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http断点续传简单实现(java)

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/* *'exvY~  
**SiteFileFetch.java =WDf [?ED  
*/ q &jW{  
package NetFox; {' r(P&  
import java.io.*; JmN;v|wF:c  
import java.net.*; eTrGFe!8w  
J>Zd75;U  
Y71b Lg  
public class SiteFileFetch extends Thread { *+@/:$|U  
g3x192f  
06Uxd\E~  
SiteInfoBean siteInfoBean = null; //文件信息Bean )]qFI"B7  
long[] nStartPos; //开始位置 D-,sF8{ i  
long[] nEndPos; //结束位置 \19XDqf8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 gVq{g,yi  
long nFileLength; //文件长度 |ZRl.C/e  
boolean bFirst = true; //是否第一次取文件 &V$'{  
boolean bStop = false; //停止标志 =1+I<Ljk  
File tmpFile; //文件下载的临时信息 k5}i^^.  
DataOutputStream output; //输出到文件的输出流 1/1P;8F@G  
-,4_ &V  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) *r9I 1W  
public SiteFileFetch(SiteInfoBean bean) throws IOException \nxt\KD  
{ <T0-m?D_$  
siteInfoBean = bean; R^8Opf_UN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); < W&~tVv  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2 ] 4R`[#  
if(tmpFile.exists ()) Po^2+s(fY  
{ n\cP17dr  
bFirst = false; 88G[XkL$2  
read_nPos(); OWq~BZ{  
} `yC R.3+  
else eJy@N  
{ IOmIkx&`GP  
nStartPos = new long[bean.getNSplitter()]; pl"|NZz 7;  
nEndPos = new long[bean.getNSplitter()]; W/?D}#e<4  
} L<Lu;KnY6  
rxDule3m  
0U$6TDtmE  
X.UIFcK^  
} (Yw5X_|  
xX"?3%y>  
1p8E!c{}j  
public void run() %FF  S&vd  
{ 5#2vSq!H  
//获得文件长度 1/#N{rZ  
//分割文件 eY&UFe  
//实例FileSplitterFetch ~:+g+Mf~[  
//启动FileSplitterFetch线程 _Yh4[TT~/  
//等待子线程返回 /6S/a*`<X  
try{ Q&F@[k  
if(bFirst) h+$_:](PC  
{ cAktSoF  
nFileLength = getFileSize(); z1V0WDVm  
if(nFileLength == -1) y*7ht{B  
{ :fj}J)9'xW  
System.err.println("File Length is not known!"); ; 9'*w=V  
} UT^t7MY#O  
else if(nFileLength == -2) 3'.OghI  
{ Dri1A%  
System.err.println("File is not access!"); txL5' mK  
} <edAWc+  
else H%%#^rb^  
{ }"cb^3  
for(int i=0;i<nStartPos.length;i++) 2%@j<yS  
{ uF^+}Y ZT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Cch1"j<k$  
} mIr{Wocx  
for(int i=0;i<nEndPos.length-1;i++) 2r* o  
{ -Xd/-,zPY  
nEndPos = nStartPos[i+1]; WVo%'DtF`  
} ZE=~ re  
nEndPos[nEndPos.length-1] = nFileLength; ipbVQ7  
} [C d 2L&9  
} U9N}6a=  
}RoM N$r  
WQK#&r*  
//启动子线程 ;^ /9sLW?#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; n%?g+@y,^  
for(int i=0;i<nStartPos.length;i++) v-Br)lLv  
{ !-;Me&"I=`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tDi=T]-bt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), iT|+<h  
nStartPos,nEndPos,i); |]`+@K,S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s*!2oj  
fileSplitterFetch.start(); 9#3+k/A  
} }7C{:H2d  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5T;_k'qe  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Y.hrU*[J0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", I &m~ cBj<  
nEndPos = " + nFileLength); Az)P&*2:'`  
// fileSplitterFetch[nPos.length-1].start(); p jrA:;  
qi)(\  
Hu'c )|~f  
//等待子线程结束 |Y])|`_'G  
//int count = 0; 0dgR;Dl(  
//是否结束while循环 `i.f4]r  
boolean breakWhile = false; RCmPZ  
lv\2vRYw-  
OOv"h\,  
while(!bStop) O=-|b kO  
{ w1GCjD*y  
write_nPos(); 4 bJ3uIP#  
Utility.sleep(500); 2'x_zMV  
breakWhile = true; P!vBS "S  
~ib#x~Db  
t>25IJG  
for(int i=0;i<nStartPos.length;i++) f?{Y<M~]  
{ >"Hj=?  
