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http断点续传简单实现(java)

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/* u4j5w  
**SiteFileFetch.java }M+7 T\ J!  
*/ M?qy(zb  
package NetFox; $u.z*b_yy  
import java.io.*; D]}G.v1  
import java.net.*; Yz bXuJ4  
"]dI1 g_  
z:;CX@)*  
public class SiteFileFetch extends Thread { ,s(,S  
8_8l.!~  
nR~(0G,H  
SiteInfoBean siteInfoBean = null; //文件信息Bean nK,w]{<wG!  
long[] nStartPos; //开始位置 hQ i2U  
long[] nEndPos; //结束位置 KSvE~h[#+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9iq_rd]  
long nFileLength; //文件长度 o@Oqm>]SS  
boolean bFirst = true; //是否第一次取文件 nlYNN/@"  
boolean bStop = false; //停止标志 OCUr{Nh  
File tmpFile; //文件下载的临时信息 kl`W\tF  
DataOutputStream output; //输出到文件的输出流 HhpDR  
G?ZXWu.  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ;fJ.8C  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8RX&k  
{ 2?5>o!C  
siteInfoBean = bean; q@qsp&0/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /ouPg=+Nl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e!Hhs/&!T  
if(tmpFile.exists ()) _^;Z~/.  
{ : 'c&,oLY  
bFirst = false; xmG<]WF>E  
read_nPos(); G#CXs:1pd+  
} liZxBs :%i  
else hj:,S |  
{ *Uh!>Iv;  
nStartPos = new long[bean.getNSplitter()]; RpK@?[4s  
nEndPos = new long[bean.getNSplitter()]; g*Phv|kI  
} '7/)Ot(  
B6"0OIDY"  
_+,TT['57s  
`gJ(0#ac  
} Gq6*SaTk  
TJN4k@\$2  
Si7*& dw=  
public void run() aYeR{Y]  
{ JLYi]nZ  
//获得文件长度 %RVZD#zr  
//分割文件 y(&Ac[foS}  
//实例FileSplitterFetch 6mE\OS-I  
//启动FileSplitterFetch线程 y2v^-q3  
//等待子线程返回 iwq!w6+  
try{ F:VIzyMq<  
if(bFirst) GeqPRah  
{ :Al!1BJQ  
nFileLength = getFileSize(); ;j7#7MN2_E  
if(nFileLength == -1) dI2 V>vk  
{ y9;Yiv r)  
System.err.println("File Length is not known!"); =vPj%oLp'a  
} lk!@?  
else if(nFileLength == -2) s.#`&Sd>  
{ z{6Z 11|  
System.err.println("File is not access!"); l.]xB,k  
} FlQGg VN  
else @c#(.=  
{ >usL*b0%  
for(int i=0;i<nStartPos.length;i++) =v\.h=~~  
{ ':q p05t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,I9bNO,%JK  
} BWNi [^]  
for(int i=0;i<nEndPos.length-1;i++) lFk R=!?=  
{ 7,MR*TO,  
nEndPos = nStartPos[i+1]; s*4dxnS_8  
} \^LFkp  
nEndPos[nEndPos.length-1] = nFileLength; <$YlH@;)`a  
} vIvIfE  
} "N;EL0=  
=*Lfl'sr_  
*hrvYil2b  
//启动子线程 teP<!RKNb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t7pFW^&  
for(int i=0;i<nStartPos.length;i++) jo7\`#(Q  
{ t:S+%u U  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LP-o8c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =AT."$r>  
nStartPos,nEndPos,i); So6x"1B  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IgzQr >  
fileSplitterFetch.start(); 3R/bz0 V>  
} Zfw,7am/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *Ly6`HZ9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5(2;|I,T  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", F{wzB  
nEndPos = " + nFileLength); y} '@R$  
// fileSplitterFetch[nPos.length-1].start(); l}h!B_P'  
DDZ@$L!  
0]L"H<W  
//等待子线程结束 m'U0'}Ld};  
//int count = 0; N+|d3X!  
