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http断点续传简单实现(java)

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/* #u<Qc T@  
**SiteFileFetch.java #F*|@  
*/ JuRoeq.  
package NetFox; 'Pz%c}hJ  
import java.io.*; ]AP1+ &9fN  
import java.net.*; GnV0~?  
<?jd NM  
93-Y(Xx)bY  
public class SiteFileFetch extends Thread { ~m%[d. }e  
>&L|oq7$  
Vla,avON  
SiteInfoBean siteInfoBean = null; //文件信息Bean IS C.~q2  
long[] nStartPos; //开始位置 B.<SC  
long[] nEndPos; //结束位置 a(Y'C`x  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *2X6;~  
long nFileLength; //文件长度 ~/:vr  
boolean bFirst = true; //是否第一次取文件 h@)U,&  
boolean bStop = false; //停止标志 KuNLu31%  
File tmpFile; //文件下载的临时信息 WSThhI  
DataOutputStream output; //输出到文件的输出流 +,Dc0VC?  
G#iQX`  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) q:{#kv8  
public SiteFileFetch(SiteInfoBean bean) throws IOException )!y>2$20 r  
{ 2FcL-?  
siteInfoBean = bean; 4Nm>5*]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >hKsj{=R7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^Fk;t  
if(tmpFile.exists ()) Q&m85'r5X  
{ fV:15!S[  
bFirst = false; c? ::l+  
read_nPos(); 77e*9/6@  
} ^df wWP  
else Z['.RF'`  
{ J )1   
nStartPos = new long[bean.getNSplitter()]; dzcF1 5H1  
nEndPos = new long[bean.getNSplitter()]; ;!yK~OBxt  
} CjdM*#9lW  
?z ,!iK`  
*[MWvs:,  
rK~-Wzwu  
} *0WVrM06?  
{f*Y}/@  
\BOoY#!a  
public void run() ,|%KlHo^  
{ 3CUQQ_  
//获得文件长度 I-v} DuM  
//分割文件 #ydold{F  
//实例FileSplitterFetch 9O[IR)O~  
//启动FileSplitterFetch线程 Ht`fC|E  
//等待子线程返回 /iW+<@Mas  
try{ ]kh]l8t^  
if(bFirst) Rq4; {a/j  
{ >Wg= Tuef  
nFileLength = getFileSize(); rOIb9:  
if(nFileLength == -1) i4C{3J^  
{ ?2<QoS  
System.err.println("File Length is not known!"); ",r v%i2 f  
} G  hM  
else if(nFileLength == -2) #h!+b  
{ c '|*{%<e2  
System.err.println("File is not access!"); |jsI-?%8J  
} ktu?-?#0,  
else RK# 6JfC3X  
{ !E70e$Th  
for(int i=0;i<nStartPos.length;i++) B`pBIUu  
{ cJKnB!iL5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); UhB +c  
} ?7\V)$00(&  
for(int i=0;i<nEndPos.length-1;i++) UG1<Xfu|  
{ ,f03TBD}  
nEndPos = nStartPos[i+1]; l;F"m+B!$  
} 3 ML][|TR  
nEndPos[nEndPos.length-1] = nFileLength; fif;n[<  
}  ^`H'LD  
} /4{WT?j  
^Z (cV g  
s5,@=(,  
//启动子线程 F`}'^>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; " <bjS  
for(int i=0;i<nStartPos.length;i++) 'CBwE&AL  
{ X[z;P!U  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ODJ"3 J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !G%!zNA S  
nStartPos,nEndPos,i); tpI/I bq  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m:_#kfC&K"  
fileSplitterFetch.start(); "|\hTRQ  
} V[ UOlJ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g4W$MI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :?f<tNU$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Aez2n(yac  
nEndPos = " + nFileLength); 4S(G366  
// fileSplitterFetch[nPos.length-1].start(); lp*5;Ls'q  
/Pjd"  
H UJqB0D ?  
