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http断点续传简单实现(java)

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/*  8q!]y6  
**SiteFileFetch.java +GN(Ug'R  
*/ *OsQ}onv  
package NetFox; _6hQ %hv8  
import java.io.*; G j?t_Zln  
import java.net.*; exUFS5d  
|aS.a&vwR  
b. '-?Nn  
public class SiteFileFetch extends Thread { P3=G1=47U  
MJO-q $)c  
ksUcx4;a@F  
SiteInfoBean siteInfoBean = null; //文件信息Bean -d/ =5yxL  
long[] nStartPos; //开始位置 d&Zpkbh"  
long[] nEndPos; //结束位置 yx[/|nZDC4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  7xlkZF  
long nFileLength; //文件长度 Mb}QD~=M  
boolean bFirst = true; //是否第一次取文件 8kIksy  
boolean bStop = false; //停止标志 1R%.p7@5QU  
File tmpFile; //文件下载的临时信息 Pmx -8w  
DataOutputStream output; //输出到文件的输出流 )2o?#8J  
O 8r|8]o  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) pah'>dAL  
public SiteFileFetch(SiteInfoBean bean) throws IOException t!l&iVWs  
{ ^[`%&uj!g  
siteInfoBean = bean; SKN`2hD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); adcE'fA<_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); EME|k{W  
if(tmpFile.exists ()) ;JT-kw6l5K  
{ `$ 9x1dx  
bFirst = false; a58H9w"u)  
read_nPos(); &6!)jIWJ  
} <'Eme  
else ;igIZ$&  
{ H%td hu\e  
nStartPos = new long[bean.getNSplitter()]; (%6P0*  
nEndPos = new long[bean.getNSplitter()]; g$-PR37(  
} 9.-S(ZO  
rs[T=CQ  
;[DU%f  
!f [_+CD  
} 6d}lw6L  
@Nx 9)  
hn@08t G  
public void run() U7F!Z( 9  
{ =UQ3HQD  
//获得文件长度 0s[Hkhls  
//分割文件 CAhXQ7w'Z  
//实例FileSplitterFetch gr2U6gi  
//启动FileSplitterFetch线程 FW4<5~'  
//等待子线程返回 W{+2/P  
try{ 3nQ`]5.Q w  
if(bFirst) #c!lS<z  
{ Ld~/u]K%V  
nFileLength = getFileSize(); C&%_a~  
if(nFileLength == -1) cm+Es6;  
{ TD0 B%  
System.err.println("File Length is not known!"); W ac&b  
} XpHrt XD  
else if(nFileLength == -2) va@Lz&sAE%  
{ wP@(?z  
System.err.println("File is not access!"); kTgEd]^&D  
} gwMNYMI  
else _G@GpkSe>  
{ ZY+qA  
for(int i=0;i<nStartPos.length;i++) ;A*]l' [-  
{ ?:q*(EC<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); XRi8Gpg  
} m:2^= l4  
for(int i=0;i<nEndPos.length-1;i++) NXrlk  
{ CD~.z7,LC  
nEndPos = nStartPos[i+1]; >kVz49j  
} &h/X ku&0  
nEndPos[nEndPos.length-1] = nFileLength; a`>B Ly5o  
} U5de@Y  
} DvvK^+-~  
#\m<Sz5Gp#  
onzxx4bax  
//启动子线程 f+!(k)GWd  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; k9!{IScq  
for(int i=0;i<nStartPos.length;i++) F JyT+  
{ q_58;Bv  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (!WD1w   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xb8!B  
nStartPos,nEndPos,i); `|q(h Ow2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~]2K ^bh8&  
fileSplitterFetch.start(); 5rik7a)Z]  
} ?e 4/p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5\ nAeP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); F)eelPZ+,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4V`G,W4^J  
nEndPos = " + nFileLength); G"t5nHY\.  
