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http断点续传简单实现(java)

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/* 7\ZSXQy1W  
**SiteFileFetch.java =''b`T$  
*/ I?Z"YR+MQ  
package NetFox; ,el[A`b  
import java.io.*; W$`#X  
import java.net.*; U0iV E+)Bt  
jw 5 U-zi  
HL dHyK/S  
public class SiteFileFetch extends Thread { nJ/}b/A{  
c-!3wvt)  
B(5>H2  
SiteInfoBean siteInfoBean = null; //文件信息Bean ^SW9J^9  
long[] nStartPos; //开始位置 K4+|K:e  
long[] nEndPos; //结束位置 71ab&V il  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +@H{H2J4  
long nFileLength; //文件长度 M{jq6c  
boolean bFirst = true; //是否第一次取文件 `%EcQ}Nr  
boolean bStop = false; //停止标志 GV28&!4sS  
File tmpFile; //文件下载的临时信息 p )]x,F  
DataOutputStream output; //输出到文件的输出流 & JJ*?Dl  
_ n1:v~  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) shP}T[<  
public SiteFileFetch(SiteInfoBean bean) throws IOException F2ISg'  
{ z#rp8-HUDS  
siteInfoBean = bean; OVc)PMp  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2-W y@\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >oaL-01i  
if(tmpFile.exists ()) o^MoU2c  
{ 3 TTQf f  
bFirst = false; zSu,S4m_;  
read_nPos(); wXKt)3dmu  
} TJ_6:;4,|_  
else Zb|a\z8?  
{ {E7STLQ_%  
nStartPos = new long[bean.getNSplitter()];  qmenj  
nEndPos = new long[bean.getNSplitter()]; LR\8M(rtvH  
} pd & HC  
R@/"B?`(f  
2JcP4!RD  
3 `mtc@*  
} >,I'S2_Zl  
!IB}&m  
9sd}Z,l  
public void run() wO`G_!W9  
{ rk@qcQR  
//获得文件长度 8xG"hJR  
//分割文件 [Fv,`*/sm  
//实例FileSplitterFetch 8.7q -<Q  
//启动FileSplitterFetch线程 !^v~hD$_q  
//等待子线程返回 z|Yt|W  
try{ @A(jo32  
if(bFirst) C5$?Y8B3  
{ vy2"B ch  
nFileLength = getFileSize(); fakad#O  
if(nFileLength == -1) t5u#[*  
{ wu &lG!#  
System.err.println("File Length is not known!"); bNiJ"k<pN  
} r4fg!]J ;  
else if(nFileLength == -2) )0"T?Ivp]  
{ U@{>+G[  
System.err.println("File is not access!"); o^//|]H3Y  
} F- u"zox  
else  -T-yt2h(  
{ Z glU{sU  
for(int i=0;i<nStartPos.length;i++) n:b,zssP  
{ :i@ $s/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); t~nW&]E  
} %+;l|Z{Uf  
for(int i=0;i<nEndPos.length-1;i++) 5,V*aP  
{ "r3h+(5  
nEndPos = nStartPos[i+1]; 3bjCa\ "  
} 2V u?Y  
nEndPos[nEndPos.length-1] = nFileLength; 9 `q(_\x  
} m\bmBK"I  
}  H{Lt,#  
f5l\3oL  
[p}~M-$V8Y  
//启动子线程 e"XolM0IM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Wm5[+z|2?9  
for(int i=0;i<nStartPos.length;i++) </?ef&  
{ *M0O&"~j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m({ q<&]Qp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), q;IuV&B  
nStartPos,nEndPos,i); CdPQhv)m  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D%c^j9' 1  
fileSplitterFetch.start(); UQ7La 7"  
} n<<arO"cv  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?~#[ cx  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z7[S698  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", J^%E$ s  
nEndPos = " + nFileLength); ^Jdg%U?  
// fileSplitterFetch[nPos.length-1].start(); ,j\uvi(Y  
v0tFU!Q%  
dLwP7#r  
//等待子线程结束 8*&73cp  
//int count = 0; )  LTV+?  
