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http断点续传简单实现(java)

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/* d0,F'?.0|  
**SiteFileFetch.java +38P$Koz{r  
*/ tqC#_[~7  
package NetFox; dK$dQR#  
import java.io.*;  kS9  
import java.net.*; d7gSkna`5c  
o`Brr:  
# =3]bg  
public class SiteFileFetch extends Thread { 7[ji,.7  
xq*yZ5:5Jo  
B 1.@K}  
SiteInfoBean siteInfoBean = null; //文件信息Bean Y>~zt -  
long[] nStartPos; //开始位置 cK@K\AE  
long[] nEndPos; //结束位置 7!)%%K.z6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :M`BVZ1t  
long nFileLength; //文件长度 "VCr^'  
boolean bFirst = true; //是否第一次取文件 IGQ8-#=  
boolean bStop = false; //停止标志 0~+ k  
File tmpFile; //文件下载的临时信息 _xsYcw~)  
DataOutputStream output; //输出到文件的输出流 vBXr[XoC  
H:Le^WS  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) UGgi)  
public SiteFileFetch(SiteInfoBean bean) throws IOException t9{EO#o' k  
{ C[,-1e?  
siteInfoBean = bean; ?J-KB3Uv3  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %V/]V,w:*R  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (#`o >G(  
if(tmpFile.exists ()) YT8`Vz$+  
{ [i_x 1  
bFirst = false; {`55nwd  
read_nPos(); xn[di-L F  
} Xs_y!l  
else 2uEu,YC  
{ N*W.V,6yH  
nStartPos = new long[bean.getNSplitter()]; AG2jl/  
nEndPos = new long[bean.getNSplitter()]; c5pG?jr+d  
} e)7r  
x N)Ck76  
.m51/X&*n  
(#lS?+w)  
} $!w%=  
fOAb?:D  
" Xc=<rX  
public void run() +=4b5*+qG  
{ SF7 Scd  
//获得文件长度 "Q4{6FH+mB  
//分割文件 \PJ89u0  
//实例FileSplitterFetch {lJpcS  
//启动FileSplitterFetch线程 } d6^  
//等待子线程返回 471}'3  
try{ X.qKG0i  
if(bFirst) p10->BBg  
{ 4LLCb7/5lP  
nFileLength = getFileSize(); pDQ,v"  
if(nFileLength == -1) g=Jfp$*[  
{ &baY[[N  
System.err.println("File Length is not known!"); s]UeDZ <a  
} P])O\<)J  
else if(nFileLength == -2) K~R{q+  
{ C/G[B?:h  
System.err.println("File is not access!"); j/&7L@Y  
} 7dZ!GX?\y  
else \)*qW[C$a  
{ H#K|SSqY?  
for(int i=0;i<nStartPos.length;i++) ?*=Jq  
{ tTal<4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); uDR(^T{g#  
} L\I/2aiE  
for(int i=0;i<nEndPos.length-1;i++) ~MF. M8  
{ _nUuiB>  
nEndPos = nStartPos[i+1]; (X/JXu{  
} "^`AS"z'  
nEndPos[nEndPos.length-1] = nFileLength; qS>el3G  
} A\>qoR!Y  
} R}FN6cH  
X*@S j;|m  
1|--Xnv  
//启动子线程 sKtH4d5)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; tEl_A"^e  
for(int i=0;i<nStartPos.length;i++) }<p%PyM  
{ I]58;|J  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %O k.XBS)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vHmn)d1pl  
nStartPos,nEndPos,i); b.(^CYYQ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7JbrIdDl|  
fileSplitterFetch.start(); #%~wuCn<K  
} u}$3.]-.?T  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kmwFw>#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $v,_8{ !  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xp = ]J UQ  
nEndPos = " + nFileLength); n7vi@^lf(  
// fileSplitterFetch[nPos.length-1].start(); hdzaU&w  
p6p_B   
h1$,  
//等待子线程结束 pB`<4+"9  
//int count = 0; *P>F# ~X  
//是否结束while循环 u56cT/J1  
