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http断点续传简单实现(java)

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/* c/=\YeR  
**SiteFileFetch.java B/mfm 7  
*/ ~0o>B$xJ  
package NetFox; IFZw54  
import java.io.*; ~$rSy|19  
import java.net.*; mVN\  
(dy:d^  
<]_[o:nOP  
public class SiteFileFetch extends Thread { ^rO!-  
}[PC YnS  
7AqbfLO  
SiteInfoBean siteInfoBean = null; //文件信息Bean z5D*UOy5M  
long[] nStartPos; //开始位置 C[l5[DpH  
long[] nEndPos; //结束位置 pB]*cd B?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %sPq*w.  
long nFileLength; //文件长度 $Y\7E/T  
boolean bFirst = true; //是否第一次取文件 YN7O Qqa  
boolean bStop = false; //停止标志 cBU3Q<^  
File tmpFile; //文件下载的临时信息 hBifn\dFr  
DataOutputStream output; //输出到文件的输出流 'c]Pm,Ls  
9l|*E  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ,|;\)tT  
public SiteFileFetch(SiteInfoBean bean) throws IOException JuOCOl\  
{ S\GxLW@x  
siteInfoBean = bean; k'sPA_|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _EP~PW#J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); T.B7QAI. H  
if(tmpFile.exists ()) wbk$(P'gN  
{ ytb1hFs  
bFirst = false; S)'&+HamI  
read_nPos(); *+00  
} oMYZ^b^  
else OHnsfXO_V  
{ glkH??S  
nStartPos = new long[bean.getNSplitter()]; 7j(gW  
nEndPos = new long[bean.getNSplitter()]; aZ|S$-}  
} W[e2J&G  
bweAmSs  
h&!$ `)   
^&c &5S}  
} !t{  
JW=q'ibR  
pX$ X8z%  
public void run() "`4M4`'  
{ ,% .)mf  
//获得文件长度 v`Ja Bn  
//分割文件 [A] +Azc  
//实例FileSplitterFetch t1$pl6&,  
//启动FileSplitterFetch线程 I*g[Y=  
//等待子线程返回 NSR][h_  
try{ #BgiDLh  
if(bFirst) +CXq41g"c  
{  H =&K_  
nFileLength = getFileSize(); V^>< =DNE  
if(nFileLength == -1) Hq?dqg'%~  
{ g:6 `1C  
System.err.println("File Length is not known!"); HV]u9nrt#  
} u?>8`]r  
else if(nFileLength == -2) xK5~9StP  
{ 7xO~v23oe  
System.err.println("File is not access!"); )YZx]6\l)  
} n;:C{5  
else =rkW325O  
{ u_8Z^T  
for(int i=0;i<nStartPos.length;i++) myd:"u,}9  
{ nyOmNvZf  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); PeLzZ'$D  
} Gq%,'am f  
for(int i=0;i<nEndPos.length-1;i++) N0ef5J JM`  
{ FJ{&R Ld  
nEndPos = nStartPos[i+1]; hx4c`fOs  
} I SdB5Va  
nEndPos[nEndPos.length-1] = nFileLength; Im]6-#(9\|  
} @~&^1%37)  
} EN8xn9M?  
