http断点续传简单实现（java)

/* )Yy5u'}  
**SiteFileFetch.java (b//YyqN  
*/ $j\>T
@  
package NetFox; \WFcb\..  
import java.io.*; H Eq{TUTr  
import java.net.*; M.t,o\xl  
;Y;r%DJ  
X/2GTU7?  
public class SiteFileFetch extends Thread { V
fpT5W<  
*{#C;"  
dv\bkDF4A  
SiteInfoBean siteInfoBean = null; //文件信息Bean 4z(B`t~7  
long[] nStartPos; //开始位置 /7#e  
long[] nEndPos; //结束位置 /i>n1>~yn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 bpZA%{GS  
long nFileLength; //文件长度 ?s
$d("~  
boolean bFirst = true; //是否第一次取文件 \f^xlX3&`  
boolean bStop = false; //停止标志 WyatHC  
File tmpFile; //文件下载的临时信息 V9$T=[  
DataOutputStream output; //输出到文件的输出流 IxuK<Oe:O  
l%_K
$$C  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <{k{Coy  
public SiteFileFetch(SiteInfoBean bean) throws IOException O$6&4p*F.  
{ RR[zvH} E  
siteInfoBean = bean; W
/BPf{U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7d%x7!E  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); u@e.5_:S)  
if(tmpFile.exists ()) 1Mp-)-e  
{ uT,i&  
bFirst = false; \B~g5}=  
read_nPos(); lj}3TbM  
} i!}k5k*Z  
else <!RkkU& 6  
{ ~wuCa!!A  
nStartPos = new long[bean.getNSplitter()]; -(?/95 Y  
nEndPos = new long[bean.getNSplitter()]; +7w5m  
} o%
~fJx:]y  
<e BmCrJ  
hOk
9y=  
^yB]_*WJ  
} iT==aJ=~/&  
VI4mEq,V  
[ K/l;Zd  
public void run() &j:prc[W  
{ `&c[s%0  
//获得文件长度 S\N l|U[  
//分割文件 wT!?.Y)aj  
//实例FileSplitterFetch 0-uj0"r`  
//启动FileSplitterFetch线程 >4wigc  
//等待子线程返回 Wtu-g**KN  
try{ Ag0w8F  
if(bFirst) 6 DQOar>d  
{ ek5j;%~g1  
nFileLength = getFileSize(); A7YCSjB  
if(nFileLength == -1) ?&:N|cltD  
{ l,Q`;v5|  
System.err.println("File Length is not known!"); r>8`gAhx  
} _s#J\!F  
else if(nFileLength == -2) lW-G]V  
{ 9-j-nx @)  
System.err.println("File is not access!"); -T+YMAFU_  
} [4qvQ7Y !  
else h] )&mFiE"  
{ h;E.y   
for(int i=0;i<nStartPos.length;i++) &Pv$nMB$I  
{ `TF3Ho\MC  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); se3EI1
e  
} #bGYHN  
for(int i=0;i<nEndPos.length-1;i++) e 0$m<5  
{ !N\_D  
nEndPos = nStartPos[i+1]; DZESvIES  
}
d/TFx  
nEndPos[nEndPos.length-1] = nFileLength; wk'(g_DP  
} 7dB_q}<  
} :O,,fJ<x.O  
x=
K'Jj  
=dKk #*  
//启动子线程 bjj F{T  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +=L+35M  
for(int i=0;i<nStartPos.length;i++) o=5hG9dj  
{ H`3w=T+I  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1G(wESe  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), l)KN5V  
nStartPos,nEndPos,i); C]zgVbu  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1-4[w *u>  
fileSplitterFetch.start(); Uq%|v  
} #N=_-
  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?q'r9Ehe  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); t!ZFpMv]n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [h\_yU[P  
nEndPos = " + nFileLength); ybB<AkYc  
// fileSplitterFetch[nPos.length-1].start(); `lO/I+8  
Ujly\ix`  
OL&VisJ{75  
//等待子线程结束 ~1{~iB2G  
//int count = 0; Rn whkb&&  
//是否结束while循环 W?@+LQa??  
boolean breakWhile = false; ><@& &u.  
