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http断点续传简单实现(java)

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/* F(!9;O5J]  
**SiteFileFetch.java -rn%ASye  
*/ QD2;JI2  
package NetFox; ]0Y5 Z)3:z  
import java.io.*; O,a1?_m8  
import java.net.*; -2o_ L?  
DG%vEM,y  
v(|Arm?  
public class SiteFileFetch extends Thread { `>i8$q%  
@N tiT,3k  
%< ^IAMkp  
SiteInfoBean siteInfoBean = null; //文件信息Bean k H.e"e  
long[] nStartPos; //开始位置 Vx gP^*  
long[] nEndPos; //结束位置 (_9u<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;hz;|\ko5  
long nFileLength; //文件长度 ^~ 95q0hq:  
boolean bFirst = true; //是否第一次取文件 5_H`6-q  
boolean bStop = false; //停止标志 _l{`lQ}  
File tmpFile; //文件下载的临时信息 *VuiEBG  
DataOutputStream output; //输出到文件的输出流 >/BMA;`  
AmyZ9r#{  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) !R`E+G@   
public SiteFileFetch(SiteInfoBean bean) throws IOException 8M<\?JD~_f  
{ jTeHI|b  
siteInfoBean = bean; "j2th.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); S S)9+0$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); IonphTcU!  
if(tmpFile.exists ()) #YiphR&  
{ 51sn+h<w  
bFirst = false; :637MD>5lO  
read_nPos(); MWl2;qi  
} )z" .lw  
else %X5p\VS\7  
{ mqt$'_M  
nStartPos = new long[bean.getNSplitter()]; ^MXW,xqb  
nEndPos = new long[bean.getNSplitter()]; y#B4m`9  
} ~x-"?K  
D&dh>Pe1;  
^t 2b`n60  
6E)emFkQ  
} TJO?BX_9  
GJ9'i-\*\  
`K%f"by  
public void run() a'Vz|S G  
{ ?LwBF;Y  
//获得文件长度 H(QbH)S$6  
//分割文件 K Y=$RO  
//实例FileSplitterFetch ^b;3Jj  
//启动FileSplitterFetch线程 0XSMby?t`  
//等待子线程返回 ` P,-NVB  
try{ O>KrTK-AV  
if(bFirst) x+Ws lN 2a  
{ : Yb_  
nFileLength = getFileSize(); ZL7#44  
if(nFileLength == -1) "Dt: 8Nf^  
{ ns&3Dh(IVP  
System.err.println("File Length is not known!"); x@p1(V.  
} u]766<Z  
else if(nFileLength == -2) ]YciLc(  
{ {0o ,2]o!:  
System.err.println("File is not access!");  >7$h  
} <K:L.c!  
else {Qf/.[  
{ 9<|nJt  
for(int i=0;i<nStartPos.length;i++) Gf->N `N  
{ l:.q1UV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Ai*+LSG  
} 1C5~GI`  
for(int i=0;i<nEndPos.length-1;i++) JYK 4/gJ  
{ EJid@  
nEndPos = nStartPos[i+1]; SR$?pJh D%  
} %_L~"E 2e  
nEndPos[nEndPos.length-1] = nFileLength; O' ~>AC5{  
} INRP@Cp1  
} PiVp(; rtQ  
KKRj#m(:!  
0hpU9w}12  
//启动子线程 s}93nv*ez  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; O4g2s8k  
for(int i=0;i<nStartPos.length;i++) \hO}3;*&  
{ c$n`=NI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .5E6 MF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p6&6^v\  
nStartPos,nEndPos,i); ']:>Ww.S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bCg)PJuB  
fileSplitterFetch.start(); rUW/d3y  
} IQ $/|b/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }? :T*CJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g@Z7f y7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #ULzh&yO  
nEndPos = " + nFileLength); b(Nxk2uv  
// fileSplitterFetch[nPos.length-1].start(); peZ'sZ6  
g/W&Ap;qVL  
Da)H/3ii  
//等待子线程结束 n.b_fkZNr  
//int count = 0; )~{8C:  
//是否结束while循环 *?x[pqGq  
boolean breakWhile = false; er0y~  
9&"wfN N  
vWZ?*0^  
while(!bStop) A5IW[Gu!  
