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http断点续传简单实现(java)

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/* 9j#@p   
**SiteFileFetch.java O]qPmEj  
*/ /9_#U#vhY  
package NetFox; 2 B` 8eb  
import java.io.*; \r;F2C0*i  
import java.net.*; FH*RU1Z  
&fSTR-8ev#  
hYb9`0G"2  
public class SiteFileFetch extends Thread { C`4gsqD;Z  
d(S}NH  
10MU-h.)  
SiteInfoBean siteInfoBean = null; //文件信息Bean |sc Uo~  
long[] nStartPos; //开始位置 g.a| c\WH  
long[] nEndPos; //结束位置 % {Q-8w!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 RrWNJ&o  
long nFileLength; //文件长度 vg(K$o{BT  
boolean bFirst = true; //是否第一次取文件 JJ5C}`(  
boolean bStop = false; //停止标志 frqJN  
File tmpFile; //文件下载的临时信息 kCA5|u  
DataOutputStream output; //输出到文件的输出流 cNj*E =~;  
io4aYB\  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) D1Yh,P<CF\  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;+`uER  
{ e<5Y94YE  
siteInfoBean = bean; q# vlBL  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); bx>i6 R2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @!\K>G >9[  
if(tmpFile.exists ()) ]a/'6GbR  
{ 4;*f1_;f~  
bFirst = false; %-j&e44  
read_nPos(); CgnXr/!L  
} VXIQw' Cq  
else 8#59iQl  
{ d+}kg  
nStartPos = new long[bean.getNSplitter()]; (1){A8=?o  
nEndPos = new long[bean.getNSplitter()]; <xn;bp[  
} de YyaV  
aws"3O% uW  
Z;b+>2oL  
A}G|Yfn  
} -3hCiKq  
Q)^g3J  
ow.6!tl0=h  
public void run() x~/+RF XF  
{ onl>54M^  
//获得文件长度 g:gB`8w?  
//分割文件 ^\wl2  
//实例FileSplitterFetch ;&?pd"^<_Z  
//启动FileSplitterFetch线程 A/ 0qk  
//等待子线程返回 J_ J+cRwq  
try{ ?63&g{vA  
if(bFirst) \##`pa(8  
{ HomN/wKh  
nFileLength = getFileSize(); i&Kz*,pt  
if(nFileLength == -1) l`gTU?<xd  
{ ]}LGbv"`A  
System.err.println("File Length is not known!"); xjq0D[  
} 2P5_zND  
else if(nFileLength == -2) _e'Y3:  
{ K t `  
System.err.println("File is not access!"); 4P kfUMX  
} qtzRCA!9(Z  
else P(h5=0`*PR  
{ 2p:r`THvS5  
for(int i=0;i<nStartPos.length;i++) N5 n>  
{ /#t&~E_|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _P 5P(^/  
} 8A{6j  
for(int i=0;i<nEndPos.length-1;i++) 7X'y>\^w^>  
{ .ECHxDp  
nEndPos = nStartPos[i+1]; !R:y'Y%j  
} 2u:4$x8  
nEndPos[nEndPos.length-1] = nFileLength; -<W2PY<  
} m0( E kK  
} ,{{SI  
dr })-R  
$']VQ4tZ  
//启动子线程 40K2uT{cq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =n0*{~r  
for(int i=0;i<nStartPos.length;i++) -(;LQDG |  
{ /EFq#+6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  c8DZJSO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `ROEV~  
nStartPos,nEndPos,i); Dip*}8$o(w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WC-_+9)2&  
fileSplitterFetch.start(); n33kb/q*  
} U9ZbVjqv@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H_B~P%E@]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =!<G!^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", mG(N:n%*K  
nEndPos = " + nFileLength); kRot7-7I|  
// fileSplitterFetch[nPos.length-1].start(); +d39f-[  
:vQM>9l7  
0Nr\2|  
//等待子线程结束 WE.Tuo5L  
//int count = 0;  5$Kf]ZP  
//是否结束while循环 T *P+Fh"  
boolean breakWhile = false; _#'9kx|)  
oR %agvc^^  
JTUNb'#RZ  
while(!bStop) NWKi ()nA%  
{ :ba/W&-d  
write_nPos(); eXzXd*$S  
Utility.sleep(500); '_o@V O  
breakWhile = true; *not.2+  
V}9;eJRvw  
s4t0f_vj`  
for(int i=0;i<nStartPos.length;i++) E`AYee%l  
{ 3N< & u   
if(!fileSplitterFetch.bDownOver) }kPVtSQ  
{ ;CmOsA,1  
breakWhile = false; 4lz{G*u  
break; J{ ~Rxa  
} 9S1#Lr`r  
} hC>wFC  
if(breakWhile) - ]Y wl  
break; 6k9LxC:M  
UqtHxEI%R~  
/`+7_=-  
//count++; h4 vm{ho  
//if(count>4) ~:2K#q5C  
// siteStop(); 8:{ q8xZ=k  
} tWk{1IL  
zM59UQU;  
abWl ut  
System.err.println("文件下载结束!"); Sdc*rpH"(  
} Yx1 D)  
catch(Exception e){e.printStackTrace ();} `-O= >U5nH  
} 2R`u[  
?,% TU&Yn  
0Q1/n2V  
//获得文件长度 (=JueF@J  
public long getFileSize() ( u f5\}x  
{ kaFnw(xa  
int nFileLength = -1; 9#@Zz4Ww  
try{ IVteF*8hU  
URL url = new URL(siteInfoBean.getSSiteURL()); ,F: =(21  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (~#G'Hd  
httpConnection.setRequestProperty("User-Agent","NetFox"); }1m_o@{3P  
"{( [!  