TF,a`?c`  
1]jUiX=T  
while(!bStop) x\(yjNZH  
{ z:W1(/W~  
write_nPos(); ;W#/;C _h  
Utility.sleep(500); {S5D~A*a+  
breakWhile = true; 3nkO+qQ  
4>[tjz.?k  
~;Xkt G:  
for(int i=0;i<nStartPos.length;i++) <b;Oap3  
{ |teDe6\m  
if(!fileSplitterFetch.bDownOver) \~q cYp  
{ gIXc-=Ut  
breakWhile = false; c)o[3o7  
break; oWc +i U(  
} 7dU7cc  
} gb0ZGnI  
if(breakWhile) V_7xXuM/  
break; x5Ee'G(  
&^YY>]1Py  
H{T)?J~  
//count++; VI`x fmVOQ  
//if(count>4) $bKa"T*  
// siteStop(); ^i^S1h"  
} uNY]%[AnJ  
a[8_O-  
Z [5HI;  
System.err.println("文件下载结束！"); 9aC>gye!  
} GOwd=]e  
catch(Exception e){e.printStackTrace ();}  D-4PEf  
} }H,A T  
+T^m  
D\V}Eo';6  
//获得文件长度 .+B)@?  
public long getFileSize() sinG $=  
{ {YbqB6zaM  
int nFileLength = -1;  "rjJ"u1  
try{ LbYI{|_Js  
URL url = new URL(siteInfoBean.getSSiteURL()); 7\/O"Ot  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dF.T6b  
httpConnection.setRequestProperty("User-Agent","NetFox"); MB |(,{S  
3P\I;xM  
&1':s|c  
int responseCode=httpConnection.getResponseCode(); $qrr]U  
if(responseCode>=400) DU7Ki6  
{ *<A;jP  
processErrorCode(responseCode); >I
a(g0  
return -2; //-2 represent access is error ev guw*u  
} F9+d7 Y$  
yED^/=\)}  
4 ?c1c  
String sHeader; O#U
"c5%  
CM#EA"9  
&4%J35~  
for(int i=1;;i++) Z{CL!  
{ [;2:lbPx  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,6bMfz  
//Utility.log(in.readLine()); ["IJh  
sHeader=httpConnection.getHeaderFieldKey(i); g|HrhUT;  
if(sHeader!=null) F@lpjW  
{ bOdv]nQ1  
if(sHeader.equals("Content-Length")) Rp|&1nS  
{ DnFl*T>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^k(eRs;K  
break; @[RY8~  
} #G=QL(f>/  
} )l}wjKfgO  
else "poTM[]tZ7  
break; r97[!y1gt  
} z\Y^x9  
} 7uxPkZbb  
catch(IOException e){e.printStackTrace ();} t g*[%Jf^  
catch(Exception e){e.printStackTrace ();} yjR O9  
PI \,`^)y  
,O)\,tg  
Utility.log(nFileLength); JJ0 CM:xe  
J-<B*ot+lX  
'm5(MC,  
return nFileLength; <&%1pZ/6.  
} ydqmuZ%2h#  
WbWW=(N'd  
k1U8w
doT  
//保存下载信息（文件指针位置） ^!F5Cz 48  
private void write_nPos() -+>r4P  
{ e@-Mlq)  
try{ Cj 2Xl  
output = new DataOutputStream(new FileOutputStream(tmpFile)); v<%kd[N  
output.writeInt(nStartPos.length); '8l yj&  
for(int i=0;i<nStartPos.length;i++) nQ642i%RQ  
{ 3@yTzaq6  
// output.writeLong(nPos); :6W^ S/pf  
output.writeLong(fileSplitterFetch.nStartPos); JEsLF{  
output.writeLong(fileSplitterFetch.nEndPos); `.>k)=F&  
} G'O/JM  
output.close(); `V&1]C8x  
} `S\zqF<  
catch(IOException e){e.printStackTrace ();} lMC{SfdH  
catch(Exception e){e.printStackTrace ();} ou'~{-_xd  
} ]cm6 |`pz  
FxCZRo&  
g@~!kh,TH  
//读取保存的下载信息（文件指针位置） \ ]   
private void read_nPos() V@D]bV@4  
{ 9Uha2o  
try{ .
