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http断点续传简单实现(java)

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/* v=k+MvX  
**SiteFileFetch.java .j4y0dh33  
*/ Ed=/w6<  
package NetFox; a%%7Ew ?  
import java.io.*; tA(oD4H9  
import java.net.*; '\bokwsP  
E@ea ?Sx  
)1At/mr  
public class SiteFileFetch extends Thread { S{^x]h|?  
13?:a[~=Y  
j4XVk@'OX  
SiteInfoBean siteInfoBean = null; //文件信息Bean 8m0*89HEu  
long[] nStartPos; //开始位置 f ,e]jw@  
long[] nEndPos; //结束位置 =M1}HF,7>l  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 vu( 5s  
long nFileLength; //文件长度 ?mNB:-Q  
boolean bFirst = true; //是否第一次取文件 ^q-%#  
boolean bStop = false; //停止标志 OY1bFIE  
File tmpFile; //文件下载的临时信息 & AK\Pw)  
DataOutputStream output; //输出到文件的输出流 I~l qg  
{V7mpVTX.  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `l45T~`]$  
public SiteFileFetch(SiteInfoBean bean) throws IOException `+w= p7ET  
{ )>~ jjR  
siteInfoBean = bean; k| OM?\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "L.k m  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Zj[m  
if(tmpFile.exists ()) Sh#N5kgD  
{ ;Z*rY?v  
bFirst = false; W3~u J(  
read_nPos(); n n F  
} q 4Pv\YO  
else _i>_Sn1"  
{ (Z<@dkO?)  
nStartPos = new long[bean.getNSplitter()]; B  W*8  
nEndPos = new long[bean.getNSplitter()]; g;Ugr8  
} 18X?CoM~  
"E+;O,N-  
Ucv7`W gr  
*Xnf}Ozx  
} qt9jZtx  
+E. D:  
|ru!C(  
public void run() e!J5h <:  
{  8s22VL  
//获得文件长度 4- QlIIf  
//分割文件 6r"NU`1A;r  
//实例FileSplitterFetch _1)n_P4  
//启动FileSplitterFetch线程 kb 74:  
//等待子线程返回 A$p&<#  
try{ <yl@!-'J7  
if(bFirst) 6n/=n%US  
{ 8b0j rt  
nFileLength = getFileSize(); od#Lad@p  
if(nFileLength == -1) Foq3==*p  
{ ], Bafz)4  
System.err.println("File Length is not known!"); Pfs_tu  
} uKzx >\}?1  
else if(nFileLength == -2) B^9C}QB  
{ ajkV"~w',|  
System.err.println("File is not access!"); +6>2= ,?Z  
} xJ<RQCW$  
else Pz*BuL <  
{ 1q;R+65  
for(int i=0;i<nStartPos.length;i++) W/A@qo"  
{ YKUAI+ks  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @|;[ ;:h@  
} 0Gj/yra9MO  
for(int i=0;i<nEndPos.length-1;i++) ;Qy Ew5  
{ ,X|FyO(p  
nEndPos = nStartPos[i+1]; lI46 f  
} \>4>sCC  
nEndPos[nEndPos.length-1] = nFileLength; I!Dx)>E&  
} !^Ay !  
} -J!n7  
aNM*=y`  
!0^4D=dO  
//启动子线程 zEQQ4)mA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [ -Z 6QzT  
for(int i=0;i<nStartPos.length;i++) ~i?Jg/qcxN  
{ {R(/Usg!=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8yYag[m8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }JOz,SQHP  
nStartPos,nEndPos,i); T-n>+G{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >r)UDa+  
fileSplitterFetch.start(); rc:UG "[  
} .z$UNB(!M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9FC_B+7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M`#g>~bI#R  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g<~ODMCO?W  
nEndPos = " + nFileLength); sMAH;'`!Eu  
// fileSplitterFetch[nPos.length-1].start(); \3(s&K\Y6\  
{|%^'lS  
zZ9Ei-Q  
//等待子线程结束 i`6utOq  
//int count = 0; G@e;ms1  
//是否结束while循环 ve a$G~[%6  
boolean breakWhile = false; =|O]X|y-lZ  
[$$R>ELYQ  
;=%cA#}_0  
while(!bStop) IN;!s#cl:  
{ MC-Z6l2  
write_nPos(); uFuH/(}K[  
Utility.sleep(500); U3aM^  
breakWhile = true; ^eoW+OxH  
\4G9 fR4  
# mM9^LJ   
for(int i=0;i<nStartPos.length;i++) "a _S7K  
{ (.z0.0W  
if(!fileSplitterFetch.bDownOver) (0_]=r=q  
{ pi;fu  
breakWhile = false; bQ?Vh@j(M  
break; <vs*aFq  
} [$>@f{:  
} $+{o*  
if(breakWhile) BD.l5 ~:  
break; ~y 2joStx  
.ezko\nU  
HWL? doM  
//count++; Q[!?SSX%  
//if(count>4) D!)h92CIDm  
// siteStop(); KLj/,ehD !  
