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http断点续传简单实现(java)

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/* !- QB>`7$  
**SiteFileFetch.java b3%a4Gg&  
*/ <'sm($.2  
package NetFox; W  wj+\  
import java.io.*; k$J!,!q  
import java.net.*; /=9dX; #  
KV&6v`K/N  
F 8sOc&L  
public class SiteFileFetch extends Thread { $J)`Ru6.  
!qlk-0&`  
M3]eqxLC  
SiteInfoBean siteInfoBean = null; //文件信息Bean bVN?7D(  
long[] nStartPos; //开始位置 _]Ob)RUVH  
long[] nEndPos; //结束位置 qyKR]%yzi  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =+DhLH}8  
long nFileLength; //文件长度 P2s\f;Dwr  
boolean bFirst = true; //是否第一次取文件 mA,{E-T  
boolean bStop = false; //停止标志 f8r7 SFwUv  
File tmpFile; //文件下载的临时信息 +/mCYI  
DataOutputStream output; //输出到文件的输出流 f!5w+6(  
@RuMo"js  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 3%o}3.P,:@  
public SiteFileFetch(SiteInfoBean bean) throws IOException Lp|n)29+du  
{ y,n.(?!*  
siteInfoBean = bean; xpuTh"ED  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eA?|X|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); T7/DH  
if(tmpFile.exists ()) Zj ^e8u=T  
{ \j wxW6>  
bFirst = false; p*YV*Arv  
read_nPos(); 7MJ\*+T|03  
} Ujvm|ml  
else :cXN Fu\C  
{ MuzQ z.C  
nStartPos = new long[bean.getNSplitter()]; 7AGUi+!ICl  
nEndPos = new long[bean.getNSplitter()]; wEI? 9  
} bv hV  
!e |Bi{  
|<oqT+?i  
x.|sCqx  
} c0&! S-4M  
d >zC[]1  
""N~##)8  
public void run() 0/7.RpX,.  
{ u` (yT<>H  
//获得文件长度 $*_79F2zN  
//分割文件 Ks(l :oUB  
//实例FileSplitterFetch gy|o#&e]%  
//启动FileSplitterFetch线程 s)-bOZi  
//等待子线程返回 ".( G,TW  
try{ &><b/,]  
if(bFirst) upeioC q  
{ .s41Tc5u  
nFileLength = getFileSize(); 1LvR,V<  
if(nFileLength == -1) Rd]<591  
{ NzM,0q  
System.err.println("File Length is not known!"); L|-|DOgw  
} 3X',L*f  
else if(nFileLength == -2) Uy)pEEu  
{ (47la$CR  
System.err.println("File is not access!"); jMS>B)'TO  
} ('dbMH\O  
else Tl]yl$  
{ ,->5 sJ{U  
for(int i=0;i<nStartPos.length;i++) #NL'r99D/o  
{ G6x'Myg I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); itiSZL,  
} |_+l D|'  
for(int i=0;i<nEndPos.length-1;i++) :1gpbfW  
{ #a tL2(wJ  
nEndPos = nStartPos[i+1]; )_o^d>$da  
} akCCpnX_d  
nEndPos[nEndPos.length-1] = nFileLength; WI&}94w  
} .V UnOdI  
} eHd7fhW5  
-GB,g=Dk  
ty%,T.@e  
//启动子线程 >+!Ef  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h>!9N dzG  
for(int i=0;i<nStartPos.length;i++) UYW'pV  
{ e$`hRZ%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WW^+X~Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `P:[.hRu  
nStartPos,nEndPos,i); H<?s[MH[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -2 8bJ,  
fileSplitterFetch.start(); TK~KM  
} Co=Bq{GY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {L.uLr_?e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _nX8f &  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :B7U),T  
nEndPos = " + nFileLength); #!#s7^%K&  
// fileSplitterFetch[nPos.length-1].start(); @+y,E-YTdV  
m] -cRf)9  
3r,Kt&2$  
//等待子线程结束 V 7ZGT  
//int count = 0; JZ:yPvJ  
//是否结束while循环 GWWaH+F[h  
boolean breakWhile = false; H(M{hfa|  
m"'`$/_  
+~y>22Zfg  
while(!bStop) qss )5a/x.  