// fileSplitterFetch[nPos.length-1].start(); a:w#s}bL  
j#ab_3xH  
^1];S^nD  
//等待子线程结束 G 3ptx! D  
//int count = 0; NgPk&niM  
//是否结束while循环 bk[!8- b/a  
boolean breakWhile = false; R6->t #n,  
zO6oT1I  
\9T7A&  
while(!bStop) P*j|.63  
{ 6'f;-2  
write_nPos(); #H~64/  
Utility.sleep(500); M\BRcz  
breakWhile = true; 0g8NHkM:2a  
K-Ef%a2#`  
gB33?  
for(int i=0;i<nStartPos.length;i++) ;$g?T~v7  
{ V'gh 6`v  
if(!fileSplitterFetch.bDownOver) 5{,<j\#L  
{ 9pfIzs su3  
breakWhile = false; ECmW`#Otb)  
break; Z% UP6%  
} 'I;zJ`Trd  
} $XH^~i;  
if(breakWhile) Eu3E-K@y  
break; ");a3hD  
`R^gU]Z,  
$6IJ P\  
//count++; VIf.q)_k  
//if(count>4) iy.\=Cs$N  
// siteStop(); &rR2,3r=  
} N;%6:I./  
F#E3q|Q"BS  
v3>UV8c'  
System.err.println("文件下载结束!"); JucY[`|JV  
} y@yD5$/  
catch(Exception e){e.printStackTrace ();} 8&dF  
} ?a]mDx>xh  
owv[M6lbD  
9M c ae 31  
//获得文件长度 _yR^*}xJb  
public long getFileSize() COlaD"Y  
{ Z;"vW!%d  
int nFileLength = -1; f|(M.U-  
try{ 6Kz,{F@  
URL url = new URL(siteInfoBean.getSSiteURL()); I]q% 2ie  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K*dCc}:`  
httpConnection.setRequestProperty("User-Agent","NetFox"); \|[;Z"4l  
G3v5KmT  
 %;!.n{X  
int responseCode=httpConnection.getResponseCode(); \_fv7Fdp{  
if(responseCode>=400) |y!A&d=xYn  
{ V=3b&TkE  
processErrorCode(responseCode); Flb&B1  
return -2; //-2 represent access is error ],].zlN  
} \'j|BJ~L f  
% & bY]w  
,hmL/K0"(5  
String sHeader; &)<)^.@3G^  
sDV Q#}a  
V(*(F7+  
for(int i=1;;i++) 93hxSRw  
{ ,2ar7 5Va  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1h5 Akq  
//Utility.log(in.readLine()); C7AUsYM  
sHeader=httpConnection.getHeaderFieldKey(i); 5F"jk d+  
if(sHeader!=null) 9N3eN  
{ gQ.Sa j $  
if(sHeader.equals("Content-Length")) FVBYo%Ap  
{ x,Vr=FB  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); hpk7 A np  
break; RG`1en  
} U m+8"W  
} P0b7S'a4!  
else $ME)#(  
break; IE~ |iQ?-  
} 0m ? )ROaJ  
} ~Cjn7  
catch(IOException e){e.printStackTrace ();} a[TMDU;(/4  
catch(Exception e){e.printStackTrace ();} T[j,UkgGo  
u#SWj,X  
k VQ\1!  
Utility.log(nFileLength); Aiea\j Bv  
Wm5 dk9&x  
rVsJ`+L  
return nFileLength; <54 S  
} Rx}Gz$   
vr^qWn  
,Y48[_ymm  
//保存下载信息(文件指针位置) Du){rVY^d  
private void write_nPos() sx<%2  
{ %~S&AE-  
try{ DlNX 3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); igAtRX%Qx  
output.writeInt(nStartPos.length); _J[P[(ab  
for(int i=0;i<nStartPos.length;i++) xkR0  
{ GuL<Z1<c  
// output.writeLong(nPos); >F&47Yn  
output.writeLong(fileSplitterFetch.nStartPos); Sa5G.^ XI  
output.writeLong(fileSplitterFetch.nEndPos); )\^-2[;  
} pD]OT-8  
output.close(); ~u+9J}  
} 5/z/>D;  
catch(IOException e){e.printStackTrace ();} =nHgDrA_  
catch(Exception e){e.printStackTrace ();} gPc=2  
} t&DEb_"De  
Ti&z1_u  
8HdAFRw  
//读取保存的下载信息(文件指针位置) -|\ZrE_h  
private void read_nPos() ^sg,\zD 'X  
{ C"enpc_C/  
try{ W*w3 [_"sr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); WMP,\=6k0  
int nCount = input.readInt(); tklH@'q  
nStartPos = new long[nCount]; ^zgo#J 5O  
nEndPos = new long[nCount]; /H+a0`/  
for(int i=0;i<nStartPos.length;i++) 'A[dCc8O  
{ BFW&2  
nStartPos = input.readLong(); GvlS%  
nEndPos = input.readLong(); OK g qT!  