if(!fileSplitterFetch.bDownOver) ,)QmQ ^/  
{ 8l}|.Q#--  
breakWhile = false; k5ZwGJ#r  
break; 3^fZUldf  
} !~mN"+u&  
} F`ihw[ Wn  
if(breakWhile) dyx 4_!fO  
break; Q \{\u J x  
pr m  
qt1# P  
//count++; qM9GW`CKA  
//if(count>4) f/ =0  
// siteStop(); ec3('}X  
} t7~mW$}O  
nY*ODL  
m?m,w$K  
System.err.println("文件下载结束!"); qQom=x  
} w?5b:W,  
catch(Exception e){e.printStackTrace ();} /vQ^>2X%  
} MDB}G '  
W5x]bl#  
UGN. ]#"#  
//获得文件长度 &R8zuD`#  
public long getFileSize() OE[/sv  
{ zO+nEsf^O  
int nFileLength = -1; Z os~1N]3  
try{ )WFUAzuN,  
URL url = new URL(siteInfoBean.getSSiteURL()); \u)(+t{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ("TI~  
httpConnection.setRequestProperty("User-Agent","NetFox"); |FNP~5v  
;N j5NB7  
2+^#<Uok  
int responseCode=httpConnection.getResponseCode(); C )P N  
if(responseCode>=400) ?Rwn1.Z  
{ :J<S-d=  
processErrorCode(responseCode); \e=@h!p  
return -2; //-2 represent access is error %v|,-B7Yx  
} My[L3KTTp  
J]~3{Mi  
eR}d"F4W  
String sHeader; k\%{1oRA  
'Gc6ZSLM  
%|u"0/  
for(int i=1;;i++) \Js9U|lY  
{ W35nnBU  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); a{8GT2h`4  
//Utility.log(in.readLine()); #?-W.  
sHeader=httpConnection.getHeaderFieldKey(i); F^w0TD8  
if(sHeader!=null) 'shOSB  
{ ]xS< \{og  
if(sHeader.equals("Content-Length")) x##Iv|$  
{ ce;9UBkOg2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7O{\^Jz1  
break; bcZHFX  
} \ 0CGS  
} `\qU.m0(j  
else ypsCyDQK`  
break; 2T|L# #C  
} Fdzd!r1 v  
} # ._!.P  
catch(IOException e){e.printStackTrace ();} @9L%`=]b^  
catch(Exception e){e.printStackTrace ();} WL7:22nSHa  
Jne)?Gt  
p*N+B o  
Utility.log(nFileLength); !^N/n5eoz  
!#X^nlc  
6^wiEnA  
return nFileLength; !",@,$  
}  CZuxH  
7i'vAOnw^  
lE`ScYG  
//保存下载信息(文件指针位置) dXOjaS# ~  
private void write_nPos() {6KU.'#iF  
{ ^@)+P/&  
try{ Y<|L|b6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); N-NwGD{  
output.writeInt(nStartPos.length); -x RsYYw  
for(int i=0;i<nStartPos.length;i++) ) wGC=,  
{ wF&\@H  
// output.writeLong(nPos); 0)84Z.k  
output.writeLong(fileSplitterFetch.nStartPos); vCi:c Ip/  
output.writeLong(fileSplitterFetch.nEndPos); foN;Q1?lS  
} 7kb`o y;(^  
output.close(); 2/bck)p=  
} m4%m0"Z  
catch(IOException e){e.printStackTrace ();} !Q?4sAB  
catch(Exception e){e.printStackTrace ();} 9 np<r82  
} jRBx7|ON  
'-*r&:  
~ugcfDJ  
//读取保存的下载信息(文件指针位置) 'fgDe  
private void read_nPos() mg 3jm  
{ !KF;Z|_(I  
try{ &"CS1P|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qItI):9U  
int nCount = input.readInt(); $4?%Z>'  
nStartPos = new long[nCount]; 5G2u(hx  
nEndPos = new long[nCount]; O_:Q#  
for(int i=0;i<nStartPos.length;i++) qH(2 0Z!  
