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http断点续传简单实现(java)

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/* Ku,Efr  
**SiteFileFetch.java ,Hys9I  
*/ \,p)  
package NetFox; ?A62VV51CN  
import java.io.*; 1+#Vj#  
import java.net.*; Fdc bmQ  
0" R|lTYq  
`;cKN)Xk  
public class SiteFileFetch extends Thread { rX;(48Y  
.V/TVz!b  
1f[!=p  
SiteInfoBean siteInfoBean = null; //文件信息Bean 8{?Oi'-|0  
long[] nStartPos; //开始位置 D*D83z OzN  
long[] nEndPos; //结束位置 &rw|fF|]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 C:4h  
long nFileLength; //文件长度 P7u5Ykc*  
boolean bFirst = true; //是否第一次取文件 <PV @JJ"  
boolean bStop = false; //停止标志 [&FMVM`  
File tmpFile; //文件下载的临时信息 mhlJzGr*q  
DataOutputStream output; //输出到文件的输出流 k(VA5upCs  
aN;L5;m#>{  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Q~-gtEv+&  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7;|6g8=  
{ ;PS [VdV  
siteInfoBean = bean; dC,F?^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .6vQWt7@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); PFEi=}Y@((  
if(tmpFile.exists ()) lX5(KUN  
{ b GwLfU  
bFirst = false; /tt  
read_nPos(); d6hWmZVC  
} P\N`E?lJL  
else @*%.V.  
{ h+Dg"j<[  
nStartPos = new long[bean.getNSplitter()]; 3)Paf`mr  
nEndPos = new long[bean.getNSplitter()]; lfj>]om$  
} H.i_,ZF  
 Nu9mK  
KY|Q#i|pM  
[xI@)5Xk  
} .`)ICX  
||Lqx#e=  
^lf;Lc  
public void run() cHJ &a`;  
{ N{Is2Ia  
//获得文件长度 5,?9#n\E,  
//分割文件 .4-;  
//实例FileSplitterFetch ;AG5WPI  
//启动FileSplitterFetch线程 +8BH%f}X  
//等待子线程返回 ?'h@!F%R'  
try{ =gfLl1wY[  
if(bFirst) :1.$7W t  
{ /3+7a\|mKr  
nFileLength = getFileSize(); vNJ!i\bX  
if(nFileLength == -1) hsfVKlw-  
{ m! p'nP  
System.err.println("File Length is not known!"); 1YM04*H  
} GhpH7% s  
else if(nFileLength == -2) X.T.^}=  
{ YToRG7X#  
System.err.println("File is not access!"); $,h*xb.  
} t[an,3  
else ^$x^JM ]/  
{ pOS.`rSK  
for(int i=0;i<nStartPos.length;i++) 0Y!Bb2 m  
{ {W0]0_mI(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); % ;6e@U}  
} yiI&>J))  
for(int i=0;i<nEndPos.length-1;i++) qvYw[D#.  
{ gCwg ;c-  
nEndPos = nStartPos[i+1]; Z,u:g c+*  
} ld2 \/9+n  
nEndPos[nEndPos.length-1] = nFileLength; :&TOQ<vM  
} k# &y  
} >_&+gn${  
L"('gc!W  
gL}K84T$S  
//启动子线程 roRZE[ya  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }A2@1TTPX  
for(int i=0;i<nStartPos.length;i++) g7d)YUc  
{ $>#PhOC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /- kMzL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), X8*q[@$  
nStartPos,nEndPos,i); y'E)iI*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fNB*o={r|  
fileSplitterFetch.start(); k92189B9j/  
} y l3iU:+V  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t0?BU~f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  -JUv'fk  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", yY,.GzIjCj  
nEndPos = " + nFileLength); YjG0: 9  
// fileSplitterFetch[nPos.length-1].start(); [_H9l)  
$9ON 3>  
B>~E6j7[Mp  
//等待子线程结束 S!g&&RDx  
//int count = 0; <y`yKXzBUV  
//是否结束while循环 R8HA X  
boolean breakWhile = false; *(r85lEou)  
p]pFZ";70  
<pPI:D@G  
while(!bStop) P^1rNB  
{ r*,]=M W  
write_nPos(); :.sK:W("v  
Utility.sleep(500); 1S_ KX.  