} A. w:h;7  
input.close(); vVcob }ZH  
} ei5~&  
catch(IOException e){e.printStackTrace ();} 4nz35BLr  
catch(Exception e){e.printStackTrace ();} z&^&K}  
} k-""_WJ~^  
c6/=Gq{.  
sUm'  
private void processErrorCode(int nErrorCode) W+1^4::+  
{ B,fo(kG  
System.err.println("Error Code : " + nErrorCode); FU<Jp3<%  
} W|(1Y D  
.XhrCi Z  
gKCX|cULY  
//停止文件下载 FNId ;  
public void siteStop() ]jRfH(i  
{ o,3a4nH;  
bStop = true; 8sK9G` k  
for(int i=0;i<nStartPos.length;i++) uA#;G/$  
fileSplitterFetch.splitterStop(); {cw /!B  
q6X1P" %.  
EDs\,f}  
} 5+ MS^H  
} ,wdD8ZT'Ip  
//负责部分文件的抓取 hwNf~3eJk  
**FileSplitterFetch.java h3@v+Z<}  
*/ t<?,F  
package NetFox; Y:)e(c"A  
B^jc3 VsR  
-`TEVS?`l  
import java.io.*; 9k[9P;"F:  
import java.net.*; XHGFf_kW_N  
LB?u8>a' I  
%GIr&V4|  
public class FileSplitterFetch extends Thread { `x%>8/  
"Os_vlapHo  
ps DetP  
String sURL; //File URL u,Kly<0j  
long nStartPos; //File Snippet Start Position S?BG_J6A7  
long nEndPos; //File Snippet End Position 26x[X.C:  
int nThreadID; //Thread's ID 1 I",L&S1  
boolean bDownOver = false; //Downing is over {P#|zp4C{  
boolean bStop = false; //Stop identical U\!X,a*ts{  
FileAccessI fileAccessI = null; //File Access interface CQDkFQq-dq  
_/<x   
z,%$+)K  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException yyy|Pw4:Z  
{ X+]G-  
this.sURL = sURL; QUQ'3  
this.nStartPos = nStart; NSA-}2$  
this.nEndPos = nEnd; Tc3yS(aq  
nThreadID = id; liz~7RY4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 WvZ8/T'x  
} 0NX,QD  
4tmAzD  
l0i^uMS  
public void run() "i W"NFO  
{ g5r(>,vY  
while(nStartPos < nEndPos && !bStop) ! #2{hQRu  
{ xW Q`tWA:J  
.y:U&Rw4  
mBON$sF|  
try{ b<gr@WF  
URL url = new URL(sURL); >!)DM]Ri  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Jma1N;d  
httpConnection.setRequestProperty("User-Agent","NetFox"); P\)iZiGc  
String sProperty = "bytes="+nStartPos+"-"; l_%6  
httpConnection.setRequestProperty("RANGE",sProperty); g_COp "!~9  
Utility.log(sProperty); <dhM\^ [  
c6]D-YNF G  
hp L;bM'  
InputStream input = httpConnection.getInputStream(); ZLAy- 9^Y  
//logResponseHead(httpConnection); R@k&SlL'`  
wZZt  
Rr|VD@%  
byte[] b = new byte[1024]; i@M [>~  
int nRead; Y,zxbXZv'5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) q{;:SgZ  
{ Nf1-!u7  
nStartPos += fileAccessI.write(b,0,nRead); l0A&9g*l2  
//if(nThreadID == 1) QGmn#]w\\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SS.dY""89  
} UFb )AnK  
/ FEVmH?  
