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http断点续传简单实现(java)

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/* N;HG@B!m  
**SiteFileFetch.java *`_ 2uBz  
*/ BM o2t'L  
package NetFox; :anR/  
import java.io.*; $qR<_6j  
import java.net.*; k|^YYi= xF  
KY%LqcC  
h:AB`E1  
public class SiteFileFetch extends Thread { (Fj"<  
~c=F$M^"c  
#Q1 |]  
SiteInfoBean siteInfoBean = null; //文件信息Bean dC/@OV)0#  
long[] nStartPos; //开始位置 V}MRdt7  
long[] nEndPos; //结束位置 Qp;FVUw9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;04< 9i  
long nFileLength; //文件长度 arc{:u.K  
boolean bFirst = true; //是否第一次取文件 w.(?O;  
boolean bStop = false; //停止标志 U+Vb#U7;  
File tmpFile; //文件下载的临时信息 >|pN4FS  
DataOutputStream output; //输出到文件的输出流 a0jzt!ci  
ydTd.`  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Gn%"B6  
public SiteFileFetch(SiteInfoBean bean) throws IOException (]nX:t  
{ Hva/C{Y  
siteInfoBean = bean; z?Cez*.h>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;LC?3.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (@Kc(>(: Y  
if(tmpFile.exists ()) )&$mFwf  
{ aM4-quaG]  
bFirst = false; 4 'DEdx,&f  
read_nPos(); z?t75#u9.  
} %l3f .  
else #l 6QE=:  
{ S "/-)_{  
nStartPos = new long[bean.getNSplitter()]; 'A,)PZL9i  
nEndPos = new long[bean.getNSplitter()]; R:`)*=rL%  
} i~LY  
$=5kn>[_Z%  
e0M'\'J  
`|<? sjY  
} d5"rCd[  
MJA;P7g  
XE8%t=V!c$  
public void run() 2Z-QVwa*U  
{ 3*E] :l_  
//获得文件长度 &W}6Xg(  
//分割文件 cEIs9;  
//实例FileSplitterFetch c5Hyja=  
//启动FileSplitterFetch线程 TSH'OW !b  
//等待子线程返回 X.V4YmZ- ;  
try{ #fDM{f0]R  
if(bFirst) B%WkM\\!^  
{ lf\^!E:  
nFileLength = getFileSize(); G8.nKoHv7x  
if(nFileLength == -1) G0he'BR  
{ ^vJy<  
System.err.println("File Length is not known!"); A: O"N  
}  L+CPT  
else if(nFileLength == -2) oS~;>]W  
{ +OZ\rs  
System.err.println("File is not access!"); Ek60[a  
} q<K/q"0-l  
else NFPWh3),f  
{ lMgPwvs'  
for(int i=0;i<nStartPos.length;i++) v\+`n^=  
{ 3pe1"maP  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); p/HGI)'  
} 3U'l'H,  
for(int i=0;i<nEndPos.length-1;i++) A@eR~Kp ^  
{ 30O7u3Zrb  
nEndPos = nStartPos[i+1]; *6G@8TIh  
} "|BSGV!8  
nEndPos[nEndPos.length-1] = nFileLength; "-Pz2QJY  
} iZ4"@G:,  
} Fw8b^ew  
;u=%Vn"2a  
qYQ vjp  
//启动子线程 @SI,V8i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; pwRCfR)"X  
for(int i=0;i<nStartPos.length;i++)  7gx?LI_e  
{ o?^Rw*u0/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ByacSN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0]zMb^wo  
nStartPos,nEndPos,i); +p$lVnAt  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  F##xVmR~  
fileSplitterFetch.start(); 03.\!rZZ  
} e@1A_q@.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aMGyV"6(-6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !;K zR&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", viJP6fh  
nEndPos = " + nFileLength); i.^:xZ  
// fileSplitterFetch[nPos.length-1].start(); &UNQ4-s  
EMDYeXpV  
?Iu=os>*  
//等待子线程结束 ff]fN:}V  
//int count = 0; r[wjE`Z/T  
//是否结束while循环 PsZ>L  
boolean breakWhile = false; g@.e%  
99"8d^{z  
GE? \Vm  
while(!bStop) `lrNH]B  
{ r]U8WM3r  
write_nPos(); w&e3#p  
Utility.sleep(500); wB:<ICm  
breakWhile = true; nX\mCO4T  