D^U?!S&4~  
fhC|=0XB  
//启动子线程 >McEuoZx9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5dbj{r)s6i  
for(int i=0;i<nStartPos.length;i++) ov >5+"q)  
{ K(P.i^k  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w02C1oGfx  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^oClf(  
nStartPos,nEndPos,i); @Q&k6.{4Z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H7meI9L  
fileSplitterFetch.start(); a6;5mx  
} &^Gp  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C<w&mFozL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); cJM.Q_I}Y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,e GF~  
nEndPos = " + nFileLength); .*J /F$  
// fileSplitterFetch[nPos.length-1].start(); PR,8c  
VtGZB3  
%u2",eHCB  
//等待子线程结束 4[Wwm  
//int count = 0; $H&:R&Us  
//是否结束while循环 eF' l_*  
boolean breakWhile = false; g yT0h?xDt  
;Sp/N4+  
Z.s0ddM s  
while(!bStop) (CJx Y(1K  
{ A5_r(Z-5  
write_nPos(); o*oFCR]j  
Utility.sleep(500); .kgt? r  
breakWhile = true; 9w=[}<E  
k]2_vk^  
MN:LL <  
for(int i=0;i<nStartPos.length;i++) E Q:6R|L  
{ |=V~CQ]  
if(!fileSplitterFetch.bDownOver) rD9:4W`^  
{ |.- Muv  
breakWhile = false; vskp1Wi(  
break; 8`90a\t'Z  
} zw iS%-F  
} <|w(Sn  
if(breakWhile) q0NToVo@  
break; *9EW &Ek  
"98 j-L=F+  
x+DecO2  
//count++; cIrc@  
//if(count>4) k~fH:X~x  
// siteStop(); k dhwnO  
} |t~>Xs  
wti  
>5D;uTy u  
System.err.println("文件下载结束!"); 2(Aw  
} GR_caP  
catch(Exception e){e.printStackTrace ();} n9-WZsc1  
} vF/wV'Kk  
e0<O6  
$R:Q R?   
//获得文件长度 vUDMl Z  
public long getFileSize() S6fbwZZMG  
{ o7eWL/1  
int nFileLength = -1; D'BGoVP  
try{ 6& 6|R3  
URL url = new URL(siteInfoBean.getSSiteURL()); o^r\7g6\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v2="j  
httpConnection.setRequestProperty("User-Agent","NetFox"); ) t CNp  
g${k8.TV  
{i}E)Np  
int responseCode=httpConnection.getResponseCode(); k+Z2)j"  
if(responseCode>=400) [khXAf1{Q  
{ zJ@^Bw;A^@  
processErrorCode(responseCode); ntW1 )H'o  
return -2; //-2 represent access is error S,Tc\}  
} QZ*gR#K]Sz  
[ugr<[6  
MV07RjeS  
String sHeader; -=ZDfM  
q;7DH4;t  
k|U2Mp  
for(int i=1;;i++) H6U 5-  
{ DKkilqVM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); OB*V4Yv  
//Utility.log(in.readLine()); {<?8Y  
sHeader=httpConnection.getHeaderFieldKey(i); $dA]GWW5A  
if(sHeader!=null) ]b:>7_la  
{ 9Hd_sNUu\  
if(sHeader.equals("Content-Length")) ExeZj8U  
{ E=`/}2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c5: X$k\  
break; 9PMIF9"   
} |--Jd$ dj  
} ''3I0X*!  
else q%dbx:y#  
break; ?-)v{4{s  
} [1O{yPV3s  
} X; 6=WqJj  
catch(IOException e){e.printStackTrace ();} ,i8%qm8  
catch(Exception e){e.printStackTrace ();} ;~'&m  
vhcp[=e :  
6Rmdf>a  
Utility.log(nFileLength); Rz[3cN)?q  
(NN;1{DB8  
RgZ9ZrE\  
return nFileLength; S5d  
} \f)GW$`  
%$i}[ U  
W+$G{XSr5C  
//保存下载信息(文件指针位置) ? Dn}  
private void write_nPos() l@ (:Q!Sk  
{ TwI'XMO;A  
try{  qI${7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); g4952u  
output.writeInt(nStartPos.length); j-.Y!$a%6  
for(int i=0;i<nStartPos.length;i++) 5pK _-:?  
{ +T8MQ[(4  
// output.writeLong(nPos); 8@RtL,[d  
output.writeLong(fileSplitterFetch.nStartPos); (.VS&Kv#U  
output.writeLong(fileSplitterFetch.nEndPos); S4'<kF0z  
} *[|+5LVn  
output.close(); }W&9}9p"  
} {8oGWQgrj  
catch(IOException e){e.printStackTrace ();} +C[g>c}d  
catch(Exception e){e.printStackTrace ();} 1ANb=X|hig  
} b6p'%;Y/  
$2RSYI`py  
lW|v_oP9  
//读取保存的下载信息(文件指针位置) Aa4Tq2G  
private void read_nPos() ,>8w|951'  
{ )^+hm+27v  
try{ e<[ ] W4"A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;_2+Y^Qb  
int nCount = input.readInt(); N_Kdi%q  
nStartPos = new long[nCount]; Vzo< ma^  
nEndPos = new long[nCount]; ;BYuNQr  
for(int i=0;i<nStartPos.length;i++) ra>2<  
{ -e sQyLx  
nStartPos = input.readLong(); -6~.;M 5  
nEndPos = input.readLong(); P;mp)1C  
} =0!j"z=  
input.close(); RZ;s_16GQ  
} V; CPn  
catch(IOException e){e.printStackTrace ();} S!+>{JyQ  
catch(Exception e){e.printStackTrace ();} y@I t#!u0  
} 7 nFOV Z  
/ *PHX@  
 bLAHVi<.  