K:30_l<  
Utility.log("Thread " + nThreadID + " is over!"); !f&g-V  
bDownOver = true; @/-\k*T  
//nPos = fileAccessI.write (b,0,nRead); "C0Q(dr/n  
} b(O3@Q6[  
catch(Exception e){e.printStackTrace ();} y:qUn!3  
} 7o5BXF  
} V[vl!XM  
s#=7IH30  
m5Di=8  
//打印回应的头信息 N7R!C)!IL  
public void logResponseHead(HttpURLConnection con) F6 flIG&h  
{ i5,kd~%O  
for(int i=1;;i++) x>`%DwoRI  
{ t" Z6[XG  
String header=con.getHeaderFieldKey(i); :${HQd+  
if(header!=null) zu|\fP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2WxQ(:d=  
Utility.log(header+" : "+con.getHeaderField(header)); ) M BQuiL  
else w %BL  
break; 63,H{  
} K~eh P[^  
} _X"N1,0  
K1!j fp  
L<{i ,'M  
public void splitterStop() ?]Xpi3k  
{ A`o8'+`C  
bStop = true; HcSXsF  
} m:o<XK[>  
eb"5- 0  
__GqQUQ  
} e|WJQd4+S  
.O}%  
q2:6QM&  
/* 'K{Z{[s{  
**FileAccess.java g:Xhw$x9  
*//文件访问(定位,写) +<3X J7D  
package NetFox; b-Q>({=i  
import java.io.*; I( 7NQ8H x  
o;<Xo&  
&/]Fc{]^$f  
public class FileAccessI implements Serializable{ 0eu$ W  
H{?vbqQ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Jk=I^%~  
RandomAccessFile oSavedFile; KRMQtgahc  
long nPos; ^qQZT]  
y^v6AM  
iq( E'`d  
public FileAccessI() throws IOException dD|OSB7 I7  
{ v4c[(&  
this("",0); po Vx8oO8  
} `q*M4,  
};jN\x?&q  
22M1j5  
public FileAccessI(String sName,long nPos) throws IOException K<ft2anY5  
{ ,-d 0b0  
oSavedFile = new RandomAccessFile(sName,"rw"); PV\+P6aIb  
this.nPos = nPos; jun_QiU:2  
oSavedFile.seek(nPos); m\r@@!  
} p=GBUII #  
:AF =<X*5  
QoIT*!  
public synchronized int write(byte[] b,int nStart,int nLen) mA+&Io  
{ 6NM:DI\%  
int n = -1; p#?7 w  
try{ <vh/4  
oSavedFile.write(b,nStart,nLen); ]X5 9  
n = nLen; nv%rJy*w[  
} 2ZMb<b4H  
catch(IOException e) v)l8@.  
{ W;L7SF g)  
e.printStackTrace (); b8"?VS5-"  
} ]?+p5;{y4  
`c5"d  
f~y%%+{p  
return n; sRx63{  
} ;q:zT\A  
dWUm\t'#  
. Z.)t  
} !GLz)#SBl  
,dov<U[ia  
g-H N  
/* v~V5`%  
**SiteInfoBean.java =;3Sx::=  
*/ / !Wu D\B  
package NetFox; BuWHX>H  
l@H  
Y/ >&0wj)d  
public class SiteInfoBean { TI#''XCB5  
jR2 2t`4  
9{}1r2xW  
private String sSiteURL; //Site's URL z4+k7a@jn  
private String sFilePath; //Saved File's Path 8:>1F,  
private String sFileName; //Saved File's Name >.'*) @vQi  
private int nSplitter; //Count of Splited Downloading File #PanfYR  
H!nr^l'+  
AW_(T\P:u  
public SiteInfoBean() F\AX :  
{//nSplitter的缺省值为5 C>$E%=h+_  
//default value of nSplitter is 5 `m?c;,\  
this("","","",5); /VzI'^  
} gb> }v7  
]Nl=wZ#`  
]*FVz$>XM  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]dk8lZ;bo  
{ PBxCx3a{  
sSiteURL= sURL; X4t s)>"d  
sFilePath = sPath; ;A'Z4=*~  
sFileName = sName; 2 :mn</z  
this.nSplitter = nSpiltter; bKQ"ax>6p  
rN<b?KE  
H nUYqhZS  
} Eu-RNrYh#  
s#DaKPC  
L19C<5>  
public String getSSiteURL() &f^l ^K 5:  
{ Jn3 An  
return sSiteURL; *l;B\=KR  
} y^Kph# F"  
0B&Y ]*  
1~ t{aLPz  
public void setSSiteURL(String value) =ng\ 9y[;D  
{ ks97k8B  
sSiteURL = value; 80&.JP.  