breakWhile = true; }b,a*4pN  
nre8 F  
Grw_SVa^  
for(int i=0;i<nStartPos.length;i++) ][qZOIk@  
{ &|9?B!,`  
if(!fileSplitterFetch.bDownOver) h!)(R<  
{ %7V?7BE  
breakWhile = false; y0=BL  
break; a2 YdkdjT  
} AY *  
} G-} zkax  
if(breakWhile) !)&-\!M>  
break; y8,es$  
kuUH 2:L  
][0HJG{{g  
//count++; j[Et+V?  
//if(count>4) )ns;S  
// siteStop(); 8K1+ttjm  
} \>jK\j  
fxiq,o0  
)fCl<KG*  
System.err.println("文件下载结束!"); Kk??}  
} JXvHsCd?  
catch(Exception e){e.printStackTrace ();} &=s{ +0  
} DpTQPu9  
3HfT9  
-98bX]8  
//获得文件长度 ;N4mR6  
public long getFileSize() wV(_=LF  
{ dn5T7a~   
int nFileLength = -1; /+66y=`UJ  
try{ /=-E`%R}!  
URL url = new URL(siteInfoBean.getSSiteURL()); 2U#OBvNU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @c.QrKSaD  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xv'64Nc!;  
tc# rL   
r4_ c~\jH  
int responseCode=httpConnection.getResponseCode(); ,@>B#%Nz  
if(responseCode>=400) !X#=Pt[,  
{ y6G[-?"/Q  
processErrorCode(responseCode); R4qS,2E  
return -2; //-2 represent access is error =8<SKY&\X  
} V:IoeQ]-  
[;tbNVZK  
{qh`8  
String sHeader; LfK <%(:  
3 #jPQ[+  
"h)+fAT|,  
for(int i=1;;i++) tb_}w@:kU  
{ 6%:'2;xM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ou,B3kuQ+  
//Utility.log(in.readLine()); &Cdd  
sHeader=httpConnection.getHeaderFieldKey(i); x#pT B.  
if(sHeader!=null) 1_<'S34  
{ zzPgLE55  
if(sHeader.equals("Content-Length")) ..n-&(c32  
{ 9-L.?LG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); h{>8W0W*  
break; `cVG_= 2  
} |@Z QoH  
} B\N,%vsx#U  
else \7Zk[)!FL  
break; WRD^S:`BH  
} WXGLo;+>I  
} `)SkA?yKI  
catch(IOException e){e.printStackTrace ();} PRf2@0ZV  
catch(Exception e){e.printStackTrace ();} \d v9:X$  
Aja'`Mu  
k.0$~juu  
Utility.log(nFileLength); +fKLCzj  
o>j3<#?  
I,q3J1K  
return nFileLength; Z/a]oR@  
} *jDzh;H!w  
i\,#Z!  
