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http断点续传简单实现(java)

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/* ePq(.o  
**SiteFileFetch.java Z{t `f[  
*/ Oc,HnyV+  
package NetFox; OVxg9  
import java.io.*; 0$b4\.0>~  
import java.net.*; UlNiH  
<5Ll<0  
MGK?FJn_?  
public class SiteFileFetch extends Thread { %TAS4hnu%  
,o0Kevz  
kVCWyZh4  
SiteInfoBean siteInfoBean = null; //文件信息Bean T12Zak4.=  
long[] nStartPos; //开始位置 B1Pi+-t  
long[] nEndPos; //结束位置 LPs5LE[Pm  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 o\><e1P  
long nFileLength; //文件长度 :+w6i_\d5  
boolean bFirst = true; //是否第一次取文件 2~QJ]qo=  
boolean bStop = false; //停止标志 db_}][;.c  
File tmpFile; //文件下载的临时信息 Y~!A"$   
DataOutputStream output; //输出到文件的输出流 1he5Zevm}  
v>nBdpjXh  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) rtbV*@Z  
public SiteFileFetch(SiteInfoBean bean) throws IOException p(="73  
{ _E8Cvaob  
siteInfoBean = bean; :.=j)ljTx  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eU`O=uE   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @(*A<2;N  
if(tmpFile.exists ()) 3P>1-=  
{ Dk$<fMS,7c  
bFirst = false; @vib54G  
read_nPos(); ?7lW@U0  
} oa=TlBk<  
else *_J{_7pwe  
{ _<F;&(o  
nStartPos = new long[bean.getNSplitter()]; N^wHO<IO 1  
nEndPos = new long[bean.getNSplitter()]; =j~:u.hc'  
} o%`=+- K  
'Q 7^bF^  
8sBT&A6&j  
,uNJz-B8  
} dIh+h|:  
g]N'6La  
tcRJ1:d  
public void run() cX4]ViXSr  
{ K1R?Qt,qDF  
//获得文件长度 9c*B%A8J  
//分割文件 dHg[r|xC  
//实例FileSplitterFetch  Pw +nO  
//启动FileSplitterFetch线程 .#iot(g  
//等待子线程返回  /d!  
try{ Og@{6>  
if(bFirst) $`%Om WW{  
{ NOkgG0Z  
nFileLength = getFileSize(); ~b X~_\  
if(nFileLength == -1) .}Xf<G&  
{ G3]#Du  
System.err.println("File Length is not known!"); Nmt~1.J  
} 5a@9PX^.J  
else if(nFileLength == -2) ~Mar  
{ W#^.)V  
System.err.println("File is not access!"); KZcmNli&A  
} r_,;[+!  
else `jr?I {m;  
{ Ya!%o> J%t  
for(int i=0;i<nStartPos.length;i++) D*PEIsV  
{ m__pQu:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l1O"hd'~s  
} o[WDPIG  
for(int i=0;i<nEndPos.length-1;i++) Z zp"CK 5  
{ eV(9I v[  
nEndPos = nStartPos[i+1]; uifVSf*  
} ,LSiQmV5  
nEndPos[nEndPos.length-1] = nFileLength; 4$ihnb`DQN  
} 34N~<-9AY  
} wYV>Qd Z  
uPYH3<  
3Z me?o*bY  
//启动子线程 f{[0;qDJ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; liLhvcd  
for(int i=0;i<nStartPos.length;i++) %m[ZU<v  
{ hOj+z?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f^"pZS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), f.66N9BHL,  
nStartPos,nEndPos,i); :-Py0{s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dVHbIx  
fileSplitterFetch.start(); R1w5,Zt  
} rMZuiRz*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B@6L<oZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g*LD}`X/-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8 Zp^/43  
nEndPos = " + nFileLength); b8YdONdy  
// fileSplitterFetch[nPos.length-1].start(); Kdp($L9r  
G-RDQ  
3/ }  
//等待子线程结束 Qr7v^H~E4.  
//int count = 0; XG C\6?L~  
//是否结束while循环 vDi Opd  
boolean breakWhile = false; q-_!&kDK"  
^->S7[N?  
