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http断点续传简单实现(java)

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/* R/Dy05nloe  
**SiteFileFetch.java /nMqEHCyg  
*/ X!M fJ^)q  
package NetFox; Xv5Ev@T  
import java.io.*; &PQ{e8w  
import java.net.*; e/HX,sf_g  
WEV{C(u<k!  
K}5 $;W#  
public class SiteFileFetch extends Thread { vu.S>2Wv  
s!o<Pd yJK  
X$9D0;L  
SiteInfoBean siteInfoBean = null; //文件信息Bean E~Up\f  
long[] nStartPos; //开始位置 aIt 0;D  
long[] nEndPos; //结束位置 Am=PUQF$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 k0 e|8g X  
long nFileLength; //文件长度 #Mem2cz  
boolean bFirst = true; //是否第一次取文件 gH{\y5%rO  
boolean bStop = false; //停止标志 [>Kxm  
File tmpFile; //文件下载的临时信息 b1>$sPJ+  
DataOutputStream output; //输出到文件的输出流 4qSS<SqY  
qYu!:xa8  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) (krG0S:0Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException RH'F<!p  
{ *(SBl}f4l  
siteInfoBean = bean; FO'. a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ZV<y=F*~f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ff#N|L'9_  
if(tmpFile.exists ()) VzYP:QRz  
{ ,YMdXYu`s  
bFirst = false; S5pP"&I[  
read_nPos(); u, SX`6%  
} 8DS5<  
else knK=ENf;e  
{ ;'18  
nStartPos = new long[bean.getNSplitter()]; (B/F6 X;o.  
nEndPos = new long[bean.getNSplitter()]; %"KWjwp  
} K[|P6J   
z#E,96R  
08jUVHdt  
lSbM)gL  
} ~z1KD)^   
U/&qV"Ih  
VQNH@g^gqr  
public void run() owY_cDzrH  
{ \7tvNa,C  
//获得文件长度 0!'M#'m  
//分割文件 7/OOq=z  
//实例FileSplitterFetch 3]]6z K^i  
//启动FileSplitterFetch线程 Z-p^3t'{  
//等待子线程返回 &$z1Hz+l  
try{ Pymh^i  
if(bFirst) k#r7&Y  
{ Y)5uK:)^  
nFileLength = getFileSize(); rnBeL _8C  
if(nFileLength == -1) 3^-)gK  
{ /G{3p&9  
System.err.println("File Length is not known!"); {)[g  
} Umwg iw  
else if(nFileLength == -2) vls> 6h  
{ [c!vsh]^  
System.err.println("File is not access!");  iIEIGQx  
} YIk6:W{  
else | v'5*n9  
{ @k #y-/~?  
for(int i=0;i<nStartPos.length;i++) oJu4vGy0  
{ r`g;k&"a  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); z4fK{S  
} ]:#$6D"  
for(int i=0;i<nEndPos.length-1;i++) wkpVX*DfRE  
{ Mc3h  R0  
nEndPos = nStartPos[i+1]; *U^I `j[u  
} d\Z4?@T<5  
nEndPos[nEndPos.length-1] = nFileLength; lR K ?%~  
} Z6AU%3]  
} L8K3&[l%  
3Co>3d_  
Cwa0!y5%  
//启动子线程 ?&nz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; L#@$Mtc  
for(int i=0;i<nStartPos.length;i++) w>UV\`x  
{ dZYJ(7%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^Jpd9KK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Oc+L^}elJ  
nStartPos,nEndPos,i); 4_:e+ ql  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); td$6:)  
fileSplitterFetch.start(); xENA:j?kF  
} ~HI0<;r=eL  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s ;Nu2aOp7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); XUNgt(OGR'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", & ~G  
nEndPos = " + nFileLength); ;B7|tajd  
// fileSplitterFetch[nPos.length-1].start(); G8-d%O p  
5e8-?w% e  
g\nL n#  
//等待子线程结束 Ae zXou&  
//int count = 0; ';!UJWYl  
//是否结束while循环 "m)O13x  
boolean breakWhile = false; \mit&EUh}  
A_ z:^9  
p 8Hv7*  
while(!bStop) Y tj>U  
{ _r)nbQm&  
write_nPos(); 4IE#dwZW  
Utility.sleep(500); W&[9x%Ba  
breakWhile = true; Jpnp'  
.@Sh,^v  
RXvcy<  
for(int i=0;i<nStartPos.length;i++) H$iMP.AK  
{ \/%Q PE8  
if(!fileSplitterFetch.bDownOver) u}0t`w:  
{ xW )8mv?4n  
breakWhile = false; `fVA. %  
break; -* j;  
} ]@]"bF!Dn  
} iv`-)UsE  
if(breakWhile) sJYX[  
break; jo:p*Q "F  
~;a* Oxt  
?UIb!k>  
//count++; NPq2C8:  
//if(count>4) oYm"NDS_.  
