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http断点续传简单实现(java)

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/* ,dBI=D'  
**SiteFileFetch.java FhGbQJ?[3  
*/ Q*: Ow]  
package NetFox; *F0N'*  
import java.io.*; pjFgIG2=9  
import java.net.*; B|v fkX2f  
d@hJ=-4  
16vfIUtb  
public class SiteFileFetch extends Thread { #x21e }Li  
K-ebAaiC  
z61 o6mb  
SiteInfoBean siteInfoBean = null; //文件信息Bean $G3P3y: [  
long[] nStartPos; //开始位置 h*LIS@&9C5  
long[] nEndPos; //结束位置 *?{)i~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $`%.Y&A  
long nFileLength; //文件长度 RS~oSoAE  
boolean bFirst = true; //是否第一次取文件 |UG)*t/  
boolean bStop = false; //停止标志 T[~X~dqwn"  
File tmpFile; //文件下载的临时信息 ^^#A9AM  
DataOutputStream output; //输出到文件的输出流 vs~*=d27Pf  
o=ex{g(3  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) i ^#R iCeo  
public SiteFileFetch(SiteInfoBean bean) throws IOException  UWI5 /R  
{ ?W()Do1tR  
siteInfoBean = bean; GfDA5v[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k4v[2y`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ',f[y:v;  
if(tmpFile.exists ()) U|=y&a2Rb  
{ *"@P2F&  
bFirst = false; I,D=ixK  
read_nPos(); eC?N>wHH  
} /1*\*<cs  
else _N6GV$Q  
{ ~&kV  
nStartPos = new long[bean.getNSplitter()]; 9V~yK?  
nEndPos = new long[bean.getNSplitter()]; OR3TRa XD  
} A.n1|Q#  
RW 5T}  
y}A-o_u@cD  
Liofv4![  
} f&:g{K  
qp Z ".  
eX\t]{\oC  
public void run() j.o)!S A  
{ 6*$N@>8&  
//获得文件长度 y^ohns5{  
//分割文件 AWw'pgTQX  
//实例FileSplitterFetch )jg3`I@  
//启动FileSplitterFetch线程 ,~v1NK*  
//等待子线程返回 5@Sb[za  
try{ b~r ?#2K  
if(bFirst) ~jgd92`{z  
{ ;Bm{_$hf=  
nFileLength = getFileSize(); IcB>Hg5  
if(nFileLength == -1) ,Fb#%r%  
{ R0Qp*&AL  
System.err.println("File Length is not known!"); 0/c4%+ Ln  
} !|D,cs  
else if(nFileLength == -2) $/Mk.(3'P  
{ ~34$D],D  
System.err.println("File is not access!"); gN*8 zui  
} g& {YHq^+  
else !)GPI?{^5  
{ \>+gZc]an  
for(int i=0;i<nStartPos.length;i++) =Oy,SX  
{ rS=6d6@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); B$)KZR(u  
} 7{6wNc  
for(int i=0;i<nEndPos.length-1;i++) grZN.zTO  
{ yt?# T #  
nEndPos = nStartPos[i+1]; ,W.O*vCA  
} Mf?4 `LM  
nEndPos[nEndPos.length-1] = nFileLength; d%WFgf}  
} >6Q-e$GS@  
} m#uutomi0  
BJqM=<nQ  
hSxf;>(d  
//启动子线程 17-K~ybc  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; mV-MJ$3r  
for(int i=0;i<nStartPos.length;i++) xMe[/7)4  
{ &4DWLI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <3i!{"}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gX[6WB"p  
nStartPos,nEndPos,i); y<)x`&pcD  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f+rBIE  
fileSplitterFetch.start(); #6JG#!W  
} /gxwp:&lY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Zvc{o8^z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'INdZ8j_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", cEe>Lyt  
nEndPos = " + nFileLength); xSw ^v6!2  
// fileSplitterFetch[nPos.length-1].start(); Ax&+UxQ0|  
+?%huJYK,  
W )\~T:Kn  
//等待子线程结束 X4jtti  
//int count = 0; #U^@)g6  
//是否结束while循环 X"yLo8y8$  
boolean breakWhile = false; <=WQs2  
)AnX[:y  
lE4.O  
while(!bStop) Y #KgaZ7N  
{ i),W1<A1  
write_nPos(); < d?O#(  
Utility.sleep(500); UtzW5{  
breakWhile = true; }z}oVc  
v=!]t=P)t  
 0N md*r  
for(int i=0;i<nStartPos.length;i++) K?) &8S  
{ @X|CubJ  
if(!fileSplitterFetch.bDownOver)  E;k'bz  
{ %|UCs8EFm  
breakWhile = false; < }G7#xg  
break; G"wy?  