{ o3`Z@-.G  
nStartPos = input.readLong(); q!7\`>.2:{  
nEndPos = input.readLong(); ?/u&U\P  
} x r=f9?%R  
input.close(); ;3-ssF}k*  
} TLkkB09fvk  
catch(IOException e){e.printStackTrace ();} f8n'9HOw>  
catch(Exception e){e.printStackTrace ();} zb3ir|  
} g-]td8}#  
& v`kyc  
v(0vP}[Q7E  
private void processErrorCode(int nErrorCode) pLIBNo?  
{ eygyVhJ  
System.err.println("Error Code : " + nErrorCode); ES+&e/G"ds  
} @.gCeMlOf  
.)o5o7H  
rXaL1`t*  
//停止文件下载 a@X'oV`(2b  
public void siteStop() Kzmgy14o  
{ X31kHK5F_  
bStop = true; "y`?KY$[N  
for(int i=0;i<nStartPos.length;i++) x0 #+yP  
fileSplitterFetch.splitterStop(); o]FQ)WRB  
EXzY4D ^  
fHgfI@{=j  
} v|e\o~2D`  
} _l  Jj6=  
//负责部分文件的抓取 WRnUF[y+)  
**FileSplitterFetch.java K}zw%!ex  
*/ >y=%o~  
package NetFox; w8on3f;6n#  
UC0 yrV  
$~2A o[  
import java.io.*; Ky=&C8b<  
import java.net.*; H4pjtVBr  
nQgn^z#  
B[*i}k%i  
public class FileSplitterFetch extends Thread { n1LS*-@  
\K4m~e@!  
Z,2uN!6  
String sURL; //File URL n2QD*3i  
long nStartPos; //File Snippet Start Position *7Mrng  
long nEndPos; //File Snippet End Position *zx;81X=  
int nThreadID; //Thread's ID /q^( uWu  
boolean bDownOver = false; //Downing is over EUNG&U  
boolean bStop = false; //Stop identical zL{KK9Or  
FileAccessI fileAccessI = null; //File Access interface ?LW1D+  
Z# :Ww  
}skXh_Vu4  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HS2)vd@)  
{ g"!B |  
this.sURL = sURL; 5yQgGd)  
this.nStartPos = nStart; lyT~>.?{  
this.nEndPos = nEnd; 5n"'M&Ce  
nThreadID = id; )PwDP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C{,nDa?|  
} ':fVb3A[*d  
fu|I(^NV  
rVO+ vhih  
public void run() L h0<A%  
{ D]0#A|n F  
while(nStartPos < nEndPos && !bStop) %++q+pa  
{ p'R}z|d)  
?$gEX@5h  
 mbd@4u  
try{ SAqX[c  
URL url = new URL(sURL); #\"5:.H Oz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @hCGV'4  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y/4B*>kl  
String sProperty = "bytes="+nStartPos+"-"; ~+1t 17  
httpConnection.setRequestProperty("RANGE",sProperty); APF-*/K?  
Utility.log(sProperty); [bZXzV(  
N#UyAm<9  
[#.QDe  
InputStream input = httpConnection.getInputStream(); ge E7<"m%  
//logResponseHead(httpConnection); VfQSfNsi  
9iv!+(ni  
}6o` in>M  
byte[] b = new byte[1024]; w+JDu_9+A]  
int nRead; EJRwyF5 LK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Bt.WRRpAB  
{ m7d? SU  
nStartPos += fileAccessI.write(b,0,nRead); 6.k2,C4dT<  
//if(nThreadID == 1) a|OX4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Bq\%]2;eo{  
} p{88v3b6  
}3QEclZr  
yYW>)  
Utility.log("Thread " + nThreadID + " is over!"); w 5,-+&;  
bDownOver = true; z S^:Ng5  
//nPos = fileAccessI.write (b,0,nRead); K)&AR*Tc  
} |{Oe&j3|  
catch(Exception e){e.printStackTrace ();} VkUMMq{  
} f>Ij:b`Z2  
} X)'uTf0  
C7nLa@  
i5rAb<q`  
//打印回应的头信息 b2ZKhS8  
public void logResponseHead(HttpURLConnection con) V RT| OUq  
{ |J8c|h<  
for(int i=1;;i++) 5I@< 6S&X  
{ vQ 5 p  
String header=con.getHeaderFieldKey(i); sqsBGFeG  
if(header!=null) \`x$@s?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qi$6y?  
