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http断点续传简单实现(java)

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/* zu Jl #3YP  
**SiteFileFetch.java %Pb 5PIk4  
*/ _,M:"3;Z  
package NetFox; #j{!&4M  
import java.io.*; L('G1J}  
import java.net.*; ,~_)Cf#CB  
F+@E6I'g  
G;%Pf9 o26  
public class SiteFileFetch extends Thread { 6T_Mk0Sf+  
l&d 6G0  
g(0 |p6R  
SiteInfoBean siteInfoBean = null; //文件信息Bean O} !L;?  
long[] nStartPos; //开始位置 =*YK6  
long[] nEndPos; //结束位置 K"sfN~@rT[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 KR6*)?c`  
long nFileLength; //文件长度 hC.7Z]  
boolean bFirst = true; //是否第一次取文件 <E|K<}W#  
boolean bStop = false; //停止标志 bTn7$EG  
File tmpFile; //文件下载的临时信息 L:y} L  
DataOutputStream output; //输出到文件的输出流 _r}oYs%1  
)oSUhU26}  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 3 9Ql|l$  
public SiteFileFetch(SiteInfoBean bean) throws IOException t?0D*!D  
{ rwlV\BU  
siteInfoBean = bean; {t$ vsR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Odr@9MJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ul e]eRAG  
if(tmpFile.exists ()) :I5]|pt  
{ "b!QE2bRO  
bFirst = false; ogX'3L  
read_nPos(); 4><b3r;T'  
} )CzWq}:  
else PomX@N}1  
{ 6?0 ^U 9  
nStartPos = new long[bean.getNSplitter()]; K'%,dn  
nEndPos = new long[bean.getNSplitter()]; ~7!J/LHg  
} %3i/PIN  
.6[xX?i^T  
g]V}azLr  
1@Bq-2OD4  
} dyjzF`H  
W&]grG2/  
W9?Yzl  
public void run() <4y1[/S  
{ -0Q:0wU  
//获得文件长度 NBR6$n  
//分割文件 \>j._#t$h  
//实例FileSplitterFetch TD-d5P^Kek  
//启动FileSplitterFetch线程 !b*lL#s,Y  
//等待子线程返回 vL13~q*F  
try{ }}?L'Vby  
if(bFirst) OxqbHe  
{ :YB:)wV,P  
nFileLength = getFileSize(); ML0o :8Bd\  
if(nFileLength == -1) Etj*3/n|  
{ A^JeB<, 5a  
System.err.println("File Length is not known!"); <>f  
} 2C %{A  
else if(nFileLength == -2) f{lg{gA(  
{ LS?hb)7  
System.err.println("File is not access!"); 2|o6~m<pE  
} Um\Nd#=:  
else GljxYH"]#  
{ kF~}htv.=  
for(int i=0;i<nStartPos.length;i++) qyc:;3?wm  
{ GD|uU  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )vsiX}3  
} @.-g  
for(int i=0;i<nEndPos.length-1;i++) ,:-S<]fS{_  
{ ;tI=xNre`1  
nEndPos = nStartPos[i+1]; FpfOxF6A3  
} !xMyk>%2  
nEndPos[nEndPos.length-1] = nFileLength; Nm<3bd  
} Rcf_31 L  
} W k'()N  
K2L+tw  
T"t3e=xA  
//启动子线程 +J$[RxQ#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; '@HWp8+  
for(int i=0;i<nStartPos.length;i++) s_K:h  
{ [e ;K$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SMgf(N3]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), XN]kNJX  
nStartPos,nEndPos,i); :SSe0ZZ_6b  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J']1^"_'  
fileSplitterFetch.start(); &oYX093di  
} p0uQ>[NV0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0<Px 2/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @g""*T1:$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Gy 'l;2  
