http断点续传简单实现（java)

/* N R c4*zQJ  
**SiteFileFetch.java <+QdBp'd;
 
*/ oN032o?S  
package NetFox; 6]7c
sOE  
import java.io.*; 'rhgM/I  
import java.net.*; 'jt7H{M  
uw mN!!TS  
1Vpti4OmU  
public class SiteFileFetch extends Thread { rC8p!e.yL  
#-yCR  
Lx,=Up.  
SiteInfoBean siteInfoBean = null; //文件信息Bean |k.'w<6mb9  
long[] nStartPos; //开始位置 ]p!{   
long[] nEndPos; //结束位置 xXJ*xYn"}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 xsa`R^5/c  
long nFileLength; //文件长度 ^hLr9k   
boolean bFirst = true; //是否第一次取文件 _LJF:E5L  
boolean bStop = false; //停止标志 2yA)SGri  
File tmpFile; //文件下载的临时信息 ?V6,>e_+  
DataOutputStream output; //输出到文件的输出流 #E]K*mE'  
#/>TuJc  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） R4p Pt  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]-gyXE1.r  
{ z0[@O)Sj  
siteInfoBean = bean; KF(H >gs  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4aO/^Hl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =:rg1wo"c  
if(tmpFile.exists ()) $tZ {>!N  
{ 8lusKww  
bFirst = false; SAP/jD$5]>  
read_nPos(); a=2.Y?  
} Vk{
;g  
else zYzV!s2^  
{ P j   
nStartPos = new long[bean.getNSplitter()]; C|ZPnm>f30  
nEndPos = new long[bean.getNSplitter()]; G)amng/  
}
wn"}<ka  
"BQnP9  
nCYkUDnZ  
C8m9H8Qm  
} b,'O|s]"Sc  
I}PI  
6H|1IrG  
public void run() >jt2vU@t.  
{ v#,queGi  
//获得文件长度 k8D_  
//分割文件 (d_z\U7l  
//实例FileSplitterFetch /l$enexSt  
//启动FileSplitterFetch线程 /DAR'9@h  
//等待子线程返回 ,@ '^3u  
try{ G*9(O:  
if(bFirst) ! I:N<  
{ kX8C'D4 gX  
nFileLength = getFileSize(); Yw|v5/>  
if(nFileLength == -1) hl1IG !  
{ 8^>qor.]M  
System.err.println("File Length is not known!"); /2p*uv}IP  
} &N^j }^ Z  
else if(nFileLength == -2) = wz}yfdrC  
{ g~DuK|
+  
System.err.println("File is not access!"); |.k'?!  
} g*YDgY  
else J5{;+ysUMl  
{ ?c#s}IH  
for(int i=0;i<nStartPos.length;i++) `w!XO$"]Z  
{ c5ij2X|I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Y5aG^wE[:  
} E0ED[d,  
for(int i=0;i<nEndPos.length-1;i++) ^8 VW$}  
{ KW:N 6w  
nEndPos = nStartPos[i+1]; u''Ce`N  
} Ll]5u~  
nEndPos[nEndPos.length-1] = nFileLength; CXq[VYM&X  
} 4\n ~  
} >ai
,6!  
*L^W[o  
Da-Lf2qT9  
//启动子线程 x?L[*N_ml  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; FJ3S  
for(int i=0;i<nStartPos.length;i++) eIvZhi  
{ phy}Hk/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), av'm$I|O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), qHk{5O3  
nStartPos,nEndPos,i); w~@"r#-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2 5 \S>  
fileSplitterFetch.start(); .8YxEnXw)(  
} Uj5
-x%~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h4]^~stI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); iwF_'I$#N  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'WW:'[Syn'  
nEndPos = " + nFileLength); @} Ig*@  
// fileSplitterFetch[nPos.length-1].start(); cQEUHhRg!  
FI^Wh7J  
CV0id&Nv  
//等待子线程结束 _V"0g=&Hc  
//int count = 0; ]?}>D?5  
//是否结束while循环 VlV X  
boolean breakWhile = false; h%EeU 3  
S70#_{  
Jj=qC{]  
while(!bStop) KZ5%q.  