} I?q- :9:  
!t)uRJ   
h^."wv  
System.err.println("文件下载结束!"); +5GC?cW  
} djdSD  
catch(Exception e){e.printStackTrace ();} (:+Wc^0  
} H?=[9?1wI5  
Vn^8nS  
Nhjz~S<o  
//获得文件长度 bL:+(/:  
public long getFileSize() je:J`4k$  
{ vXSpn71Jb  
int nFileLength = -1; d| {<SRAI  
try{ vMXn#eR  
URL url = new URL(siteInfoBean.getSSiteURL()); >G0ihhVt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); MzW!iG  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;$r!eFY;  
Pl|*+g  
hz2f7g  
int responseCode=httpConnection.getResponseCode(); WK SWOSJ  
if(responseCode>=400) p|r>tBv?x  
{ 5B{Eg?  
processErrorCode(responseCode); +jGUp\h%9;  
return -2; //-2 represent access is error 1 x0)mt3  
} 'Te'wh=Y  
eYg0 NEq{  
0M}Ql5+h,  
String sHeader; NA$ODK -  
lb)i0`AN+  
${U H!n{  
for(int i=1;;i++) QSo48OFs  
{ K!G/iz9SB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); BQ~\p\  
//Utility.log(in.readLine()); K+U0YMRmz  
sHeader=httpConnection.getHeaderFieldKey(i); i+Xb3+R  
if(sHeader!=null) *^%ohCU i  
{ AIwp2Fz  
if(sHeader.equals("Content-Length")) < $rXQ  
{ `b5pa`\4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ; JHf0  
break; 4=;`\-7!  
} #fF';Y7  
} h`:gMhn  
else wo) lkovd  
break; _4t  
} n6GB2<y  
} 4V5h1/JPm  
catch(IOException e){e.printStackTrace ();} eOd'i{f@F  
catch(Exception e){e.printStackTrace ();} y-:d`>b>\  
OmECvL'Z  
[Kanj/  
Utility.log(nFileLength); TP)}1 @  
#Bas+8 @,  
4{=^J2z  
return nFileLength; I6 Q{ Axy  
} pU@ &-  
Ivc/g,  
~jOk?^6  
//保存下载信息(文件指针位置) y$HV;%G{26  
private void write_nPos() +zsB~Vz  
{ ,S=ur%  
try{ s ` +cQ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); CF@j]I@{   
output.writeInt(nStartPos.length); 5+iXOs<   
for(int i=0;i<nStartPos.length;i++) H_7EK  
{ 32,Y 3!%  
// output.writeLong(nPos); 0\yA6`}!  
output.writeLong(fileSplitterFetch.nStartPos); XXPpj< c  
output.writeLong(fileSplitterFetch.nEndPos); R}cNhZC  
} R7U%v"F>`  
output.close(); ]Vmo >  
} TQmrL  
catch(IOException e){e.printStackTrace ();} d^J)Mhju  
catch(Exception e){e.printStackTrace ();} -U\'Emu4  
} #]6{>n1*+w  
T=)qD2?  
