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http断点续传简单实现(java)

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/* zKThM#.Wa  
**SiteFileFetch.java 8:K_S a%  
*/ L;fz7?_j  
package NetFox; vd/BO  
import java.io.*; cbW=kQc_  
import java.net.*; %yK- Q,'O  
.2y @@g  
Gn;^]8d  
public class SiteFileFetch extends Thread { I_|W'%N]  
% -.V6}V  
 ~;uU{TT  
SiteInfoBean siteInfoBean = null; //文件信息Bean MR zY<MD  
long[] nStartPos; //开始位置 Gz2\&rmN  
long[] nEndPos; //结束位置  KON^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 0 > QqsQ  
long nFileLength; //文件长度 =-avzuy#  
boolean bFirst = true; //是否第一次取文件 uJa.]J~L=  
boolean bStop = false; //停止标志 Nj +^;Y  
File tmpFile; //文件下载的临时信息 %K0Wm#)  
DataOutputStream output; //输出到文件的输出流 DHuUEv<  
`:d\L H  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) [Bj\h7 G  
public SiteFileFetch(SiteInfoBean bean) throws IOException zek>]l`!  
{ !E^\)=E)P  
siteInfoBean = bean; ~SI G0U8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4W=fQx]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $5DlCN  
if(tmpFile.exists ()) | NyANsI  
{ L#fK ,r8  
bFirst = false; sVe<l mL  
read_nPos(); 0JW =RW  
} VdGpreRPC  
else (Mw+SM3<  
{ HT6$|j  
nStartPos = new long[bean.getNSplitter()]; eKRE1DK  
nEndPos = new long[bean.getNSplitter()]; <Vh }d/  
} kpMo7n  
/$9We8  
Ged} qXn  
EIF  
} E0.o/3Gw6  
*DQa6,b  
KfQ?b_H.  
public void run() DeI3(o7  
{  }- wK  
//获得文件长度 i;\n\p1  
//分割文件 |gU)6}V@  
//实例FileSplitterFetch GE=PaYz  
//启动FileSplitterFetch线程 [EK@f,iM  
//等待子线程返回 Sa/]81 aG  
try{ .etG>tH  
if(bFirst) tD,I7%|@  
{ J|([(  
nFileLength = getFileSize(); D-e?;<  
if(nFileLength == -1) #X0Xc2}{f  
{ ? U =Mdw  
System.err.println("File Length is not known!"); tjQ6[`  
} h+Y>\Cxg  
else if(nFileLength == -2) gL`aLg_  
{ #VxN [770  
System.err.println("File is not access!"); D'#,%4P,e\  
} b"Jr_24t3v  
else U|8?$/*\  
{ )5u#'5I>  
for(int i=0;i<nStartPos.length;i++) 0n\AUgVPF  
{ h<qi[d4X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [MD"JW?4B  
} V 7D<'!  
for(int i=0;i<nEndPos.length-1;i++) 6q,CEm  
{ O\h%ZLjfO  
nEndPos = nStartPos[i+1]; H|/"'t OZ  
} bD?gwhAKA  
nEndPos[nEndPos.length-1] = nFileLength; )~IOsTjI  
} fS p  
} #}Bv/`t  
)( pgJLW  
T "#DhEM  
//启动子线程 ,rOh*ebF  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Tq?f5swsI  
for(int i=0;i<nStartPos.length;i++) A,c_ME+DVB  
{ Z A}!Rzo  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $QwzL/a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ),$^h7[n  
nStartPos,nEndPos,i); iH>b"H >  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V7vojm4 O  
fileSplitterFetch.start(); ZgmK~iJ  
} C~PP}|<~V  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 65tsJ"a<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {mLv?"M]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "2 D{X  
nEndPos = " + nFileLength); q(BRJ(  
// fileSplitterFetch[nPos.length-1].start(); Iz&d S?p_  
Sg13Dp @x  
8E>2 6@.  