l&5Tft  
IG:2<G  
for(int i=0;i<nStartPos.length;i++) 13 %: 3W(  
{ !L<z(dV|(  
if(!fileSplitterFetch.bDownOver) Xpt9$=d  
{ Xc4zUEO9  
breakWhile = false; <+<Nsza  
break; /(?s\}O  
} clk]JA (  
}  n}- _fx  
if(breakWhile) 8c>xgFWp9  
break; C;%dZ  
S~R[*Gk_uT  
;%k C?Vzi  
//count++; z`p9vlS[  
//if(count>4) ~z,qr09  
// siteStop(); <AK9HPxP  
} .Hk.'>YR  
R7KV @n  
$<"I*l@  
System.err.println("文件下载结束!");  y(#6nG@S  
} o' v!83$L  
catch(Exception e){e.printStackTrace ();} yivWT;`  
} ~SmFDg$/m  
IfT: 9 &  
/x4L,UJ= P  
//获得文件长度 p 16+(m  
public long getFileSize() +DO<M1uE  
{ LXZI|K[}k  
int nFileLength = -1; 3`)ej`  
try{ G&t|aY-   
URL url = new URL(siteInfoBean.getSSiteURL()); 7#SfuZ0@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8n:N#4Dh^  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0JKTwLhC  
i52JY&N  
jfVw{\l  
int responseCode=httpConnection.getResponseCode(); sk*vmxClY  
if(responseCode>=400) i|xz  
{ .&`apQD}  
processErrorCode(responseCode); QjD=JC+  
return -2; //-2 represent access is error 1f'msy/  
} 6!N2B[9  
A8o)^T(vJ  
i g .  
String sHeader; P s<k2  
5X9Lh_p  
 Pa?{}A  
for(int i=1;;i++) fsWIz1K  
{ nrX+  '  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); i r'C(zD=  
//Utility.log(in.readLine()); \(&&ed:  
sHeader=httpConnection.getHeaderFieldKey(i); cmAdQ)(Kzd  
if(sHeader!=null) <_]W1V:0  
{ '=eVem=  
if(sHeader.equals("Content-Length")) fJ6Q:7  
{ $*LBZcL  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sZ7~AJ  
break; j)#yyK{k2s  
} 7j29wvSp5  
} @1' Y/dCyD  
else EWY'E;0@5  
break; ZE= Yn~XM  
} *xITMi  
} Xbrc_ V\_  
catch(IOException e){e.printStackTrace ();} WJ LqH<  
catch(Exception e){e.printStackTrace ();} }%<_>b\  
9XhH*tBn7(  
?YUL~P  
Utility.log(nFileLength); V DZOJM)(  
]EUQMyR  
Z[B:6\oQ  
return nFileLength; E|jU8qz>P  
} l2YA/9.  
g_A#WQyh\'  
7%[ YX  
//保存下载信息(文件指针位置) |.$7.8g  
private void write_nPos() MOay^{u  
{ NFC/4  
try{ C\vOxBAB  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,yvS c  
output.writeInt(nStartPos.length); t OxH9  
for(int i=0;i<nStartPos.length;i++) d0&  
{ mahNQ5W*)  
// output.writeLong(nPos); =+I-9=  
output.writeLong(fileSplitterFetch.nStartPos); <M}O&?N 8x  
output.writeLong(fileSplitterFetch.nEndPos); #{^qBP[  
} g#Ta03\  
output.close(); y y[Y=  
} YU!s;h  
catch(IOException e){e.printStackTrace ();} cSNeWJKA6  
catch(Exception e){e.printStackTrace ();} 4i5b.b U$  
} |sl^4'Ghc  
3+vVdvu%  
 rvK%m_r  
//读取保存的下载信息(文件指针位置) 8j :=D!S  
private void read_nPos()  K V  
{ v(=0hY9 O  
try{ g!o2vTt5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,V^$Meh  
int nCount = input.readInt(); *OIBMx#qxn  
nStartPos = new long[nCount]; I_kA!^  
nEndPos = new long[nCount]; n3qRt  
for(int i=0;i<nStartPos.length;i++) )C mHC3  
{ ]0MuXiR  
nStartPos = input.readLong(); p=zTY7L  
nEndPos = input.readLong(); y~\uS  
} F%af05L[  
input.close(); rkR~%U6V  
} 5tzO=gO[  
catch(IOException e){e.printStackTrace ();} <`NsX 6t  
catch(Exception e){e.printStackTrace ();} 5h Dy62PRr  
} [N}QCy  
<"xqt7f  
GCX?W`  
private void processErrorCode(int nErrorCode) JNJ6HyCU  
{ 9sd}Z,l  
System.err.println("Error Code : " + nErrorCode); l4(FM}0X5}  
} &-X51O C  
8V9OMOt!  
