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http断点续传简单实现(java)

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/* @Z=wE3T@  
**SiteFileFetch.java ".M:`BoW4  
*/ ]+lF=kkc %  
package NetFox; Bt6xV<jD  
import java.io.*; [)iN)$Mv  
import java.net.*; >Qk97we'9  
p|s2G~0<  
f\=6I3z  
public class SiteFileFetch extends Thread { &z QWIv  
W+/2c4$F3  
h {H]xe[Q  
SiteInfoBean siteInfoBean = null; //文件信息Bean 85 Dm8~  
long[] nStartPos; //开始位置 43F^J%G  
long[] nEndPos; //结束位置 :1NYpsd.i  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 X_!$Pk7ma  
long nFileLength; //文件长度 aLHrl6"  
boolean bFirst = true; //是否第一次取文件 hvL6zCi  
boolean bStop = false; //停止标志 @QX4 \  
File tmpFile; //文件下载的临时信息 +ruj  
DataOutputStream output; //输出到文件的输出流 S}O5l}E  
'1lx{U zD  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 65t[vi*C  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,`+Bs&S 8  
{ %27G2^1  
siteInfoBean = bean; ?Cc$]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8W{ g  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); I>!|3ElT  
if(tmpFile.exists ()) L% zuI& q  
{ -/1d&  
bFirst = false; *eMLbU7  
read_nPos(); o` 2 5  
} 75PS^5T,  
else ?9CIWpGjU  
{ Km%8Yw0+  
nStartPos = new long[bean.getNSplitter()]; cx<h_  
nEndPos = new long[bean.getNSplitter()]; Aw5K3@Ltz  
} 9.jG\i  
;Xz(B4N~o  
;,R[]B01u  
9B& }7kk  
} t<8z08  
5N Fq7&rJ6  
&#$2;-q8+  
public void run() ;%M2x5  
{ r';Hxa '  
//获得文件长度 D~XU `;~u  
//分割文件 EC0zH#N  
//实例FileSplitterFetch rUGZjLIGqz  
//启动FileSplitterFetch线程 tvv[$ b&  
//等待子线程返回 3{I=.mUUm  
try{ se }pdL}  
if(bFirst)  `NTM%# w  
{ |)~Ex 9%ev  
nFileLength = getFileSize(); oA5<[&~<  
if(nFileLength == -1) -Cg`x=G;z  
{ ?=TL2"L  
System.err.println("File Length is not known!"); I=Gr^\x=  
} ,M| QN*  
else if(nFileLength == -2) VZAuUw+M  
{ A&x ab  
System.err.println("File is not access!"); !k4 }v'=  
} p`shY yE  
else [P(rY  
{ >aNbp  
for(int i=0;i<nStartPos.length;i++) };4pZceV  
{ `M towXj  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u Zo]8mV  
} @&/s~3  
for(int i=0;i<nEndPos.length-1;i++) qiF@7i  
{ GGYX!=]~  
nEndPos = nStartPos[i+1]; /F\>Z]  
} kxt\{iy4  
nEndPos[nEndPos.length-1] = nFileLength; HQ ELK  
} l"2^S6vU  
} WsG"x>1n  
tg4LE?nv  
fU\k?'x_  
//启动子线程 TyxU6<>4J4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [flu |v  
for(int i=0;i<nStartPos.length;i++) n23%[#,r  
{ yf0vR%,\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ::^qy^n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), iX0]g45o  
nStartPos,nEndPos,i); lo IL{2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]{q- Y<{"  
fileSplitterFetch.start(); x9FLr}e  
} wdN>KS2!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OX#eLco  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); p 02nd.R6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", j\i;'t}8g  
nEndPos = " + nFileLength); F)[XIY&2/  
