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http断点续传简单实现(java)

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/* Zdv.PGn  
**SiteFileFetch.java 9">zdFC'  
*/ ioB|*D<U2  
package NetFox; q[{:  
import java.io.*; d&}pgb-Md  
import java.net.*; =y)p>3p}&  
F^ I\X  
$q Zc!Qc  
public class SiteFileFetch extends Thread { ^=eq .(>  
LYd}w(}  
xN#bzma  
SiteInfoBean siteInfoBean = null; //文件信息Bean vOos*&  
long[] nStartPos; //开始位置 RL?u n}Qa  
long[] nEndPos; //结束位置 G{@C"H[$<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ni+3b  
long nFileLength; //文件长度 I#"t'=9H  
boolean bFirst = true; //是否第一次取文件 zq,iLoY[R  
boolean bStop = false; //停止标志 >Y7r \  
File tmpFile; //文件下载的临时信息 H7{Q@D8  
DataOutputStream output; //输出到文件的输出流 cU7rq j_  
^y:FjQC:  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) T?W[Z_D  
public SiteFileFetch(SiteInfoBean bean) throws IOException nqZA|-}  
{ W3^zIj  
siteInfoBean = bean; `d75@0:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); c5X`_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q:vz?G  
if(tmpFile.exists ()) 1*Sr5N[=  
{ . _1jk  
bFirst = false; g d z  
read_nPos(); .CVUEK@Z4  
} k1wCa^*gc  
else "e~k-\^Y  
{ S3SV.C:z>  
nStartPos = new long[bean.getNSplitter()]; 'I&|1I^  
nEndPos = new long[bean.getNSplitter()]; ,`;jvY~Ec  
} RS'} nY}  
HR;/Br  
uA~YRKer  
y)6,0K {k  
} "kX`FaAhY  
G7 1U7  
sa_R$ /H  
public void run() u FMIY(vB  
{ DC&A1I&  
//获得文件长度 /@Ez" ?V2  
//分割文件 C1V# ?03eI  
//实例FileSplitterFetch !tI=`Ml[  
//启动FileSplitterFetch线程 3DH.4@7P  
//等待子线程返回 pss6Oz8  
try{ _)Qy4[S=d  
if(bFirst) , Hn7(^t  
{ BEln6zj  
nFileLength = getFileSize(); bFSlf5*H  
if(nFileLength == -1) pFpZbU^  
{ (Up'$J}  
System.err.println("File Length is not known!"); L{=l#vu  
} N;<//,  
else if(nFileLength == -2) <D;MT96SG  
{ "LOnDa7E^  
System.err.println("File is not access!"); [#0Yt/G  
} cFLd)mt/  
else 4GVNw!V  
{ T'8RkDI}-  
for(int i=0;i<nStartPos.length;i++) YZibi  
{ X6xx2v%D  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); DR6]-j!FK  
} qh-[L  
for(int i=0;i<nEndPos.length-1;i++) Qu`n&  
{ tVunh3-  
nEndPos = nStartPos[i+1]; :y\09)CJK  
} ,*dzJT$k  
nEndPos[nEndPos.length-1] = nFileLength; X:Q$gO?[4  
} gA_krK ,Z  
} r=qLaPG  
yIOLs}!SF  
qbXz7s*{  
//启动子线程 9mQ#L<Ps  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; v Xb:  
for(int i=0;i<nStartPos.length;i++) $_)=8"Sn  
{ z5 Bi=~=#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @F?=a*s"!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gv9=quG  
nStartPos,nEndPos,i); a"QU:<-v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =O,JAR"ug  
fileSplitterFetch.start(); R*yU<9Mm8  
} MHo1 lrZa+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [h4o7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); k5@d! }#c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8a9RML}G<  
nEndPos = " + nFileLength); =<{ RX8  
// fileSplitterFetch[nPos.length-1].start(); %w7m\nw@  
ZW*n /#GUC  
JvkL37^ n:  
//等待子线程结束 u?kD)5Nk  
//int count = 0; !qA8Zky_  
//是否结束while循环 a=+T95ulDy  
boolean breakWhile = false; khAqYu" )  
NhA#bn9y?  