Utility.log(header+" : "+con.getHeaderField(header)); {6RT&w  
else l.FkX  
break; uNLA/hL+n  
} 0b4QcfB1[  
} pWeKN`  
l].dOso$`  
O,hT< s "  
public void splitterStop() VBy=X\w]  
{ V:yia^1  
bStop = true; \]GBd~i<  
} k WF, *@.B  
)88z=5.  
)]?sCNb  
} XB^o>/|@S  
lor jMS  
C#+Gkzq  
/* }5u$/c@f1  
**FileAccess.java +Y6=;*j$  
*//文件访问(定位,写) O*X ]oX  
package NetFox; 'tklz*  
import java.io.*; Il,2^54q  
4Y;z46yM%  
5v6*.e'p  
public class FileAccessI implements Serializable{ ]haZT\  
%?^IS&]Z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X`ee}C.D_  
RandomAccessFile oSavedFile; Jzo|$W  
long nPos; >2tYw,m  
!T!U@e=u  
xhWWl(r`5  
public FileAccessI() throws IOException ,eW K~ pa  
{ JN,4#,  
this("",0); ^cn%]X#.  
} Il`35~a  
=# <!s!  
JgEPzHgx  
public FileAccessI(String sName,long nPos) throws IOException Se{}OG)  
{ /0A9d-Qd<  
oSavedFile = new RandomAccessFile(sName,"rw"); ]MKW5Kq  
this.nPos = nPos; XShi[7  
oSavedFile.seek(nPos); tZB" (\  
} p D-k<8|  
(_ HwU/  
,( u- x!  
public synchronized int write(byte[] b,int nStart,int nLen) )[oegfnn-  
{ N2#Wyt8MC  
int n = -1; b bCH(fYbu  
try{ *j6K QZ"  
oSavedFile.write(b,nStart,nLen); MAb*4e#  
n = nLen; m:SG1m_6  
} ;SnpD)x@)  
catch(IOException e) g 0O~5.f  
{ V"K-aO&  
e.printStackTrace (); Lyo!}T  
} D<U^FT  
?71?Vd  
T+1:[bqK  
return n; 69N/_V  
} `1 A,sXfa  
>}? jOB  
A{NKHn>%`  
} 4&N#d;ErC  
Pw+PBIGn4  
JbX"K< nQ  
/* Mu: y9o95  
**SiteInfoBean.java sE:~+C6o:  
*/ H{ M7_1T  
package NetFox; G5A:C(r  
J PO'1 D)  
.Q!_.LX  
public class SiteInfoBean { wr5ScsNS  
AS5' j  
2S,N9 (7  
private String sSiteURL; //Site's URL R RRF/Z;))  
private String sFilePath; //Saved File's Path !B|Aq- n,  
private String sFileName; //Saved File's Name iq1HA.X(  
private int nSplitter; //Count of Splited Downloading File .bYZkO:oy  
&X3G;x2;  
2i0 .x  
public SiteInfoBean() 3']a1\sy^  
{//nSplitter的缺省值为5 <$z6:4uN_  
//default value of nSplitter is 5 W>#[a %R  
this("","","",5); ahICx{hK  
} {#`O'F>  
(;!92ct[?  
{'#1do}{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  B_Ul&V  
{ wE3L,yx=  
sSiteURL= sURL; WwUhwY1o!L  
sFilePath = sPath; P aD6||1F  
sFileName = sName; (fA>@5n  
this.nSplitter = nSpiltter; d6^:lbj  
*jR4OY|DXH  
#B2a?   