} TJ'[--  
+$(2:S*r  
K+8-9$w6  
public String getSFilePath() ?(m jx  
{ \&3"<6xA  
return sFilePath; * U$!I?  
} 2aB^WY'tC  
B`o]*"xkB  
0i|oYaC  
public void setSFilePath(String value) rBTeb0i?  
{ C2xL1`  
sFilePath = value; )+"'oY$]}  
} |t) }VM%  
!x>%+&c>k  
T?1Du"d8  
public String getSFileName() VX+jadYdq  
{ dT$M y`>  
return sFileName; +1!qs,  
} V$icWu  
*^wB!{.#  
{^rs#, W  
public void setSFileName(String value) k`9)=&zX+  
{ `S.ZS}~!F  
sFileName = value; )0e2ic/  
} d]i(h~?_  
RUUk f({(  
O Xi@c;F  
public int getNSplitter() ;Y mTw  
{ "zY](P  
return nSplitter; e9Pk"HHl  
} ~-t>z  
UMp/ \&0  
A@D2+fS  
public void setNSplitter(int nCount) +|{RE.DL  
{ X3:XTuV   
nSplitter = nCount; )T66<UDK|  
} ww{_c]My  
} kR@Yl Yo  
q@~L&{  
~h=X8-D  
/* JwRF(1_sM  
**Utility.java q4$+H{xB  
*/ F3lw@b3])  
package NetFox; xc:!cA{V  
<uk1?Q g  
P;8>5;U4-  
public class Utility { Enq|Y$qm  
T<joR R  
0T5=W U  
public Utility() =!UR=Hq  
{ /.eeO k  
?Xo*1Z =  
70Yjv 1i  
} $1zvgep  
4E[!,zvl  
//线程睡眠 LrV{j?2@  
public static void sleep(int nSecond) mNAY%Wn6k  
{ 9 ASb>A2~  
try{ q7m6&2$[  
Thread.sleep(nSecond); vF/ =J  
} )|<_cwz  
catch(Exception e) W Qzj[  
{ lhYn5d)DV  
e.printStackTrace (); q *AQq=  
} MfBdNdox7  
} gbStAr.  
A +w v-~3  
//日志 o1OBwPj  
public static void log(String sMsg) Gy Qm/I  
{ }Y1>(U  
System.err.println(sMsg); w_4]xgS:  
} =AEz9d ciS  
eL.7#SIr}  
h2;z 4  
public static void log(int sMsg) R,!Q Zxmg  
{ daAyx-  
System.err.println(sMsg); TfZ6F8|B  
} MZSxQ8  
} Ti;Ijcq8  
fKa\7{R  
xg{HQQ|TC  
/* j?|* LT$%7  
**TestMethod.java -(JUd4#  
*/ {,j6\Cj4  
package NetFox; '69ZdP/xX  
kF V7l  
yWHiw<  
public class TestMethod { Zx?b<"k  
6ZqgY1  
0gF!!m  
public TestMethod() cM&'[CI  
{ ///xx/weblogic60b2_win.exe Y/8K;U|  
try{ nxap\Lf  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }98>5%Uv  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &yz&LNn'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Er:?M_ev  
fileFetch.start(); 2 vKx]w  
} >1irSUj"~  
catch(Exception e){e.printStackTrace ();} A~{f/%8D  
AzpV4(:an.  
$ 'QdFkOr  
} `Xc irfp  
4*UP. r@  
:PnSQjV:  
public static void main(String[] args) 4R) |->"  
{ <3O T>E[  
new TestMethod(); "!Rw)=7O  
} IdRdW{o  
} &,-p',\-  
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