http断点续传简单实现（java)

/* #!# X3j  
**SiteFileFetch.java j88sE MZ  
*/ FH`&C*/F0Y  
package NetFox; #q.G_-H4J@  
import java.io.*; @6'E8NFl  
import java.net.*; IkNt! 2s_  
pY#EXZ#   
Q.dy $`\  
public class SiteFileFetch extends Thread { BM~niW;k  
h]$?~YE  
chzR4"WZFt  
SiteInfoBean siteInfoBean = null; //文件信息Bean G<6grd5PP  
long[] nStartPos; //开始位置 D#}Yx]Q1  
long[] nEndPos; //结束位置 dU^<7 K:S  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4 xzJql  
long nFileLength; //文件长度 #gJ~ {tA:  
boolean bFirst = true; //是否第一次取文件 ~U6YN_W  
boolean bStop = false; //停止标志 HTyF<K  
File tmpFile; //文件下载的临时信息 U*"cf>dB(  
DataOutputStream output; //输出到文件的输出流 >=:T ZU  
A=
]F_  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） UZXcKl>u  
public SiteFileFetch(SiteInfoBean bean) throws IOException f.)F8!!  
{ C_ZD<UPA\  
siteInfoBean = bean; RXS|-_$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @"Fp;Je\bN  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Zbh]SF{3F  
if(tmpFile.exists ()) (,c?}TP  
{ :_,]?n  
bFirst = false; yZ)aKwj%U  
read_nPos(); B~g05`s  
} >fA@tUQB  
else wW! r}I#  
{ tDHHQ  
nStartPos = new long[bean.getNSplitter()]; S*m`'  
nEndPos = new long[bean.getNSplitter()]; L[Yp\[#-q  
} [aZ v?Z  
'BdmFKy1  
u$=ogp=0  
K[>@'P}y  
} 0ij~
e<  
K&IrTA j}  
)cqDvH  
public void run() %X,B-h^  
{ <
_a70"i  
//获得文件长度 Lr}b,  
//分割文件 :&0yf;>v  
//实例FileSplitterFetch K l0tyeT  
//启动FileSplitterFetch线程 <+-Yh_D  
//等待子线程返回 3ES[ N.V#  
try{ 7l#2,d4  
if(bFirst) "^ 6lvZP(  
{ '
)u5l  
nFileLength = getFileSize(); 5hH6G  
if(nFileLength == -1) 4$zFR}f  
{ 0fPHh>u  
System.err.println("File Length is not known!"); 0gOrW=  
}
yLgKS8b  
else if(nFileLength == -2) B=gsd0^]  
{ 29iIG 'N  
System.err.println("File is not access!"); ( ztim  
} Z]aK'  
else /y9J)lx  
{ G V:$;  
for(int i=0;i<nStartPos.length;i++) si^4<$Nr%j  
{ $vTAF-~Ql  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); eN]>l  
} s!hI:$J.  
for(int i=0;i<nEndPos.length-1;i++) ne"?90~  
{ O@r.>  
nEndPos = nStartPos[i+1]; {7=WU4$  
} #6N+5Yx_[  
nEndPos[nEndPos.length-1] = nFileLength; LmX
F`Y$  
} o=-Vt,2{  
} 0eqi1;$b]  
pFsCd"zv  
UR1JbyT  
//启动子线程 dSe8vA!)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /UpD$,T|^|  
for(int i=0;i<nStartPos.length;i++) 5@+4
 
