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http断点续传简单实现(java)

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/* d8N{sT  
**SiteFileFetch.java t3P$UR%  
*/ Qs\m"yx  
package NetFox; GXk]u  
import java.io.*; (U`<r-n\n  
import java.net.*; jWpm"C  
Vt4KG+zm  
G;jX@XqZ  
public class SiteFileFetch extends Thread { -l(G"]tRB  
i#4}xvi  
l%\p  
SiteInfoBean siteInfoBean = null; //文件信息Bean  $I*<gn9  
long[] nStartPos; //开始位置 w20)~&LE-  
long[] nEndPos; //结束位置 1n3XB+*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g"}j  
long nFileLength; //文件长度 9-ei#|Vnt[  
boolean bFirst = true; //是否第一次取文件 c_~tCKAZ   
boolean bStop = false; //停止标志 kleE\ 8_  
File tmpFile; //文件下载的临时信息 ) dB?Ep|  
DataOutputStream output; //输出到文件的输出流 n{*A<-vL  
Rz03he  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) xR~9|H9a  
public SiteFileFetch(SiteInfoBean bean) throws IOException >;s!X(6 b  
{ $cSmubZK  
siteInfoBean = bean; U;w| =vM  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (C9{|T+h  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); DeK&_)g| Z  
if(tmpFile.exists ()) Pl/B#Sbf'  
{ ]H-5    
bFirst = false; ] lBe   
read_nPos(); :S['hBMN  
} Drn{ucIs  
else ~Onj| w7  
{ D\~s$.6B  
nStartPos = new long[bean.getNSplitter()]; Sn o7Ru2  
nEndPos = new long[bean.getNSplitter()]; R,3E_me"}  
} 5,Q3#f~!  
)^Ha?;TS  
iTX:*$~I  
1\'?.  
} R1!F mZW8  
C]X:@^Hy  
"7w~0?}  
public void run() .,-,@ZK  
{ .2K4<UOAbm  
//获得文件长度 ,5Vc  
//分割文件 >rbHpLm1`  
//实例FileSplitterFetch 8Ce|Q8<8]  
//启动FileSplitterFetch线程 UxGr+q  
//等待子线程返回 o+NPe36  
try{ z XI [f  
if(bFirst) `&3hfiI}  
{ EnM }H9A  
nFileLength = getFileSize(); )+Nm @+B  
if(nFileLength == -1) 0XkLWl|k  
{ v?BVUH>#9  
System.err.println("File Length is not known!"); /*V:Lh  
} o {W4@:Ib  
else if(nFileLength == -2) G,{=sFX  
{ :Dh\  
System.err.println("File is not access!"); a {4Wg:  
} r Jo8|  
else Q140b;Z  
{ 4qd =]i  
for(int i=0;i<nStartPos.length;i++) T(GEFnt Y  
{ 3`Ug]<m  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tQrF A2F  
} X0QY:?  
for(int i=0;i<nEndPos.length-1;i++) iY|zv|;]=  
{ ;s^br17z~  
nEndPos = nStartPos[i+1]; *A^j>lV  
} wqB 5KxO  
nEndPos[nEndPos.length-1] = nFileLength; v+), uj  
} 6w?l I  
} +qWrm |O]  
~PTqR2x  
gv6}GE  
//启动子线程 Zb \E!>V  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vU4Gw4  
for(int i=0;i<nStartPos.length;i++) 0mb|JoE(  
{ zL^`r)H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Kyr3)1#J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \! *3bR  
nStartPos,nEndPos,i); n?UFFi+a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Gp l  
fileSplitterFetch.start(); OI8Hf3d=  
} =do*(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M1Frn n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); lc:dKGF6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (plsL   
nEndPos = " + nFileLength); E43Gk!/|(  
// fileSplitterFetch[nPos.length-1].start(); #`g..3ey  
/'[m6zm]  
w[K!m.p,u  
//等待子线程结束 C;m,{MD  
//int count = 0; 9<" .1  
//是否结束while循环 (t.OqgY  
boolean breakWhile = false; qe/|u3I<lF  
i[+cNJ|$B0  
A89n^@  
while(!bStop) ]* #k|>Fl  
{ Np.] W(  
write_nPos(); @5[9iY  
Utility.sleep(500); Tc3~~X   
breakWhile = true; nEG+TRZ)\  
'j#J1 xwJ  
oP"X-I  
for(int i=0;i<nStartPos.length;i++) UI?AM 34  
{ @) \{u$  
if(!fileSplitterFetch.bDownOver) 1xBg^  
{ Q.b<YRZ  
breakWhile = false; x;w^&<hQ\  
break; G*`H2-,  
} ,Ky-3p>  
} bV3az/U  
if(breakWhile) =V[ey  
break; "3?N*,U_  
@W|N1,sp  
!5wuBJ0  
//count++; mY'c<>6t  
//if(count>4) aFbIJm=!  
