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http断点续传简单实现(java)

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/* 0$Zh4Y  
**SiteFileFetch.java =%>E8)Jb  
*/ @n9iOf~<  
package NetFox; MIZ!+[At  
import java.io.*; qX6zk0I a  
import java.net.*; ?;(!(<{  
n[v`F  
j\Fbi3H  
public class SiteFileFetch extends Thread { j E5=e</  
A]o3 MoSt  
%4#ChlXB  
SiteInfoBean siteInfoBean = null; //文件信息Bean #L*MMC"  
long[] nStartPos; //开始位置 {S%;By&[  
long[] nEndPos; //结束位置 L+lye Ir'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 U}=H1f,  
long nFileLength; //文件长度 *l0i}"T^_  
boolean bFirst = true; //是否第一次取文件 TC:t!:  
boolean bStop = false; //停止标志 (V/! 0Lj  
File tmpFile; //文件下载的临时信息 *_Pkb.3R  
DataOutputStream output; //输出到文件的输出流 NX]6RZr-  
w#bdb;  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) (~b0-3s  
public SiteFileFetch(SiteInfoBean bean) throws IOException A v/y  
{ 3A\Hiy!{F  
siteInfoBean = bean; #X5Tt  ;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WS@8Z0@RD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $uK[[k~=S  
if(tmpFile.exists ()) =_2(S6~  
{ L>57eF)7  
bFirst = false; + J}h  
read_nPos(); )$2h:dw_  
} 9!D c=  
else 2qKAO/_O  
{ C$v !emu  
nStartPos = new long[bean.getNSplitter()]; gaL.5_1  
nEndPos = new long[bean.getNSplitter()]; HNfd[#gV  
} ]}_Ohe]X  
S8]YS@@D   
`M_w^&6+n  
#Z_f/@b  
} <<1_rRL]  
-$D#u  
kAoh#8=  
public void run() @Z9>E+udQ  
{ ?T[K{t;~jo  
//获得文件长度 #)KQ-x,  
//分割文件 `{S4_'  
//实例FileSplitterFetch (i^<er q  
//启动FileSplitterFetch线程 TIP H#W:v  
//等待子线程返回 #~qY%X  
try{ byj7c(  
if(bFirst) o7:"Sl2AD  
{ L0xh?B  
nFileLength = getFileSize(); X,+N/ nku  
if(nFileLength == -1) -/6Ms%O  
{ {_J1m&/  
System.err.println("File Length is not known!"); Y2y = P  
} ew8Manx  
else if(nFileLength == -2) M0RVEhX  
{ v;R+{K87  
System.err.println("File is not access!"); 1f5;^T I  
} D4QL lP  
else YR68'Sft[  
{ 'Z^KpW  
for(int i=0;i<nStartPos.length;i++) jR,3 -JQ  
{ ",Fqpu&M  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |f"1I4K g  
} ~`Rooh3m  
for(int i=0;i<nEndPos.length-1;i++) Cv1CRmqq%  
{ 1`EkN0iZ  
nEndPos = nStartPos[i+1]; k|_LF[*Z  
} n'Z5rXg  
nEndPos[nEndPos.length-1] = nFileLength; )'t&LWS~  
} 'xc=N  
} )m$i``*<  
QU^?a~r  
Q!}LtR$  
//启动子线程 ln=:E$jX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ndB*^nT  
for(int i=0;i<nStartPos.length;i++) ]Saw}agE[%  
{ W q>qso  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1ba* U~OEg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ng<oz*>U  
nStartPos,nEndPos,i); u-#J!Z<T8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &+F}$8,  
fileSplitterFetch.start(); ^>!~%Vv7!  