// siteStop(); hrxASAfg6  
} iU|C<A%Hh  
Ek\Zi#f<  
w5R9\<3L  
System.err.println("文件下载结束!"); YWd(xm"4  
} kQcQi}e  
catch(Exception e){e.printStackTrace ();} fP*C*4#X  
} j+v)I=  
X,Q(W0-6$u  
j}Mpc;XOc  
//获得文件长度 M/ \~  
public long getFileSize() BNLall  
{ SK2pOZN  
int nFileLength = -1; #Z5~a9rO  
try{ "lMWSCas  
URL url = new URL(siteInfoBean.getSSiteURL()); PkO(Y!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6n4S$a  
httpConnection.setRequestProperty("User-Agent","NetFox"); \EqO;A%<  
,peFNpi  
0(.C f.B~  
int responseCode=httpConnection.getResponseCode(); of<OOh%3  
if(responseCode>=400) DvKMb-*S  
{ S+ x [1#r  
processErrorCode(responseCode); U_04QwhK7  
return -2; //-2 represent access is error A]slssE+  
} N* QI>kzU  
#`EMK   
L>*|T[~  
String sHeader; ;!Mg,jlQ  
ttxOP  
hTqJDP"&F  
for(int i=1;;i++) Cr"hu;  
{ svII =JB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Xp@OIn  
//Utility.log(in.readLine()); .- o,_eg1f  
sHeader=httpConnection.getHeaderFieldKey(i); p_5+L@%Gb  
if(sHeader!=null) ={d\zjI$  
{ .4-S|]/d,  
if(sHeader.equals("Content-Length")) 4cL=f  
{ oWT0WS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); GR9F^Y)K{  
break; 0_)\e  
} NIGFu{S  
} _TiF}b!hi  
else 3J{'|3x  
break; "^7Uk#! 7  
} Ro69woU  
} ZGBcy}U(k  
catch(IOException e){e.printStackTrace ();} r>OE[C69  
catch(Exception e){e.printStackTrace ();} 9)`wd&!  
_;+&'=6.[  
:I8t}Wg  
Utility.log(nFileLength); 1,,:4 *)  
~M=`f{-$K  
(nG  
return nFileLength; Si(?+bda0c  
} }r[BME  
[\y>Gv%  
jLU)S)  
//保存下载信息(文件指针位置) SX.v5plhc  
private void write_nPos() XPSWAp)  
{  G%{jU'2  
try{ fzcT(y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Xb {y*',  
output.writeInt(nStartPos.length); 2oRmro  
for(int i=0;i<nStartPos.length;i++) F ry5v?22  
{ 1U!CD-%(  
// output.writeLong(nPos); /6fsh7 \  
output.writeLong(fileSplitterFetch.nStartPos); hvwr!(|W  
output.writeLong(fileSplitterFetch.nEndPos); -`JY] H  
} N[%IrN3  
output.close(); Ex{]<6UAu  
} K>U &jH  
catch(IOException e){e.printStackTrace ();} (G Y`O  
catch(Exception e){e.printStackTrace ();} /nNHI34  
} %1<|.Dmd  
+Y+kx"8  
H3b`)k sFr  
//读取保存的下载信息(文件指针位置) "7d_$.Z  
private void read_nPos() MH-,+-Eq  
{ ! `o =2b=N  
try{ "|H0 X#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >ZT3gp?E  
int nCount = input.readInt(); psBBiHB[L  
nStartPos = new long[nCount]; 6/ )A6Tt  
nEndPos = new long[nCount]; Cq=c'(cX  
