http断点续传简单实现（java)

/* 10$:^  
**SiteFileFetch.java SW=%>XKkh  
*/ kI/%|L%6D  
package NetFox; FO?I}G22  
import java.io.*; <u2iXH5w  
import java.net.*; bE2{^5iG  
Q&?B^[N*Q  
GlaZZ,   
public class SiteFileFetch extends Thread { #oEq)Vq>g|  
(eO_]<wmky  
q4ej7T8  
SiteInfoBean siteInfoBean = null; //文件信息Bean @{x+ln1r  
long[] nStartPos; //开始位置 ;Yn_*M/*  
long[] nEndPos; //结束位置 P!~B07y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 jQ5FvuNOy  
long nFileLength; //文件长度 #5_pE1  
boolean bFirst = true; //是否第一次取文件 7kQ,D,c'  
boolean bStop = false; //停止标志 -|_io,eL;  
File tmpFile; //文件下载的临时信息 Fo&ecWhw  
DataOutputStream output; //输出到文件的输出流 kud2O>>  
&A
~(9IV  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -(|}:J  
public SiteFileFetch(SiteInfoBean bean) throws IOException t2&}  
{ 73(5.'F  
siteInfoBean = bean; %)j^>W5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); dhI+_z   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); mbZg2TTy  
if(tmpFile.exists ()) q@iZo,Yk  
{ =lS@nRH  
bFirst = false; o)Nm5g  
read_nPos(); 5C"A*Fg?;  
} 2T}FX4'  
else *mfPq"/  
{ Aq{7WA
  
nStartPos = new long[bean.getNSplitter()]; a:[m;  
nEndPos = new long[bean.getNSplitter()]; UJGmaE  
} a8r+G]Z  
1Yy*G-7}  
dF0:'y  
Kw,l
n<)2  
} }#9 |au`  
`pYL/[5  
3Tr}t.mt  
public void run() ,:"c"  
{ KPs @v@5M  
//获得文件长度 M@O<b-  
//分割文件 d,%@*v]S  
//实例FileSplitterFetch S3_QOL  
//启动FileSplitterFetch线程 u^&,~n@n7  
//等待子线程返回 4L[-[{2  
try{ v@ OM  
if(bFirst) _c6 zzGtH  
{ Lcy>!3q3~  
nFileLength = getFileSize(); `jH0FJQ  
if(nFileLength == -1) ?&r>`H E  
{ vA,tW,  
System.err.println("File Length is not known!"); "AMsBvzgo  
} s h^&3}  
else if(nFileLength == -2) 5 }F6s  
{ >`+-Yi$(\  
System.err.println("File is not access!"); 407;M%?'A  
} T|lyjX$Q]9  
else zd#/zUPI  
{ t^@4n&Dg  
for(int i=0;i<nStartPos.length;i++) 0Kenyn4?  
{ &\s>PvnquX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "Kt[jV;6  
} 8??%H7~  
for(int i=0;i<nEndPos.length-1;i++) qGc>+!y  
{ MA5BTq<&  
nEndPos = nStartPos[i+1]; ?3Dsz  
} vCtag]H2@  
nEndPos[nEndPos.length-1] = nFileLength; 6d|%8.q1  
} >,%7bq=T!  
} N^&T5cAC  
NuKx{y}P  
oi}\;TG  
//启动子线程 `(?x@Y>.Ht  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .=-K7.X.)  
