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http断点续传简单实现(java)

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/* z0*_^MH  
**SiteFileFetch.java Y> Wu  
*/ 7=OQ8IM !  
package NetFox; H4!+q:<  
import java.io.*; G 0;XaL:  
import java.net.*; _}VloiY  
)V:]g\t  
pd8Nke  
public class SiteFileFetch extends Thread { 'ao"9-c  
s)2fG\1  
{aC!~qR  
SiteInfoBean siteInfoBean = null; //文件信息Bean -O!Zxg5x  
long[] nStartPos; //开始位置 y>|{YWbp?  
long[] nEndPos; //结束位置  \qR %%S  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ADk8{L{UU  
long nFileLength; //文件长度 H0R&2#YD  
boolean bFirst = true; //是否第一次取文件 aKJQm '9Ks  
boolean bStop = false; //停止标志 D HT&,=  
File tmpFile; //文件下载的临时信息 TdGnf   
DataOutputStream output; //输出到文件的输出流 BQ2wnGc  
BC;:  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ,b;{emX h  
public SiteFileFetch(SiteInfoBean bean) throws IOException { e5/+W  
{ tP%{P"g3^  
siteInfoBean = bean; -cm$[,b6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); g{9+O7q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -,{-bi  
if(tmpFile.exists ()) ]B]*/  
{ ]$\|ktY!  
bFirst = false; x5WW--YR+  
read_nPos(); 4[-*~C|W5  
} p6XtTx  
else xvSuPP4 m  
{ &gE 75B  
nStartPos = new long[bean.getNSplitter()]; (?! ,p^  
nEndPos = new long[bean.getNSplitter()]; "a/ Q%.P  
} u@%r  
BEgV^\u  
:C8$Xi_i}  
"y<?Q}1  
} $Qy7G{XJ[^  
d@G}~&.|  
rf%7b8[v  
public void run() -}6xoF?  
{ b (I2m  
//获得文件长度 3#45m+D  
//分割文件 e=QK}gzX  
//实例FileSplitterFetch uH;-z_Wpn!  
//启动FileSplitterFetch线程 D'hW|  
//等待子线程返回 N#_GJSG_|  
try{ V)i5=bHC  
if(bFirst) Z0>DNmH*  
{ \Ro^*4B  
nFileLength = getFileSize(); #vqo -y7@  
if(nFileLength == -1) ([V V%ovZ  
{ lM[XS4/TRa  
System.err.println("File Length is not known!"); =FT98H2*|  
} n7YEG-J  
else if(nFileLength == -2) VCcr3Dx()F  
{ ?[MsQQd~  
System.err.println("File is not access!"); tD Cw-  
} KB!|B.ChN(  
else ;eZ#bjw-d  
{ e~T@~(fft  
for(int i=0;i<nStartPos.length;i++) ;u(Du-Os!  
{ Mf#83 <&K  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); UYtuED  
} aRJ>6Q}  
for(int i=0;i<nEndPos.length-1;i++) 02k4 N%  
{ xlR2|4|8  
nEndPos = nStartPos[i+1]; 35x 0T/8  
} 2.X"f  
nEndPos[nEndPos.length-1] = nFileLength; UP{j5gR:_  
} Y}DonF  
} @MK"X}3  
%,*G[#*&  
rBN)a"  
//启动子线程 G^1b>K  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vkRi5!bR  
for(int i=0;i<nStartPos.length;i++) :p4"IeKs  
{ L~^*u_U]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M-uMZQ e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lRP1&FH0  
nStartPos,nEndPos,i); iY bX  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cubk]~VD  
fileSplitterFetch.start(); n!E2_  
} *X38{r j  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2spg?]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =4 X]gW  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ij'NC C  
nEndPos = " + nFileLength); 47T}0q,  
// fileSplitterFetch[nPos.length-1].start(); do ^RF<G  
:` $@}GI  
m2Uc>S  
//等待子线程结束 ~/tKMS6T  
//int count = 0; }p9F#gr  
//是否结束while循环 M'1!<a-Mp  
boolean breakWhile = false; j,2l8?  