E3l*_b0  
//读取保存的下载信息(文件指针位置) 1. +6x4%rV  
private void read_nPos() 1]eRragm"  
{ ;-XfbqZ\  
try{ wMj #.Jh  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); CGzu(@dd\  
int nCount = input.readInt(); "TJ*mN.i{}  
nStartPos = new long[nCount]; atF#0*e>  
nEndPos = new long[nCount]; B~7!v${  
for(int i=0;i<nStartPos.length;i++) g&y^r/  
{ dzBP<Xyh  
nStartPos = input.readLong(); huS*1xl  
nEndPos = input.readLong(); b0YEIV<$  
} W>i"p~!  
input.close(); (S?Y3l|  
} g_`a_0v  
catch(IOException e){e.printStackTrace ();} ($kw*H{Ah^  
catch(Exception e){e.printStackTrace ();} *<!q@r<d  
} )0iN2L]U;  
*; ]}`r  
_1&Ar4:  
private void processErrorCode(int nErrorCode) ~bx ev/$d  
{ (nt`8 0  
System.err.println("Error Code : " + nErrorCode); 4$[o;t>  
} n\l?+)S *  
gWGDm~+  
No} U[u.O  
//停止文件下载 z&tC5]#  
public void siteStop() w|-3X  
{ (X,i,qK/  
bStop = true; jt on\9  
for(int i=0;i<nStartPos.length;i++) w+R7NFq  
fileSplitterFetch.splitterStop(); r O$pj~!|Q  
(pd$?vRy  
LCH\;07V#  
} H{vKk  
} ,M;9|kE*  
//负责部分文件的抓取 L|T?,^  
**FileSplitterFetch.java e))L&s  
*/ 32<D9_  
package NetFox; jRg gj`o  
@%R4V[Lo.  
@m9pb+=v  
import java.io.*; 2CO/K_Q  
import java.net.*; Z|uvrFa  
MhD'  
)*;Tt @'y  
public class FileSplitterFetch extends Thread { &,k!,<IF  
j#n ]q{s4  
5]N0p,f  
String sURL; //File URL ORs :S$Nt$  
long nStartPos; //File Snippet Start Position d#rr7O  
long nEndPos; //File Snippet End Position !H\o Qv-I  
int nThreadID; //Thread's ID <|}Z6Ti  
boolean bDownOver = false; //Downing is over qY#*LqV  
boolean bStop = false; //Stop identical T+}|$/Tv  
FileAccessI fileAccessI = null; //File Access interface j2MA['{  
9j>2C  
-[7+g  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #cfiN b}GX  
{ 4d@yAr}  
this.sURL = sURL; #c^]p/  
this.nStartPos = nStart; rUb{iU;~m  
this.nEndPos = nEnd; 1'E=R0`pA  
nThreadID = id; E(r_mF7:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _YF>Y=D-  
} sm/a L^4  
bkV<ZUW|;  
 !Ld5Y$  
public void run() xSmG,}3mF  
{ 2<EV iP9  
while(nStartPos < nEndPos && !bStop) o72r `2  
{ h+Co:pr  
(u@:PiU/eP  
XjGS.&'I  
try{ +; KUL6  
URL url = new URL(sURL); &j F'2D^_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  ##rkyd  
httpConnection.setRequestProperty("User-Agent","NetFox"); *4U_MM#rX  
String sProperty = "bytes="+nStartPos+"-"; =0g!Q   
httpConnection.setRequestProperty("RANGE",sProperty); Fc1!i8vv  
Utility.log(sProperty); 4E^ ?}_$  
m)tu~ neM  
0~qc,-)3  
InputStream input = httpConnection.getInputStream(); S0^a)#D &  
//logResponseHead(httpConnection); #DUfEZ  
f*o  
&>JP.//spi  
byte[] b = new byte[1024]; QRQZ{m  
int nRead; 6'Q{xJe?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7?Wte&C];p  
{ SOOVUMj  
nStartPos += fileAccessI.write(b,0,nRead); qIi \[Ugh  
//if(nThreadID == 1) HOP*QX8C%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T8o](:B~  
} "2cOSPpQL  
:wC\IwG~CE  
7iP+!e}$.  