//等待子线程结束 [ C!m,4  
//int count = 0; SQN{/")T  
//是否结束while循环 g_eR&kuh  
boolean breakWhile = false; rEWuWv$  
cW ?6Iao  
(l/i#  
while(!bStop) ebLt:gGo  
{ ~`5[Li:eP  
write_nPos(); |BO5<`&I  
Utility.sleep(500); ZIc-^&`r=  
breakWhile = true; (e9hp2m  
~se ;L  
xscR Bx  
for(int i=0;i<nStartPos.length;i++) 89W8cJ$yW  
{ ) }k"7"  
if(!fileSplitterFetch.bDownOver) #nKGU"$+  
{ aw7pr464  
breakWhile = false; GT3}'`f B  
break; Rli`]~!w  
} BJqb'H jd  
} @;[.#hK  
if(breakWhile) }( WUZ^L  
break; N8!e(Y K_  
-CPLgT  
]ij:>O@{$  
//count++; MN>U jFA  
//if(count>4) luz,z( v  
// siteStop(); 7K!n'dAi6  
} Ge24Lp;Y 6  
(e<p^T J]  
@VsK7Eo  
System.err.println("文件下载结束!"); 54 f?YR  
} u7-0?  
catch(Exception e){e.printStackTrace ();} uW,rmd  
} ! n?j)p.  
],wzZhA  
^ .Q/iXgh  
//获得文件长度 O)r>AdLGn  
public long getFileSize() p\xsW "=8q  
{ X<H+Z2d  
int nFileLength = -1; w Qp{z  
try{ <a2Kc '  
URL url = new URL(siteInfoBean.getSSiteURL()); u_$Spbc]/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o2LUB)=R'  
httpConnection.setRequestProperty("User-Agent","NetFox"); TJs@V>,  
tNW0 C]  
puGy`9eKv1  
int responseCode=httpConnection.getResponseCode(); AOCiIPw  
if(responseCode>=400) ||4++84{  
{ 2K2jko9'a  
processErrorCode(responseCode); $7\hszjZ  
return -2; //-2 represent access is error ;] #Q!  
} oc&yz>%q  
Zg!E}B:z  
q5~fU$ ,  
String sHeader; ':,p6  
N_E :?Jo  
i)d'l<RA  
for(int i=1;;i++) 65pC#$F<x  
{ 1 BVpv7@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 'gz@UE1  
//Utility.log(in.readLine()); D5 ^WiQ<  
sHeader=httpConnection.getHeaderFieldKey(i); -Cf< #'x_  
if(sHeader!=null) U^$l$"~"  
{ Xdc>Z\0V  
if(sHeader.equals("Content-Length")) skfFj&_T  
{ l@%7] 0!T  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); e@{8G^o>D  
break; L+" 5g@  
} ZD]5"oHY  
} 9Dy/-%Ut9  
else `LCxxpHi|  
break; G(y@Tor+  
} ]]bL;vlw  
} V9kL\Ys  
catch(IOException e){e.printStackTrace ();} <rFY$ ?x  
catch(Exception e){e.printStackTrace ();} >=Un=Q%  
B (dq$+4  
X2p9KC  
Utility.log(nFileLength); 4*9:  
*1;}c z  
P(za8l>  
return nFileLength; ~4+=C\r  
} l]o&D))R  
9:l>FoXS  
d.uJ}=|  
//保存下载信息(文件指针位置) ~ugK&0i[2  
private void write_nPos() ?yt"  
{ W.AN0N  
try{ `$D2w|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hE>i~:~R  
output.writeInt(nStartPos.length); HLcK d`$/  
for(int i=0;i<nStartPos.length;i++) -?WhJ.U  
{ G.a^nQ@e%  
// output.writeLong(nPos); t`X-jr)g  
output.writeLong(fileSplitterFetch.nStartPos); Yxt`Uvc(^h  
output.writeLong(fileSplitterFetch.nEndPos); g^DPb pWxu  
} +LM /< l  
output.close(); e&(Di,%:  
} \^+=vO;A  
catch(IOException e){e.printStackTrace ();} w%[ `'_[  
catch(Exception e){e.printStackTrace ();} N8| ;X  
} ggUJ -M'2h  
NK+iLXC  
,IW$XD  
//读取保存的下载信息(文件指针位置) I2=?H <  
private void read_nPos() Q1Sf7)  
{ JYB<};,  
try{ ` AA[k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <Vk^fV  
int nCount = input.readInt(); L;0ZB=3n  
nStartPos = new long[nCount]; %K_[Bx{B  
nEndPos = new long[nCount]; bqxbOQd  
for(int i=0;i<nStartPos.length;i++) W|@/<K$V  
{ (:>: tcE  
nStartPos = input.readLong(); )0P>o]fWI  
nEndPos = input.readLong(); d aIt `}s  
} ttPa[h{!  