for(int i=0;i<nStartPos.length;i++) Yi3DoaS;"  
{ kBkhuKd)V  
nStartPos = input.readLong(); += QboUN  
nEndPos = input.readLong(); TqC"lO>:Q  
} 43YusUv  
input.close(); 4_eq@'9-q  
} BR*U9K|W  
catch(IOException e){e.printStackTrace ();} G!uxpZ   
catch(Exception e){e.printStackTrace ();} wS*UXF&f  
} te_D  ,  
.$rcTZ  
G9]GK+@&F  
private void processErrorCode(int nErrorCode) '?nhpT^  
{ u<[Y6m  
System.err.println("Error Code : " + nErrorCode); l%fl=i~oN  
} ;iWCV& >w  
W NCdk$  
xE:p)B-]  
//停止文件下载 :v+ 39  
public void siteStop() zB4gnVhus|  
{ juM?y'A  
bStop = true; &j$k58mX  
for(int i=0;i<nStartPos.length;i++) :DEZ$gi  
fileSplitterFetch.splitterStop(); mOBS[M5*  
59|Tmf(dS;  
MZ.Jkf(  
} A-kI_&g\Og  
} +Z+]Tqo  
//负责部分文件的抓取 2X:n75()  
**FileSplitterFetch.java pq4frq  
*/ j`bOJTBE  
package NetFox; V@F~Cx  
n#iL[ &/Aw  
z`W$/tw"  
import java.io.*; Y,{Xv  
import java.net.*; K-/fq=z  
s;L7 _.hH@  
D n^RZLRhy  
public class FileSplitterFetch extends Thread {   ~*RNJ  
h c "n?  
3OTSLF/  
String sURL; //File URL #'8E%4  
long nStartPos; //File Snippet Start Position 6<2 7}S  
long nEndPos; //File Snippet End Position y3l sAe#  
int nThreadID; //Thread's ID 8ARpjYZP  
boolean bDownOver = false; //Downing is over Q~`n%uYg\{  
boolean bStop = false; //Stop identical Oo,<zS=ICk  
FileAccessI fileAccessI = null; //File Access interface Pp?J5HW  
,JR7N_"I  
B<W{kEY  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2`x[y?Tn  
{ NVQ IRQ.  
this.sURL = sURL; r__uPyIMG/  
this.nStartPos = nStart; =2< >dM#`  
this.nEndPos = nEnd; 75a3H`  
nThreadID = id; h_J 'dJS  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,+f'%)s_x  
} KV Mm<]Z  
EBJaFz'  
y5>H>NS  
public void run() *9G;n!t  
{ SJL?(S*  
while(nStartPos < nEndPos && !bStop) 9R!.U\sq  
{ WVKzh  
cxVnlgq1  
,+0_kndR  
try{ dx|j,1e  
URL url = new URL(sURL); {'JoVJKv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0q81H./3  
httpConnection.setRequestProperty("User-Agent","NetFox"); f"S^:F0  
String sProperty = "bytes="+nStartPos+"-"; [H!V  
httpConnection.setRequestProperty("RANGE",sProperty); 2x0[@cT i?  
Utility.log(sProperty); V5m4dQ>t  
uSH.c>  
(JOge~U  
InputStream input = httpConnection.getInputStream(); 1aKY+4/G  
//logResponseHead(httpConnection); qWdL|8  
[W` _`  
2\_}81 hM  
byte[] b = new byte[1024]; /K1YDq<=  
int nRead; v. !L:1@I.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) H_Vf _p?  