{ w\}Q.$@  
write_nPos(); ,c&%/"i:w  
Utility.sleep(500); O|mWQp^?q  
breakWhile = true; p_EWpSOt7  
8=,?B h".  
Ro.br:'Bw  
for(int i=0;i<nStartPos.length;i++) P_F0lO  
{ }Ryrd!3bY  
if(!fileSplitterFetch.bDownOver) [l*;+N+  
{ Ewa/6=]LA  
breakWhile = false; &`2$,zX#  
break; LJwy,-  
} _X~xfmU  
} }Sh3AH/  
if(breakWhile) /y3Lc.-  
break; }PX8#C_P  
fU>4Ip1?y/  
`G<|5pe  
//count++; o9+fA H`D  
//if(count>4) H03R?S9AQ  
// siteStop();  , D}  
} @ [<B:Tqo  
:+v4,=fHy  
d:g0XP  
System.err.println("文件下载结束!"); _}l7f  
} X_(n  
catch(Exception e){e.printStackTrace ();} b" kL)DL1L  
} >/9Qgyc 0  
~mvD|$1z  
Q[&CtM  
//获得文件长度 X8 A$&  
public long getFileSize() +<^c2diX  
{ T1A/>\Ns  
int nFileLength = -1; t $u.  
try{ Io4Ss1="  
URL url = new URL(siteInfoBean.getSSiteURL()); t]XF*fZH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8S@"6TG`  
httpConnection.setRequestProperty("User-Agent","NetFox"); )E}eK-Yu  
blmY=/]  
VX'G\Zz@h|  
int responseCode=httpConnection.getResponseCode(); [-hsG E  
if(responseCode>=400) @ 5V3I^  
{ )vD|VLV   
processErrorCode(responseCode); [g@ .dr3t  
return -2; //-2 represent access is error *|S{%z9>  
} 7,2#0Z`ge  
) B[S4K2  
tWI %P&b  
String sHeader; <]u]rZc$  
hOr4C4  
<(x!P=NM-  
for(int i=1;;i++) nzl3<Ar  
{ :Y[?@/m4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {TC_ 4Y|8  
//Utility.log(in.readLine()); hEfFMi=a`  
sHeader=httpConnection.getHeaderFieldKey(i); Z#flu Q%V  
if(sHeader!=null) T-.Bof(?w  
{ jWGX :XB  
if(sHeader.equals("Content-Length")) wQrD(Dv(yA  
{ RO.bh#A$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); : G0^t  
break; FK,Jk04on  
} DX<xkS[P  
} ;s w3MRJ  
else 'ExTnv ~  
break; %P`|kPW1  
} l/6(V:  
} 0r%,|FaS  
catch(IOException e){e.printStackTrace ();} `YK%I8  
catch(Exception e){e.printStackTrace ();} Vv.q{fRvYB  
5`f\[oA  
D|"^ :Gi  
Utility.log(nFileLength); KZI-/H+  
k^Uk= )9  
E>NL/[1d  
return nFileLength; v$EgVc K  
} j?s+#t  
xi!R[xr1  
{>zQW{!  
//保存下载信息(文件指针位置) 7w5 L?,a  
private void write_nPos() \:_!!   
{ 5dEek7wnf  
try{ y*5$B.u`.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); jrm L>0NZ  
output.writeInt(nStartPos.length); \j~LxV  
for(int i=0;i<nStartPos.length;i++) I.'sK9\Zp  
{ xXNL UP  
// output.writeLong(nPos); W=?s-*F[~  
output.writeLong(fileSplitterFetch.nStartPos); <dX7{="&  
output.writeLong(fileSplitterFetch.nEndPos); ZO!)G   
} zXT[}J VV  
output.close(); '-KrneZ!  
} KGsW*G4U=  
catch(IOException e){e.printStackTrace ();} Fhbp,CX4p  
catch(Exception e){e.printStackTrace ();} d;LBV<Z?  
