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http断点续传简单实现(java)

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/* LiC*@W  
**SiteFileFetch.java ;V:i!u u  
*/ &&5aM  
package NetFox; )!th7sH  
import java.io.*; 0cv{  
import java.net.*; g+8OekzB5  
du $:jN\}  
4qb/da E:Z  
public class SiteFileFetch extends Thread { SXSgld2uS  
I13y6= d  
a=|K%ii+Y  
SiteInfoBean siteInfoBean = null; //文件信息Bean j2t7'bO_  
long[] nStartPos; //开始位置 e@L=LW>  
long[] nEndPos; //结束位置 @+&LYy72  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x 77*c._3v  
long nFileLength; //文件长度 !{+,B5 Hc  
boolean bFirst = true; //是否第一次取文件 yJ[0WY8<kC  
boolean bStop = false; //停止标志 QGMV}y  
File tmpFile; //文件下载的临时信息 JinUV6cr  
DataOutputStream output; //输出到文件的输出流 \0^Kram>  
70 yFaW  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) fF!Yp iI"  
public SiteFileFetch(SiteInfoBean bean) throws IOException h/QXPdV  
{ qJf?o.Pv  
siteInfoBean = bean; po c`q5i+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -mbt4w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); w1F cB$  
if(tmpFile.exists ()) +r�  
{ u4*BX&  
bFirst = false; 3<e=g)F  
read_nPos(); Yj<a" Gr4[  
} k90YV(  
else bt@< ut\  
{ vO H4#  
nStartPos = new long[bean.getNSplitter()]; XnH05LQ  
nEndPos = new long[bean.getNSplitter()]; 3p$?,0ELH  
} i7CX65&b  
u%GEqruo[  
%HhBt5w  
,5P0S0*{  
} +N]J5Ve-`t  
+WZX.D  
k`cfG\;r  
public void run() Gf%~{@7=u  
{ 1>.Ev,X+e  
//获得文件长度 V%t.l  
//分割文件 DcS+_>a\{l  
//实例FileSplitterFetch lwR<(u31e  
//启动FileSplitterFetch线程 ]]HNd7Vh  
//等待子线程返回 ,=uD^n:  
try{ W Tcw4  
if(bFirst) ;_XFo&@  
{ h! ,v/7=  
nFileLength = getFileSize(); ;gD})@  
if(nFileLength == -1) %6t:(z  
{ ./XYd"p  
System.err.println("File Length is not known!"); Ml`:UrU  
} ;'gWu  
else if(nFileLength == -2) cQjv$$&6[  
{ +Z,;,5'5G  
System.err.println("File is not access!"); '"52uZ{  
} QDZWX`qw{  
else m%0p\Y-/  
{ I<DL=V  
for(int i=0;i<nStartPos.length;i++) Mg+2. 8%  
{ YByLoM*  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +l42Awl>K  
} .S EdY:  
for(int i=0;i<nEndPos.length-1;i++) V_)-#=J  
{ ),_@WW;k  
nEndPos = nStartPos[i+1]; uIY#e<)}G  
} n5|fHk^s  
nEndPos[nEndPos.length-1] = nFileLength; ]|#+zx|/D  
} "BAK !N$9  
} g9OY<w5s]  
BqEI(c 6  
r[e##M  
//启动子线程 (xycJ`N  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?C]vS_jAh  
for(int i=0;i<nStartPos.length;i++) 6dHOf,zjm  
{ pG_;$8Hc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k``_EiV4t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), pt?bWyKG  
nStartPos,nEndPos,i); R- X5K-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]43/`FX  
fileSplitterFetch.start(); L]7=?vN=8  
} />C^WQI^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +8T?{K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "%)qRe  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \Zk;ikEY  
nEndPos = " + nFileLength); cUk7i`M;6  
// fileSplitterFetch[nPos.length-1].start(); `Uq#W+r,  
D#aDv0b  
b\f O8{k  
//等待子线程结束 #x@$ lc=k3  
