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http断点续传简单实现(java)

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/* [IL*}M!  
**SiteFileFetch.java s?w2^<P  
*/ 1xB}Ed*k  
package NetFox; [eX]x  
import java.io.*; ]vvYPRV76  
import java.net.*; ("9bV8:@B  
.AfZ5s]/F  
cFUD$mp  
public class SiteFileFetch extends Thread { [.gk{> #  
vd%g'fTy9  
nkW})LyB\  
SiteInfoBean siteInfoBean = null; //文件信息Bean $ DL}jH^S  
long[] nStartPos; //开始位置 vMTf^V  
long[] nEndPos; //结束位置 VdlT+'HF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $w0TEO!  
long nFileLength; //文件长度 X1Yw=t~a  
boolean bFirst = true; //是否第一次取文件 gP2zDI   
boolean bStop = false; //停止标志 h  d3  
File tmpFile; //文件下载的临时信息 aM}9ZurI  
DataOutputStream output; //输出到文件的输出流 V8^la'_j  
I/O3OD  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) FK _ ZE>  
public SiteFileFetch(SiteInfoBean bean) throws IOException mUBy*.  
{ 2q~ .,vpP  
siteInfoBean = bean; PG&t~4QM`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); XF!L.'zH  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e"E8BU  
if(tmpFile.exists ()) $.PRav  
{ A)f-r  
bFirst = false; 8q^}AT<C  
read_nPos(); dli(ckr  
} (` *BZ_  
else yw^Pok5.  
{ (dy(.4W\  
nStartPos = new long[bean.getNSplitter()]; Q{[@n  
nEndPos = new long[bean.getNSplitter()]; >q"dLZ  
} `i.BB jx`  
{VcRur}&Y8  
S!(3-{nC  
n' ~ ==2  
} cQ8[XNa  
9@ k8$@  
&dyQ6i$],  
public void run() vqm|D&HU  
{ vpQ&vJfR  
//获得文件长度 TeHJj`rdAU  
//分割文件 yf&g\ke  
//实例FileSplitterFetch O^L]2BVC  
//启动FileSplitterFetch线程 ;wn9 21r  
//等待子线程返回 pY31qhoZ.  
try{ `YNzcn0x  
if(bFirst) Sdu\4;(  
{ {wqT$( (<  
nFileLength = getFileSize(); bb6x} jR  
if(nFileLength == -1) bMO^}qR`  
{ gv*b`cl  
System.err.println("File Length is not known!"); k@4N7}  
} }y(t')=9  
else if(nFileLength == -2) U=Ps#  
{ M\]lNQA  
System.err.println("File is not access!"); i|eX X)$  
} `"5U b,~  
else ;UQGi}?CD  
{ %_(vSpk  
for(int i=0;i<nStartPos.length;i++) B)0/kY7c  
{ [l}H:%O,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Hjm> I'9  
} zp}7p~#k^  
for(int i=0;i<nEndPos.length-1;i++) p<5]QV7st  
{ Q((&Q?Vi  
nEndPos = nStartPos[i+1]; sxNf"C=-.  
} [D"6&  
nEndPos[nEndPos.length-1] = nFileLength; )+_Vx}O:}  
} htBA.eQ  
} dyQ7@K.E  
)lG}B U.  
UG2+Y']  
//启动子线程 yE:y[k0E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |E8sw a  
for(int i=0;i<nStartPos.length;i++) y=Y k$:-y  
{ Q]WBH_j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]A5F}wV4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]LvP)0=  
nStartPos,nEndPos,i); =pL$*`]?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Nq8ON!<<  
fileSplitterFetch.start(); (TZK~+]@sb  
} "qmSwdM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *C_A(n5"V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); q/s-".%P  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", K=gg<E<  
nEndPos = " + nFileLength); #C9f?fnM  
// fileSplitterFetch[nPos.length-1].start(); f_~T  
;hT3N UCA  
,/f\  
//等待子线程结束 kWr1>})'  
//int count = 0; &~:EmLgv  
//是否结束while循环 Ip t;NlR  
boolean breakWhile = false; j.=:S;  
?8~l+m6s$  
9UM)"I&k  
while(!bStop) H:.~! r  
{ v "l).G?  