<;_X=s`f,  
//保存下载信息(文件指针位置) |s s_<  
private void write_nPos() QvqX3FU  
{ ;i Ud3 '*  
try{ T#h`BtET[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6h;$^3x$  
output.writeInt(nStartPos.length); UG1^G07s  
for(int i=0;i<nStartPos.length;i++) = "Dmfy7  
{ n {^D_S  
// output.writeLong(nPos); ;2& (]1X  
output.writeLong(fileSplitterFetch.nStartPos); o2Z# 5-  
output.writeLong(fileSplitterFetch.nEndPos);  E#ti  
} X;zy1ZH  
output.close(); }X}fX#[  
} !9V_U  
catch(IOException e){e.printStackTrace ();} M|76,2u   
catch(Exception e){e.printStackTrace ();} j >P>MdZtk  
} BcA:M\dK%  
B;_M52-B  
5a4;d+  
//读取保存的下载信息(文件指针位置) et)A$'Q  
private void read_nPos() E[ e ''  
{ 8Gs{Zfp!D  
try{ N<O^%!buR  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *Q5/d9B8TN  
int nCount = input.readInt(); wYNh0QlBH  
nStartPos = new long[nCount]; ].` i`.T  
nEndPos = new long[nCount]; N "FQMxqm  
for(int i=0;i<nStartPos.length;i++) Z?1.Y7Npr  
{ -YRF^72+  
nStartPos = input.readLong(); 8]+hfB/  
nEndPos = input.readLong(); 8+ Hho@=  
} 'rU 5VrK  
input.close(); h.G/HHz  
} oXb}6YC  
catch(IOException e){e.printStackTrace ();} [%Y Cupr#  
catch(Exception e){e.printStackTrace ();} !a4pKN`qLY  
} H?^Poe(=(  
!=eui$]  
 ;-U :t4  
private void processErrorCode(int nErrorCode) X[|-F3o  
{ eX $u  
System.err.println("Error Code : " + nErrorCode); 42X[Huy]  
} 2z&HT SI  
QnVYZUgJeV  
\vojF\  
//停止文件下载 /R@eOl}D  
public void siteStop() &o:wSe  
{ 6uR :/PTG  
bStop = true; bi[vs|  
for(int i=0;i<nStartPos.length;i++) JZ80|-c  
fileSplitterFetch.splitterStop(); ?v `0KF  
[ 98)7  
lYD-U8  
} LB U]^t@ M  
} dsrzXmE0  
//负责部分文件的抓取 BTGPP@p4  
**FileSplitterFetch.java If2f7{b  
*/ _ jF, k>F  
package NetFox; M>8#is(pV  
#t po@pJsE  
*|ubH?71%Y  
import java.io.*; I}$Y[Jve  
import java.net.*; B0nkHm.Sj  
Ws.F=kS>h  
dk-Y!RfNx  
public class FileSplitterFetch extends Thread { 4GeWo@8h  
;1K.SDj  
~S#Le  
String sURL; //File URL )Q&:$]  
long nStartPos; //File Snippet Start Position 0P&rTtU6  
long nEndPos; //File Snippet End Position Z[Uz~W6M]  
int nThreadID; //Thread's ID 0ir]  
boolean bDownOver = false; //Downing is over ^JJ*pT:  
boolean bStop = false; //Stop identical qAHQZKk  
FileAccessI fileAccessI = null; //File Access interface >t3%-Kc  
T" XZ[q  
-7$7TD`'7  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException DMsxHAE1  
{ 7_ZfV? .  
this.sURL = sURL;  b-yfBO  
this.nStartPos = nStart; C.Y]PdYyj  
this.nEndPos = nEnd; kk )9!7  
nThreadID = id; F@)wi0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 M7BJ$fA0E  
} ^4h/6^b0c  
b~WiE?  
bK<'J=#1  
public void run() Mb"i}Yt{  
{ gW$X8ECX  
while(nStartPos < nEndPos && !bStop) `o)rAD^e  
{ %N=-i]+Id  
oj;Rh!O  
fiES6VL  
try{ QI.{M$,m~  
URL url = new URL(sURL); {D 9m// x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G;>b}\Ng  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9jCn|+  
String sProperty = "bytes="+nStartPos+"-"; &r;-=ASYzV  
httpConnection.setRequestProperty("RANGE",sProperty); TW7jp  
Utility.log(sProperty); q`{crY30  
oGu-:X=`9  
2dFC{US'  
InputStream input = httpConnection.getInputStream(); 48Vmz  
//logResponseHead(httpConnection); .|G([O^H  
vB hpD  
QcU&G*   
byte[] b = new byte[1024]; u|BD=4*  
int nRead; !Z 3iu  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) DwMq  
{ /YKg.DA|  
nStartPos += fileAccessI.write(b,0,nRead); [daUtKz  
//if(nThreadID == 1) x4r\cL1!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [>U'P1@ql  
} j;WZ[g#t  
/2Y t\=S=  
:&S6AP  
Utility.log("Thread " + nThreadID + " is over!"); h;u8{t"  
bDownOver = true; |$f.Qs~?  