//是否结束while循环 l @@pXg3  
boolean breakWhile = false; ^P/OHuDL  
 w}t}Sh  
m qUDve(  
while(!bStop) Fi\) ka\u  
{ |ITb1O`_P  
write_nPos(); @~N"MsF3  
Utility.sleep(500); gTB|IcOs  
breakWhile = true; ;X0uA?  
;:ZD<'+N  
qQO*:_ezzk  
for(int i=0;i<nStartPos.length;i++) \F\7*=xk  
{ D!Nc&|X^  
if(!fileSplitterFetch.bDownOver) .h4Z\R`  
{ v)nv"o[  
breakWhile = false; {#`wW`U^  
break; LmJ _$?o  
} #UI`+2w  
} Yl$ @/xAa  
if(breakWhile) l[m*csDk"  
break; j \d)#+;  
Zy:q)'D=  
K V?+9qa,  
//count++; @Gw]cm  
//if(count>4) O&~ @ior  
// siteStop(); nmE H/a  
} QQS "K g  
yv>uzb`N  
f;l}Z|dok6  
System.err.println("文件下载结束!"); wN/v-^2  
} DAORfFG74  
catch(Exception e){e.printStackTrace ();} u(? U[pe[  
} A=e1uBGA  
k]RQ 7e  
7v0VZ(UR  
//获得文件长度 I69Z'}+qz  
public long getFileSize() XtBEVqrhi  
{ R"CF xo  
int nFileLength = -1; `zl,|}u)  
try{ g}a+%Obb  
URL url = new URL(siteInfoBean.getSSiteURL()); OPqhdqo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]iFW>N*a  
httpConnection.setRequestProperty("User-Agent","NetFox"); D@[#7:rHL  
-HuIz6  
HJpx,NU'  
int responseCode=httpConnection.getResponseCode(); (dO0`wfM  
if(responseCode>=400) V|HO*HiB3  
{ (I>SqM Y  
processErrorCode(responseCode); |o(te  
return -2; //-2 represent access is error f.oY:3h:  
} xUa9>=JU{  
UCFFF%  
';D>Z ?l  
String sHeader; aYHs35  
}S13]Kk?=  
1Ak0A6E  
for(int i=1;;i++) een62-`  
{ ^( 7l!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); rd[mC[ r  
//Utility.log(in.readLine()); ];g ~)z  
sHeader=httpConnection.getHeaderFieldKey(i); {CVZ7tU7]  
if(sHeader!=null) C$LRX7Z`o  
{ X9^q-3&60  
if(sHeader.equals("Content-Length")) bmKvvq  
{ k][{4~z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r8czDc),b  
break; ybv< 1  
} n%~r^ C_  
} $ >].;y?$  
else QAZs1;lU  
break; ]2iIk=r$  
} 3!#FG0Z   
} 55y{9.n*  
catch(IOException e){e.printStackTrace ();} -JFW ,8=8  
catch(Exception e){e.printStackTrace ();} q9InO]s&~=  
<&)zT#"  
Pmr'W\aIR  
Utility.log(nFileLength); '9<8<d7?  
r4K%dx-t  
ATmyoN2@>  
return nFileLength; ,5 3`t  
} j0 Os]a  
]lE5^<<  
aSHN*tP%y  
//保存下载信息(文件指针位置) uz=9L<$  
private void write_nPos() B/hQvA;(  
{ ?A*<Z%}1?  