private void processErrorCode(int nErrorCode) 'tvuw\hhL  
{ ,?k1if(0[  
System.err.println("Error Code : " + nErrorCode); ,v,rY'  
} _53~D=  
mt`CQz"_  
RHMXPsj  
//停止文件下载 RjVmHhX  
public void siteStop() |_>^vW1f  
{ q=V'pML  
bStop = true; x!\q69ndv  
for(int i=0;i<nStartPos.length;i++) ~BX=n9  
fileSplitterFetch.splitterStop(); [/%N2mj  
e}S+1G6r)  
75lh07  
} ^gZ,A]  
} d7 H*F  
//负责部分文件的抓取 TlRc8r|  
**FileSplitterFetch.java ^|]Dg &N.  
*/ ~x#TfeU]  
package NetFox; x3Y)l1gh  
b*M?\ aA  
nP]!{J]  
import java.io.*; q$mc{F($D  
import java.net.*; ]z/R?SM  
"\KBF  
G3%Ju=  
public class FileSplitterFetch extends Thread { =I)43ah d  
~~ rR< re  
!hhL",  
String sURL; //File URL j)6p>6  
long nStartPos; //File Snippet Start Position yxo=eSOM  
long nEndPos; //File Snippet End Position m<#12#D  
int nThreadID; //Thread's ID 5<R m{  
boolean bDownOver = false; //Downing is over ;%B9mM#p~  
boolean bStop = false; //Stop identical V?1 $H  
FileAccessI fileAccessI = null; //File Access interface  1/2cb-V  
Z>Mv$F"p:  
cgSN:$p(R  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <7`zc7c]#  
{ <.B+&3')  
this.sURL = sURL; $[n:IDa*@1  
this.nStartPos = nStart; }$4z$&  
this.nEndPos = nEnd; >[,eK=  
nThreadID = id; ?'9IgT[*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~~Ezt*lH  
} yi>A ogQ,  
.  yg#  
f$ xp74hw3  
public void run() d6YXITL)\>  
{ U/QgO  
while(nStartPos < nEndPos && !bStop) |#kY_d)10  
{ m(6d3P  
a[(OeVQ5  
qul#)HI  
try{ dkZe.pv$j  
URL url = new URL(sURL); ;54NQB3L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  pUb1#=  
httpConnection.setRequestProperty("User-Agent","NetFox"); g-~ _gt7  
String sProperty = "bytes="+nStartPos+"-"; (^m] 7l  
httpConnection.setRequestProperty("RANGE",sProperty); 0f.j W O  
Utility.log(sProperty); <ak[`]  
2 HEU  
dD=$$( je  
InputStream input = httpConnection.getInputStream(); ?<TJ}("/  
//logResponseHead(httpConnection); 49$<:{~  
7upko9d/  
h @!p:]  
byte[] b = new byte[1024]; hx$61 E=  
int nRead; 7GYf#} N  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :^v Q4/,  
{ C,Nf|L((6  
nStartPos += fileAccessI.write(b,0,nRead); %+N]$Q  
//if(nThreadID == 1) Pc`d]*BYi  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )Y7H@e\1  
} VAz4@r7hkq  
ApXf<MAy  
'z(Y9%+a  
Utility.log("Thread " + nThreadID + " is over!"); Pwl*5/l  
bDownOver = true; '|[V}K5m/f  
//nPos = fileAccessI.write (b,0,nRead); q"u,Tnc;  
} A iM ukd,  
catch(Exception e){e.printStackTrace ();} yx :^*/  
} fY[Fwjj3  
} 1^![8>u"  
"w'pIUQ3,  
HcsV q+  
//打印回应的头信息 j|k/&q[St  
public void logResponseHead(HttpURLConnection con) s)a-ky(  
