http断点续传简单实现（java)

/* NO*,}aeG  
**SiteFileFetch.java ?xaUWD  
*/ 4u5j 7`O  
package NetFox; C1-U2@  
import java.io.*; a?-Jj\q  
import java.net.*; nFni1cCD  
&eV5#Ph  
["nWIs[h  
public class SiteFileFetch extends Thread { DGJ:#UE  
?c8~VQaQ  
_f!ko<52  
SiteInfoBean siteInfoBean = null; //文件信息Bean I[%IW4jJ  
long[] nStartPos; //开始位置 EP38Ho=[  
long[] nEndPos; //结束位置 .w4|$.H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 z_'^=9m  
long nFileLength; //文件长度 Qy:yz  
boolean bFirst = true; //是否第一次取文件 _h1bVd-  
boolean bStop = false; //停止标志 Sj ovL
@X  
File tmpFile; //文件下载的临时信息 @JSWqi>  
DataOutputStream output; //输出到文件的输出流 0eO!,/  
$PM
r)U  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） n~0wq(8M  
public SiteFileFetch(SiteInfoBean bean) throws IOException />xEpR3_A  
{ a@? $#>  
siteInfoBean = bean; ^6Aa^|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8g=O0Gb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S*Ea" vBA  
if(tmpFile.exists ()) i7dDklj4  
{ ,.Ofv):=  
bFirst = false; E]q>ggeNH  
read_nPos(); xiW}P% bf  
} wQ(DX!   
else Cx;it/8+  
{ lZwjrU| _  
nStartPos = new long[bean.getNSplitter()]; }P2*MrkcHB  
nEndPos = new long[bean.getNSplitter()]; 0-p^oA  
} Ow-ejo  
S[y'{;  
m !:F/?B  
Ps0Cc_  
} ` ,T.  
b#7nt ?`7p  
(B` NnL$  
public void run() 1<9d[N*  
{ ky !ZJR  
//获得文件长度 5JOfJ$(n  
//分割文件 :/6:&7s  
//实例FileSplitterFetch p cD}SY
 
//启动FileSplitterFetch线程 k8E2?kbF  
//等待子线程返回 uhq6dhhR  
try{ 9ZOQNN<ex  
if(bFirst) _ (b4|hJ'  
{ kYS#P(1  
nFileLength = getFileSize(); /;_$:`|/  
if(nFileLength == -1) gB#!g@  
{ ${Lrj}93  
System.err.println("File Length is not known!"); ~/4j&IG  
} ~JZLWTEe  
else if(nFileLength == -2) eZ
) |m  
{ ~H''RzN  
System.err.println("File is not access!"); y2%[/L:u~  
} em'3 8L|(  
else .dzw5R&  
{ 5@.8O
VPz  
for(int i=0;i<nStartPos.length;i++) KUW )F  
{ 6+sz4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |vi=h2*  
} ?z`yNx6  
for(int i=0;i<nEndPos.length-1;i++) v*excl~  
{ KXTk.\c  
nEndPos = nStartPos[i+1]; L^^f.w#m  
} G} [$M"}  
nEndPos[nEndPos.length-1] = nFileLength; G]l/L\{  
} |x.[*'X@  
} d>M0:  
XPYf1
H  
lN.&46 e  
//启动子线程 F
\+9u$=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6jr}l  
for(int i=0;i<nStartPos.length;i++) O0^Y1l  
{ 1|*%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t":^:i'M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [9EL[}  
nStartPos,nEndPos,i); #~*v*F~3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =]Y'xzJuu  
fileSplitterFetch.start(); D{]w+  
} "`K73M,c?9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;|rFP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s/?(G L+Ae  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", x=JZ"|TE  
nEndPos = " + nFileLength); aS3-A4  
// fileSplitterFetch[nPos.length-1].start(); <c`,fd8  
}2y"F@{T  
a6T!)g  
//等待子线程结束 8QFRX'i  
//int count = 0; Rv*x'w ==  
//是否结束while循环 #!z'R20PH  
boolean breakWhile = false; !H^R_GC  
sN
[q.M?  