{ )+n,5W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y^f94s:2S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O}K
_l1  
nStartPos,nEndPos,i); MegE--h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 80?6I%UB<  
fileSplitterFetch.start(); &o
*s !u  
} IpWy)B>Fl3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s&dO/}3uR]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 29Gwv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", aNE9LAms  
nEndPos = " + nFileLength); k_D4'(V:b  
// fileSplitterFetch[nPos.length-1].start(); %RQC9!  
~A`&/U  
gDQkn {T.%  
//等待子线程结束 bBUbw*DF)  
//int count = 0; bp]^EVx  
//是否结束while循环 ORGv)>C|  
boolean breakWhile = false; q&X
CX$N  
`fBG~NDw  
OUEI~b1  
while(!bStop) Sl3KpZ  
{  4%g6_KB  
write_nPos(); FI
]P<)*r  
Utility.sleep(500); W@I 02n2H  
breakWhile = true; hLb;5u&!kW  
L`9TB"0R+  
"?apgx 6  
for(int i=0;i<nStartPos.length;i++) '[Mlmgc5  
{ T-4/d5D[  
if(!fileSplitterFetch.bDownOver) $ A-+E\vQ@  
{ &/Eg2  
breakWhile = false; ;i<$7MR.e  
break; }J
RP,YNh  
} m7$8k@r  
} Jy \2I{I'  
if(breakWhile) iO!27y  
break; SArfczoB  
w3^NL(>  
TT'Ofvdc  
//count++; Ne3R.g9;Z  
//if(count>4) pv$mZi4i  
// siteStop(); gRBSt M&hU  
} 6}ce1|mkg/  
<&
4nOt  
"mP&8y9F  
System.err.println("文件下载结束！"); "r u]?{v  
} sU\c#|BSC"  
catch(Exception e){e.printStackTrace ();} ,eR8~(`=  
} R)ERxz#  
FY$fV"s  
ujU=JlJ7dl  
//获得文件长度 /QQ8.8=5  
public long getFileSize() l :/&E 6 9  
{ C)NC&fV  
int nFileLength = -1; ?a S%  
try{ dd]?9  
URL url = new URL(siteInfoBean.getSSiteURL()); mw_ E&v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nSS>\$  
httpConnection.setRequestProperty("User-Agent","NetFox"); d')-7C  
!BDUv(  
BT]ua]T+  
int responseCode=httpConnection.getResponseCode(); *l{yW"Su  
if(responseCode>=400) L'lF/qe^  
{ Cezh l  
processErrorCode(responseCode); %?bcT[|3  
return -2; //-2 represent access is error wJgX/W  
} P.djd$#  

|g%mP1O  
I]h-\;96  
String sHeader; h35Hu_c&  
2#3^skj  
UfO7+_2  
for(int i=1;;i++) b;#\~(a  
{ 5!Bktgk.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); IS BV%^la|  
//Utility.log(in.readLine()); w1r$='*I  
sHeader=httpConnection.getHeaderFieldKey(i); BYi)j6"  
if(sHeader!=null) XF|WCZUnY%  
{ q@n^ZzTx  
if(sHeader.equals("Content-Length")) 6"U8V?E  
{ JS2nXs1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3NIUW!gr  
break; +E/y ~s  
} ; dd Q/  
} Gs dnf 7  
else QK; T~ _k  
break; Z)pz,  
} PmR*}Aw  
} w\w(U  
catch(IOException e){e.printStackTrace ();} O oSb>Y/4  
catch(Exception e){e.printStackTrace ();} /\Z J
 

wvMW|  
K=?VDN  
Utility.log(nFileLength); ,Q/Ac{C  
?m0IehI  
@ {#mpDX  
return nFileLength; hXn3,3f3oZ  
} rR,2UZR  
uS+k^ #  
!:CJPM6j3  
//保存下载信息（文件指针位置） nmFC%p)4  
private void write_nPos() }P9Ap3?  
{ K93p"nHN  
try{ !}KqB8;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); k+^'?D--'P  
output.writeInt(nStartPos.length); ~D[?$`x:  
for(int i=0;i<nStartPos.length;i++) ' GG=Ebt  
{ ;heHefbvvd  
// output.writeLong(nPos); !@A#=(4R4  
output.writeLong(fileSplitterFetch.nStartPos); Ucdj4[/,h  
output.writeLong(fileSplitterFetch.nEndPos); {@Y
 