for(int i=0;i<nStartPos.length;i++) @X*r5hjc  
{ L~xzfO  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bLi>jE.%.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), E>6:59+  
nStartPos,nEndPos,i); e8<[2J)P&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zhFk84  
fileSplitterFetch.start(); BFyVq  
} $2\k| @)s  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YC0FXNV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *FEY"W+bY  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9Fm><,0'u  
nEndPos = " + nFileLength); LXQ-J  
// fileSplitterFetch[nPos.length-1].start(); Gm1vVHAxv  
:ift{XR'  
l<#*[TJ  
//等待子线程结束 a uz2n  
//int count = 0; 1u0NG)*f  
//是否结束while循环 j(maj  
boolean breakWhile = false; u6(>?r-  
&MsBcP[
 
SZQ4e  
while(!bStop) )51
H\o  
{ 8y, ]>n  
write_nPos(); xkzC+ _A  
Utility.sleep(500); bbO1`b-  
breakWhile = true; N/fH%AtM  
t'0dyQ%u  
`[5QouPV  
for(int i=0;i<nStartPos.length;i++) 7T3ub3\  
{ +#!! 'XP  
if(!fileSplitterFetch.bDownOver) 5=--+8[ bV  
{ lj!f\C}d  
breakWhile = false; H|iY<7@  
break; g+98G8R  
} ?5L.]Isa5  
} [1*3 kt*h  
if(breakWhile) s$ 2@|;  
break; Qm X(s  
N yK7TKui  
p7;/| ]o3  
//count++; Ih.6"ISK}  
//if(count>4) 8Dq;QH}  
// siteStop(); ,??%["R  
} C%csQ m  
l;dZJ_Ut$  
Ysk,9MR(F  
System.err.println("文件下载结束！"); MMfcY 3#%  
} C  +%&!Q  
catch(Exception e){e.printStackTrace ();} zU'\r~c  
} &&;ol}W  
]'F{uDm[  
5Go&+|cvJ  
//获得文件长度 }bVWV0Aeim  
public long getFileSize() ''f07R  
{ L@|W&N;%a  
int nFileLength = -1; XKU+'Tz  
try{ }'KVi=qnHb  
URL url = new URL(siteInfoBean.getSSiteURL()); VBIY[2zf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x^|J-
  
httpConnection.setRequestProperty("User-Agent","NetFox"); e:Zc-  
0pS|t/h0  
0NB6S&lI^k  
int responseCode=httpConnection.getResponseCode(); lr[a~ca\  
if(responseCode>=400) ~_TmS9  
{ xPY/J#X$  
processErrorCode(responseCode); 38
%xB<Y  
return -2; //-2 represent access is error E Cx_ [|3{  
} Dm j^aFB0|  
F-)lRGw  
zOpl#%"  
String sHeader; bg'B^E3  
Fs_umy#  
wR?M2*ri   
for(int i=1;;i++) -k p~pe*T  
{ ,))UQ7N  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [UVxtMJ  
//Utility.log(in.readLine()); $C UmRi{T  
sHeader=httpConnection.getHeaderFieldKey(i); |yi3y `f  
if(sHeader!=null) Ok+zUA[Wu  
{ 9K@>{69WQ  
if(sHeader.equals("Content-Length")) FBM 73D@`  
{ N;A#3Ter  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); U/2g N H  
break; ]Ph~-O  
} eiJO;%fl>l  
} -}m#uUqI  
else 4'W|'4'b  
break; &t+  
} \guZc}V]:\  
} .[hQ#3)W  
catch(IOException e){e.printStackTrace ();} %6}S'yL  
catch(Exception e){e.printStackTrace ();} j[XA"DZR<  
8z^?PZ/  
R$&|*0  
Utility.log(nFileLength); 0KyujU?sF  
A/N$  
qwu++9BM  
return nFileLength; ~ySmN}3~'  
} r3l}I6  
bh&,*Y6=  
@^y/V@lDm  
//保存下载信息（文件指针位置） ~y}M GUEC  
private void write_nPos() K h9$  
{ :z^ps0  
try{ :".:Wd  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ObIi$uJX  
output.writeInt(nStartPos.length); S<f&?\wK=v  
for(int i=0;i<nStartPos.length;i++) w~EXO;L2  
{ z= -u89]  
// output.writeLong(nPos); mf'N4y%  
output.writeLong(fileSplitterFetch.nStartPos); oh`I$  
output.writeLong(fileSplitterFetch.nEndPos); `e0U-W]kF  
} sB_o HUMH6  
output.close(); !ZbNW4rIP  
} n37C"qJ/i  
catch(IOException e){e.printStackTrace ();} ]<q{0.  