input.close(); $gN1&K  
} 8qfg=mu+ %  
catch(IOException e){e.printStackTrace ();} H|H!VPof]  
catch(Exception e){e.printStackTrace ();} zM^ux!T=  
} m1X0stFRs"  
&LO<!WKQ  
L "L@4 B  
private void processErrorCode(int nErrorCode) )x-iru A:  
{ A|V |vT7cb  
System.err.println("Error Code : " + nErrorCode); 2 fX-J  
} P"%i 4-S  
;N4b~k)  
)A a98Eu?2  
//停止文件下载 O1Gd_wDC/i  
public void siteStop() m?G}%u  
{ h:3`e`J<h  
bStop = true; XX5 ):1  
for(int i=0;i<nStartPos.length;i++) ANy=f-V  
fileSplitterFetch.splitterStop(); jZcjiOX  
5r qjqfFa  
cy)gN g  
} #~54t0|Cd>  
} ip4:px-  
//负责部分文件的抓取 R ;^[4<&  
**FileSplitterFetch.java Cd.pMoS  
*/ `?PZvGi  
package NetFox; }'dnL  
C:g2E[#  
h[%`'(  
import java.io.*; I.j`h2  
import java.net.*; |n3PznV  
EN()dCQHr  
ho2o/>Ef3  
public class FileSplitterFetch extends Thread { o;mXk2  
b7{)B?n  
eMVfv=&L<3  
String sURL; //File URL &"fMiK3  
long nStartPos; //File Snippet Start Position OB8fFd  
long nEndPos; //File Snippet End Position l}%!&V0  
int nThreadID; //Thread's ID kssS,Ogf\_  
boolean bDownOver = false; //Downing is over }%[TJ@R;  
boolean bStop = false; //Stop identical ts3%cRN r  
FileAccessI fileAccessI = null; //File Access interface +/7UM x1  
`f}c 1  
'Zf_/ y  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Er Ji  
{ &h-d\gMJ  
this.sURL = sURL; bV&/)eqv  
this.nStartPos = nStart; M~;mamTP  
this.nEndPos = nEnd; QP)-O*+AA  
nThreadID = id; _L(6F T J  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w"bQxS~$y  
} 5[esW  
3k5OYUk  
I)V2cOrXM  
public void run() {QTfD~z^K  
{ qi}HJkOq  
while(nStartPos < nEndPos && !bStop) {LbNKjn  
{ gAC}  
AYd7qx:~  
EYd`qk 3  
try{ ]]Ypi=<'  
URL url = new URL(sURL); 2BBGJE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wt[MzpRP  
httpConnection.setRequestProperty("User-Agent","NetFox"); bQow,vf  
String sProperty = "bytes="+nStartPos+"-"; 3 zp)!QJi  
httpConnection.setRequestProperty("RANGE",sProperty); AQU4~g mI  
Utility.log(sProperty); {7[^L1  
%+i g7a:  
hAHl+q)w?  