//等待子线程结束 mQj#\<*  
//int count = 0; eI-fH  
//是否结束while循环 6Ga'_P:  
boolean breakWhile = false; >iyNZ]."\  
r$<!?Z  
l,n_G/\  
while(!bStop) 4DIU7#GG  
{ k_g@4x1y*  
write_nPos(); b~;:[ #  
Utility.sleep(500); Y58H.P  
breakWhile = true; '[ c-$X2Ak  
-=-^rQx9  
5N9Cd[4  
for(int i=0;i<nStartPos.length;i++) s:<y\1Ay  
{ e`Yj}i*bx]  
if(!fileSplitterFetch.bDownOver) %+r(*Q+0$f  
{ |\bNFnn(  
breakWhile = false;  hyxv+m[  
break; Zl_sbIY  
} HSud$(w  
} e"@r[pq-{u  
if(breakWhile) g.\b@0Uy'  
break; E2Sj IR}  
CfOyHhhKX  
/}u:N:HA%  
//count++; u`EK^\R  
//if(count>4) J5b3r1~D"[  
// siteStop(); ErN[maix#  
} #h.N#{9  
t{,$?}  
>MJ %6A>  
System.err.println("文件下载结束!"); 3 EAr=E]  
} *b;)7lj0h  
catch(Exception e){e.printStackTrace ();} /5%'q~  
} yXkQ ,y  
}[%F  
!,- 'wT<v  
//获得文件长度 9f['TG,"  
public long getFileSize() 6l|L/Z_6  
{ l[ko)%7V  
int nFileLength = -1; M"mvPr9  
try{ "eoPG#]&  
URL url = new URL(siteInfoBean.getSSiteURL()); "P.sK huo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 02 FLe*zQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); (9bU\4F\  
U>Is mF>m  
*3^7'^j<  
int responseCode=httpConnection.getResponseCode(); |yNyk7~  
if(responseCode>=400) '>OEQU5-  
{ ;E}&{w/My  
processErrorCode(responseCode); 7|Vpk&.>  
return -2; //-2 represent access is error ]Y & 2&  
} ,>g( %3C  
'bv(T2d~~  
&WCVdZK:  
String sHeader; 7d{xXJ-  
q.:a4w J  
6o#J  
for(int i=1;;i++) 9U9ghWH8  
{ ^=I[uX-3ue  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); tIA)LF  
//Utility.log(in.readLine()); vr>J$(F  
sHeader=httpConnection.getHeaderFieldKey(i); *~`oA~-Q  
if(sHeader!=null) Z(E .F,k  
{ u`L*  
if(sHeader.equals("Content-Length")) 11$v~<M  
{ O[ans_8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4pDZ +}p  
break; U:/_T>f%  
} v@X[0J_8  
} Mc  
else JjAO9j%  
break; kSJ:4!lFU  
} Cn9MboXX  
} 8BIPEY -I?  
catch(IOException e){e.printStackTrace ();} c1]\.s  
catch(Exception e){e.printStackTrace ();} ?s0")R&  
jaTCRn3|<  
*!EHs04  
Utility.log(nFileLength); UR`pZ.U?  
QD[l 6  
|?fc]dl1]  
return nFileLength; m<9W#  
} WtSlD9 h  
=2wy;@f  
ku5g`ho  
//保存下载信息(文件指针位置) el0W0T  
private void write_nPos() a'@?c_y;$  
{ K)oN^  
try{ 1n ZE9;o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); LD5E  
output.writeInt(nStartPos.length); xeHqC9Ou  
for(int i=0;i<nStartPos.length;i++) -E!V;Tgc%U  
{ #`Et{6W S  
// output.writeLong(nPos); > cJX'U9  
output.writeLong(fileSplitterFetch.nStartPos); -aMwC5iR@  
output.writeLong(fileSplitterFetch.nEndPos); !FnH;  
} 2TC7${^9}J  
output.close(); =HvLuVc  
} F9SIC7}uH  
catch(IOException e){e.printStackTrace ();} j#XU\G  
catch(Exception e){e.printStackTrace ();} (aH_K07  
} 7<ES&ls_  
q} R"  
vCNYqa)m:  
//读取保存的下载信息(文件指针位置) jZY9Lx8o  
private void read_nPos() ;c>Rjg&[  
{ 'uOp?g'7  
try{ Ie;}k;?-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); seH#v  
int nCount = input.readInt(); :!EOg4%i  
nStartPos = new long[nCount]; WxLILh  
nEndPos = new long[nCount]; ]+S.#x`#  
for(int i=0;i<nStartPos.length;i++) pRdO4?l  
{ &"svt2  
nStartPos = input.readLong(); h:+>=~\  
nEndPos = input.readLong(); ZjJEjw  
} T+/Gz'  
input.close(); 2\!.w^7'^T  
} xH8nn3U  
catch(IOException e){e.printStackTrace ();} :U;ZBs3  
catch(Exception e){e.printStackTrace ();} 86@@j*c(@k  
} )Nq$~aAm  
yyHr. C  
t UW'E  
private void processErrorCode(int nErrorCode) Zt[1RMO  
{ 4d3PF`,H`  
System.err.println("Error Code : " + nErrorCode); yz2NB?)  