{ #49,7OBU  
nStartPos += fileAccessI.write(b,0,nRead); JpN+'/  
//if(nThreadID == 1) Fq:BRgCE  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S'q (Qo  
} 0I1bY]*  
^2=11  
@#;2P'KL  
Utility.log("Thread " + nThreadID + " is over!"); t ?rUbN  
bDownOver = true; Y}QtgZEt  
//nPos = fileAccessI.write (b,0,nRead); a=Pl3Uo  
} du  Pzt  
catch(Exception e){e.printStackTrace ();} U2seD5I  
} w(0's'  
} ]F P(,:Yw  
R]H/Jv\'  
}9=VhC%J  
//打印回应的头信息 Bg {"{poy  
public void logResponseHead(HttpURLConnection con) -Z9e}$q$,  
{ JHBX'1GQa  
for(int i=1;;i++) sSU p7V  
{ 26?yEd6^Z  
String header=con.getHeaderFieldKey(i); pkQEry&Z  
if(header!=null) n'>`2 s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #f d ;]  
Utility.log(header+" : "+con.getHeaderField(header)); bejvw?)S.  
else |bA\>%~  
break; 3U^E<H  
} Xf(H_&K  
} qf-0 | w  
rZEL7{  
Dn1aaN6  
public void splitterStop() f5'Cq)Vw_  
{ _NA[g:DZ&O  
bStop = true; :+06M@  
} K 0R<a~  
S}WQ~e  
{oOzXc6o  
} hV_bm@f/y  
8R0Q-,'  
'W(!N%u  
/* 1ayL*tr  
**FileAccess.java jOV,q%)^,:  
*//文件访问(定位,写) EdR1W~JZ  
package NetFox; KPTp91  
import java.io.*;  xY v@  
xvU@,bzz  
F/}(FG<'>I  
public class FileAccessI implements Serializable{ WTK )SKa,.  
W!6&T [j>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Mwm9{1{  
RandomAccessFile oSavedFile; cHP~J%&L  
long nPos; <a_ytSoG1  
I54`}Npp  
iW oe  
public FileAccessI() throws IOException |T3F:],`  
{ 2z#gn9Wb  
this("",0); oy{ {d  
} (@X].oM^y  
TuR.'kE@  
`,~8(rIM  
public FileAccessI(String sName,long nPos) throws IOException Ts)ox}rYVm  
{ Y~,ZBl,  
oSavedFile = new RandomAccessFile(sName,"rw"); HFlMx  
this.nPos = nPos; 6)5Akyz4V  
oSavedFile.seek(nPos); A}"aH  
} fRlO.!0(  
jxeZ,w o  
9\ f%+?p  
public synchronized int write(byte[] b,int nStart,int nLen) f~a]og5|G  
{ iTUOJ3V7i  
int n = -1; _e4%<!1  
try{ ( &N`N1  
oSavedFile.write(b,nStart,nLen); q#pD}Xe$  
n = nLen; 2":{3=oW~  
} %OT} r  
catch(IOException e) #z$g1\v  
{ Cg#@JuwHa  
e.printStackTrace (); T'8d|$X  
} L JW0UF|  
s[2>r#M  
MbbKo-7F$  
return n; ` b$u w  
} h_*!cuH  
}LYK:?_/  
_|1m]2'9  
} Wy:xiP  
MVDEVq0  
0vYHx V  
/* ^p7g[E&  
**SiteInfoBean.java lE|Hp  
*/ 7gxC xfL$  
package NetFox; Cr&,*lUo  
=pa F6!AB  
R%EpF'[~[  
public class SiteInfoBean { <36z,[,kZ@  
Ng,< 4;  
qL;u59  
private String sSiteURL; //Site's URL K (px-jY  
private String sFilePath; //Saved File's Path LWX,u  
private String sFileName; //Saved File's Name HE BKRpt  
private int nSplitter; //Count of Splited Downloading File jVdRy{MH  
?mq<#/qb  
d$ f3 Cre  
public SiteInfoBean() aWg*f*2f  
{//nSplitter的缺省值为5 Z4VNm1qs  
//default value of nSplitter is 5 md S`nhb  
this("","","",5); <0sT  
} GI. =\s  
B QxU~s  
.=`r?#0  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0D==0n  
{ v$JhC'  
sSiteURL= sURL; e^%>_U  
sFilePath = sPath; hf('4^  
sFileName = sName; |i~Ab!*8n  
this.nSplitter = nSpiltter; DuvI2Z WP]  
(?W[#.=7  
oj$^87KX  
} A(2!.Y 2?*  
:*g3PhNE  
xPp\OuwK  
public String getSSiteURL() ?yNg5z  
{ 1w~@'ZyU  
return sSiteURL; I%?ia5]H  
} wgPkSsuBuC  
!8jr $  
N.1 @!\z@@  
public void setSSiteURL(String value) h+d  \u  
{ u&-Zh@;Q7  
sSiteURL = value; ?7|6jTIs  
} ]ucz8('  
X}5}M+'~  
xtq='s8e  
public String getSFilePath() P \k5%  
{ \:/~IZdzF  
return sFilePath; rf\A[)<:  
} &Cykw$s  
_$vAitUe4S  
0x1#^dII  
public void setSFilePath(String value) j t6q8  
{ KEfx2{k b  
sFilePath = value; rEfo)jod  
} 3v?R"2\qS  
aePLP  
 Oye:V  
public String getSFileName() TQ`4dVaf  
{ ^hyY,X  
return sFileName; k. @OFkX.  