//int count = 0; oueC  
//是否结束while循环 ]dVGUG8  
boolean breakWhile = false; 4>YR{  
]U?^hZ_  
<(#(hDwy  
while(!bStop) 0J*??g-n  
{ *YI98  
write_nPos(); yHYsZ,GE  
Utility.sleep(500); . P viA  
breakWhile = true; I]|Pq  
oE @a'*.\  
; T\%|O=Ke  
for(int i=0;i<nStartPos.length;i++)  OHN_  
{ RIR\']WN  
if(!fileSplitterFetch.bDownOver) _1X!EH"  
{ q$L%36u~/  
breakWhile = false; '$Dn  
break; 2 B1q*`6R  
} P.se'z)E  
} 85= )lu  
if(breakWhile) rCEyQ)R_}  
break; !"AvY y9  
m~BAyk^jo3  
TJd)K$O>  
//count++; Xxj- 6i  
//if(count>4) 8bGd} (  
// siteStop(); %X]jaX 7  
} thh. A  
R>|{N9  
Ng&%o  
System.err.println("文件下载结束!"); ejKucEgD  
}  ,i NXK  
catch(Exception e){e.printStackTrace ();} @ )F)S 7  
} eSn+B;  
Vsr.=Nd=  
5PCqYN(:B  
//获得文件长度 `?H]h"{7Q  
public long getFileSize() -]Bq|qTH[(  
{ (M|Dx\_  
int nFileLength = -1; =HK!(C  
try{ zC:ASt  
URL url = new URL(siteInfoBean.getSSiteURL()); b)#hSjWO#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -:^U_FL8un  
httpConnection.setRequestProperty("User-Agent","NetFox"); n)/z0n!\  
ZmqKQO  
QpH'PYy  
int responseCode=httpConnection.getResponseCode(); W-f=]eWg  
if(responseCode>=400) Z3e| UAif  
{ uh_RGM&  
processErrorCode(responseCode); *tFHM &a  
return -2; //-2 represent access is error C.:<-xo  
} u]wZQl#-  
.8g)av+  
~%F9%=  
String sHeader; !.$I["/=  
9)yJ: N#F  
.~db4d]  
for(int i=1;;i++) KM0ru  
{ L< S9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wo}H'Q}Hj  
//Utility.log(in.readLine()); }v;V=%N+v  
sHeader=httpConnection.getHeaderFieldKey(i); ~G p [_ %K  
if(sHeader!=null) yf)%%&  
{ UXz<)RvB  
if(sHeader.equals("Content-Length")) Mexk~z A^  
{ ;a!S!% .h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); P{`C^W$J^  
break; M7\szv\Zc=  
} fm%t^)E  
} A|[?#S((]  
else @u+]aI!`-  
break; FZ QP%]FX  
} r r %V.r;2  
} G>_*djUf  
catch(IOException e){e.printStackTrace ();} 2szPAuN+  
catch(Exception e){e.printStackTrace ();} lBE= (A`  
H'5)UX@LP  
eIF5ZPSZi  
Utility.log(nFileLength); "!P3R1;%  
%`r$g[<G  
5pG}Yk_(x  
return nFileLength; tFn)aa~L  
} n80?N}  
JG. y,<xW  
g axsv[W>^  
//保存下载信息(文件指针位置) +^ac'Y)A  
private void write_nPos() P:S.~Jq  
{ A  'be8  
try{ @s&71a  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q}JOU  
output.writeInt(nStartPos.length); 2W(s(-hD  
for(int i=0;i<nStartPos.length;i++) m 0C@G5  
{ X0 5/uX{  
// output.writeLong(nPos); h&iC;yj=  
output.writeLong(fileSplitterFetch.nStartPos); P5V}#;v  
output.writeLong(fileSplitterFetch.nEndPos); 6wRd<]C  
} K3&qq[8.e  
output.close(); s[*rzoA  
} #zy :a%  
catch(IOException e){e.printStackTrace ();} Es`Px_k  
catch(Exception e){e.printStackTrace ();} Wb_J(!da  
} ~_)^X  
@;4zrzQi7  
<}Vrl`?h  
//读取保存的下载信息(文件指针位置) 7+cO_3AB  
private void read_nPos() C& f= ywi0  
{ s^TZXCyF o  
try{ Wi<m{.%\E  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =s{>Fsm1  
int nCount = input.readInt(); AN m d!  
nStartPos = new long[nCount]; >uB?rGcM  
nEndPos = new long[nCount]; CW K7wZM  
for(int i=0;i<nStartPos.length;i++) P;no?  
