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http断点续传简单实现(java)

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/* Vs"Z9p$U  
**SiteFileFetch.java hImCy9i}  
*/ v`fUAm/  
package NetFox; r[lHYO  
import java.io.*; GwvxX&P  
import java.net.*; J h"]iN  
<HD/&4$[  
K{iYp4pU  
public class SiteFileFetch extends Thread { <(iOzn  
v6r w.  
nO/5X>A,Zw  
SiteInfoBean siteInfoBean = null; //文件信息Bean <@yyx7  
long[] nStartPos; //开始位置 vxgm0ZOMN  
long[] nEndPos; //结束位置 ~\^8 ^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 r B)WHx<  
long nFileLength; //文件长度 uZ^i8;i  
boolean bFirst = true; //是否第一次取文件 L`!sV-.  
boolean bStop = false; //停止标志 I@\{6hw  
File tmpFile; //文件下载的临时信息 |&'*Z\*ya  
DataOutputStream output; //输出到文件的输出流 M]2 c-  
7%<jZ =  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Ns $PS\  
public SiteFileFetch(SiteInfoBean bean) throws IOException LY>JE6zTt  
{ /t/q$X  
siteInfoBean = bean; &><`?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fx|9*|E  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^?A+`1-  
if(tmpFile.exists ()) -Av/L>TxlI  
{ RS1oPY  
bFirst = false; =f["M=)ZJ  
read_nPos(); -lp_~)j^  
} 1@ina`!1O  
else :JS} (  
{ u>eu47"n!  
nStartPos = new long[bean.getNSplitter()]; >!2'|y^  
nEndPos = new long[bean.getNSplitter()]; "gO5dZ\0  
} pI!55w|  
V]AL'}( 0  
'*k\IM{h  
C+k>Ajr  
} X*~YCF[_  
s6egd%r  
HI?>]zz|  
public void run() {\e}43^9N  
{ 5YCbFk^  
//获得文件长度 jyC6:BNust  
//分割文件 qL#R XUTP  
//实例FileSplitterFetch @|@43}M]C-  
//启动FileSplitterFetch线程 t|q=NK/  
//等待子线程返回 }>w; +XU  
try{ d?K8Ygz  
if(bFirst) dO@iq^9-  
{ 9~_6mR<  
nFileLength = getFileSize(); Gl:AS PZ6  
if(nFileLength == -1) x:xQXjJ  
{ {)y4Qp  
System.err.println("File Length is not known!"); _H,RcpyJ  
} 6i4j(P  
else if(nFileLength == -2) V;V9_qP,  
{ \5Jv;gc\\  
System.err.println("File is not access!"); p .HA `R>  
} `#ztp)&  
else ~IXfID!8  
{ jt3SA [cy  
for(int i=0;i<nStartPos.length;i++) j{=%~  
{ 2S;zze7)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); p5KNqqZZ  
} U]acm\^Z  
for(int i=0;i<nEndPos.length-1;i++) Z Kvh]  
{ #cs!`Ngb+  
nEndPos = nStartPos[i+1]; N_<n$3P\?f  
} >O _  
nEndPos[nEndPos.length-1] = nFileLength; X]!@xlwF\  
} 8vo} .JIl  
} fCfY.vd5  
m ";gD[m  
!S:@x.n@iR  
//启动子线程 IFY !3^;zO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; K"1J1>CHQ  
for(int i=0;i<nStartPos.length;i++) kD>vQ?  
