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http断点续传简单实现(java)

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/* 2 ":W^P  
**SiteFileFetch.java Jk=_8Xvr`  
*/ ^&Vj m  
package NetFox; p}e1!q;N  
import java.io.*; 1DR ih>+#  
import java.net.*; mDdL7I  
[,0[\NC  
2 r';)8:  
public class SiteFileFetch extends Thread { )R^&u`k  
=kP|TR!o-  
)&{<gyS1  
SiteInfoBean siteInfoBean = null; //文件信息Bean +l27y0>t  
long[] nStartPos; //开始位置 i9+qU  
long[] nEndPos; //结束位置 *Roqie  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'ju'O#A9  
long nFileLength; //文件长度 5q,ZH6\ {  
boolean bFirst = true; //是否第一次取文件 xOt {Vsv  
boolean bStop = false; //停止标志 wTe 9OFv  
File tmpFile; //文件下载的临时信息 5"9 '=LV~  
DataOutputStream output; //输出到文件的输出流 BVzMgn;  
34F;mr"yp  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) j"r7M|Z+V  
public SiteFileFetch(SiteInfoBean bean) throws IOException !nDiAjj  
{ !O 0{ .k  
siteInfoBean = bean; ],-(YPiAD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `lcQ Yd<,4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,(3oAj\  
if(tmpFile.exists ()) 2DNB?,uP,'  
{ A}4 ",  
bFirst = false; p#0L@!,  
read_nPos(); ('z:XW96  
} `$t|O&z  
else po@Agyg5  
{ 3|Y2BA d  
nStartPos = new long[bean.getNSplitter()]; 0dW*].Gi:  
nEndPos = new long[bean.getNSplitter()]; -, uT8'  
} 'm^]X3y*  
{YK7';_E*  
+z|@K=d#|  
qM18 Ji*  
} #h}a   
;_ S D W  
M2Jb<y]  
public void run() hem>@Bp'V  
{ n{I1ZlEeh  
//获得文件长度 7{lWg x  
//分割文件 : "^/?Sd  
//实例FileSplitterFetch kx,3[qe'S  
//启动FileSplitterFetch线程 %v4*$E!f  
//等待子线程返回 5t,X;  
try{ i`}!<{k  
if(bFirst) WBWIHv{j  
{ k&9[}a*  
nFileLength = getFileSize(); Bn{i+8I  
if(nFileLength == -1) wx8Qz,Z  
{ Q9Vj8JO"{  
System.err.println("File Length is not known!"); _<%YLv  
} w0X})&,{`m  
else if(nFileLength == -2) 12@Ge]  
{ ~gdnD4[G  
System.err.println("File is not access!"); ?sv[vR(  
} a+^,EY  
else SUDvKP  
{ WP{U9YF2  
for(int i=0;i<nStartPos.length;i++) &NX7  
{ Qp9QS yMs}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8ZCR9%  
} 'Q"Mu  
for(int i=0;i<nEndPos.length-1;i++) eD|"?@cE  
{ !u;gGgQF  
nEndPos = nStartPos[i+1]; 3 MCV?"0  
} $ {e5Ka  
nEndPos[nEndPos.length-1] = nFileLength; wb>"'%  
} qr(t_qR&  
} yqC158 P  
AC*SmQ\>!  