{ }PI:O%N;  
write_nPos(); >/n];fl>8  
Utility.sleep(500); 8"&!3_  
breakWhile = true; d2
7q,2f!  
f\2IKpF2  
4kL6aSqT  
for(int i=0;i<nStartPos.length;i++) 72;'
8  
{ %RD\Sb4YV  
if(!fileSplitterFetch.bDownOver) BHr,jC  
{ w'TAM"D`  
breakWhile = false; %M96m  
break; -m^-p  
} ) ^En  
} rD}g9?ut  
if(breakWhile) T 6D+@i  
break; mOJdx-q?r  
BeUyt  
~9]vd|  
//count++;  }#m9Q[  
//if(count>4) 5|rBb[  
// siteStop(); n.@HT"  
} h~#iGs  
#&.Znk:@.f  
Ll KO(Q{"  
System.err.println("文件下载结束！"); 4 
{M   
} 5{HF'1XgZ*  
catch(Exception e){e.printStackTrace ();} JRB6T_U  
} ]$g07 7o  
@ZISv'F  
)+L|<6JXA  
//获得文件长度  Gsh9D  
public long getFileSize() 3S3 a|_+%  
{ ^0zfQu+!  
int nFileLength = -1; 5'set?  
try{ |&4A"2QN  
URL url = new URL(siteInfoBean.getSSiteURL()); 7L
#)yY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); no+m.B  
httpConnection.setRequestProperty("User-Agent","NetFox"); jj`#;Y  
li[[AAWVm  
p<
r^{y  
int responseCode=httpConnection.getResponseCode(); ^t3>Z|DiB^  
if(responseCode>=400) k@7#8(3  
{ w>
B}w  
processErrorCode(responseCode); 2q[pOT'k  
return -2; //-2 represent access is error wS=vm}}u  
} Gor9&aJ1  
$2W#'_K+  
;87PP7~  
String sHeader; 5$ik|e^:y  
u4hn9**a1  
o%'1=d3R1Q  
for(int i=1;;i++) YXp\C"~g  
{ vN(~}gOd\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G/JGb2I/7|  
//Utility.log(in.readLine()); uBts
?02  
sHeader=httpConnection.getHeaderFieldKey(i); bkdXBCBx?  
if(sHeader!=null) 5ih>x3S1/  
{ +[ ?!@)  
if(sHeader.equals("Content-Length")) ` +YtTK  
{ <Z.`X7]Uk  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); hj1;f<' U  
break; d
Co)
en  
} UnDCC_ud  
} p l^;'|=M  
else ,6]ID1o:y  
break; YH58p&up  
} %fF,Fnf2  
} fuj9x;8X0  
catch(IOException e){e.printStackTrace ();} L-- t(G  
catch(Exception e){e.printStackTrace ();} r]Hrz'C`  
,LwinjHA*  
,<Cl^ ^a,  
Utility.log(nFileLength); -,/7u3  
0y|1@CS  
';G/,wB?`  
return nFileLength; 4AL,=C3  
} PV\J] |d,%  
~0,v Q   
c!HGiqp  
//保存下载信息（文件指针位置） oOprzxf"+Z  
private void write_nPos() *m
]Y6  
{ ,~cK]!:>s  
try{ 7l7VT
?<:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &/[MWQ  
output.writeInt(nStartPos.length); ?8$`GyjS  
for(int i=0;i<nStartPos.length;i++) [GbrKq(  
{ jS]Saqd  
// output.writeLong(nPos); Xj]9/?B?  
output.writeLong(fileSplitterFetch.nStartPos); \ C:Gx4K  
output.writeLong(fileSplitterFetch.nEndPos); I+Fy)=DO9  
}  p[&Jl  
output.close(); 9+y&&;p  
} vKnZ==B  
catch(IOException e){e.printStackTrace ();} *JImP9SE  
catch(Exception e){e.printStackTrace ();} =xkaF)AW&v  
} PW@ :fM:q  
[>`.,k  
W'9{2h6u(  
//读取保存的下载信息（文件指针位置） TAh'u|{u2  
private void read_nPos() H,c1&hb/w  
{ *-*V>ntvT$  
try{ nZ=[6?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >3g`6d  
int nCount = input.readInt(); hAUP#y@:H:  
nStartPos = new long[nCount]; W\j'8^kI9  
nEndPos = new long[nCount];
I wj[ ^  
for(int i=0;i<nStartPos.length;i++) L[44D6Vg  
{ E[t[R<v,P!  