nEndPos = " + nFileLength); 1c,$D5#  
// fileSplitterFetch[nPos.length-1].start(); ,g{`M]Ov  
8:-[wl/@  
J}KATpHs  
//等待子线程结束 @y9_\mX!s  
//int count = 0; E<'3?(D9hL  
//是否结束while循环 /l0\SVwa>  
boolean breakWhile = false; a)4.[+wnRf  
bWwc2##7jo  
i+jSXn"_  
while(!bStop)  F[115/  
{ ;hmy7M1%  
write_nPos(); ?bQ~ +M\  
Utility.sleep(500); Az6f I*yP  
breakWhile = true; =4/lJm``  
I9ubVcV8  
>!wX% QHH  
for(int i=0;i<nStartPos.length;i++) &K)c*' l  
{ {Rjj  
if(!fileSplitterFetch.bDownOver) [1dlV/  
{ RMmDcvM"k  
breakWhile = false; # o)a`,f  
break; N4}/n  
} Z|uUE   
} >I8R[@  
if(breakWhile) 5>"$95D  
break; a~7`;Ar  
S!2M?}LU  
[$]vi`c2  
//count++; nod?v2%   
//if(count>4) -O\!IXG^  
// siteStop();  _*9eAeJ  
} XJC|6"n  
%IW=[D6Tg  
&voyEvX/S  
System.err.println("文件下载结束!"); wvcG <sj  
} 3uz@JY"mK  
catch(Exception e){e.printStackTrace ();} !V$m!i;  
} 3rTYe6q$U  
-2w\8]u  
4At%{E  
//获得文件长度 Obrv5 %'  
public long getFileSize() V3xC"maA@  
{ gx#xB8n  
int nFileLength = -1; c@~\ FUr  
try{ 7z)Hq./3@  
URL url = new URL(siteInfoBean.getSSiteURL()); BE:HO^-.1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w8kp6_i'  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7\rz*  
=\ iV=1iB  
6^s=25>p  
int responseCode=httpConnection.getResponseCode(); "D2 `=D!+  
if(responseCode>=400) ,*Tf9=z  
{ .4Jea#M&x  
processErrorCode(responseCode); G  2+A`\]  
return -2; //-2 represent access is error zdzTJiY2[Z  
} ZTVX5"#Q  
4W*52*'F,  
S j)&!  
String sHeader; 0j7W\'!t  
BYyR-m  
p./zW )7+  
for(int i=1;;i++) A|I7R -  
{ T'  %TMA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |#LU"D  
//Utility.log(in.readLine()); GP<A v1  
sHeader=httpConnection.getHeaderFieldKey(i); 9sFZs]uM  
if(sHeader!=null) G}&B{Ir  
{ e]'ui<`  
if(sHeader.equals("Content-Length")) 6x^#|;e>lI  
{ (2[tQ`~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1CU-^ j  
break; r;g[<6`!S  
} "6w-jT  
} Vi?[yu<F  
else 93$'PwWgiF  
break; 1\=)b< y  
} C,P>7  
} BRPvBs?Q,{  
catch(IOException e){e.printStackTrace ();} s% 2w&Us*  
catch(Exception e){e.printStackTrace ();} IKMkpX!]  
R7r` (c!  
HJo&snT3  
Utility.log(nFileLength); :$~)i?ge<5  
Jajo!X*Wai  
"9jt2@<  
return nFileLength; aJ}y|+Cj  
} k(pI5N}pJZ  
X+z!?W*a  
3vfm$sx@  
//保存下载信息(文件指针位置) uPr'by  
private void write_nPos() 2w>WS#  
{ PTWP7A[  
try{ [fiB!G ]?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !1$Q Nxgi  
output.writeInt(nStartPos.length); /bv1R5  
for(int i=0;i<nStartPos.length;i++) Q0K2md_%x  
{ N_rz~$|@9  
// output.writeLong(nPos); ?n)d: )Ud"  
output.writeLong(fileSplitterFetch.nStartPos); RZ-=UIf  
output.writeLong(fileSplitterFetch.nEndPos); w=Ac/ 12  
} <u]M):b3  
output.close(); ?`bi8 Ck  
} N DZ :`D  
catch(IOException e){e.printStackTrace ();} 1@rI4U@D  
catch(Exception e){e.printStackTrace ();} v;AsV`g  
} }:<`L\8q\  
4$#nciAe  
tgSl (.  