} N|1k6g=0  
m[u 6<C  
Hw/1~O$T  
//停止文件下载 Z)(C7,Xu  
public void siteStop() C`x>)wm:  
{ 'u.`!w '|L  
bStop = true; an<tupi[E  
for(int i=0;i<nStartPos.length;i++) L+QEFQ:r5  
fileSplitterFetch.splitterStop(); @*l}2W  
M|`%4vk>  
4 ITSDx  
} *-Y|qS%  
} 0:nQGX!N  
//负责部分文件的抓取 (85F1"Jp  
**FileSplitterFetch.java ?P`]^#  
*/ U]ouBG8/  
package NetFox; Hj;j\R >2  
+3t(kQ  
$X-,6*  
import java.io.*; `pN]Ykt  
import java.net.*; qx53,^2  
\"PlM!0du  
mrd(\&EhA  
public class FileSplitterFetch extends Thread { Ef$xum{  
-D.6@@%Kc}  
c#`Z[  
String sURL; //File URL K=Fcy#, f  
long nStartPos; //File Snippet Start Position E<&VK*{zcO  
long nEndPos; //File Snippet End Position 6576RT  
int nThreadID; //Thread's ID ~&4,w9b)j  
boolean bDownOver = false; //Downing is over 0/(YH  
boolean bStop = false; //Stop identical [?Aq#av  
FileAccessI fileAccessI = null; //File Access interface 1/w['d4l!  
NRq jn; ,+  
UmQ 9_H7  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException iQin|$F_O  
{ yNY1g?E  
this.sURL = sURL; rMf& HX  
this.nStartPos = nStart; D@d/O  
this.nEndPos = nEnd; +69sG9BA  
nThreadID = id; 6eK18*j%H  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 D 7H$!(F>  
} |'=R`@w~0  
d%4!d_I<  
j t-ayLq  
public void run() KH2a 2  
{ +l&ZN\@0X  
while(nStartPos < nEndPos && !bStop) yZA }WTGe  
{ HK5\i@G+<  
YJXh|@LT  
pt|u?T_+  
try{ \nPa>2r  
URL url = new URL(sURL); Scs \nF2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,p>=WX  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^^)D!I"cA,  
String sProperty = "bytes="+nStartPos+"-"; =Q Otag1;  
httpConnection.setRequestProperty("RANGE",sProperty); @y)-!MHN(8  
Utility.log(sProperty); RNp3lXf O  
xC!,v 0&  
qeSxE`E"  
InputStream input = httpConnection.getInputStream(); x@Z?DS$)  
//logResponseHead(httpConnection); #ra:^9;Es:  
4 K{4=uU  
&d9tR\}  
byte[] b = new byte[1024]; z)yxz:E  
int nRead; S#_i<u$$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) JTQ$p*2]  
{ KDwjck"5;  
nStartPos += fileAccessI.write(b,0,nRead); 8GV$L~i  
//if(nThreadID == 1)  [L] ca*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qnv9?Xh  
} C-m OtI  
6#KRI%adw`  
2\lUaC#E  
Utility.log("Thread " + nThreadID + " is over!"); RBJgQ<j8  
bDownOver = true; '1|r+(q|2  
//nPos = fileAccessI.write (b,0,nRead); 4U~[ 8U}g  
} 4=>/x90y  
catch(Exception e){e.printStackTrace ();} j!qO[CJJ  