( V4G<-jG  
int responseCode=httpConnection.getResponseCode(); O5-;I,)H  
if(responseCode>=400) (,LL[&;:  
{ 'F5)ACA%  
processErrorCode(responseCode);  :]c=pH  
return -2; //-2 represent access is error F<r4CHfh;  
} ;r!\-]5$  
0w3b~RJ  
0&$xX!]  
String sHeader; Gvn: c/m;  
=|0/Ynfe  
l0`'5>  
for(int i=1;;i++) Mi74Xl i  
{ QymD-A"P  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O71BM@2<  
//Utility.log(in.readLine()); s.y}U5Ty?P  
sHeader=httpConnection.getHeaderFieldKey(i); g1qi\axm  
if(sHeader!=null) 8]C1K Zs  
{ 7) 0q--B  
if(sHeader.equals("Content-Length")) 2U%qCfh6|  
{ b1=pO]3u  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); S=O$JP79  
break; Wz{%"o  
} !K\itOEP-  
} v3^t/[e~:  
else H[BYE  
break; C*G/_`?9  
} *Sb2w*c>  
} fuyl/bx}  
catch(IOException e){e.printStackTrace ();} KjYDFrR4  
catch(Exception e){e.printStackTrace ();} ,?y7 ,nb  
HRHrSf7  
D rTM$)  
Utility.log(nFileLength); c[{UI  
a: IwA9!L  
,n5a])Dg  
return nFileLength; gj;@?o0  
} wOcg4HlW  
)E`+BH  
':sTd^V  
//保存下载信息(文件指针位置) P)IjL&[  
private void write_nPos() b~as64  
{ ;[~^( . f  
try{ xBWx+My  
output = new DataOutputStream(new FileOutputStream(tmpFile)); UE7'B?  
output.writeInt(nStartPos.length); w `!LFHK  
for(int i=0;i<nStartPos.length;i++) `,Zb2"  
{ g)cY\`&W8  
// output.writeLong(nPos); } J(1V!EA  
output.writeLong(fileSplitterFetch.nStartPos); ]ymC3LV]  
output.writeLong(fileSplitterFetch.nEndPos); .K7C-Xn=  
} 6Ahr_{  
output.close(); 7TdQRB  
} 0||F`24  
catch(IOException e){e.printStackTrace ();} Ilef+V^qr  
catch(Exception e){e.printStackTrace ();} p`p?li  
} k<O y%+C  
%M6 c0d[9-  
C8MWIX}  
//读取保存的下载信息(文件指针位置) jGiw96,Y  
private void read_nPos() 4:`[qE3  
{ raHVkE{<  
try{ 2Oi'E  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); % $.vOFP9  
int nCount = input.readInt(); $_bZA;EMQ  
nStartPos = new long[nCount]; $rTu6(i1  
nEndPos = new long[nCount]; DZP*x  
for(int i=0;i<nStartPos.length;i++) GBr,LN  
{ -t>Z 9  
nStartPos = input.readLong(); )JX$/- RD-  
nEndPos = input.readLong(); hr1$1&p  
} .qinR 6=  
input.close(); 9A<0zt  
} mt^`1ekoY  
catch(IOException e){e.printStackTrace ();} \!4|tBKVY  
catch(Exception e){e.printStackTrace ();} cD8Ea(  
} @T/qd>T o  
GEfY^! F+  
U2UyN9:6F  
private void processErrorCode(int nErrorCode) -p^'XL*Z  
{ P'F~\**5  
System.err.println("Error Code : " + nErrorCode); g8v[)o(qd  
} P4[]qbfd,  
`:gYXeR  
yU!GS-  
//停止文件下载 {\Ys@FF  
public void siteStop() @E(P9zQ/zy  
{ V" }*"P-%  
bStop = true; 6lZGcRO  
for(int i=0;i<nStartPos.length;i++) }Az'Zu4 =  
fileSplitterFetch.splitterStop();  z \^  
Se/ss!If  
N-Z^G<[q.  