"&4r!2A  
while(!bStop) :E~rve'  
{ #RU8 yT  
write_nPos(); m~Q24Z]!'&  
Utility.sleep(500); NT5'U  
breakWhile = true; j4 #uj[A  
Sx e6&  
Qs59IZ  
for(int i=0;i<nStartPos.length;i++) !d!u{1Y&  
{ vW vu&3tx  
if(!fileSplitterFetch.bDownOver) DU]KD%kl  
{ qdv O>k3  
breakWhile = false; A%$~  
break; $8HiX6r  
} blIMrP%  
} '/@wk#,  
if(breakWhile) k>.8lc\  
break; 9:VUtx#}2  
8 p[n>qV9  
|}UkVLc_^  
//count++; \( #"g  
//if(count>4) #eJ<fU6Da  
// siteStop(); V(DY!f_%  
} j4!O,.!T  
;`:YZ+2 Z  
1,bE[_  
System.err.println("文件下载结束!"); zhFm2  
} 7dACbqba  
catch(Exception e){e.printStackTrace ();} pb)8?1O|s  
} (?JdiY/  
Z f\~Cl  
fC*cqc~{@  
//获得文件长度 -,p=;t#(  
public long getFileSize() ZcyGLg0I  
{ \i%mokfbc  
int nFileLength = -1; (4A'$O2  
try{ je2_ .^  
URL url = new URL(siteInfoBean.getSSiteURL()); W [K.|8ho  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]6)u$4X6$  
httpConnection.setRequestProperty("User-Agent","NetFox"); Jut&J]{h  
u YT$$'S  
` K {k0_{  
int responseCode=httpConnection.getResponseCode(); ';/J-l/SE  
if(responseCode>=400) 0Q_*Z (  
{ /YF:WKr2  
processErrorCode(responseCode); 'D ?o^  
return -2; //-2 represent access is error oR=i5lAU  
} c AEvv[  
rHX^bcYK  
B<m0YD?>~>  
String sHeader; 0zq'Nf?#3  
S\&3t}_  
`;;l {8  
for(int i=1;;i++) %g.cE}^  
{ uy3<2L#.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wAprksZL#  
//Utility.log(in.readLine()); &gY) x{  
sHeader=httpConnection.getHeaderFieldKey(i); #Q^" .#  
if(sHeader!=null) }a6t<m`V  
{ VoZ{I{>|  
if(sHeader.equals("Content-Length")) qVE0[ve  
{ ~RuX2u-2&u  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c!4F0(n4  
break; #[lhem]IC  
} G!r)N0?_f  
} &R_7]f+%)  
else Q]xkDr?   
break; \BXzmok  
} +C{-s  
} eNAxVF0  
catch(IOException e){e.printStackTrace ();} ?s^3 o{!<W  
catch(Exception e){e.printStackTrace ();} TD}<U8I8_  
'YNdrvz  
1" cv5U  
Utility.log(nFileLength); 1w^wa_qx  
fj5 g\m  
X&qx4 DL  
return nFileLength; k*hl"oL"X  
} lZcNio  
UPfO;Z`hJ  
s.}K?)mH  
//保存下载信息(文件指针位置) \7/yWd{N$  
private void write_nPos() U+)p'%f;  
{ y3dk4s77  
try{ `)n4I:)2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Pj-INc96  
output.writeInt(nStartPos.length); \@:,A]  
for(int i=0;i<nStartPos.length;i++) YS9RfK/  
{ NFs5XpZ~  
// output.writeLong(nPos); N"ga -u  
output.writeLong(fileSplitterFetch.nStartPos); ;Y`Y1  
output.writeLong(fileSplitterFetch.nEndPos); .Q*X5Fc  
} [s {!  