PqMu2 e  
//启动子线程 R|92T*h  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;` h$xB(  
for(int i=0;i<nStartPos.length;i++) .%+anVXS  
{ Y;"jsK{$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PJT$9f~3;.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +4+c zfz  
nStartPos,nEndPos,i); i9|}-5ED  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L d{`k  
fileSplitterFetch.start(); + 2w<V0V_  
} m.FN ttkM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~ike&k{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); WRrg5&._q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hC4 M}(XM  
nEndPos = " + nFileLength); nRyx2\Py+  
// fileSplitterFetch[nPos.length-1].start(); vVZ+u4y  
\opcn\vW  
.X5A7 m  
//等待子线程结束 p=V1M-  
//int count = 0; {55f{5y3 c  
//是否结束while循环 YU XxQ|  
boolean breakWhile = false; D!8v$(#hR  
X]D:vuB  
J!}\v=Rn  
while(!bStop) oIniy{  
{ {Iz"]Wh<f  
write_nPos(); +,Or^p O=  
Utility.sleep(500); 3 }3C*w+  
breakWhile = true; Res4;C  
b4f3ef  
`(/xj{"Fr}  
for(int i=0;i<nStartPos.length;i++) KAi_+/]K_  
{ /l+"aKW 2  
if(!fileSplitterFetch.bDownOver) <\$?.tTZ {  
{ $3g M P+  
breakWhile = false; 7{]L{j-  
break; ]E)D})r`#  
} *\ B(-  
} &- !$qUli  
if(breakWhile)  F&lH5  
break; A%X=yqY  
F8#MI G   
I`s~.fZt  
//count++; C ^c <s  
//if(count>4) 7VskZbj\  
// siteStop(); Hy -)yR  
} mwMu1#  
%zo 6A1Q;  
s8'!1rHd  
System.err.println("文件下载结束!"); CpK:u! Dn  
} #s ' `bF^  
catch(Exception e){e.printStackTrace ();} :S}ZF$ $j%  
} v$+A!eo  
Y; iI =U  
K4o']{:U  
//获得文件长度 Aar]eY\  
public long getFileSize() 4.Fh4Y:$'  
{ `gF`Sgz  
int nFileLength = -1; bSn={O"M  
try{ g-,lY|a  
URL url = new URL(siteInfoBean.getSSiteURL()); {U@"]{3Qx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;JgSA&'e  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y]Z&  
X"mPRnE330  
&/:c?F?l  
int responseCode=httpConnection.getResponseCode(); CIsX$W  
if(responseCode>=400) AZ4:3}  
{ sva-Sd8  
processErrorCode(responseCode); &y7=tEV  
return -2; //-2 represent access is error \){_\{&  
} K>5 bb  
U#- 5",X|  
g/WDAO?d  
String sHeader; .:4*HB  
IwS<p -  
eD3\>Y.z  
for(int i=1;;i++) B5h)F> &G  
{ 7]Hf3]e>/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LNrM`3%2-  
//Utility.log(in.readLine()); |`kk mq  
sHeader=httpConnection.getHeaderFieldKey(i); pAq PHD=  
if(sHeader!=null) O*lIZ,!n  
{ <AiE~l| D  
if(sHeader.equals("Content-Length")) b6H7>x  
{ Ao*:$:k  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); XR p60i6f  
break; lqgR4  !  
} 2^75|Q  
} $P)-o?eer  
else pHye8v4fvi  
break; Cs,Cb2[  
}  _VM}]A  
} ;49sou  
catch(IOException e){e.printStackTrace ();} h,-i\8gq  
catch(Exception e){e.printStackTrace ();} #Ye0*`  
p&0 G  
.wTb/x  
Utility.log(nFileLength); ;Xqi;EA  
`Fe/=]< $  
bD3d T>(+  
return nFileLength; K6)IBV;  
} I>w|80%%  
[} d39  
9eE FX7  
//保存下载信息(文件指针位置) ;PqC *iz  
private void write_nPos() ?5;wPDsK  
{ ^vv 1cft  
try{ ME$J?3r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .QA1'_9  
output.writeInt(nStartPos.length); Tc>g+eS  
for(int i=0;i<nStartPos.length;i++) 0,):;O I  
{ jq_4x[  
// output.writeLong(nPos); sFvYCRw /  
output.writeLong(fileSplitterFetch.nStartPos); n=0^8QQ  
output.writeLong(fileSplitterFetch.nEndPos); ,J<+Wxz  
} w@YPG{"j  
output.close(); 7|bBC+;(  
} YguW2R=6]  
catch(IOException e){e.printStackTrace ();} FPZ@6  
catch(Exception e){e.printStackTrace ();} cRCji^,KJ  
} "(~fl<;  
|5q,%9_  
D vN0h(?  