nStartPos = input.readLong(); .feB VRg  
nEndPos = input.readLong(); ;m] nl_vg  
} W2h*t"5W  
input.close(); 78]*Jx>L  
} [&~x5l 8\C  
catch(IOException e){e.printStackTrace ();} 7}qxWz  
catch(Exception e){e.printStackTrace ();} |}^u<S8X  
} W0x9^'=s\  
v8)wu=u  
Ib{#dhV  
private void processErrorCode(int nErrorCode) 8Mtd}{Fw*  
{ hTO5*5]0zP  
System.err.println("Error Code : " + nErrorCode); m^BXLG:b  
} 5vD\?,f E  
h)s
T37  
'r=2f6G>cP  
//停止文件下载 W8`6O2  
public void siteStop() hwk] ;6[  
{
M%54FsV  
bStop = true; X`<z5W] !  
for(int i=0;i<nStartPos.length;i++) \="U|LzG  
fileSplitterFetch.splitterStop(); s8A"x`5(  
^%%Rf  
"&XhMw4  
} Gfx!.[Y  
} \$Ky AWrZi  
//负责部分文件的抓取 DMA7eZf'Hv  
**FileSplitterFetch.java %npLgCF  
*/ ({Yfsf,  
package NetFox; OS%[SHs  
%gn@B2
z  
Xqe Qj}2kA  
import java.io.*; Y\<w|LkD8  
import java.net.*; U5ph4G  
VQf^yq  
Uth+4A
q  
public class FileSplitterFetch extends Thread { vC&0UNe$  
Q2oo\  
8MW-JZ  
String sURL; //File URL 5o{U$  
long nStartPos; //File Snippet Start Position dVq9'{[3  
long nEndPos; //File Snippet End Position Jo qhmn$j  
int nThreadID; //Thread's ID )Dms9:  
boolean bDownOver = false; //Downing is over KiMlbF.~V  
boolean bStop = false; //Stop identical *eD[[HbKX  
FileAccessI fileAccessI = null; //File Access interface l %zbx"%x  
iiuT:r  
x]Nx,tt  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2OI 0B\  
{ 0 -M i q  
this.sURL = sURL; xc'uCbH  
this.nStartPos = nStart; |j/Y#.k;{0  
this.nEndPos = nEnd; 1Q^u#m3  
nThreadID = id; F~fN7<9R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H
t43G_.j  
} }X])05
5S  
LIJ#nb  
!iHC++D  
public void run() 'rXf  
{ N?S;v&q+  
while(nStartPos < nEndPos && !bStop) 'G[G;?F  
{ l`6.(6  
5`}za-  
O)R}|  
try{ $uwz`N:  
URL url = new URL(sURL); b'FTyi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m0W3pf  
httpConnection.setRequestProperty("User-Agent","NetFox"); lZkJ<*z#  
String sProperty = "bytes="+nStartPos+"-"; EGFP$nvq  
httpConnection.setRequestProperty("RANGE",sProperty); (VkO[5j  
Utility.log(sProperty); r1.zURY  
}#~E-N3x  

v 9G~i  
InputStream input = httpConnection.getInputStream(); a`9pHH:7Q  
//logResponseHead(httpConnection); Nz"K`C>/  
%c$|.TkX  
`o9:6X?RA  
byte[] b = new byte[1024]; }/tf^@  
int nRead; 2>.b~q@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) mo tW7|p.e  
{ ZL
VgK@l  
nStartPos += fileAccessI.write(b,0,nRead); G{|"WaKW  
//if(nThreadID == 1) 
3KeY4b!h  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,. ht ~AE  
} Z9h4 pd  
 $AZ=;iP-  
g;q.vHvsc"  
Utility.log("Thread " + nThreadID + " is over!"); @b2?BSdUp  
bDownOver = true; 1Xh@x  
//nPos = fileAccessI.write (b,0,nRead); T.QJ#vKO0  
} "Ar|i8^G3  
catch(Exception e){e.printStackTrace ();} S^i8VYK,C5  
} K5<2jl3S  
} it>Bf;  
y% !.:7Y  
qxyY2&  
//打印回应的头信息 3z#>1HD$  
public void logResponseHead(HttpURLConnection con) ut]&3f''  
{ iBWEZw)  
for(int i=1;;i++) ME)='~E  
{ lHliMBSc  
String header=con.getHeaderFieldKey(i); Bn.R,B0PL  
if(header!=null) E@Ewx;P5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <)_#6)z:  
Utility.log(header+" : "+con.getHeaderField(header)); xU{0rM"  
else ,'<N
yA><  
break; ,T^A?t  
} DqI"
B  
} "9X(.v0ze  
Jv%)UR.]  