output.close(); St-uE |8  
} y!77gx?-  
catch(IOException e){e.printStackTrace ();} A]/o-S_  
catch(Exception e){e.printStackTrace ();} { :tO RF  
} @dDeOnF  
pFd8p@m_2  
"n!yK  
//读取保存的下载信息(文件指针位置) ;"wCBuXcu  
private void read_nPos() i/ilG 3m>  
{ _6ZjF>f  
try{ LmF,en5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \beO5]KS<  
int nCount = input.readInt(); C8}:z\A_@Z  
nStartPos = new long[nCount]; !LI<%P)  
nEndPos = new long[nCount]; :jLL IqhB  
for(int i=0;i<nStartPos.length;i++) q!5:M\  
{ %SM;B-/zHt  
nStartPos = input.readLong(); +J X;T(T  
nEndPos = input.readLong(); g\JJkXjD#  
} @LKQ-<dZG  
input.close(); (CmK> "C+  
} >M,oyM" s  
catch(IOException e){e.printStackTrace ();} $RaN@& Wm  
catch(Exception e){e.printStackTrace ();} *glZb;_  
} +$,Re.WnP  
O<gfZ>  
k&]nF,f  
private void processErrorCode(int nErrorCode) Z',!LK!  
{ Ma[EgG  
System.err.println("Error Code : " + nErrorCode); &7aWVKon  
} ^/2I)y]W0  
S\e&xUA;|  
xAQtX=FoX+  
//停止文件下载 C9 n%!()>  
public void siteStop() 7~/cz_  
{ %z><)7  
bStop = true; iQwQ5m!d &  
for(int i=0;i<nStartPos.length;i++) Eah6"j!B8n  
fileSplitterFetch.splitterStop(); OU[<\d  
*U?O4E9  
wHc my  
} HGDrH   
} l90mM'[  
//负责部分文件的抓取 200yN+ec  
**FileSplitterFetch.java ~U9K<_U  
*/ 'ZfgCu)St  
package NetFox; Ey46JO"  
2@&r!Q|1vR  
|\5^ub,m  
import java.io.*; g`7XE  
import java.net.*; "F<CGSo  
BX,)G HE  
!'7fOP-J]  
public class FileSplitterFetch extends Thread { #%0V`BS7n  
~C.*Vc?|  
l4Xz r:]  
String sURL; //File URL rl*O-S/  
long nStartPos; //File Snippet Start Position Ifj&S'():  
long nEndPos; //File Snippet End Position O !L`0 =%c  
int nThreadID; //Thread's ID VM"cpC_8  
boolean bDownOver = false; //Downing is over *Z5^WHwg  
boolean bStop = false; //Stop identical [VCC+_  
FileAccessI fileAccessI = null; //File Access interface yPm2??5MW>  
/Rp]"S vt  
[I $+wWW_  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _FLEz|%~  
{ ^.SYAwL  
this.sURL = sURL; C_.9qo]DT7  
this.nStartPos = nStart; ]b/]^1-(b  
this.nEndPos = nEnd; )*,/L <  
nThreadID = id; @ D+ftb/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 gV_/t+jI  
} ^u /%zL  
a^|DD#5  
_]Hna<Ly  
public void run() g*| j+<:7  
{ (B7G'h.?  
while(nStartPos < nEndPos && !bStop) 7io["zW  
{ i=8iK#2 h  
@=Kq99=\U  
}{aGh I~<  
try{ Lpchla$  
URL url = new URL(sURL); pJpapA2l*6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jcH@*c=%e  
httpConnection.setRequestProperty("User-Agent","NetFox"); .1x04Np!  
String sProperty = "bytes="+nStartPos+"-"; ^rkKE dd  
httpConnection.setRequestProperty("RANGE",sProperty); PxHFH pL  
Utility.log(sProperty); pMc6p0  
fCl}eXg6w  
]Z JoC!u  
InputStream input = httpConnection.getInputStream(); XC4Z,,ah"  
//logResponseHead(httpConnection); ,g`%+s7u  
c}x1-d8  
YdY-Jg Xm  
byte[] b = new byte[1024]; )&DAbB!O  
int nRead; h`fVQN.3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) CUA @CZ6{  
{ mYBEjZ B  
nStartPos += fileAccessI.write(b,0,nRead); /'O8RUjN  
//if(nThreadID == 1) ^ k^y|\UtZ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T) C@6/  
} BxY t*b%  
$EMOz=)I#  
s:`i~hjq  
Utility.log("Thread " + nThreadID + " is over!"); 85{m+1O~  
bDownOver = true; <_tmkLeZf  
//nPos = fileAccessI.write (b,0,nRead); G4&s_ M$  
} DA =U=F  
catch(Exception e){e.printStackTrace ();} prBLNZp  
} J3Mb]X)_}  
} e5 =d Ev  
<t%gl5}|  
wN 2+3LY{  
//打印回应的头信息 (z?HyxRT  
public void logResponseHead(HttpURLConnection con) ]' mbHkn68  
{ \ /-c)  
for(int i=1;;i++) .J#'k+>  
{ aD/Rr3v>  
String header=con.getHeaderFieldKey(i); LzygupxY!  
