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http断点续传简单实现(java)

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/* *upl*zFf0  
**SiteFileFetch.java bNR}Mk]?  
*/ @2-Eky  
package NetFox; p`-`(i=iJo  
import java.io.*; 2-i>ymoOS  
import java.net.*; CF3Z`xD  
8 ~.|^no  
OwrzD~  
public class SiteFileFetch extends Thread { ZKyK#\v<  
|D%i3@P&ZR  
r'M|mQ$s>  
SiteInfoBean siteInfoBean = null; //文件信息Bean #r; ' AG  
long[] nStartPos; //开始位置 S`TP#uzKu]  
long[] nEndPos; //结束位置 ,JyE7h2%i  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  ] L4B  
long nFileLength; //文件长度 -J4?Km  
boolean bFirst = true; //是否第一次取文件 Wq8Uq}~_g  
boolean bStop = false; //停止标志 x]lv:m\)jT  
File tmpFile; //文件下载的临时信息 EO$_]0yI;_  
DataOutputStream output; //输出到文件的输出流  B\1F  
A@#9X'C$^  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) "0Uh(9Fv  
public SiteFileFetch(SiteInfoBean bean) throws IOException r Ip84}  
{ N7k<q=r-  
siteInfoBean = bean; |U%S<X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); g PogV(V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,T?8??bZ  
if(tmpFile.exists ()) .Y[sQO~%  
{ _|rrl  
bFirst = false; 'WkDp a  
read_nPos(); 7(lR$,bE;=  
} d9h"Q  
else Ks:~Z9r}  
{ BL6t>  
nStartPos = new long[bean.getNSplitter()]; C"_f3[Z  
nEndPos = new long[bean.getNSplitter()]; t<sg8U.  
} ]0.? 1se  
Z=n# XJO15  
c%w@-n`  
U8kH'OD  
} '`$a l7D  
12v5*G[X  
He="S3XON  
public void run() @kC>+4s!  
{ {ecmOxKP}  
//获得文件长度 fRC(Yyx  
//分割文件 TDXLxoC?  
//实例FileSplitterFetch >lQ&^9EI%  
//启动FileSplitterFetch线程 h[72iVn  
//等待子线程返回 2f ]CnD0$  
try{ 8WK%g0gm  
if(bFirst) 1XQJ#J1/  
{ q/~U[.C  
nFileLength = getFileSize(); oomB/"Z  
if(nFileLength == -1) [,)yc/{*  
{ (qT_4b~  
System.err.println("File Length is not known!"); Vd^_4uqnV  
} &hWLG<IE  
else if(nFileLength == -2) :#v8K;C  
{ YUd*\_  
System.err.println("File is not access!"); Vc|r(lM  
} L8n1p5 gx3  
else  uZ][#[u  
{ ;%P$q9 *C  
for(int i=0;i<nStartPos.length;i++) tyFhp:ZB  
{ ei'=%r8~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Cr|v3Y#h'  
} 2)]C'  
for(int i=0;i<nEndPos.length-1;i++) -]"=b\Q  
{ *f|9A/*B3  
nEndPos = nStartPos[i+1]; cn#JO^8  
} x \B!0"~  
nEndPos[nEndPos.length-1] = nFileLength; `"QUA G  
} hWpn~q  
} bUbM}  
%\#s@8=2u  
&RP!9{F<  
//启动子线程 *%_:[>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +cv7]  
for(int i=0;i<nStartPos.length;i++) e:}8|e~T  
{ Icf 4OAx  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -C.x;@!k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), d&'z0]mOe  
nStartPos,nEndPos,i); +F q`I2l|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yyZH1A  
fileSplitterFetch.start(); g/,fjM_  
} 49n.Gc  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Wh[+cH"M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ao)hb4ex  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3nv7Uz  
nEndPos = " + nFileLength); mMmzi4HL  
// fileSplitterFetch[nPos.length-1].start(); [o8a(oC  
8>a/x,  
Vt{C80n&N  
//等待子线程结束 R_ J=x  
//int count = 0; Jhu<^pjs  
//是否结束while循环 @!6eRp>Z  
boolean breakWhile = false; > kOca  
BX$t |t;!m  
{V%ZOdg9  
while(!bStop) eCdx(4(\a  
{ Zzr+p.  
write_nPos(); ie+&@u  
Utility.sleep(500); hH:7  
breakWhile = true; c.jq?Q k  
\V`O-wcJ]S  
nW+rJ  
for(int i=0;i<nStartPos.length;i++) cAC2Xq  
{ Rt~Aud[  
if(!fileSplitterFetch.bDownOver) -H~g+i*J  
{ k9UmTvX  
breakWhile = false; pW O-YZ#+  
break; P$_Y:XI !  