{ 6]?mjG6  
for(int i=1;;i++) 3' i6<  
{ E1eGZ&&Gd  
String header=con.getHeaderFieldKey(i); CO='[1"_5  
if(header!=null) EfrQ~`\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ayy\7b  
Utility.log(header+" : "+con.getHeaderField(header)); ?e$&=FC0;  
else g X!>ef  
break; x#D%3v"l_*  
} p"ZvA^d\   
} K381B5_h  
-e/}DGL  
!C#oZU]P  
public void splitterStop() f+cb83}n]  
{ QxYm3x5  
bStop = true; |Vx [  
} +'<P W+U$  
.gx^L=O:  
da7"Q{f+  
} mqZH<.mn  
hCcI]#S&  
/iU<\+ H  
/* TTz=*t+D  
**FileAccess.java ]y_ :+SHc  
*//文件访问(定位,写) @7twe;07r  
package NetFox; -tj#BEC[H(  
import java.io.*; k$3pmy*  
JU?;Kq9R  
!9;m~T7.  
public class FileAccessI implements Serializable{ ba|xf@=&  
,8@<sF B'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d`^3fr'.4A  
RandomAccessFile oSavedFile; o08WC'bX  
long nPos; |g&V? lI  
Lv%3 jj  
8;@y\0  
public FileAccessI() throws IOException >n"0>[:4  
{ Nn LK!Q  
this("",0); [ohLG_9  
} FS1\`#Bm)  
r%U6,7d=)  
{r_HcI(h  
public FileAccessI(String sName,long nPos) throws IOException r mX*s} B  
{ Hd~g\  
oSavedFile = new RandomAccessFile(sName,"rw"); /mkT7,]  
this.nPos = nPos; a{kJ`fK   
oSavedFile.seek(nPos); wpK1nA+7N  
} ,1sbY!&ekL  
?^Rp" H   
e )0 ]WJ  
public synchronized int write(byte[] b,int nStart,int nLen) & FhJ%JK  
{ t1w5U+z  
int n = -1; zZCl]cql  
try{ q\EYsN</;  
oSavedFile.write(b,nStart,nLen); Cn~VJ,l g  
n = nLen; 4 Ej->T.  
} TKB8%/_p  
catch(IOException e) n _K1%  
{ d{S'6*`D  
e.printStackTrace (); c4fH/-  
} YV.' L  
*yhA8fJ  
Z@zo~*o  
return n; v"k ? e  
} ^*ZaqMA  
xX<f4H\'  
"\o#YC  
} w6vbYPCN  
KuJ)alD;1  
}4C_r'd6  
/* 1-y8Hy_a2  
**SiteInfoBean.java <=.6Z*x+  
*/ <2pp6je\0s  
package NetFox; 6Z_V,LD9L  
a|t~&\@  
 /a1uG]Mt  
public class SiteInfoBean { w%])  
RTmp$lV  
NXOXN]=c<  
private String sSiteURL; //Site's URL %~Yo{4mHs  
private String sFilePath; //Saved File's Path ;Nn(  
private String sFileName; //Saved File's Name v9f+ {Y%-  
private int nSplitter; //Count of Splited Downloading File jEBn"]\D  
oMbd1uus  
:s *  
public SiteInfoBean() |5~Oh`w  
{//nSplitter的缺省值为5 ~J].~^[  
//default value of nSplitter is 5 #*iUZo  
this("","","",5); ~0PzRS^o  
} >$m<R &  
VIF43/>(  
U"Gx Xrl  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p<L7qwOii  
{ B?j t?  
sSiteURL= sURL; /|v4]t-  
sFilePath = sPath; ]9YA~n\  
sFileName = sName; u> {aF{  
this.nSplitter = nSpiltter; 'yiv.<4  
D6VdgU|  
SJiQg-+<Uf  
} rj=as>6B  
edL2ax  
Ze0qRLuH!  
public String getSSiteURL() v2x+_K}J  
{ }b1G21Dc!  
return sSiteURL; !>9s  
} pT,8E(*l2  
9nAP%MA`  
NJBSVC b  
public void setSSiteURL(String value) irlFB#..  