Utility.log("Thread " + nThreadID + " is over!"); uHgq"e  
bDownOver = true; ~1uQyt  
//nPos = fileAccessI.write (b,0,nRead); M=^d  
} ZxF`i>/h  
catch(Exception e){e.printStackTrace ();} eY<<Hld  
} \Bo%2O%4  
} 6'#5Dqw"r  
;st0Ekni)  
N:lfKI  
//打印回应的头信息 C"I jr=w  
public void logResponseHead(HttpURLConnection con) E4 X6f  
{ uM2@&)u  
for(int i=1;;i++) N'`X:7fN  
{ xKUL}>8  
String header=con.getHeaderFieldKey(i); W"NI^OX  
if(header!=null) [^qT?se{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >d + }$dB  
Utility.log(header+" : "+con.getHeaderField(header)); Nfa&r  
else M"3"6U/e  
break; _**Nlp*%  
} j, 0`k  
} 'UlVc2%{  
d[a(u WEl  
KQ\K :#  
public void splitterStop()  /qLO/Mim  
{ #V>R#Oh}  
bStop = true; T\l`Y-vu  
} _;HdX$op  
*9'3 `^l  
0S{23L4C  
} Hyb(.hlZh  
@DysM~I  
 *&_*G~>D  
/* tsb[=W!Ar8  
**FileAccess.java PT/Nz+  
*//文件访问(定位,写) $+4DpqJ  
package NetFox; kdNo<x1o  
import java.io.*; Y1PR?c Q  
&L8RLSfX  
\=%lH= yS  
public class FileAccessI implements Serializable{ s)-oCT$[  
9?l a5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 5JzvT JMx  
RandomAccessFile oSavedFile; VF?H0}YSHb  
long nPos; KF rsXf  
sfXFh  
f}-'67*Y  
public FileAccessI() throws IOException J^7m?mA  
{ {$frR "K  
this("",0); {)" 3  
} KIF9[/P  
wps/{h,  
u&zY>'}zm  
public FileAccessI(String sName,long nPos) throws IOException alb3oipOB  
{ khy'Y&\F;  
oSavedFile = new RandomAccessFile(sName,"rw"); a#p+.)Wm  
this.nPos = nPos; Rta}*  
oSavedFile.seek(nPos); o#qdgZ  
} Sz0PZtJ  
-@N-i$!;J  
rL5=8l  
public synchronized int write(byte[] b,int nStart,int nLen) _}R$h=YD  
{ R~g|w4a@sC  
int n = -1; ^+(5[z  
try{ "tyRnUP  
oSavedFile.write(b,nStart,nLen); h#0n2o#  
n = nLen; i%i~qTN  
} yY$^ R|t  
catch(IOException e) ifn=De3+  
{ LW1 4 'A}  
e.printStackTrace (); H oQb.Z  
} FvsVfV U  
k3Yu"GY^  
#BRIp(65-6  
return n; N#u'SGTG  
} u&~Xgq5[  
<'=!f6Wh  
f`qy~M&  
} NO5k1/-  
~n 'A1  
+`>7cy%cZ  
/* t'_EcYNS  
**SiteInfoBean.java  2s}S9  
*/ kff N0(MR  
package NetFox; ILuQ.VhBVN  
Fyvo;1a  
!8 @yi"n  
public class SiteInfoBean { uEgR>X>  
yi8vD~aA[  
H; `F}qQ3  
private String sSiteURL; //Site's URL gJ l^K  
private String sFilePath; //Saved File's Path INnd TF  
private String sFileName; //Saved File's Name 19fa7E<  
private int nSplitter; //Count of Splited Downloading File [Qs`@u<%  
=z}PR1X!  