//读取保存的下载信息(文件指针位置) m]'+Eye ]r  
private void read_nPos() ep`8LQf  
{ @Jlsx0i}}  
try{ _ 5b~3K/V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $]W*;MTI}  
int nCount = input.readInt(); &uV|Ie8@q  
nStartPos = new long[nCount]; J-G)mvkv  
nEndPos = new long[nCount]; cg_tJ^vrY  
for(int i=0;i<nStartPos.length;i++) Qw_> l}k/  
{ ;NAKU  
nStartPos = input.readLong(); ;<6S\  
nEndPos = input.readLong(); P]2 /}\f  
} Q84XmXm|  
input.close(); t-iQaobF  
} _`laP5~  
catch(IOException e){e.printStackTrace ();} .vIRz-S  
catch(Exception e){e.printStackTrace ();} &$#NV@  
} =i2]qj\  
' %rn-|)  
Z^J)]UL/  
private void processErrorCode(int nErrorCode) d7x6r3J$  
{ -- IewW  
System.err.println("Error Code : " + nErrorCode); lQt,(@7]  
} W>,D$  
AT2D+Hi=E  
xa !/.  
//停止文件下载 1-<?EOYaE  
public void siteStop() !wKNYe  
{ ?i!d00X  
bStop = true; >>;He7  
for(int i=0;i<nStartPos.length;i++) Y[m*  
fileSplitterFetch.splitterStop();  (tT%rj!  
%+;amRb  
@kba^z  
} Q'j00/K  
} &`-e; Xt  
//负责部分文件的抓取 yV6U<AP$3  
**FileSplitterFetch.java })q8{Qj!  
*/ /nt%VLms %  
package NetFox; !HW?/-\,O  
Y8fel2;  
!NKPy+v  
import java.io.*; [s%uE+``S  
import java.net.*; g(S4i%\  
|uRYejj#j  
 ZLf(m35  
public class FileSplitterFetch extends Thread { >{rD3X"d  
K!-iDaVI  
z_y@4B6>}  
String sURL; //File URL & ##JZ  
long nStartPos; //File Snippet Start Position Z^KWYe'w  
long nEndPos; //File Snippet End Position ,W_".aguX  
int nThreadID; //Thread's ID nA=E|$1  
boolean bDownOver = false; //Downing is over M{Vi4ehOq  
boolean bStop = false; //Stop identical 3XUsw1,[  
FileAccessI fileAccessI = null; //File Access interface 9IacZ  
N]|)O]/[  
lZ`@ }^&  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7L]Y.7>  
{ ^5FwYXAxi  
this.sURL = sURL; wqX!7rD/g)  
this.nStartPos = nStart; Ro2!$[P  
this.nEndPos = nEnd; =trLL+vGw'  
nThreadID = id; fCv.$5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _gCi@uXS3  
} Rp}Sm,w(  
Q[aBxy (  
.[6T7fdi  
public void run() COH>B1W@  
{ |4` ;G(ta  
while(nStartPos < nEndPos && !bStop) =feVT2*  
{ 'm/`= QX  
RNcnE1=  
_sCzee&uQ  
try{ mP_c-qD |  
URL url = new URL(sURL); iTCY $)J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P Qi=  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^c){N-G  
String sProperty = "bytes="+nStartPos+"-"; 8`WaUB%  
httpConnection.setRequestProperty("RANGE",sProperty); ^Uik{x  
Utility.log(sProperty); ^X:g C9  
'W~6-c9y  
SMA' VU  
InputStream input = httpConnection.getInputStream(); y"w`yl{_  
//logResponseHead(httpConnection);  '^,|8A2  
sz4;hSTy  
M-C>I;a  
byte[] b = new byte[1024]; }SS~uQ;8  
int nRead; 4zqO!nk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Z.U8d(  
{ <bh!wf6;  
nStartPos += fileAccessI.write(b,0,nRead); A$::|2~  
//if(nThreadID == 1) QY1|:(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PD:lI]:s  
} H4ancmy  
l9{.~]V  
a0&R! E;  
Utility.log("Thread " + nThreadID + " is over!"); s{0c.M  
bDownOver = true; Pbakw81!~  
//nPos = fileAccessI.write (b,0,nRead); A_|X54}w&  
} tE:6  
catch(Exception e){e.printStackTrace ();} mX@!O[f%9e  