} ,\}k~ U99  
} ()B7(Y  
//负责部分文件的抓取 ) H+d.Y  
**FileSplitterFetch.java ETg{yBsp  
*/ HSC6;~U  
package NetFox; Tplg2p% k  
Oc~VHT  
H\d;QN9Q;  
import java.io.*; kw#X]`c3  
import java.net.*; AbG&9=Ks  
D@*|24y  
[tz u;/  
public class FileSplitterFetch extends Thread { u ]SZ{[ e  
90(UgK&Y  
V:8@)Hc=  
String sURL; //File URL jf8w7T  
long nStartPos; //File Snippet Start Position kAt RY4p  
long nEndPos; //File Snippet End Position GqMB^Ad  
int nThreadID; //Thread's ID L^x5&CCwk  
boolean bDownOver = false; //Downing is over FXxN>\76.  
boolean bStop = false; //Stop identical UtPwWB_YV  
FileAccessI fileAccessI = null; //File Access interface L, #Byao  
S<9gyW  
hWm0$v 1p  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $i -zMa  
{ df yrn%^Ia  
this.sURL = sURL; #XfT1  
this.nStartPos = nStart; Yq{jEatY{/  
this.nEndPos = nEnd; &rcdr+'  
nThreadID = id; s4N,^_j  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 xlk5Gob*  
} ;8uHRcdQ  
E;$$+rA  
]y}Zi/zh  
public void run() :k\} I k  
{ r;$r=Ufr  
while(nStartPos < nEndPos && !bStop) /0-\ek ye  
{ }\ EL;sT  
lZBv\JE  
Gg}t-_M  
try{ xmOM<0T  
URL url = new URL(sURL); 1j+eD:d'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \:h0w;34O  
httpConnection.setRequestProperty("User-Agent","NetFox"); Eh:yR J_8  
String sProperty = "bytes="+nStartPos+"-"; :Nkz,R?  
httpConnection.setRequestProperty("RANGE",sProperty); &D^e<j}RQ  
Utility.log(sProperty); 8a?IC|~Pz  
i"< ZVw  
Pm~,Ky&Hl  
InputStream input = httpConnection.getInputStream(); `{Hb2 }L5  
//logResponseHead(httpConnection); C!hXEtK  
d;<.;Od$`  
$.;iu2iyo  
byte[] b = new byte[1024]; K(' 9l& A  
int nRead; vWuyft*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'Z y{mq\  
{ ~RAzFLt6x  
nStartPos += fileAccessI.write(b,0,nRead); $Q=$?>4U  
//if(nThreadID == 1) :ET x*c  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8pd&3G+  
} k~& o  
v,8Si'"i+  
kF#{An)P  
Utility.log("Thread " + nThreadID + " is over!"); M*v^N]>"G  
bDownOver = true; y _6r/z^  
//nPos = fileAccessI.write (b,0,nRead); 9Il'E6 J  
} =#jTo|~u4o  
catch(Exception e){e.printStackTrace ();} [+_\z',u  
} } mgVC  
} aE}=^%D  
\;i G{}(  
KLON;  
//打印回应的头信息 Z`|>tbOfZ  
public void logResponseHead(HttpURLConnection con) 2UQN*_  
{ ,=yOek}  
for(int i=1;;i++) W%=Zdm rv  
{ 3F;EE:  
String header=con.getHeaderFieldKey(i); [1e.i  
if(header!=null) $x/J+9Ww  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 3Sk5I%  
Utility.log(header+" : "+con.getHeaderField(header)); EkDws `@  
else GpScc'a7  
break; wE)] ah:  
} )7tV*=?Ic8  
} e<kpcF5{\  
Xad G\_?t`  
.[#xQ=9`  
public void splitterStop() K6ciqwUO  
{ YcPKM@xo  
bStop = true; \m@] G3=]  
} /FoUo   
D\@e{.$MZ|  
$# D n4  
} cn@03&dAl  
c]S+70!n  
U<K|jsFo  
/* *Rz!i m|  
**FileAccess.java jQO* oq}  
*//文件访问(定位,写) 0kkRK*fp}x  
package NetFox; '9f6ZAnYpQ  
import java.io.*; 7sCR!0  
o7m99(  
l# }As.o}  
public class FileAccessI implements Serializable{ :P HUsy  
`^?}s-H+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 nZ"{y  
RandomAccessFile oSavedFile; y?[5jL|Ue  
long nPos; pM1=U F  
od;Bb  
d&O'r[S  
public FileAccessI() throws IOException #( $k 3OA  
{ oXnC "y}0P  
this("",0); 5w]DncdQ~  
} &19l k   
LZgwIMd  
y>DfM5>  
public FileAccessI(String sName,long nPos) throws IOException l~`txe  
{ K(%dcUGDK>  
oSavedFile = new RandomAccessFile(sName,"rw"); 4x=V|"  
this.nPos = nPos; Pn~pej5'K  
oSavedFile.seek(nPos); 8XLxT(YFIs  
} Y:DNu9  
.CIbpV?T  
3L'en  
public synchronized int write(byte[] b,int nStart,int nLen) >lUBt5gU  
{ n$XMsl.>  
int n = -1; 1EKcD^U,  
try{ aeN }hG  
oSavedFile.write(b,nStart,nLen); 9:bh3@r/  
n = nLen; nF|#@O`1  
} #j(q/ T{x  
catch(IOException e) tI/mE[W  
{ x.jYip  
e.printStackTrace (); K0d-MC   
} s :-8 Z\,  
<B|n<R<?  
