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http断点续传简单实现(java)

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/* '.=Wk^,Ua  
**SiteFileFetch.java iTj"lA  
*/ UY1JB^J$  
package NetFox; YCirOge  
import java.io.*; @47[vhE  
import java.net.*; )>-77\  
J'I1,5(  
m(8jSGV  
public class SiteFileFetch extends Thread { cBg,k[,  
:= ]sq}IN  
JmnBq<&,0  
SiteInfoBean siteInfoBean = null; //文件信息Bean R)sp  
long[] nStartPos; //开始位置 |\i:LG1  
long[] nEndPos; //结束位置 V"w`!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -iY9GN89c  
long nFileLength; //文件长度 }pbBo2  
boolean bFirst = true; //是否第一次取文件 w> Tyk#7lw  
boolean bStop = false; //停止标志 IXbdS9,>F  
File tmpFile; //文件下载的临时信息 k&MlQ2'!<  
DataOutputStream output; //输出到文件的输出流 ?BWHr(J  
M(_^'3u  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) (45NZBs  
public SiteFileFetch(SiteInfoBean bean) throws IOException <QYCo1_  
{ A/ 7r:yO  
siteInfoBean = bean; gJ<@;O8zu0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @SKO~?7T  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Y1$#KC  
if(tmpFile.exists ()) sN6 0o 7.  
{ )?!vJb"  
bFirst = false; MV Hz$hyB  
read_nPos(); "z^BKb5  
} 2$o2.$i81  
else 1zh$IYrd  
{ 4w;r l(s  
nStartPos = new long[bean.getNSplitter()]; B rez&3[  
nEndPos = new long[bean.getNSplitter()]; 8O"x;3I9  
} 34X(J-1\|i  
f}L>&^I)  
${jA+L<J  
Kj~>&WU  
} XR{5]lKt_  
yq/[/*7^  
7xLo 4  
public void run() }9L 40)8  
{ 4]Un=?)I  
//获得文件长度 Paae-EmC  
//分割文件 )ZS:gD  
//实例FileSplitterFetch K*([9VZ  
//启动FileSplitterFetch线程 _7-"Vo X  
//等待子线程返回 W HlD %u  
try{ ^2&O3s  
if(bFirst) O!#L#u53  
{ \SYPu,ZT  
nFileLength = getFileSize(); <7vIh0  
if(nFileLength == -1) ",MK'\E  
{ ()+jrrK  
System.err.println("File Length is not known!"); W /~||s  
} w,M1`RsK  
else if(nFileLength == -2) L#t-KLJ  
{ o{ ,ba~$.w  
System.err.println("File is not access!"); R-g>W  
} M!xm1-,[  
else (hhdbf  
{ 5@w'_#!)  
for(int i=0;i<nStartPos.length;i++) <Z\MZ&{k{*  
{ xm<5S;E5U4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "-0pz\a  
} vR6^n~  
for(int i=0;i<nEndPos.length-1;i++) pl jV|.?  
{ ]ro1{wm!WU  
nEndPos = nStartPos[i+1]; x?k  
} A^T~@AO  
nEndPos[nEndPos.length-1] = nFileLength; #U ",,*2  
} "sX [p  
} DuTlYXM2^  
 2.HZ+1  
*@-q@5r}!  