// fileSplitterFetch[nPos.length-1].start(); r_!{!i3B  
-+j9X;h:  
0{^l2?mgSb  
//等待子线程结束 yhw:xg_;Kz  
//int count = 0; 02]8|B(E90  
//是否结束while循环 /h}wM6pg  
boolean breakWhile = false; Y%n{`9=  
46Y7HTwE  
u`L!za7fi  
while(!bStop) &CxyP_  
{ &"~,V6,q  
write_nPos(); HlOAo:8'  
Utility.sleep(500); #2ZrdD"5kQ  
breakWhile = true; n;S0fg  
cAsSN.HFS  
1%]{0P0?[  
for(int i=0;i<nStartPos.length;i++) 4X(1   
{ vMW-gk  
if(!fileSplitterFetch.bDownOver) n{qa]3  
{ :3E8`q~c1  
breakWhile = false; U:etcnb4w>  
break; ino7!T`  
} )+Y\NO?O  
} R"8})a gw  
if(breakWhile) Wj  
break; m\}\RnZu  
.LGkr@P  
)P(d66yq'u  
//count++; q6m87O9  
//if(count>4) 7y)|^4X2  
// siteStop(); fO^EMy\  
} v0H>iKh7  
r,Y/4(.c7U  
+gD)Yd  
System.err.println("文件下载结束!"); b/D9P~cE  
} &s6(3k  
catch(Exception e){e.printStackTrace ();} *fuGVA  
} A]~iuUHm  
[u9S+:7"  
+2k|g2  
//获得文件长度 61eKGcjs:  
public long getFileSize() ^JF_;~C  
{ gYH:EuY,  
int nFileLength = -1; s_Ge22BZ  
try{ |0vHy7CE  
URL url = new URL(siteInfoBean.getSSiteURL()); 'mY,>#sT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); aBA#\eV  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~M9 n<kmE  
nF!_q;+Vp  
zf!\wY"`  
int responseCode=httpConnection.getResponseCode(); ;6 &=]I  
if(responseCode>=400) hz~CW-47  
{ nD?M;XN  
processErrorCode(responseCode); ^2?O+ =,F  
return -2; //-2 represent access is error kvO`]>#;$?  
} Wp9 2sm+  
@*`UOgP7  
/o06hy  
String sHeader; $nd-[xV  
51(`wo>LS  
!+26a*P  
for(int i=1;;i++) 'r?HL;,q  
{ t%YX-@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); E,yzy[gl  
//Utility.log(in.readLine()); |9i/)LRXe  
sHeader=httpConnection.getHeaderFieldKey(i); z&yb_A:>  
if(sHeader!=null) !&:W1Jkp(  
{ 8!fAv$g0  
if(sHeader.equals("Content-Length")) G|Yp <W%o  
{ :>-sITeY  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); CH_Dat >  
break; G`JwAy r'  
} iKEKk\j-w  
} 2,QApW_Y  
else '  ^L  
break; K}*p(1$u  
} 0~L 8yMM  
} $8ww]}K  
catch(IOException e){e.printStackTrace ();} Q\>SF  
catch(Exception e){e.printStackTrace ();} cM'[;u  
d~bH!P  
S$_Ts1Ge6  
Utility.log(nFileLength); J3}C T  
\]:NOmI^'  
Fu$Gl$qV?%  
return nFileLength; nsw8[pk  
} n_ NG~ /x  
]be2jQx3  
V`&*%xgGR  
//保存下载信息(文件指针位置) P##(V!YR  
private void write_nPos() hnL gsz  
{ 2X |jq4  
try{ 7Z:l;%]K  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Evgq}3  
output.writeInt(nStartPos.length); +A3\Hj&W  
for(int i=0;i<nStartPos.length;i++) E0%Y%PQ**{  
{ "YU~QOGx@  
// output.writeLong(nPos); FrM~6A_  
output.writeLong(fileSplitterFetch.nStartPos); (dnc7KrM  
output.writeLong(fileSplitterFetch.nEndPos); y/*Tvb #TJ  
} eeR@p$4i  
output.close(); MBrVh6z>  
} }(I DPaJ  
catch(IOException e){e.printStackTrace ();} (j Q6~1  
catch(Exception e){e.printStackTrace ();} e~[z]GLO%  
} otVdx&%]  
,'DrFlI  
f;dU72]q+  
//读取保存的下载信息(文件指针位置) qCT\rZU  
private void read_nPos() }n8;A;axi  
{ k"-#ox!  