} eWAgYe2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6I$:mHEhd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Eg|C  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7W\aX*]  
nEndPos = " + nFileLength); B"fKv0  
// fileSplitterFetch[nPos.length-1].start(); e.pq6D5  
\I`g[nT|  
!3Me 6&$O  
//等待子线程结束 UG<`m]  
//int count = 0; d7Devs k  
//是否结束while循环 c,RY j  
boolean breakWhile = false; SB2Ij',  
1:d,8  
5!^DKyw:  
while(!bStop) :~+m9r  
{ -axV;+"b  
write_nPos(); joJ:* oL  
Utility.sleep(500); rpO>l  
breakWhile = true; Z:s:NvFX  
H?<c eK'e  
0}y-DCuQ  
for(int i=0;i<nStartPos.length;i++) "jG-)k`a  
{ x$\w^h\F  
if(!fileSplitterFetch.bDownOver) '2.11cM3  
{ xKC{P{:  
breakWhile = false; ac??lHtH9  
break; 4Z<  
} 0vm}[a4+i;  
} G@;I^_gN  
if(breakWhile) uA2-&smw  
break; 4 Gm(P~N  
&SE+7HXw  
t.E3Fh!o  
//count++; o|0QstSCl  
//if(count>4) f.SmCgG  
// siteStop(); L=WB'*N  
} P",E/beV  
:Y;\1J<b1  
trC+Etc   
System.err.println("文件下载结束!"); CuD^@  
} PofHe  
catch(Exception e){e.printStackTrace ();} *X4$'LSx1  
} nmrYBw>  
&,B91H*#  
X}gnO83  
//获得文件长度 lm;G8IP`  
public long getFileSize() oPA [vY  
{ h*GU7<F:a  
int nFileLength = -1; T{%'"mm;  
try{ @)YQiE$  
URL url = new URL(siteInfoBean.getSSiteURL()); T>;Kq;(9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gwepaW  
httpConnection.setRequestProperty("User-Agent","NetFox"); d@72z r  
N%.Dj H  
(\6R"2  
int responseCode=httpConnection.getResponseCode(); zsx12b^w  
if(responseCode>=400) ?w[M{   
{ br9`77J8  
processErrorCode(responseCode); = 5 E:CP  
return -2; //-2 represent access is error yNb :zoT  
} dn1Tu6f;|  
nBVknyMFNF  
.{|AHW&0<  
String sHeader; FiQx5}MMhu  
<C'S#5,2  
F^]?'`7md  
for(int i=1;;i++) 6v9{ $:  
{ *ppb 4R;CW  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A<&:-Zz  
//Utility.log(in.readLine()); *0^t;A+  
sHeader=httpConnection.getHeaderFieldKey(i); d[9NNm*htC  
if(sHeader!=null) FDAREE\j  
{ jnoFNIW   
if(sHeader.equals("Content-Length")) B43o_H|s  
{ afZPju"-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); p ?HODwZ  
break; B`4[@$  
} A_t<SG5  
} S"=o U}'|  
else "iof -b=ys  
break; `f:5w^A  
} A*h)p@3t<  
} vR?L/G^.  
catch(IOException e){e.printStackTrace ();} Q#bFW?>y,  
catch(Exception e){e.printStackTrace ();} V#TA%>  
e;=G|E  
"z }bgy  
Utility.log(nFileLength); P-~Avb  
|yI?}zyR  
nDvny0^a  
return nFileLength; ;e0>.7m  
} 'FBvAk6  
^3`98y.Q  
(D8'qx-M  
//保存下载信息(文件指针位置) p;n)YY$  
private void write_nPos() jkNZv. )p  
{ Ze$:-7Czl  
try{ 'q[V*4g  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ji( S ?^  
output.writeInt(nStartPos.length); RWBmQg^]X  
for(int i=0;i<nStartPos.length;i++) r _r$nl  
{ JoZC+G  
// output.writeLong(nPos); (6\A"jey\x  
output.writeLong(fileSplitterFetch.nStartPos); ?NI)3-l  
output.writeLong(fileSplitterFetch.nEndPos); 4PUM.%  
} i=2+1 ;K  
output.close(); vS<;:3  
} RpLm'~N'  
catch(IOException e){e.printStackTrace ();} Ro:-u7q  
catch(Exception e){e.printStackTrace ();} v%aD:%wlY@  
} ]Ly)%a32  
4 qW)R{%  
dm$:xE":  
//读取保存的下载信息(文件指针位置) 72-@!Z0e  
private void read_nPos() 6}ax~wYct  
{ "E2 g7n&  
try{ `bC_J,>_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6-X7C9`C  
int nCount = input.readInt(); EoY#D'[  
nStartPos = new long[nCount]; 71/6=aq>n  
nEndPos = new long[nCount]; ?qK:P  
for(int i=0;i<nStartPos.length;i++) &2\.6rb.  