} Tsl0$(2W  
|p @,]c z  
m; m4/z3U  
//读取保存的下载信息(文件指针位置) GoRSLbCUR  
private void read_nPos() P:tl)ob  
{ a3(q;^v  
try{ H_+!.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6ZwFU5)QE/  
int nCount = input.readInt(); q@&.)sLPgO  
nStartPos = new long[nCount]; UZ3oc[#D=]  
nEndPos = new long[nCount]; =]hPX  
for(int i=0;i<nStartPos.length;i++) e(;nhU3a*,  
{ I DtGtkF  
nStartPos = input.readLong(); Zmr*$,v<y  
nEndPos = input.readLong(); sp&)1?!M  
} bx%P-r31  
input.close(); .LEn~ 8  
} 2 NrMse  
catch(IOException e){e.printStackTrace ();}  o0Pc^  
catch(Exception e){e.printStackTrace ();} ^g*2jH+  
} #e(P~'A0  
2_#V w&v  
62z"cFN  
private void processErrorCode(int nErrorCode) h]#bPb  
{ pxO ?:B  
System.err.println("Error Code : " + nErrorCode); ]WP[hF  
} DeL7sU  
nLv"ON~  
yct^AN|%  
//停止文件下载 WMXk-?v4  
public void siteStop() <-m?l6  
{ uZ7~E._  
bStop = true; ziBg'  
for(int i=0;i<nStartPos.length;i++) L?p,Sy<RI  
fileSplitterFetch.splitterStop(); d!]fou  
Kh;jiK !  
=_Y#uE$  
} ~LuR)T=%es  
} Xv1mjHZCC  
//负责部分文件的抓取 qOd*9AS'|M  
**FileSplitterFetch.java =/]d\JSp  
*/ ,6FmU$ Kn  
package NetFox; ,c\3b)ax  
0(~,U!g[=  
3-Xc3A=w  
import java.io.*; Ib665H7w  
import java.net.*; 3gzcpFNqX  
v5!G/TZ1  
y vz2eAXa  
public class FileSplitterFetch extends Thread { FD*w4U5  
, ,=7deR  
><Z`) }f  
String sURL; //File URL ;p}X]e l}  
long nStartPos; //File Snippet Start Position 0/Wo":R:  
long nEndPos; //File Snippet End Position LV X01ox$  
int nThreadID; //Thread's ID p .^#mN  
boolean bDownOver = false; //Downing is over 7ZVW7%,zF  
boolean bStop = false; //Stop identical T2V# fYCc  
FileAccessI fileAccessI = null; //File Access interface iSz?V$}?  
'aoHNZfxw  
;'x\L<b/)  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q[w.[]  
{ ntT~_Ba8;u  
this.sURL = sURL; d5ivtK?  
this.nStartPos = nStart; j*aYh^  
this.nEndPos = nEnd; 7JI&tlR4\c  
nThreadID = id; E5}wR(i,4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 l;gj],*  
} Ie%twc  
/K./k!'z  
(}C%g{8  
public void run() .`ppp!:a4  
{ ,`lVB#|  
while(nStartPos < nEndPos && !bStop) ^%qh E8  
{ .g6DKjy>  
M~1 n#  
x>yeF,q1  
try{ 8O5@FU 3  
URL url = new URL(sURL); _4VS.~}/R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); + ^9;<>P  
httpConnection.setRequestProperty("User-Agent","NetFox"); i+z;tF`  
String sProperty = "bytes="+nStartPos+"-"; wEImpsC`  
httpConnection.setRequestProperty("RANGE",sProperty); CdN,R"V0$@  
Utility.log(sProperty); ^Q\O8f[u  
"?~u*5  
:RnFRAcr  
InputStream input = httpConnection.getInputStream(); ped3}i+|]  
//logResponseHead(httpConnection); K&WNtk3hT  
!hJ% :^ xL  
%hu] =  
byte[] b = new byte[1024]; *?#t (Y[  
int nRead; ,^_aqH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  p|D-ez8  
{ `jur`^S|  
nStartPos += fileAccessI.write(b,0,nRead); = yH#Iil  
//if(nThreadID == 1) #!%\97ZR  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }m~2[5q%/  
} p<@0b  
O!(FNv0  
!PfIe94{`  
Utility.log("Thread " + nThreadID + " is over!"); ir4uy  
bDownOver = true; n./onv  
//nPos = fileAccessI.write (b,0,nRead); fJ?$Z|  
} 2@(Qd3N(  
catch(Exception e){e.printStackTrace ();} !:[kS1s>M  
} tilL7  
} 79>8tOuo  
`euk&]/^.)  