{ n-9xfn0U~#  
sSiteURL = value; XM\\Imw  
} V lx.C~WYn  
}TTghE!  
6_`Bo%  
public String getSFilePath() f/Y&)#g>k  
{ zmhc\M ?z  
return sFilePath; &{j!!LL  
} ?M:>2wl  
eA& #33  
9^/Y7Wp/@  
public void setSFilePath(String value) `KZV@t  
{ N:lE{IvRJ  
sFilePath = value; ,V1"Typ#<  
} _<Ak M"  
b+~_/;Y9  
6Q:Wo)^!  
public String getSFileName() q(n"r0)=  
{ `NtW+v  
return sFileName; vEI{AmogRx  
} c0o]O[  
.=eEuH  
zQ+Mu^|u+  
public void setSFileName(String value) $NR[U+  
{ /l<(i+0  
sFileName = value; HO<|EH~lu  
} |Ahf 01  
;a?<7LIx  
6 /<Hx@r (  
public int getNSplitter() k^cZePqE6d  
{ L-(bw3Yr>  
return nSplitter; gY7sf1\wX  
} EK# 11@0%  
Phi5;U!  
QD7KE6KP'  
public void setNSplitter(int nCount) =DdPwr 0Op  
{ Rrh6-]A  
nSplitter = nCount; 4bk`i*-O  
} "s|P,*Xf  
} K+)3 LR^  
6,5h4[eF*  
o}Grb/LJ  
/* 8y27O  
**Utility.java 'xta/@Sq  
*/ aV$kxzEc  
package NetFox; brmS J7  
t"B3?<?]  
8-@@QZ\N  
public class Utility { YC1Bgz  
\Vme\Ke*v)  
+q pW"0[  
public Utility() ymm]+v5S.]  
{ dU9;sx  
_&]7  
6 rnFXZ\  
} Md4Q.8  
GTLS0l)  
//线程睡眠 '1D $ ;  
public static void sleep(int nSecond) 1 3 ]e< '  
{ *IOrv)  
try{ |? V7E\S  
Thread.sleep(nSecond); W(]A^C=/  
} LM eI[Ji  
catch(Exception e) ^mL X}E]  
{ rCF=m]1zxT  
e.printStackTrace (); g)6>=Qo`8E  
} (2eS:1+'8  
} Z7bJ<TpZ  
?wHhBh-Q  
//日志 85!]N F  
public static void log(String sMsg) 7RDmvWd-'?  
{ H{n:R *  
System.err.println(sMsg); CzG[S\{+  
} jOT/|k  
Stw g[K0<  
R[zN?  
public static void log(int sMsg) ueJ^Q,-t  
{ Ug+ K:YUq  
System.err.println(sMsg); cD]H~D}M  
} DY#195H  
} w4P;Z-Cd  
I8! .n  
GZi`jp  
/* ?lkB{-%rQ  
**TestMethod.java @2T8H  
*/ }vh <x6  
package NetFox; _FOIMjh%N  
d:hnb)I$*  
.#~!w!T  
public class TestMethod { 8XYxyOl  
"*HM8\  
:|9vMM^$  
public TestMethod() 2->Lz  
{ ///xx/weblogic60b2_win.exe SZTn=\  
try{  p0W<K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]A}ZaXd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); '4M{Xn}@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); m!KEK\5M?  
fileFetch.start(); Je|:\Qk  
} 1qR$ Yr\  
catch(Exception e){e.printStackTrace ();} v)np.j0V7  
E G+/2o+W  
&OJ?Za@p@)  
} hY!ek;/Gc  
6~sU[thGW  
M @KQOAzt  
public static void main(String[] args) l@&-be  
{ 0S :&wb  
new TestMethod(); ,y'6vW`%g9  
} YCE *Dm  
} $VQ;y|K+[  
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