} ^'*9,.ltd  
} 70mQ{YNN  
B@=+Fg DD  
VLA9&.*@  
//打印回应的头信息 *pyi;  
public void logResponseHead(HttpURLConnection con) b;Pqq@P|g  
{ H)G ^ Y1  
for(int i=1;;i++) ,c YU  
{ uRh`qnL  
String header=con.getHeaderFieldKey(i); h$G&4_O  
if(header!=null) yx4B!U  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); j{0_K +B  
Utility.log(header+" : "+con.getHeaderField(header)); TfDx> F$  
else qeb:n$  
break; |/Am\tk#13  
} 0:@:cz=#*  
} x0?8AG%  
88$G14aXEk  
's8NO Xlj  
public void splitterStop() SVpvx`&kT  
{ L8Z[Ly+_  
bStop = true; /KO!s,Nk  
} WhMr'l/e  
'{@hBB+ D  
@c,}\"(  
} 5^t68 WOl  
]m{;yOQdsC  
KIps {_J[<  
/* -P]J:7*0?\  
**FileAccess.java VTa?y  
*//文件访问(定位,写) KN'l/9.  
package NetFox; |qE"60&"}  
import java.io.*; ) **k3u t4  
JR<#el  
3/H^YM @  
public class FileAccessI implements Serializable{ c BQ|m A  
{:$0j|zL1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 WIb\+!  
RandomAccessFile oSavedFile; +*WE<4"!6  
long nPos; kzZtKN9Az  
`zAV#   
y@ J\h8_  
public FileAccessI() throws IOException D9B?9Qt2[  
{ :c"J$wT/  
this("",0); I1=YSi;A  
} hun L V8z  
B08q/ qi  
f&bY=$iff  
public FileAccessI(String sName,long nPos) throws IOException [Qa0uM#SU  
{ s[)2z3  
oSavedFile = new RandomAccessFile(sName,"rw"); 8XD9fB^  
this.nPos = nPos; Z'6 o$Xv  
oSavedFile.seek(nPos); >|KfO>  
} JAj<*TB.%  
[ -bL>8  
W1$B6+}Z0V  
public synchronized int write(byte[] b,int nStart,int nLen) j_-$xz5-  
{ - o$S=  
int n = -1; 0I* ^VGZ  
try{ _|D8~\y  
oSavedFile.write(b,nStart,nLen); u`$,S& Er  
n = nLen; %?J\P@  
} 2/RK pl &  
catch(IOException e) e<dFvMO  
{ G'q7@d {'  
e.printStackTrace (); d}3<nz,  
} I&3L1rl3{*  
F IDNhu  
l]Jk  }.  
return n; m1a0uEA G  
} >Y?B(I2e  
R!lNm,i  
aD8cqVhM3&  
} |jJC~/WR  
)I9AF,K  
Y=sRVypJ  
/* Mii-Q`.:  
**SiteInfoBean.java Na=9 ju  
*/ VG*BAFs  
package NetFox; I >k3X~cG  
8s-RNA>7^  
u{"o*udU  
public class SiteInfoBean { EC&t+"=R  
{cnya*  
38b%km#  
private String sSiteURL; //Site's URL 2/sD#vC  
private String sFilePath; //Saved File's Path w&f8AY)#]4  
private String sFileName; //Saved File's Name *E+2E^B  
private int nSplitter; //Count of Splited Downloading File }OJ*o  
`sQ\j Nu  
@4^5C-  
public SiteInfoBean() L^yQb4$&M  
{//nSplitter的缺省值为5 E D*=8 s2  
//default value of nSplitter is 5 .21%~"dxJ  
this("","","",5); >Bq;Z}EV  
} 6_=qpP-?  