//nPos = fileAccessI.write (b,0,nRead); &"p7X>bd  
} >ZTRwy`_(  
catch(Exception e){e.printStackTrace ();} kn:X^mDXC/  
} ?>92OuG%W?  
} ^7G@CBic"  
jgQn^  
8' M4 3n  
//打印回应的头信息 ]DHB'NOh,  
public void logResponseHead(HttpURLConnection con) u!S^lV@  
{ kc Q~}uFB  
for(int i=1;;i++) |_x U{Pu  
{ p%/Z  
String header=con.getHeaderFieldKey(i); LZG?M|(6D  
if(header!=null) _lcx?IV  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); k)U9 %Pr  
Utility.log(header+" : "+con.getHeaderField(header)); V^sZXdDNL  
else e`27 ?  
break; P-[6'mw`  
} Ha>Hb`  
} Ka%u#};  
gY9HEfB  
&FHzd/  
public void splitterStop() FZf{kWH  
{ /@h)IuW  
bStop = true; `@!4#3H  
} I?<5 %  
GTgG0Ifeh  
8vpB(VxV+  
} #e|G!'wdj  
~\B1\ G  
DyhW_PH2J  
/* Tk\?$n  
**FileAccess.java t@m!k+0  
*//文件访问(定位,写) OMgFp|^  
package NetFox; < Ih)h$8`  
import java.io.*; r {R879  
n]{sBI3  
Q"rQVO  
public class FileAccessI implements Serializable{ `>'%!E9G  
WD.td  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4}-{sS}MP  
RandomAccessFile oSavedFile; +||y/}1  
long nPos; jRdmQ mTJ  
h]W PWa)M  
.S4c<pMap  
public FileAccessI() throws IOException Y=0D[o8  
{ #2 Gy=GvV  
this("",0); ~nLE?>x|Z  
} %+gK5aVab  
%QYW0lE  
2E7vuFH4c  
public FileAccessI(String sName,long nPos) throws IOException gkkT<hEV=  
{ -|_#6-9  
oSavedFile = new RandomAccessFile(sName,"rw"); "]H_;:{f  
this.nPos = nPos; %?  87#|  
oSavedFile.seek(nPos); `_"F7Czn  
} .l1uqCuB  
JO3"$s|t  
N(ov.l;  
public synchronized int write(byte[] b,int nStart,int nLen) [9N>*dKB  
{ T'C^,,if  
int n = -1; 'Z ;8-1M?O  
try{ :]]#X ~J  
oSavedFile.write(b,nStart,nLen); jgpSFb<9F  
n = nLen; 5 1&||.  
} olLVT<  
catch(IOException e) q%&JAX=  
{ ' tyblj C  
e.printStackTrace (); d-k`DJ!  
} q)N]*~  
~| CWy  
dbVMG-z8  
return n; |-+IF,j  
} 9pF@#A9p  
<?8 aM7W7  
z.d1>w  
} `_;sT8  
WZh%iuI{C  
L<dJWxf?D  
/* >G#SfE$0  
**SiteInfoBean.java WlJ=X$  
*/ r~2>_LK  
package NetFox; 'aV/\a:*  
o*5iHa(Qm  
yq7gBkS  
public class SiteInfoBean { ~(v7:?  
c2E*A+V#u  
B:X,vE  
private String sSiteURL; //Site's URL =5l20 Um  
private String sFilePath; //Saved File's Path _EEOBaZ  
private String sFileName; //Saved File's Name IJ[r!&PY  
private int nSplitter; //Count of Splited Downloading File |^:qJ;dOP  
3:]c>GPQ  
pHNo1-k\  
public SiteInfoBean() UA0j#  
{//nSplitter的缺省值为5 .Tm m  
//default value of nSplitter is 5 t@"i/@8x$  
this("","","",5); arWP]%E0W  
} $:l>g)c  
A.YXK%A%  
E&z`BPd  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Vf*Z}'  
{ @yImR+^.7  
sSiteURL= sURL; S&JsDPzSd  
sFilePath = sPath; ! )x2   
sFileName = sName; WgTD O3  
this.nSplitter = nSpiltter; od=x?uBVd  
dilom#2l  
<@4 48,9&  
} a]S0|\BkN  
ovXU +8  
*r90IS}A$2  
public String getSSiteURL() d94 Le/E  
{ .D8|_B  
return sSiteURL; Tf*DFyr  
} .91@T.  