PClwGO8'&  
while(!bStop) f$nZogaQ  
{ Z_<Wr7D  
write_nPos(); n-9X<t|*?a  
Utility.sleep(500); DKQQZ`PF  
breakWhile = true; ,J*#Ixe}  
a;7gy419<p  
mX SLH'  
for(int i=0;i<nStartPos.length;i++) bxz6 >>  
{ 7Il /+l(  
if(!fileSplitterFetch.bDownOver) .@(MNq{"6  
{ hEFn>  
breakWhile = false; A|L-;P NP  
break; My9fbT  
} p'SY 2xq-,  
} YWhS<}^  
if(breakWhile) 1p>&j%dk  
break; b#e|#!Je  
@(st![i+  
+]
Bx4r?p  
//count++; %gEfG#S  
//if(count>4) Rm.9`<Y  
// siteStop(); ilj9&.isB  
} ctC!b{S"@  
kZ_5R#xK  
cRPy5['E  
System.err.println("文件下载结束！"); JENq?$S  
} `Oi6o[a  
catch(Exception e){e.printStackTrace ();} `H;O! ty&d  
} ]kkH|b$[T  
/Bnh%6#ab  
& V/t0  
//获得文件长度 8-vNXvl  
public long getFileSize() 5|[\Se#  
{ BYDOTy/%nJ  
int nFileLength = -1; Se5jxV  
try{ LTY(6we-  
URL url = new URL(siteInfoBean.getSSiteURL()); "6'
# L,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U}`HN*Q.q  
httpConnection.setRequestProperty("User-Agent","NetFox"); iGeuO[^  
F[|aDj@q e  
\h/aD1&g  
int responseCode=httpConnection.getResponseCode(); l< |)LDq~  
if(responseCode>=400) W^nG\"T^  
{ 0Z[8d0  
processErrorCode(responseCode); } SA/,4/9  
return -2; //-2 represent access is error v?1xYG@1  
} m>?{flO  
EEp,Z`  
~_L_un.R  
String sHeader; tTrue?  
78+PG(Q_M  
:] +D+[c)  
for(int i=1;;i++) k!,&L$sG  
{ blB00   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n47v5.Wn  
//Utility.log(in.readLine()); b{d@:"  
sHeader=httpConnection.getHeaderFieldKey(i); t?kb
N\,  
if(sHeader!=null) ;,]Wtmu)7  
{ ~); 7D'[  
if(sHeader.equals("Content-Length")) ;i&'va$  
{ Zz04Pz1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); hI1}^;  
break; |4FvPR[  
} hbdM}"&]  
} 0~XZ  
else j1,ir  
break; {7X80KI  
} bc|DC,n?  
} HTCn=MZm ?  
catch(IOException e){e.printStackTrace ();} >'lte&  
catch(Exception e){e.printStackTrace ();} -5yEd>Z  
3+jqf@fO  
9a9{OJa6M  
Utility.log(nFileLength); *] cm{N  
rfMzHY}%  
/e}NZo{)g  
return nFileLength; p[%FH?  
} _gF )aE  
Dx27s  
`=3:*.T*  
//保存下载信息（文件指针位置） 4jl
-?  