=dQ/^C_hj  
//停止文件下载 4\g[&  
public void siteStop() ;DVg[#  
{ :^xNHMp!  
bStop = true; *[BtW5 6-  
for(int i=0;i<nStartPos.length;i++) P=\Hi.]%  
fileSplitterFetch.splitterStop(); gW9`k,U  
R,=8)OI2  
q">}3`k  
} zjSl;ru  
} 7zJ2n/`m*  
//负责部分文件的抓取 IN;9p w  
**FileSplitterFetch.java `&xdSH  
*/ [TFp2B~)#  
package NetFox; 8lS RK%  
wzJdS}Yy!y  
n2Mpo\2  
import java.io.*; pG"h ZB3)  
import java.net.*; AZA5>Y  
@$ lX%p>  
g jzWW0C  
public class FileSplitterFetch extends Thread { Dhfor+Epy  
 6pfkv2.}  
&GvSgdttv  
String sURL; //File URL ~l{Qz0&  
long nStartPos; //File Snippet Start Position W}}ZP];  
long nEndPos; //File Snippet End Position {fX~%%c"  
int nThreadID; //Thread's ID JG1q5j##]b  
boolean bDownOver = false; //Downing is over s0/m qZ]s  
boolean bStop = false; //Stop identical 2tCw{Om*  
FileAccessI fileAccessI = null; //File Access interface VB T 66kV  
W tHJG5  
q5@Nd3~h  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 51H6 W/$  
{ |W@Ko%om  
this.sURL = sURL; {?EmO+![}  
this.nStartPos = nStart; |$ZS26aYw}  
this.nEndPos = nEnd; ZM <UiN  
nThreadID = id; 81(\8#./  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 sG[qlzR=8  
} J$s p6 g>K  
'zT7$ .L  
a|#pl!  
public void run() 1 XJZuv,T:  
{ [7[Qw]J  
while(nStartPos < nEndPos && !bStop) pF8:?p['z  
{ * LWihal  
p>:.js5.a  
(n jTS+?  
try{ 4;gw&sFF  
URL url = new URL(sURL); ggYi7Wzsd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F M YcZ+4  
httpConnection.setRequestProperty("User-Agent","NetFox"); jVN=_Y}\  
String sProperty = "bytes="+nStartPos+"-"; d(R8^v/L  
httpConnection.setRequestProperty("RANGE",sProperty); -vk/z+-^!  
Utility.log(sProperty); ,# .12Q!  