//读取保存的下载信息(文件指针位置) Anr''J&9`H  
private void read_nPos() 1O]'iS"  
{ epuN~T  
try{ >?aPX C  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {AUhF}O  
int nCount = input.readInt(); mSF>~D1_  
nStartPos = new long[nCount]; VW:WB.K$  
nEndPos = new long[nCount]; &TJMopVn  
for(int i=0;i<nStartPos.length;i++) 4r&DW'  
{ e&sZ]{uD  
nStartPos = input.readLong(); meey5}  
nEndPos = input.readLong(); >-J%=P  
} _;L%? -2c  
input.close(); }Q&zYC]d  
} z*n  
catch(IOException e){e.printStackTrace ();} Yef=HSzo  
catch(Exception e){e.printStackTrace ();} (8T36pt~  
} `Sgj!/! F  
"Zm**h.t  
& mwQj<Z  
private void processErrorCode(int nErrorCode) d5Hp&tm  
{ +a1Or  
System.err.println("Error Code : " + nErrorCode); H3\4&q  
} nwuH:6~"  
eB%hP9=:x  
XrP'FLY o  
//停止文件下载 B_R J;.oH  
public void siteStop() p}H:t24Cr5  
{ vP6NIcWC3  
bStop = true; t|-TG\Q X  
for(int i=0;i<nStartPos.length;i++) t6u>_Sh e  
fileSplitterFetch.splitterStop(); ;e Iqxe>  
`o/G0~T)  
&O8vI ,M  
} riw0w  
} 7q\&  
//负责部分文件的抓取 RP[^1  
**FileSplitterFetch.java 2E5n07,  
*/ +g %h,@  
package NetFox; $d0xJxM  
WXHvUiFf  
LX f r  
import java.io.*; U}f"a!  
import java.net.*; DBTeV-G9~R  
OM,Dy&Y  
h0**[LDH  
public class FileSplitterFetch extends Thread { *rKj%Me  
<"/b 5kc  
QguRU|y  
String sURL; //File URL 7`eg;s^  
long nStartPos; //File Snippet Start Position (h {"/sR  
long nEndPos; //File Snippet End Position CCoT  
int nThreadID; //Thread's ID HGycF|]2  
boolean bDownOver = false; //Downing is over ?{=& Ro  
boolean bStop = false; //Stop identical rtM29~c>@  
FileAccessI fileAccessI = null; //File Access interface )M3} 6^s]  
xXb7/.*qE  
Ln-UN$2~F  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException M2Q*#U>6r  
{ L#huTKX}  
this.sURL = sURL; JG^fu*K  
this.nStartPos = nStart; wFbw3>'a9  
this.nEndPos = nEnd; LV}Z[\?   
nThreadID = id; ohEIr2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 F:$*0!  
} Dh+<|6mx  
z`]sWi F0  
QC\r|RXW  
public void run() #su R[K*S  
{ Z$*m=]2  
while(nStartPos < nEndPos && !bStop) ,8.Fd|#L  
{ .)(5F45Wg  
(1%O;D.*?{  
 N>V\  
try{ ,zF^^,lO7  
URL url = new URL(sURL); Cx~,wk;=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A4K8DP  
httpConnection.setRequestProperty("User-Agent","NetFox"); y26?>.!  