{ Q*cf(  
nStartPos = input.readLong(); 2.y-48Nz  
nEndPos = input.readLong(); dQX6(J j  
} 59L\|OR  
input.close(); v~C Czg  
} :4w ?#  
catch(IOException e){e.printStackTrace ();}  A@('pA85  
catch(Exception e){e.printStackTrace ();} 3&4(ZH=  
} S+6.ZZ9c  
M0"_^?  
{ uFO/  
private void processErrorCode(int nErrorCode) Qljpx?E  
{ V &T~zh1  
System.err.println("Error Code : " + nErrorCode); MJ)RvNF  
} D) P._?  
W i.& e  
VGN5<?PrN  
//停止文件下载 UDFDJm$  
public void siteStop() (,2S XV  
{ h" W,WxL8  
bStop = true; A{zN | S[  
for(int i=0;i<nStartPos.length;i++) (mB&m@-N  
fileSplitterFetch.splitterStop(); |-ALklXr  
Rv>-4@fMJ  
Q{>k1$fkV  
} Yh7t"=o  
} KF}hV9IU  
//负责部分文件的抓取 Dy&i&5E.-l  
**FileSplitterFetch.java Nx;~@  
*/ ~8+ Zs  
package NetFox; @ q3k%$4  
o/)h"i0P  
JR|ck=tq  
import java.io.*; 1&OW4_  
import java.net.*; HJH{nz'Lw  
RB\uK 1+  
>:!5*E5?  
public class FileSplitterFetch extends Thread { _f,C[C[e&  
({_{\9O,3  
6@!`]tSCK  
String sURL; //File URL T>Z<]s  
long nStartPos; //File Snippet Start Position 0mVNQxHI  
long nEndPos; //File Snippet End Position |r/"  |`  
int nThreadID; //Thread's ID V0YZp  
boolean bDownOver = false; //Downing is over Fo_sgv8O<  
boolean bStop = false; //Stop identical H?Wya.7  
FileAccessI fileAccessI = null; //File Access interface gQuw1  
J;e2&gB  
C) s5D  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0+ '&`Q!u  
{ 5tk AFb4P  
this.sURL = sURL; =qIp2c}Rx  
this.nStartPos = nStart; B$K=\6o  
this.nEndPos = nEnd; Q&;9 x?e  
nThreadID = id; ?V=ZIGj  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (t|Zn@uY  
} w9imKVry  
*^4"5X@  
n>XdU%&  
public void run() <lPG=Xt  
{ V!=,0zy~Z  
while(nStartPos < nEndPos && !bStop) q;CiV  
{ A)!*]o>U  
`h\j99  
J@'wf8Ub  
try{ "S]TP$O D  
URL url = new URL(sURL); )&O %*@F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3 i0_hZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); BWrxunHO  
String sProperty = "bytes="+nStartPos+"-"; BU_nh+dF  
httpConnection.setRequestProperty("RANGE",sProperty); AT3Mlz~7#  
Utility.log(sProperty); tNI^@xdim1  
 8nJpp  
cT,sh~-x,  
InputStream input = httpConnection.getInputStream(); m(!FHPvN  
//logResponseHead(httpConnection); Fxz"DZY6  
cq]6XK-W  
~ 7s!VR  
byte[] b = new byte[1024]; q9_OGd|P  
int nRead; * u>\57W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o.!Dq7 R  
{ \b x$i*  
nStartPos += fileAccessI.write(b,0,nRead); 2ilQXy  
//if(nThreadID == 1) ~0$&3a<n1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FZlWsp=  
} oc`H}Wvn  
F41=b4/  
3 0H?KAV  
Utility.log("Thread " + nThreadID + " is over!"); ,"ZMRq  
bDownOver = true; oPM96 (  
//nPos = fileAccessI.write (b,0,nRead); EQM {  
} 7NGxa6wi  
catch(Exception e){e.printStackTrace ();} `;C  V=,M  
} 5;EvNu  
} L4HI0Mx  
/4Gt{yg Sr  
jL luj   
//打印回应的头信息 R/YqyT\SM  
public void logResponseHead(HttpURLConnection con) 5]0 <9a  
{ %h@EP[\  
for(int i=1;;i++) &8lZNv8;(p  
{ e"<OELA  
String header=con.getHeaderFieldKey(i); L0o\J` :  
if(header!=null) GTd,n=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .k !{*  
Utility.log(header+" : "+con.getHeaderField(header)); {wKB;?fUvk  
else {<KVx9  
break; K"MX!  