write_nPos(); u?,>yf.;s  
Utility.sleep(500); X!KX4H  
breakWhile = true; HPtMp#`T  
q{w|`vIb  
Ed=/w6<  
for(int i=0;i<nStartPos.length;i++) +hRy{Ps/  
{  2E*=EjGV  
if(!fileSplitterFetch.bDownOver) 8m+~HSIR  
{ +SFFwjI  
breakWhile = false; k4{!h?h  
break; Ej(BE@6>s  
} b|i4me@  
} ~XR ('}5D  
if(breakWhile) |lNp0b  
break; |4+'YgO  
Ag8/%a~(  
 Xu-~j!  
//count++;  [N,+mX  
//if(count>4) 7$*E0  
// siteStop(); Tvv>9gS  
} ]]|#+$ ~  
SdnnXEB7  
)Jt. Z^J<  
System.err.println("文件下载结束!"); , z\Qd07u  
} ]L3U2H`7  
catch(Exception e){e.printStackTrace ();} WJ8i=MO67  
} JD *HG]  
^Gk)aX  
<X*oW".  
//获得文件长度 & AK\Pw)  
public long getFileSize() ]!ai?z%cK#  
{ {V7mpVTX.  
int nFileLength = -1; (wu'FFJp#  
try{ Kw-<o!~  
URL url = new URL(siteInfoBean.getSSiteURL()); AZ.QQ*GZ#y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d9 [j4q_  
httpConnection.setRequestProperty("User-Agent","NetFox"); YP,,vcut  
a;[\nCK  
EjfQF C  
int responseCode=httpConnection.getResponseCode(); EV6R[2kl  
if(responseCode>=400) B EwaQvQ!  
{ 7;Ze>"W>  
processErrorCode(responseCode); +3o vO$g  
return -2; //-2 represent access is error 2/3yW.C  
} 1uw1(iL+  
.=:f]fs  
A;8kC}  
String sHeader; jU-LT8y:  
3I 0pHP5  
+.Vh<:?  
for(int i=1;;i++) <y7{bk~i  
{ db 99S   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >_j(uw?u  
//Utility.log(in.readLine()); x<I[?GT=  
sHeader=httpConnection.getHeaderFieldKey(i); 3$"V,_TBZ  
if(sHeader!=null) G$,s.MSf  
{ ZV{C9S&  
if(sHeader.equals("Content-Length")) {XU!p: x  
{ l2;$qNAo  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); b@J"b(  
break; N[eL Qe]q  
} k -G9'c~  
} /T6bc^nOW  
else *Xnf}Ozx  
break; ?=lb@U  
} U-DQ?OtmC@  
} vyS>3(NZ  
catch(IOException e){e.printStackTrace ();} = cRmaD  
catch(Exception e){e.printStackTrace ();} 2Pb+/1*ix  
d5-Q}D,P  
PxYK)n9&  
Utility.log(nFileLength); h GA2.{  
rn . qs  
T[4xt,[a  
return nFileLength; @7}XBg[pI  
} 0d2RB^"i  
Rir0^XqG  
l^I? @{W  
//保存下载信息(文件指针位置) >V8!OaY5n  
private void write_nPos() |6^a[x3/U  
{ <yl@!-'J7  
try{ oL9<Fi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $-/-%=  
output.writeInt(nStartPos.length); c) Eu(j\#  
for(int i=0;i<nStartPos.length;i++) 8(j]=n6 r  
{ XOX$uLm  
// output.writeLong(nPos); 4x ?NCD=k  
output.writeLong(fileSplitterFetch.nStartPos); ], Bafz)4  
output.writeLong(fileSplitterFetch.nEndPos); 2{RRaUoRb  
} t{UVX%b  
output.close(); uKzx >\}?1  
} )xf(4  
catch(IOException e){e.printStackTrace ();} %UdE2D'bC  
catch(Exception e){e.printStackTrace ();} x#E M)Thq  
} ;|K }  
i;pg9Vw  
'bRf>=  
//读取保存的下载信息(文件指针位置) G1it 3^*$  
private void read_nPos() iJdJP)!tz6  
{ 1PxRj  
try{ kKRu]0J~[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); . AA# G  
int nCount = input.readInt(); < e3] pM  
nStartPos = new long[nCount]; L [PqEN\i  
nEndPos = new long[nCount]; )'jGf;du  
for(int i=0;i<nStartPos.length;i++) B Hp>(7,  
{ ] K&ca  
nStartPos = input.readLong(); H.M: cD:  
nEndPos = input.readLong(); `yq) y>_  
} pS-o*!\C.  
input.close(); &LI q?  