catch(Exception e){e.printStackTrace ();} K6kPNi  
} kx'ncxN~  
:b;2
iBVB  
YNbs*i&  
//读取保存的下载信息（文件指针位置） zh'TR$+\hO  
private void read_nPos()   /I  
{ =y8HOT}8  
try{ EH"iK2n\
9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); pvTV*  
int nCount = input.readInt(); #lQbMuR  
nStartPos = new long[nCount];
}$V]00 X  
nEndPos = new long[nCount]; !%NxSJ  
for(int i=0;i<nStartPos.length;i++) j-ugsV`2=*  
{ -9/YS  
nStartPos = input.readLong(); 6rL'hB!!]*  
nEndPos = input.readLong(); j4le../N  
} Qp<?[C}'W  
input.close(); TH/!z,(>  
} yw5MlZ4P=  
catch(IOException e){e.printStackTrace ();} 4hztYOhJ{  
catch(Exception e){e.printStackTrace ();} Hjli)*ev  
} M|FwYF^  
jK\2y|&&c  
K;G1cFFyG  
private void processErrorCode(int nErrorCode) \~Zj](#  
{ ;C-5R U V  
System.err.println("Error Code : " + nErrorCode); m?xzx^xs/  
} !,Wd$UK  
BnqAv xX  
=2bW"gs I  
//停止文件下载 JGSeu
=)  
public void siteStop() }nYm^Yh  
{ SY["(vP%#  
bStop = true; e%N\Pshgv  
for(int i=0;i<nStartPos.length;i++) Z?[;Japg  
fileSplitterFetch.splitterStop(); "j3Yu4_ks  
|Wj)kr !|  
SxC$EQgL  
} $I-$X?  
} N7%Jy?-+  
//负责部分文件的抓取 bXc7$5(!VB  
**FileSplitterFetch.java 7i~::Z <  
*/ GY<Y,  
package NetFox; [+gX6  
P$2J`b[H$  
2Y&z}4'j  
import java.io.*; 8 +xLi4Pw  
import java.net.*; WE4
:Jy  
iBxCk^  
B+ GPTQSTb  
public class FileSplitterFetch extends Thread { WW@/q`h  
jfl7L"2  
AZorzQ]s
 
String sURL; //File URL Y:G6Nd VFM  
long nStartPos; //File Snippet Start Position B8Jev\_  
long nEndPos; //File Snippet End Position 0gHJ%m9s  
int nThreadID; //Thread's ID w@.E}%bwq  
boolean bDownOver = false; //Downing is over A2Rr*e  
boolean bStop = false; //Stop identical I'BoP  
FileAccessI fileAccessI = null; //File Access interface 2j H`  
8;p6~&).C~  
uwQ{y>SG  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException J7emoD[  
{ O~9 %!LAu  
this.sURL = sURL; %fh ,e5(LT  
this.nStartPos = nStart; =9y'6|>l  
this.nEndPos = nEnd; ;%]
Q%7  
nThreadID = id; \Yz>=rY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1]fqt[*)  
} :cG_aOkid  
sqei(OXy  
i5|A\Wv"  
public void run() ~m[^|w  
{ @pYAqX2  
while(nStartPos < nEndPos && !bStop) )#T(2A  
{ :74^?  
(E&}SI~  
2y#4rl1Utx  
try{ C#p$YQf  
URL url = new URL(sURL); 9Q^>.^~^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ne@Iv)g?  
httpConnection.setRequestProperty("User-Agent","NetFox"); v/8K?$"q  
String sProperty = "bytes="+nStartPos+"-"; tn6\0_5n  
httpConnection.setRequestProperty("RANGE",sProperty); Jm\'
=#U#  
Utility.log(sProperty); 0^]E-Zf  
 ,L\OhT  
7&:gvhw  
InputStream input = httpConnection.getInputStream(); JE9|;A  
//logResponseHead(httpConnection); vC$[Zm  
QZ"Lh  
s8{3~Hv  
byte[] b = new byte[1024]; +G?4Wc1  
int nRead; -#Yg B5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9O?.0L  
{ 8Y sn8  
nStartPos += fileAccessI.write(b,0,nRead); Vg\EAs>f  
//if(nThreadID == 1) D^04b<O<x  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f 7y1V(t  
} 0D/j2cT("k  
k:Uyez  
;6L<Syl5  
Utility.log("Thread " + nThreadID + " is over!"); 0DIaXdOdW+  
bDownOver = true; n+rAbn5o$  
//nPos = fileAccessI.write (b,0,nRead); xI<Dc*G  
} hBLJKSv  
catch(Exception e){e.printStackTrace ();} IJs*zzR  
} g/mVd;#o  
} q3VE\&*^F  
OlRBvfoh8  
k
^p|H:  
//打印回应的头信息 MH'S,^J  
public void logResponseHead(HttpURLConnection con) Mm:6+  
{ .O3i"X]  
for(int i=1;;i++) pYI`5B4  
{ g>_6O[;t%  
String header=con.getHeaderFieldKey(i); (pH13qU5  
if(header!=null) >72j,0=e  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); X{9D fgW  
Utility.log(header+" : "+con.getHeaderField(header)); PX(.bP2^Lq  
else j S')!Wcu  
break; =KmjCz:  
} -G(z!ed  
} +su>0'a  
giyKEnP  
KU"?ZI  
public void splitterStop() y!1%Kqx1,n  
{ ]V<[W,*(5  
bStop = true; lHV bn7  
} pTST\0?  