} <?Ln`,Duk  
/Fk]>|*  
z( \4{Y  
public String getSSiteURL() M}fk[Yr>  
{ jlxY|;gZ-0  
return sSiteURL; YY zUg  
} b1TIVK3m  
]J1oY]2~  
yopC <k  
public void setSSiteURL(String value) =cR"_Z[8X  
{ 9\'JtZO  
sSiteURL = value; `' .;U=mF  
} HVdy!J  
CP'b,}Dd?I  
\E(^<Af  
public String getSFilePath() ~U r  
{ X;bHlA-g  
return sFilePath; y'5`Uo?\",  
} oyT`AYa  
6o0}7T%6  
&t~NR$@  
public void setSFilePath(String value) S;0z%$y  
{ n1U!od  
sFilePath = value; `5Bv2 wlIV  
} XL3m#zW&  
J Bgq2  
R 7h^ @  
public String getSFileName() [I?[N.v  
{ G! Y l0Zr  
return sFileName; 9])Id;+91  
} ,<=gPs;x  
)2 lB  
$l $p|  
public void setSFileName(String value) $d-$dM?R5  
{ 3D-0 N0o  
sFileName = value; w/z o  
} b/{$#[oP`  
s\zY^(v4  
3,'LW}  
public int getNSplitter() =Vm3f^  
{ a<0q%A x  
return nSplitter; ExhK\J  
} {'Y()p3kl  
' 7Mz]@  
Ze!/b|`xI  
public void setNSplitter(int nCount) GbC@ |  
{ BG6.,'~7o  
nSplitter = nCount; -5oYGLS$y3  
} 2 g\O/oz  
} *knN?`(x  
CNe(]HIOH  
kQ]4Bo  
/* 0&u=(;Dr\  
**Utility.java H_ a##z  
*/ 97[wz C,  
package NetFox; /lC,5y  
H:EK&$sU  
1M.#7;#B3  
public class Utility { 3@nIoN'z  
u/<ZGW(&s(  
;m7~!m)  
public Utility()  ,)uW`7  
{ * V7bALY  
^&\pY  
qnHjwMi  
} ]- 6q`'?[  
%"cOX  
//线程睡眠 k')H5h+Q=  
public static void sleep(int nSecond) nuDu  
{ 9@ 4]t6h[  
try{ x+DETRLP  
Thread.sleep(nSecond); ;GE6S{~-  
} d U*$V7  
catch(Exception e) \!hd|j?&6  
{ -Bq]E,Xf)  
e.printStackTrace (); x ;~;Ah.p  
} ;HBKOe_3  
} a x)J!I18  
pTaC$Ne  
//日志 |)v}\-\ #  
public static void log(String sMsg) mU(v9Jpf7  
{ rizjH+  
System.err.println(sMsg); MQDLC7Y.p5  
} 7O8 @T-f+2  
$}IG+ ,L  
2 FoLJ  
public static void log(int sMsg) ^62z\Y  
{ >0[:uu,'>  
System.err.println(sMsg); r@zs4N0WP  
} w2!:>8o:  
} |Eh2#K0x4G  
H0 Z o.Np  
bHcBjk.\  
/* </Y(4Xwf=  
**TestMethod.java c#CV5J\Kk3  
*/ Niu |M@  
package NetFox; -+u}u=z%  
7x77s  
`\|@w@f|;  
public class TestMethod { oOc-1C y  
dl3;A_ 2  
+*xc4  
public TestMethod() r`"T{o\e   
{ ///xx/weblogic60b2_win.exe %sPze]  
try{ wd32q7lGo1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {]U \HE1w  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [3sZ=)G  
SiteFileFetch fileFetch = new SiteFileFetch(bean); XZ{rKf2  
fileFetch.start(); CJh,-w{wJ"  
} /}2Y-GOU  
catch(Exception e){e.printStackTrace ();} F+*fim'NK  
t9MCT$U  
l.]wBH#RS  
} T{^P  
*/JYP +  
E%;$vj'2  
public static void main(String[] args) OiXO<1'$  
{ vE8BB$D  
new TestMethod(); %~k>$(u6  
} tl{{Vc[  
}  @)0  
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