} n<|8Onw  
catch(IOException e){e.printStackTrace ();} gna!Q  
catch(Exception e){e.printStackTrace ();} q=e;P;u  
} <zY#qFQ2  
V|A.M-XLv4  
8m H6?,@6  
private void processErrorCode(int nErrorCode) +Y*4/w[   
{ = mQY%l  
System.err.println("Error Code : " + nErrorCode); aNM*=y`  
} Q0`@=5?-  
}+lK'6  
fFVQu\  
//停止文件下载 hQ>$ "0K  
public void siteStop() {{gd}g  
{ k6DJ(.n'%a  
bStop = true; IM6n\EZ^  
for(int i=0;i<nStartPos.length;i++) +z9BWo!{I  
fileSplitterFetch.splitterStop(); Q(x=;wf5r  
Jv 5l   
p]X+#I<  
} /(||9\;  
} c='W{47  
//负责部分文件的抓取 $Vp&7OC]  
**FileSplitterFetch.java ^{J^oZ'%~  
*/ 44n41.Q]  
package NetFox; [ s/j?/9  
-mO<(wfV>  
~eTp( XG  
import java.io.*; T__@hfT  
import java.net.*; 1Z_]Ge<a  
PRYm1Y  
k^JgCC+  
public class FileSplitterFetch extends Thread { r#j3O}(n  
h`Ej>O7m  
=|O]X|y-lZ  
String sURL; //File URL >yenuqIKQv  
long nStartPos; //File Snippet Start Position b* n#XTV  
long nEndPos; //File Snippet End Position H9_>a-> )~  
int nThreadID; //Thread's ID L kafB2y  
boolean bDownOver = false; //Downing is over Eb5>c/(  
boolean bStop = false; //Stop identical ?st}rJ_  
FileAccessI fileAccessI = null; //File Access interface ?3LV$S)U  
uFuH/(}K[  
Pvv7|AV   
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _;BNWH  
{ ^eoW+OxH  
this.sURL = sURL; R/B/|x  
this.nStartPos = nStart; }#g &l*P  
this.nEndPos = nEnd; V/\`:  
nThreadID = id; l YdATM(h  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \2f?)id~  
} taVK&ohWx  
 OvC@E]/+  
1*#hIuoj'  
public void run() mWoN\Rwj  
{ &f A1kG%  
while(nStartPos < nEndPos && !bStop) lZ"C~B}9:I  
{ '&|%^9O/"  
$^e_4]k  
p&xj7qwp@F  
try{ SRHD"r^@  
URL url = new URL(sURL); f/kYm\Zc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #~rQ\A!4  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,o `tRh<  
String sProperty = "bytes="+nStartPos+"-"; ,rY}IwM w  
httpConnection.setRequestProperty("RANGE",sProperty); HA$7Q~{N-t  
Utility.log(sProperty); _=[pW2p  
E^w0X,0XlE  
P$O@G$n  
InputStream input = httpConnection.getInputStream(); =L"I[  
//logResponseHead(httpConnection); e=tM=i"  
Z0~,cO8~  
~T._ v;IT  
byte[] b = new byte[1024]; iF:NDqc  
int nRead; 'L1yFv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ncsk(`lo  
{ m,4'@jg0  
nStartPos += fileAccessI.write(b,0,nRead); k9y/.Mu  
//if(nThreadID == 1) 0!c/4^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DM,;W`|6%  
} *rm[\  
rd(-2,$4  
\u/=?b  
Utility.log("Thread " + nThreadID + " is over!"); UBuG12U4Y  
bDownOver = true; <qoPBm])  
//nPos = fileAccessI.write (b,0,nRead); c!$~_?]  