} ]a`$LW}  
} (9a^$C*  
4Nsp<Kn>  
*EH~_F  
public void splitterStop() 1qA;/-Zr<o  
{ M= (u]%\  
bStop = true; !Uo4,g6r+  
} ygcm|PrS  
MQ2}EY*A  
upmx $H>  
} mfr|:i  
y9ZvV0  
!a\^Sk /  
/* 75lA%| *X  
**FileAccess.java N!}f}oF  
*//文件访问(定位,写) %N._w!N<5n  
package NetFox; 6gDN`e,@  
import java.io.*; {Sh ;(.u^  
W>r+h-kR  
;$4\e)AB  
public class FileAccessI implements Serializable{  RRJ%:5&  
L/K(dkx  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 e0 ecD3  
RandomAccessFile oSavedFile; UN#S;x*  
long nPos; TWTb?HP  
?@x/E&  
0y\Z9+G:  
public FileAccessI() throws IOException * ;FdD{+  
{ }GM'.yutX  
this("",0); DEgXQ[  
} LghfM"g  
u ga_T  
6u6x  
public FileAccessI(String sName,long nPos) throws IOException A#,ZUOPGH  
{ ;'1d1\wiDQ  
oSavedFile = new RandomAccessFile(sName,"rw"); V7/Rby Q  
this.nPos = nPos; xE}>,O|'q  
oSavedFile.seek(nPos); 8ao_i=&x  
} UiNP3TJ'L  
* T1_;4i  
{!`6zBsP  
public synchronized int write(byte[] b,int nStart,int nLen) #vlgwA  
{ lOp`m8_=  
int n = -1; %C]>9."  
try{ Fr-SvsNFB  
oSavedFile.write(b,nStart,nLen); 7tp36TE  
n = nLen; l[J8!u2Xp  
} 4,ag(^}=  
catch(IOException e) zt%Mx>V@  
{ WIGi51yC.x  
e.printStackTrace (); r JB}qYD  
} 9gIrt 6  
6]wIG$j  
,esmV-  
return n; ar,7S&s H  
} \U_@S.  
eO1lnO|  
 !VpoZ  
} t{>q|0  
-?a 26o%e  
]M3yLYK/P  
/* k?}Zg*  
**SiteInfoBean.java dh\P4  
*/ =(^3}x  
package NetFox; mE[y SrV  
V]^$S"Tv  
I-)4YQI  
public class SiteInfoBean { HaYo!.(Fv  
;*J  
xSu >  
private String sSiteURL; //Site's URL B5QFK  
private String sFilePath; //Saved File's Path 5V-I1B&  
private String sFileName; //Saved File's Name wIgS3K  
private int nSplitter; //Count of Splited Downloading File Bw.i}3UT6  
Ys7]B9/1O  
73-p*o(pt  
public SiteInfoBean() q(w(Sd)#L  
{//nSplitter的缺省值为5 X>^fEQq"  
//default value of nSplitter is 5 "N#Y gSr  
this("","","",5); ^zr`;cJ+c  
} i30!}}N8  
pCG}Z Ka  
wC*X4 '  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) i/.6>4tE:  
{ lq uLT6]  
sSiteURL= sURL; A}!J$V:w]  
sFilePath = sPath; HOi`$vX }N  
sFileName = sName; TA\vZGJ('  
this.nSplitter = nSpiltter; $~kA B8z  
W*G<X.Hf  
{`_i`  
} + T+#q@  
|y*c9  
Rb;'O89Hj@  
public String getSSiteURL() F"kAkX>3}  
{ zm#  ?W  
return sSiteURL; 3g B7g'U  
} `0svy}  
/kG_*>.Z  
/_.|E]  
public void setSSiteURL(String value) IGgL7^MF  
{ )5H?Vh>36  
sSiteURL = value; Fzcwy V   
} }0 ?3:A  
iDD$pd,e\  
fV~~J2IK  
public String getSFilePath() CGFDqCNr-  
{ #K&Gp-  
return sFilePath; +,l-Nz  
} 'fW-Y!k%  
4e  
y>LBl]  
public void setSFilePath(String value) 06jQE2z2R  
{ tX[WH\(xI  
sFilePath = value; bd`P0f?  