} 0Y{A  
} yKi* 8N"e<  
if(breakWhile) ^dQ#\uy  
break; $cnIsyKWY  
60Y&)UR  
gz8<&*2  
//count++; ;'*"(F=D6  
//if(count>4) @Kp2l<P  
// siteStop(); ~qs 97'  
} 4\>Cnc{  
Q 1g@FsW&U  
M*|x,K=U  
System.err.println("文件下载结束!"); Ue! &Vm  
} 'RXh E  
catch(Exception e){e.printStackTrace ();} 9|fg\C  
} 5EM(3eY^q  
s~,Ypo?  
-|T.APxB  
//获得文件长度 SO9j/  
public long getFileSize() 2ACN5lyUS  
{ 2]hQ56Yv3  
int nFileLength = -1; ml\A)8O]j/  
try{ Tm qtj  
URL url = new URL(siteInfoBean.getSSiteURL()); ^As^hY^p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >HXT:0  
httpConnection.setRequestProperty("User-Agent","NetFox"); VD,g  
n)gzHch  
k68\ _NUL  
int responseCode=httpConnection.getResponseCode(); -b8Vz}Y  
if(responseCode>=400) CM_FF:<tn  
{ ;mu^WIj  
processErrorCode(responseCode); ^ 14U]<  
return -2; //-2 represent access is error o/ ozX4C  
} m\RU |Z  
s7[du_)  
GG-7YJ  
String sHeader; `;L>[\Xi  
JdF;*`_7*  
Y:XE4v/)@L  
for(int i=1;;i++) 1ve %xF  
{ D:4Iex9$F"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); unKi)v1  
//Utility.log(in.readLine()); nDhr;/"i  
sHeader=httpConnection.getHeaderFieldKey(i); NJRk##Z  
if(sHeader!=null) _SY4Q s`d  
{ +iY.YV  
if(sHeader.equals("Content-Length")) R.-2shOE'  
{ Kf/1;:^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); fYBmW')  
break; 07`hQn)Gc  
} 8>%:MS"  
} $hXhq*5|c  
else W1fEUVj  
break; @@M 2s(  
} JHC 6l  
} 7.`Fe g.  
catch(IOException e){e.printStackTrace ();} ]3nka$wA*  
catch(Exception e){e.printStackTrace ();} .5 Sw  
`7[z%cuK  
yY+)IU.  
Utility.log(nFileLength); |uf{:U)  
xM"k qRZ  
>)\x\e  
return nFileLength; m^I+>Bp/:  
} ZCVwQ#Xe+  
)RG@D\t,  
%5Q5xw]w3  
//保存下载信息(文件指针位置) p=sL KnLmZ  
private void write_nPos() GgwO>[T  
{ Sc#B -4m  
try{ =:A hg 9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); O eLM*Zi  
output.writeInt(nStartPos.length); d^p af  
for(int i=0;i<nStartPos.length;i++) o."k7fLB  
{ 845a%A$  
// output.writeLong(nPos); kV9S+ME  
output.writeLong(fileSplitterFetch.nStartPos); : p %G+q2  
output.writeLong(fileSplitterFetch.nEndPos); 2O;Lw@W  
} 8` ~M$5!  
output.close(); uyZ  
} P@lDhzd  
catch(IOException e){e.printStackTrace ();} O|wu;1pQ  
catch(Exception e){e.printStackTrace ();} )IQ5Qu  
} bS7rG$n [  
>ka*-8?  