xGo\aD  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *5'.!g('  
int nCount = input.readInt(); ^q ;Cx7T_p  
nStartPos = new long[nCount]; )kYOHS  
nEndPos = new long[nCount]; `} =yG_!A  
for(int i=0;i<nStartPos.length;i++) NbtGlSs8  
{ W9Nmx3ve  
nStartPos = input.readLong(); ncv7t|ZN  
nEndPos = input.readLong(); ;54(+5pqx  
} $Pxb1E  
input.close(); t9FDU  
} 
q-nER<  
catch(IOException e){e.printStackTrace ();} ['cz;2{:W  
catch(Exception e){e.printStackTrace ();} 5 L/x-i  
} /.R<,/gj  
x)SralWb  
)I`if(fG  
private void processErrorCode(int nErrorCode) K R,z^9  
{ c 6"Ib)  
System.err.println("Error Code : " + nErrorCode); }#1/fok  
} `&!k!FZY*  
3BdX  
kJ{+M]pW  
//停止文件下载 IXpc,l `  
public void siteStop() aS84n.?vq  
{ f>2MI4nMG  
bStop = true; 8)L*AdDAW!  
for(int i=0;i<nStartPos.length;i++) OGOND,/R?/  
fileSplitterFetch.splitterStop(); 0.TaXb
i  
W$0^(FH[  
c!#:E`  
} &@% $2O.3  
} h6~$/`&]b  
//负责部分文件的抓取 'Gl&Pa1g?  
**FileSplitterFetch.java 0[Ht_qxb  
*/ k(t}^50^j  
package NetFox; ,:LA.o
}h  
#Tw@wfaq)  
T*g:# ^4  
import java.io.*; `d7n?|pD  
import java.net.*; ",6M)3{|c  
UT0){%2@  
%`Z+a.~U  
public class FileSplitterFetch extends Thread { Guz"wY  
1 zw*/dp  
f+8wl!M+6  
String sURL; //File URL wO?{?+I`q  
long nStartPos; //File Snippet Start Position #(An6itl  
long nEndPos; //File Snippet End Position |$?bc3  
int nThreadID; //Thread's ID }gJ(DbnV  
boolean bDownOver = false; //Downing is over ;>n,:355L  
boolean bStop = false; //Stop identical EoK~S\dS  
FileAccessI fileAccessI = null; //File Access interface Fu!RhsW5j  
R(q~ -3~  
/p8dZ
+X  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException phM>.y_  
{ u~A6bK*  
this.sURL = sURL; n2iJ%_zp  
this.nStartPos = nStart; PLK3v4kVM!  
this.nEndPos = nEnd; |yx6X{$k  
nThreadID = id; 0#nPbe,Lj  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 o!)3?  
} J:Qa5MTWp  
%44leINx  
Evedc*z~P  
public void run() B

]Thn  
{ <ZNzVnVA  
while(nStartPos < nEndPos && !bStop) zx)z/
1  
{ Z'.AAOG  
R}!:'^  
vkri+:S3  
try{ E&[{4Ml  
URL url = new URL(sURL); bcE._9@@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x8V('`}j  
httpConnection.setRequestProperty("User-Agent","NetFox"); u)+8S/ )  
String sProperty = "bytes="+nStartPos+"-"; ,Ge
"anO  
httpConnection.setRequestProperty("RANGE",sProperty); {#@W)4)cA  
Utility.log(sProperty); xD~5UER  
Wa{`VS  
Yp^rR }N  
InputStream input = httpConnection.getInputStream(); X:nN0p #  
//logResponseHead(httpConnection); ]QlwR'&j/n  
paCV!tP  
4\8+9b\9"  
byte[] b = new byte[1024]; H[U!%Z  
int nRead; e?
8FN. q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &m)6J'q3k  
{ 'h|DO/X~L  
nStartPos += fileAccessI.write(b,0,nRead); "Q@ronP(~  
//if(nThreadID == 1) +M\`#i\g>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5m&9"T.w  
} :VRNs  
!Prg_6 `  
R{
<kW9!  