} 7^*"O&y_al  
output.close(); v$wBxCY  
} <3okiV=ox  
catch(IOException e){e.printStackTrace ();} i/So6jW  
catch(Exception e){e.printStackTrace ();} jJZgK$5+  
} lb*8G  

fyWO  
<?Wti_ /M  
//读取保存的下载信息（文件指针位置） LjB;;&VCn  
private void read_nPos() !T,AdNa8  
{ sZ<9A Xk-E  
try{ 6t'l(E +  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -fI@])$9J  
int nCount = input.readInt(); TXXy\$  
nStartPos = new long[nCount]; RW$:9~  
nEndPos = new long[nCount]; f:B>zp;N  
for(int i=0;i<nStartPos.length;i++) ,m<H-gwa  
{ SLfFqc+n0  
nStartPos = input.readLong(); )~6zYJ2  
nEndPos = input.readLong(); NS)}6OI3~"  
} &sXRN&Fp  
input.close(); dsx]/49<  
} <"D=6jqZ  
catch(IOException e){e.printStackTrace ();} 2F#q I1  
catch(Exception e){e.printStackTrace ();} Sn4[3JV$l  
} hwN?/5  
C:8_m1Y{  
3@Z#.FV~C[  
private void processErrorCode(int nErrorCode) 
1?*  
{ "P-lSF?T  
System.err.println("Error Code : " + nErrorCode); 7pA/   
} 38DT2<qC  
Eodn/  
jn >d*9u  
//停止文件下载 Uo12gIX  
public void siteStop() Io4(f  
{ @~c6qh  
bStop = true; ##Q/I|  
for(int i=0;i<nStartPos.length;i++) =0;}K@(J  
fileSplitterFetch.splitterStop();  c gz
wx  
)*;zW!H  

3p2P= T  
} ")O`mXg-  
} #_Z$2L"U  
//负责部分文件的抓取 i wxVl)QL  
**FileSplitterFetch.java :ISMPe3'  
*/ T,xPSN2A*  
package NetFox; wn_b[tdxq  
K
7Rpr.p  
oI)GKA_Ng7  
import java.io.*; kn)t'_jC  
import java.net.*; A;\7|'4  
ZxV"(\$n  
MX4]Vpv  
public class FileSplitterFetch extends Thread { E9?phD  
\AL f$88>@  
O+}qQNe<  
String sURL; //File URL I;VuW  
long nStartPos; //File Snippet Start Position lEHzyh}2k  
long nEndPos; //File Snippet End Position J!'@Bd  
int nThreadID; //Thread's ID mUS_(0q  
boolean bDownOver = false; //Downing is over |FD}e)  
boolean bStop = false; //Stop identical N2.AKH  
FileAccessI fileAccessI = null; //File Access interface Og=*R6i  
+f*OliMD  
WTImRXK4  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Dfq(Iv  
{ 3~nnCR[R  
this.sURL = sURL; GA7}K:LP'k  
this.nStartPos = nStart; v1a6?-  
this.nEndPos = nEnd; 5M9 I,  
nThreadID = id; 3%.#}O,(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'v]u#/7a  
} \:'%9 x  
,+~rd4a  
&\apwD  
public void run() @+atBmt  
{ _`64gS}^  
while(nStartPos < nEndPos && !bStop) pABs!A`N  
{ Oft4-4$E  
]E]2o  
V+I|1{@i0  
try{ *N{emwIq  
URL url = new URL(sURL); #v<QbA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z*-g[8FO  
httpConnection.setRequestProperty("User-Agent","NetFox"); UQB"v3Z  
String sProperty = "bytes="+nStartPos+"-"; P(t[ eXe  
httpConnection.setRequestProperty("RANGE",sProperty); tK&'<tZh  
Utility.log(sProperty); LBF 1;zjK  
l x,"EOP  
meOMq1  
InputStream input = httpConnection.getInputStream(); eds26(  
//logResponseHead(httpConnection); rk)##)  
+[5.WC7J  
ss5m/i7  
byte[] b = new byte[1024]; Yv:55+e!|  
int nRead; v%f
u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;A#`]-i C  
{ =zyC-;r!  
nStartPos += fileAccessI.write(b,0,nRead); byv[yGa`  
//if(nThreadID == 1) W3iZ|[E;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?(R]9.5S  
} Y-7^o@y  
1 5A*7|  
A'2w>8  
Utility.log("Thread " + nThreadID + " is over!"); -YsLd 9^4  
bDownOver = true; ATR!7i\|  
//nPos = fileAccessI.write (b,0,nRead); 8>7&E-  
} 9'r:~O  
catch(Exception e){e.printStackTrace ();} (&!NC[n,  
} {l |E:>Q2  
} up'Tit  