private void write_nPos() 7fJWb)z!k  
{ !_gHIJiq}  
try{ !N1DJd  
output = new DataOutputStream(new FileOutputStream(tmpFile)); p9)'nU'\t  
output.writeInt(nStartPos.length); +K%4jIm  
for(int i=0;i<nStartPos.length;i++) e[7n`ka '  
{ %<8lLRl  
// output.writeLong(nPos); 8FT
hu[  
output.writeLong(fileSplitterFetch.nStartPos); v5GV"qY  
output.writeLong(fileSplitterFetch.nEndPos); q>*+.~  
} 8?O6IDeW  
output.close(); 5}4r'P$m:  
} x;Jy-hMNl  
catch(IOException e){e.printStackTrace ();} xV4 #_1(  
catch(Exception e){e.printStackTrace ();} _ZfJfd~  
} rBZ0(XSZQ  
i7w>Nvj]  
sc^TElic  
//读取保存的下载信息（文件指针位置） 7x^P
74  
private void read_nPos() 58Fan*fO  
{ z\8Kz ]n~  
try{ F\Gi;6a  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #yk m  
int nCount = input.readInt(); ]QS?fs Z  
nStartPos = new long[nCount]; +idj,J|  
nEndPos = new long[nCount]; *s9 +  
for(int i=0;i<nStartPos.length;i++) 'lym^^MjL+  
{ yb#NB)+E@  
nStartPos = input.readLong(); -qBrJ1*  
nEndPos = input.readLong(); Vx^+Z,y&QP  
} qqSf17sW  
input.close(); ~%QVjzMC  
} afcI5w;>}  
catch(IOException e){e.printStackTrace ();} i
y{*w&p  
catch(Exception e){e.printStackTrace ();} c?{&=,u2  
} z5v)~+"1  
7N/v  
m]$!wp  
private void processErrorCode(int nErrorCode) T^ ^o  
{ S&% GB  
System.err.println("Error Code : " + nErrorCode); %klC& _g~_  
} nTweQ  
#s)Wzv%OX  
LuB-9[^<  
//停止文件下载 /,z4tf  
public void siteStop() R*D0A@  
{ 61q:nWs  
bStop = true; gjJ?*N[  
for(int i=0;i<nStartPos.length;i++) \4`~J@5Y  
fileSplitterFetch.splitterStop(); u+GtH;<;  
8=H!&+aGh  
Yqy7__vm  
} JZP>`c21y]  
} +.T&U7x
V  
//负责部分文件的抓取 hGx)X64Mw  
**FileSplitterFetch.java ((TiBCF4  
*/ |>(;gr/5(  
package NetFox; jX79Nm|  
PYYOC"$  
S$Tc\/{  
import java.io.*; w^?uBeqR  
import java.net.*; T<"Hh.h  
N246RV1W  
-gl7mO*  
public class FileSplitterFetch extends Thread { vl8Ums} +  

SNB>  
J)iy6{0"  
String sURL; //File URL WhsTKy&E  
long nStartPos; //File Snippet Start Position jemg#GB8  
long nEndPos; //File Snippet End Position q"@Y2lhD!  
int nThreadID; //Thread's ID K%ltB&  
boolean bDownOver = false; //Downing is over `w1|(Sk$h  
boolean bStop = false; //Stop identical vd>X4e^j  
FileAccessI fileAccessI = null; //File Access interface ]?p&sI4  
_6"!y ]Q  
0!YB.=\{_q  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )pV5l|`  
{ j()<.h;'  
this.sURL = sURL; +(*S@V$c  
this.nStartPos = nStart; ;#G)([  
this.nEndPos = nEnd; -(4)lw>U  
nThreadID = id; 445}Yw5;9  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Cvr?%+)$M  
} q$Z.5EN
 
,lLkAd?q  
4i>sOP3 B  
public void run() gwtR<2,p  
{ 3zU!5
tg  
while(nStartPos < nEndPos && !bStop) 6H,n?[zTt  
{ L,L>cmpM  
R87-L*9B^0  
xwr<ib:  
try{ !j,LS$tPu  
URL url = new URL(sURL); #;?j]npg]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w~A{]s{4  
httpConnection.setRequestProperty("User-Agent","NetFox"); dHV3d'.P  
String sProperty = "bytes="+nStartPos+"-"; &R:$h*Wt|  
httpConnection.setRequestProperty("RANGE",sProperty); y<bA Y_-[  
Utility.log(sProperty); 2yk32|  
6vySOVMj  
|[/[*hDZ9  
InputStream input = httpConnection.getInputStream(); 8{aS$V"  
//logResponseHead(httpConnection); I^*&u,  
'`$z!rA  
c=iv\hn  
byte[] b = new byte[1024]; D3s]
49j)  
int nRead; hce *G@b  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \M-}(>Pfk  
{ x}t,v
.:  
nStartPos += fileAccessI.write(b,0,nRead); ^W|B Xxo  
//if(nThreadID == 1) 1@*qz\ YY  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
@Omgk=
6  
} ;v0M ::  
aV?dy4o$  
^sR]w]cz.  