} VA.jt}YGE  
} */xI#G,O+  
if(breakWhile) 5P{dey!  
break; \@nmM&7C!4  
B5Rmz&  
pVn 6>\xa  
//count++; I=&5mg=m  
//if(count>4) ,R0@`t1 p  
// siteStop(); 5)V]qV$   
} gVCkj!{  
q]:+0~cz  
nk9hQRP? 8  
System.err.println("文件下载结束!"); Y{Kpopst  
} DCX 4!,ZF  
catch(Exception e){e.printStackTrace ();} =O1CxsKt6  
} Mo &Ia6^  
//KTEAYyy#  
:Oo  
//获得文件长度 mn\e(WoX  
public long getFileSize() qhVDC  
{ isHa4 D0  
int nFileLength = -1; UV)[a%/SB&  
try{ ^te9f%>$l  
URL url = new URL(siteInfoBean.getSSiteURL()); l3n* b6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }aXc,;Ps  
httpConnection.setRequestProperty("User-Agent","NetFox"); KXcG;b[7n  
N-jFA8n  
gqNd@tYI  
int responseCode=httpConnection.getResponseCode(); hF+YZU]rT  
if(responseCode>=400) E5 H6&XU  
{ ;3Fgy8 T  
processErrorCode(responseCode); $y\'j5nk3  
return -2; //-2 represent access is error 00?^!';  
} 8gJ"7,}-'  
e`4OlM]  
X1:|   
String sHeader; Cst\_j  
A)040n  
s!Y>\3rMW  
for(int i=1;;i++) {#uX   
{ r$;DA<<|<c  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 56u'XMB?  
//Utility.log(in.readLine()); $ePAsJ  
sHeader=httpConnection.getHeaderFieldKey(i); z1f~:AdL  
if(sHeader!=null) 9NaC7D$,  
{ //Ioh (N  
if(sHeader.equals("Content-Length")) ^w^cYM,  
{ eL^,-3JA(]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J[L$8y:  
break; e x $d~  
} ,V)yOLApVj  
} IyOujdKa  
else =/.[&DG  
break; zi2hi9A  
} #PoUCRRC  
} #1z}~1-  
catch(IOException e){e.printStackTrace ();} :Ff1Js(Z  
catch(Exception e){e.printStackTrace ();} q{ @>2AlK  
vBj{bnl  
U;OJ.a9  
Utility.log(nFileLength); /,2Em>  
/4w&! $M-  
r&0v,WSp&S  
return nFileLength; `"I^nD^t>Y  
} M<"&$qZ$R  
\M=" R-&b  
e_g7E+6  
//保存下载信息(文件指针位置) >8t3a-/  
private void write_nPos() Wh(V?!^@5  
{ O9p8x2  
try{ `P)atQ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); oO$a4|&,  
output.writeInt(nStartPos.length); H1 n`A#6?  
for(int i=0;i<nStartPos.length;i++) AmRppbj/wO  
{ 1A< O Z>  
// output.writeLong(nPos); `DC)U1  
output.writeLong(fileSplitterFetch.nStartPos); Jmf&&)p  
output.writeLong(fileSplitterFetch.nEndPos); A"I:cw"KY  
} @4T+0&OI10  
output.close(); $}aLFb  
} wR@fB  
catch(IOException e){e.printStackTrace ();} n_)d4d zl  
catch(Exception e){e.printStackTrace ();} Ts|&_|  
} i~ n>dc YW  
]|Vm*zO  
p/cVQ  
//读取保存的下载信息(文件指针位置) QlSZr[^v  
private void read_nPos() :I+%v  
{ 9@Cqg5Kx'  
try{ FoInJ(PDH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -_%n\#  
int nCount = input.readInt(); B+*F?k[  
nStartPos = new long[nCount]; F4e<=R  
nEndPos = new long[nCount]; :?U1^!$$1  
for(int i=0;i<nStartPos.length;i++) Sl   
{ )`,3/i9C$  
nStartPos = input.readLong(); z./u;/:  
nEndPos = input.readLong(); (YGJw?]  
