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http断点续传简单实现(java)

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/* 6A*k  
**SiteFileFetch.java $ru()/pI)z  
*/ fKjUEMRK  
package NetFox; oJbMUEQQq  
import java.io.*; w8>  
import java.net.*; t&L+]I'P3  
)H`1CcT  
p:CpY'KV_  
public class SiteFileFetch extends Thread { D+xHTQNTL  
Y76UhtYH  
!pG_MO  
SiteInfoBean siteInfoBean = null; //文件信息Bean i\z,)xp  
long[] nStartPos; //开始位置 .iXI oka  
long[] nEndPos; //结束位置 jj8h>"d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ht!]%  
long nFileLength; //文件长度 S1oP_A[|  
boolean bFirst = true; //是否第一次取文件 Qfd4")zhG  
boolean bStop = false; //停止标志 13KfI  
File tmpFile; //文件下载的临时信息 'Z=8no`<  
DataOutputStream output; //输出到文件的输出流 y0f"UH/   
yJG M"$  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) GI$7uR}  
public SiteFileFetch(SiteInfoBean bean) throws IOException / 1R` E9  
{ t>izcO  
siteInfoBean = bean; )Me$BK>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); TSHQ>kP  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1Xj>kE:  
if(tmpFile.exists ()) *aT\V64  
{ ?7"6d p_K  
bFirst = false; =w <;tb  
read_nPos(); sGs_w:Hn  
} Y}Gf%Xi,  
else YdNmnB %J  
{ lay)I11- >  
nStartPos = new long[bean.getNSplitter()]; ,2?Sua/LD  
nEndPos = new long[bean.getNSplitter()]; I# U"DwM  
} E ) iEWc  
|SfmQ;  
jX8,y  
p a)2TL/@  
} z),@YJU"z  
8C(@a[V  
5fqQ;r  
public void run() "hi)p9 _cR  
{ /a:sWmxMT  
//获得文件长度 sp'f>F2]  
//分割文件 d iGkwKj  
//实例FileSplitterFetch 236,o {9e  
//启动FileSplitterFetch线程  8%W(",nd  
//等待子线程返回 ! >l)*jN8  
try{ V$';B=M  
if(bFirst) i r/-zp_  
{ MX\v2["FoV  
nFileLength = getFileSize(); zv}3Sl@  
if(nFileLength == -1) P>s 3Rh3:  
{ F vt5vQ  
System.err.println("File Length is not known!"); ;+-M+9"?O  
} y2:~_MD  
else if(nFileLength == -2) "{F e  
{ Oj~4uT&"  
System.err.println("File is not access!"); m^M sp:T,  
} +#a_Y  
else \Q m1+tg  
{ c^ifHCt|  
for(int i=0;i<nStartPos.length;i++) 9yt)9f  
{ RC>79e/u<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); G&2`c\u{  
} ;H;c Sn5uL  
for(int i=0;i<nEndPos.length-1;i++) o,yP9~8\  
{ 1o*eu&@  
nEndPos = nStartPos[i+1]; :497]c3#5C  
} pX~X{JTaL)  
nEndPos[nEndPos.length-1] = nFileLength; gJUawK  
} ndCHWhi  
} &W@#p G  
K[~fpQGbV1  
mv;;0xH  
//启动子线程 -{ M(1vV(=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Hk8pKpn3  
for(int i=0;i<nStartPos.length;i++) `C+>PCO  
{ 1U(P0$C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8+yC P_Y4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ] eO25,6  
nStartPos,nEndPos,i); Dq:>]4%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +i0j3.  