da$BUAqU  
^SfS~G Q  
while(!bStop) e|r0zw S  
{ ARfRsPxr  
write_nPos(); k 2%S`/:  
Utility.sleep(500); -NBiW6b~  
breakWhile = true; \BI/G  
|k{-l!HI  
?Jtg3AY  
for(int i=0;i<nStartPos.length;i++) oT|m1aGE  
{ w h$jr{  
if(!fileSplitterFetch.bDownOver) gK3Mms]}m  
{ - n6jG}01b  
breakWhile = false; RX2{g^V7  
break; s-V SH  
} fH8!YQG8$  
} &VWlt2-R0h  
if(breakWhile) Ld|V^9h1;  
break; ~L+]n0*  
g9my=gY  
4rU! 4l  
//count++; ^`qPs/b  
//if(count>4) em]xtya  
// siteStop(); &4$oudn  
} v&MU=Tcqi  
r5/R5Ga^  
u>Ki$xP1  
System.err.println("文件下载结束!"); ZZ)G5ji  
} swpnuuC-  
catch(Exception e){e.printStackTrace ();} "L2m-e6  
} ;' e@t8i6  
} IlP:  
e"+dTq8W  
//获得文件长度 cQFR]i  
public long getFileSize() twk&-:'  
{ f3 ]  
int nFileLength = -1; rvwy~hO"  
try{ 3,.% s  
URL url = new URL(siteInfoBean.getSSiteURL()); -0,4eg j3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +EASAq  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8kW/DcLE  
%TK&)Q% h5  
4^!4eyQ^  
int responseCode=httpConnection.getResponseCode(); w&lZ42(mF  
if(responseCode>=400) s=EiH  
{ ;>2#@QP  
processErrorCode(responseCode); vg8O] YF  
return -2; //-2 represent access is error ?G/hJ?3  
} +CTmcbyOi  
Ds5N Ap:x  
^@}#me@  
String sHeader; 9[|4[3K  
(buw^ ,NwZ  
@%@zH%b  
for(int i=1;;i++) FUaNiAr[  
{ ,{j4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +*t|yKO>[  
//Utility.log(in.readLine()); .T3=Eq&"W  
sHeader=httpConnection.getHeaderFieldKey(i); Z%v6xP.  
if(sHeader!=null) jFj~]]j  
{ D&[Z;,CHMA  
if(sHeader.equals("Content-Length")) [{PqV):p  
{ U7%28#@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4=p@2g2"H  
break; }#b %"I0  
} Y5jYmP<  
} If}lJ6jZ  
else ;1LG&h,K  
break; U4wpjHg  
} i;lE5  
} _9h.Gt  
catch(IOException e){e.printStackTrace ();} [b5(XIGUN}  
catch(Exception e){e.printStackTrace ();} t]TyXAr~  
X N;/nU  
pVOI5>f\  
Utility.log(nFileLength); E8tD)=1  
y-cw~kNPP3  
[(c L/_  
return nFileLength; ,z66bnjO  
} (G5xkygR9  
m,NMTyJoz  
M j~${vj  
//保存下载信息(文件指针位置) V<$*Y>;  
private void write_nPos() [$2qna2VP  
{ t&"5dM\  
try{ 2xmT#m  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <PD|_nZT  
output.writeInt(nStartPos.length); &N{zkMf  
for(int i=0;i<nStartPos.length;i++) ?0npEz|  
{ )Z:m)k>r;  
// output.writeLong(nPos); ~.Q4c*_b  
output.writeLong(fileSplitterFetch.nStartPos); $j !8?  