{ $ye>;Ek  
write_nPos(); x_C0=Q|K3  
Utility.sleep(500); d:#tN4y7(  
breakWhile = true; cJTwgm?  
 tL<.B  
w $`w  
for(int i=0;i<nStartPos.length;i++) ^7=7V0>,:  
{ '^$+G0jv  
if(!fileSplitterFetch.bDownOver) @^ m0>H  
{ fd>&RbUp  
breakWhile = false; DrxQ(yo}  
break; Q#K10*-O6  
} @A*>lUo  
} '4Qsl~[Eh  
if(breakWhile) AR$SQ_4  
break; Z`ww[Tbv~  
k{UeY[,jb  
b&LAk-}[  
//count++; O(D2F$VlL  
//if(count>4) BIe:7cR%  
// siteStop(); d/~g3n>|  
} u3tT=5.D  
U)aftH *Pk  
.|s,':hA  
System.err.println("文件下载结束!");  vP? T  
} ~gNFcJuy  
catch(Exception e){e.printStackTrace ();} {0-rnSjC  
} x)eoz2E1  
MPw?HpM  
S3E5^n\\  
//获得文件长度 GCfVH?Vx  
public long getFileSize() R-1MD  
{ mF jM6pmo  
int nFileLength = -1; AS;qJ)JfzQ  
try{ @' ;.$  
URL url = new URL(siteInfoBean.getSSiteURL()); Aq3\Q>klH)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &Vgpv#&Cfx  
httpConnection.setRequestProperty("User-Agent","NetFox"); g0B%3v  
G|8>Q3D  
QgQ$>  
int responseCode=httpConnection.getResponseCode(); Np ru  
if(responseCode>=400) > '. : Acn  
{ v7`{6Pf_$  
processErrorCode(responseCode); 4i+%~X@p  
return -2; //-2 represent access is error N>]J$[j  
} #k`gm)|  
8?YeaMIBB  
q(~|roKA(  
String sHeader;  jIH^  
uI%7jA~@  
BHZhdm@),  
for(int i=1;;i++) +"=ydF.9  
{ lCl5#L9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V{A`?Jl6{  
//Utility.log(in.readLine()); EUQtl_h/H  
sHeader=httpConnection.getHeaderFieldKey(i); d)acWF\  
if(sHeader!=null) lmD [Cn  
{ & 0WQF  
if(sHeader.equals("Content-Length")) V'MY+#  
{ yBIX<P)vE'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); yTZ o4c "  
break; cF8X  
} Q[K)Yd  
} K :~tZ  
else mZPvG  
break; j0a=v}j3  
} a }*i [  
} rPGj+wL5-  
catch(IOException e){e.printStackTrace ();} /@\R  
catch(Exception e){e.printStackTrace ();} BzO,(bd!PI  
RwOOe7mv  
SPt/$uYJ  
Utility.log(nFileLength); |g!d[ct]  
N2duhI6  
u#Jr_ze  
return nFileLength; 32%Fdz1S  
} *h3iAcM8  
K5 BL4N  
#d-zH:uq  
//保存下载信息(文件指针位置) eNVuw:Q+  
private void write_nPos() u'>94Gm}  
{ A>2_I)  
try{ NMf#0Nz-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); g=@d!]Z~[  
output.writeInt(nStartPos.length); AovBKB $  
for(int i=0;i<nStartPos.length;i++) zp<B,Ls  
{ 1 ptyiy  
// output.writeLong(nPos); [0]A-#J  
output.writeLong(fileSplitterFetch.nStartPos); ZILJXX4  
output.writeLong(fileSplitterFetch.nEndPos); 5\#I4\  
} ~QxW^DGa7]  
output.close(); B%MdJ D>  
} pq&[cA_w  
catch(IOException e){e.printStackTrace ();} K%x]:|,>M  
catch(Exception e){e.printStackTrace ();} IM/xBP  
} x-X~'p'f  
BI%XF 9{  
vB{i w}Hi!  