String sProperty = "bytes="+nStartPos+"-"; gn-@OmIs  
httpConnection.setRequestProperty("RANGE",sProperty); hl} iw_e  
Utility.log(sProperty); cQzUR^oq,  
cnw?3/J  
H8!; XB  
InputStream input = httpConnection.getInputStream(); 8kdJ;%^N  
//logResponseHead(httpConnection); 2^aXXPC  
2xxw8_~C  
i<\WRzVT  
byte[] b = new byte[1024]; #'y4UN  
int nRead; Dpb prT7_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _ASyGmO{  
{ .n\j<Kq  
nStartPos += fileAccessI.write(b,0,nRead); 6 uS;H]nd<  
//if(nThreadID == 1) ,vDSY N6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /Fj*sS8  
} 8*x/NaH /\  
\Gl>$5np  
`8 Ann~Z|k  
Utility.log("Thread " + nThreadID + " is over!"); PAD&sTjE*  
bDownOver = true; D4OJin^}  
//nPos = fileAccessI.write (b,0,nRead); 2 xE+"?0  
} 'Lu d=u{  
catch(Exception e){e.printStackTrace ();} f|+aa6hN  
} E !EENg  
} 1[] 9EJ  
QnJd}(yN  
Mg~62u  
//打印回应的头信息 V}aZ}m{J  
public void logResponseHead(HttpURLConnection con) *-eDU T|O  
{ `RlMfd  
for(int i=1;;i++) @f!r"P]  
{ ]mR!-Fqj  
String header=con.getHeaderFieldKey(i); mI> =S  
if(header!=null) t) uS7y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /1BqC3]tL  
Utility.log(header+" : "+con.getHeaderField(header)); jR[b7s  
else %n{ue9  
break; jvQpf d  
} Vi=u}(*  
} B<{Yj}..  
e;8nujdG"  
(jI_Dk;  
public void splitterStop() {Gvv^.H7  
{ IkP; i_|  
bStop = true; GMKY1{   
} dbG902dR  
G2 0   
]?*'[  
} wh2Ljskda8  
wiP )"g.t  
"'3QKeM1  
/* ' e:rL.  
**FileAccess.java $!goM~pZ  
*//文件访问(定位,写) ,a34=,  
package NetFox; "1wjh=@z  
import java.io.*; .b|!FWHNS  
q[TGEgG  
s 9n_s=w  
public class FileAccessI implements Serializable{ Pi5($cn  
m;cgX#k5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *@eZt*_  
RandomAccessFile oSavedFile; bH}?DMq]O  
long nPos; w 6  
\R[f< K%  
,1 ^IFBJ  
public FileAccessI() throws IOException K3^2;j1F Q  
{ LEd@""h  
this("",0); _ SJ Fuv/  
} G-[.BWQ   
:>-&  
7-Mm+4O9  
public FileAccessI(String sName,long nPos) throws IOException }B`T%(11=  
{ !B/5@P  
oSavedFile = new RandomAccessFile(sName,"rw"); MLvd6tIv,  
this.nPos = nPos; AhU   
oSavedFile.seek(nPos); CHckmCgf4  
} R4%}IT^%P  
3H`r|R  
gxc8O).5vY  
public synchronized int write(byte[] b,int nStart,int nLen) "ph[)/u;  
{ )v+\1  
int n = -1; ~o27~R ]  
try{ VXO.S)v2J  
oSavedFile.write(b,nStart,nLen); ]sD lZJX<M  
n = nLen; }u.I%{4  
} y_M,p?]^,  
catch(IOException e) P?|>, \t  
{ ,uL}O]L  
e.printStackTrace (); c7@[RG !  
} Y' O3RA5E  
B8 r#o=q1  
WelB"L  
return n; bL2b^UB~%  
} -Mzm~@_s]  
,In}be$:  
[j 'lB  
} (5GjtFojY|  
" +A8w  
om{aws;  
/* *6wt+twH  
**SiteInfoBean.java 5Ve T8/7Q  
*/ \# _w=gs<i  
package NetFox; AvcN,  
IoCi(N;  
| $D`*  
public class SiteInfoBean { 7g.3)1  
e=Q{CsP  
YSr u5Q  
private String sSiteURL; //Site's URL B *otqu z  
private String sFilePath; //Saved File's Path _ykT(`.#  
private String sFileName; //Saved File's Name do DpTwvh  
private int nSplitter; //Count of Splited Downloading File fl+2 '~  
Yu: !l>  
s:*" b'  
public SiteInfoBean() !"SuE)WM  
{//nSplitter的缺省值为5 Lnc>O'<5P9  
//default value of nSplitter is 5 [!YSW'  
this("","","",5); SquuK1P=  
} -d *je{c |  
<xh";seL  
78kT}kgW  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >dfk2.6e  
{ #;hYJ Y  
sSiteURL= sURL; \@$V^;OP/  
sFilePath = sPath; &5n0J  
sFileName = sName; _)MbvF  
this.nSplitter = nSpiltter; vt(cC) )  
EttQ<z_T  
; mwU>l,4  
} k? !'OHmBL  
s!?T$@a=  
lr9s`>9  
public String getSSiteURL() #T08H,W/  
{ w0,rFWS  
return sSiteURL; O"emse}Z  
} 'a=' (,%  
C%Fc%}[  
PDhoCAh !  