fileSplitterFetch.start(); 8pZGu8  
} mufJ@YS#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `: R7j f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7I0[Ii  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S(\<@S&  
nEndPos = " + nFileLength); w#Di  
// fileSplitterFetch[nPos.length-1].start(); MJDW-KL-  
44p?x8(z*  
ZS\~GQbG  
//等待子线程结束 V^[B=|56  
//int count = 0; Q]v><  
//是否结束while循环 8,DY0PGP  
boolean breakWhile = false; 9J $"Qt5;6  
2YV*U_\L  
oM~;du  
while(!bStop) e"@Ag:r@a  
{ ,N`cH\  
write_nPos(); 5_ \+8A*  
Utility.sleep(500); +IkL=/';#  
breakWhile = true; -Y=o  
@7j$$  
lI*uF~ 'D  
for(int i=0;i<nStartPos.length;i++) z 7 s&7)a  
{ (- QvlpZ  
if(!fileSplitterFetch.bDownOver) XJI ff$K  
{ 5H!6 #pqM  
breakWhile = false; 1@"os[ 9  
break; lc8zF5  
} abgA Ug)  
} DbIn3/W Ne  
if(breakWhile) W~i599!v  
break; =(cfo_B@K  
7(W"NF{r  
snm1EPj  
//count++; u#^~([ I  
//if(count>4) $FM: 8^  
// siteStop(); A]_5O8<buW  
} G%#M17   
/ho7O/aAa  
P'<D0   
System.err.println("文件下载结束!"); W0qn$H  
} >5c38D7k)  
catch(Exception e){e.printStackTrace ();} ?Zv>4+Y'  
} ["7]EW\!:  
>)6d~  
lV ra&5  
//获得文件长度 p/WE[8U  
public long getFileSize() .wvgH i  
{ $z[r (a^a  
int nFileLength = -1; kX8Ey  
try{ Q@aDa8Z  
URL url = new URL(siteInfoBean.getSSiteURL()); 1kdQh&~G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tYST&5Kh~  
httpConnection.setRequestProperty("User-Agent","NetFox"); |Zm'!-_  
JuM4Njz|  
O;C C(  
int responseCode=httpConnection.getResponseCode(); 1}XESAX;0  
if(responseCode>=400) 9JBVG~m+  
{ 25wvB@0&  
processErrorCode(responseCode); >uy(N  
return -2; //-2 represent access is error ;/s##7qf  
} &wea]./B  
Zg;%$ kSQ  
3"HX':8x  
String sHeader;  \s^4f#  
[Zj6v a  
Cj1nll8c  
for(int i=1;;i++) DR c-L$bD  
{ 5ji#rIAhxh  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }F=lG-x  
//Utility.log(in.readLine()); .h=H?Hr(V]  
sHeader=httpConnection.getHeaderFieldKey(i); m#a1N  
if(sHeader!=null) <4,LTB]9-  
{ g7@.Fa.u'!  
if(sHeader.equals("Content-Length")) 2{oU5e  
{ ;{:bq`56f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f*E#E=j  
break; V \Sl->:  
} a"bael  
} #.W^7}H  
else JthW"{E  
break; Q)L6+gW^  
} W~Ae&gcn#  
} v FWg0 $,  
catch(IOException e){e.printStackTrace ();} gBd@4{y6C.  
catch(Exception e){e.printStackTrace ();} dO!5` ]  
(_Ky' .  
1!p7N$QR  
Utility.log(nFileLength); * G0I2  
.F^372hH3  
7L !$hk  
return nFileLength; ;+(EmD:Q  
} .g8db d  
r";;Fk#5  
y|2y! &o,!  
//保存下载信息(文件指针位置) @l %x;`E  
private void write_nPos() G^&P'*  
{ b 67l\L  
try{ cu )w6!f  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wq = Ef  
output.writeInt(nStartPos.length); .ovG_O  
for(int i=0;i<nStartPos.length;i++) "?r_A*U  
{ >&D}^TMYY  
// output.writeLong(nPos); Xcw 6mpLt  
output.writeLong(fileSplitterFetch.nStartPos); NGL,j\(~7  
output.writeLong(fileSplitterFetch.nEndPos); Q~zs]{\  
} `FHKQS5  
output.close(); ?my2dd,|  
} aM!%EaT  
catch(IOException e){e.printStackTrace ();} )m<CmYr2  
catch(Exception e){e.printStackTrace ();} =)IV^6~b  
} Pt\GVWi_t  
HMl M!Xk?  