boolean breakWhile = false; c{[WOrA~#  
K2JS2Y]  
H|]Q;,C  
while(!bStop) x\WKsc  
{ ``{xm1GK  
write_nPos(); GI/o!0"_  
Utility.sleep(500); 70@:!HI]  
breakWhile = true; bA:abO  
SX#ATf6#  
wXe.zLQ  
for(int i=0;i<nStartPos.length;i++) CKK8 o9W  
{ 1QThAFN  
if(!fileSplitterFetch.bDownOver) = >9`qcNW_  
{ {8eNQ-4I  
breakWhile = false; _:J! |'  
break; }QK-@T@4<  
} o 0B`~7(  
} B4%W,F:@  
if(breakWhile) \RJ428sxn  
break; "\30YO>\  
[1Rs~T"  
:0/I2:  
//count++; ~~&M&Fe  
//if(count>4) &0'BCT  
// siteStop(); 0=NB[eG  
} c(:GsoO  
d4/ZOj+%  
#-{4F?DA]y  
System.err.println("文件下载结束!"); b$hQB090  
} 'Q# KjY  
catch(Exception e){e.printStackTrace ();} ].eGsh2  
} V<b"jCXI  
>5\rU[H>  
j:g/[_0s  
//获得文件长度 tq{ aa  
public long getFileSize() rc"yEI-``"  
{ /J^yOR9  
int nFileLength = -1; O3S_P]{*ny  
try{ yA~W|q(/V  
URL url = new URL(siteInfoBean.getSSiteURL()); N7XRk= J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y:O%xtGi  
httpConnection.setRequestProperty("User-Agent","NetFox"); g94NU X  
Y`%:hvy~  
YkTEAI|i  
int responseCode=httpConnection.getResponseCode(); _95V"h  
if(responseCode>=400) /IODRso/!  
{ Xcb\N  
processErrorCode(responseCode); {C [7V{4(%  
return -2; //-2 represent access is error YQ&Xd/z-  
} fU,sn5zZ  
KdUmetx1  
bx1'  
String sHeader; DEIn:d  
#8cY,%<S]  
,`K'qms  
for(int i=1;;i++) OX!9T.j  
{ QM OOJA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n(&6 E3ZcI  
//Utility.log(in.readLine()); ;sDFTKf  
sHeader=httpConnection.getHeaderFieldKey(i); Pl U!-7  
if(sHeader!=null) I_4'9  
{ P'[w9'B  
if(sHeader.equals("Content-Length")) P7Kp*He)  
{ Eg>MG87  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7^=O^!sa  
break; 0EOpK%{  
} bPWIf*3#  
} -[Q%Vv!8  
else &q>=6sQvf  
break; 3eD#[jkAI;  
} rk `x81  
} B+ +:7!  
catch(IOException e){e.printStackTrace ();} .Gw;]s3  
catch(Exception e){e.printStackTrace ();} 't]=ps  
D3$}S{Yw1  
El ,p}Bi.  
Utility.log(nFileLength); \xwE4K  
+c?1\{M   
kP3'BBd,  
return nFileLength; [/xw5rO%  
} Iq MXd K|  
to2dkU  
G}d@^9FkE  
//保存下载信息(文件指针位置) R["_Mff  
private void write_nPos() s#>Bwn&b)  
{ j*xxOwf  
try{ {x  s{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); k1W q$KCwG  
output.writeInt(nStartPos.length); iXeywO2nP  
for(int i=0;i<nStartPos.length;i++) 0@vSl%I+  
{ r!'\$(m E  
// output.writeLong(nPos); [;%qxAB/_  
output.writeLong(fileSplitterFetch.nStartPos); 1t6VS 3  
output.writeLong(fileSplitterFetch.nEndPos); 5\lOZYHX  
} mJp)nF8r~  
output.close(); H1]G<N3  
} &Nl:  
catch(IOException e){e.printStackTrace ();} (bY#!16C:  
catch(Exception e){e.printStackTrace ();} 7EO/T,{a  
} s%GhjWZS  
?"\X46Gz;  
$ba3dqbCW  
//读取保存的下载信息(文件指针位置) 1jO}{U  
private void read_nPos() 6"b =aPTi  
{ @Pb!:HeJE  
try{ U:"E:Bxz;m  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); f 0D9Mp  
int nCount = input.readInt(); _ 7X0  
nStartPos = new long[nCount]; [kaj8  
nEndPos = new long[nCount]; r$<[`L+6  
for(int i=0;i<nStartPos.length;i++) %i:Sf  
{ 8SR~{  
nStartPos = input.readLong(); r&U5w^p  
nEndPos = input.readLong(); F6`$5%$M;?  
