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http断点续传简单实现(java)

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/* t7"vAjZU  
**SiteFileFetch.java u/5 ^N^@^  
*/ ^Gc#D:zU  
package NetFox; u dhj$:t  
import java.io.*; =@F1J7  
import java.net.*; "w#jC ~J<W  
,U\F <$O  
dvWQ?1l_  
public class SiteFileFetch extends Thread { OaeGukhX&  
`@$qy&AJ  
&&/2oP+z  
SiteInfoBean siteInfoBean = null; //文件信息Bean %jgB;Y  
long[] nStartPos; //开始位置 G1t{a:  
long[] nEndPos; //结束位置 Z= P]UD  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 i$GL]0  
long nFileLength; //文件长度 "enGWI H  
boolean bFirst = true; //是否第一次取文件 1'O++j_%y  
boolean bStop = false; //停止标志 EZ6\pyNB0#  
File tmpFile; //文件下载的临时信息 r2WW}W  
DataOutputStream output; //输出到文件的输出流 R/&Ev$:  
PyOj{WX>W  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) B:-qUuS?R  
public SiteFileFetch(SiteInfoBean bean) throws IOException h[|c?\E z  
{ Y7TW_[_u  
siteInfoBean = bean; n]?KDID;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {$,t^hd  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); u@V|13p<  
if(tmpFile.exists ()) oCw>b]S  
{ #GTR}|Aga  
bFirst = false; :qfP>Ok  
read_nPos(); i%M6$or  
} l[Hgh,  
else qD@]FEw!O  
{ _$g2;X >  
nStartPos = new long[bean.getNSplitter()]; tZW2TUM]  
nEndPos = new long[bean.getNSplitter()]; 2pKkg>/S  
} l70a&[W  
M0+xl+c+  
(n4\$LdP-  
p\A!"KC  
} ""0 cw  
_,,w>q6K  
#(i9G^K  
public void run() 6ol*$Q"z  
{ aYJTSgW  
//获得文件长度 ,~ z*V;y)  
//分割文件 O[$,e%  
//实例FileSplitterFetch Wu}84W"!.V  
//启动FileSplitterFetch线程 dF@m4U@L  
//等待子线程返回 /6K9? /  
try{ F.]D\"0`  
if(bFirst) pTQ70V3  
{ DJ zJ$Q  
nFileLength = getFileSize(); U ]o  
if(nFileLength == -1) yYdow.b!  
{ U*p;N,SjQ  
System.err.println("File Length is not known!"); r]sN I[  
} (_9u<  
else if(nFileLength == -2) hDn?R}^l{  
{ -o+<m4he  
System.err.println("File is not access!"); >cTSX  
} vYPZVqF_$  
else !R`E+G@   
{ tL>c@w#Pv  
for(int i=0;i<nStartPos.length;i++) Oq`CKf  
{ lG1\41ZxB  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;2k!KW@  
} [C>>j;q%  
for(int i=0;i<nEndPos.length-1;i++) vtA%^~0  
{ *eF'<._[U  
nEndPos = nStartPos[i+1]; (9]8r2|.  