output.writeLong(fileSplitterFetch.nEndPos); !3KPwI,  
} z^~U]S3  
output.close(); .S|-4}G(6  
} 3LrsWAz'  
catch(IOException e){e.printStackTrace ();} J<_1z':W)  
catch(Exception e){e.printStackTrace ();} XZ@ >]P  
} &PWf:y{R`  
x<Se>+  
{Tx 3$eU  
//读取保存的下载信息(文件指针位置) H^v{Vo  
private void read_nPos() n^6TP'r  
{ \DyKtrnm%  
try{ gDhl-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ype"7p\  
int nCount = input.readInt(); Y:%"K  
nStartPos = new long[nCount]; i;HH ! TaN  
nEndPos = new long[nCount]; V~c(]K)-  
for(int i=0;i<nStartPos.length;i++) kGj]i@(PA4  
{ o*)@oU  
nStartPos = input.readLong(); drX4$Kdf]  
nEndPos = input.readLong(); STp!8mL  
} 5V rcR=?O  
input.close(); Q=XA"R  
} t>@yv#  
catch(IOException e){e.printStackTrace ();} D'?]yyrf  
catch(Exception e){e.printStackTrace ();} \I xzdFF#  
} 0nT%Slbih  
ct.Bg)E  
b.(XS?4o  
private void processErrorCode(int nErrorCode) T]X{ @_  
{ G,/Gq+WX  
System.err.println("Error Code : " + nErrorCode); q"p#H8  
} !pV<n  
1G_xP^H!  
a}GAB@YI  
//停止文件下载 R]VTV7D  
public void siteStop() |3|wdzV  
{ *e,CDV  
bStop = true; YrKFa%k  
for(int i=0;i<nStartPos.length;i++) 5EfY9}dl  
fileSplitterFetch.splitterStop(); mN7&%Z  
9 G((wiE  
z.A4x#>-  
} k2wBy'M .'  
} Z#@6#S`  
//负责部分文件的抓取 5#BF,-Jv  
**FileSplitterFetch.java >VypE8H]x  
*/ 9OhR4 1B  
package NetFox; r"1A`89  
c_[ JjG^?P  
F94V5_[  
import java.io.*; L<"k 7)k  
import java.net.*; YN`UTi\s  
x:vrK#8D>  
4&H+hN{3  
public class FileSplitterFetch extends Thread {  TVj1C  
gBfX}EK7F  
#VQ36pCd  
String sURL; //File URL ! 7Nn ]Lx  
long nStartPos; //File Snippet Start Position 3lyQn "  
long nEndPos; //File Snippet End Position _i.({s&_9  
int nThreadID; //Thread's ID I@+lFG   
boolean bDownOver = false; //Downing is over ,$o-C&nC  
boolean bStop = false; //Stop identical dY 6B%V  
FileAccessI fileAccessI = null; //File Access interface (J/>Gy)d  
d[yrNB6|  
r \9:<i8  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i~(#S8U4d  
{ cyDiA(ot&  
this.sURL = sURL; ~S! L!qY  
this.nStartPos = nStart; -aA<.+  
this.nEndPos = nEnd; # e$\~cPd  
nThreadID = id; Y]?Kqc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]C+eJ0"A  
} 2}ag_  
Lq3(Z%  
THb A(SM  
public void run() dzpj9[  
{ ~igRg~k:/  
while(nStartPos < nEndPos && !bStop) |F3vRt@  
{ EmYO5Whi  
_dz +2au  
2c!h2$w  
try{ f*UBigk  
URL url = new URL(sURL); >_n:_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4b]IazL)  
httpConnection.setRequestProperty("User-Agent","NetFox"); J,MT^B  
String sProperty = "bytes="+nStartPos+"-"; gjO *h3`  
httpConnection.setRequestProperty("RANGE",sProperty); wYC9 ~ms-  
Utility.log(sProperty); r .{rNR  
}FuVY><l  
v4X_v!CQ  
InputStream input = httpConnection.getInputStream(); _QD/!~O  
//logResponseHead(httpConnection); p.qrf7N$  
9 J$Y,Z  
Qu!OV]Cc  
byte[] b = new byte[1024]; ;>cLbjD  
int nRead; gCjH%=s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R>^5$[  
{ 1{= E ?  