{ V,M8RYOnC!  
nStartPos = input.readLong(); M(3E b;`   
nEndPos = input.readLong(); GV[[[fu  
} U |4% ydG  
input.close(); hrAI@.Bo  
} 3 oWCQ  
catch(IOException e){e.printStackTrace ();} "J{,P9P6  
catch(Exception e){e.printStackTrace ();} 4t8 Hy  
} f CVSVn"o  
*smo{!0Gg  
P7Y[?='v  
private void processErrorCode(int nErrorCode) ng 6G<hi  
{ U&eLj"XZ  
System.err.println("Error Code : " + nErrorCode); krl yEAK=  
} oL6_Ya  
i'EXylb  
nEn2!)$  
//停止文件下载 Y|lMa?\E  
public void siteStop() vMI\$E &  
{ iCEX|Tj;  
bStop = true; '",5Bu#C  
for(int i=0;i<nStartPos.length;i++) _88~uYG  
fileSplitterFetch.splitterStop(); 7xd}J(l  
E|fPI u  
%Mu dc  
} jf2E{48P  
} {l1;&y?  
//负责部分文件的抓取 F% |(pHk  
**FileSplitterFetch.java JL$RBr  
*/ C eg6 o &^  
package NetFox; G dooy~cn  
@rdC/=Y[  
{oZ]1Qf_  
import java.io.*; =Vv{td  
import java.net.*; }$UFc1He\J  
l{3utQH-=z  
':[y]ep(~|  
public class FileSplitterFetch extends Thread { /[-hJ=< Yb  
>ylVES/V  
cP Y^Bf5)  
String sURL; //File URL AuCVpDH  
long nStartPos; //File Snippet Start Position =wQ=`  
long nEndPos; //File Snippet End Position 0'<S7?~|  
int nThreadID; //Thread's ID qnlj~]NV  
boolean bDownOver = false; //Downing is over 'F~u \m=E  
boolean bStop = false; //Stop identical Z~R i%XG  
FileAccessI fileAccessI = null; //File Access interface BKTsc/v2>:  
prWid3}  
E0|aI4S4  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Il642#Gh  
{ l(,;wAH  
this.sURL = sURL; 12sD|j  
this.nStartPos = nStart; tIb21c q  
this.nEndPos = nEnd; ^qO=~U!{  
nThreadID = id; @f{_=~+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ggI=I<7M  
} ^2^|AXNES  
,p!B"# ot  
/J.\p/%\  
public void run() =6L*!JP<  
{ <*"pra{3  
while(nStartPos < nEndPos && !bStop) 7grt4k  
{ LuP?$~z  
 (X(1kj3  
XDkS ^9  
try{ .L7Yf+yFg  
URL url = new URL(sURL); sQ}%7BMK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kz0I2!bt  
httpConnection.setRequestProperty("User-Agent","NetFox"); o)tKH@`vE  
String sProperty = "bytes="+nStartPos+"-"; l*K I  
httpConnection.setRequestProperty("RANGE",sProperty); f4'El2>-86  
Utility.log(sProperty); j?\$G.Y  
& =73D1A  
3cOY0Z#T  
InputStream input = httpConnection.getInputStream(); 5 [ ,+\  
//logResponseHead(httpConnection); VyecTU"W  
4D^ M<Xn  
By?nd)  
byte[] b = new byte[1024]; (;0$i?3\  
int nRead; ]By0Xifew  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /!=U +X  
{ J?UA:u  
nStartPos += fileAccessI.write(b,0,nRead); =oE_.ux\  
//if(nThreadID == 1) t_dcV%=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); & u$(NbK  
} UrO=!Gk  
N;-/wip  
LH=d[3Y  
Utility.log("Thread " + nThreadID + " is over!"); [ rQMD^:M$  
bDownOver = true; J>`v.8y  
//nPos = fileAccessI.write (b,0,nRead); 6xH;: B)d  
} [34zh="o  
catch(Exception e){e.printStackTrace ();} 7\IL  
} i[$-_  
} vO\:vp4fH  
GI4?|@%vD!  