// siteStop(); US.7:S-r"  
} q^I/  
h1A/:/_M6  
pBbfU2p  
System.err.println("文件下载结束!"); >RTmfV  
} 7GFE5>H  
catch(Exception e){e.printStackTrace ();} DHnO ,"  
} ^&Exa6=*FT  
6-+q3#e  
NDqvt$  
//获得文件长度 C4].egVg  
public long getFileSize() "44A#0)B'l  
{ NI%&Xhn!*>  
int nFileLength = -1; Cj +{%^#  
try{ H}p5qW.tH:  
URL url = new URL(siteInfoBean.getSSiteURL()); @:ojt$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zK_+UT  
httpConnection.setRequestProperty("User-Agent","NetFox"); iPuX  
2VZdtz  
[bK5q;#U4  
int responseCode=httpConnection.getResponseCode(); h{5K9$9=  
if(responseCode>=400) 7<Yf  
{ $oo`]R_   
processErrorCode(responseCode); 4[.DQ#r  
return -2; //-2 represent access is error C 7a$>#%  
} GdlzpBl  
eF06B'uL  
rZi\  
String sHeader; p!_3j^"{  
C@ns`Eh8w  
P\nz;}nv  
for(int i=1;;i++) RP9jZRDbZ  
{ nF#1B4b>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :ot^bAyt|  
//Utility.log(in.readLine()); |GLh|hr  
sHeader=httpConnection.getHeaderFieldKey(i); b<]Ae!I'  
if(sHeader!=null) m8:9Uv  
{ *%#Sa~iPo  
if(sHeader.equals("Content-Length")) N+3]C9 2o  
{ +5k^-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ER'zjI>t@  
break; {: H&2iF  
} s{:l yp  
} N6%wHNYZ  
else ^F?}MY>  
break; .m^L,;+2  
} e%wzcn  
} {pR4+g  
catch(IOException e){e.printStackTrace ();} ~ 7^#.  
catch(Exception e){e.printStackTrace ();} xaw)iC[gI{  
|Vj@;+/j  
EG&97l b  
Utility.log(nFileLength); )/{zTg8$?/  
p "Cxe  
R?E< }\!  
return nFileLength; Xk]:]pl4W  
} /]@1IC{Lk  
a:V2(nY  
2Vwv#NAV k  
//保存下载信息(文件指针位置) 1!P\x=Nn_  
private void write_nPos() 7/>#yR  
{ Hdxon@,+cd  
try{ jY|fP!?[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); m5'nqy F  
output.writeInt(nStartPos.length); .I#ss66h  
for(int i=0;i<nStartPos.length;i++) {Y7dE?!`7  
{ +~{Honj[  
// output.writeLong(nPos); vWh]1G#'p[  
output.writeLong(fileSplitterFetch.nStartPos); &&s3>D^Ta  
output.writeLong(fileSplitterFetch.nEndPos); f$|AU- |<  
} a^xt9o`  
output.close(); Kwmtt  
} '&+5L.  