} 8K=sx @l  
input.close(); l@Uo4b^4x  
} Ep)rEq6  
catch(IOException e){e.printStackTrace ();} $n.oY5=\  
catch(Exception e){e.printStackTrace ();} XDRw![H,~  
} M:YtW5{  
Z(k7&^d  
)OpB\k  
private void processErrorCode(int nErrorCode) NBU[>P  
{ \$LrL  
System.err.println("Error Code : " + nErrorCode); 80DcM9^t8  
} S2T~7-  
!36jtKdM  
gTa6%GM>  
//停止文件下载 =^#^Mq)  
public void siteStop() FwKT_XkY  
{ {N!Xp:(<7_  
bStop = true; ?VaWOwWI  
for(int i=0;i<nStartPos.length;i++) lky{<jZ%  
fileSplitterFetch.splitterStop(); K =nW|^  
V~([{  
N{w)}me[YY  
} wC{?@ h  
} MZ]#9/  
//负责部分文件的抓取 SkU'JM7<95  
**FileSplitterFetch.java G;Jqby8d  
*/ ]#x!mZ!  
package NetFox; b+7!$  
Y=94<e[f"  
SFP%UfM<  
import java.io.*; V 3?x_pp  
import java.net.*; L Vt{`   
D; i%J  
T$)N2]FE  
public class FileSplitterFetch extends Thread { X} <p|P+  
>,;, 6|S  
F-0|&0  
String sURL; //File URL `_M*2(rt  
long nStartPos; //File Snippet Start Position W{'RR.  
long nEndPos; //File Snippet End Position !0p_s;uu,W  
int nThreadID; //Thread's ID [ed6n@/O@  
boolean bDownOver = false; //Downing is over %+0 7>/  
boolean bStop = false; //Stop identical 9 8O0M#|d  
FileAccessI fileAccessI = null; //File Access interface ]w*w@:Zk  
t{A/Lq9AM  
gK7bP'S8H  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException St 4YNS.|  
{ yCC.j%@  
this.sURL = sURL; u6tD5Y  
this.nStartPos = nStart; !5FZxmUup  
this.nEndPos = nEnd; ;]/>n:[ E  
nThreadID = id; g<d#zzP"T  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 A|Z'\D0  
} oVDqX=G  
u^5X@ .  
98"/]ERJ  
public void run() [R-&5 G!x  
{ GO3F[ l  
while(nStartPos < nEndPos && !bStop) dB`3"aSN7  
{ Pi7IBz  
E6 glR  
-`knSR  
try{ `GGACH3#s  
URL url = new URL(sURL); k(As^'>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1"7Rs}l7  
httpConnection.setRequestProperty("User-Agent","NetFox"); e&*< "WN  
String sProperty = "bytes="+nStartPos+"-"; T;{M9W+  
httpConnection.setRequestProperty("RANGE",sProperty); rwYlg:  
Utility.log(sProperty); sA!,)'6  
>M1m(u84#  
kta`[%KmIZ  
InputStream input = httpConnection.getInputStream(); t>]wWYy  
//logResponseHead(httpConnection); ~_|OGp_a  
~ 8hAmM  
;ndsq[k>  
byte[] b = new byte[1024]; <Vu/6"DP  
int nRead; z^xrB$8 u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <]9%Pm#X  
{ =~7%R.U([e  
nStartPos += fileAccessI.write(b,0,nRead); Jng,:$sZ  
//if(nThreadID == 1) ctqXzM `  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _hK83s4  
} 5 *w a  
qQz f&"  
"otks\I<  
Utility.log("Thread " + nThreadID + " is over!"); {Vg8pt  
bDownOver = true; gtizgUS7  
//nPos = fileAccessI.write (b,0,nRead); iPnu *29  
} f[}N  
catch(Exception e){e.printStackTrace ();} n4* hQi+d  
} \(m_3 H  
} y}TiN!M  
{i}z|'!  