if(header!=null) ^\)a[OWp  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); HDyf]2N*N  
Utility.log(header+" : "+con.getHeaderField(header)); bP,<^zA|X  
else ]AP1+ &9fN  
break; GnV0~?  
} Pg4&}bX:I  
} ,CO2d)}  
vG&>- Z  
yev!Nw  
public void splitterStop() Vla,avON  
{ X/]@EF  
bStop = true; C2LPLquD+  
} ~PQ.l\C  
NGra/s,9 |  
~{c ?-qb  
} ]5W$EvZ9)  
lwnO  
}ze+ tf  
/* XLpP*VH3  
**FileAccess.java [)H 6`w  
*//文件访问(定位,写) ! \] ^c  
package NetFox; #GsOE#*>T  
import java.io.*; SpH|<L3  
4Nm>5*]  
\lL[08G  
public class FileAccessI implements Serializable{ !+x Q  
?}||?2=P  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 SNEhP5!  
RandomAccessFile oSavedFile; J5@08 bZm  
long nPos; pA7-B>Y  
<Ij!x`MS+  
5'lVh/  
public FileAccessI() throws IOException K/4@ 2vF  
{ ^ 5 >e  
this("",0); U}v`~' K  
} 2:+8]b3i  
2 a<\4w'  
3WV(Ok  
public FileAccessI(String sName,long nPos) throws IOException ycGY5t@K@  
{ |9@,ri\'Rg  
oSavedFile = new RandomAccessFile(sName,"rw"); 0SpB 2>_  
this.nPos = nPos; h!"2Ux3!x  
oSavedFile.seek(nPos); 8K8u|]i  
} 3 qYGEhxv  
Z[vx0[av&  
 ` Xc7b  
public synchronized int write(byte[] b,int nStart,int nLen) D?|D)"?qb  
{ hW7u#PY  
int n = -1; 9O[IR)O~  
try{ :]"5UY?oF  
oSavedFile.write(b,nStart,nLen); OY*y<>  
n = nLen; 4^_6~YP7  
} BU nujC  
catch(IOException e) ,5'o>Y  
{  <,.$U\W  
e.printStackTrace (); D(cD8fn,J  
} p l)":}/)  
1- RY5R}VR  
za l]t$z>  
return n; IrwQ~z3I  
} y@LImiRG  
^[ae )}  
{9IRW\kn  
} W5j wD  
>OG189O  
z%&FLdXgW+  
/* o$_0Qs$  
**SiteInfoBean.java /SvhOi  
*/ g`EZLDjt  
package NetFox; w0QtGQ|  
rcnH^P  
_K5<)( )  
public class SiteInfoBean { 2w>%-_]u+  
W 4{ T<  
ET*A0rt  
private String sSiteURL; //Site's URL .[={Yx0!I  
private String sFilePath; //Saved File's Path Po>6I0y  
private String sFileName; //Saved File's Name SA, ~q&  
private int nSplitter; //Count of Splited Downloading File t@KTiJI ]  
q|5WHB  
K5>3  
public SiteInfoBean() eAHY/Y!  
{//nSplitter的缺省值为5 5!0iK9O  
//default value of nSplitter is 5 /08FV|tX)  
this("","","",5); 2:LUB)&i  
} %$BRQ-O  
7uBx  
j }~?&yB  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {uDW<u_!  