+=y ktf  
//打印回应的头信息 ms%Ot:uA  
public void logResponseHead(HttpURLConnection con) o9:GKc  
{ F+`DfI]/m  
for(int i=1;;i++) IJ%S[>  
{  jJjD)  
String header=con.getHeaderFieldKey(i); *Iu .>nw  
if(header!=null) Zh WtY  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); # Z*nc0C  
Utility.log(header+" : "+con.getHeaderField(header)); a?IL6$z  
else K_J o^BZ  
break; Xj\SJ*  
} o'3t(dyyH  
} Xjal6e)[  
aeESS;JxJj  
A|BvRZd  
public void splitterStop() nx(O]R,Sw  
{ L}&U%eD  
bStop = true; wNuS'P_(:T  
} p1=sDsLL  
h<wF;g,  
"/).:9],}  
} 9^m&  [Z  
4:=eO!6  
`nO!_3  
/* S? }@2[  
**FileAccess.java RN?z)9!  
*//文件访问(定位,写) ;mXr])J  
package NetFox; /:a~;i  
import java.io.*; 4ifWNL^)  
7CGKm8T  
W"mkNqH  
public class FileAccessI implements Serializable{ #![i {7  
Ml)Xq-&wc  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 "R$ee^  
RandomAccessFile oSavedFile; JF>mybB  
long nPos;  ##7,  
2#nn}HEOC  
n8zh;vuJ  
public FileAccessI() throws IOException w+cI0lj  
{ 1rV?^5  
this("",0); {PHxm  
} ybtje=3E  
}6P]32d  
P X](hc=  
public FileAccessI(String sName,long nPos) throws IOException _4z>I/R>Z  
{ K<b -|t9f  
oSavedFile = new RandomAccessFile(sName,"rw"); zxCxGT\;  
this.nPos = nPos; nTSGcMI  
oSavedFile.seek(nPos); %D z|p]49!  
} %ma1LN[  
SvH=P !`+  
E'LkoyI  
public synchronized int write(byte[] b,int nStart,int nLen) l}X3uy S  
{ t-SGG{  
int n = -1; +fzZ\  
try{ u>(s .4]+  
oSavedFile.write(b,nStart,nLen); P%smX`v  
n = nLen; C ,Je>G  
} d]h[]Su/?  
catch(IOException e) &^th KXEC  
{ ]?U:8%  
e.printStackTrace (); J$PE7*NU  
} p/WEQ2   
 @4_CR  
&l%#OI}OE  
return n; 4EuZe:'X  
} tkWWR%c"  
aO'$}rDf$  
L[+65ce%*  
} 8|7fd|6~  
VLtb16|  
!.iA^D//]  
/* * Yov>lO  
**SiteInfoBean.java >k^=+  
*/ )zt*am;  
package NetFox; 52*zX 3  
^zqz$G#  
<?Fgm1=o  
public class SiteInfoBean { v}-'L#6  
z@&_3 Gl  
R\yw9!ESd  
private String sSiteURL; //Site's URL ms3Ec`i9  
private String sFilePath; //Saved File's Path vVKiE 6^  
private String sFileName; //Saved File's Name 1O9V Ej5  
private int nSplitter; //Count of Splited Downloading File e )\s0#  
+(r8SnRX  
jKQnox+=  
public SiteInfoBean() T:wd3^.CG  
{//nSplitter的缺省值为5 eUqsvF}l!  