H}PZJf_E  
//读取保存的下载信息(文件指针位置) nk.j7tu  
private void read_nPos() FfpP<(4  
{ 'v0(ki#  
try{ 7 (pl HW|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i(an]%'v  
int nCount = input.readInt(); YF6 8 Ax]  
nStartPos = new long[nCount]; Ac8t>;=&  
nEndPos = new long[nCount]; vNSeNS@jxC  
for(int i=0;i<nStartPos.length;i++) Ee097A?1vj  
{ gH:+$FA  
nStartPos = input.readLong(); |?<^4U8  
nEndPos = input.readLong(); f`bRg8v  
} c$b~? Mx  
input.close(); {N'<_%cu  
} Y0xn}:%K  
catch(IOException e){e.printStackTrace ();} SI9PgC  
catch(Exception e){e.printStackTrace ();} ?G<.W[3  
} 49-wFF  
<Wa7$hF  
\Y^GA;AMQQ  
private void processErrorCode(int nErrorCode) "a=dx| Z  
{ ~U+W4%f8  
System.err.println("Error Code : " + nErrorCode); e!oL!Zg  
} z#Db~  
|"i"8~/@<  
Yx':~  
//停止文件下载 nNpXkI:  
public void siteStop() PsO>&Te2  
{ 3e ?J#;  
bStop = true; e_3($pj  
for(int i=0;i<nStartPos.length;i++) 5#B M  
fileSplitterFetch.splitterStop(); l dw!G/  
W,bu=2K6  
$*c!9Etl4  
} @BoZZ  
}  ?F/)<r  
//负责部分文件的抓取 .kp3<.  
**FileSplitterFetch.java Kdr} 7#c  
*/ sj8lvIY5  
package NetFox; dLtmG:II  
b:(t22m#?  
%6cbHH  
import java.io.*; bBgyLyg  
import java.net.*; {4YD_$4W  
4b  1a?  
"9O8#i<Nr  
public class FileSplitterFetch extends Thread { >gf,8flgj  
V#TNv0&0  
Z7J4r TA  
String sURL; //File URL I/)*pzt8  
long nStartPos; //File Snippet Start Position N?><%fra  
long nEndPos; //File Snippet End Position ~'VVCtA  
int nThreadID; //Thread's ID a Juv{  
boolean bDownOver = false; //Downing is over @Zw[LIQ*  
boolean bStop = false; //Stop identical mu$rG3M  
FileAccessI fileAccessI = null; //File Access interface (7w95xI  
K:54`UJ  
N4$ K {  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ls/*&u  
{ rj/1AK  
this.sURL = sURL; L!0}&i;u~5  
this.nStartPos = nStart; r;@"s g  
this.nEndPos = nEnd; SlI wLv^  
nThreadID = id; 2U& +K2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 x<1t/o  
} #+(@i|!ifo  
Rh%C$d(  
5`Y>!| Ab  
public void run() !dOpLUh l  
{ C=x70Y/  
while(nStartPos < nEndPos && !bStop) ,jdTe?[*^  
{ 52.%f+Oa  
349BQ5ND  
iiv`ji  
try{ C@!bd+'  
URL url = new URL(sURL); Dn:1Mtj-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _71&".A  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?$.x%G+  
String sProperty = "bytes="+nStartPos+"-"; cf%aOHYI*  
httpConnection.setRequestProperty("RANGE",sProperty); E'^ny4gL  
Utility.log(sProperty); SS!b`  
<[' ucp  
?\_vqW  
InputStream input = httpConnection.getInputStream(); lY[\eQ 1:  
//logResponseHead(httpConnection); @nOuFX4  
2[i(XG{/  
(&Mv!6]  
byte[] b = new byte[1024]; FZtT2Z4&i  
int nRead; L b-xc]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) N9 TM  
{ ;^cMP1SH  
nStartPos += fileAccessI.write(b,0,nRead); )WsR 8tk  
//if(nThreadID == 1) +2g}wH)l  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ta0;:o?/d  
} qJ[wVNHh!  