} 3J3Yt`  
nEndPos[nEndPos.length-1] = nFileLength; ^t 2b`n60  
} "mtEjK5  
} }zO>y%eI  
\aY<| 7zK  
_9pcHhJux  
//启动子线程 x\i+MVR-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >WcOY7  
for(int i=0;i<nStartPos.length;i++) qexnsL  
{ Qo5yfdR  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ib&]1ger#=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >d9b"T  
nStartPos,nEndPos,i); _?I6[Mz  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y),yks?iv  
fileSplitterFetch.start();  >7$h  
} L=_   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JeXA*U#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !r#36kO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1C5~GI`  
nEndPos = " + nFileLength); hU~up a<dD  
// fileSplitterFetch[nPos.length-1].start(); 4}r.g0L  
h`@z61UI  
U&'Xs z  
//等待子线程结束 = j!nt8]8  
//int count = 0; tt03 gU`  
//是否结束while循环 ml1My1  
boolean breakWhile = false; X 2Zp @q(  
H?4t\pSS  
,{jF)NQaP  
while(!bStop) 0PdX>h.t  
{ $lAQcG&Q  
write_nPos(); .P(A x:g  
Utility.sleep(500); [KW9J}]  
breakWhile = true; Da)H/3ii  
U:fGIEz{ZY  
rNl%I@G  
for(int i=0;i<nStartPos.length;i++) S rom@c  
{ 3>#io^35  
if(!fileSplitterFetch.bDownOver) h @2.D|c)g  
{ ] A,Og_g  
breakWhile = false; ] ]lN[J  
break; El^V[s'3  
} KP xf  
} FfM,~s<Efz  
if(breakWhile) LJwy,-  
break; rebWXz7  
Ol)M0u  
`s\E"QeZN  
//count++; THcX.%ToT  
//if(count>4) /_V4gwb}|-  
// siteStop(); D9r4oRkP*  
} d:g0XP  
2Xqa?ay0>  
|o#pd\  
System.err.println("文件下载结束!"); mc|8t0+1`  
} X8 A$&  
catch(Exception e){e.printStackTrace ();} {S"!c.  
} %&M*G@j  
Y.#:l<  
=PmIrvr'[5  
//获得文件长度 Og:aflS  
public long getFileSize() _53N uEM1  
{ ;edt["Eu  
int nFileLength = -1; |D~#9  
try{ w^)_Fk3  
URL url = new URL(siteInfoBean.getSSiteURL()); -"x25~k!?F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); DxzNg_E]  
httpConnection.setRequestProperty("User-Agent","NetFox"); B18?)LA  
@WuG8G  
8M6Qn7{L  
int responseCode=httpConnection.getResponseCode(); r~;TId} #  
if(responseCode>=400) (2'q~Z+>'  
{ RsnFjfb'  
processErrorCode(responseCode); o(Q='kK  
return -2; //-2 represent access is error ~?:Xi_3Lo  
} dRXdV7-!  
dk@iAL*v  
 m8z414o  
String sHeader; l/6(V:  
Yp6% @c6\  
$m0-IyXcv  
for(int i=1;;i++) 3NlG,e'T2  
{ rB-}<22.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); e%v0EJ},  
//Utility.log(in.readLine()); b)+;@wa~  
sHeader=httpConnection.getHeaderFieldKey(i); !kWx'tJ$  
if(sHeader!=null) )Zit6I  
{ ziG]BZ  
if(sHeader.equals("Content-Length")) TuMD+^x  
{ \j~LxV  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); SkMBdkS9z[  
break; ul ag$ge  
} B{-+1f4  
} Z=y^9]  
else E@S5|CM  
break; ?KXgG'!!  
} few=`%/  
} mx")cGGQ  
catch(IOException e){e.printStackTrace ();} tCbn B  
catch(Exception e){e.printStackTrace ();} = ms o1  
D3kx&AR  
`|g*T~; kC  
Utility.log(nFileLength); U\`H0'  
A]mXV4RmI  
gj<Y+Dv>  
return nFileLength; Vv5#{+eT;  
} ]QK@zb}x  
So\f [/em  
a>/jW-?  
//保存下载信息(文件指针位置) Q.`O;D}x  
private void write_nPos() :Y>M/ /0  
{ E/N*n!sV  
try{ *kWrF* )J  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ex3V[v+D(  
output.writeInt(nStartPos.length); hu''"/raM  
for(int i=0;i<nStartPos.length;i++) d!]fou  
{ VLfE3i4Vwl  
// output.writeLong(nPos); {Tym#  
output.writeLong(fileSplitterFetch.nStartPos); 4'ymPPY  
output.writeLong(fileSplitterFetch.nEndPos); vTF_`X  
} f;PvXq<7"  
output.close(); ^qD@qJ  
} qX?k]m   
catch(IOException e){e.printStackTrace ();} v5!G/TZ1  
catch(Exception e){e.printStackTrace ();} _N&]w*ce  
} 9x0Ao*D<t  
]$gBX=  
p4-bD_  
//读取保存的下载信息(文件指针位置) 1Ev#[FOc  
private void read_nPos() -U/m  
{ 9e:}q O5)  
try{ q[w.[]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); dJ0qg_ U&  
int nCount = input.readInt(); U~e^  
nStartPos = new long[nCount]; < BNCo5*  
nEndPos = new long[nCount]; NFQR  
for(int i=0;i<nStartPos.length;i++) j. L`@  
{ !@<>S>uGG  
nStartPos = input.readLong(); 47c` ) *Hc  
nEndPos = input.readLong(); M~1 n#  
}  #FfUkV  
input.close(); {} 11U0  
} }m6j6uAR6)  
catch(IOException e){e.printStackTrace ();} n xc35  
catch(Exception e){e.printStackTrace ();} C/!c?$J  
} n^7$ST#'bV  
3g#fX{e_5!  