~QzUQYG*  
//读取保存的下载信息(文件指针位置) qRi;[`  
private void read_nPos() jd ]$U_U(  
{ P5-1z&9O  
try{ 0se0AcrW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ts|dk%  
int nCount = input.readInt(); A8tzIh8  
nStartPos = new long[nCount]; YD>5zV%!D  
nEndPos = new long[nCount]; 3h N?l :/b  
for(int i=0;i<nStartPos.length;i++) Zcst$Aro  
{ :buH\LB*P  
nStartPos = input.readLong(); 17kh6(X  
nEndPos = input.readLong();  KT'Ebb]  
} K=lm9K  
input.close(); PY.4J4nn|  
} IY_u|7d  
catch(IOException e){e.printStackTrace ();} ^K[WFiN}  
catch(Exception e){e.printStackTrace ();} k+qxx5{  
} v_=xN^R  
}#'I,?_k  
f 0"N  
private void processErrorCode(int nErrorCode) LelCjC{`1  
{ ;6+e!h'1  
System.err.println("Error Code : " + nErrorCode); =T7lv%u  
} P}kBqMM  
5@c/,6l  
(h&XtFul}  
//停止文件下载 #WE"nh9f|z  
public void siteStop() <7  
{ ct o+W}k  
bStop = true; 3QM;K^$  
for(int i=0;i<nStartPos.length;i++) w2 %u;D%  
fileSplitterFetch.splitterStop(); fyHFfPEE  
}enS'Fpf`  
/w[B,_ZKTk  
} o}^/K m+t  
} @bfW-\ I  
//负责部分文件的抓取 R{6~7<m.  
**FileSplitterFetch.java Ei$?]~ &  
*/ ppYIVI  
package NetFox; \Dn47V{7-  
Q5K<ECoPk  
`3wzOMgJ  
import java.io.*; t?&@bs5~g  
import java.net.*; *,x-}%X  
d;:H#F+ (  
MawWgd*  
public class FileSplitterFetch extends Thread { XHN*'@ 77;  
J)kH$!csi  
8)KA {gN}  
String sURL; //File URL Nj5V" c  
long nStartPos; //File Snippet Start Position 0XgJCvMcB  
long nEndPos; //File Snippet End Position +O]jklS4H  
int nThreadID; //Thread's ID J~jxmh  
boolean bDownOver = false; //Downing is over 322)r$!"  
boolean bStop = false; //Stop identical N"',  
FileAccessI fileAccessI = null; //File Access interface 1&7~.S;km  
-=;V*;  
uDe%M  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException . W7Z pV  
{ fCMFPhF  
this.sURL = sURL; U<|hIv-&  
this.nStartPos = nStart; KzgW+6*G  
this.nEndPos = nEnd; bh Nqj  
nThreadID = id; f52*s#4}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h=a-~= 8  
} 9>QGsf.3  
Gl!fT1zh0  
l^~E+F~  
public void run() \jR('5DcB  
{ }Cs. Hm0P  
while(nStartPos < nEndPos && !bStop) r}>q*yx:  
{ ~ k(4eRq  
3AQu\4+A  
Q|$?d4La8  
try{ t%k1=Ow5i  
URL url = new URL(sURL); %@q/OVnM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 31cC*  
httpConnection.setRequestProperty("User-Agent","NetFox"); %)t9b@c!}  
String sProperty = "bytes="+nStartPos+"-"; J 7/)XS  
httpConnection.setRequestProperty("RANGE",sProperty); NT1"?Thx|  
Utility.log(sProperty); isF jJPe  
g %ZKn  
bjq+x:>  
InputStream input = httpConnection.getInputStream(); \h{M\bSIEa  
//logResponseHead(httpConnection); U@'F9UB`  
3oo Tn-`{  
f+c<|"we  
byte[] b = new byte[1024]; Le?yzf  
int nRead; SWq5=h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) s.uw,x  
{ dv7IHUFf  
nStartPos += fileAccessI.write(b,0,nRead); l<DpcLX  
//if(nThreadID == 1) H?H(=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bP+b~!3  
} ;$FpxurX  
hQFF%xl  
 ?|$IZ9  
Utility.log("Thread " + nThreadID + " is over!"); `i"7; _HoV  
bDownOver = true; ^q@6((O  
//nPos = fileAccessI.write (b,0,nRead); bMCy=5  
} ^Gt9.  