8r,9OM  
//打印回应的头信息 bb|}'  
public void logResponseHead(HttpURLConnection con) Hx$.9'Oq\Q  
{ /"=29sWB  
for(int i=1;;i++) glv ;C/l  
{ (tepmcf  
String header=con.getHeaderFieldKey(i); 'KH lrmnr  
if(header!=null) 4~!Eje!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qQ^d9EK'?~  
Utility.log(header+" : "+con.getHeaderField(header)); & =G)NeT_  
else :-z&Y492  
break; _B)s=Snx  
} d$w(-tV42  
} Y?<)Dg.[  
vX ?aB!nkw  
w4UD/zO  
public void splitterStop() ".gNeY6)x  
{ ~p:?QB>1]  
bStop = true; oz LH]*  
} le.anJAr  
vd`O aM}#U  
80C(H!^  
} _6ZzuVv3/  
sm0fAL  
c&E]E(  
/* K4:  $=  
**FileAccess.java LT/mb2  
*//文件访问(定位,写) C0QM#"[  
package NetFox; gljo;f:  
import java.io.*; xYPxg!  
>%u@R3PH]  
\8{\;L C  
public class FileAccessI implements Serializable{ J/ vK6cO\  
eNbpwne  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4ZwKpQ6  
RandomAccessFile oSavedFile; ,!Q]q^{C:W  
long nPos; "oR@JbdX  
X3',vey  
7b,(\Fm  
public FileAccessI() throws IOException 3@_Elu  
{ E$A3|rjnoN  
this("",0); ;'0=T0\  
} eklgLU-+fW  
kJT+  
5!(?m~jJ  
public FileAccessI(String sName,long nPos) throws IOException 2}vNSQvG  
{ MLr-, "gs  
oSavedFile = new RandomAccessFile(sName,"rw"); '1Y\[T*  
this.nPos = nPos; @}&_Dvf  
oSavedFile.seek(nPos); vcv CD7MD  
} LHkQ'O0  
'#.#$8l  
) #+^ sAO  
public synchronized int write(byte[] b,int nStart,int nLen) YlF%UPp  
{ 2oCkG~j  
int n = -1; f0>!qt  
try{ NxA)@9Q  
oSavedFile.write(b,nStart,nLen); Qdf=XG5  
n = nLen; 3\:y8|  
} !.TLW  
catch(IOException e) }H"kU2l  
{ }4//@J?:  
e.printStackTrace (); AUe# RP  
} &(N+.T5cp  
sN6N >{  
{{yZ@>o6  
return n; D5,P)[  
} _iV]_\0W2  
`bjizS'^  
0#cy=*E  
} ,yd=e}lQx  
x[ 3A+  
nh>K`+>co  
/* ;j8 )KC  
**SiteInfoBean.java 3?n>yS  
*/ w= P 9FxB  
package NetFox; eKvV*[N a  
cLVeT  
:'iYxhM.V  
public class SiteInfoBean { =#gEB#$x:  
}Gyqq6Aeb  
s?R2B)a  
private String sSiteURL; //Site's URL u8GMUN  
private String sFilePath; //Saved File's Path kOo~%kcQ'  
private String sFileName; //Saved File's Name %zk$}}ti.  
private int nSplitter; //Count of Splited Downloading File Y!J>U  
7R!5,Js+  
??60,m:]  
public SiteInfoBean() NKb1LbnZ*y  
{//nSplitter的缺省值为5 \*f;Xaa  
//default value of nSplitter is 5 e [_m< e  
this("","","",5); qMt++*Ls  
} zOgTQs"ZH  
03E4cYxt5  
4k-+?L!/G  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *jIqAhs0{  
{ mE%$HZ}  
sSiteURL= sURL; _j?e~w&0b  
sFilePath = sPath; _WXtB#  
sFileName = sName; u VyGk~  
this.nSplitter = nSpiltter; 2owEw*5jl/  
o]:3H8  
Ig]iT  
} kVK/9dy-F  
OCZaQ33  
Suk  
public String getSSiteURL() Sf5X3,Uw  
{ $Iv2j">3)  
return sSiteURL; W"^wnGa@a  
} c:Wze*vI ;  
om?-WJI  
|sRipWh  
public void setSSiteURL(String value) Mi'8 ~J  
{ 26T"XW'_  
sSiteURL = value; ] e. JNo  
} <\kr1qH H  
iu&wO<)+?  