%hu] =  
private void processErrorCode(int nErrorCode) )@]Y1r4U  
{ *&vySyt  
System.err.println("Error Code : " + nErrorCode); gTp){  
} ){.J`X5r  
'e(`2  
+I?T|Iin  
//停止文件下载 lilKYrUmG  
public void siteStop() 96.A8o  
{ J6H3X;vxQw  
bStop = true; nFn@Z'T$N  
for(int i=0;i<nStartPos.length;i++) \gE3wmSJ,  
fileSplitterFetch.splitterStop(); :W/,V^x}  
xCd9b:jG  
 jJjD)  
} Y(D@B|"'m  
} cN>z`x l  
//负责部分文件的抓取 Z81{v<c;  
**FileSplitterFetch.java pEjA*6v|,  
*/ xpf\S10e  
package NetFox; jF'azlT  
ZcXqH7`r  
'CDRb3w}B  
import java.io.*; !Z7 ~R sdm  
import java.net.*; 1f 0"z1   
k MS[   
4:=eO!6  
public class FileSplitterFetch extends Thread { (YjY=F  
iz`u@QKc%  
&8Cuu$T9)  
String sURL; //File URL k!]Tg"]JAh  
long nStartPos; //File Snippet Start Position '\:?FQ C  
long nEndPos; //File Snippet End Position \^wI9g~0  
int nThreadID; //Thread's ID edPnC {?s  
boolean bDownOver = false; //Downing is over Riq5Au?*)  
boolean bStop = false; //Stop identical =;{vfjj  
FileAccessI fileAccessI = null; //File Access interface n8zh;vuJ  
m7 !Fb  
x C'>W"pY  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~9qDmt,i  
{ P 7 [p$Z  
this.sURL = sURL; cI3uH1;#  
this.nStartPos = nStart; 0\AYUa?RM  
this.nEndPos = nEnd; %ma1LN[  
nThreadID = id; #Dx$KPD  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7581G$@ym  
} voaRh@DZ%/  
5|:=#Ql*  
Mg95us  
public void run() .1MXQLy  
{ M`umfw T  
while(nStartPos < nEndPos && !bStop) /Mf45U<  
{ ~ K^Z4  
T7n;Bf  
SSi}1  
try{ oZ%t!Fl1  
URL url = new URL(sURL); 4;|&}Ij  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >k^=+  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1K,bmb xRt  
String sProperty = "bytes="+nStartPos+"-"; NF0} eom  
httpConnection.setRequestProperty("RANGE",sProperty); P G) dIec  
Utility.log(sProperty); 4 !~JNO  
FFH-Kw,  
SR~~rD|V  
InputStream input = httpConnection.getInputStream(); g{l;v  
//logResponseHead(httpConnection); T:wd3^.CG  
hW>@jT"t1C  
RKIqg4>E  
byte[] b = new byte[1024]; Oa7`Y`6  
int nRead; P 2;j>=W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~z>2`^Z"  
{ L<QqQ"`  
nStartPos += fileAccessI.write(b,0,nRead); WJe  
//if(nThreadID == 1) &e_M \D  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yXrFH@3  
} )y.J2_lI8  
if:2sS9r  
S! ,.#e(Y  
Utility.log("Thread " + nThreadID + " is over!"); x1+8f2[  
bDownOver = true; kY xn5+~  
//nPos = fileAccessI.write (b,0,nRead); 9+=U&*  
} ]Rnr>_>x;  
catch(Exception e){e.printStackTrace ();} b)$<aFl  
} 7Y @ &&  
} Uh?SDay  
wp.<}=|u  
h{J2CWJ  
//打印回应的头信息 InNuK0@  
public void logResponseHead(HttpURLConnection con) Lc+wS@  
{ -UPdgZ_Vxz  
for(int i=1;;i++) 8K6yqc H  
{ 292e0cE  
String header=con.getHeaderFieldKey(i); 7qgHH p  
if(header!=null) "-A@>*g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cRT@Cu  
Utility.log(header+" : "+con.getHeaderField(header)); M*8Ef^-U`t  
else ?8b?{`@V  
break; q%Obrk  
} ?J6J#{LRd  
} Mh[;E'C6  
5sFp+_``  
EmVE<kY .  