} {9_}i#,vR  
K.l7yBm  
552yzn1  
public void setSFileName(String value) i pi^sCYp  
{ _&U.DMt2 C  
sFileName = value; ~jOn)jBRZ  
} OA?pBA  
Uja`{uc  
lKT<aYX  
public int getNSplitter() x sN)a!  
{ 9*b(\Z)N  
return nSplitter; p*ic@n*G  
} rAwuWM@BIg  
:GBM`f@  
m]"13E0*x  
public void setNSplitter(int nCount) fBw"<J{  
{ Tj3xK%K_r3  
nSplitter = nCount; a 9H^e<g  
} ;jZf VRl  
} E(p*B8d  
qh)10*FB  
!M*$p Qi}  
/* XI/LVP,.  
**Utility.java kaG@T,pH(  
*/ &CcUr#|  
package NetFox; s%OPoRE  
\LbBK ~l-I  
VX{9g#y$j  
public class Utility { 1RM@~I$0  
PYhRP00}M  
2M`:/shq  
public Utility() a\]g lw\;  
{ HA#9y;\  
m6 V L  
edZhI  
} eWw# T^  
;GF+0~5>  
//线程睡眠 o1^Rx5  
public static void sleep(int nSecond) $AyE6j_1gX  
{ _Gb O>'kE  
try{ X={Z5Xxr"  
Thread.sleep(nSecond); w;=g$Bn  
} *%p`Jk-U  
catch(Exception e) H7Y :l0b  
{ 0~( f<:  
e.printStackTrace (); Z6\H4,k&  
} d:&=|kKw  
} cy{ ado2  
QRFBMq}'  
//日志 .d?2Kc)SV\  
public static void log(String sMsg) @en*JxIM  
{ !QXPn}q^0  
System.err.println(sMsg); i[7<l&K]  
} 2M$^|j:[  
n=1_-)  
8{)j"rghah  
public static void log(int sMsg) l1#F1q`^t  
{ }T1.~E  
System.err.println(sMsg); FA7q pc  
} ~[ZRE @  
} 3<A$lG  
qC4Q+"'  
`-)Hot)  
/* 1n-+IR"  
**TestMethod.java FofeQ  
*/ A(v5VvgZE  
package NetFox; {1Hs5bg@  
Q xm:5P  
)0UXTyw^  
public class TestMethod { ~M Mv+d88  
AR?1_]"=  
a]4h5kJ';  
public TestMethod() 'fS&WVR?  
{ ///xx/weblogic60b2_win.exe i8Xz'Sw07  
try{ FhJtiw@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6*r#m%|   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Zog&:]P'F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fMl uVND  
fileFetch.start(); `2l j{N  
} b-Xc6f  
catch(Exception e){e.printStackTrace ();} J *nWCL  
1ww#]p`1  
mi'3ibCG  
} ~/m=Q<cV  
dW#T1mB  
5h7M3s  
public static void main(String[] args) ,We'A R3X  
{ -.t/c}a#  
new TestMethod(); ^=@`U_(,G  
} \.K4tY+V  
} 7M,(!*b  
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