kZ^}  
//打印回应的头信息 g8I=s7cnb  
public void logResponseHead(HttpURLConnection con) y:\ ^[y IQ  
{ zQ[g*  
for(int i=1;;i++) )qi/>GR,  
{ !%pY)69gv  
String header=con.getHeaderFieldKey(i); +s(JutC  
if(header!=null) 4s{_(gy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y]z^e\qc)  
Utility.log(header+" : "+con.getHeaderField(header)); aqa%B  
else lz=DP:/&  
break; &PfCY{_  
} z?a<&`W  
} 0H|U9  
ve#*qz Y  
lP9XqQ(  
public void splitterStop() iymOq9  
{ W`$D*X0*o  
bStop = true; |(mr&7O  
} -]!m4xvK  
v7;zce/~  
,}9G|$  
} *)PCPYB^  
(6Ssk4  
%j '_I\  
/* >,ThIwRN  
**FileAccess.java +@:$7m(V  
*//文件访问(定位,写) #1>DV@^F  
package NetFox; .iDxq8l  
import java.io.*; vSu|!Xb]  
 pt`^4}  
uyd y[n\  
public class FileAccessI implements Serializable{ 2(s+?n.N  
IV"OzQONx  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^>?E1J3u  
RandomAccessFile oSavedFile; s|/m}n  
long nPos; sk0N=5SB-  
D/T& 0  
mY}_9rTn|  
public FileAccessI() throws IOException +Xb )bfN  
{ dMcCSwYh  
this("",0); bzI!;P1&  
} zvvF 9  
3 #fOrNU2  
 zw13Tu  
public FileAccessI(String sName,long nPos) throws IOException jGM+  
{ \,U#^Vr  
oSavedFile = new RandomAccessFile(sName,"rw"); f?-=&||f78  
this.nPos = nPos; P>*g'OK^!G  
oSavedFile.seek(nPos); lkj^<%N"r  
} Q}a, f75  
\ 2cI=Qf  
RoL5uha,l  
public synchronized int write(byte[] b,int nStart,int nLen) M"q]jeaM  
{ =44hI86  
int n = -1; vcsrI8+  
try{ xB&kxW.;  
oSavedFile.write(b,nStart,nLen); H9c  
n = nLen; }~8/a3  
} A578g  
catch(IOException e) c&A;0**K,  
{ --ED]S 8  
e.printStackTrace (); 5&&6e`  
} $O n  
/}_OCuJJ,  
-jBk  
return n; fS( )F*J  
} ?, dbrQ  
@;T>*_Yhn  
RVlAWw(  
} |FF"vRi8a7  
Z*/*P4\  
f87> ul!*  
/* 'rT@r:6fn  
**SiteInfoBean.java c*O{?b  
*/ c1v,5c6d j  
package NetFox; 1|_8+)i;  
Dv7/eRt  
s_(%1/{  
public class SiteInfoBean { uYh6q1@"~  
gk%8iT  
8,E#vQ55}(  
private String sSiteURL; //Site's URL d+9T}? T:*  
private String sFilePath; //Saved File's Path ,zCrix 3  
private String sFileName; //Saved File's Name u )'l|Y  
private int nSplitter; //Count of Splited Downloading File P #_8$#G3  
njz:7]>e  
Tk9/1C{8  
public SiteInfoBean() M4;A4V=W  
{//nSplitter的缺省值为5 z0@)@4z!  