|^A;&//  
_)\c&.p]f  
//打印回应的头信息 3;a<_cE*@  
public void logResponseHead(HttpURLConnection con) y
rR1[aT  
{ zToq^T  
for(int i=1;;i++) 8
O Soel  
{ p ZZc:\fJ  
String header=con.getHeaderFieldKey(i); s M+WkN}{  
if(header!=null) &B|D;|7H  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VZ\B<i  
Utility.log(header+" : "+con.getHeaderField(header)); *W kIq>  
else nB!&Zq  
break; f aLtdQi  
} ]niJGt  
} D_x+
:1(  
#y%!\1M/:A  
^.>jGI%rB  
public void splitterStop() Yh>]-SCw  
{ .B\5OI,]  
bStop = true; U{VCZ*0cj  
} TYQwy*  
AGbhJ=tB
 
LU9A#  
} #b~JDO(  
bP^Je&nS*  
:duo#w"K  
/* B` k\EL'  
**FileAccess.java KhMSL  
*//文件访问(定位，写) =Jym%m  
package NetFox; T,VY.ep/  
import java.io.*; ObiT-D?)g  
&0`) Q
 
3%E74 mOcD  
public class FileAccessI implements Serializable{ qcN'e.A  
-*XCxU'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p8]68!=W\F  
RandomAccessFile oSavedFile; B4mR9HMh  
long nPos; Q^#;
WASi  
+mp@b942*  
,j$Vvz  
public FileAccessI() throws IOException !Uq^7Mw  
{ di>cMS 4 c  
this("",0); fF V!)Zj  
} 8f3vjK'  
 0gfA#|'  
Ba/Yl  
public FileAccessI(String sName,long nPos) throws IOException qIAoA.  
{ Sx8OhUyux  
oSavedFile = new RandomAccessFile(sName,"rw"); oD$J0{K6  
this.nPos = nPos; <Ce2r"U1e  
oSavedFile.seek(nPos); 2!$gyu6bpG  
} 7Ddaf>  
=-}[^u1  
m2v'WY5u  
public synchronized int write(byte[] b,int nStart,int nLen) QJ7L7S  
{  z~>pVs
  
int n = -1; Y14W?|KOB  
try{ WuZ/C_  
oSavedFile.write(b,nStart,nLen); pf_mf.  
n = nLen; Z>^pCc\lH  
} MKWyP+6`  
catch(IOException e) f0BdXsV#g  
{ _z1(y}u}  
e.printStackTrace (); ]TyisaT  
} )u
qA(R>  
Co3:*nbRv  
W[^qa5W<FB  
return n; B0ndcB-  
} ~fo6*g:f1  
;JRs?1<='  
A4]s~Ur  
} zD?K>I=  
Jzp#bgq}|  
bpxeznz  
/* FSRj4e1y1  
**SiteInfoBean.java G2^et$<{uU  
*/ VV9_`myN7  
package NetFox; A+UU~?3y  
Zw~
+Pb  
w$u3W*EoU^  
public class SiteInfoBean { wW%4d  
%bdjBa}  
(k|_J42[  
private String sSiteURL; //Site's URL HWVtop/  
private String sFilePath; //Saved File's Path ~jb"5CX  
private String sFileName; //Saved File's Name MX ;J5(Ae  
private int nSplitter; //Count of Splited Downloading File 5A4&+rdU  
v$ub~Q6W  
d` [HT``  
public SiteInfoBean() (X?/"lC)  
{//nSplitter的缺省值为5 3q?\r` a  
//default value of nSplitter is 5 =2 *rA'im  
this("","","",5); :(H>2xS,s  
} yZWoN&  
>B>CB3U  
Vy|6E#U  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  HyR!O>  
{ 41_SRh7N  
sSiteURL= sURL; E(i[o?  
sFilePath = sPath; }E7:ihy  
sFileName = sName; k}#;Uy=5  
this.nSplitter = nSpiltter; ymNnkFv  
\fjMc }'  
FPJd|  
} jU5}\o
P@  
W'on$mB5<  
3<=G?of  
public String getSSiteURL() E.iSWAJ(w  
{ ?}B:  
return sSiteURL; oY=q4D  
} _A~4NW{U7  
kZ=s'QRgL  
OK{xuX8u  
public void setSSiteURL(String value) C8L'si  
{ x{&
w?ng  
sSiteURL = value; @p|$/Z%R,  
} ^Eo=W/   
PG]%Bv57  
Zx$ol;Yd  
public String getSFilePath() Ea(,aVlj  
{ O MX-_\")  
return sFilePath; <vUVP\u~$  
} ^bL
RVp1  
8/"fWm
/  
')N{wSM9Ft  
public void setSFilePath(String value) 2
:LHy[{5  
{ d` Sr4c  
sFilePath = value; eVl'\aUd  
} 'r\ V.4  
5ZY)nelc  
Urgtg37  
public String getSFileName() 4c+$%pq5  
{ ="d*E/##  
return sFileName; pDhse2  
} g`>og^7g  
:L 3&FA  
J# kl 7
 