} -JXCO <~k  
} l}9E0^AS  
5 r&n  
VCvFCyAz  
//打印回应的头信息 qW9~S0sl  
public void logResponseHead(HttpURLConnection con) PW"uPn  
{ "pQ) 5/e  
for(int i=1;;i++) 2zbV9Bhq  
{ x I(X+d``  
String header=con.getHeaderFieldKey(i);  dm{/  
if(header!=null) o/I`L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }(w9[(K  
Utility.log(header+" : "+con.getHeaderField(header)); tP|ox]  
else UiN6-{v<2  
break; 91}kBj  
} h@D!/PS  
} SfGl*2  
?w>-ya  
/jd.<r=_I  
public void splitterStop() 4cJka~  
{ `SG8w_  
bStop = true; (L !#2Jy  
}  *#sY-Gd  
)'axJ  
~x g#6%<=  
} f9?f!k  
^eCMATE  
?0'db  
/* )L$)qfQ~x  
**FileAccess.java 7;Vqr$9)  
*//文件访问(定位,写) 80Z'1'u0  
package NetFox; rLI );!^-  
import java.io.*; pXoT@[}  
n_P2l<F~/x  
&>3 AL,  
public class FileAccessI implements Serializable{ G!5~`v  
Tu}?Q. pKo  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }/.GB5Ej  
RandomAccessFile oSavedFile; [> LL  
long nPos; sx@ %3j  
FYX" q-Z  
*.A{p ;JC(  
public FileAccessI() throws IOException 3mLtnRX[m  
{ ]}>uvl^l  
this("",0); {7LNQGiJ  
} :Wd@Qy?;  
5HW'nhE  
g6 6SCr}  
public FileAccessI(String sName,long nPos) throws IOException U$=#yg2 :  
{ Ec l/2  
oSavedFile = new RandomAccessFile(sName,"rw"); )|E617g  
this.nPos = nPos; )o_Pnq9_  
oSavedFile.seek(nPos); 1'BC R  
} `z?h=&N  
6w4}4i  
[F}_Ime  
public synchronized int write(byte[] b,int nStart,int nLen) [IPXU9& Q  
{ 2#`9OLu8X  
int n = -1; cxn*!TwDs  
try{ !9vq"J~hz"  
oSavedFile.write(b,nStart,nLen); >4]y)df5  
n = nLen; [^ eQGv[S  
} T6I$7F  
catch(IOException e) raB', Vp  
{ SuFGIb7E  
e.printStackTrace (); ,!oR"b!  
} o$KW*aDp  
y}GFtRNG  
>A ?,[p`<  
return n; &a?k1R>  
} GVUZn//  
+9R@cUr  
bDT@E,cSi  
} y.Y;<UGu  
)6:1`&6  
Gq0`VHAn  
/* ]@hN&W(+x  
**SiteInfoBean.java 7~m[:Eg6[s  
*/ v)%0`%nSR  
package NetFox; tDn:B$*}W,  
1Y(NxC0P=g  
4)NbQ[  
public class SiteInfoBean { ,<!v!~Iy  
Vl%UT@D|  
(u-eL#@  
private String sSiteURL; //Site's URL ]lZ g }7h  
private String sFilePath; //Saved File's Path l3HfaCP6:  
private String sFileName; //Saved File's Name eR>|1s%^  
private int nSplitter; //Count of Splited Downloading File V&Q_i E  
fO t?2Bh  
Ln"D .gpq  
public SiteInfoBean() /uJ(&#87  
{//nSplitter的缺省值为5 ms`U,  
//default value of nSplitter is 5 BL1d= %2 R  
this("","","",5); ;U]Ym48  
} *dPG[ }  
QHgkfo  
(e _l1O?  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [SU;U['7  
{ kB-]SD#  
sSiteURL= sURL; .0?A0D?sP  
sFilePath = sPath;  {B7${AE  
sFileName = sName; uG=~k O  
this.nSplitter = nSpiltter; ~+CEek  
fRomP-S  
YWF Hv@  
} ,C}s8|@k  
i2l/y,UX  
$tB `dDj  
public String getSSiteURL() ;2[o>73F  
{ hkl9 EVO)  
return sSiteURL; HJjx!7h  
} =;~*YD(%/  
#R*7y%cO  
?(Ytc)   
public void setSSiteURL(String value) =+w!fy  
{ (Q}ByX  
sSiteURL = value; usR+ZQaA  
} c;.jo?RR2  
"2z&9`VIY  
a7n`(}?Y  
public String getSFilePath() 7[ZoUWx  
{ vE&K!k`  
return sFilePath; 9NeHN@D)  
} Y@ X>ejk"  
)LTX.Kg  
V)A7q9Bum  
public void setSFilePath(String value) r-$VPW  
{ /_1q)`NYy  
sFilePath = value; qFN`pe,  
} 8,-U`.  