//是否结束while循环 m~|40)   
boolean breakWhile = false; ;"I^ZFYX  
54,er$$V  
?0.NIu,,o  
while(!bStop) ^OdP4m( >>  
{ =wJX 0A|  
write_nPos(); K"6vXv4QO  
Utility.sleep(500); iscz}E,Y  
breakWhile = true; `V1]k_h  
sA~]$A;DM!  
mq l Z?-  
for(int i=0;i<nStartPos.length;i++) Ef\ -VKh  
{ hP h-+Hb  
if(!fileSplitterFetch.bDownOver) s~>}a  
{ r%_djUd  
breakWhile = false; U:`Kss`  
break; =I<R!ZSN  
} aXVFc5C\  
} Qrv<lE1V;  
if(breakWhile) t1".0  
break; baasGa3}s  
kstIgcI  
b>|6t~}M  
//count++; W^Yxny  
//if(count>4) l} /F*  
// siteStop(); hxx.9x>ow  
} K9[UB  
H}!r|nG  
' QG?nu  
System.err.println("文件下载结束!"); 7pd$\$  
} txpgO1  
catch(Exception e){e.printStackTrace ();} K'bP@y_cq  
} Z;i:](  
Dv"9qk  
;gkM{={`p  
//获得文件长度 ZNoDFf*h  
public long getFileSize() 'F<TSy|4kI  
{ QZs!{sZ  
int nFileLength = -1; 4Ig;3 ^%71  
try{ 7/H)Az@i45  
URL url = new URL(siteInfoBean.getSSiteURL()); :h$$J lP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _w{Qtj~s|  
httpConnection.setRequestProperty("User-Agent","NetFox"); !VJoM,b8  
Wzh`or  
1x)J[fyId  
int responseCode=httpConnection.getResponseCode(); .8R@2c`}Cs  
if(responseCode>=400) D- c4EV  
{ PsYpxNr  
processErrorCode(responseCode); 9p/Bh$vJ  
return -2; //-2 represent access is error 2iOV/=+  
} Z r8*et  
3mgD(,(^  
>%G1"d?j  
String sHeader; H)?z #x  
h\o.&6sd  
j^'go&p  
for(int i=1;;i++) 8Wx=p#_  
{ %;_MGae  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); UpG~[u)%@  
//Utility.log(in.readLine()); :]KAkhFkbb  
sHeader=httpConnection.getHeaderFieldKey(i); L#J1b!D&<6  
if(sHeader!=null) fl(wV.Je|  
{ \Z/@C lCm  
if(sHeader.equals("Content-Length")) s#11FfF`  
{ o4X{L`m  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Wc#24:OKe3  
break; +2{Lh7Ks  
} JI}'dU>*U:  
} 3$ pX  
else u[YGm:}  
break; L_T5nD^D  
}  )2.Si#  
} UfGkTwoo=  
catch(IOException e){e.printStackTrace ();} 29Ki uP  
catch(Exception e){e.printStackTrace ();} wj,=$RX  
+whDU2 "  
q 1,~  
Utility.log(nFileLength); <YY14p  
#a6iuO0I  
$mILoy B,  
return nFileLength; !zo{tI19  
} ! mHO$bQ"  
CrLrw T  
3S{ />1Y  
//保存下载信息(文件指针位置) GJrG~T  
private void write_nPos() C_Dn{  
{ ;+%rw2Z,B  
try{ r&CiSMS*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); t0S 1QC+  
output.writeInt(nStartPos.length); Cy e.gsCT  
for(int i=0;i<nStartPos.length;i++) z_HdISy0  
{ /x hKd]Q  
// output.writeLong(nPos); d6O[ @CyP  
output.writeLong(fileSplitterFetch.nStartPos); L,\Iasv  
output.writeLong(fileSplitterFetch.nEndPos); \hXDO_U  
} KoT\pY^7\  
output.close(); { FkF  
} ^W ^OfY  
catch(IOException e){e.printStackTrace ();} @dK Tx#gZ  
catch(Exception e){e.printStackTrace ();} 7I}uZ/N  
} Y]>t[Lo%  
hb$Ce'}N  
7dWS  
//读取保存的下载信息(文件指针位置) ,bi^P>X  
private void read_nPos() P0@,fd<  
{ TbU#96"~.  