{ 8lQ/cGAc  
sSiteURL= sURL; hzD)yf  
sFilePath = sPath; XY0kd&N8  
sFileName = sName; ;W0J  
this.nSplitter = nSpiltter; 0'&C5v'  
g%2G=gR$?z  
'afW'w@  
} m:_#kfC&K"  
v[CR$@Y  
G<Z}G8FW^  
public String getSSiteURL() \Z*:l(  
{ jAQ{H  
return sSiteURL; zK0M WyXO  
} %PW-E($o<  
:?f<tNU$  
k|fM9E  
public void setSSiteURL(String value) 5 nt3gVy  
{ 1q}32^>+o  
sSiteURL = value; +\dVC,,=^g  
} $G=^cNB|JB  
C&O8fNB_  
AArLNXzVW  
public String getSFilePath() l&& i`  
{ 3h bHS~  
return sFilePath; >WHajYO"  
} v}>g* @  
+=WBH'  
8~y!X0Ov!  
public void setSFilePath(String value) 6Ga'_P:  
{ lw=kTYbq  
sFilePath = value; ueg%yvO  
} \Y xG  
l@Lk+-[D  
+m_ .?V6  
public String getSFileName() o HK   
{ HB9"T5Pd*  
return sFileName; &0 QUObK  
} `(W"wC   
F"Dr(V  
8%4;'[UV  
public void setSFileName(String value) Y58H.P  
{ 5%'ybh)@   
sFileName = value; 74_?@Z(  
} 2d[tcn$;h]  
_ $PeFE2  
4'faE="1)S  
public int getNSplitter() Fd8nR9A  
{ d /jx8(0  
return nSplitter; 33` bKKO}  
} P IG,a~  
U=v>gNba  
>A )Sl'  
public void setNSplitter(int nCount) $GoS?\G  
{ j ,rc9  
nSplitter = nCount; 8;M,l2pmR{  
} \t{iyUxY  
} Jq1oQu|rs  
5|0}bv O  
n3e,vP? R  
/* /G5KNSi  
**Utility.java 8] LF{Obz[  
*/ _d!sSyk`  
package NetFox; 5?3v;B6  
E2Sj IR}  
CW;zviH5  
public class Utility { CfOyHhhKX  
X8}r= K~  
l(Y32]Z   
public Utility() c| %5SA  
{ 2tU3p<[  
S5|7D[*  
:F d1k Jm  
} TT/=0^"  
&"u(0q  
//线程睡眠 7Kym|Zg  
public static void sleep(int nSecond) 7$7|~k  
{ !19T=p/:$  
try{ -cUW,>E  
Thread.sleep(nSecond); 3 EAr=E]  
} JP!e'oWxi  
catch(Exception e) ln<[CgV8  
{ /5%'q~  
e.printStackTrace (); 2k!uk6  
} u%L6@M2  
} Wz^;:6F  
oD%n}  
//日志 QeY+imM  
public static void log(String sMsg) ~N /%R>(v  
{ Sh;`<Ggi~  
System.err.println(sMsg); %X\J%Fj  
} QM!UMqdj  
yS)k"XNb  
wgDAb#Zuk  
public static void log(int sMsg) i<&z'A6&]*  
{ *7*_QW%?A  
System.err.println(sMsg); eDo4>k"5  
} QVn2`hr  
} }P=FMme{F(  
-/3h&g  
lBn<\Y!^  
/* !B[ Y?b:  
**TestMethod.java e_Zs4\^ef  
*/ C&F% j.<  
package NetFox; kFJ]F |^7  
oCwep^P(v  
;E}&{w/My  
public class TestMethod { x ~l"'qsK  
e?\Od}Hbw  
0#c-qy  
public TestMethod() 1`II%mf[  
{ ///xx/weblogic60b2_win.exe SdufI_'B  
try{ AU*]D@H  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ldG8hK  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); HJr*\%D}1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); MPp:EH  
fileFetch.start(); ( *26aMp  
} YTgT2w  
catch(Exception e){e.printStackTrace ();} vU/sQt8  
qHrIs-NR  
5m;pHgkb  
} [)Ia Xa  
"6e3Mj\  
1>_$O|dE  
public static void main(String[] args) -8:O?]+Q/  
{ tIA)LF  
new TestMethod(); lYS4Q`z$  
} q q^[(n  
} u 'ng'j'  
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