try{ m8A1^ R  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); TTak[e&j3  
int nCount = input.readInt(); nezbmpL4  
nStartPos = new long[nCount]; UC$+&&rO  
nEndPos = new long[nCount]; T1[ZrY'0  
for(int i=0;i<nStartPos.length;i++) w:(7fu=  
{ J~`%Nj5>  
nStartPos = input.readLong(); 3`8xh 9O  
nEndPos = input.readLong(); wA&)y>n-  
} HBGA lZ  
input.close(); LZ dNG\-  
} hvZR4|k>  
catch(IOException e){e.printStackTrace ();} 7OHw/-j\  
catch(Exception e){e.printStackTrace ();} 4'| :SyOm  
} xM,(|p(  
p[:%Ck"$7  
a$& 6a   
private void processErrorCode(int nErrorCode) ?MB nnyo6  
{ L#b Q`t  
System.err.println("Error Code : " + nErrorCode); (fb\A6  
} $o H,:x?}  
Ux]@p rAq  
^<+heX  
//停止文件下载 =LA@E&,j  
public void siteStop() 8"^TWzg}L  
{ uS,$P34^oy  
bStop = true; T+!kRigN~P  
for(int i=0;i<nStartPos.length;i++) i|'t!3I^m  
fileSplitterFetch.splitterStop(); =1Jo-!{{  
>Sah\u`  
x*)O<K  
} W{aNS@1  
} A[a+,TN {  
//负责部分文件的抓取 . %7A7a  
**FileSplitterFetch.java 3/05ee;|  
*/ @kymL8"2w  
package NetFox; NE"fyX`  
]aL}&GlHt  
4F!d V;"Z(  
import java.io.*; {*Pp^ r  
import java.net.*; =<xbE;,0  
!CKUkoX  
1fZ:^|\  
public class FileSplitterFetch extends Thread { wYG0*!Vj  
L~~Yh{<  
l[k$O$jo  
String sURL; //File URL ~yN,FpD  
long nStartPos; //File Snippet Start Position ;wrgpP3  
long nEndPos; //File Snippet End Position YvX I  
int nThreadID; //Thread's ID *6tN o-)^  
boolean bDownOver = false; //Downing is over 6Tnzg`0I  
boolean bStop = false; //Stop identical UtN>6$u  
FileAccessI fileAccessI = null; //File Access interface R3A^VE;qP  
(z7#KJ1+Aw  
@35 shLs  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,vPF=wq  
{ lH.2H  
this.sURL = sURL; K2 2Xo<3  
this.nStartPos = nStart; y rk#)@/m  
this.nEndPos = nEnd; 2Fi*)\{  
nThreadID = id; $!Tw`O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 wQT'~'kL  
} stPCw$@  
FQ%mNowuj  
~@lNBF  
public void run() *b EsWeP  
{ nmr>Aj8[  
while(nStartPos < nEndPos && !bStop) CCV~nf  
{ M %~kh"  
;H lv  
\BL9}5y  
try{ e^yB9b  
URL url = new URL(sURL); +zsya4r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eAMT72_  
httpConnection.setRequestProperty("User-Agent","NetFox"); @d\F; o<  
String sProperty = "bytes="+nStartPos+"-"; I?QKd@  
httpConnection.setRequestProperty("RANGE",sProperty); @zbXG_J  
Utility.log(sProperty); (&(f`c@I  
a0R]hENC  
@_{"ho  
InputStream input = httpConnection.getInputStream(); fvD wg  
//logResponseHead(httpConnection); c+JlM1p@  
ry'(m M  
!r<7]nwV  
byte[] b = new byte[1024]; J5k%  
int nRead; scdT/|(U$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) E' Bt1 u  
{ 5WUrRQ?E  
nStartPos += fileAccessI.write(b,0,nRead); tz,FK;8  
//if(nThreadID == 1) {Fj`'0Xu;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (rJvE*  
} {8' 5  
c\Dv3bF  
> L%%B-  
Utility.log("Thread " + nThreadID + " is over!"); ]arP6 iN+  
bDownOver = true; i+;E uHf  
//nPos = fileAccessI.write (b,0,nRead); )l=j,4nn  
} ?Rdi"{.wI  
catch(Exception e){e.printStackTrace ();} .NKN2  
} y ;;@T X  
} yC[}gHv  
<6@Db$-  
>2a~hW|,  
//打印回应的头信息 /W9=7&R0  
public void logResponseHead(HttpURLConnection con) sdb#K?l  
{ \21!NPXH2  
for(int i=1;;i++) Z1Wra-g  
{ -a3C3!!  