{ [wR8q,2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >W<5$.G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J 0 P  
nStartPos,nEndPos,i); PG!vn@b6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _X[c19q  
fileSplitterFetch.start(); J\V(MN,  
} [OcD#~drO  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), riL!]'akV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xpM~* Gpm  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )N<!3yOz  
nEndPos = " + nFileLength); >U)O@W)  
// fileSplitterFetch[nPos.length-1].start(); J[l K  
H/$q]i*#K  
*"ShE=\p  
//等待子线程结束 0u_'(Z-^2  
//int count = 0; +[ zo2lBx  
//是否结束while循环 To`?<]8  
boolean breakWhile = false; w(D9'  
{@A2jk\  
Oq5k4  
while(!bStop) ;qMlGXW*q  
{ V'.|IuN  
write_nPos(); @-}]~|<  
Utility.sleep(500); brWt  
breakWhile = true; =S,<yQJ  
9o`3g@6z  
u W T[6R  
for(int i=0;i<nStartPos.length;i++) .Dm{mV@*T  
{ 5*$Zfuf  
if(!fileSplitterFetch.bDownOver) ^= G+]$8  
{ 9x!y.gx  
breakWhile = false; %u}sVRJ  
break; vknFtpx  
} BE~[%6T7  
} ;"Y6&YP<  
if(breakWhile) #F@7>hd1  
break; M6iKl  
OT i3T1&  
BP$#a #  
//count++; vvxj{fxb)  
//if(count>4) 4(82dmKO  
// siteStop(); }3 }=tN5  
} ([~`{,sv  
c29Z1Zs2)  
1tdCzbEn+  
System.err.println("文件下载结束!"); j&.BbcE45  
} d}_c (  
catch(Exception e){e.printStackTrace ();} 7 w,FA  
} L ]c9  
S)yV51^B  
DlI5} Jh  
//获得文件长度 mI#; pO2  
public long getFileSize() ]6 wi  
{ ?C35   
int nFileLength = -1; T*yveo &j  
try{ "Ycd$`{Vgt  
URL url = new URL(siteInfoBean.getSSiteURL()); <h9\A&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !$Z"\v'b  
httpConnection.setRequestProperty("User-Agent","NetFox"); \<**SSN  
m{c#cR  
-::%9D}P|  
int responseCode=httpConnection.getResponseCode(); CN(4;-so)  
if(responseCode>=400) sfE8b/Z8  
{  HU9y{H  
processErrorCode(responseCode); c ?XUb[  
return -2; //-2 represent access is error .Er/t"Qs;  
} '.,.F0{x  
8 -A7  
VsEAo  
String sHeader; JxJntsn  
+_P 2S  
:g#it@  
for(int i=1;;i++) E e>j7k.G.  
{ uW=NH;u  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &,]+>  
//Utility.log(in.readLine()); D|9fHMg %  
sHeader=httpConnection.getHeaderFieldKey(i); vWs c{9  
if(sHeader!=null) j*d~h$[k  
{ ^~ $&  
if(sHeader.equals("Content-Length")) "|`9{/]  
{ X>7]g670@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \*aLyyy3  
break; <9a_wGs  
} @l GnG  
} XWpnZFjE  
else C)s1' =TZ  
break; GK?R76d  
} 30+l0\1  
} vfJk? (  
catch(IOException e){e.printStackTrace ();} 4uAafQ`@H  
catch(Exception e){e.printStackTrace ();} - oBas4J  
yX3H&F6  
)OC[;>F7  
Utility.log(nFileLength); 3z92Gy5cr  
% T\N@  
H^;S}<pxW  
return nFileLength; U^BXCu1km  
} z/k~+-6O  
&\|<3sd(  
ok%!o+nk.  
//保存下载信息(文件指针位置) ;<@6f@  
private void write_nPos() A5<Z&Y[  
{  iLcadX  
try{ %C0O?q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); E :=KH\2f  
output.writeInt(nStartPos.length); )+4}Ix/q  
for(int i=0;i<nStartPos.length;i++) E(kpK5h{  
{ SoU'r]k1x  
// output.writeLong(nPos); Pl& `&N;  
output.writeLong(fileSplitterFetch.nStartPos); yVQz<tX|  
output.writeLong(fileSplitterFetch.nEndPos); Y zW7;U S  
} "UGj4^1f  
output.close(); r5fkt>HZ  
} 3H#/u! W  
catch(IOException e){e.printStackTrace ();} #r)1<}_e#  
catch(Exception e){e.printStackTrace ();} ugCS &  
} h?3l  
Ny,A#-?  