//读取保存的下载信息(文件指针位置) NlKVl~_ C  
private void read_nPos() )OxcCV?5Z  
{ rVl 8?u y  
try{ fi%i 2Wy  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3Ke6lV)uq  
int nCount = input.readInt(); m|{^T/kIbQ  
nStartPos = new long[nCount]; #5z0~Mg-X  
nEndPos = new long[nCount]; GJr mK  
for(int i=0;i<nStartPos.length;i++) L+<h 5>6  
{ 2Ki_d  
nStartPos = input.readLong(); {5<fvMO!6  
nEndPos = input.readLong(); >V27#L2:J  
} bp=r]nO  
input.close(); 4R\jZ@D  
} jHn7H)F8  
catch(IOException e){e.printStackTrace ();} %]DA4W  
catch(Exception e){e.printStackTrace ();} 83t/ \x,Q  
} c3g`k"3*`  
?Y,^Moc:  
'xx M0Kn`  
private void processErrorCode(int nErrorCode) Z_m<x!  
{ YI,t{Wy  
System.err.println("Error Code : " + nErrorCode); 62zu;p9m  
} m} s.a.x  
Rk3 bZvj3  
AguE)I&m  
//停止文件下载 /[\g8U{5B}  
public void siteStop() 1(IZ,*i  
{ P@vUQ  
bStop = true; L-D4>+  
for(int i=0;i<nStartPos.length;i++) ob;|%_  
fileSplitterFetch.splitterStop(); z06,$OYz  
/YHO"4Z  
~nfOV*  
} w3);ZQ|  
} $m2#oI 'D  
//负责部分文件的抓取 _ s3d$C?B  
**FileSplitterFetch.java b&&l   
*/ 72Y 6gcg  
package NetFox; NGl 8*Af   
3,{eH6,O7M  
 ,S=[#  
import java.io.*; rD SYR\cg  
import java.net.*; 0r1GGEW`s  
9 $$uk'}w!  
\+O.vRc"M  
public class FileSplitterFetch extends Thread { Z6i~Dy3  
PD.$a-t  
0ck3II  
String sURL; //File URL rVNx 2  
long nStartPos; //File Snippet Start Position gI;"PkN  
long nEndPos; //File Snippet End Position $a*7Q~4  
int nThreadID; //Thread's ID  7N[".V]c  
boolean bDownOver = false; //Downing is over NOXP}M  
boolean bStop = false; //Stop identical lsOv#X-b E  
FileAccessI fileAccessI = null; //File Access interface PD0&ep1h7G  
bN zb#P#hP  
D~ Y6%9  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException n*wQgC'vw  
{ ra T9  
this.sURL = sURL; m]>zdP+  
this.nStartPos = nStart; e! *] y&W  
this.nEndPos = nEnd; QTi@yT:  
nThreadID = id; 9Sxr9FLW~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6Qt(Yu*s  
} [_(J8~ va  
@NRN#~S,_]  
$5JeN{B  
public void run() |du%c`wl  
{ 018SFle  
while(nStartPos < nEndPos && !bStop) WT<}3(S'?  
{ m.m6.  