catch(IOException e){e.printStackTrace ();} 02RZ>m+  
catch(Exception e){e.printStackTrace ();} 6^VPRp  
} EC`=nGF  
TJ_pMU  
iY;>LJmp  
//读取保存的下载信息(文件指针位置) @aC9O 9|~  
private void read_nPos() uFYcVvbT@  
{ khQ@DwO*\=  
try{ (8td0zq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  \<u  
int nCount = input.readInt(); T?k!%5,Kj  
nStartPos = new long[nCount]; H~<w*[uT  
nEndPos = new long[nCount]; Xx?~%o6  
for(int i=0;i<nStartPos.length;i++) =OamN7V=  
{ S.R|Bwj}(Y  
nStartPos = input.readLong(); q(\kCUy!  
nEndPos = input.readLong(); _@@.VmZL  
} Csf!I@}Z  
input.close(); pB:/oHV  
} 3XSfXS{lwP  
catch(IOException e){e.printStackTrace ();} 21sXCmYR,t  
catch(Exception e){e.printStackTrace ();} {v}BtZ  
} (Tv~$\=  
TOw;P:-  
bc]SY =  
private void processErrorCode(int nErrorCode) `q m$2  
{ NiBly  
System.err.println("Error Code : " + nErrorCode); cq"#[y$r  
} f-`C1|\w  
CLgfNrW~  
~v6]6+   
//停止文件下载 '1"vwXJ"  
public void siteStop() ^i!I0Q2yd  
{ vw6DHN)k  
bStop = true; qGdoRrp0Ov  
for(int i=0;i<nStartPos.length;i++) ST1c`0e  
fileSplitterFetch.splitterStop(); #+8G`  
Sb.%B^O  
vLIaTr gz  
} x5R|,bY  
} 6PT"9vR`)  
//负责部分文件的抓取 +?v2MsF']  
**FileSplitterFetch.java Zg$RiQ^-{J  
*/ B^@X1EE  
package NetFox; Slv91c&md,  
w>wzV=R  
H>F j  
import java.io.*; 9`tSg!YOh  
import java.net.*; k]rc -c-  
'fPDODE  
"t%Jj89a\  
public class FileSplitterFetch extends Thread { C."\ a_p  
+!mEP>  
:6J&%n  
String sURL; //File URL dWP<,Z>  
long nStartPos; //File Snippet Start Position M{g.x4M@W  
long nEndPos; //File Snippet End Position }H:wgy`  
int nThreadID; //Thread's ID jI%glO'2  
boolean bDownOver = false; //Downing is over ^s\T<;  
boolean bStop = false; //Stop identical d:{}0hmxI  
FileAccessI fileAccessI = null; //File Access interface :!wl/X ~  
.Bojb~zt  
<"yL(s^u"  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?\$6"c<G  
{ Of>2m<  
this.sURL = sURL; O9rA3qv B  
this.nStartPos = nStart; S0`u!l89(  
this.nEndPos = nEnd; ! ~tf0aY  
nThreadID = id; Xi;<O&+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]CDUHz  
} R>B6@|}?  
<R?S  
NAOCQDk{  
public void run() Qna*K7kv  
{ beB3*o  
while(nStartPos < nEndPos && !bStop) $LVzhQlD  
{ xnHB <xrE}  
tIS.,CEQF  
S]NT+XM  
try{ Lngf,Of.e  
URL url = new URL(sURL); &+3RsIl W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "R"{xOQl  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'Y/kF1,*  
String sProperty = "bytes="+nStartPos+"-"; r7FJqd  
httpConnection.setRequestProperty("RANGE",sProperty); GT\ yjrCd  
Utility.log(sProperty); w c  
\BX9Wn*)a  
F\^\,hy  
InputStream input = httpConnection.getInputStream(); {yDQncq'^  
//logResponseHead(httpConnection); 8tVSai8[  
%y7ZcH'  
iNc!z A4  
byte[] b = new byte[1024]; =~5N/!  
int nRead; YRMe<upo  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) bGkLa/?S  
{ 'Va<GHr>+  
nStartPos += fileAccessI.write(b,0,nRead); al9( 9)  
//if(nThreadID == 1) =zu;npM  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8nWPt!U:  
} Uf MQ?(,  
gAVD-]`  
OZC yg/K  
Utility.log("Thread " + nThreadID + " is over!"); T+B8SZw#}!  
bDownOver = true; +v$W$s&b-h  
//nPos = fileAccessI.write (b,0,nRead); I@\D tQZ  
} 9tb-;|  
catch(Exception e){e.printStackTrace ();} e7bMK<:r  
} [4aw*M1z}.  