)-KE4/G  
//读取保存的下载信息(文件指针位置) m_02"'  
private void read_nPos() \}QuNwc   
{ 2$zq (  
try{ a& aPBv1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); afiK!0col2  
int nCount = input.readInt(); vLFaZ^(  
nStartPos = new long[nCount]; OMI!=Upz  
nEndPos = new long[nCount]; i2a"J&,6O  
for(int i=0;i<nStartPos.length;i++) L_1_y, 0N  
{ [2 w <F[  
nStartPos = input.readLong(); ]q[  
nEndPos = input.readLong(); \*!%YTZ~  
} 9'#.>Q>0=j  
input.close(); e$+f~~K  
} a05:iFoJ  
catch(IOException e){e.printStackTrace ();} *R\/#Y|  
catch(Exception e){e.printStackTrace ();} -b\ V(@5  
} \.;ct  
yX.5Y|A<  
ElR&scXi__  
private void processErrorCode(int nErrorCode) +<WRB\W  
{ NU&^7[!yl  
System.err.println("Error Code : " + nErrorCode); KR+BuL+L  
} 4B8Se  
Y:!/4GF  
]VG84bFm  
//停止文件下载 ?~JxO/K  
public void siteStop() MRg\FR 2>1  
{ T19rbL_  
bStop = true; u~- fK'/!|  
for(int i=0;i<nStartPos.length;i++) QB3d7e)8>  
fileSplitterFetch.splitterStop(); }d3N`TT  
t#pqXY/;D  
eIUuq&(  
} i=X*  
} A6UdWK  
//负责部分文件的抓取 a}qse5Fr  
**FileSplitterFetch.java N[x@j)w-`  
*/ YUVc9PV)Ws  
package NetFox; 56=K@$L {F  
RnA&-\|*  
Bw]L2=d  
import java.io.*; 9p\Hx#^  
import java.net.*; 7hN6IP*so  
Dj ]Hgg  
mj~N]cxB  
public class FileSplitterFetch extends Thread { y }&4HrT&  
<% 7P  
}y-;>i#m=g  
String sURL; //File URL | 2.e0Z]k  
long nStartPos; //File Snippet Start Position j`|^s}8t  
long nEndPos; //File Snippet End Position Ld}(*-1i  
int nThreadID; //Thread's ID cbu nq"  
boolean bDownOver = false; //Downing is over NM1cyZ  
boolean bStop = false; //Stop identical C*EhexK,}  
FileAccessI fileAccessI = null; //File Access interface 2 ]DCF  
7Z`Mt9:Ht  
N[bR&# p  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eC^0I78x  
{ @W1WReK]f  
this.sURL = sURL; 3r-VxP 5n  
this.nStartPos = nStart;  [ }p  
this.nEndPos = nEnd; _/jUs_W  
nThreadID = id; Ku0H?qft(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .kbr?N,'  
} 0/SC  
L* k hj3;  
qJ X+[PJ  
public void run() B3cf] S%  
{ AFINm%\/0  
while(nStartPos < nEndPos && !bStop) ~X~xE]1o|U  
{ iz9\D*or  
}c35FM,  
_z<Y#mik  
try{ cVB|sYdf  
URL url = new URL(sURL); k_K,J 6_)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e+F}9HR7  
httpConnection.setRequestProperty("User-Agent","NetFox"); j(Fa=pi  
String sProperty = "bytes="+nStartPos+"-"; zM_DE  
httpConnection.setRequestProperty("RANGE",sProperty); x5fgF;  
Utility.log(sProperty); rb *C-NutE  
J}) $  
wuIsO;}/9  
InputStream input = httpConnection.getInputStream(); c_ qcb7<~.  