//default value of nSplitter is 5 &cDnZ3Q;  
this("","","",5); pz?.(AmU\  
} sJ?Fque  
Oa7`Y`6  
L4S Fu.J'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) z -(dT  
{ blaxUP:  
sSiteURL= sURL; Z/hSH 0(~  
sFilePath = sPath; R^dAwt`.D  
sFileName = sName; m+DkO{8F  
this.nSplitter = nSpiltter;  2c!?!:s  
W3 2mAz;  
Ik=KEOz  
} I2|iqbX40Q  
~oT0h[<  
Cb.~Dv !  
public String getSSiteURL() KWy4}7a@,s  
{ X"8Jk 4y  
return sSiteURL; tTF/$`Q#*  
} H*yX Iq:  
PWLMux  
>F,~QHcz  
public void setSSiteURL(String value) v"_hWJ)  
{ &hd+x5  
sSiteURL = value; z7{b>oub('  
} r6 ,5&`&  
8Z/P<u  
4<Bj;1*4  
public String getSFilePath() kHX- AsRc  
{ 5@Ot@o  
return sFilePath; !K(0)~u  
} ]_|qv1K6  
vYmRW-1Zxq  
FL0(q>$*8  
public void setSFilePath(String value) $+S'Boo   
{ l4hC>q$T  
sFilePath = value; '!{zO" 1*  
}  $C(}  
8K6yqc H  
Gnj|y?'  
public String getSFileName() D19uI&U4  
{ gjvKrg  
return sFileName; vlm&)DIt  
} "-A@>*g  
RjSVa.x  
#<4h Y7/  
public void setSFileName(String value) *Yl9%x]3c  
{ "J%u !~  
sFileName = value; <d$|~qS_  
} ^#lPXC Bg  
n/S1Hae`  
~naL1o_FZ  
public int getNSplitter() h+CTi6-p  
{ ,V.X-`Y  
return nSplitter; 5sFp+_``  
} [=7|LH jU  
#s)6u?N  
kVy%y"/  
public void setNSplitter(int nCount) @aY 8VL7C0  
{ & 2>W=h  
nSplitter = nCount; +<|6y46  
} z[}[:H8  
} =+'4u  
rC[*x}  
g15e|y)th  
/* j5G8IP_Wx  
**Utility.java `kVy1WiY  
*/ m+"?;;s  
package NetFox; L @t<%fy@  
Z-*L[  
M7fw/i  
public class Utility { 80&JEtRh  
%W+*)u72(  
!d&K,k  
public Utility() ;6U=fBp7<  
{ K82pWpR  
)(_}60  
sZFjkfak  
} M@E*_U!U  
*(PGL YK  
//线程睡眠  l}5@6;}  
public static void sleep(int nSecond) yO]Vex5)  
{ GFYAg  
try{ loLQ@?E  
Thread.sleep(nSecond); op/HZa  
} 0}PW<lU-  
catch(Exception e) 7^ITedW@  
{ >|/NDF=\s  
e.printStackTrace (); 7Xw;TA  
} # ~} 26  
} `QnKal)  
)d2 <;c  
//日志 k*w]a  
public static void log(String sMsg) Ky8sLm@  
{ im Zi7o  
System.err.println(sMsg); 3uZY.H+H  
} ^j0Mu.+_  
~kD/dXt  
UMma|9l(i  
public static void log(int sMsg)  -*_D!  
{ k>FMy#N|@  
System.err.println(sMsg); +=)< Su.  
} (I IPrW;>  
} #Ne<=ayS  
gah3d*d7  
8 T):b2h  
/* sbjAZzrX2i  
**TestMethod.java (/a2#iW  
*/ <IC=x(T  
package NetFox; 26G2. /**<  
SsIy;l  
1y2D]h/'  
public class TestMethod { {Uz@`QO3  
9gZMfP  
C},;M @xV  
public TestMethod() w-C ~ Ik  
{ ///xx/weblogic60b2_win.exe TUw^KSa  
try{ u}\F9~W-{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }/nbv;)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X};m\Bz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); r/$+'~apTk  
fileFetch.start(); =!w5%|r.  
} v~H1Il_+  
catch(Exception e){e.printStackTrace ();} mS p -  
.{1G"(z  
{0nZ;1,m  
} yM}}mypS  
#g#vDR!  
#v0"hFOH,  
public static void main(String[] args) *p`0dvXG2  
{ /`Yy(?,  
new TestMethod(); 5Q#;4  
} w},' 1  
} DJ_,1F  
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