v)):$s?WB  
while(!bStop) Wt J{  
{ &EovZ@u  
write_nPos(); Fd7*]a  
Utility.sleep(500); G AQ 'Ti1!  
breakWhile = true; H?uukmZl  
9= V>f )R  
^mg*;8e Ga  
for(int i=0;i<nStartPos.length;i++) [T`}yb@  
{ 3sFeP &  
if(!fileSplitterFetch.bDownOver) 8Mu;U3cIW  
{ se!mb _!  
breakWhile = false; Q.k :\m*h  
break; /s c.C  
}  ]>Si0%  
} M^6$ MMx  
if(breakWhile) W&(f&{A  
break; Ax!Gu$K2o  
kZVm1W1  
iq6a|XGi  
//count++; 6z?gg3GV  
//if(count>4) ~O: U|&  
// siteStop(); |)o#|Qo  
} EvE,Dm?h  
W J+> e+  
SMoz:J*Q(  
System.err.println("文件下载结束!"); f-g1[!"F  
} 6GYtY>  
catch(Exception e){e.printStackTrace ();} ([ dT!B#aH  
} EfiU$ 8y  
\ZD[ !w7  
`HW:^T  
//获得文件长度 \Hwg) Uc{  
public long getFileSize() F98i*K`"  
{ ?t rV72D  
int nFileLength = -1; `.=sTp2rbc  
try{ Z0ReWrl;`  
URL url = new URL(siteInfoBean.getSSiteURL()); ~ y;y(4<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jxw_*^w"  
httpConnection.setRequestProperty("User-Agent","NetFox"); R8&|+ya  
:eOR-}p'  
nrpI5t.b  
int responseCode=httpConnection.getResponseCode(); 8g*hvPc  
if(responseCode>=400) *7" L]6  
{ 4_LQ?U>$  
processErrorCode(responseCode); :?CQuEv-  
return -2; //-2 represent access is error Y ?'tUV  
} 9<s4yZF@x  
~]WVG@-  
,P6=~q3k  
String sHeader; aMK~1]Cx  
V5"HwN+`  
dqe7sZl!  
for(int i=1;;i++) O8|*M "  
{ b |7ja_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1;&;5  
//Utility.log(in.readLine()); =Q(vni83<  
sHeader=httpConnection.getHeaderFieldKey(i); DjHp+TyT  
if(sHeader!=null) 4v dNMV~  
{ 'iUg[{'+  
if(sHeader.equals("Content-Length")) &uM^0eM  
{ GXX+}=b7qO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (~s|=Hxq|-  
break; f9TV%fG?  
} & ,L9OU  
} 8o-bd_  
else 2~c~{ jl\  
break; ?Zz'|.l@  
} 9z ?7{2C  
} K:5eek  
catch(IOException e){e.printStackTrace ();} u&]vd /  
catch(Exception e){e.printStackTrace ();} N[U9d}Zv  
>dQK.CG  
8#LJ*o  
Utility.log(nFileLength); x#8w6@iPQ  
J]pa4C`  
eThy+  
return nFileLength; ULBg {e?l8  
} UQT'6* !  