InputStream input = httpConnection.getInputStream(); x"K<@mR5G  
//logResponseHead(httpConnection); m'XzZmI  
Ku*@4#<L6h  
[#$-kd~  
byte[] b = new byte[1024]; E:T<mI?d  
int nRead; XL>Vwd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) q-eC=!#}  
{ a9mLPP  
nStartPos += fileAccessI.write(b,0,nRead); sb Z)z#Tr  
//if(nThreadID == 1) Kjc"K36{L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vr/V_  
} VZ'[\3J  
] NL-)8u  
9xyj,;P>  
Utility.log("Thread " + nThreadID + " is over!"); _N$3c<dY'  
bDownOver = true; R lyF#X#7{  
//nPos = fileAccessI.write (b,0,nRead); )&+j#:  
} ++-HdSHY  
catch(Exception e){e.printStackTrace ();} $FZ~]Ef  
} #Z)e]4{!l  
} %N7b XKDP  
fQ=Yf?b  
=LDzZ:' X  
//打印回应的头信息 d+rrb>-OU  
public void logResponseHead(HttpURLConnection con) !JzM<hyg3  
{ *r@7:a5  
for(int i=1;;i++) 5'd$TC  
{ ]@vX4G/  
String header=con.getHeaderFieldKey(i); $[T^ S  
if(header!=null) [-_3Zr  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "}!|V)K  
Utility.log(header+" : "+con.getHeaderField(header)); !'wh hi  
else z6]dF"N  
break; B\r2M`N5  
} jOa . h  
} .LhIB?  
E^rKS&P  
'FgBYy/  
public void splitterStop() @)1>ba  
{ R8I%Cyc  
bStop = true; L15?\|':Y  
} de1cl<  
f6vhW66:?x  
U(P^-J<n1  
} 1fm4:xHH  
yhv(KI  
a$r- U_?  
/* *`Swv`  
**FileAccess.java S[J eW  
*//文件访问(定位,写) z`$jxSLm  
package NetFox; (hNTr(z  
import java.io.*; `)%zk W  
<*EMcZ  
m0QE S  
public class FileAccessI implements Serializable{ G2qv)7{l2  
/4/'&tY  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 G%^jgr)  
RandomAccessFile oSavedFile; J|,Uu^7`  
long nPos; vz5x{W  
v e($l"T  
q\s"B.(G"  
public FileAccessI() throws IOException )Tjh  
{ 7irpD7P>  
this("",0); O+x"c3@Z)D  
} [As9&]Bv5  
'&hz *yk  
yN[aBYJx,M  
public FileAccessI(String sName,long nPos) throws IOException oCfO:7  
{ A,67)li3  
oSavedFile = new RandomAccessFile(sName,"rw"); ~_Q~AOFM  
this.nPos = nPos; 4> k"$l/:  
oSavedFile.seek(nPos); V=^B7a.;>  
} 4`yE'%6.}  
Y TpiOPf  
Z$ ?(~ln  
public synchronized int write(byte[] b,int nStart,int nLen) GDF/0-/Z  
{ Kzwbr?&z  
int n = -1; Kb X&E0  
try{ (4o<U%3kGq  
oSavedFile.write(b,nStart,nLen); V>Dqw!  
n = nLen; 'Qdea$o  
} Z(j"\d!y  
catch(IOException e) 7 Tb[sc'  
{ ]K?;XA3dZ  
e.printStackTrace (); e!W U  
} Tp46K\}Uf  
Gj_7wP$  
Q":,oZ2  
return n; j,n\`7dD$  
} >``sM=Wat  
ZnKjU ]m  
E5aRTDLq  
} x~Y{ {  
xU/7}='T  
|`ya+/ff+  
/* @An}  
**SiteInfoBean.java F f{,zfN+3  
*/ apOXcZ   
package NetFox; (> W \Nf  
cY5w,.Q/!  