Utility.log("Thread " + nThreadID + " is over!"); Nf(Np1?;c  
bDownOver = true; J0@<6~V6o  
//nPos = fileAccessI.write (b,0,nRead); d?G~k[C!a  
} #?/&H;n_8S  
catch(Exception e){e.printStackTrace ();} Y;ytm #=  
} fG2
hCP+  
} B2\R#&X.  
a[;TUc^I1F  
bkfwsYZx  
//打印回应的头信息 =~M%zdIXv  
public void logResponseHead(HttpURLConnection con) <WN?  
{ bjvpYZC\5  
for(int i=1;;i++) ^sz4-+>  
{ rxZ%vzVQ>  
String header=con.getHeaderFieldKey(i); LWQ.!;HYp  
if(header!=null) [jb3lO$Xa  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [\(}dnj:  
Utility.log(header+" : "+con.getHeaderField(header)); ZPHiR4fQli  
else ^.5`jdk  
break; 8zv=
@`4@G  
} }}Gz3>?24=  
} }TjiYA.  
GORu*[U8  
o RT<h  
public void splitterStop() VhdMKq~`  
{ "J|_1!9  
bStop = true; fx&b*OC  
} $^|I?5xD  
]B'Ac%Rx  
88\0opL-  
} jb~2f2vUa  
TX7B(JZD  
HPT{83  
/* \*{tAF  
**FileAccess.java IR; DdF  
*//文件访问(定位，写) Jj=0{(X  
package NetFox; [C)JI;\  
import java.io.*; ,MkldCV  
6q^Tq {I  
TEC'
}%   
public class FileAccessI implements Serializable{ jx_n$D  
M>H4bU(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2n}nRv/'  
RandomAccessFile oSavedFile; W\xM$#
)m  
long nPos; 6")co9  
@* a'B=7  
e!cZW.B=`f  
public FileAccessI() throws IOException 72oiO[>N'  
{ OnGtIY  
this("",0); Hd)z[6u8eT  
} c5~d^  
TNYd_:j  
hZ_
0lX}  
public FileAccessI(String sName,long nPos) throws IOException _2*Ryz  
{ moO=TGG;F  
oSavedFile = new RandomAccessFile(sName,"rw"); @Y2"=QVt  
this.nPos = nPos; JN;92|x  
oSavedFile.seek(nPos); V. sIiE  
} ^<L;"jl%  
9y/gW
E  
;DWtCtD  
public synchronized int write(byte[] b,int nStart,int nLen) Yv0;UKd  
{ 9$0-UUCk  
int n = -1; s':fv[%  
try{ joaf0  
oSavedFile.write(b,nStart,nLen); yP:/F|E$  
n = nLen; &mebpEHUG7  
} Op] L#<&T  
catch(IOException e) wm@/>X  
{ 1
S!<D)n  
e.printStackTrace (); hR;J#w  
} @)0-oa,u+  
q7id?F}3&  
I{Pny/d`  
return n; /rRQ*m_  
} b}P5*}$:9"  
-OLXRc=  
5fGUJ[F=  
} \VW&z:/*pZ  
.:eNL]2%:  
]V9z)uz  
/* .BLF7> M1  
**SiteInfoBean.java fneg[K  
*/ :v/6k  
package NetFox; \<ohe w  
(`0dO8  
@d5G\1(%  
public class SiteInfoBean { z?~W]PWiZ  
Iq&S6l <0  

lLuAZoH  
private String sSiteURL; //Site's URL =6#tJgg8  
private String sFilePath; //Saved File's Path 2Z]<MiAxD  
private String sFileName; //Saved File's Name !oXA^7Th6]  
private int nSplitter; //Count of Splited Downloading File #UN(R  
Rg*zUfu5%o  
?H9F"B$a  
public SiteInfoBean() G-FTyIP>'  
{//nSplitter的缺省值为5 xJ"CAg|
B  
//default value of nSplitter is 5 {.7ve<K  
this("","","",5); Ln;jB&t  
} g*9jPwdG  
$"Oy }  
;]<{<czc  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B!jINOg  
{
[ e4)"A"  