nStartPos += fileAccessI.write(b,0,nRead); +k# mvPq  
//if(nThreadID == 1) i%#th'C!P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5R$=^gE  
} :Fw *r|  
?S+/QyjcfJ  
p{+tFQy  
Utility.log("Thread " + nThreadID + " is over!"); i.B$?cr~  
bDownOver = true; {\ A_%  
//nPos = fileAccessI.write (b,0,nRead); ^[k6]1h  
} K'>P!R:El  
catch(Exception e){e.printStackTrace ();} l!xgtP K  
} IEKMa   
} [YL sEo=  
W66}\&5  
^!zJf7(+<>  
//打印回应的头信息 /DgT1^&0  
public void logResponseHead(HttpURLConnection con) <FMuWHY  
{ J@=!w[v+  
for(int i=1;;i++) $`cy'ZaF  
{ s|Imz<IE  
String header=con.getHeaderFieldKey(i); {X{01j};8  
if(header!=null) %Z-TbOX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #c8"  
Utility.log(header+" : "+con.getHeaderField(header)); C?_t8G./_  
else &utS\-;G  
break; Pl`Bd0  
} W$x K^}  
} n^g-`  
t!+%g) @  
7$E2/@f  
public void splitterStop() %3#b6m~  
{ CNpCe-%&  
bStop = true; A5(kOtgiT  
} SLbavP#G  
 |V*e2w  
)wyu+_:  
} N^@%qUvT]  
ur,V>J<5A  
gK]T}  
/* 'Q^G6'(SaK  
**FileAccess.java \oD=X}UQw(  
*//文件访问(定位,写) r zc 3k~@  
package NetFox; % B7?l  
import java.io.*; AZBY, :>D  
]G$!/vXP  
2=/-d$  
public class FileAccessI implements Serializable{ -NI@xJO4(;  
&**.naSo  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 RQ_#rYmT  
RandomAccessFile oSavedFile; ~a0d .dU  
long nPos; r;5 AY  
]VO,} `  
0^|$cvYiL  
public FileAccessI() throws IOException j:\_*f  
{ -h.3M0  
this("",0); 7D9h;gsP  
} A=l?IC@O  
AH ?MJKY@Z  
`zV-1)=  
public FileAccessI(String sName,long nPos) throws IOException MXu+I,y*  
{ E(L^hZMc  
oSavedFile = new RandomAccessFile(sName,"rw"); $$)<(MP3  
this.nPos = nPos; .WPuQZ!  
oSavedFile.seek(nPos); )Uoe ~\  
} /Wta$!X{-  
P89Dg/P  
:W1tIB  
public synchronized int write(byte[] b,int nStart,int nLen) hyr5D9d  
{ _^,[wD  
int n = -1; RvZryA*vu  
try{ 'ra_Zg[j  
oSavedFile.write(b,nStart,nLen); @b(gjOE  
n = nLen; YC+ZVp"v  
} //@sktHsw(  
catch(IOException e) (kD?},Z  
{  _j?=&tc  
e.printStackTrace (); tL 9e~>,`  
} 55)ep  
xDAA`G  
{U2| ):  
return n; ]'z ^Kt5S  
} :EmMia-)J  
Ky{I&}+R|  
:O_<K&  
} Yru1@/;  
#0$eTdx#  
PSt|!GST  
/* TBLk+AR  
**SiteInfoBean.java 8Gzs  
*/ =z7 Ay  
package NetFox; n ;$}pg ~  
pRyS8'  
::h02,y;1%  
public class SiteInfoBean { Ts?>"@  
KfI$'F #"/  
;z=C^'  
private String sSiteURL; //Site's URL I n%yMH8  
private String sFilePath; //Saved File's Path 1Y"y!\t7G  
private String sFileName; //Saved File's Name GCmVmOdKr  
private int nSplitter; //Count of Splited Downloading File *1 eTf  
'3kL=(  
aABE= 9Y  
public SiteInfoBean() we@En .>f  
{//nSplitter的缺省值为5 (Su2 \x  
//default value of nSplitter is 5 0yEyt7 ~@  
this("","","",5); )SZ,J-H08w  
} 5=;I|l,  
kv FOk  
!D]6Cq  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) '}[L sU  
{ c^/?VmCQ}  
sSiteURL= sURL; nV6g]#~ @  
sFilePath = sPath; g960;waz3  
sFileName = sName; ri_6 wbPp  
this.nSplitter = nSpiltter; `oI/;&  
x'PjP1  
\|4MU"ri  
} J}`$WL:  
)^a#Xn3z  
[/`Hz]R  
public String getSSiteURL() _TeRsA  
{ iPi'5g(a   
return sSiteURL; 2ZFK jj  
} Gt *<?  