try{ 4 KiY6)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (=0.inZ  
int nCount = input.readInt(); ~$'awY  
nStartPos = new long[nCount]; By |4 m  
nEndPos = new long[nCount]; .Mbz3;i0  
for(int i=0;i<nStartPos.length;i++) ]gOy(\B  
{ COlqcq'qAu  
nStartPos = input.readLong(); *@5@,=d  
nEndPos = input.readLong(); 9;{C IMg&  
} <I?Zk80  
input.close(); -RwE%  cr  
} fC`&g~yK'  
catch(IOException e){e.printStackTrace ();} c{|p.hd  
catch(Exception e){e.printStackTrace ();} $FVNCFN%  
} ]^E?;1$f?  
la!~\wpa  
_>+Ld6.T6  
private void processErrorCode(int nErrorCode) lxx2H1([  
{ RZLq]8pM  
System.err.println("Error Code : " + nErrorCode); 3fj4%P"  
} MtdG>TzUn  
^q5#ihM  
?s01@f#  
//停止文件下载 Hl"N}   
public void siteStop() #mdc[.  
{ u 9e@a9c  
bStop = true; K+eM   
for(int i=0;i<nStartPos.length;i++) x5Bk/e'  
fileSplitterFetch.splitterStop(); SUiOJ[5,  
>:-$+I  
oJ^P(]dw  
} X ?O[r3<  
} oA 1yIp  
//负责部分文件的抓取 y[;>#j$  
**FileSplitterFetch.java l?e.9o2-  
*/ WWY6ha  
package NetFox; r!v\"6:OM  
D.:Zx  
4hB]vY\T  
import java.io.*; j2k"cmsKh  
import java.net.*; y29m/i:  
IGl9 g_18  
-?\D\\+t  
public class FileSplitterFetch extends Thread { @ArSC  
Jy)/%p~  
O.? JmE  
String sURL; //File URL F9PxSk_\9  
long nStartPos; //File Snippet Start Position V~GDPJ+  
long nEndPos; //File Snippet End Position /~1+i'7V.,  
int nThreadID; //Thread's ID llq<egZpm  
boolean bDownOver = false; //Downing is over dysS9a,  
boolean bStop = false; //Stop identical "oyo#-5z  
FileAccessI fileAccessI = null; //File Access interface &ZO0r ^  
_a, s )  
F?0Ykjh3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException OUnA;_  
{ pa+hL,w{6  
this.sURL = sURL; :OT&  
this.nStartPos = nStart; M\j.8jG  
this.nEndPos = nEnd; E .h*g8bXe  
nThreadID = id; 0GwR~Z}Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 43cE`9~  
} ).O)p9  
KNl$3nX  
0GLM(JmK  
public void run() "]*tLL:`  
{ 0-gAyiKx?  
while(nStartPos < nEndPos && !bStop) @7 }W=HB  
{ >P(.:_ ^p  
X w1*(ffk  
*~`(RV  
try{ h[ ZN+M  
URL url = new URL(sURL); i8p6Xht  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jXJyc'm7  
httpConnection.setRequestProperty("User-Agent","NetFox"); !WlH'y-I  
String sProperty = "bytes="+nStartPos+"-"; WH\d| 1)  
httpConnection.setRequestProperty("RANGE",sProperty); kZ~~/?B  
Utility.log(sProperty); 9r9NxKuAO  
9c],<;{'  
637: oT_`O  
InputStream input = httpConnection.getInputStream(); ceA9) {  
//logResponseHead(httpConnection); }V>T M{  
U$g?!Yl0  
crCJrN=  
byte[] b = new byte[1024]; \8tsDG(1 '  
int nRead; H,J8M{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) l;U?Z'n  
{ tPvpJX6kP  
nStartPos += fileAccessI.write(b,0,nRead); "@kaHIf[  
//if(nThreadID == 1) f$( e\+ +  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3`HV(5U[  
} gw(z1L5 n  
K3C<{#r  
kfNWI#'9  
Utility.log("Thread " + nThreadID + " is over!"); f1? >h\F8  
bDownOver = true; WIOV2+  
//nPos = fileAccessI.write (b,0,nRead); ICCc./l|  
} M5B# TAybC  
catch(Exception e){e.printStackTrace ();} KoYF]  
} pAEx#ck  
} ~[: 2I  
t^HRgY'NjM  
s2?&!  