`. 3{  
,:% h`P_  
Utility.log("Thread " + nThreadID + " is over!"); {hVc,\A  
bDownOver = true; :eFyd`Syw  
//nPos = fileAccessI.write (b,0,nRead); *Rgl(Ba  
} /Nns3oE  
catch(Exception e){e.printStackTrace ();} %e+{wU}w?2  
} E&>;a!0b]  
} 9F7}1cH7g@  
XwDt8TxL  
Mo]aB:a  
//打印回应的头信息 >%A~ :  
public void logResponseHead(HttpURLConnection con) y(X^wC  
{ S^{tRPF%d  
for(int i=1;;i++) c3(0BSv  
{ s:ojlmPb  
String header=con.getHeaderFieldKey(i); YM#J_sy@J.  
if(header!=null) ]l^" A~va  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <K <|G  
Utility.log(header+" : "+con.getHeaderField(header)); <SiJA`(7  
else Lw`}o`D  
break; uTvf[%EHW  
} 0u bf]Z  
} SK 5__Ix  
zvwv7JtB  
}ISR +./+  
public void splitterStop() vHN/~k#  
{ \m(>Q  
bStop = true; MbeK{8~E%l  
} Z/LYTo$Bz  
9Us'Q{CD   
vdd>\r)v  
} \`W8#fob  
j43i:c;F  
rh T!8dTk  
/* Iv/h1j> H  
**FileAccess.java 83F]d+n  
*//文件访问(定位,写) u. 2^t :A  
package NetFox; ?ZYj5[op,H  
import java.io.*; p+V::O&&r  
\O)u' Bu  
$]MOAj"LH  
public class FileAccessI implements Serializable{ U04)XfO;]  
!, {-q)'D  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -BH T'zq1S  
RandomAccessFile oSavedFile; \~.elKw<U  
long nPos; n<Ki.;-ZE  
@%!Gj{   
Mo\nY5  
public FileAccessI() throws IOException z8 K#G%,:  
{ vH@$?b3VP  
this("",0); R)Dh;XA  
} o<rbC < U  
!L)yI#i4C  
`+(4t4@ew  
public FileAccessI(String sName,long nPos) throws IOException 7e /Kh)5G  
{ VM+l9 z>  
oSavedFile = new RandomAccessFile(sName,"rw"); G{0f* cH)  
this.nPos = nPos; !J(6E:,b#  
oSavedFile.seek(nPos); M1I4Ot  
} r@ba1*y0  
z5W;-sCz  
J7k=5Fqej;  
public synchronized int write(byte[] b,int nStart,int nLen) zwK$ q=-:  
{ W3&~[DS@~  
int n = -1; Ox6^=D "  
try{ TSj)XU {W  
oSavedFile.write(b,nStart,nLen); \b?O+;5Cj  
n = nLen; XlJ+:st  
} 1~[GGl  
catch(IOException e) ~e=KBYDBu  
{ S9 @*g3  
e.printStackTrace (); 5K00z?kD2V  
} M] W5 %3do  
10*^  
wV'_{ /WM  
return n; =<U'Jtu6'  
} sNJ?Z"5k1h  
P c vA/W  
F2v9 XMi  
} \$ :)Ka  
.&/A!3pW  
f0g&=k{OD  
/* \8`^QgV`@  
**SiteInfoBean.java kp*BAQ  
*/ H}lbF0`  
package NetFox; +'UxO'v3]  
t_Ul;HVPS  
+Q!Kj7EU/  
public class SiteInfoBean { (ewcj\l4*  
IXsOTBM  
/_r{7Gq.  
private String sSiteURL; //Site's URL a2H_8iQ!  
private String sFilePath; //Saved File's Path Q]-r'pYr  
private String sFileName; //Saved File's Name =GLMdhD]  
private int nSplitter; //Count of Splited Downloading File s_76)7  
I2C1mV  
l6!a?C[2T  
public SiteInfoBean() r`C t/]c  
{//nSplitter的缺省值为5 XNkQ0o0  
//default value of nSplitter is 5 7` t,   
this("","","",5); ? \NT'CG  
} 0!`!I0  
eb<' >a  
g= s2t"&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) X($@E!|  
{ ,@t#)HV  
sSiteURL= sURL; (ce"ED`1  
sFilePath = sPath; v9Ez0 :)  
sFileName = sName; bM $WU?Z  
this.nSplitter = nSpiltter; 'Y5=A!*@tf  
62#8c~ dL  
=4 W jb  
} k? =_p6>  
G_?qY#"(  
'deqF|Iox  
public String getSSiteURL() zuvP\Y=V`  
{ jce2lXMm  
return sSiteURL; n/IDq$/P  
} r-o6I:y  
!Ly1!;<  
j,#R?Ig  
public void setSSiteURL(String value) 7,3v,N|  
{ IF|%.%I$!U  
sSiteURL = value; x[2eA!NC  
} .?.Q[ic  
9|//_4]  
Q3x.qz  
public String getSFilePath() 2LH.If  
{ #NWc<Dd  
return sFilePath; /f -\ 3  
} JC4Z^/\.  