.q;ED`G  
mBk5+KyT  
//保存下载信息(文件指针位置) ijUzC>O+q  
private void write_nPos() +MUwP(U=w  
{ xxa} YIe8  
try{ qpqokK  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -5>NE35Cto  
output.writeInt(nStartPos.length); =%qEf   
for(int i=0;i<nStartPos.length;i++) F#V q#|_)>  
{ p-$Cs _{Z  
// output.writeLong(nPos); \ijMw  
output.writeLong(fileSplitterFetch.nStartPos); u oVNK  
output.writeLong(fileSplitterFetch.nEndPos); Qv#]81i(1  
} d^V$Z6* ]  
output.close(); E9 Y\X  
} 9=+-QdX+0]  
catch(IOException e){e.printStackTrace ();} S>_27r{  
catch(Exception e){e.printStackTrace ();} :q+N&j'3  
} I mym+  
R+=a`0_S  
#y; yN7W  
//读取保存的下载信息(文件指针位置) BW Uq%o,@g  
private void read_nPos() &ITuyGmF  
{ vRhnX  
try{ Hs?zq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F^kwdS  
int nCount = input.readInt(); &%F@O<:  
nStartPos = new long[nCount]; 30F!kP*E  
nEndPos = new long[nCount]; Y=B3q8l5  
for(int i=0;i<nStartPos.length;i++) fA^Em)cs2  
{ "="O >  
nStartPos = input.readLong(); n:#TOU1ix<  
nEndPos = input.readLong(); F0dI/+  
} 3$p#;a:=n  
input.close(); Utt>H@t[  
} i~yX tya  
catch(IOException e){e.printStackTrace ();} (#Mp 5C'X  
catch(Exception e){e.printStackTrace ();} }e{qW  
} ]/dVRkZeAE  
TKI$hc3|L  
D`o<,Y  
private void processErrorCode(int nErrorCode) d?L\pN&  
{ .BZVX=x  
System.err.println("Error Code : " + nErrorCode); FGanxv@15  
} =Hu0v}i/  
TI9X.E?  
#hxyOq,  
//停止文件下载 & 0v.E"0<  
public void siteStop()  46,j9x  
{ $k 2)8#\  
bStop = true; Nhf~PO({&  
for(int i=0;i<nStartPos.length;i++) dcq#TBo8  
fileSplitterFetch.splitterStop(); Q~,YbZ-7  
hR)2xz  
--k:a$Nt  
} `T WN^0!]  
} Dy9\O77>  
//负责部分文件的抓取 <8o(CA\  
**FileSplitterFetch.java @LX6hm*}  
*/ M]EsS^/X  
package NetFox; )pgrl  
`y!/F?o+!  
>-cfZ9{!  
import java.io.*; &a)vdlZSE=  
import java.net.*; TT}]wZ  
p2pAvlNoF  
JWHS nu!  
public class FileSplitterFetch extends Thread { r|R7- HI  
:BZ0 7`9  
c{3rl;Cs  
String sURL; //File URL s: |M].  
long nStartPos; //File Snippet Start Position JdNF-64ky  
long nEndPos; //File Snippet End Position bI ITPxz  
int nThreadID; //Thread's ID SN">gmY+  
boolean bDownOver = false; //Downing is over vA&Vu"}S  
boolean bStop = false; //Stop identical ;5S}~+j  
FileAccessI fileAccessI = null; //File Access interface \C|cp|A*&  
4E3g,%9u  
ecHP &Z$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Wk7WK` >i  
{ %FA@)?~  
this.sURL = sURL; t9 F=^)s  
this.nStartPos = nStart; BGWAh2w6  
this.nEndPos = nEnd; <[Oo*:A!7  
nThreadID = id; < K %j  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 v 1.*IV5Y  
} 9O98Q6-s  
<@#PF$!  
w G!u+  
public void run() b-<HXn_Fd  
{ \U@3`  
while(nStartPos < nEndPos && !bStop) }DIF%}UK\  
{ =_d%=m  
ClUSrSp  
>mm' -P  
try{ hx!7w}[A  
URL url = new URL(sURL); (4+1lOd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a39hP*  
httpConnection.setRequestProperty("User-Agent","NetFox"); ijYvqZ_  
String sProperty = "bytes="+nStartPos+"-"; .ER98  
httpConnection.setRequestProperty("RANGE",sProperty); N}Vn;29  
Utility.log(sProperty); _m'ysCjA  
fE;Q:# Z.  
Q:o 7G|C  
InputStream input = httpConnection.getInputStream(); P]6}\ ]~  
//logResponseHead(httpConnection); ([k7hUP  
3LK%1+)4  
$kz!zjC'  
byte[] b = new byte[1024]; Fb_S&!  