} Tz(Dhb,  
catch(Exception e){e.printStackTrace ();} {v3@g[:|  
} MzW!iG  
} ~vZ1.y4  
TYxi &;w  
Pl|*+g  
//打印回应的头信息 cnDBT3$~Z  
public void logResponseHead(HttpURLConnection con) naY#`xig  
{ nrTCq~LO(  
for(int i=1;;i++) 2Y}A9Veb  
{ esv<b>`R  
String header=con.getHeaderFieldKey(i); qm=9!jqC;  
if(header!=null) ,+5 !1>\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .KYDYdoS'  
Utility.log(header+" : "+con.getHeaderField(header)); ^'vWv C  
else ,y7X>M2  
break; (WGEX(|  
} H[/^&1P  
} 2ZxZ2?.uJ  
DY87NS*HF  
B an" H~  
public void splitterStop() NA$ODK -  
{ <U /r U9O  
bStop = true; tgrZs8?  
} !6+V  
/jU4mPb;\D  
- :x6X$=  
} Pv$O=N6-  
;4vx+>-  
?l 0WuU  
/* Nu; 9  
**FileAccess.java cl'qw##  
*//文件访问(定位,写) 0te[i*G  
package NetFox; $O9#4A;  
import java.io.*; M[Jy?b)  
!;U}ax;AF  
< $rXQ  
public class FileAccessI implements Serializable{ J\ ?  
LC/%AbM  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C:}"?tri  
RandomAccessFile oSavedFile; .18MMzdN  
long nPos; ];Bk|xJ/>  
Or()AzwE@  
kPp7;U2A  
public FileAccessI() throws IOException 6)3pnhG9  
{ |=Pw -uk  
this("",0); ^+dL7g?+  
} eG5xJA^  
KlRIJOS  
yu'@gg(  
public FileAccessI(String sName,long nPos) throws IOException ?CuwA-j  
{ MJ@PAwv"  
oSavedFile = new RandomAccessFile(sName,"rw"); dMH}%f5;1  
this.nPos = nPos; S? (/~Vb%  
oSavedFile.seek(nPos); H[iR8<rhQ  
} KQrG|<J  
 !*-|s}e  
J po(O>\P  
public synchronized int write(byte[] b,int nStart,int nLen) NFb<fD[C  
{ %t,Fxj4F  
int n = -1; AhSN'gWpbF  
try{ &;%LTF@I,  
oSavedFile.write(b,nStart,nLen); E"Y[k8-:2/  
n = nLen; Ivc/g,  
} V)Y#m/$`  
catch(IOException e) h!]=)7x;  
{ i}LVBx"K(  
e.printStackTrace (); $%3%&+z$I  
} ,y*|f0&"~  
$[*<e~?  
DqBiBH[%h  
return n; mp>Ne6\Tu  
} ,A!0:+  
p+1kU1F0  
Sa$-Yf  
} Eg#WR&Uq"  
ksli-Px  
^/$bd4,z  
/* kt hy9<!$  
**SiteInfoBean.java m2PI^?|e  
*/ `9p;LZC1K  
package NetFox; eq$.np  
|Skhx9};  
rTtxmw0  
public class SiteInfoBean { B["C~aF  
2G BE=T  
X?OH//co  
private String sSiteURL; //Site's URL .0'FW!;FV  
private String sFilePath; //Saved File's Path .L}k-8  
private String sFileName; //Saved File's Name 5g;i{T/6~x  
private int nSplitter; //Count of Splited Downloading File #qdfr3  
CR'1,  
c\(CbC  
public SiteInfoBean() &X OFc.u  
{//nSplitter的缺省值为5 j.7BoV  
//default value of nSplitter is 5 VPXUy=W  
this("","","",5); X< p KAO\  
} !"QvV6Lq\  
Xg1QF^  
o",J{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _ "H&  
{ y^hCO:`l3  
sSiteURL= sURL; p`06%"#  
sFilePath = sPath; c R6:AGr  
sFileName = sName; 1gDsL  
this.nSplitter = nSpiltter; +I r  
C7 T}:V](q  
zqa7!ky  
} FWDAG$K@0  
v<t r1cUT  
J'Y;j^  
public String getSSiteURL() S;I}:F#5  
{ [,/~*L;7  
return sSiteURL; ^s?=$&8f![  
} )TzQ8YpO}  
,\=,,1_  
n]fMl:77  
public void setSSiteURL(String value) {E$smX  
{ 6k*,Yei  
sSiteURL = value; R*r;`x  
} @pO2A6 Ks  
wOs t).  