}C&kzJBEF  
.gd'<l  
public void setSFilePath(String value) j(\jYH>   
{ SL>0_  
sFilePath = value; O)G^VD s  
} U+g<lgH1J  
vjD||!g'  
on0>_-n)  
public String getSFileName() Y ptP_R:2p  
{ sTO9>~sj  
return sFileName; (1Ii86EP  
} !6d`e"\K  
z@J;sz  
lF!Iu.MM 9  
public void setSFileName(String value) -44''w?z  
{ !u|s| 6{\  
sFileName = value; Sc&p*G  
} #[Vk#BIiv8  
pJ]i)$M  
1fb!sbGD.k  
public int getNSplitter() `oo(\O7t=  
{ KR/SMwy  
return nSplitter; *7 >K"j  
} -AU!c^-o  
9~WjCa*,&  
yn-TN_/Y,  
public void setNSplitter(int nCount) L\X 2Olfz1  
{ 8p~G)J3U  
nSplitter = nCount; D[}qhDlX  
} VcR(9~  
} M]OZS\9.B  
4f> s2I&pQ  
%q 7gl;'  
/* n+uDg  
**Utility.java h^"OC$  
*/ I%31MU9  
package NetFox; pwO U6A!  
j#E&u*IR  
|\ 4cQ  
public class Utility { B":u5_B  
W02swhS  
4PAuEM/z  
public Utility() <',bqsg[  
{ Lj03Mx.2S  
Vt D:'L-  
 6,;7iA]  
} FrryZe=  
@^kt[$X;  
//线程睡眠 KN9e""  
public static void sleep(int nSecond) Acib<Mi2!-  
{ 5 MD=o7O^  
try{ tB7g.)yZb  
Thread.sleep(nSecond); x(/{]$h  
} iSxuor ^;  
catch(Exception e) VVyms7 VN  
{ p8Wik<'^  
e.printStackTrace ();  MUd 9R  
} _ -/<bO  
} AjA.="3  
DQOEntw  
//日志 ",qJG]_ <  
public static void log(String sMsg) 9n[ovX 7n!  
{ s0x;<si_  
System.err.println(sMsg); #y&O5    
} L@HWm;aN  
n:wZL&ZV0  
Z>zW83a  
public static void log(int sMsg) G;3N"az  
{ OwM.N+ z#T  
System.err.println(sMsg); 1W +QcK4k  
} D/-$~u_o  
} c$HZvv  
Td6"o&0A!  
Fz4g:8qdA  
/* e[a?5,s2  
**TestMethod.java U}Aoz|  
*/ _Q1[t9P"  
package NetFox; >'X[*:Cx  
60 z =bd]  
 <c &6M  
public class TestMethod { / !*+9+h  
)2jBhT  
9c_h+XN?y  
public TestMethod() *N #{~  
{ ///xx/weblogic60b2_win.exe k)l^ ;x-  
try{ VU[4 W8f  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ry%Fs&V*>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #n8jn#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Wa|lWIMK  
fileFetch.start(); %"0g}tK6  
} -O?}-6,_Z  
catch(Exception e){e.printStackTrace ();} `Mp-4)mn  
z_LN*u  
&_N$S2  
} b\O%gg\p%!  
i>`!W|=_  
psZAO,p  
public static void main(String[] args) .\X;VWTI  
{ ^1^mu c[  
new TestMethod(); T1Q c?5K^  
} Tn7(A^h'  
} UoiXIf_Q  
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