} 71@V|$Dy  
input.close(); X@\rg}kP  
} )C<c{mjk(  
catch(IOException e){e.printStackTrace ();} L@ql)Lc);  
catch(Exception e){e.printStackTrace ();} n3g3(} Q0  
} RoJ{ ou@cs  
0V}%'Ec<e  
4@4$kro  
private void processErrorCode(int nErrorCode) 2Af1-z^^K  
{ cIw)ScY  
System.err.println("Error Code : " + nErrorCode); R}#?A%,*  
} H8mmmt6g  
wZ0$ylEX  
TC<_I0jCh  
//停止文件下载 "/(J*)%{  
public void siteStop() KaauX m  
{ ,&Gn7[<  
bStop = true; (caxl^=  
for(int i=0;i<nStartPos.length;i++) bsmZR(EnU  
fileSplitterFetch.splitterStop(); Vge9AH:op  
O< v0{z09*  
#B88w9 b`D  
} %S. _3`A  
} MQG(n+c  
//负责部分文件的抓取 .Qyq*6T3&  
**FileSplitterFetch.java G yvEc3|@  
*/ 7s4G|N[wR\  
package NetFox; d!D#:l3;  
0/6f9A  
K pDKIi  
import java.io.*; ey_3ah3x  
import java.net.*; 5*/~) wN\U  
$>hPB[[  
Y^M3m' d?  
public class FileSplitterFetch extends Thread { [o<Rgq 4  
etMQy6E\  
B36_ OH  
String sURL; //File URL CCNrjaA  
long nStartPos; //File Snippet Start Position p`fUpARA!  
long nEndPos; //File Snippet End Position j_H9l,V  
int nThreadID; //Thread's ID W;4rhZEgd  
boolean bDownOver = false; //Downing is over M2W4 RovfR  
boolean bStop = false; //Stop identical Sb+^~M  
FileAccessI fileAccessI = null; //File Access interface i+ ]3J/J  
ZP &q7HK\  
)"/.2S;  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s/"&k  
{ $M5iU@A  
this.sURL = sURL; J: vq)G\F  
this.nStartPos = nStart; { 0RwjPYp  
this.nEndPos = nEnd; ,bzE`6  
nThreadID = id; e{EKM4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Q'5]E{1<'n  
} ^hr^f;N  
"Rr)1x7  
-+?ZJ^A   
public void run() T1%_sq  
{ Rsd~t_a1  
while(nStartPos < nEndPos && !bStop) ,P ~jO  
{ 1Bp?HyCR  
:%7y6V*  
@rI+.X  
try{ !k@ (}CN_*  
URL url = new URL(sURL); 5,  "  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >!sxX = <  
httpConnection.setRequestProperty("User-Agent","NetFox"); o5LyBUJ  
String sProperty = "bytes="+nStartPos+"-"; =hFIH\x  
httpConnection.setRequestProperty("RANGE",sProperty); 7IkNS  
Utility.log(sProperty); 3w!8PPl  
lt08 E2p9  
xKl\:}Ytp  
InputStream input = httpConnection.getInputStream(); ^x2zMB\t  
//logResponseHead(httpConnection); K93L-K^J  
Cq8.^=}_  
X!,huB^i  
byte[] b = new byte[1024]; FxU a5 n  
int nRead; j/ [V<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) rf?%- X(V  
{ AS4mJ UU9  
nStartPos += fileAccessI.write(b,0,nRead); Q~k5 }n8  
//if(nThreadID == 1) ":@\kw  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); | KtI:n4d  
} B']-4X{SGa  
UOIB}ut V  
>PuQ{T I  
Utility.log("Thread " + nThreadID + " is over!"); J4?i\wD:  
bDownOver = true; boS=  
//nPos = fileAccessI.write (b,0,nRead); w1Txz4JqB  
} 6 &Lr/J76  
catch(Exception e){e.printStackTrace ();} @cB7tY*Ski  
} 0:I[;Q t  
} AjVX  
_=Z?5{7S >  
:A7\eN5  
//打印回应的头信息 =xw+cs1,x  
public void logResponseHead(HttpURLConnection con) %lq[,6?>5  
{ -\<\OV:c*  
for(int i=1;;i++) 9U>OeTh(  
{ .Ht;xq  
String header=con.getHeaderFieldKey(i); "UX/yLc3(  
if(header!=null) 7F2 WmMS  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +Jm~Um!  