public void splitterStop() <.s[x~b\`  
{ ^0ipM/Lg  
bStop = true; z[}[:H8  
} vM1f-I-  
)g9Zw_3  
F^3Q0KsT  
} DE^{8YX,  
:JxShF:M  
b,]h X  
/* ; R&wr _%  
**FileAccess.java bh3}[O,L A  
*//文件访问(定位,写) N'i%9SBcg  
package NetFox; JN$v=Ox{  
import java.io.*; D7olu29  
Q(T)s  
+ ( `  
public class FileAccessI implements Serializable{ jL6u#0  
!G 90oW  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 506B =  
RandomAccessFile oSavedFile; a:XVu0`(  
long nPos; m@u!frE,  
1*Yf[;L  
YRfs8I^rg  
public FileAccessI() throws IOException O1ofN#u  
{ ZXY5Xvt:v  
this("",0); x$[<<@F%  
} ^}8(o  
SWN i@  
`kpX}cKK}  
public FileAccessI(String sName,long nPos) throws IOException D}>pl8ke~g  
{ ` {gkL-  
oSavedFile = new RandomAccessFile(sName,"rw"); E!8FZv8  
this.nPos = nPos; k?;A#L~  
oSavedFile.seek(nPos); C\ZL*,%}  
} &BY%<h0c  
h q6B pE  
me_DONW  
public synchronized int write(byte[] b,int nStart,int nLen) [2pp)wq  
{ ms{:=L2$$  
int n = -1; 1XSA3;ZEc  
try{ GbFLu`Iu  
oSavedFile.write(b,nStart,nLen); *p`0dvXG2  
n = nLen; `MA ee8u'  
} ?l! L )!2  
catch(IOException e) l"5$6h  
{ 6}='/d-[  
e.printStackTrace (); :9Zu&t  
} F[<EXLQ  
L(\sO=t  
>6*"g{/  
return n; <W~5;m  
} [R+zzl&Zw  
bW(+Aw=O  
nd3=\.(P  
} *%l&'+   
h!5^d!2,  
O#  .^}  
/* 9 yH95uaDF  
**SiteInfoBean.java ]W7(}~m  
*/ 8 !Pk1P  
package NetFox; WMnR+?q  
kT@RA}  
R $HI JM  
public class SiteInfoBean { h#'(i<5v  
U_v{Vs  
C7[ge&  
private String sSiteURL; //Site's URL @'C f<wns  
private String sFilePath; //Saved File's Path \kqa4{7U(  
private String sFileName; //Saved File's Name W{O:j  
private int nSplitter; //Count of Splited Downloading File -}`ES]  
vDZhoD=VR  
k$UgTZ  
public SiteInfoBean() `2c>M\c4U  
{//nSplitter的缺省值为5 Qj5~ lX`W  
//default value of nSplitter is 5 R#i|n< x  
this("","","",5); AVVL]9b_2  
} EF=.L{  
aDFu!PLB{)  
b }S}OW2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J\<7M8   
{ |={><0  
sSiteURL= sURL; /%C6e )7BL  
sFilePath = sPath; rLs)*A!  
sFileName = sName; jXvGL  
this.nSplitter = nSpiltter; 0JQy-hpF  
Gc>bli<-  
WJ=DTON  
} tRRPNY  
c|3%0=,`  
_/bFt6  
public String getSSiteURL() TWYz\Hmw  
{ K]' 84!l  
return sSiteURL; )QE7$|s  
} 3#huC=zbf  
r7Bv?M^!  