I7e.p m  
public String getSFilePath() D $3Mg  
{ 6$A>%Jtwe  
return sFilePath; Dt=@OZW  
} KetNFwbUf  
:2(U3~3:  
8zzY;3^h;  
public void setSFilePath(String value) `(o:;<&3  
{ }GL@?kAGR5  
sFilePath = value; zX}t1:nc  
} B'8/`0^n5  
5l4YYwd>v  
G#nZ%qQ:I  
public String getSFileName() 5V@c~1\  
{ 'j(F=9)  
return sFileName; yttaZhK^u  
} kBg8:bo~  
)uu1AbT +e  
P:&X1MC  
public void setSFileName(String value) = 4 wf  
{ ?Es(pwJB  
sFileName = value; YML]pNB  
} bfX yuv  
u4vyj#V  
uJ T^=Y  
public int getNSplitter() iqr/MB,W  
{ omzG/)M:O  
return nSplitter; Z|$M 9E  
} x ?24oO  
}ej>uZVe<  
&hu>yH>j  
public void setNSplitter(int nCount) ;{89*e*)  
{ F_F02:t  
nSplitter = nCount; ! 8*l U2  
} wGg_ vAn  
} FS^~e-A  
Ra/Pk G-7  
VDTt}J8  
/* 7m:ZG  
**Utility.java cB=ExD.Q  
*/ Lz{z~xNHW.  
package NetFox; <NXJ&xs-+  
{e p(_1  
Oe ~g[I;  
public class Utility { D$Eq~VQ  
yc+pNC)ue_  
~sT1J|  
public Utility() AW8*bq1  
{ B;e (5y-  
03H0(ku=  
y4)iL?!J~  
} M>[e1y>7  
Hg5 :>?Lw@  
//线程睡眠 +h08uo5c  
public static void sleep(int nSecond) nM| Cv  
{ E.N  
try{ #f<3[BLx  
Thread.sleep(nSecond); S`8Iu[Ma  
} Z5|BwM  
catch(Exception e) );;UA6CD  
{ .F},Z[a&  
e.printStackTrace (); T/]f5/  
} Z7XFG&@6  
} gVNoC-n)  
F.),|t$\  
//日志 KX J7\}  
public static void log(String sMsg) 2F :8=_sA  
{ gCq'#G\Z  
System.err.println(sMsg); T>68 ,; p  
} ,&.$r/x|?  
>#VNA^+t  
^B:;uyG]M  
public static void log(int sMsg) VwOcWKD  
{ JED\"(d(  
System.err.println(sMsg); < 1[K1'7h  
} \@[,UZ  
} BU#3fPl  
e|N~tUVrrN  
>L ')0<!&  
/* +pRNrg?k  
**TestMethod.java GZ^Qt*5 {  
*/ YPW UncV  
package NetFox; *:"@  
mv 7W03  
dXfLN<nD>U  
public class TestMethod { &~=r .T  
Zm0'p!  
5] LfJh+"n  
public TestMethod() ,Qs%bq{t  
{ ///xx/weblogic60b2_win.exe LcZ|A;it  
try{ " T9UedZ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !2h ZtX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6?'7`p  
SiteFileFetch fileFetch = new SiteFileFetch(bean); t{s*,X\b  
fileFetch.start(); k!Q{u2  
} q=}1ud}1  
catch(Exception e){e.printStackTrace ();} DD2K>1A1  
.+,U9e:%  
>n^780S|  
} T*nP-b  
&r\8VEZq"  
|Ve,Y  
public static void main(String[] args) 5vg="@O K  
{ (zh[1[a  
new TestMethod(); tva=DS  
} oC-v>&bW  
} yzv"sd[8N  
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