{Rc/Ten  
&%>l9~F'~  
} s59
v* /  
z=N'evx~  
AVOzx00U  
/* {e<J}-/?  
**FileAccess.java (%oZgvM  
*//文件访问(定位，写) ,`^B!U3m   
package NetFox; 8,a&i:C  
import java.io.*; 9<.Fw
V>  
7F>5<Gv:-  
3:PBVt=  
public class FileAccessI implements Serializable{ iJZqAfG{m?  
;jfjRcU  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0X~   
RandomAccessFile oSavedFile; T3@wNAAU  
long nPos; $`i$/FE  
b~Y
$!fc  
g*N~r['dZ  
public FileAccessI() throws IOException R KFz6t  
{ % rRYT8  
this("",0); m_W\jz??k  
} ;? '`XB!  
%q;3bfq@N  
8
%_XJyg  
public FileAccessI(String sName,long nPos) throws IOException [k
t!\-  
{ 9Y&n$svB  
oSavedFile = new RandomAccessFile(sName,"rw"); 
fv5'Bl  
this.nPos = nPos; M+gQN}BAr  
oSavedFile.seek(nPos); ;'`T  
} [`Ol&R4k  
d8C?m*3J  
!?DPI)  
public synchronized int write(byte[] b,int nStart,int nLen) 4+:Q"  
{ );kO27dg  
int n = -1; aG%KiJ7KEN  
try{ qy`@\)S/5  
oSavedFile.write(b,nStart,nLen); Ih;6(5z  
n = nLen; `ihlKFX  
} u&I?LZ-=,  
catch(IOException e) TKx.`Cf m  
{ 7ib~04
  
e.printStackTrace (); _SY<(2s]B  
} Gx|$A+U  
jF<Y,(C\  
rqxoqcZ  
return n; mEa\0oPGB  
} k_r12Bu  
:2^%^3+V  
KqP!={>"  
} SuB;Nb7r`  
JX7_/P  
|qH-^b.F  
/* Sqed*  
**SiteInfoBean.java Lp5LRw  
*/ >to NGGU=~  
package NetFox; lE78Yl]  
UA!-YTh  
AY5%<CWj8  
public class SiteInfoBean { .5p"o-:D  
G!RbM.6  
mQ;b'0&  
private String sSiteURL; //Site's URL M n`gd#  
private String sFilePath; //Saved File's Path rZLTai}`>  
private String sFileName; //Saved File's Name |_&vW
\  
private int nSplitter; //Count of Splited Downloading File v,bes[Ik  
[M65T@v  
^Y
8?iC<+  
public SiteInfoBean() b6RuYwHWV0  
{//nSplitter的缺省值为5 O]DZb+O"  
//default value of nSplitter is 5 Zgkk%3'^'  
this("","","",5); M/x49qO#  
} ( MWh|kp  
eGHxiC  
^ b{0|:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J(ZYoJ  
{ ]OL O~2
j  
sSiteURL= sURL; 7<*sP%6bD  
sFilePath = sPath; 0UB)FK,9  
sFileName = sName; %"r3{Hs  
this.nSplitter = nSpiltter;
(TM1(<j  
7;:R\d6iL  
&|'1.^f@;E  
} #K.OJJaG  
12U1DEd>-  
0k>bsn/j  
public String getSSiteURL() QFY1@2EC  
{ \L>3E#R-Q  
return sSiteURL; RZ#b)
l  
} 5<wIJ5t  

1//d68*"  
F.i*'x0u  
public void setSSiteURL(String value) i+( k  
{ }dQW-U  
sSiteURL = value; L:nZ_O;  
} pUutI|mt/  
g VX  
bCHJLtDQ  
public String getSFilePath() m/Ou$  
{ cK%Sty'8+  
return sFilePath; .|^L\L(!  