,'0oj$~S:  
tfU3 6PR  
public void setSSiteURL(String value) /3HWP`<x  
{ [T&y5"@  
sSiteURL = value; UyfIAC$S  
} ~\(>m=|C:H  
+_K;Pj]x  
dg@/HLZ  
public String getSFilePath() :a<TV9?H0  
{ %>}7 $Y%  
return sFilePath; Z["nY&.sI  
} ~5?n&pF  
U@ QU8  
4BL,/(W] x  
public void setSFilePath(String value) wOl-iN=  
{ SYhspB  
sFilePath = value; %3B>1h9N  
} .0/Z'.c 8  
E;e2{@SX2K  
iPL'JVPZ  
public String getSFileName() YQd&rkr  
{ bI0+J)  
return sFileName; ~Am %%$  
} 17i@GnbNb  
.j@n6RyN  
@ dU3d\!}  
public void setSFileName(String value) 4'e8VI0  
{ 'F<e)D?  
sFileName = value; ^bw~$*"j#  
} vX)Y%I  
ap_+C~%+  
?B4QTx9B  
public int getNSplitter() /9^0YC;Y*  
{ N.cRZm%  
return nSplitter; |?b"my$g$  
} s+t eYL#Zi  
F4l6PGxF&\  
QU;C*}0Zl  
public void setNSplitter(int nCount) K&oO+G^f  
{ K%@SS8!oy  
nSplitter = nCount; DcM+K@1E4^  
} `SbX`a0p2  
} T$B4DQ  
~x\ Q\Cxp  
@WE$%dr  
/* mM%BO(X{=  
**Utility.java mT$tAwzTC{  
*/ "N"k8,LH  
package NetFox; I!#^F 1p1  
6E&&0'm  
Wm/k(R`O<  
public class Utility { akoKx)(<  
a{6|[a R  
AFA*_9Ut  
public Utility() aM1JG$+7G  
{ YZJP7nN  
AV`7> @  
eW<hC (  
} No+zw%l0E  
$h f\ #'J  
//线程睡眠 Nd)o1 {I  
public static void sleep(int nSecond) ?*dx=UI  
{ ps J 1J  
try{ j> M%?Tw  
Thread.sleep(nSecond); FkkB#Jk4  
} 0`=?ig_  
catch(Exception e) $~\qoW<  
{ c9k,Dc  
e.printStackTrace (); B75SLK:h=  
} c9={~  
} Q&;qFv5-l  
Q:=/d$*xd  
//日志 k9?+9bExXA  
public static void log(String sMsg) 40ZB;j$l  
{ zYJxoC{  
System.err.println(sMsg); '^AXUb  
} (J#3+I  
4 ETVyK|  
nwVtfsb  
public static void log(int sMsg) ] lTfi0}g_  
{ 2%H( a)  
System.err.println(sMsg); #$QY[rf=6  
} ttRH[[E(  
} zW.sXV,  
9|DC<Zn&B#  
IA!Kp g W  
/* 6Z=H>w  
**TestMethod.java ybkN^OEJ  
*/ s|oU$?eA  
package NetFox; Wn5]2D\vkT  
["9$HL  
('oUcDOFTS  
public class TestMethod { JASn\z  
Z2 4 m  
@x4Dt&:"  
public TestMethod() E$ rSrT(  
{ ///xx/weblogic60b2_win.exe ~VKXL,.  
try{ $T0[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); sP7(1)\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); R~([  
SiteFileFetch fileFetch = new SiteFileFetch(bean); C]cw@:o%  
fileFetch.start(); @TDcj~oR ?  
} tp&iOP6O  
catch(Exception e){e.printStackTrace ();} 4dAhJjhgD  
}+1oD{  
x.Y,]wis  
} @YELqUb*  
p IToy;]  
p,/^x~m3a  
public static void main(String[] args) bHM .&4G  
{ yuB BO:\.  
new TestMethod(); C~*m&,@TT^  
} &$f?XdZ7  
} 4YC`dpO'  
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