JQYIvo1,Q  
iaQ[}'6!$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :k6|-A2  
{ k:4 Z c3  
sSiteURL= sURL; 8jd<|nYnfc  
sFilePath = sPath; 6%H8Q v  
sFileName = sName; vC E$)z'"  
this.nSplitter = nSpiltter; +"Ih'bb`j  
v Q[{<|K  
iC?s`c0B  
} sqi~j(&\1  
wXPNfV<(2  
bM;yXgorU  
public String getSSiteURL() >"jV8%!sM  
{ ,pa,:k?  
return sSiteURL; /%po@Pm#I  
} Dx$74~2e  
Ev0GAc1  
Iwi>yx8  
public void setSSiteURL(String value) .{k(4_Q?I  
{ I+D`\OSL  
sSiteURL = value; leiED'  
} |xZDc6HDW  
r(yJE1Wz  
x5v^@_: jr  
public String getSFilePath() 0(|R N V_  
{ GC66n1- X  
return sFilePath; _DMj )enH"  
} B, xrZs  
<Xm5re.  
vY *p][$  
public void setSFilePath(String value) }U7>_b2  
{ 2n?\tOm(V  
sFilePath = value; [P OcO  
} cx|[P6d  
($E(^p% O  
|(}uagfrd  
public String getSFileName() Vm'ReH  
{ >ly= O  
return sFileName; w!:u|  
} (sS[F-2R7  
reM%GU  
+6*oO|   
public void setSFileName(String value) t"2WJ-1k}  
{ <3P?rcd,5K  
sFileName = value; &|%z!x6f  
} I m_yY  
c1wgb8  
dS0G+3J&+E  
public int getNSplitter() \>cZ=  
{ 9XT6Gf56  
return nSplitter; Mki(,Y|1~  
} cy)L%`(7  
sa#=#0yg  
$MKx\qx}  
public void setNSplitter(int nCount) 1(w0* `  
{ ]WN{8   
nSplitter = nCount; (loUO;S=  
} fL83:<RK  
} o1MbHBb  
#Q 2$v;  
o|]xj'  
/* $msT,$NJ  
**Utility.java b$PNZC8f  
*/ ?-#w [J'6  
package NetFox; ~W5 fJd0  
> m}.}g8  
GJ%It .  
public class Utility { @ )<uQ S  
z9h`sY~  
xw%?R=&L  
public Utility() eX?o 4>  
{ \5s!lv*&  
-jC. dz  
SnQ$  
} jt3s;U*  
cB.v&BSW  
//线程睡眠 ed{z^!w4  
public static void sleep(int nSecond) Mk@_uPm  
{ zG [-n.  
try{ &JfyXM[]  
Thread.sleep(nSecond); k B2+ Tr  
} T%P 0M*  
catch(Exception e) rxP^L(q0*  
{ VrF]X#\)  
e.printStackTrace (); r2""p  
} E'MMhl o  
} gl]{mUZz}  
~JC``&6E=}  
//日志 {zVJlJKxs  
public static void log(String sMsg) sB7DF<91  
{ ]NTHit^EX  
System.err.println(sMsg); R#1m_6I  
} Fi7pq2  
JG/sKOlA  
ReSP)%oW  
public static void log(int sMsg) HkEp}R  
{ c%xxsq2n  
System.err.println(sMsg); :+E>Uz T  
} AqN(htGvx  
} v`wPdb  
SvI  
5n(p 1OM2q  
/* v+Mt/8  
**TestMethod.java 2a? d:21 B  
*/ rTmcP23]  
package NetFox; WU=Os8gR  
!*CL>}-,  
DCw ldkdJN  
public class TestMethod { X^aujK^@  
i g?]kZ  
.' X$SF`  
public TestMethod() P_b00",S  
{ ///xx/weblogic60b2_win.exe !_x-aro3<  
try{ P6IhpB59  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pdtK3Pf  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N18Zsdrp  
SiteFileFetch fileFetch = new SiteFileFetch(bean); A`OU} 'v?L  
fileFetch.start(); V]vk9M2q[l  
} ;| \Ojuf  
catch(Exception e){e.printStackTrace ();} N k^#Sa?  
:j9;P7&"?  
JY>]u*=  
} [8)Zhw$  
M%$zor  
66z1_ lA  
public static void main(String[] args) lHP[WO  
{ j\Q_NevV  
new TestMethod(); nnr(\r~  
} y YF80mnJz  
} bLf }U9  
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