} e=aU9v L  
6nR EuT'k  
o 0T1pGs'  
//打印回应的头信息 'IT]VRObP  
public void logResponseHead(HttpURLConnection con) '$eJATtC  
{ J Vxja<43  
for(int i=1;;i++) ~mwIr  
{ k2tSgJW  
String header=con.getHeaderFieldKey(i); 3o0ZS^#eB  
if(header!=null) ~I9o *cq  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); w^("Pg`  
Utility.log(header+" : "+con.getHeaderField(header)); Pf<yLT]  
else =9W\;xE S  
break; Yi)s=Q:  
} +S[3HX7H  
} 7!h> < sx  
MJrPI a[pN  
!s?SI=B8  
public void splitterStop() vU5}E\Ny  
{ 6GPI gPL,  
bStop = true; mwyB~,[d+W  
} aWH  
M_-L#FHX  
jwBJG7\  
} gujP{Z  
eO(U):C2  
!c{F{ t-a  
/* 1_A_)l11  
**FileAccess.java `C C=?E  
*//文件访问(定位,写) yP>025o't  
package NetFox; 8D,*_p  
import java.io.*; 6>)nkD32g  
Bf]Bi~w<  
iP;" -Mj  
public class FileAccessI implements Serializable{ NdSuOkwwt  
Ej 5_d  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -{8K/!  
RandomAccessFile oSavedFile; #.[eZ[  
long nPos; KX 7 fgC  
B2P@9u|9  
CaO-aL  
public FileAccessI() throws IOException P9f`<o  
{ 2<y9xvp  
this("",0); @2a!T03  
} %2\tly!{ %  
z7gX@@T  
CfSP*g0rW  
public FileAccessI(String sName,long nPos) throws IOException 3Jt# Mp  
{ vJ=Q{_D=\  
oSavedFile = new RandomAccessFile(sName,"rw"); CswKT 9  
this.nPos = nPos; i%i />;DF  
oSavedFile.seek(nPos); 1JfZstT  
} 0Ci/-3HV!  
{>9ED.t  
 X(X[v]  
public synchronized int write(byte[] b,int nStart,int nLen) ,Kl?-W@  
{ X-kOp9/.  
int n = -1; +egwZ$5I  
try{ n*A1x8tn  
oSavedFile.write(b,nStart,nLen); _oCNrjt9  
n = nLen; {\%I;2X  
} XD|g G  
catch(IOException e) x: _[R{B  
{ |*UB/8C^/!  
e.printStackTrace (); u4w!SD  
} z\A ),;  
S#v3%)R  
uf9&o#  
return n; %)?jaE}[  
} RR ^7/-  
?6&8-zt1?  
H~nZ=`P9&  
} FX|&o >S(8  
%dg[ho  
K)~aH  
/* oD9n5/ozo  
**SiteInfoBean.java zU+q03l8Ur  
*/ 0 }od Q#  
package NetFox; QAp]cE1ew  
y^}u L|=  
$Oy&PO e  
public class SiteInfoBean { BLO ]78  
?z&%VU"  
7 [1|(6$  
private String sSiteURL; //Site's URL iW>^'W#  
private String sFilePath; //Saved File's Path %kV7 <:y  
private String sFileName; //Saved File's Name p^|l ',e  
private int nSplitter; //Count of Splited Downloading File ,&WwADZ-s  
=urGs`\  
4}v|^_x-i  
public SiteInfoBean() ;-kDJ i  
{//nSplitter的缺省值为5 BR@m*JGajz  
//default value of nSplitter is 5 URrx7F98  
this("","","",5); B6k<#-HAT  
} 6X%g-aTs  
ix4]^  
h )5S4)  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ybE 2N  
{ YnU)f@b#  
sSiteURL= sURL; T!KwRxJ23  
sFilePath = sPath; HdI)Z<Krp  
sFileName = sName; 9%iQ~   
this.nSplitter = nSpiltter; N\ !  