//打印回应的头信息 L];b< *d  
public void logResponseHead(HttpURLConnection con) Ac6=(B  
{ |ZBw<f  
for(int i=1;;i++) *:1ey{w:  
{ y(Td/rY.  
String header=con.getHeaderFieldKey(i); 9uY'E'm*  
if(header!=null) <3iMRe  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 13PS2  
Utility.log(header+" : "+con.getHeaderField(header)); k9R9Nz|J  
else a.'*G6~Qgw  
break; ^.tg7%dJ  
} GILfbNcd  
} qR.Q,(b|  
N!32 wJ  
^8tEach  
public void splitterStop() C~[,z.FvO  
{ lr?;*f^3  
bStop = true; SuznN L=/$  
} Cw%{G'O   
c,22*.V/  
zi:BF60]=  
} ax2B ]L2  
]Dzlp7Y}  
=sFTxd_"iQ  
/* mmsPLv6  
**FileAccess.java wBzC5T%,  
*//文件访问(定位,写) ]9L oZ)  
package NetFox; fVwU e _Y  
import java.io.*; f::Dx1VcX  
'yth'[  
j|n R "!  
public class FileAccessI implements Serializable{  OSJ$d  
U.TA^S]`g  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Al'3?  
RandomAccessFile oSavedFile; ZuIefMiG~+  
long nPos; uEY tE7  
\9d$@V  
u>$t'  
public FileAccessI() throws IOException X 8|EHb<  
{ xPgBV~  
this("",0); "L1Zi.)  
} d3Rw!slIq  
':W[A  
HDKbF/  
public FileAccessI(String sName,long nPos) throws IOException tDo"K3   
{ fnY.ao1-s[  
oSavedFile = new RandomAccessFile(sName,"rw"); +#By*;BJ  
this.nPos = nPos; 8Y3I0S  
oSavedFile.seek(nPos); y]im Z4{/  
} SaCh 7 ^  
:EH=_"  
/bEAK-  
public synchronized int write(byte[] b,int nStart,int nLen) G:JR7N$  
{ k8Xm n6X  
int n = -1; 1cGmg1U;  
try{ :LTN!jj  
oSavedFile.write(b,nStart,nLen); nm+s{  
n = nLen; 9cgU T@a  
} zJXplvaL;  
catch(IOException e) C>~TI,5a3  
{ />Nt[o[r  
e.printStackTrace (); s(^mZ -i  
} R4@6G&2d>  
KgG4*<  
':}\4j&{E  
return n; 2Hdu:"j  
} ]d`VT)~vje  
!+njS  
DJ%PWlK5  
} |'.  
&?vgP!d&M  
kl,3IKHa  
/* s7EinI{^  
**SiteInfoBean.java L(o15  
*/ e*!kZAf  
package NetFox; V,9cl,z+  
3[&Cg  
.G^YqJ 4  
public class SiteInfoBean { h1{3njdr  
~v83pu1!2s  
kR9-8I{J  
private String sSiteURL; //Site's URL 0Qd:`HF[  
private String sFilePath; //Saved File's Path Jl<2>@  
private String sFileName; //Saved File's Name lLD12d  
private int nSplitter; //Count of Splited Downloading File Z= !*e~j@  
875od  
V$~9]*Wn  
public SiteInfoBean() 3~ \[7I/  
{//nSplitter的缺省值为5 d\Zng!Z'  
//default value of nSplitter is 5 &0f,~ /%Z  
this("","","",5); dTtSUA|V7"  
} 2JFpZU"1  
2-b6gc7  
&OBkevg  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MW{8VH6+  
{ T>GM%^h,7-  
sSiteURL= sURL; XUw/2"D'?  