JP {`^c  
jUR* |  
InputStream input = httpConnection.getInputStream(); $ndBT+ i  
//logResponseHead(httpConnection); ]Y76~!N  
LTH, a?lD  
X*d!A >s  
byte[] b = new byte[1024]; dn Xu(e%  
int nRead; ,!g/1m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9f5~hBlo  
{ LmJ _$?o  
nStartPos += fileAccessI.write(b,0,nRead); #UI`+2w  
//if(nThreadID == 1) Yl$ @/xAa  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l[m*csDk"  
} H1KXAy`&  
M(C}2.20  
)`\Q/TMl5  
Utility.log("Thread " + nThreadID + " is over!"); ^T1caVb|>  
bDownOver = true; Us2> 5 :\  
//nPos = fileAccessI.write (b,0,nRead); ,1JQjsR   
} hb/Z{T'   
catch(Exception e){e.printStackTrace ();} XpK  Y#  
} es.Y  
} >TawJ"q-6R  
Nlwt}7  
Z("N *`VP;  
//打印回应的头信息 \_(0V"  
public void logResponseHead(HttpURLConnection con) qNrLM!Rj  
{ eoQt87VCU  
for(int i=1;;i++) ^nOh 8L;  
{ H_Sv,lwz;c  
String header=con.getHeaderFieldKey(i); P *PJ  
if(header!=null) CL-?Mi=Uc  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); g/P1lQ)  
Utility.log(header+" : "+con.getHeaderField(header)); *`/4KMrq  
else w T_l>u  
break; <@+L^Ps~z  
} NE) w$>0M  
} M\7F1\ X  
48G^$T{  
BC1smSlJ  
public void splitterStop() ;4/ n~  
{ Jcs /i  
bStop = true; vQnhb %  
} E piF$n  
'xa EG,P  
YZnFU( j  
} -y?ve od#  
*H=h7ESq  
T%Zfo7  
/* 6Rq +=X  
**FileAccess.java e},:QL0X  
*//文件访问(定位,写) xt`a":lru  
package NetFox; HL>l.IG?  
import java.io.*; wq1s#ag<  
`w@z Fc!"  
rd[mC[ r  
public class FileAccessI implements Serializable{ T<y fpUzX  
~G6xk/+n-m  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7X> @r"9<  
RandomAccessFile oSavedFile; X`eX+9  
long nPos;  dBN:  
{`J!DFfur  
(r}StR+  
public FileAccessI() throws IOException oq1wU@n  
{ l-h[I>TW  
this("",0); ^U,C])n  
} a_b+RMy  
By}ZHK94I  
,,#6SR(n  
public FileAccessI(String sName,long nPos) throws IOException 78?{;iNv  
{ WUQa2$.  
oSavedFile = new RandomAccessFile(sName,"rw"); \X]I: 0^j  
this.nPos = nPos; p#r qe<Ua  
oSavedFile.seek(nPos); 16.?4 5  
} >Apa^Bp  
dI=&gz  
&fkH\o7)  
public synchronized int write(byte[] b,int nStart,int nLen) B/3xV:Gy  
{ 19oyoi"  
int n = -1; d+ $:u  
try{ 3(.Y>er%U  
oSavedFile.write(b,nStart,nLen); k{ZQM  
n = nLen; ?A*<Z%}1?  
} A4;~+L:M  
catch(IOException e) )2Y]A^Y   
{ jC?l :m?  
e.printStackTrace (); b0se-#+  
} 3k8. 5W  
%6M%PR~u  
!Ow M-t  
return n; X;vU z  
} 8hyX He  
#X'su`+  
3qV\XC+  
} Z*NTF:6c  
9 uX 15a  
]Al)>  
/* RcO.1@2  
**SiteInfoBean.java [?2?7>D8  
*/ u'Hh||La"  
package NetFox; X~\O]  
n4H'FZ  
9]/:B8k  
public class SiteInfoBean { s,Fts3+  
-h8Z@r~a/  
6D{70onY+  
private String sSiteURL; //Site's URL * $1F|G  
private String sFilePath; //Saved File's Path X>]<rEh  
private String sFileName; //Saved File's Name lx?v .:zl\  
private int nSplitter; //Count of Splited Downloading File c+whpQ=01  
wp:Zur5Y  
65mfq&"P ?  
public SiteInfoBean() ,k9.1kjO*)  
{//nSplitter的缺省值为5 1$m{)Io2(  
//default value of nSplitter is 5 2) 2:KX  
this("","","",5); c <Q*g  
} }ZiJHj'<  
eV;nTj  
Q yQ[H  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \y7Gi}nI  
{ C}9|e?R[Rz  
sSiteURL= sURL; {q;_Dd  
sFilePath = sPath; .I^Y[_.G  
sFileName = sName; -Wre4 ^,v  
this.nSplitter = nSpiltter; 7.kH="@  
'CG% PjCO  
t [G7&ovj  
} 9p4SxMMO  
:)+)L@By  
M}=fdH  
public String getSSiteURL() uY3#,  
{ Uqly|FS &n  
return sSiteURL; Ms+SJ5Lg  
} !rG-[7K  
6eNBldP!  