1SK|4Am  
ybY[2g2QJ  
public void setSSiteURL(String value) _GbwyfA n#  
{ 3bN]2\   
sSiteURL = value; chC= $(5t  
} _uf,7R-  
Y W9+.Dc`  
hj4mbL  
public String getSFilePath() F $6JzF$|F  
{ je#OV,uHM  
return sFilePath; h<0&|s*a)  
} }mdk+IEt  
b0| ;v-v  
"h`oT4j5q  
public void setSFilePath(String value) :3N&&]  
{ Y n7z#bu  
sFilePath = value; YZdV0 -S  
} $*')Sma  
$o%:ST4  
zB68%  
public String getSFileName() )q|a Sd  
{ VFI\2n`  
return sFileName; ^:cc3wt'3[  
} I<+i87=  
EA``G8Vn>  
+bDBc?HZ{$  
public void setSFileName(String value) 8\VP)<<  
{ rNN ,!  
sFileName = value; 3YO %$  
} J\l'nqS"  
[k<.BCE  
e2_p7   
public int getNSplitter() DD fw& y  
{ ;.U<Lr^9#  
return nSplitter; {A`J0ol<B9  
} E (.~[-K4  
"$k rK7Z  
)&{<gyS1  
public void setNSplitter(int nCount) ,_M  
{ HD_ #-M  
nSplitter = nCount; : *8t,f~s^  
} J?%ecCN  
} w.o>G2u  
3j7Na#<tL3  
@#QaaR;4  
/* `e[>S  
**Utility.java 7R7e3p,K  
*/ 6>NK2} `  
package NetFox; ){I!orQ  
"$#<+H>O  
-T=sY/O  
public class Utility { {2.zzev'  
&V(;zy4(R  
#ZyY(S1.  
public Utility() 34F;mr"yp  
{ j"r7M|Z+V  
!nDiAjj  
q|ZzGEj:OV  
} J3QL%#  
i4}+n^oSYo  
//线程睡眠 2|A?9aE%0  
public static void sleep(int nSecond) k?;@5r)y-  
{ qYP;`L}o#  
try{ J{U 171  
Thread.sleep(nSecond); ]o?r( 1  
} f=hT o!i  
catch(Exception e) Y(&rlL(sPK  
{ eq(1'?7]`G  
e.printStackTrace (); uGpLh0  
} 8 RA  
} -2B3 xIZJ  
QV[#^1  
//日志 nrV!<nNBk  
public static void log(String sMsg) "F:V$,mJ  
{ Vji:,k=3\  
System.err.println(sMsg); |)*9BN  
} {,B. OM)J  
Wud-(19  
^{Fo,7  
public static void log(int sMsg) }2hU7YWt  
{ NjbIt=y  
System.err.println(sMsg); \GPTGi5A  
} l T#WM]  
} )kEH}P&  
{X10,  
3Z}v%=5 "  
/* Hxx]q+DAS  
**TestMethod.java \SN>Yy  
*/ \Mzr[dI  
package NetFox; N4l}5(e  
aTwBRm  
muMd9\p  
public class TestMethod { qVssw* GDB  
88KQ) NU  
Vg(FF "  
public TestMethod() .hRtQU  
{ ///xx/weblogic60b2_win.exe Dkg^B@5Xr  
try{ M%Zh{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A|( !\J0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `=lo.c  
SiteFileFetch fileFetch = new SiteFileFetch(bean); BtrMv6  
fileFetch.start(); @E4ya$A)F  
} Q`!^EyRA:^  
catch(Exception e){e.printStackTrace ();} ~t1?oJ  
DQ@M?~1hp  
2f6BZ8H+Z  
} BvS!P8  
NJCSo(O  
&2nICAN[  
public static void main(String[] args) L[^.pO  
{ D*/fY=gK  
new TestMethod(); g:s|D hE[  
} E/<n"'0ek  
} [!#}#  
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