(byte[] b,int nStart,int nLen) Uul5h8F  
{ y?}<SnjP:  
int n = -1;  mSFA i  
try{ "x_G6JE4tv  
oSavedFile.write(b,nStart,nLen); VeFfkg4  
n = nLen; KUq(&H7  
} pwVGe|h%,  
catch(IOException e) pnv)D}"  
{ NZ^hp\q  
e.printStackTrace (); YB{'L +Wbw  
} 9I1`*0A  
yWH!v]S  
2'ws@U}lR  
return n; AQ"rk9Z  
} mI^S% HT  
YcSPU(  
\/ Zo*/  
} UD2 l!)rW  
$O;a~/T  
U:aaa  
/* ronZa0  
**SiteInfoBean.java @GQtyl;q  
*/ .36]>8  
package NetFox; 1l}fX}5%I;  
u@4khN: ^p  
6*tky;  
public class SiteInfoBean { OR10IS  
(gutDUO;  
d8^S~7  
private String sSiteURL; //Site's URL d&DQ8Gm ^  
private String sFilePath; //Saved File's Path ]6WP;.[  
private String sFileName; //Saved File's Name .  
private int nSplitter; //Count of Splited Downloading File 'L%)B-,n  
4"+v:t)z6{  
y(**F8>?xE  
public SiteInfoBean() Ige*tOv2  
{//nSplitter的缺省值为5 )Y=ti~?M(  
//default value of nSplitter is 5 4_ZHY?VRd  
this("","","",5); drB$q [Ak9  
} '^:q|h  
P`n"E8"ab<  
//}KWz  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;'4Kg@/  
{ `6*1mE1K&  
sSiteURL= sURL; sFRQFX0XoY  
sFilePath = sPath; kl5Y{![/&f  
sFileName = sName; H<3a yp$  
this.nSplitter = nSpiltter; 7}Jn`^!  
ENZYrWl  
#\O?|bN'q  
} ]ex2c{ G  
"A}2iI  
i uoZk5O  
public String getSSiteURL() 9 E  
{ 8ao>]5Rs3  
return sSiteURL; ^ Mq8jw(2  
} J/A UOInh  
']>/$[!  
5S%#3YHY2  
public void setSSiteURL(String value) V_H0z  
{ vsbD>`I  
sSiteURL = value; e:iqv?2t  
} +2^Mz&I@b  
@?[}\9dW  
I- WR6s=  
public String getSFilePath() x^!LA,`j  
{ FmtV[C #  
return sFilePath; E"t79dD  
} )9V8&,  
c8qwsp  
ZTi KU)  
public void setSFilePath(String value) gib;> nuBK  
{ C +S>;1  
sFilePath = value; 2~W8tv0^b2  
} _!E/ em  
d2<+Pp  
-f%J_`  
public String getSFileName() o<i\1<eI  
{ "v5jYz5M  
return sFileName; 43o!Vr/ S  
} PQ4)kVT  
C3e0d~C  
:LX (9f   
public void setSFileName(String value) &l(PWU  
{ C4t@;U=x  
sFileName = value; vo]$[Cp|4  
} 1<&nHFJ;[  
JI[9c,N  
Mp`i@pm+  
public int getNSplitter() APL #-`XC  
{ !1Z rS  
return nSplitter; +p_>fO  
} $|!@$Aj  
h<IPV'1  
1A;f[Rze  
public void setNSplitter(int nCount) Nd61ns(N  
{ JAP4Vwj%j  
nSplitter = nCount; .V\: )\<|  
} ttA0* >'  
} !ZTBiC5R  
C: <TJ  
Vh5Z'4N  
/* j+Q E~L  
**Utility.java Sv|jR r'  
*/ !d3:`l<  
package NetFox; Qwu~ {tf+'  
vHxLn/  
8d*W7>rq  
public class Utility { ,lr\XhO  
{{ /-v3n  
Jx4"~ 4  
public Utility() ''~#tK f  
{ ! )PV-[2  
)MU)'1jc,  
P`!31P#]L  
} 8:)itYE  
k&SI -jxj  
//线程睡眠 Z^SF $+UN  
public static void sleep(int nSecond) a  C<  
{ Q=Y1kcTOn  
try{ ^Y- S"Ks  
Thread.sleep(nSecond); !Au9C   
} $g+q;Y~i0  
catch(Exception e) :ZP`Y%dt'  
{ ,CA3Q.y>|  
e.printStackTrace (); _vgFcE~E@  
} j9]H~:g$d  
} <m!(eLm+B  
DQRr(r~2Kj  
//日志 |$aTJ9 Iq:  
public static void log(String sMsg) 9$oU6#U,h  
{ b Q6<R4  
System.err.println(sMsg); t (>}  
} +U];  
 (:ObxJ*  
$wx)/t<  
public static void log(int sMsg) H|i39XV  
{ "<5su5]  
System.err.println(sMsg); |'" 17c&  
} SByn u  
} HHU0Nku@ho  
R#0Z  
g8^YDrH  
/* S LSbEm  
**TestMethod.java leSR2os  
*/ 4OOH 3O  
package NetFox; bQFMg41*w7  
;)nV  
x."/+/  
public class TestMethod { 4Cl41a  
Ug1n4X3FKn  
d5O_~x f&  
public TestMethod() <B %s9Zy  
{ ///xx/weblogic60b2_win.exe ExDv7St1(k  
try{ jx7b$x]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6*]g~)7`Q~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $x'p+&n\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); D#I^;Xg0h  
fileFetch.start(); _R 6+bB$  
} 7eyVm;LQD  
catch(Exception e){e.printStackTrace ();} 71GyMtX   
&+v!mw>  
WK<:(vu.  
} ;I^+u0ga  
SL O~   
iE;D_m.>`O  
public static void main(String[] args) m\hzQ9  
{ /P>t3E2c  
new TestMethod(); :4V8Iz 71  
} SZhW)0  
} I \DH  
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