Utility.log("Thread " + nThreadID + " is over!"); ^/I 7|u]  
bDownOver = true; YNKHN2E8  
//nPos = fileAccessI.write (b,0,nRead); W$hx,VEy`  
} 5\:^y'g
[  
catch(Exception e){e.printStackTrace ();} 1ySk;;3  
} tE<H|_{L  
} 8lvV4
yb  
4'/nax$Bx;  
E7j(QOf  
//打印回应的头信息 v_+{'F  
public void logResponseHead(HttpURLConnection con) C~,a!qY  
{ yVU^M?`#  
for(int i=1;;i++) #A1%gIw<v2  
{ md)c0Bg8~  
String header=con.getHeaderFieldKey(i); j4gF;-m<  
if(header!=null) JVvs-bK5
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^ Edfv5  
Utility.log(header+" : "+con.getHeaderField(header)); "jeb%k  
else oR)Jznmi}  
break; QO<jI#  
} M'7fO3&|  
} g1/:Q%R,  
d[@X%  
1F5XvQl  
public void splitterStop() y`<
*U;xL  
{ /hr7NT{e%v  
bStop = true; z`.<U{5  
} {fPy=,>Nb  
!j9t*2m[  
G,&<<2{(f;  
} ,`'Qi%O  
hE-h`'ha`  
j@n)kPo,1  
/* l.q&D<
_  
**FileAccess.java $njUXSQ;  
*//文件访问(定位，写) z6KCv(zvB  
package NetFox; QmQ=q7  
import java.io.*; 5MroNr  
$h+1u$po  
J9\Cm!H  
public class FileAccessI implements Serializable{ R|6Cv3:  
eQ$Y0qH1E  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8V~k5#&Ow  
RandomAccessFile oSavedFile; `XJG(Oas\  
long nPos; JYMiLph<  
oK9( /v  
x!?u^  
public FileAccessI() throws IOException 1D7nkAy  
{ oTEL?hw5  
this("",0); yks__ylrl(  
} 'S20\hwt-  
I:E`PZ  
{yBs7[Wn  
public FileAccessI(String sName,long nPos) throws IOException hnffz95  
{ 5u,{6  
oSavedFile = new RandomAccessFile(sName,"rw"); jkQ*D(;p  
this.nPos = nPos; *zaQx+L  
oSavedFile.seek(nPos); gLb`p
Co/  
} ~b(i&DVK  
|+{)_?  
QpF;:YX^3  
public synchronized int write(byte[] b,int nStart,int nLen) .14~J6  
{ $ux,9H'[  
int n = -1; M#ZcY  
try{ hMa]B*o/-  
oSavedFile.write(b,nStart,nLen); seba9y  
n = nLen; $&Gu)4'+  
} n"$jG:AQJ  
catch(IOException e) *}Xf!"I#]N  
{ 3D6RLu
  
e.printStackTrace (); r^2p*nr}  
} 'Oxy$U   
SbcS]H5Sk  
6 [k\@&V-  
return n; \h+
AXs<j  
} 87=&^.~`  
*=) cQeJ  
SfA\}@3  
} rDl*d`He!  
"<6G6?sz  
S&e0u%8mc  
/* Y&`=jDI  
**SiteInfoBean.java FW.7'7G@n  
*/ GXcJ< v  
package NetFox; dMP
c:tJT  
p5Z"|\  
H-WJp<_  
public class SiteInfoBean { N1Ng^aY0  
@>u}eB>Kn  
j >Ht@Wi  
private String sSiteURL; //Site's URL 2$9odD<r  
private String sFilePath; //Saved File's Path {mm)ay|M  
private String sFileName; //Saved File's Name dFRsm0T  
private int nSplitter; //Count of Splited Downloading File k@\ iGqo  
hmvfw:Nq4  
.
@2m07*1  
public SiteInfoBean() `V=N*hv`  
{//nSplitter的缺省值为5 //*fSF
 
//default value of nSplitter is 5 ?*2CpM&l  
this("","","",5); 4<9=5
q]  
} 1uG"f<TsR  
VAWF3  
5BWH-2HsB  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1Y/s%L  
{ ^2+yHw  
sSiteURL= sURL; QXL'^u
O  
sFilePath = sPath; yQU_>_!n  
sFileName = sName; a,xycX:U  
this.nSplitter = nSpiltter; Mx&&0#;r  
b$4"i XSQ  
B&\IGWG(  
} 8u"!dq  
!LggIk1  
JF # # [O  
public String getSSiteURL() C3*gn}[  
{ |L-]fjBbF  
return sSiteURL; +Fuqchjq  
} "|Xk2U  
<Pap
skO>  
]gmexa=(i  
public void setSSiteURL(String value) {wO3<
9  
{ SNfr"2c'h~  
sSiteURL = value; PfreAEv,  
} F5?m6`g?  