//logResponseHead(httpConnection); - - i&"  
\'; t*  
;# R3k  
byte[] b = new byte[1024]; nIV.9#~&  
int nRead; ;w+:8<mM}a  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5Cc6 , ]  
{ Dm|gSv8d,  
nStartPos += fileAccessI.write(b,0,nRead); y$j1?7  
//if(nThreadID == 1) <ELziE~>V  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BcZEa^^~os  
} %z-dM` i  
f[JI/H>  
d s|8lz,  
Utility.log("Thread " + nThreadID + " is over!"); ?jNF6z*M6  
bDownOver = true; qeQC&U y;  
//nPos = fileAccessI.write (b,0,nRead); fuNl4BU  
} P[rAJJN/E  
catch(Exception e){e.printStackTrace ();} 2I]]WBW#:  
} rV8(ia  
} |'U,/  
";)r*UgR{B  
rPiiC/T.`  
//打印回应的头信息 lFiq<3Nk  
public void logResponseHead(HttpURLConnection con) ER~T'-YMS  
{ E6'8Zb  
for(int i=1;;i++) 3AdP^B<  
{ x1 ;rb8  
String header=con.getHeaderFieldKey(i); &5kZ{,-eM  
if(header!=null) @9_nwf~X4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q4sl=`L5Sp  
Utility.log(header+" : "+con.getHeaderField(header)); (MgL"8TS  
else ur/Oc24i1n  
break; 3E<aiGU  
} y\F`B0#$  
} O%YjWb  
@D fkGm[%  
(@ %XWg  
public void splitterStop() "C:rTIH  
{ $"Y3mD}?L  
bStop = true; \3%W_vU_  
} +Fk4{p  
C+/Eqq^(  
NniX/fk  
} a);O3N/*I  
{ A:LAAf[6  
H/^ ~<U#p  
/* _, \y2&KT  
**FileAccess.java (g%JK3  
*//文件访问(定位,写) 5*JV )[  
package NetFox; {[Uti^)m%  
import java.io.*; 6PiEa(  
CCuxC9i7  
Rz`@N`U  
public class FileAccessI implements Serializable{ v\fzO#vj  
gXq!a|eH  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 kk 8R  
RandomAccessFile oSavedFile; t *o7,  
long nPos; r> Fec  
o{9?:*?7  
Z -pyFK\  
public FileAccessI() throws IOException jmRhAJV  
{ kj x>  
this("",0); c*.G]nRc  
} D",A$(lG  
xM%H~(  
hX0RET  
public FileAccessI(String sName,long nPos) throws IOException nURvy}<r  
{ y!S^xS  
oSavedFile = new RandomAccessFile(sName,"rw"); VKT@2HjNT`  
this.nPos = nPos; V)2"l"Kt  
oSavedFile.seek(nPos); +7Sf8tg\  
} zTkFX67)  
3sS=?q  
NV&;e[z  
public synchronized int write(byte[] b,int nStart,int nLen) U^B"|lc:[  
{ K{|w 43>D  
int n = -1; !$D&6M|C8l  
try{ Xf6fH O  
oSavedFile.write(b,nStart,nLen); 40 A&#u9o  
n = nLen; UE"7   
} HvAE,0N  
catch(IOException e) j?=VtVP  
{ H9sZR>(^  
e.printStackTrace (); $ b4*/vMr  
} cE^kpnVq|<  
:[ L{KFQU  
c L?\^K)  
return n; D._{E*vg  
} U%Dit  
j -#E?&2  
0xN!DvCg>.  
} (2: N;  
: @s8?eg  
(gLea  
/* XxhsPFv  
**SiteInfoBean.java YQN.Ohtv*F  
*/ *f{7  
package NetFox; g+igxC}2z  
/d[Mss  
>g=^,G}y  
public class SiteInfoBean { TKK,Y{{  
1d`cTaQ-  
K-Re"zsz  
private String sSiteURL; //Site's URL 8098y,mQe  
private String sFilePath; //Saved File's Path bi+9R-=&  
private String sFileName; //Saved File's Name KCE=|*6::|  
private int nSplitter; //Count of Splited Downloading File 5n:nZ_D  
]Fxku<z7|  
HHZ`%  
public SiteInfoBean() -48`#"xy  
{//nSplitter的缺省值为5 ya#RII']  
//default value of nSplitter is 5 iA]DE`S  
this("","","",5); n4Vwao/9x  
}  64SW  
H4W1\u  
[U swf3  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) S[Vtq^lU  
{ |0lLl^zp  
sSiteURL= sURL; kPWBDpzN  
sFilePath = sPath; :RHm*vt  
sFileName = sName; I<sfN'FpT  
this.nSplitter = nSpiltter; TFo}\B7  
)GK+  
en%J!<&W{K  
} ># INEO  
x9h?e`  
;r3}g"D@  
public String getSSiteURL() )Q~C4C-j  
{ ~H7!MC~K  
return sSiteURL; H*GlWgfG  
} w:v=se"U  
N=q#y@L  
<o2,HTWNPS  
public void setSSiteURL(String value) ti}f&w ICJ  
{ Zgy7!AF!  