String header=con.getHeaderFieldKey(i); Rh=h{O  
if(header!=null) y3x_B@}BY  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4 QWHGh"  
Utility.log(header+" : "+con.getHeaderField(header)); 8:f( PN  
else MStaP;|  
break; HkrNt/]  
} V{][{5SR  
} j0J6ySlY  
C-8@elZ1  
8W{R&Z7aL  
public void splitterStop() L(.5:&Y=`  
{ -{dw Ll_  
bStop = true; s^cHR1^  
} hQ9VcS6=gD  
qg_=5s  
m 9r X  
} IMj{n.y4  
B9]KC i  
7>#74oy  
/* d2pVO]l YZ  
**FileAccess.java >6c{CYuT  
*//文件访问(定位,写) ;e+ErN`a.~  
package NetFox; GE|V^_|i  
import java.io.*; p?5zwdX+`  
'2eggX%  
./u3z|q1  
public class FileAccessI implements Serializable{ % _N-:.S  
|1#*`2j\=9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =m UtBD.;  
RandomAccessFile oSavedFile; \]zH M.E1  
long nPos; d+8Sypv^4*  
F8q|$[nH  
XLB7 E  
public FileAccessI() throws IOException HZ/e^"cpM  
{ L:7%Wdyh  
this("",0); nBR4j?':i  
} 5-*/wKjLz  
ol-U%J  
J%{>I   
public FileAccessI(String sName,long nPos) throws IOException *&XOzaVU  
{ i!(u4wTFF  
oSavedFile = new RandomAccessFile(sName,"rw"); I=0`xF|4K-  
this.nPos = nPos; fTMn  
oSavedFile.seek(nPos); V3 2F  
} Nzf tc  
05Ak[OOU>  
U&GSMjqg  
public synchronized int write(byte[] b,int nStart,int nLen) 1GE[*$vuq  
{ RGsgT^  
int n = -1; 1 Qln|b8<  
try{ Ko: <@h  
oSavedFile.write(b,nStart,nLen); *jM]:GpyoU  
n = nLen; ]De<'x}  
} PKJw%.-  
catch(IOException e) wt]onve}%  
{ KSz;D+L \  
e.printStackTrace (); lxf+$Z`~:  
} vhvFBx0  
g=n{G@*N  
k..AP<hH  
return n; a]]eQ(xQ  
} T\q:  
]Q$Sei5  
JV ydTvc  
} |h%=a8  
zncKd{Q\tP  
TXdo,DPv7  
/* 42M_  %l_  
**SiteInfoBean.java 0Xb,ne 7  
*/ %tB7 &%ut  
package NetFox; tTOBKA89  
AO, o|,#4F  
:er(YWF:  
public class SiteInfoBean { agt/;>q\~  
/g$G G9  
H-\Ym}BGu  
private String sSiteURL; //Site's URL uP G\1  
private String sFilePath; //Saved File's Path 0 30LT$&!  
private String sFileName; //Saved File's Name o%7-<\qS  
private int nSplitter; //Count of Splited Downloading File y 4U|~\]  
|M`'   
e>6|# d  
public SiteInfoBean() JR8|!Of@B  
{//nSplitter的缺省值为5 JkhWLQ>o  
//default value of nSplitter is 5 _B>'07D0  
this("","","",5); 'Lq+ONX5  
} auga`*  
aq)g&.dw?  