int nRead; 2CLB1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) GjQfi'vCk  
{ U}AX0*S  
nStartPos += fileAccessI.write(b,0,nRead); WH$HI/%*m  
//if(nThreadID == 1) %$mjJw<|&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kBsXfVs9  
} nX5C< Ky  
v5$s#f<   
x>3@R0A 1:  
Utility.log("Thread " + nThreadID + " is over!"); ")`S0n5e  
bDownOver = true; lOerrP6f(  
//nPos = fileAccessI.write (b,0,nRead); bhg}-dto  
} 2{o10 eL  
catch(Exception e){e.printStackTrace ();} z hsx &  
} ok0X<MR!I  
} |f' 8p8J  
sdr.u  
Xr_pgW|  
//打印回应的头信息 +_mr  
public void logResponseHead(HttpURLConnection con) HeIS;gfUY  
{ G$=-,6kZO  
for(int i=1;;i++) y-+G wa3  
{ @$U e$  
String header=con.getHeaderFieldKey(i);  ]PX}b  
if(header!=null) Z)9R9s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %e=!nRc  
Utility.log(header+" : "+con.getHeaderField(header)); T\sNtdF`:  
else (B#(Z=  
break; C0m\SNR  
} Q7a(P  
} ?q$P>guH6-  
'2v f|CX  
P6Xp<^%E  
public void splitterStop() w|Qd`  
{ S+T|a:]\7  
bStop = true; X"/~4\tJ"  
} =/Juh7[C  
uqZ3Hyb  
^gg!Me  
} E(Gr0#8  
eyB_l.U7  
F(4yS2h(  
/* rsxRk7s@  
**FileAccess.java _s>^?x}  
*//文件访问(定位,写) 3,$iG e  
package NetFox; WU\m^!`w=F  
import java.io.*; F`& >NQb  
Eo=HNe  
}$aNOf%:  
public class FileAccessI implements Serializable{ I'InZ0J2  
AQh["1{yJ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 H1T~u{8j}  
RandomAccessFile oSavedFile; K H}t:m+h  
long nPos; uPDaq ]A  
VS`Z_Xn  
gCV rC  
public FileAccessI() throws IOException 0wvU?z%WK  
{ s]x2DH+_  
this("",0); j|4tiv>  
} |- OHve4A  
Xj ,j0  
e_.~n<=  
public FileAccessI(String sName,long nPos) throws IOException yq6LH   
{ ETelbj;0  
oSavedFile = new RandomAccessFile(sName,"rw"); ^5x4q  
this.nPos = nPos; n\>.T[$"  
oSavedFile.seek(nPos); V9{B}5KC  
} t2.juoI(  
pqfT\Kb>  
NG)7G   
public synchronized int write(byte[] b,int nStart,int nLen) k?-S`o%Q  
{ @:gl:mc  
int n = -1; ^[TOZXL`:  
try{ *k6$   
oSavedFile.write(b,nStart,nLen); (Y;'[.  
n = nLen; 8IOj[&%0  
} B;c=eMw  
catch(IOException e) *vs~SzF$  
{ 3@HIpQM3  
e.printStackTrace (); Pz {Ig  
} 7'UWRRsxUF  
|"\lL9CT  
a71}y;W  
return n; ~UW{)]_jox  
} Q9q9<J7j$  
FB!z#Eim  
va+m9R0  
} =n)#!i  
GfNWP  
h@Dw'w  
/* W_D%|Ub2X  
**SiteInfoBean.java C~_q^fXJt  
*/ hvcR.f)C>  
package NetFox; Cha?7F[xL  
d<?X3&J  
6#-Z@fz%  
public class SiteInfoBean { 1eF@_Y^a!  
,whM22Af~{  
%w@ig~vD'  
private String sSiteURL; //Site's URL ASM1Y]'Z  
private String sFilePath; //Saved File's Path .lG +a!)  
private String sFileName; //Saved File's Name _!;\R7]  
private int nSplitter; //Count of Splited Downloading File %\_h7:  
gyg|Tno  
4sQ~&@[Q+  
public SiteInfoBean() Bf(Mot^  
{//nSplitter的缺省值为5 )w@y(;WJ  
//default value of nSplitter is 5 qIk )'!Vk  
this("","","",5); ]o!&2:'N`  
} 'F6#l"~/  
v6(,Ax&  
^EUQ449<p  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^ CX,nj_(  
{ /Sh4pu"'  
sSiteURL= sURL; {{GHzW  
sFilePath = sPath; LVWxd}0  
sFileName = sName; yOM -;h  
this.nSplitter = nSpiltter; h!~|6nj  
p+5#dbyr  
+E `063  
} <WgG=Kf)N  
6yi/&#YM  
:e52hK1[T  
public String getSSiteURL() -ca]Q|m8  
{ %pM :{Z  
return sSiteURL; @]<DR*<  
} eb(m8vLR  
>4#tkv>S.  