catch(Exception e){e.printStackTrace ();} 3;E,B7,mQ  
} fGf C[DuY  
} \9Yc2$dY  
GEd JB=  
^#0k\f>_  
//打印回应的头信息 h%=>iQ%enc  
public void logResponseHead(HttpURLConnection con) Shag4-*@hi  
{ BKJwM'~  
for(int i=1;;i++) J]"IT*-Ht  
{ Cju%CE3a  
String header=con.getHeaderFieldKey(i); Jx-dWfe  
if(header!=null) ", Ge:\TR=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); USrBi[_ci\  
Utility.log(header+" : "+con.getHeaderField(header)); l,w$!FnmR  
else 9$iDK$%  
break; Vmb `%k20'  
} p$+.]  
} naaww  
IPTEOA<M[  
q\I2lZ  
public void splitterStop() 9FKowF_8  
{ PKK18E}{%^  
bStop = true; jn:9Cr,o;g  
} qiyX{J7Z  
OtsW>L@ O(  
}$wWX}@  
} ==^9_a^  
[m+):q^  
QKAt%"1&  
/* ?*K{1Ghf  
**FileAccess.java W&'[Xj  
*//文件访问(定位,写) Up*.z\|'y  
package NetFox; MmL)CT  
import java.io.*; z{uRq A G  
YB?5s`vr9d  
v "Yo  
public class FileAccessI implements Serializable{ id=:J7!QU  
+ m+v1(@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (imaL,M-D  
RandomAccessFile oSavedFile; m,1Hlp  
long nPos; W6 y-~  
'U|Tye i?  
O&vE 5%x  
public FileAccessI() throws IOException R>#BJ^>=  
{ '^# =,+ A  
this("",0); V!XT=Ou?6  
} fa:V8xa  
qHtonJc  
x<lY&KQ0  
public FileAccessI(String sName,long nPos) throws IOException XqxmvN  
{ [>#@?@x`P  
oSavedFile = new RandomAccessFile(sName,"rw"); l+!eC lM%  
this.nPos = nPos; fk)5TPc^  
oSavedFile.seek(nPos); EW}7T3g  
}  tOEY|  
)B1gX>J\8  
or)v:4PXW  
public synchronized int write(byte[] b,int nStart,int nLen) s/cclFji]  
{ Rg,]d u u?  
int n = -1; Q}qw` L1  
try{ ;+6TZqklQ  
oSavedFile.write(b,nStart,nLen); k&M9Hn2  
n = nLen; g)/#gyT4Y  
} >$ok3-tuU  
catch(IOException e) vk>EFm8l  
{ QswbIP/>:'  
e.printStackTrace (); eX0ASI9  
}  8-.jf  
F&[MyXU4  
Mb +  
return n; M>m+VsJV  
} |Js?@  
x4 .Y&Wq#  
C#3K.0a  
} <JkmJ/X  
8-clL\bm  
Qi?xx')  
/*  )o\U4t  
**SiteInfoBean.java J\fu6Ti  
*/ z!> H^v  
package NetFox; AhauNS^"{R  
_ giZ'&l!  
Rk(2|I  
public class SiteInfoBean { y%NZ(Y,v  
b xFDB^  
{DVu* %|  
private String sSiteURL; //Site's URL oD?c]}3  
private String sFilePath; //Saved File's Path Vh o3I[C  
private String sFileName; //Saved File's Name :0o,pndU  
private int nSplitter; //Count of Splited Downloading File DwBKqhu  
ZBcT@hxm  
\Ng|bWR>LQ  
public SiteInfoBean() XaH%i~}3  
{//nSplitter的缺省值为5 ;c;5O@R}3  
//default value of nSplitter is 5 rV6SN.  
this("","","",5); ZlEH3-Zv  
} \&#pJBBG  
SIr^\iiOB  
klON6<w  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) VzZ'W[/7)B  
{ sn=_-uoU  
sSiteURL= sURL; HAOl&\)7"_  
sFilePath = sPath; ~4{|  
sFileName = sName; ^9wQl!e ob  
this.nSplitter = nSpiltter; #G`UR  
W:V:Ej7 h  
;wF 0s  
} <~ 9a3c?  