s_  t/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {n|ah{_p|  
{ yts@cd`$  
sSiteURL= sURL; elAWQEu s  
sFilePath = sPath; %N)B8A9kh  
sFileName = sName; "4\k1H"_  
this.nSplitter = nSpiltter; <rtKPlb//  
/5)*epF+  
9dq"x[  
} BBM[Fy37!}  
r1}^\C  
?r KbL^2  
public String getSSiteURL() &#L C'  
{ D6A u)1y=&  
return sSiteURL; vhPlH0  
} VcGl8~#9  
4j~q,# $LW  
V:w%5'^3  
public void setSSiteURL(String value) tPl 4'tW_  
{ 0KnL{Cj   
sSiteURL = value; <4+P37^ ~  
} 9v_s_QkL2  
~v%6*9  
 tPQ|znB|  
public String getSFilePath() XHekz6_  
{ QuqznYSY{  
return sFilePath; lhHH|~t0  
} 5]>*0#C S  
p;>A:i  
wn.~Dx  
public void setSFilePath(String value) ]R_R`X?  
{ /1MmOB  
sFilePath = value; gYhY1Mym  
} N2O *g`YC  
K_;vqi^1^&  
i}VF$XN  
public String getSFileName() `wXK&R<`  
{ :ZM9lBYh  
return sFileName; iqvLu{  
} I )rO|  
&1$d`>fn  
~f h  
public void setSFileName(String value) 1ZI1+TDH  
{ B W<Dmn  
sFileName = value; sq!$+=1-X  
} C3}:DIn"w  
$DoR@2 ~y  
#B;P4n3  
public int getNSplitter() !l9{R8m>eJ  
{ f`n4'dG  
return nSplitter; I.n,TJoz4J  
} $Z:O&sD{  
C`hdj/!A  
x~V[}4E%>  
public void setNSplitter(int nCount) ;=y"Z^  
{ ,WRm{ v0f^  
nSplitter = nCount; UGSZg|&6#*  
} 2#>;cn\  
} c_3B:F7  
VHxBs  
Am<5J,<uy  
/* B?! L~J@p  
**Utility.java C^L+R7  
*/ e9o\qEm   
package NetFox; <rBW6o7  
e$Ksn_wEq  
!;eE7xn&  
public class Utility { F\ B/q  
?{ N,&d  
(`1i o  
public Utility() >v]^nJl  
{ x4WCAqi/2  
$G".PWc  
1&|]8=pG7  
} F\m^slsu7=  
:W.H#@'(  
//线程睡眠 }bb,Iib  
public static void sleep(int nSecond) 3vY-;&  
{ Lc{AB!Br  
try{ 2_q/<8t  
Thread.sleep(nSecond); 'Aq^z%|  
} MgXZN{  
catch(Exception e) x3q^}sj%  
{ ]SQ+r*a  
e.printStackTrace (); \Y4(+t=4  
} 7hHID>,o9%  
} "wgPPop  
"t0^4=c+7  
//日志 1SExl U  
public static void log(String sMsg) Db|f"3rq?  
{ {KG}m'lx  
System.err.println(sMsg); \n{# r`T  
} =-r"@2HBq  
2 R\K!e  
K(+=V)'Dz  
public static void log(int sMsg) \ lbH   
{ %Psg53N  
System.err.println(sMsg); 1aAOT6h  
} ),x0G*oebj  
} LeCc`x,5  
ctP+ECH  
jr` swyg  
/* &]TniQH  
**TestMethod.java \rr"EAk]  
*/ QRju9x  
package NetFox; JN8Rh  
|Yli~Qx  
n*\o. :f  
public class TestMethod { ntIR#fB  
e|tx`yA  
HM% +Y47a  
public TestMethod() RvR.t"8  
{ ///xx/weblogic60b2_win.exe PhAfEsD  
try{ n*[ZS[I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kX L0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Mi.#x_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); n.l#(`($4  
fileFetch.start(); 2bCfY\k  
} q7CLxv &QG  
catch(Exception e){e.printStackTrace ();} }XUL\6U  
LVUA"'6V  
f/dJRcDl<  
} ozY$}|sjDT  
'-"[>`[q  
Tf#Op v)  
public static void main(String[] args) uihH")Mo  
{ kI"9T`owR  
new TestMethod(); jG ouwta  
} Kb ]}p  
} ICz:>4M-dn  
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