;0eVE  
public SiteInfoBean() 5AT^puL]]  
{//nSplitter的缺省值为5 a 4?A 5  
//default value of nSplitter is 5 qT?{}I  
this("","","",5); !Yc:yF  
} (aYu[ML  
9d1km~  
..yV=idI  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :'DX M{  
{ %; &lVIU0  
sSiteURL= sURL; E$%v);u  
sFilePath = sPath;  ]]p\1G  
sFileName = sName; 3nA^s"#p  
this.nSplitter = nSpiltter; 59nRk}^$se  
DT-.Gdb8  
Q7x[08TI  
} ";.j[p:gi  
"'5(UiSFz  
%Za}q]?  
public String getSSiteURL() ?q6#M&|j/I  
{ w,P@@Q E  
return sSiteURL; i?^L",[  
} mX|M]^_,z  
&wi+)d  
xn, u$@F  
public void setSSiteURL(String value) {)Wf[2zJ  
{ RrxbsG1HP  
sSiteURL = value; -+F,L8  
} ET^?>YsA  
POk5+^  
6EC',=)6R  
public String getSFilePath() {5VJprTbv  
{ :G6CWE  
return sFilePath; RV]#Bg*[#  
} @Yt394gA%\  
}S iR;2W  
oY~q^Y  
public void setSFilePath(String value) hV $Zr4'  
{ ta95]|z"j  
sFilePath = value; ,~7~ S"  
} g]j&F65D  
6}Y==GP t  
8$c) ]Bv  
public String getSFileName() wMkHx3XD  
{ ]ovtH .y  
return sFileName; RQ0^ 1 R  
} kmW/{I9,ua  
b7hICO-w  
PM!JjMeQh  
public void setSFileName(String value) 2aTq?ZR|8A  
{ (6/aHSXI  
sFileName = value; F u5zj\0J  
} S? Cd,WxT  
*_YH}U  
<:AA R2=  
public int getNSplitter() h}|.#!C3  
{ <c5g-*V:  
return nSplitter; kJ%a;p`O  
} G5|nt#>  
!pj&h0CR  
3\ ]j4*i!  
public void setNSplitter(int nCount) |;:Kn*0/]  
{ cY+fZ=  
nSplitter = nCount; kXdXyq  
} pFs/ipZX^*  
} W $mw9  
gcI<bY  
VI|2vV6?  
/* tSni[,4Kq  
**Utility.java [g`4$_9S  
*/ ^7Z? }tgU  
package NetFox; 16N |  
6Ik v}q_j  
daCkjDGl\  
public class Utility { Hi2JG{i  
_s<BXj  
KXz7l\1Gb  
public Utility() t%,:L.?J#  
{ yD$d^/:  
N,8.W"fV  
3xRn  
} |F\fdB}?S:  
#zgO_ H  
//线程睡眠 )b%zYD9p  
public static void sleep(int nSecond) 00SS<iX  
{ J!|R1  
try{ w`< {   
Thread.sleep(nSecond); 9Y:.v@:}0  
} F( /Ka@  
catch(Exception e) ~-G_c=E?  
{ zgGJ<=G.  
e.printStackTrace (); }4piZ ch  
} pKLNBR|  
} `|&0j4(Pg  
? 47"$=G  
//日志 NBBR>3nt  
public static void log(String sMsg) 'ahZ*@kr  
{ fGA#0/_`  
System.err.println(sMsg); <e S+3,  
} j%ZBAk)}  
Z<=L  
\|B\7a'4  
public static void log(int sMsg) {~#PM>f  
{ p Djt\R<f  
System.err.println(sMsg); 4$mtc*tzT  
} wSM(!:on5  
} Wwr  
zmu+un"\j  
y,OG9iD:h  
/* ;;C2t&(  
**TestMethod.java xDPR^xY  
*/ WlW%z(RC  
package NetFox; 0N]\f.=`  
b>#=7;  
7hLh}  
public class TestMethod { .!+7|us8l\  
sk:B; .z  
Brd9"M|d  
public TestMethod() py%~Qz%  
{ ///xx/weblogic60b2_win.exe r XBC M  
try{ /C <p^#g9.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); x TH3g^E  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); i6P$>8jBQ-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); mQSn*;9\T3  
fileFetch.start(); W|E %  
} a2]ZYY`R7  
catch(Exception e){e.printStackTrace ();} A>mk0P)~Q  
E.0J94>iM  
Jk7 Am-.0  
} yc`3)  
p&4n"hC  
C9""sVs  
public static void main(String[] args) *XYp~b  
{ 6v3l^~kc'  
new TestMethod(); F;ttqL  
} RBrb7D{  
} =Q(J!f  
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