Utility.log(header+" : "+con.getHeaderField(header)); 1-V"uLy@gC  
else -w"$[XP  
break; s Poh\n  
} : &bJMzB  
} BItH0r7  
5G2G<[p5oQ  
:6MV@{;PJ  
public void splitterStop() 6l'J!4*qY  
{ 3{)!T;Wd  
bStop = true; =MU(!`  
} OxQ5P;O  
&@K6;T  
d.|*sZ&3p  
} 9(3]t}J5 d  
sZI"2[bk  
7KesfH?  
/* QJ&]4*>a  
**FileAccess.java q68CU~i*  
*//文件访问(定位,写) E.%V 0}  
package NetFox; Lk)I;;  
import java.io.*; 0!-'4+"  
5tyA{&Ao  
3! #|hI>f  
public class FileAccessI implements Serializable{ up{0ehr  
o}DR p4;Ka  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4> uNH5  
RandomAccessFile oSavedFile; T+^Sa J  
long nPos; [>N#61CV 5  
ht*N[Pi4;  
idB1%?<  
public FileAccessI() throws IOException @0]w!q  
{ ~/X8Hy!-  
this("",0); Ni8%K6]z  
} udT0`6l;  
_CPj] m{  
@ <3E `j'p  
public FileAccessI(String sName,long nPos) throws IOException Mq#m;v$E  
{ '<3h8\"  
oSavedFile = new RandomAccessFile(sName,"rw"); j85B{Mab&  
this.nPos = nPos; w[F})u]E  
oSavedFile.seek(nPos); ]isq}Qv~  
} s >:gL,%c  
\s%g'g;  
l9C `:g  
public synchronized int write(byte[] b,int nStart,int nLen) k,$/l1D  
{ Rz&`L8Bz  
int n = -1; %X's/;(Lx`  
try{ g4=C]\1  
oSavedFile.write(b,nStart,nLen); 0J^Z)U>j  
n = nLen; Dt<MEpbur  
} A +=#  
catch(IOException e) 9+MW13?  
{ c]Gs{V]\  
e.printStackTrace (); %19~9Tw  
} !yT=*Cj4  
_p0gXb1m`  
tvf5b8(Y-  
return n; b1>]?.  
} B8eZ}9X  
V,rR*a&p  
P>u2""c  
} p+<qI~  
w>\oz  
,"5HJA4  
/* ,tQN L\t  
**SiteInfoBean.java Go1xyd:k  
*/ utRO?]%d !  