sSiteURL = value; XJc ,uj7  
} P`tyBe#=  
\Fq1^ 8qa  
Sg_O?.r  
public String getSFilePath() 9YAM#LBTWi  
{ *-6?  
return sFilePath; iM"asEU  
} D'<$ g  
Cpe#[mE  
+N7"EROc  
public void setSFilePath(String value) ^}hJL7O'  
{ z4bN)W )p  
sFilePath = value;  ![ a  
} dIvy!d2l  
pp<E))&R  
o OQ'*7_  
public String getSFileName() ewpig4  
{ vmLpm xS  
return sFileName; fa4=h;>a+  
} 5} G:D  
yWNOG 2qAP  
0t+])>  
public void setSFileName(String value) 7|Xe&o<n  
{ g>_OuQ|c  
sFileName = value; b;*c:{W)  
} _H8*ReFG  
Zb"jB$58  
0iV;g`%  
public int getNSplitter() Yh$fQ:yi\&  
{ Ia#"/`||  
return nSplitter; <*_o0;h|  
} d+0^u(gc!8  
nZxSMN0]  
+mLD/gK`  
public void setNSplitter(int nCount) 7k'gt/#up  
{ &sdx`,  
nSplitter = nCount; 6Kp}_^|z  
} @`S.@^%7fO  
} w:Ra7ExP  
$R?@L  
Ik Qe~;Y  
/* _$5@uL{n"^  
**Utility.java `w+1C&>^[  
*/ 4v Lw?_".  
package NetFox; >L=;"+B0U&  
e8-ehs>  
T<6GcI>A  
public class Utility { l#$TYJi  
NV6G.x  
_4v"")Xe  
public Utility() !VRo*[yD@  
{ TM-Fu([LMV  
AuXs B  
jM@?<1  
} V'I T1~  
!3V{2-y$-  
//线程睡眠 )b0];&hw]  
public static void sleep(int nSecond) 7h`^N5H.q  
{ 8SZK:VE@  
try{ `;cz;"  
Thread.sleep(nSecond); !D;c,{Oz  
} ?A&%Cwj  
catch(Exception e) G|*G9nQ  
{ XXm'6xD-  
e.printStackTrace (); bcn7,ht  
} bb1  f/C%  
} JD*8@N  
G\ex^&M  
//日志 , D"]y~~I5  
public static void log(String sMsg) (:n|v%  
{ (v^Z BM_  
System.err.println(sMsg); "mA1H]r3  
} mX;H((  
Cfv]VQQE  
p/&HUQQk  
public static void log(int sMsg) P0 b4Hq3  
{ ({ k7#1 h8  
System.err.println(sMsg); X}W)3v  
} ^1 ;BiQ  
} P,ydt  
^V .'^=l  
h/?6=D{  
/* SY T$3|a  
**TestMethod.java ;MPKJS68@  
*/ S3y246|4  
package NetFox; ]2$x| #Gg}  
O|e}   
x*q35K^PE  
public class TestMethod { V:Mk)8Gf|  
`tVy_/3(9  
UP8{5fx'  
public TestMethod() U=QA  e  
{ ///xx/weblogic60b2_win.exe w & P&7  
try{ ]\dHU.i  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); t^U^Tr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); SiTeB)/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M1{(OY(G  
fileFetch.start(); s[X B#)H4  
} x.UaQ |F  
catch(Exception e){e.printStackTrace ();} 328L)BmW  
V|: qow:F  
Z&Pu8zG /m  
} lDN?|YG  
q3+8]-9|5  
D/:3R ZF  
public static void main(String[] args) %*K;np-q{  
{ 1tGgDbJU  
new TestMethod(); MI*Sq\-i  
} !y[3]8Xxv  
} u"Y]P*[k  
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