sSiteURL= sURL; !x9j~D'C`  
sFilePath = sPath; wEK@B&DV  
sFileName = sName; ^'8T9N@U  
this.nSplitter = nSpiltter; @Yua%n6]#D  
HLMEB0zh^  
C7=Q!UK`\  
} M4a-+T"  
,j~R ^j  
b@J&jE~d  
public String getSSiteURL() tMaJ; 4  
{ 02]9OnWw  
return sSiteURL; )=\W sQ  
} UXB[3SP  
@Kri)U i
 
mfu>j,7l  
public void setSSiteURL(String value) g;(r@>U.r  
{ w;$@</  
sSiteURL = value; S3"
js4a  
} M%7H-^{  
JL1%XQ i  

z"BV+  
public String getSFilePath() rVkoj;[  
{ |Iy55~hK`  
return sFilePath; D5X;hd  
} 5*1wQlL  
1r}fnT<  
=+gp~RR,  
public void setSFilePath(String value) NF=FbvNe  
{ 6Rn_@_Nn)f  
sFilePath = value; $;*YdZ`q  
} l79jd%/m  
q>&F%;q1]  
'3uj6Wq2  
public String getSFileName() ~B%EvG7
:n  
{ N}\Da:_  
return sFileName; v>Il#  
} |dNtM^  
ZNPzQ:I@  
/2oTqEqaV  
public void setSFileName(String value) vCwDE~  
{ ?,r bD1  
sFileName = value; "fLGXbNQ  
} *qg9~/  
/qF7^9LtaY  
O?@1</r^  
public int getNSplitter() {xt<`_R  
{ yy?|q
0  
return nSplitter; G?QFF6)}!  
} ~c!zTe  
EU,4qO  
6<H[1PI`,G  
public void setNSplitter(int nCount) U-TwrX  
{ 32:,g4!~6  
nSplitter = nCount; W0$G7s  
} :EyH'v  
} pooi8" G  
:^kP?  
!mL,Ue3/  
/* ac.O#6&  
**Utility.java \E.t=XBn  
*/ e%G-+6  
package NetFox; ~0?p @8  
{mL/)\  
ORa!84L  
public class Utility { &F\J%#{  
9G_=)8sOV  
`.%;|"xR  
public Utility() d8M"vd  
{ ,?B.+4CW\E  
?OKm~ Ek  
*6*#"#D  
} cFUYT$8>  
d^ !3bv*h  
//线程睡眠 H'I|tPs  
public static void sleep(int nSecond) CV4V_G  
{ U^Z[6u  
try{ 3HbHl?-UNU  
Thread.sleep(nSecond); Xkl^!,  
} 4PiNQ'*  
catch(Exception e) XoSjYG(>,  
{ p"H8;fPA0  
e.printStackTrace (); 0P/A  
} O( h
e  
} ~B(]0:  
YO!,m<b^u  
//日志 = k3O4gE7  
public static void log(String sMsg) q~trn'X>  
{ |!%A1 wp#  
System.err.println(sMsg);
*U54x /w|  
} QVn0!R{  
[
&nwB!kt  
U]R?O5K  
public static void log(int sMsg) 8tA.d.8  
{ wt2S[:!p  
System.err.println(sMsg); 3N+P~v)T'  
} /F;*[JZIb  
} =La}^  
9b]U&A$  
eiEZtu  
/* F:pXdU-xf  
**TestMethod.java v/+dx/  
*/ 0y;&L63>T  
package NetFox; #j-,#P@  
g#[9O'H  
`8FC&%X_  
public class TestMethod { ]Jnf.3  
YGWb!|Z$  
iZMsN*9[  
public TestMethod() #-'}r}1ZT  
{ ///xx/weblogic60b2_win.exe k|A!5A2  
try{ ]Vb#
(2<2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); NYP3uGH]
  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -&)^|Atm  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,;+\!'lS  
fileFetch.start(); 7Wb.(` a<  
} lR.a3.~  
catch(Exception e){e.printStackTrace ();} {+xUAmd  
u~s'<c+8_  
dt`L}Yi  
} =AD/5E,3  
%4 SREq  
v9inBBC q  
public static void main(String[] args) _D,8`na>K  
{ tB_V%qH  
new TestMethod(); hsqUiB tc6  
} W$'pUhq\H  
} /kw4":{]  
点击下载更多相关资料