M\sN@+  
Rec6c&5_  
public String getSFilePath() [pl'|B  
{ N03HQ
p)g  
return sFilePath; /`f^Y>4gD  
} ]DOX?qI i  
8)O[Aq::  
3 DDML,  
public void setSFilePath(String value) fBalTk;G{U  
{ ;u;#g  
sFilePath = value; >H'4{|  
} &0NFb^8+  
8S%52W|  
f
J/e(t  
public String getSFileName() ])L A42|  
{ Kz>3 ic$I  
return sFileName; MKy[hT:  
} )6+eNsxMlC  
Rniq(FAx  
{.QEc0-  
public void setSFileName(String value) /G5d|P  
{ h<Ft_#|o[  
sFileName = value; XVKfl3'%  
} qW!]co  
ZCB_  
bzX\IrJpOZ  
public int getNSplitter() ^@qvl
%j  
{ ~.UrL(l=  
return nSplitter; oo=Qt(#  
} R}lsnX<  
w:?oTuw  
z)9wXo#~  
public void setNSplitter(int nCount) EI:w aIr  
{ Yc,7tUz#  
nSplitter = nCount; M-[$L XR  
} :_t}QP"  
} G}FIjBE  
.!G94b  
'Er:a?88l  
/* u$-U*r  
**Utility.java e_
V O3"  
*/ RB+N IoQQ|  
package NetFox; :dLAs@z  
aBNZdX]vzO  
~M\I;8ne  
public class Utility { Ay !G1;  
$6CwkM:  
gS:A'@&  
public Utility() V^\8BVw  
{ 7f~Sf  
^`G`phd$  
Tp0b
S  
} ] Puy!Q  
SL,p36N  
//线程睡眠 :<Fe  
public static void sleep(int nSecond) I8QjKI (  
{ a\%xB >LX  
try{ U-:ieao@  
Thread.sleep(nSecond); }=|!:kiE  
} eQVZO>)P1+  
catch(Exception e) YG8>czC  
{ sg8/#_S1i  
e.printStackTrace (); JICawj:I  
} /l{&iLz[  
} ?]rPRV
  
Q43|U4a  
//日志 1-PoZ[p-R  
public static void log(String sMsg) :=9]c17=  
{ 3b YCOqG  
System.err.println(sMsg); Nk[2n
yeO>  
} \3Q&~j  
(n1Bh~R^
 
5~
.ZlGd  
public static void log(int sMsg) ;Efcw[<  
{
KvQ,;A  
System.err.println(sMsg); t |W)  
} cE iu)2*e  
} "C?5f]T  
~Z ~v  
Wy]^Ub gW  
/* L'i-fM[#  
**TestMethod.java jxgj,h"}9`  
*/ "&Qctk`<P  
package NetFox; K={qU[_O  
YHV-|UNF  
]ALc;lb-}  
public class TestMethod { Y`6rEA0  
w>xV  
RE3Z%;'  
public TestMethod() iP3Z  
{ ///xx/weblogic60b2_win.exe Dbx~n#nG  
try{ D~K;~nI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); s]27l3)B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jY!ZkQsVe  
SiteFileFetch fileFetch = new SiteFileFetch(bean); k /EDc533d  
fileFetch.start(); ~:sE:9$z  
} %1M
cD{  
catch(Exception e){e.printStackTrace ();} > ^[z3T  
Ja^ 5?Ar|  
*j)M]  
} JbQZ!+  
(hZ:X)E>  
d}0qJoH4  
public static void main(String[] args) "4}wnu6/  
{ /nB'kg[h\  
new TestMethod(); aSnp/g  
} M23&<}Q8  
} ;lfWuU%R  
点击下载更多相关资料