&`l\Q\_[@  
c.IUqin  
try{ 6-_g1vq  
URL url = new URL(sURL); fc*>ky.v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5+M,X kg  
httpConnection.setRequestProperty("User-Agent","NetFox"); `5?0yXK  
String sProperty = "bytes="+nStartPos+"-"; `z(o01y  
httpConnection.setRequestProperty("RANGE",sProperty); CsA(oX  
Utility.log(sProperty); vu*e*b$}  
2lpPN[~d  
))|d~m  
InputStream input = httpConnection.getInputStream(); T:@6(_Z  
//logResponseHead(httpConnection); >^jBE''  
t[`LG)  
Gg'!(]v  
byte[] b = new byte[1024]; .T9$O]:o  
int nRead; m1pA]}Y/5o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @-dGZ 5  
{ 9m)$^U>oz  
nStartPos += fileAccessI.write(b,0,nRead); Hp=BnN  
//if(nThreadID == 1) ay7\Ae]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *gwlW/%Fz  
} }S u j=oFp  
8j#S+=l>  
1DB{"8ov  
Utility.log("Thread " + nThreadID + " is over!"); V ,p~,rC  
bDownOver = true; ^Qx?)(@  
//nPos = fileAccessI.write (b,0,nRead); U3a2wK  
} q8d](MaX  
catch(Exception e){e.printStackTrace ();} Ow/,pC >V  
} +fXwbZ?p  
} f-|?He4O]  
KBB)xez8  
b_~XTWP$l  
//打印回应的头信息 `&D#P%  
public void logResponseHead(HttpURLConnection con) RBrb7D{  
{ =Q(J!f  
for(int i=1;;i++) 940:NOgm  
{ DH?n~qKpC  
String header=con.getHeaderFieldKey(i); _gqqPny4$  
if(header!=null) c1k[)O~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); p*Q-o  
Utility.log(header+" : "+con.getHeaderField(header)); (a_bU5)  
else D0jV}oz  
break; $\NqD:fgb  
} e' l9  
}  7(+4^  
'Eur[~k  
9-T<gYl  
public void splitterStop() >XgJo7u  
{ e n~m)r3&  
bStop = true; Sxq@W8W  
} ck{S  
}?,?2U,8:  
Q^f{H.  
} 4}m9,  
$~b6H]"9  
i`gM> q&  
/* <4Gy~?  
**FileAccess.java Nf )YG!  
*//文件访问(定位,写) l%EvXdZuOy  
package NetFox; vWoppt  
import java.io.*; @. -S(MNR  
X3}eq|r9  
L=#NUNiXr  
public class FileAccessI implements Serializable{ v'S]g^  
&K0b3AWc  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 lk 1\|Q I  
RandomAccessFile oSavedFile; 53:~a  
long nPos; <8b1OdA  
(U&  
U)8yd,qG[%  
public FileAccessI() throws IOException .m]}Ba}J$  
{ pZ>yBY?R8>  
this("",0); [o<hQ`&  
} VH]}{i"`  
yIKpyyC9H  
_!o8s%9be  
public FileAccessI(String sName,long nPos) throws IOException $!*>5".A  
{ /3aW 0/^o  
oSavedFile = new RandomAccessFile(sName,"rw"); @KL&vm(F$  
this.nPos = nPos; F^gTID  
oSavedFile.seek(nPos); BjfVNF;hk:  
} I/njyV)H  
u"qVT9C$=  
+ kMj|()>\  
public synchronized int write(byte[] b,int nStart,int nLen) :u,.(INB  
{ D:Q#%wJ  
int n = -1; 8Ij<t{Lps  
try{ QZ&(e2z  
oSavedFile.write(b,nStart,nLen); [cnu K  
n = nLen; o>8~rtl  
} rByth,|  
catch(IOException e) vIJ5iLF  
{ JhFn"(O  
e.printStackTrace (); -Rw3[4>@O"  
} '* y(F*7+  
G~1;_'  
!-OZ/^l|O`  
return n; lq:q0>vyI  
} jM$bWtq2  
qt@/  
+4%~.,<_to  
} L-w3A:jk  
!s-A`} s+  
{KHI(*r;  
/* M3-lL;!n  
**SiteInfoBean.java ,A{Bx`o?  
*/ DKt98;  
package NetFox; C<J*C0vQO  
8S#$'2sT  
X "7CN Td  
public class SiteInfoBean { B`-uZ9k   
Sn*s@RE\s  
q?7''xk7  
private String sSiteURL; //Site's URL cIwX sx  
private String sFilePath; //Saved File's Path w317]-n  
private String sFileName; //Saved File's Name rQ* w3F?:  
private int nSplitter; //Count of Splited Downloading File FXBmatBck  
"v:k5a(  
(O J/u)W^  
public SiteInfoBean() O6Py  
{//nSplitter的缺省值为5 5&s6(?,Eu  
//default value of nSplitter is 5 @ 3=pFYW)  
this("","","",5); F[}#7}xjA  
} `$ f`55e  
"]=OR>  
uNn1qV  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :o^ioX.J  
{ X&zGgP/  
sSiteURL= sURL; +zMhA p  
sFilePath = sPath; 8~O#@hB~3  
sFileName = sName; E'\gd7t ;  
this.nSplitter = nSpiltter; w0g@ <( 3  
@]n8*n  
GG>53} 7{  
} ^)9/Wz _x  
h/tCve3Z  
 G06;x   
public String getSSiteURL() F\N0<o  
{ 7#C$}1XJ1  
return sSiteURL; \L(jNN0_R  
} o?}dHTk7  
t, %m-dU  
c-hc.i}!  