try{ A4;~+L:M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )2Y]A^Y   
output.writeInt(nStartPos.length); @KZW*-"  
for(int i=0;i<nStartPos.length;i++) EF=5[$ u  
{ < mFU T  
// output.writeLong(nPos); 7nW <kA  
output.writeLong(fileSplitterFetch.nStartPos); ^d(gC%+!u  
output.writeLong(fileSplitterFetch.nEndPos); .O+,1&D5  
} &/otoAr(  
output.close(); _ph1( !H$  
} nU#K=e =W  
catch(IOException e){e.printStackTrace ();} Gs04)KJm<  
catch(Exception e){e.printStackTrace ();} $h=v ;1"  
} vJx( lU`Y  
(gcy3BX;  
|&bucG=  
//读取保存的下载信息(文件指针位置) WBzPSnS2  
private void read_nPos() l%yQ{loTh  
{ jrttWT  
try{ +#X+QG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9]/:B8k  
int nCount = input.readInt(); >29c[O"[  
nStartPos = new long[nCount]; F^}d>2W(  
nEndPos = new long[nCount]; L}g#h+GP[  
for(int i=0;i<nStartPos.length;i++) wW<u)|>ye  
{ uX1{K%^<TW  
nStartPos = input.readLong(); ,eqRI>,\  
nEndPos = input.readLong(); X?`mYoe  
} M%SNq|Lo  
input.close(); %Z*)<[cIE0  
} KXWz(L!1  
catch(IOException e){e.printStackTrace ();} v`6vc)>8  
catch(Exception e){e.printStackTrace ();} !l6ht {  
} Un5 AStG  
0+w(cf~6  
yaHkWkl =  
private void processErrorCode(int nErrorCode) '?X?'_3  
{ >+:cTQ|q  
System.err.println("Error Code : " + nErrorCode); ##1/{9ywy  
} MdTu722  
xz +;1JAL3  
X@)'E9g5:  
//停止文件下载 ~1S,[5u|s  
public void siteStop() F hyY+{%  
{ mFd|JbW  
bStop = true; 5,Co(K  
for(int i=0;i<nStartPos.length;i++) jz\>VYi(7  
fileSplitterFetch.splitterStop(); 6hXh;-U  
6_g6e2F  
{e., $'#  
} `sd H q  
} Vk76cV D  
//负责部分文件的抓取 N7;kWQH  
**FileSplitterFetch.java @TzUc E  
*/ zMO xJ   
package NetFox; ]2[\E~^KU  
B.gEV*@  
;L%\[H>G  
import java.io.*; ;9Wimf]G,E  
import java.net.*; cBCC/n  
%8P6l D  
@?0))@kPc3  
public class FileSplitterFetch extends Thread { RE]*fRe7#  
"|PX5  
^Q!A4 qOQ  
String sURL; //File URL 1ZvXRJ)%  
long nStartPos; //File Snippet Start Position h6tYy_(G  
long nEndPos; //File Snippet End Position EKmn@S-&P  
int nThreadID; //Thread's ID `2q]ju  
boolean bDownOver = false; //Downing is over Jl$ X3wE  
boolean bStop = false; //Stop identical u|Ng>lU  
FileAccessI fileAccessI = null; //File Access interface }|znQ3A2\l  
1XHE:0!dQ  
i3$pqNe  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N#X* 0i"  
{ 0P;LH3sx  
this.sURL = sURL; $vn x)#r3  
this.nStartPos = nStart; J@ 8OU  
this.nEndPos = nEnd; %e+*&Z',  
nThreadID = id; ~!/agLwY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Xl>ZnI];  
} q$}gQ9'z'  
X0LC:0+  
3u,B<  
public void run() C!Fi &~  
{ iD>H{1 h  
while(nStartPos < nEndPos && !bStop) ._&SS,I5VZ  
{ z|$9%uz"  
y%<CkgZS  
Ejyo oO45  
try{ ]Z*B17//  
URL url = new URL(sURL); >g{b'Xx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x,GLGGi}_x  
httpConnection.setRequestProperty("User-Agent","NetFox"); gYmO4/c,  
String sProperty = "bytes="+nStartPos+"-"; ( F4c0  
httpConnection.setRequestProperty("RANGE",sProperty); $A T kCO  
Utility.log(sProperty); gy"<[N .?c  
Cli:;yi&n  
| vxmgX)  
InputStream input = httpConnection.getInputStream(); Lw<.QMN%f  
//logResponseHead(httpConnection); }!m}?  