l2N]a9bq@  
public String getSFilePath() iY"l}.7)  
{ 9z)5Mdf1j  
return sFilePath; w?kJ+lmOQy  
} dT,o=8fg  
"BX!  
E dZ\1'&/9  
public void setSFilePath(String value) gUyR_5q)8l  
{ T^J>ZDA  
sFilePath = value; 0d8%T<=J  
} GFr|E8  
u#}[ZoI  
x#Sqn#  
public String getSFileName() F 8B#}%JE  
{ ( Jz;W<E  
return sFileName; pPd#N'\*  
} 9]q:[zm^  
&gzCteS  
#>Zzf  
public void setSFileName(String value) ;2B{9{  
{ @E:,lA  
sFileName = value; ?-^~f  
} OS8q( 2z?s  
(?nCy HC%g  
6k#Jpmmr  
public int getNSplitter() !%$`Eq)M^7  
{ qucq,Yw  
return nSplitter; x c{hC4^V  
} x?&$ci  
,}K<*t[I  
[jmd  
public void setNSplitter(int nCount) !.d@L6  
{ 9k{PBAP  
nSplitter = nCount; %2v4<icvq  
} L|p Z$HB  
} h: 9Zt0,  
#8)*1?  
;Iq/l%vX  
/* l+V>]?j  
**Utility.java ~6p[El#tS  
*/ CHz+814  
package NetFox; ocs+d\  
e=.]F*:J  
ght$9>'n  
public class Utility { T?X_c"{8M  
R=jI?p  
x&0vKo;  
public Utility() S\;V4@<Kn  
{ M3q|l7|9  
x)@G;nZ  
Hro-d 1J7  
} 6fw(T.Pe  
>3Eo@J,?d  
//线程睡眠 I"GB <oB  
public static void sleep(int nSecond) 9g<7i  
{ =zz ~kon9  
try{ t2)rUWg  
Thread.sleep(nSecond); 5k.oW=  
} ~;N^g4s  
catch(Exception e) >Z5gSs0  
{ :\|SQKD  
e.printStackTrace (); 9E6_]8rl  
} `E>1>'  
} Ig f&l`\  
>G%o,9i  
//日志 dUhY\v oQ  
public static void log(String sMsg) ajEjZ6  
{ @<elq'2  
System.err.println(sMsg); `7r@a  
} maNl^i  
3eF -8Z(f  
sc}~8T  
public static void log(int sMsg) Sn|BlXrey  
{ I"A_b}~*}  
System.err.println(sMsg); GaK-t*Q  
} e7sp =I ,  
} <P=twT;P  
qHrc9fB  
+8RgF   
/* Kkm>e{0)AY  
**TestMethod.java ++^l]8  
*/ B&n<M]7  
package NetFox; ]jo1{IcI  
^y<<>Y'I  
xjKR R?  
public class TestMethod { G U( _  
;;#qmGoE  
)% ~OH  
public TestMethod() a m|F?|1  
{ ///xx/weblogic60b2_win.exe 73/P&hT  
try{ *Qg_F6y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,)vDeU  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); K/|Z$4S  
SiteFileFetch fileFetch = new SiteFileFetch(bean); x$6^R q>2  
fileFetch.start(); vzim<;i  
} E2Q[ZoVS  
catch(Exception e){e.printStackTrace ();} {?:X8&Sf  
Hl{S]]z  
iT2B'QI=<  
}  J4f i'  
e,W%uH>X  
NTYg[VTr  
public static void main(String[] args) %H]ptH5  
{ ur:3W6ZKl  
new TestMethod(); hhCrUn"  
} VHIOwzC  
} 0Ziw_S\d&s  
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