sFilePath = sPath; 4OX^(  
sFileName = sName; _ J[  
this.nSplitter = nSpiltter; #[a*rD%m  
fzA9'i`  
{iLT/i%  
} s{" 2L{,$  
VD:/PL  
X7 w Ky(g  
public String getSSiteURL() O~QB!<Q+  
{ `XB 9Mi=  
return sSiteURL; 05k0n E  
} $A` VYJtt#  
fX+O[j  
0^ibNiSP  
public void setSSiteURL(String value) '\GbmD^F  
{ v}x&?fU `  
sSiteURL = value; G9 :l'\  
} Z)\@i=m  
K@#L)VT!  
d/Q%IeEL.  
public String getSFilePath() )ANmIwmC#  
{ [9 RR8  
return sFilePath; EZj9wd"u  
} N?>vd*  
`@ FYkH  
jSAjcLR  
public void setSFilePath(String value) 0L KRN|@  
{ s0_nLbWwO  
sFilePath = value; aA TA9V  
} 9E tz[`|  
e]tDy0@  
h@h!,;  
public String getSFileName() `p7=t)5k  
{ V!dtF,tH  
return sFileName; 5D l/aHb  
} CA#,THty  
u4_9)P`]0  
W T}H>T  
public void setSFileName(String value) H4JTGt1"  
{ l (%1jC8  
sFileName = value; (M ~e?s  
} ,1##p77.  
N"1B/u  
M xG W(p  
public int getNSplitter() #u + v_  
{ _,d~}_$`i  
return nSplitter; @fV9 S"TcM  
} 69 o 7EA  
.}`Ix'.  
lA-h`rl /  
public void setNSplitter(int nCount) xjUtl  
{ N&V`K0FU  
nSplitter = nCount; g>9kXP+  
} d'I"jZ  
} w'3iY,_ufC  
-Vhw^T1iV  
&=k,?TJO>  
/* =kqt   
**Utility.java :Lug7bUVD  
*/  JSg$wi8  
package NetFox; Y)a^(!<H<  
evJ.<{M  
8h4'(yGQQW  
public class Utility { Yir [!{  
 0{ [,E.  
C{b gkzr  
public Utility() BV+ Bk+  
{ S/I/-Bp~  
(2 a`XwR  
.-X8J t  
} .y,0[i V N  
~| 6[j<ziL  
//线程睡眠 K}U-w:{  
public static void sleep(int nSecond) WSY}d Vr  
{ Zoc0!84<z  
try{ EUgs6[w 4  
Thread.sleep(nSecond); zZC9\V}R  
} V,?yPi$#E  
catch(Exception e) .K<Q&  
{ ED& `_h7?  
e.printStackTrace (); / Qk4  
} kn"(A .R  
} mo#04;VF  
gOOPe5+ J  
//日志 Vl!6W@g  
public static void log(String sMsg) (NnH:J`  
{ t>B;w14  
System.err.println(sMsg); <kd1Nrr!p  
} SG4%}wn%  
BIWWMg  
[\b 0Lem  
public static void log(int sMsg) 8&Y^""#e)  
{ M+9gL3W  
System.err.println(sMsg); #`X?=/q  
} )Iq<+IJ  
} :Qf '2.h)  
f.`*Qg L  
78%~N`x7  
/* <nK?LcP  
**TestMethod.java mcX/GO}  
*/ 9lDhIqx0~  
package NetFox; J{&H+rd  
r_;N t  
=6|&Jt  
public class TestMethod { A7hVHxNJ-  
g!z&~Z:  
1q1jZqno  
public TestMethod() klR|6u]%  
{ ///xx/weblogic60b2_win.exe fLm*1S|%\  
try{ |WdPE@P  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3J438M.ka  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yD6[\'%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); gy9U2Wgf|  
fileFetch.start(); _1L![-ac  
} }:*]aL<7_  
catch(Exception e){e.printStackTrace ();} x*&|0n.D  
#3 pb(fbw  
B|AV$N*  
} RT J3qhY  
fCobzDy  
eS mLf*\G  
public static void main(String[] args)  fGw9!  
{ R= o2K  
new TestMethod(); 1"M]3Kl  
} %(G* ,  
} v(D;PS3r 7  
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