//启动子线程 4=?Ok":8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8>%jZ%`a  
for(int i=0;i<nStartPos.length;i++) /{eih]`x(  
{ ,wry u|7"$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;[WSf{k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O4b-A3:  
nStartPos,nEndPos,i); 9E->;0-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H3p4,Y}'#  
fileSplitterFetch.start(); g(@$uJ  
} ^Ff~j&L@{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y]z)jqX<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?1-n\ka  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", aIzp\$NWVK  
nEndPos = " + nFileLength); [#STR=_f  
// fileSplitterFetch[nPos.length-1].start(); )+jK0E1  
g9FVb7In_  
eI/\I:G{f  
//等待子线程结束 Rk437vQD,  
//int count = 0; \dp9@y[^  
//是否结束while循环 'gk81@|  
boolean breakWhile = false; zJy 89ib'  
h+zkVRyA  
v$.JmL0^J  
while(!bStop) "lv:hz  
{ 94qHY1rp  
write_nPos(); brYYuN|Vc  
Utility.sleep(500); Ru  vG1"  
breakWhile = true; j(@g   
O5G<O(,\  
}C`}wS3i  
for(int i=0;i<nStartPos.length;i++) RAD4q"}k  
{ X-G~/n-x  
if(!fileSplitterFetch.bDownOver) ])$. "g  
{ s0`|G|.}  
breakWhile = false; ={mPg+Ei'  
break; j &0fC!k  
} =E"kv!e   
} m>Z\ rqOK  
if(breakWhile) Ul$X%  
break; ig.6[5a\  
.^)C:XiW  
LAK-!!0X  
//count++; !Z+*",]_  
//if(count>4) 5ykk11!p$  
// siteStop(); U'h[ {ek  
} )L(d$N=Bd  
'n>3`1E,  
J1c&"Oh  
System.err.println("文件下载结束!"); lkSz7dr@  
} (8@h F#N1  
catch(Exception e){e.printStackTrace ();} [F AOp@7W  
} lE2wkY9^/  
[)J49  
Vlp*'2VO  
//获得文件长度 L?D~~Jb  
public long getFileSize() iZkW+5(  
{ ~-`BSR  
int nFileLength = -1; `%mBu`A  
try{ p~d)2TC4#  
URL url = new URL(siteInfoBean.getSSiteURL()); }VGI Y>v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u':0"5}  
httpConnection.setRequestProperty("User-Agent","NetFox"); :m)Rmwn_  
E-tNB{r@  
+Qi52OG  
int responseCode=httpConnection.getResponseCode(); }TX'Z?Lq  
if(responseCode>=400) D|Ihe%w-  
{ +SuUI-.  
processErrorCode(responseCode); ku[=QsMv  
return -2; //-2 represent access is error x3I%)@-Z  
} c~pUhx1(  
,Zcx3C:#  
tXG4A$(2&  
String sHeader; Hs4zJk  
P^_d$  
r"u(!~R  
for(int i=1;;i++) 'Qs 3  
{ !s[j1=y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6(<~1{ X%  
//Utility.log(in.readLine()); iM\ Z J6  
sHeader=httpConnection.getHeaderFieldKey(i); Y9H *S*n  
if(sHeader!=null) ev;5 ?9\E  
{ tN'- qdm  
if(sHeader.equals("Content-Length")) O%++0k;  
{ Pdo5 sve  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {HRxyAI!  
break; A^r [_dyZ  
} *F8 uu.  
} C!/8e (!N  
else ".Deu|>  
break; ^?^|Y?f2P?  
} dn)tP6qc/  
} J\dhi{0  
catch(IOException e){e.printStackTrace ();} k+Ma_H`  
catch(Exception e){e.printStackTrace ();} G$x["  
QhE("}1  
rD(ep~^M  
Utility.log(nFileLength); Dpp52UnT E  
Ng;b!S  
d$?n6|4  
return nFileLength; ,f /IG.  
} _"w!KNX>(~  
++{+ #s6  
T\e)Czz2-  
//保存下载信息(文件指针位置) WfjUJw5x"s  
private void write_nPos() _KkVI7a  
{ x4m_(CtK  
try{ :J4C'N  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "w|k\1D  
output.writeInt(nStartPos.length); Ppb2"Ik  
for(int i=0;i<nStartPos.length;i++) seD+~Y\z  
{ xX4^nem\G  
// output.writeLong(nPos); z`r4edk3  
output.writeLong(fileSplitterFetch.nStartPos); *}iT6OJ  
output.writeLong(fileSplitterFetch.nEndPos); Wn,g!rB^@  
} o2e h)rtB  
output.close(); Ko]h r  
} EPd.atA  
catch(IOException e){e.printStackTrace ();} U5ud?z()OA  
catch(Exception e){e.printStackTrace ();} {}_Oo%IVGK  
} n,Mw# r?y  
Y)j,(9  
5$"[gdt)T  
//读取保存的下载信息(文件指针位置) ={i&F  
private void read_nPos() +$mskj0s  
{ ]MA)=' ~  
try{ bQN4ozSi  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); f+*2K^B  
int nCount = input.readInt(); O"-PNF,J  
nStartPos = new long[nCount]; _467~5JkU  
nEndPos = new long[nCount]; &\]f!'jV  
for(int i=0;i<nStartPos.length;i++) \=G Xe.}4d  
{ z Q|x>3   
nStartPos = input.readLong(); U/&qV"Ih  
nEndPos = input.readLong(); VQNH@g^gqr  
} owY_cDzrH  
input.close(); \7tvNa,C  
} 0!'M#'m  
catch(IOException e){e.printStackTrace ();} 7/OOq=z  
catch(Exception e){e.printStackTrace ();} o(SJuZC/U  
} Z-p^3t'{  
&lfF!   