[EVyCIcY,h  
public void splitterStop() C>-}BeY!  
{ S,,Wb&A$  
bStop = true; iB~dO @  
} S<*1b 6%D  
+?QHSIQo  
sVnq|[ /  
} W<O/LHKHdn  
<Vh5`-J  
<Nloh+n=  
/* t"~X6o|R  
**FileAccess.java 1 K^-tms  
*//文件访问(定位，写) {65YTt%  
package NetFox; ZOppec1D  
import java.io.*; 9qzHy}A  
A;^{%S  
39~WP$GM  
public class FileAccessI implements Serializable{ t82*rCIB{  
z0YL,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >$3 =yw%  
RandomAccessFile oSavedFile; R+U*]
5~R  
long nPos; ,#^2t_c/  
PVN`k, 4  
l Ny<E!0  
public FileAccessI() throws IOException nc.P  
{ xvWP^Qkb  
this("",0); ,WoB)V.{(  
} "79b>  
>r4BI}8SK<  
u2':~h?l  
public FileAccessI(String sName,long nPos) throws IOException c*(=Glzn  
{ V6Of(;r  
oSavedFile = new RandomAccessFile(sName,"rw"); !0Ak)Q]e'  
this.nPos = nPos; R$it`0D4o  
oSavedFile.seek(nPos); 6@d/k.3p  
} Y'}c$*OkI  
:4\_upRE  
FELW?Q?k  
public synchronized int write(byte[] b,int nStart,int nLen) ,&@FToR  
{ SM<qb0
 
int n = -1; ,[_)BM  
try{ G 8tK"LC  
oSavedFile.write(b,nStart,nLen); !_dW `  
n = nLen; {=Py|N\\t  
} '1G0YfG}n  
catch(IOException e) hig t(u  
{ Mu$q) u  
e.printStackTrace (); gaU^l73,C  
} I'<sJs*p  
5mZ9rLn  
CWD $\KG  
return n; 3m~3l d  
} *JWPt(bnI  
cvpZF5mL]U  
Sx_j`Cgy  
} n@oSLo`k,`  
~(cqFf  
MGo`j:0  
/* %7Gq#rq  
**SiteInfoBean.java {PL,3EBG  
*/ 7=
A @P  
package NetFox; tg~7^(s  
)_l(WF.  
'E\qqE[;  
public class SiteInfoBean { Ml_!
)b  
"x
3!F&  
?J"Y4,{  
private String sSiteURL; //Site's URL `K2vG`c  
private String sFilePath; //Saved File's Path fKs3H?|  
private String sFileName; //Saved File's Name CZCVC (/u  
private int nSplitter; //Count of Splited Downloading File (<|1/^~=  
q}&+{dN\1  
You~ 6d6Om  
public SiteInfoBean() L[:M[,?=`  
{//nSplitter的缺省值为5 .4=A:9  
//default value of nSplitter is 5 d%1Vby  
this("","","",5); ;tZ8Sh)  
} {Q0DHNP(G  
Bf,
}mCq  
gdqED}v  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) k{\a_e`  
{ 1n$  
sSiteURL= sURL; 9H%
ixBnM  
sFilePath = sPath; =mxj2>,&  
sFileName = sName; "W"r0"4
 
this.nSplitter = nSpiltter; *MN("<A_  
t\ 9Y)d  
}sfvzw_  
} M !rw!,g  
G?+]BIiL  
EmV ZqW  
public String getSSiteURL() 9lX+?m~ ~  
{ \@7 4I7  
return sSiteURL; &KeD{M%  
} ZD8E+]+  
b$B-LvHd1  
Z Mf,3  
public void setSSiteURL(String value) * \tR  
{ N)YoWA>#bF  
sSiteURL = value; :-b-)*TC;  
} R9Y{kk0M  
JaJyH%+$!  