//default value of nSplitter is 5 In-W,   
this("","","",5); V;b^b5yZ>  
} _g%Wx?K9  
ELx?ph-9  
m?Gb5=qo  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) A+JM* eB  
{ MoKGnb  
sSiteURL= sURL; G4!$48  
sFilePath = sPath; $EHnlaG8r  
sFileName = sName; yIS.'mK  
this.nSplitter = nSpiltter; ;l]OmcL  
|+?ABPk"  
=y3gnb6  
} w|6;Pf~1y)  
0:W*_w0Ge  
d|,,,+fS  
public String getSSiteURL() :#M(,S"Qq  
{ UX-l`ygl  
return sSiteURL; 8]DN]\\o  
} mp_(ke  
|"[[.Adw9"  
By3/vb)M5  
public void setSSiteURL(String value) 5 =Os sAr  
{ Zi+>#kDV  
sSiteURL = value; ~I0I#_$'P  
}  b;!oPT  
st;.Po[h  
Fm\ h883\  
public String getSFilePath() .uAO k0^z  
{ NN<kO#c+2  
return sFilePath; t7VXW{3  
} N=) E$h  
@@U'I^iG  
>\Qyg>Md]  
public void setSFilePath(String value) WMB~? EDhv  
{ JwzA'[tM  
sFilePath = value; "RuH"~o  
} tS2P|fl  
]xf lfZ  
7y",%WYSD  
public String getSFileName() xg~ Baun  
{ MSPzOJQPy  
return sFileName; K5x&:z  
} #]G$o?@Y=^  
ziuhS4k  
H'uRgBjWJ  
public void setSFileName(String value) 2?LZW14$d  
{ ArBgg[i  
sFileName = value; \h6_m)*H4  
} e_6@oh2s-  
U8?%Dq%i  
W,zlR5+Jk  
public int getNSplitter() Or&TGwo I  
{ EP#3+B sH  
return nSplitter; OQ<|Xd I$  
} $CaF"5}?Ke  
6MfjB@  
;4nz'9+  
public void setNSplitter(int nCount)  EthnI7Y  
{ zosJ=$L  
nSplitter = nCount; *Yk3y-   
} w{[OtGIi3  
} pCSR^ua>  
EEQW$W1@  
/}?"O~5M"  
/* R1'bB"$  
**Utility.java ]}/LNO*L"  
*/ ;o;P2}zD  
package NetFox; Mn(:qQo^&`  
brN:Ypf-e  
4LYeacL B  
public class Utility { iARIvhfdi  
pg69mKZ$  
Qcu1&t\C  
public Utility() P@ '<OI  
{ RE]u2R6Y  
,.u7([SGm  
s OD>mc#%Y  
} _yT Gv-  
 \p"`!n  
//线程睡眠 b_*Y5"(*  
public static void sleep(int nSecond) e:IUO1#  
{ =!_e(J  
try{ lz X0B&:  
Thread.sleep(nSecond); f>nj9a5  
} [3++Q-rR=  
catch(Exception e) ZK))91;v  
{ wmFI?   
e.printStackTrace (); #5)E4"m  
} "Ko ^m(`  
} bH+p5Fd;  
> TG:}H(J  
//日志 HT/zcd)}#  
public static void log(String sMsg) ,Z*?"d  
{ f.0~HnNg1  
System.err.println(sMsg); mM"!=' z  
} xZt]s3?  
tWVbD%u^  
g W'aK>*c  
public static void log(int sMsg) ;X6FhQ;{*0  
{ I,D24W4l  
System.err.println(sMsg); G"0YCi#I|  
} !+& "y K@J  
} \{L!hAw  
WE \912j  
D`3m%O(?  
/* {:c*-+?  
**TestMethod.java YuD2Q{  
*/ w\KO1 Ob  
package NetFox; PgAC3%M6  
YC4S,fY`  
tUl#sqN_{  
public class TestMethod { F*rU=cu  
$O,$KAC  
g@YJ#S(}  
public TestMethod() AQ 3n=Lr   
{ ///xx/weblogic60b2_win.exe zghUwW|K  
try{ aoQK.7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C5#3c yf*B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); p=jD "lq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wI\v5&X-B  
fileFetch.start(); 8C4DOz|  
} QbqEe/*$_  
catch(Exception e){e.printStackTrace ();} }X94M7+->  
 49&p~g  
|lAu6d !  
} r> 4.{\ C  
jgbUZP4J>  
,tv P"@d  
public static void main(String[] args) fk,[`n+  
{ =7ul,  
new TestMethod(); fb[f >1|  
} =ZjF5,@  
} x3O$eKy\|5  
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