&a~L_`\'  
public void setSSiteURL(String value) C`z;,!58%  
{ =b|)Wnt2f  
sSiteURL = value; BD?F`%-x  
} J$<:/^t  
,at-ci\'  
<"{+  
public String getSFilePath() = c/3^e  
{ O]4W|WI3  
return sFilePath; #SK#k<&P  
} U8U/?zW/&  
E^'C "6  
^JiaR)#r  
public void setSFilePath(String value) ByC1I.B`  
{ WJBW:2=;  
sFilePath = value; (#CB q  
} EPR(i#xU  
Qdh"X^^  
GF9ZL  
public String getSFileName() moZ)|y  
{ {lTR/  
return sFileName; H,/~=d: ^  
} /{49I,  
e=YO.HT  
gE-lM/w  
public void setSFileName(String value) {Nzmb|&  
{ DKf}47y  
sFileName = value; t=AE7  
} |~Htj4K/  
LAOdH/*:  
z2"2tFK  
public int getNSplitter() W8\PCXnsfl  
{ 3T Yo  
return nSplitter; xuw//F  
} <x.]OZgO  
F%Ro98?{  
_ +0uju?o}  
public void setNSplitter(int nCount) eimA *0Cq  
{ pqRO[XEp2  
nSplitter = nCount; v GulM<YY  
} N8u_=b{X  
} hXj* {vT  
>Lo6='G  
4'd;'SvF  
/* k4]R]=Fh.  
**Utility.java ksxO<Y  
*/ ]Hv*^Bak  
package NetFox; n-L]YrDPK[  
K gR1El. r  
HCfS)`  
public class Utility { hqwz~Ky}  
3ZT/>a>@  
0e[ tKn(  
public Utility() L|dab {9  
{ WW,r9D:/  
\" 5F;J  
!nZI? z;  
} a3DoLq"/  
W]C_oh  
//线程睡眠 LRfFn^FPM  
public static void sleep(int nSecond) /It.>1~2@  
{ FE^?U%:u@  
try{ D0,oml  
Thread.sleep(nSecond); }bj,&c  
} )w3XN A_V  
catch(Exception e) i2\\!s  
{ &kmd<  
e.printStackTrace (); +dPE!:  
} OsHkAI  
} PW~cqo B71  
.q~,.yI&j  
//日志 ~7eUt^SD;  
public static void log(String sMsg) qHcY 2LV  
{ q? gQ  
System.err.println(sMsg); *NX*/(Q  
} *$*nY [/5  
iq[2H$  
o} bj!h]N  
public static void log(int sMsg) #I*ht0++  
{ 7csl1|U  
System.err.println(sMsg); /3"e3{u y  
} oIu,rjb  
} o i,g  
q%)*,I<  
=~(LJPo6  
/* yF [@W<  
**TestMethod.java )BMWC k  
*/ l{%Op\  
package NetFox; $6]x,Ct  
m+G0<E%  
 9\W5   
public class TestMethod { ~-o^eI4_  
:\ON+LQr  
8B% O%*5`  
public TestMethod() ^.><t+tM  
{ ///xx/weblogic60b2_win.exe ` Q!FMv6Y^  
try{ o@Cn_p^X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ? ><   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $`+~QR!h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); F".IB^} $  
fileFetch.start(); joSr,'x  
} 1)c=15^  
catch(Exception e){e.printStackTrace ();} Vq;{+j(  
N5I W@?4  
B@~eBU,$  
} njx\$,ruN  
O#89M%  
p-i]l.mT5  
public static void main(String[] args) *T}dv)8  
{ 6nhfI\q3wY  
new TestMethod(); V~%WKQ  
} /*xmv $  
} eyl) uR  
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