Pymh^i  
private void processErrorCode(int nErrorCode) l'{goyf  
{ Y)5uK:)^  
System.err.println("Error Code : " + nErrorCode); nPIR 1Z  
} 4!s k3Cw{  
e"H+sM26-  
i K[8At"Xo  
//停止文件下载 Di1G  
public void siteStop() B l/e>@M  
{ z` ?xS  
bStop = true; Rw=E_q{  
for(int i=0;i<nStartPos.length;i++) , G/X"t ~  
fileSplitterFetch.splitterStop(); jeBj   
I/-w65J]  
CY).I`aJ  
} z`:^e1vG  
} gGdYh.K&e5  
//负责部分文件的抓取 awW\$Q  
**FileSplitterFetch.java `M<G8ob  
*/ S"A_TH  
package NetFox; C`_D{r  
:@8.t,|  
! tPK"k  
import java.io.*; 1:s~ ]F@  
import java.net.*; :8L61d2(  
gV44PI6h  
9*Twx&  
public class FileSplitterFetch extends Thread { m1; <T@  
k 5r*?Os  
v;qL? _:=c  
String sURL; //File URL vHe.+XY  
long nStartPos; //File Snippet Start Position F"#*8P  
long nEndPos; //File Snippet End Position WIl S^?5I<  
int nThreadID; //Thread's ID J& SuUh<  
boolean bDownOver = false; //Downing is over z}N^`_ *  
boolean bStop = false; //Stop identical ~4` ec   
FileAccessI fileAccessI = null; //File Access interface yWk:u 5  
C)^\?DH  
vCo}-b-j  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^g){)rz|  
{ p;Ok.cXVp  
this.sURL = sURL; 0 S8{VZpy  
this.nStartPos = nStart; ;RZa<2  
this.nEndPos = nEnd; ^a5~FI:  
nThreadID = id; jtpNo~O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &'2l_b  
} kV%y%l(6  
,^66`C[G  
P3FpU<OBwp  
public void run() 2m}]z.w#  
{ 2xBGs9_Y  
while(nStartPos < nEndPos && !bStop) JJOs L!@  
{ |Qq'_4:  
^n5QK HD  
[c%}L 3B  
try{ g8@HAV^H  
URL url = new URL(sURL); \/%Q PE8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .%h_W\M<l  
httpConnection.setRequestProperty("User-Agent","NetFox"); U]&%EqLS  
String sProperty = "bytes="+nStartPos+"-"; mYRR==iDL  
httpConnection.setRequestProperty("RANGE",sProperty); r~a}B.pj  
Utility.log(sProperty); [/^g) ^s:  
m,_oX1h  
o |.me G  
InputStream input = httpConnection.getInputStream(); b|'LtL$Y  
//logResponseHead(httpConnection); jXva ?_  
gz:c_HJ  
S%|' /cFo  
byte[] b = new byte[1024]; sW`iXsbWM>  
int nRead; OVK(:{PwS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y mSaIf  
{ 2uB26SEIl  
nStartPos += fileAccessI.write(b,0,nRead); udr'~,R  
//if(nThreadID == 1) U.)eJ1a  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "d*  
} dQ o$^?  
ht!:e>z&4  
goWt!,&f  
Utility.log("Thread " + nThreadID + " is over!"); }E_zW.{!  
bDownOver = true; j+v)I=  
//nPos = fileAccessI.write (b,0,nRead); 7cSvAX0Z.  