} 1v)ur\>R  
[`Se
h$  
M>nplHq   
public void setSFilePath(String value) tGDsZ;3Yr  
{ LG0+A}E=C  
sFilePath = value; a'u:1C^\  
} C ?JcCD2  
XZde}zUWn  
piIj t  
public String getSFileName() VRQ'sn@  
{ [0<N[KZ)  
return sFileName; T}d%XMXq  
} P&@ 2DI3m  
i}"Eu< P  
1O3"W;SR<:  
public void setSFileName(String value) _;/onM  
{ LI1OocY.]  
sFileName = value; i eQQ{iGJH  
} 4WU%K`jnXb  
 b)/,  
aqJ>l}{  
public int getNSplitter()
mX66}s}#  
{ 6..G/,T
B  
return nSplitter; :ZX#w`Y  
} D]X&Va  
1(t{)Z<  
 -i*{8t  
public void setNSplitter(int nCount) RG[b+Qjn  
{ qp$Td<'Y  
nSplitter = nCount; 8 :B(}Y4K  
} *{[jO&
&J  
} Hj\>&vMf  
KnK8\p88\  
7.U CX"  
/* MG6taOO!  
**Utility.java 4+46z|  
*/ ZyAm:yO  
package NetFox; jyB^a;-  
1 ? be  
o+Cd\D69S  
public class Utility { "g}mxPe  
x[L/d"Wf  
>F7v'-*{  
public Utility() vU|=" #  
{ |hGi8  
kD1[6cJ!=.  
+9Vp<(  
} )2
vkaR  
X|]&K  
//线程睡眠 {Aq2}sRl{  
public static void sleep(int nSecond) ))Q3;mI"  
{ K`%{(^}.  
try{ C.su<B?  
Thread.sleep(nSecond); ,Hq*zc
c  
} f-]5Z
hM'  
catch(Exception e) ~d5f]6#`  
{ q8 jI y@  
e.printStackTrace (); Igb@aGA  
} hHXTSk2  
} (.D|%P  
BuwJR Ql.  
//日志 3hUU$|^4gm  
public static void log(String sMsg) ]H[%PQ r`Z  
{ :x*#RnRr.  
System.err.println(sMsg); U42B(ow  
} ? }t[  
{Ee[rAVGp  
lJ y\Ky(*  
public static void log(int sMsg) >2kjd  
{ iH&BhbRu_  
System.err.println(sMsg); ?-.Qv1hs6p  
} bSbUf%LKt  
} a[).'$S}'  
(c3%rM m]  
>U4hsr05  
/* w&U>w@H^  
**TestMethod.java 4<c#3]  
*/ #@qd.,]2  
package NetFox; ~m0l_:SF  
pXL@&]U
+  
b Ag>;e(  
public class TestMethod { j=>:{`*c  
/U1&#"P  
w]-,X`  
public TestMethod() H<YhO&D*u  
{ ///xx/weblogic60b2_win.exe Ic!8$NhRS  
try{ L"Vi:zdp  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "V7 SB   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); s01W_P.@R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {Kdr-aC  
fileFetch.start(); vBRW5@  
} s"jNS1B  
catch(Exception e){e.printStackTrace ();} T][r'jWQ  
cx_.+R  
aNcuT,=(?8  
} estDW1i)  
Qx{[#[Da  
(=de#wh2]  
public static void main(String[] args) 6<%W8m\  
{ e 9p+  
new TestMethod(); t
93iU?Z  
}
wfE%` 1  
} Z{#;my*X|  
点击下载更多相关资料