d9q`IZqee  
!nL>Ly  
public String getSFileName() KpC!C9  
{ Of m0{c=  
return sFileName; @ )Nw>/; o  
} `wKd##v'@  
Af Y ]i  
U3~rtc*  
public void setSFileName(String value) W#kd[Wi  
{ `PZcL2~E  
sFileName = value; TlD^EJG  
} OM?FpRVU8  
F+)g!NQZ  
PFjh]/=  
public int getNSplitter() =HjC.h  
{ _o? I=UN2:  
return nSplitter; `t3w|%La}  
} LjCUkbzQF  
rqz48~\lJ  
,0f^>3&n>e  
public void setNSplitter(int nCount) W/<Lp+p  
{ 9D]bCi\  
nSplitter = nCount; S4VM(~,o  
} l'7' G$v  
} uc aa;zj  
>~jl0!2z@  
X3'd~!a)  
/* lJdrrR)wg  
**Utility.java ai"N;1/1O|  
*/ 8Y [4JXUK  
package NetFox; v^aI+p6  
9XmbHS[0V  
Rk#p zD  
public class Utility { QL:Qzr[  
%OOy90b2  
,*8)aZ1 k  
public Utility() gO#%*  W  
{ F},kfCFF  
j{YIVX  
# J^ >7v  
} {t|Q9&  
=!u]t &yv  
//线程睡眠 gts09{"}Y  
public static void sleep(int nSecond) hISYtNWjd"  
{ )j!%`g  
try{ Cz6bD$5  
Thread.sleep(nSecond); .>1vN+  
} ? (M$r\\  
catch(Exception e) E: Ul_m8  
{ e5(c,,/  
e.printStackTrace (); .|0$?w  
} ^%O$7*  
} =R*IOJ  
p-*{x  
//日志 =^z*p9ZB  
public static void log(String sMsg) *onVG5<  
{ ; W$.>*O  
System.err.println(sMsg); .E;}.X  
} Ld 0j!II(  
|Xmzq X%  
-Gjz+cRns  
public static void log(int sMsg) 4kR;K !@k  
{ Q)\[wYMt  
System.err.println(sMsg); 2V*;=cv~z  
} MAQ-'s@  
} Y$_^f*sFn  
,(f({l[J}  
'p)DJUwt  
/* ~5>TMIDiuR  
**TestMethod.java bnN&E?{hF1  
*/ >M^:x-mib  
package NetFox; >sQf{uL  
q#K0EAgC  
mR$0Ij/v  
public class TestMethod { |h6, .#n  
vhzz(UPUt  
h+}{FB 29  
public TestMethod() =&PO_t5)z  
{ ///xx/weblogic60b2_win.exe SNf~%B?`L  
try{ 58R.`5B  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /Mj|Px%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); iLNO}EUL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); O^8=Xj#}  
fileFetch.start(); (yoF  
} ZCA= n  
catch(Exception e){e.printStackTrace ();} @2`nBtk  
OW#G{#.6R  
";^_[n  
} 7Rd(,eWE@  
qDgy7kkQ  
goNDS5}  
public static void main(String[] args) 8:2Vib$  
{ uX6p^KNm5  
new TestMethod(); *VUJ);7k  
} U G4I @@=  
} IFW7MF9V  
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