J58S8:c  
/.sho\a  
byte[] b = new byte[1024]; KD- -w(4  
int nRead; 4"\%/kG  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ZM [Z9/S8  
{ WDt6{5T  
nStartPos += fileAccessI.write(b,0,nRead); LbR'nG{J  
//if(nThreadID == 1) x]t$Zb/Uxa  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F;BCSoO4  
} =RQI5 nHdw  
mo&9=TaG  
d *#.(C9^  
Utility.log("Thread " + nThreadID + " is over!"); \[ 4y  
bDownOver = true; %pf9Yd0t  
//nPos = fileAccessI.write (b,0,nRead); j@{dsS: 6  
} ! w;/J^  
catch(Exception e){e.printStackTrace ();} @R(Op|9  
} (ki= s+W-  
} wNmC1HOh  
Ns5P,[pBOZ  
Ep3I*bQ Y  
//打印回应的头信息 f85~[3 J  
public void logResponseHead(HttpURLConnection con) E5Sn mxd  
{ Z_[L5B]Gwd  
for(int i=1;;i++) {xh5s<uOj  
{ QXgfjo  
String header=con.getHeaderFieldKey(i); Zx7aae_{  
if(header!=null) @ 'U`a4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Sf@xP.d  
Utility.log(header+" : "+con.getHeaderField(header)); zMd><UQP{  
else SIc~cZ!Yu  
break; :39arq  
}  2IGU{&s  
} ]bYmM@  
XWq"_$&LF  
jB l$r{L  
public void splitterStop() N7YCg  
{ O2"V'(  
bStop = true; ,LDL%<7t  
} Ge^,hAM'  
W>: MK-_ J  
6~x a^3G:  
} aIh} j,  
a2/Mf   
[jrfh>v  
/* M0OIcMTv  
**FileAccess.java <FI*A+I4\  
*//文件访问(定位,写) NytodVZ'3  
package NetFox; m9+?>/R  
import java.io.*; 2 )3oX  
-  eIo  
)d2:r 07a  
public class FileAccessI implements Serializable{ #^R@EZ  
23 #JmR  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]'w5s dP  
RandomAccessFile oSavedFile; @u: `  
long nPos; 0WYu5|  
G?61P[j7  
5UG9&:zu'V  
public FileAccessI() throws IOException ,KU%"{6  
{ fNfa.0 s  
this("",0); !hHX8TD^J  
} axq~56"7E  
\fuz`fK:  
Z:es7<#y  
public FileAccessI(String sName,long nPos) throws IOException [-\U)>MY(p  
{ q/d?c Lgl  
oSavedFile = new RandomAccessFile(sName,"rw"); V>GJO(9  
this.nPos = nPos; lyyf&?2  
oSavedFile.seek(nPos); J9DI(`  
} n&zEYCSI  
WWH<s%C  
`%"x'B`mM  
public synchronized int write(byte[] b,int nStart,int nLen) tE <?L  
{ kqxq'Aq)d  
int n = -1;  7Z<GlNv  
try{ -Fu,oEj{*  
oSavedFile.write(b,nStart,nLen); CDsl)  
n = nLen; I,HtW),  
} FQ`1c[M@  
catch(IOException e) vqO#Z  
{ 2oRwDg&7|  
e.printStackTrace (); PAtv#)h  
} z8]@Gh+ (  
+"bi]^\z  
(E&M[hH+  
return n; \Q1&w2mw  
} '}B"071)<  
?%Tx% dB  
o0S 8ki  
} (2M00J-o  
v+`'%E  
)pT5"{  
/* 3S2Alx!6  
**SiteInfoBean.java b4bd^nrqV  
*/ N-knhA  
package NetFox; r jxkgd  
NH}o`x/  
_z{9V7n4  
public class SiteInfoBean { (xVx|:R[<H  
6NhGTLI  
g1"Z pD  
private String sSiteURL; //Site's URL ;in-)`UC!  
private String sFilePath; //Saved File's Path D15-pz|Q  
private String sFileName; //Saved File's Name G/ ~gF7  
private int nSplitter; //Count of Splited Downloading File Bp5ra9*5+~  
;v2eAe@7  
?eX/vqk  
public SiteInfoBean() q*` m%3{  
{//nSplitter的缺省值为5 LP|YW*i=IQ  
//default value of nSplitter is 5 SJMbYjn0J  
this("","","",5); C58o="L3S  
} -WF((s;<#  
S7nx4c2xK~  
Pmd[2/][  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) HF_8661g  
{ Q~svtN  
sSiteURL= sURL; FdzdoMY  
sFilePath = sPath; &Mudu/KTr  
sFileName = sName; Og1vD5a  
this.nSplitter = nSpiltter; RJerx:]  
0zSz[;A  
>c<xy>N  
} K[OOI~"C  
R2-F@_  
3 e1-w$z&S  
public String getSSiteURL() Uuu2wz3O0  
{ :H m'o}  
return sSiteURL; Xo~q}(ze^  
} 0+@:f^3]!  