bp}]'NA  
public void setSSiteURL(String value) Ngm/5Lc  
{ 8'v:26   
sSiteURL = value; n# FkgXP$  
} ._.Qf<7  
Yb:F,d-Ya  
/7-FVqDx8  
public String getSFilePath() `)BZk[64  
{ 9wdX#=I  
return sFilePath; t0^)Q$  
} _u~`RlA  
scrss  
izu_KBzy  
public void setSFilePath(String value) rDc$#  
{ c/(Dg$DbX  
sFilePath = value;  (8 /&  
} !!~r1)zN  
N Zwi3  
MOuEsm;  
public String getSFileName() O8LIKD_I[  
{ D8$4PT0u  
return sFileName; $?pfst~;O  
} ykGA.wo7/P  
Ffd;aZ4n  
]XYD2fR2qA  
public void setSFileName(String value) Emk:@$3{r  
{ w`zS`+4  
sFileName = value; UyDq`@h  
} }5B\:*yW  
koj*3@\p/  
gf/<sH2}  
public int getNSplitter() fA), ^  
{ /\E3p6\*  
return nSplitter; nD=N MqQ &  
} =%b1EY k  
.j"@7#tW  
LftGA7uGJ)  
public void setNSplitter(int nCount) zq|NltK  
{  ]l  
nSplitter = nCount; SUsdX[byb  
} _0Y?(}  
} bhfC2@  
TEC#owz  
}rWg ']  
/* DMKtTt[}  
**Utility.java JDO n`7!w  
*/ Z)}2bJwA  
package NetFox; 0}g~69Z1=  
T?7++mcA  
t\n'Kuk`  
public class Utility { 2>Qy*  
[X@JH6U r  
DJ!pZUO{  
public Utility() Pup%lO`.0  
{ =n8M'  
X*&Thmee  
;i ?R+T  
} ~/2OK!M  
B}N1}i+  
//线程睡眠 IPt !gSp  
public static void sleep(int nSecond) z|$9%uz"  
{ FY/F}C,o  
try{ U8<C4  
Thread.sleep(nSecond); s/P+?8'9  
} cSmy M~[  
catch(Exception e) iaRCV 6cl  
{ "Sw raq  
e.printStackTrace (); GX*9R>  
} r<Q0zKW!jN  
} pK0@H"$8  
LFvZ 7M\\  
//日志 9)4_@rf%  
public static void log(String sMsg)  jQ-2SA O  
{ +Y>oNX1KN  
System.err.println(sMsg); ]y"=/Nu-Ja  
} .P ??N  
8,&Y\b`..  
 C8} ;,  
public static void log(int sMsg) O! _d5r&,  
{ KNOVb=# f_  
System.err.println(sMsg); 2M+ *VO  
} va0}?fy.O%  
} VWqZ`X  
wv Mp~  
+HG*T[%/  
/* P4 #j;k4P  
**TestMethod.java KD- -w(4  
*/ `A8ErfA  
package NetFox; 2{B ScI5K  
iMQ0Sq-%1  
(N`GvB7;  
public class TestMethod { 4Ujy_E?^  
ej \S c7.  
Epm8S}6K  
public TestMethod() #IU^(W  
{ ///xx/weblogic60b2_win.exe 6S0Gjekr  
try{ y8} /e@&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); c Ze59  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); kX+98?h-C  
SiteFileFetch fileFetch = new SiteFileFetch(bean); aF>&X-2  
fileFetch.start(); 9VSi2p*  
} 'p[B`Ft3F  
catch(Exception e){e.printStackTrace ();} \[ 4y  
=uR3|U(.|u  
(]zi;  
} -oB=7+g  
@0 [^SU?  
Dd:^ {  
public static void main(String[] args) $  k_6  
{ @\W-=YKLg  
new TestMethod(); NnaO!QW%  
} K@ a#^lmd  
} xT!<x({  
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