 G7 >  
public void setSSiteURL(String value) Qw4P{>|Y  
{ J01w\#62pQ  
sSiteURL = value; KY H*5  
} GdG1e%y]z  
 hLFf  
dQ?4@  
public String getSFilePath() Be}e%Rk  
{ n={} ='  
return sFilePath; F{)YdqQ  
} C-d|;R}Ww  
ozH7c_ <  
WRU/^g3O@'  
public void setSFilePath(String value) %])-+T  
{ 6~zR(HzV{  
sFilePath = value; ta"/R@ k*  
} ,!t1( H  
IK5FSN]s/  
5w"f.d'  
public String getSFileName() Ol H{!  
{ L;/#D>U(  
return sFileName; g0Qg]F5D~  
} #Z<pks2 y  
bcL>S$B  
p 7IJ3YY  
public void setSFileName(String value) !Sr^4R+Z  
{ j[NA3Vj1P  
sFileName = value; u{0+w\xH\  
} k1Zu&4C\  
d,[.=Jqv[  
H6E@C}cyM  
public int getNSplitter() Ag}V>i'  
{ rubqk4  
return nSplitter; u^a\02aV[  
} >"?HbR9  
0CS^S1/[B`  
HRIf)n&~f  
public void setNSplitter(int nCount) F7a &-  
{ Nge_ Ks  
nSplitter = nCount; qY\zZ  
} ;y<)RM  
} idnn%iO  
SF+ ^dPwj  
pC(AM=RY!  
/* $de_>  
**Utility.java ?2[=llS4  
*/ ^|xj.  
package NetFox; +A8S 6bA[=  
PN2\:l+`  
KIn^,d0H  
public class Utility { TFbCJ@X  
7p3 ;b"'  
toPA@V  
public Utility() v}A] R9TY  
{ +P|$T:b  
PN/2EmwtC  
p9R`hgx  
} *{W5QEa  
w3Aq[1U0  
//线程睡眠 1pXAPTV  
public static void sleep(int nSecond) j^KM   
{ efMv1>{  
try{ o;FjpZ  
Thread.sleep(nSecond); N;A1e@bP  
} 9Q=g]int u  
catch(Exception e) "A__z|sQ  
{ N\H{p %8  
e.printStackTrace (); \|R`wFn^P  
} RTA9CR)JP4  
} s .^9;%@$J  
6`NsX  
//日志 IaE};8a8  
public static void log(String sMsg) ,!kyrk6  
{ 0'^? m$  
System.err.println(sMsg); 6#N1 -@  
} *bn9j>|iv  
y>2v 9;Qp  
w|Zq5|[  
public static void log(int sMsg) QC4_\V>[  
{ U,iTURd  
System.err.println(sMsg); WSDNTfpI  
} >~BU<#  
} ZeWHSU  
\'E_  
Q C~~  
/* ,-] JCcH  
**TestMethod.java =6  
*/ ]*i>KR@G  
package NetFox; ddnWr"_  
2_r}4)z  
5 1 x^gX|  
public class TestMethod { iCAd7=o  
7azxqa5:  
h^hEyrJw  
public TestMethod() <@*mFq0,  
{ ///xx/weblogic60b2_win.exe 7MGc+M(p  
try{ `9K'I-hv<8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); GmAE!+"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9D<^)ShY  
SiteFileFetch fileFetch = new SiteFileFetch(bean); J\;~(: ~  
fileFetch.start(); e1<28g  
} =[1 W.Zt  
catch(Exception e){e.printStackTrace ();} ` |]6<<'iW  
y]?$zbB  
Fof_xv9  
} X]1ep  
t9K.Jc0  
,{oP`4\Lm  
public static void main(String[] args) L~mL9[(,  
{ (Nik( Oyj"  
new TestMethod(); 8L=QfKr  
} uxh4nyE  
} n]j(tP  
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