2&"qNpPtE  
public class SiteInfoBean { .k:heN2-x  
8`<e\g7-  
NnH]c+  
private String sSiteURL; //Site's URL /#WvC;B  
private String sFilePath; //Saved File's Path T;G<62`.h  
private String sFileName; //Saved File's Name 6r|=^3{  
private int nSplitter; //Count of Splited Downloading File O 1D|T"@  
oXjoQ  
IRGcE&m  
public SiteInfoBean() FsO_|r  
{//nSplitter的缺省值为5 @ ]40xKF  
//default value of nSplitter is 5 @R-11wP)M  
this("","","",5); -Bl]RpHCe  
} &~Pk*A_:  
h@E7wp1'~  
<UF0Xc&X'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) zYrJ Hn#vB  
{ u^G Y7gah  
sSiteURL= sURL; O\CnKNk,  
sFilePath = sPath; hq&|   
sFileName = sName; (dZ]j){  
this.nSplitter = nSpiltter; pd B\D  
j+fib} 8}  
DK eB%k  
} hxzA1s%~  
"u]&~$  
%3O))Ug5  
public String getSSiteURL() ufCpX>lNF  
{ Vpne-PW  
return sSiteURL; GGnlkp& E  
} ?2l `%l5(  
 =n5n  
L2+cVR  
public void setSSiteURL(String value) 51JB,}dGH}  
{ I?S t}Tl  
sSiteURL = value; iGSA$U P|  
} u7^(?"x  
F)KR8 (  
7UY4* j|[C  
public String getSFilePath() =6qTz3t  
{  od{\z  
return sFilePath; VP>*J`'H  
} SkMFJ?J/  
]iGeqwT  
;}iB9 Tl  
public void setSFilePath(String value) yq49fEgc@U  
{ _XT'h;m  
sFilePath = value; O >pv/Ns  
} Db<#gH  
E(j# R"  
9sT5l"?g  
public String getSFileName() ]VxC]a2  
{ w6Nn x5Ay  
return sFileName; ,5"(m?[m  
} );':aX j  
|mE;HvQF  
njf\fw_  
public void setSFileName(String value) Vn4wk>b}$2  
{ ZaU8eg7  
sFileName = value; R?O)v Lmd  
} @U18Dj[  
7M~sol[*  
fCx (  
public int getNSplitter() sa4w.9O1GS  
{ dgF%&*Il]O  
return nSplitter; 5\MC5us3  
} g/JF(nkP  
jZzTnmm&?  
!CWe1Dm  
public void setNSplitter(int nCount) >i,_qe?V:w  
{ uD>=  
nSplitter = nCount; ,JE_aje7  
} UMR?q0J  
} k_L`  
d]] z )  
)^ Y+Vn  
/* )rK2%\Z  
**Utility.java Ha`N  
*/ }I&.xzJ  
package NetFox; +Cw_qS"=  
WHY/x /$  
:.,9}\LK  
public class Utility { P[ WkW#  
3$nK   
>MHlrSH2  
public Utility() h6 {vbYj  
{ 5, 1<A@H  
}yEV&& @  
t1adS:)s  
} e~SK*vR%]  
n"Ie>  
//线程睡眠 ^ ~Eh+  
public static void sleep(int nSecond) TC?B_;a  
{ [j+:2@  
try{ Reikf}9Q  
Thread.sleep(nSecond); HeAXZA,  
} ;7lON-@BI  
catch(Exception e) ;o!p9MEpz;  
{ X ."z+-eh  
e.printStackTrace (); F3}MM dX  
} }tW-l*\U  
} hy*{ {f;  
^HSxE  
//日志  vmqa_gU\  
public static void log(String sMsg) 4k;FZo]S  
{ NUFz'MPv  
System.err.println(sMsg); &:&89<C'  
} u#@/^h;  
 VGV-t  
a;HAuy`M x  
public static void log(int sMsg) r)iEtT!p*  
{ *): |WDR  
System.err.println(sMsg); ~=|}!A(  
} *,\"}x*  
} o&?c,FwN  
1INX#qTZ  
E=s,-  
/* f$o^Xu  
**TestMethod.java +~^S'6yB  
*/ QH/py  
package NetFox; }iUK`e  
ra$:ibLN  
]@&X*~c^Z  
public class TestMethod { C}8#yAS9M  
QtW9!p7(  
E\[BE<y  
public TestMethod() y(COB6r  
{ ///xx/weblogic60b2_win.exe d51lTGH7Z  
try{ pDR~SxBXr  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3V k8'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *2/Jg'de  
SiteFileFetch fileFetch = new SiteFileFetch(bean); X0.H(p#s  
fileFetch.start(); Xh@K89`uX  
} NHd@s#@  
catch(Exception e){e.printStackTrace ();} o :d7IL  
cbJgeif  
vzIo2 ,/7  
} F!vrvlD`s  
t+?Bb7p,H  
gu k,GF9p]  
public static void main(String[] args) ?2<) Jw  
{ @;/Pl>$|'G  
new TestMethod(); % N8I'*u  
} Bz]tKJ  
} WcN4ff-  
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