} F[MFx^sT{  
MfkZ  
SfR%s8c`  
public String getSFileName() _dU\JD  
{ Xc.`-J~Il  
return sFileName; #z42C?V  
} cb bFw  
4!$"ayGv;D  
zeRyL3fnmb  
public void setSFileName(String value) m+9#5a-  
{ 0`H# '/  
sFileName = value; qSQ~D(tO  
} 1*7@BP5  
Zd&S@Z  
('~LMu_  
public int getNSplitter() @nf`Gw ;  
{ |uDdHX8T  
return nSplitter; tp|d*7^i  
} $ Q0n  
31)&vf[[  
P2Y^d#jO  
public void setNSplitter(int nCount) Kpp_|2|@<  
{ Y*hCMy;  
nSplitter = nCount; h];I{crh  
} cCX*D_kCB  
} (sj,[  
[-&Zl(9&  
>dT*rH3w  
/* kVL.PY\K  
**Utility.java }WV:erg`  
*/ pk~WrqK}  
package NetFox; M=Wz  
)e{}V\;q  
QW"! (`K  
public class Utility { MQ4KdqgP  
$!DpjN  
%)wjR/o  
public Utility() \v/[6&|X0s  
{ Ss`LLq0LO  
^}r1;W?n  
T0 {Lq:  
} r*Xuj=  
;d?R:Uw8  
//线程睡眠 F[0]/  
public static void sleep(int nSecond) ~ K=b\xc^  
{ hOeRd#AQK  
try{ pJ{Y lS{  
Thread.sleep(nSecond); <vP=zk  
} ?# fQ~ s  
catch(Exception e) .^g p?  
{ gFh*eCo   
e.printStackTrace (); +h$ 9\  
} _-\#i  
} cZ06Kx..  
W8<%[-r  
//日志 ,vDbp?)'U  
public static void log(String sMsg) d'2A,B~_*  
{ liSmjsk  
System.err.println(sMsg); w>YDNOk  
} <uJ@:oWG7  
qWw=8Bq  
\DzGQ{`~m  
public static void log(int sMsg)  @8 6f  
{ 3sk9`=[{$  
System.err.println(sMsg); $J2Gf(RU  
} n*$ g]G$  
} Je{ykL?N  
:pUtSs7p}  
Yw9GN2AG  
/* ry!!9Z>9n  
**TestMethod.java W4N{S.#!  
*/ F5Va+z,jg  
package NetFox; j@9T.P1  
;);kEq/=P  
he4(hX^  
public class TestMethod { Y0>y8U V  
*2?@ |<(r  
&FD>&WRV  
public TestMethod() iB{V^ksU  
{ ///xx/weblogic60b2_win.exe fIF8%J ^3  
try{ 7 3m1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $^ P0F9~0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ZW}_DT0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); l ,8##7  
fileFetch.start(); MPV5P^@X  
} nR~(0G,H  
catch(Exception e){e.printStackTrace ();} nK,w]{<wG!  
hQ i2U  
}*-@!wc-N  
} 9iq_rd]  
o@Oqm>]SS  
nlYNN/@"  
public static void main(String[] args) OCUr{Nh  
{ kl`W\tF  
new TestMethod(); HhpDR  
} 68 sB )R  
} ;fJ.8C  
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