public void setSSiteURL(String value) 8)8~c@  
{ =Lkn   
sSiteURL = value; MPUyu(-%{  
} enPtW  
-E\G3/*51  
qe&|6M!  
public String getSFilePath() 4C?{p%3c  
{ PJZ;wqTD_  
return sFilePath; l\ dPfJ  
} %BC%fVdP  
E?+~S M1~  
PWS8Dpb  
public void setSFilePath(String value) H'3 pHb  
{ S=P}Jpq?Y;  
sFilePath = value; z+.G>0M  
} VL*5  
Jy:*GW6  
%6(\Ki6I  
public String getSFileName() =k<b* 8  
{ K7 C <}y  
return sFileName; k+{~#@  
} -I{op wd  
JYNn zgd  
Y&bYaq  
public void setSFileName(String value) gWHY7rv  
{ =T3{!\tH  
sFileName = value; iWeUsS%zpV  
} 5)f 'wVe  
LNJKf6:  
huv|l6   
public int getNSplitter() a"P & 9c  
{  Fw[1Aa#  
return nSplitter; hvTc( 0;mB  
} ,9G'1%z,  
xytWE:=  
H9jlp.F  
public void setNSplitter(int nCount) {G=>WAXo  
{ 'KmM %tN  
nSplitter = nCount; }2LG9B%  
} fV4eGIR&  
} P\ P=1NM  
=?Ry,^=b  
=55)|$hgD  
/* ])y)]H#{  
**Utility.java ^) s6`:  
*/ vrmMEWPV  
package NetFox; gAvNm[=wD2  
P}AwE,&Q  
JGq9RB]D$  
public class Utility { @8J*vY =e  
|goBIp[  
Ow?~+) 4  
public Utility() a?Fz&BE  
{ 1y[~xxgE  
R|Bi%q|4P  
Z .`+IN(>E  
} Yw=@*CK'  
o&q:b9T  
//线程睡眠 MA tF,  
public static void sleep(int nSecond) wIRU!lIF9  
{ dW/(#KP/+  
try{ ?_{{iil  
Thread.sleep(nSecond); TQt[he$O  
} d^?e*USh  
catch(Exception e) |o eg'T  
{ UBv#z&@[  
e.printStackTrace (); H '5zl^8I  
} -"yma_  
} -GL.8" c[  
b6e 2a/x  
//日志 HHyN\  
public static void log(String sMsg) <AVWT+,  
{ }6u}?>S  
System.err.println(sMsg); [EPRBK`=  
} 3J4OkwqD  
uAYDX<Ja9  
0 Q>  
public static void log(int sMsg) lnl>!z  
{ 8}oe))b  
System.err.println(sMsg); -{L 7%j|R  
} r8y,$Mv<)0  
} p&(z'd  
mtFC H  
meB9 :w[m  
/* %j2:W\g:  
**TestMethod.java }cW8B"_"  
*/ hHEn  
package NetFox; \o,et9zDJ3  
aAu%QRq  
(8S+-k?  
public class TestMethod { 4nd)*0{ f  
\ Ho VS  
N}z]OvnZH  
public TestMethod() N^`S'FVA  
{ ///xx/weblogic60b2_win.exe 6a]Qg99\  
try{ j*VYUM@y1\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IL&R&8'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Ey&A\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); gv jy'Rm  
fileFetch.start(); iF##3H$c  
} =v! 8i  
catch(Exception e){e.printStackTrace ();} '&AeOn  
V-%jSe<  
o9D#d\G  
} bA"*^"^  
7'.6/U  
#)DDQ?D  
public static void main(String[] args) A9HgABhax  
{ (ia+N/$u  
new TestMethod(); eZpi+BRS6  
} 0*OK]`9  
} coXm*X>z  
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