package NetFox; 50dN~(;p  
J~xm[^0  
@{#'y4\>  
public class SiteInfoBean { kssRwe%>;  
@67GVPcxl  
q+4dHS)x  
private String sSiteURL; //Site's URL *Gv:N6  
private String sFilePath; //Saved File's Path X.>~DT%0Lm  
private String sFileName; //Saved File's Name % >a /m.$  
private int nSplitter; //Count of Splited Downloading File 8 e_]  
ern\QAhXX  
+|b#|>6  
public SiteInfoBean() JL!^R_b&c  
{//nSplitter的缺省值为5 ~:k r;n2  
//default value of nSplitter is 5 ^wc:qll  
this("","","",5); shL_{}  
} o/ 51 RH  
@YRy)+  
k&:q|[N  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w8~R=k  
{ bf=\ED^  
sSiteURL= sURL; #g@4c3um|  
sFilePath = sPath; $<XQv$YS  
sFileName = sName; ?./fVoA]V  
this.nSplitter = nSpiltter; o\ce|Dzt  
h8%QF'C  
%scIZCrI~  
} A@?-"=h}  
!5h-$;  
Ac{TqiIv  
public String getSSiteURL() ~|, "w90  
{ *Q?8OwhJ  
return sSiteURL; Pzd!"Gl9  
} oiR9NB&<  
"[k>pzl6  
5M9o(Z\AF  
public void setSSiteURL(String value) ]8OmYU%6V  
{ D3,)H%5.y  
sSiteURL = value; 6< -Cpc  
} Il>o60u1  
gBWr)R  
/qwY/^  
public String getSFilePath() ar 7.O;e  
{ AB0}6g^O  
return sFilePath; TG8U=9qt  
} vg3iT }  
jA2%kX\6//  
pRxVsOb  
public void setSFilePath(String value) D-t!{LA  
{ i"Hc(lg  
sFilePath = value; ToKG;Ff4b  
} K0o${%'@7  
Ktt(l-e+  
x $[_Hix  
public String getSFileName() &}C-W* f,Z  
{ dblf , x  
return sFileName; DnhbMxh8o  
} E@)'Z6r1  
-$#2?/uqC  
U|.r -$|5P  
public void setSFileName(String value) )K::WqR%w)  
{ nQ|($V1?W  
sFileName = value; (E,[Ad,$  
} 1^GRUbOU[  
l O*  
[4bE"u  
public int getNSplitter() S= `$w  
{ 3m4 sh~  
return nSplitter; snu?+*6  
} 5A 5t  
Btr>ek  
8KkN "4'  
public void setNSplitter(int nCount) _*{Lha  
{ U7g,@/Qx  
nSplitter = nCount; 3fX _XH1Q  
} IZ^:wIKo{  
} a+O?bO  
1=9GV+`n  
(|<+yQ,@>  
/* car|&b  
**Utility.java >o`+j$j  
*/ #4"eQ*.*"  
package NetFox; Uugq.'>  
UmMu|`  
Ku uiU= (L  
public class Utility { 8:*ZuR|~  
kSCpr0c  
Zy?!;`c*{  
public Utility() :9x]5;ma  
{ -byaV;T?"  
FjiIB1 T  
7i02M~*uS  
} S5Pn6'w  
hcYqiM@8>  
//线程睡眠 +;pw^QB  
public static void sleep(int nSecond) Lc]hwMGR*  
{ w~pe?j_F$  
try{ QGGBI Ku   
Thread.sleep(nSecond); U#w0E G  
} iYw1{U  
catch(Exception e) ]-a/)8  
{ n+<  
e.printStackTrace (); Nr)DU.f  
} MU `!s b*  
} ER[$TH&  
60e{]}Z  
//日志 x5;D'Y t"|  
public static void log(String sMsg) 5 /oW/2"  
{ M _cm,|FF  
System.err.println(sMsg); /!6 VP |  
} nG?Z* n  
l>BM}hS  
~+Cl9:4T  
public static void log(int sMsg) @(N} {om  
{ 4&e<Sc64  
System.err.println(sMsg); };Df ><  
} I.~=\%Z {  
} 0lOan  
6e5A8e8"]  
_Vt9ckaA  
/* oz|+{b}%  
**TestMethod.java i/!KUbt  
*/ Q4S:/"*v8  
package NetFox; [x`),3qD  
*] >R  
k{|> !(Ax  
public class TestMethod { pRsIi_~&  
-sDl[  
~qTChCXP  
public TestMethod() NQiu>Sg  
{ ///xx/weblogic60b2_win.exe KRP6b:+4L  
try{ &Akw V-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); I?\P^f  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); g@?R"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wk^$DM/KJ)  
fileFetch.start(); '*&V7:  
} W!=ur,F+  
catch(Exception e){e.printStackTrace ();} |GPY bxzc  
c0X1})q$  
SF ^$p$mC  
} Pe11a zJ  
zpNt[F?~1  
GQjU="+  
public static void main(String[] args) *8u<?~9F  
{ LJ z6)kz  
new TestMethod(); \t&8J+%  
} kaECjZ _&+  
} {8%KO1xB  
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