} 0drc^rj !  
catch(Exception e){e.printStackTrace ();} >CA1Ub&ls  
} M/ \~  
} BNLall  
SK2pOZN  
v3]M;Y\  
//打印回应的头信息 N#qoKY(#  
public void logResponseHead(HttpURLConnection con) wOSNlbQ5jl  
{ #jR?C9&!(  
for(int i=1;;i++) nI` 1@ vB&  
{ ,peFNpi  
String header=con.getHeaderFieldKey(i); 0(.C f.B~  
if(header!=null) of<OOh%3  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); DvKMb-*S  
Utility.log(header+" : "+con.getHeaderField(header)); C u5 - w  
else \Bf{/r5x  
break; [#V! XdQ,  
} 3 g!h4?^  
} {<Zqw]  
)v.FAV:  
+<#-52br\  
public void splitterStop() #7)6X:/O  
{ 7wiu%zfa:=  
bStop = true; riQ?'!a7  
} HxAa,+k  
z(` kWF1<  
OTm"Iwzu@  
} Ds$;{wl#x  
F U%b"gP^  
6 >2! kM7  
/* D=+sD"<|  
**FileAccess.java 7X"cu6%\  
*//文件访问(定位,写) JD .z}2+  
package NetFox; kSrzIq<xre  
import java.io.*; 7hQl,v< 5  
awtzt?VtLh  
'McVaPav  
public class FileAccessI implements Serializable{ [ ff.R  
A#{*A  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o! N@W  
RandomAccessFile oSavedFile; *0tNun 5=3  
long nPos; r>OE[C69  
CK%W +";  
TlJF{ <E  
public FileAccessI() throws IOException UJ+JVj   
{ _7VU ,  
this("",0); 2I5@zm ea  
} MDZb|1.AT  
MiI7s ;  
UHwrssX&3  
public FileAccessI(String sName,long nPos) throws IOException $$w 1%#F =  
{ NjLd-v"2  
oSavedFile = new RandomAccessFile(sName,"rw"); ^YV[1~O  
this.nPos = nPos; < XU]%}o  
oSavedFile.seek(nPos); "O{sdVS  
} G"(!5+DLy  
4H)a7 <,  
W\.(~-(So  
public synchronized int write(byte[] b,int nStart,int nLen) .FyC4"b=c  
{ U/;Vge8{  
int n = -1; 1>LquZ+Kj  
try{ scmb DaOn  
oSavedFile.write(b,nStart,nLen); %\u>%s <9  
n = nLen; "@_f>3z  
} ?uLqB@!2  
catch(IOException e) v,! u{QP  
{ iW)Ou?aS  
e.printStackTrace (); .T2I]d  
} {WChD&v  
~V5jjx*  
;F- kE4w  
return n; s5 BV8 M  
} ~PHG5?X  
c'C2V9t  
NoT oLt\  
} lH 8?IkK,g  
CS  
F~6[DqF\|  
/* W0Vjs|/  
**SiteInfoBean.java 78kk"9h'  
*/ X|:O`b$G  
package NetFox; $0 )K [K  
@,hvXl-G*  
`O F\f  
public class SiteInfoBean { 43YusUv  
+|N"i~f>j  
rx<fjA%  
private String sSiteURL; //Site's URL ftbu:RtK^^  
private String sFilePath; //Saved File's Path @r<w|x}  
private String sFileName; //Saved File's Name !|]%^G  
private int nSplitter; //Count of Splited Downloading File bZ=d!)%P-{  
}j QwP3eY  
QH eUpJ/^  
public SiteInfoBean() u<[Y6m  
{//nSplitter的缺省值为5 l%fl=i~oN  
//default value of nSplitter is 5 >8c9-dTmf  
this("","","",5); 4f+Ke*^[RA  
} xE:p)B-]  
:v+ 39  
zB4gnVhus|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) juM?y'A  
{ &j$k58mX  
sSiteURL= sURL; o{/D:B  
sFilePath = sPath; %%#zO Z  
sFileName = sName; 5E]I  
this.nSplitter = nSpiltter; %NuS!v>  
Sn0 Gw  
y~w$>7U.  