public void setSSiteURL(String value) I*0TI@Lo  
{ *eAzk2  
sSiteURL = value; .$-GGvN]  
} B8NMo5a  
:y^%I xs{1  
?dY|,_O  
public String getSFilePath() -GT&46hX  
{ sW0<f& 3  
return sFilePath; '\R/-.  
} i| CAN,'  
o,_R;'\E[a  
wqA7_ -  
public void setSFilePath(String value) tB<|7  
{ .iZo/_  
sFilePath = value; `Zd\d:Wyv  
} 2py [P  
}\]J?I+A  
KVp3 pUO  
public String getSFileName() Iz9b5  
{ E&>=  
return sFileName; W*9*^  
} >=d%t6 %(  
AZfW  
M{O8iq[  
public void setSFileName(String value) m!Fx#   
{ s]2_d|Y  
sFileName = value; m[D]4h9  
} {qb2!}FQ  
Kq;s${ |G  
lR0WDJv  
public int getNSplitter() O_^t u?x  
{  f~w!Z  
return nSplitter; 8'o6:  
} b9TsuY  
4{rj 4P?  
D}]u9jS1  
public void setNSplitter(int nCount) iDV. C@   
{ tVhf1TH#  
nSplitter = nCount; $kd9^lj#[  
} Q3 yW#eD  
} #L 9F\ <K  
,g:\8*Y>'  
8"C[sRhz  
/* p #Y2v  
**Utility.java fm$)?E_Rp  
*/ -gVsOX0  
package NetFox; &z?:s  
rixt_}aE  
@h!nVf%fe  
public class Utility { /7hC /!@  
5?XIp6%x  
o>Q=V 0?  
public Utility() OtZc;c  
{ i?B(I4a!G  
r"&VG2c0K  
[xHHm5$  
} XY!0yAK(!  
%IK[d#HO  
//线程睡眠 'yNS(Bg=  
public static void sleep(int nSecond) :Hq#co  
{ Ih^ziDcW  
try{ Q<T+t0G\O-  
Thread.sleep(nSecond); Uq^-km#a  
} L'r gCOJ<  
catch(Exception e) UB,:won  
{ >Qx :l#B  
e.printStackTrace (); !30BR|K*  
} T[ltOQw?Y  
} PAS0 D #  
u_jhmKr~  
//日志 .A apO}{  
public static void log(String sMsg) [(m+Ejzi%  
{ ][1 iKT  
System.err.println(sMsg); #b94S?dq  
} n 'E:uXv"  
+MyXIWmD  
>$G'=N:=X&  
public static void log(int sMsg) x`JhNAO>  
{ !dGSZ|YZ  
System.err.println(sMsg); ?<STl-]&  
} SYwB #|  
} GL'l "L  
Z~v-@  
jW;g{5X  
/* <3!Q Xc  
**TestMethod.java tO+Lf2Ni+  
*/ ].HHTCD`c  
package NetFox; D8f4X w}=  
si#1sdR  
raJv$P  
public class TestMethod { SSysOeD+  
U o[\1)  
'w?}~D.y  
public TestMethod() 5F$~ZDu  
{ ///xx/weblogic60b2_win.exe HUalD3 \  
try{ 'g:.&4x_w  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0bl8J5Ar5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D.*o^{w|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); k nljc^  
fileFetch.start(); u{5+hZ  
} xl ,(=L]  
catch(Exception e){e.printStackTrace ();} %gEgp Jd  
";;Nc>-Y  
v@Qfx V2  
} @G^m+-  
Hv-f :P O  
Dbw{E:pq  
public static void main(String[] args) +d=w%r)  
{ sw+vyBV)r  
new TestMethod(); 1.I58(0~+  
} z -uW,  
} %<{1 N|  
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