&([yI>%  
public String getSFilePath() \@j3/!=,n%  
{ XP@&I[J3sI  
return sFilePath; .@Jos^rxgJ  
} 3>^S6h}o  
l{3ZN"`I  
jTok1k  
public void setSFilePath(String value) 71HrpTl1fw  
{
WQY\R!+  
sFilePath = value; z`|E0~{-  
} jx];=IC3tt  
%U&ztvR0C  
StMvz~  
public String getSFileName() mp0!S  
{ HK.Si]:  
return sFileName; 7+J<N@.d  
} zXeBUbVi  
`)1qq @  
Dzw>[   
public void setSFileName(String value) ?D=%k8)Y  
{ d%ncI0f`  
sFileName = value; au7@-_  
} S2 YxA  
']vMOGG  
d|$-l:(J  
public int getNSplitter() +PHuQ  
{ _dn*H-5hO  
return nSplitter; boIFN;Aq"  
} -k@Uo(MB  
ch0x*[N@  
~ZRtNL9  
public void setNSplitter(int nCount) T;B/Wm!x  
{ :J6FI6  
nSplitter = nCount; l65Qk2<YC  
} t?_{  
} LQa1p  
)0 i$Bo  
S >\\n^SbT  
/* a(+u"Kr z  
**Utility.java i8(n(  
*/ IS }U2d,W  
package NetFox; O:[@?l  
VN<baK%]  
hKFB=U  
public class Utility { [{rne2sA  
q&EwD(k  
N
+ei)-  
public Utility() 6)#%36rP  
{ 7o`pNcabtz  
PAy7b7m~B  
.h;X5q1  
} <p8>"~R  
[E/^bM+  
//线程睡眠 F#\+.inO  
public static void sleep(int nSecond)  B*Q  
{ C=PV-Ul+  
try{ iMs(Ywak]  
Thread.sleep(nSecond); +P"u1q*+p  
} e\i}@]  
catch(Exception e) (`K~p Z  
{ U\",!S~<  
e.printStackTrace (); w'!J  
} ju
;Myi}a  
} IHf#P5y_  
<x1H:8A  
//日志 $*d
Y f  
public static void log(String sMsg) !EO 2  
{ m_>~e}2'A  
System.err.println(sMsg); T ^z Mm  
} O6r.q&U  
? 1b*9G%i  
8]0?mV8iOE  
public static void log(int sMsg) Xw9"wAj  
{ @NJJ  
System.err.println(sMsg); ` oXL  
} jh.e&6  
} 1"HSM=p  
sh8(+hg  
T1~,.(#  
/* u=p-]?  
**TestMethod.java kn7Qvk[+  
*/ f%TP>)jag!  
package NetFox; u:O6MO9^  
jj"?#`cW  
U-:_4[
 
public class TestMethod { v@E/?\k"  
|oJ R+  
_<G%  
public TestMethod() |m>n4-5QL  
{ ///xx/weblogic60b2_win.exe "]{"4qV1=  
try{ 8\ WOss)al  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r=pb7=M#LN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]$96#}7N  
SiteFileFetch fileFetch = new SiteFileFetch(bean); lIF*$#`oh*  
fileFetch.start(); Q\<^ih51  
}
J*CfG;Y:  
catch(Exception e){e.printStackTrace ();} Oe%jV,S|V  
I`}<1~ue  
Qz?r4kR  
} 4'-GcH  
VNLggeX'U  
;Cqjg.wkB  
public static void main(String[] args) s|=.L&"   
{ =D~RIt/D  
new TestMethod(); eFeWjB'<7  
} Ayi Uz  
} az ?2  
点击下载更多相关资料