public void setSFileName(String value) 1h7+@#<:a  
{ A!63p$VT;  
sFileName = value; _3Cn{{ A0  
} &5t :H 8b  
yE} dj)wd  
:h,`8 Di  
public int getNSplitter() gLsU:aeCT  
{ :|1.seLQ  
return nSplitter; ]h9!ei [  
} !rhk $L  
~np,_yI  
8Q)@  
public void setNSplitter(int nCount) \/|)HElKR  
{ z}Jr^>  
nSplitter = nCount; =xianQ<lK  
} rx:z#"?I  
} 4@;-%H&7  
OJ4SbI  
~svO*o Wa  
/*
+2C?9:bH  
**Utility.java +{53a_q  
*/ {0YAzZ7  
package NetFox; OVk~N)  
IK^~X{I?  
(ozb%a#B  
public class Utility {
nF)uTk  
?nKF6f  
)$x_!=@1  
public Utility() 'YSuQP>  
{ !~-6wN"k  
jQj,q{eA  
v$w++3H  
} !Ngw\@f  
q\9d6u=Gm  
//线程睡眠 `&$B3)Eb  
public static void sleep(int nSecond) 7k=fZ$+O  
{ mE#nU(+Ta  
try{ yy(A(}  
Thread.sleep(nSecond); Ov9Q?8KzM  
} XT@Mzo49z\  
catch(Exception e) >[a<pm!  
{ RM*f|j  
e.printStackTrace (); W$?e<@  
} D>wZ0p b-  
} %kU'hzLg  
.gYt0raSY  
//日志 ~S(^T9R  
public static void log(String sMsg) yi!`V.  
{ FEm=w2  
System.err.println(sMsg); rj
H`  
} Qu~*46?0  
-)w]a{F  
'
dt\db5p  
public static void log(int sMsg) mrZ`Lm#>pS  
{ 9XV^z*E(J  
System.err.println(sMsg); 7!2 HNg  
} CB*/ =Y  
}  U w Eiz  
KAb(NZK  
6f]rQ9  
/* .RRlUWu  
**TestMethod.java ^@.G,u  
*/ Q_}/ Pn$1  
package NetFox; qa!RH]B3  

wRVD_?  
mtw9AoO  
public class TestMethod { ,d 7
Z  
FDLd&4Ex  
5}a"?5J^  
public TestMethod() ]C *1
0S`  
{ ///xx/weblogic60b2_win.exe SFO&=P:U  
try{ cgyo_ k  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &`@M8-m#F  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); pT=2e&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *bZ\@Qm  
fileFetch.start(); exphe+b  
} YsAF{  
catch(Exception e){e.printStackTrace ();} V.,bwPb{9  
V} bM!5 H  
2z-$zB<vyw  
} t:9 ZCu ay  
K^ 6+Ily  
cV]y=q6  
public static void main(String[] args) ~V$ f#X  
{ BE%Z\E[[m  
new TestMethod(); 2nx9#B*/T  
} aQh?}=da  
} 0P9Wy
!f7  
点击下载更多相关资料