_Vl22'wl  
b0n " J`  
public String getSSiteURL() Cg4l*"_  
{ OqNtTk+  
return sSiteURL; ^;[|,:8f7L  
} 64jFbbd-/  
fO'"UI  
#eKg!]4-R  
public void setSSiteURL(String value) `L#`WC@[o  
{ FvTc{"w /  
sSiteURL = value; 20Rj Rd  
} QW[ gDc  
X6`F<H`  
\u@*FTS  
public String getSFilePath() /6@~XO) w  
{ .{}=!>U2  
return sFilePath; (|kcSnF0  
} @ UgZZ  
|MEu"pY)  
I(2qXOG  
public void setSFilePath(String value) |?=a84n1l  
{ +^0Q~>=VD  
sFilePath = value; IA$)E  
} `$hna{e^n  
d=J$H<  
S( nZ]QEG  
public String getSFileName() ,KO_h{mI<  
{ 5OS|Vp||b  
return sFileName; q5D_bm7,3  
} F4T}HY>nZ  
ja1WI  
F[HMX4  
public void setSFileName(String value) dd=' ;%?  
{ [@RJ2q$  
sFileName = value; ]u\K}n6[q  
} )4@La&  
=:~%$5[[  
p(J,fus  
public int getNSplitter() ud}B#{6  
{ a9<&|L <  
return nSplitter; b{WEux{)  
} |#x]FNg  
h%0hryGB  
`EjPy>kM  
public void setNSplitter(int nCount) }% m:^*@$9  
{ iR`c/  
nSplitter = nCount; N9s ,..  
} _t+.I9kQ  
} Ev'Bm Dk  
EoOB0zo}Y+  
dDeImSeV  
/* iCK p"(kf  
**Utility.java 2:>|zmh_  
*/ hrt ]Qn&  
package NetFox; .JG>/+  
n,.ZLuBEX  
<l,Kg 'v  
public class Utility { hj8S#  
%%=PpKYtSD  
uk\-"dS  
public Utility() R"0fZENTG  
{ q_sQC5:s  
T9,T'y>BD  
w&F/P]1  
} 6)QJms  
VXpbmg!{S  
//线程睡眠 qit D{;  
public static void sleep(int nSecond) q!5 *) nw"  
{ >We:g Kxr  
try{ GOx+%`.R\  
Thread.sleep(nSecond); 3Xun>ZQ-  
} q')MKR*  
catch(Exception e)  3e<FlH{  
{ L;n2,b  
e.printStackTrace (); J:{$\m'  
} D`t }V  
} 2!Mwui;%  
P [.BK  
//日志 |kUxTe  
public static void log(String sMsg) d]v4`nc  
{ N<xf=a+j  
System.err.println(sMsg); o9l =Q  
} !+E|{Zj  
~}c`r4  
2(, `9  
public static void log(int sMsg) kg>Ymo.  
{ | Q Y_ci  
System.err.println(sMsg); 3M nm2*\  
} \Lz2"JI  
} >UP{= `  
B"-gK20vY  
:uAW  
/* s[V$f vW  
**TestMethod.java <By6%<JTn  
*/ p8>.Q/4  
package NetFox; ?D].Za^km  
Pgy&/-u  
MZ(TST"  
public class TestMethod { q+MV@8w  
 M>mk=-l  
v}=3  
public TestMethod() reyN5n~4U  
{ ///xx/weblogic60b2_win.exe {\OIowa  
try{ @$5GxIw<l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); e$k ]z HlQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `Z3Qx~f x  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0L34)W  
fileFetch.start(); hrwQh2sm  
} YU89m7cc'  
catch(Exception e){e.printStackTrace ();} {[~ !6&2(k  
6,"fH{Bd  
^lqcF.  
} }`oe<|  
[TZlvX(E  
Xwg|fr+p  
public static void main(String[] args) FkdG@7Xf  
{ @quNVx(y  
new TestMethod(); 58H[sM4>  
} w1J&c'-  
} wff&ci28  
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