QkD ~  
0!0e$!8l  
public void setSSiteURL(String value) /(hTk&  
{ ,f:K)^yD  
sSiteURL = value; w(S~}'Sg*P  
} _u$DcA8B  
?#(LH\$l_  
]k7%p>c=B  
public String getSFilePath() 37a1O>A  
{ z+6PVQ  
return sFilePath; A-=hvJ5T  
} rM A%By^L-  
C`kqsK   
tJ>>cFx  
public void setSFilePath(String value) _",(!(  
{ Q*ELMib  
sFilePath = value; w->Y92q]  
} , ftJw  
s=jYQ5nv  
$9Bzq_!  
public String getSFileName() i({\fb|0  
{ !'F1Ht  
return sFileName; YF-E1`+?<  
} sfn^R+x4,9  
O(8CrKYY  
u_9c>  
public void setSFileName(String value) ui#nN   
{ .Hqq!&  
sFileName = value; 5= &2=  
} Y8v[kuo7  
= wDXlAQ  
r.zgLZ}3&V  
public int getNSplitter() }Cw,m0KV/  
{ f*Q9u>1p  
return nSplitter; i^.eX VV/  
} `Tyd1!~  
M3@qhEf?vk  
IA.7If&k  
public void setNSplitter(int nCount) [j'!+)>_  
{ +z?gf*G_W'  
nSplitter = nCount; /Z^a, %1  
} 87l*Y|osP  
} )/)u.$pi  
W#P\hx  
[ R+M .5  
/* L f"!:]  
**Utility.java [y'blCb  
*/ N'EZJ oH  
package NetFox; U-1UWq  
!fn%Q'S  
H<i!C|AF  
public class Utility { !10/M  
rmkBp_i{|  
K\U`gTGc  
public Utility() IMqe(  
{ [iq^'E  
E#rQJ  
vMou`[\WlJ  
} ,s 3|  
6&SNFOX{@  
//线程睡眠 zytN leyc  
public static void sleep(int nSecond) \z!lw  
{ `IwZVz  
try{ ~//9Nz~;3  
Thread.sleep(nSecond); l%GArH`  
} N^[ F+y  
catch(Exception e) > VIFQ\  
{ /Ls|'2J<$  
e.printStackTrace (); k $^/$N  
} TU~y;:OJ  
} #`|Nm3b  
G2I%^.s  
//日志 @~ke=w6&pe  
public static void log(String sMsg) ~v2(sRJ  
{ A)n_ST0  
System.err.println(sMsg); 3<$Ek3X  
} b; C}=gg  
vPYHM2  
F6yFKNK!n  
public static void log(int sMsg) iU 6,B  
{ 8TB|Y  
System.err.println(sMsg); \a;xJzc9  
} J  Y8Rk=  
} Q<V1`e  
)JTQZ,f3]  
RDDA^U7y#  
/* >fP;H}S6  
**TestMethod.java m\jjj^f a  
*/ [nVBnB  
package NetFox; w"[T  
lJFy(^KQG,  
i,;eW&  
public class TestMethod { eJ45:]_%I@  
(,o@/ -o  
!^F_7u@Q  
public TestMethod() .gC.T`/m  
{ ///xx/weblogic60b2_win.exe 3^ UoK  
try{ v?]a tb/h`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1\@PrO35J  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fTR6]i;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?'f  
fileFetch.start(); 2C:u)}R7D  
} !YGHJwW:  
catch(Exception e){e.printStackTrace ();} N5zWeFq@6  
D['J4B  
)s:kQ~+  
} |0}Xb|+  
T\p>wiY2|F  
`!N}u  
public static void main(String[] args) ? Pi|`W   
{ 5%9Uh'y#  
new TestMethod(); Go c*ugR  
} U { 0~&  
} a"YVr'|  
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