/}m*|cG/  
o!":mJy  
} y7fy9jQ 8.  
SnmUh~`L~  
a~$Y;C_#<  
public String getSSiteURL() 3S7"P$q  
{ z77>W}d  
return sSiteURL; @e GBF Ns  
} >VkBQM-%  
 3}8o 9  
0~^RHb.NA8  
public void setSSiteURL(String value) mQ"uG?NE  
{ pLtw|S'4  
sSiteURL = value; 2icQ (H;  
} e@W+ehx"  
m)Kg6/MV.  
-;L'Jb>s76  
public String getSFilePath() , i5_4  
{ WJnGF3G>  
return sFilePath; @ CmKF  
} !EhKg)y=  
Nb`qM]&  
(;},~( 2B  
public void setSFilePath(String value) IUFc_uL@\  
{ @nY]S\if  
sFilePath = value; src+z#  
} `{G&i\"n  
>9dD7FH  
! I0xq"  
public String getSFileName() 7}UG&t{  
{ 6_bL<:xtY  
return sFileName; =zcvR {Dkp  
} yEI@^8]s  
ezp%8IZ;  
^0OP&s;"  
public void setSFileName(String value) bTaKB-  
{ i9DD)Y<  
sFileName = value; M>]A! W=  
} \MOwp@|y  
j,+]tHC-  
]$[sfPKA  
public int getNSplitter() ujX; wGje  
{ V^5d5Ao  
return nSplitter; Km8aHc]O~  
} D![v{0er  
:]m.&r S,  
+ '_t)k^  
public void setNSplitter(int nCount) LnI  
{ rQVX^  
nSplitter = nCount; {}$7Bp  
} EyE#x_A  
} Z_\p8@3aH  
MVsFi]-  
akzGJ3g  
/* 4\Y5RfLB_  
**Utility.java 0+*NHiH  
*/ pi?MAE*f  
package NetFox; GT&}Burl/n  
-V|"T+U  
%'=*utOxy  
public class Utility { zXn-E  
"s(~k  
Go)$LC0Mi  
public Utility() lb-1z]YwQ  
{ LKu\Mh|  
S%i^`_=Q  
ZNX38<3h  
} l4oyF|oJTH  
Icnhet4  
//线程睡眠 l}))vf=i  
public static void sleep(int nSecond) 27e!KG[&  
{ YB5"i9T2  
try{ g"evnp  
Thread.sleep(nSecond); -)`_w^Ox  
} 5QMra5Nk  
catch(Exception e) %L+q:naZe  
{ L=4+rshl!_  
e.printStackTrace (); `r`8N6NQ&]  
} :}lqu24K  
} X g6ezlW  
FPDTw8" B;  
//日志 CI'RuR3y]Z  
public static void log(String sMsg) FmL]|~  
{ ::|~tLFu  
System.err.println(sMsg); `<C<[JP:o  
} a[-!X7,IU  
bO=|utpk  
w7V\_^&Id  
public static void log(int sMsg) to'7o8Z  
{ :aesG7=O  
System.err.println(sMsg); }Y~Dk]*  
} WPRk>j  
} &|XgWZS5  
nG'Yo8I^5  
%"f85VfZ  
/* sg,\!'  
**TestMethod.java ^# $IoW  
*/ &`qYe)1Eo  
package NetFox; QG*hQh  
FXr^ 4B}  
7"Xy8]i{z  
public class TestMethod { ~Fb@E0 }!  
=CFjG)L  
Gt*<Awn8  
public TestMethod() {Z/iYHv~#c  
{ ///xx/weblogic60b2_win.exe N 8[r WJ#  
try{ qR.FjQOvn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iOZ9A~Ywy  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M1eh4IVE?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "9xJ},:-  
fileFetch.start(); `e ZDG  
} (/uN+   
catch(Exception e){e.printStackTrace ();} !ldEy#"X  
JAHg_!  
4vL\t uoz  
} igQzL*X  
jP<6J(  
"=Z=SJ1D  
public static void main(String[] args) V<WWtu;3  
{  C@*x  
new TestMethod(); -F/)-s6#!'  
} FZgf"XM>  
} YQD `4ND  
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