} %~@}wHMB  
S&yCclM  
Xv6s,<#\  
public String getSSiteURL() 5_PD ?lg  
{ KpWQ;3D2  
return sSiteURL; g]S.u8K8m  
} DY%E&Vd:h  
'<O& :  
-7u4f y{T  
public void setSSiteURL(String value) K=;p^dE  
{ KQh'5o&  
sSiteURL = value; D`+'#%%x  
} JA&w"2X*E  
%*,'&S  
0 I,-1o|s  
public String getSFilePath() %NKf@If)  
{ d)LifsD)  
return sFilePath; ~FJd{$2x`  
} u(P D+Gz  
,JR7N_"I  
B<W{kEY  
public void setSFilePath(String value) 2`x[y?Tn  
{ 3a =KgOvp  
sFilePath = value; NVQ IRQ.  
} r__uPyIMG/  
?>e-6*.  
lUDzf J}3  
public String getSFileName() h_J 'dJS  
{ ,oR}0(^"\<  
return sFileName; ,>)/y  
} EBJaFz'  
r>5,U:6Q/  
*@dqAr%  
public void setSFileName(String value) SJL?(S*  
{ C{4[7  
sFileName = value;  RszqDm  
} Pr" 2d\  
B?k75G  
\ ^_3Yw  
public int getNSplitter() YS &3+Tp  
{ v~j21`  
return nSplitter; |]V0sgpoZ  
} \S _ycn  
(@]{=q<  
"gYn$4|R7*  
public void setNSplitter(int nCount) zXB.)4T  
{ 3(X"IoNQ  
nSplitter = nCount; lbMb  
} ">|fB&~A  
} iCx}v[;Ol  
AFyf7^^k  
VCtj8hKDr  
/* kd2+k4@#  
**Utility.java ZPHB$]ri  
*/ ><%z~s  
package NetFox; )jvYJ9s  
*?cE]U6;  
.:E%cL +h  
public class Utility { A^xD Axk  
+n7bbuxj(X  
X180_Kt2  
public Utility() ^2=11  
{ TX$j-TM'  
#Fq6-]y1")  
{eL XVNR7R  
} ;V@o 2a  
G7 b>r  
//线程睡眠 &G:#7HX@-  
public static void sleep(int nSecond) ;>bcI).  
{ EHmw(%a|+  
try{ ]F P(,:Yw  
Thread.sleep(nSecond); Enyx+]9  
} )V7bi^r  
catch(Exception e) SRyAW\*LWU  
{ Zgd| J T7  
e.printStackTrace (); It&$R`k  
} mGb,oj7l  
} (V 5_q,2  
D}OvD |<-  
//日志 <7-3j{065  
public static void log(String sMsg) 4vC { G.  
{ gy0l@ 5 N  
System.err.println(sMsg); /3{jeU.k  
} .*+%-%CbP  
{94qsVxQZ  
O8qA2@,  
public static void log(int sMsg) eh`n?C  
{ /SO 4O|b  
System.err.println(sMsg); )ERmSWq/u  
} _NA[g:DZ&O  
} ye4 T2=  
%v5IR  
HJ~0_n&  
/* rE)lt0mkv  
**TestMethod.java K?`Fpg (  
*/  Em?bV(  
package NetFox; `saDeur#X  
0ZcvpR?G  
.'aW~WR  
public class TestMethod { XnR9/t  
/x\{cHAt8J  
 UDl[  
public TestMethod() ,ELbm  
{ ///xx/weblogic60b2_win.exe \iVb;7r)9:  
try{ vr/*z euA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A0JlQE&U  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); UaG })  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d.>Zn?u4L  
fileFetch.start(); :%!` R72  
} 6ZKSet8  
catch(Exception e){e.printStackTrace ();} kbu.KU+  
@M=xdZNyJ  
B*B}eXUph  
} R<]f[  
!X5n'1&  
|}$ZOwc  
public static void main(String[] args) $IUe](a{d  
{ Qx<86aKkF  
new TestMethod(); w`ebZa/j  
} NFsj ~6F#  
} !Z(3dtUy  
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