Z!q2F%02FO  
return n; IKNFYe[9e  
} Jnh;;<  
=;~%L  
z ^gDbXS  
} Dme(Knly  
Co{MIuL  
Xq=!"E  
/* z&>9 s)^-  
**SiteInfoBean.java B:R7[G;1  
*/ _ Yb Eo+  
package NetFox; #u}v7{4  
.0 R/'!e  
9,Crmbw8  
public class SiteInfoBean { @lb=-oR!~  
pgLzFY['  
>S?C {_g  
private String sSiteURL; //Site's URL PCV58n3  
private String sFilePath; //Saved File's Path 8GF[)z&|P:  
private String sFileName; //Saved File's Name 3B!&ow<rt  
private int nSplitter; //Count of Splited Downloading File UUdu;3E=5  
$sd3h\P&R  
];d5X  
public SiteInfoBean() i_oro "%yL  
{//nSplitter的缺省值为5 ;-Y]X(z>  
//default value of nSplitter is 5 mh!N^[=n  
this("","","",5); g:~?U*f-  
} ?~]1Gd  
.N-'; %8  
nzQYn  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |k['wqn"  
{ YoSo0fQA  
sSiteURL= sURL; !Vp,YN+yN  
sFilePath = sPath; ^C,/T2>  
sFileName = sName; [0**&.obz  
this.nSplitter = nSpiltter; _D7HQ  
H3UX{|[  
o2 T/IJP  
} 7Ap~7)z[  
XNkQk0i;g&  
vV:M S O'r  
public String getSSiteURL() WwCK  K  
{ LX(iuf+l  
return sSiteURL; 4z-,M7iP  
} 8JjU 9#  
^t/'dfF  
`a/PIc"  
public void setSSiteURL(String value) 1drqWI~  
{ WIH4Aw  
sSiteURL = value; fY,@2VxyfA  
} OI]K_ m3  
IgHs&=  
61s2bt#  
public String getSFilePath() ZH`K%h0  
{ *`S)@'@:(  
return sFilePath; rlUdAa3  
} K[Egwk7  
buC m @@o  
5m%baf2_  
public void setSFilePath(String value) alb+R$s  
{ ]"2 v7)e  
sFilePath = value; 3-_U-:2"  
} <L!~f`nH2  
U4^p({\|-  
]U^d1&k  
public String getSFileName() \^;|S  
{ Dbkuh!R  
return sFileName; sBuq  
} SG+i\yu$h0  
q. ,p6D  
\/x)BE,  
public void setSFileName(String value) 6ljRV)  
{ ELkOrV~a{:  
sFileName = value; 0]2B-o"kI  
} HhY2`P8  
;f ;*Q>!  
28UL  
public int getNSplitter() xP5mL3j  
{ ;+TF3av0zq  
return nSplitter; J?n)FgxS  
} [-:<z?(n4  
&\6`[# bT  
} {gWTp  
public void setNSplitter(int nCount) 3>@qQ_8%~  
{ _?(hWC"0  
nSplitter = nCount; }Nd`;d  
} >m_ p\$_  
} ;SlS!6.W-  
jN'fm  
t\|K"  
/* asmW W8lz  
**Utility.java abJ@>7V  
*/ 3qxG?G N  
package NetFox; jFPE>F7-M  
F)<G]i8n~  
h2/1S{/n]  
public class Utility { hOrk^iYN=  
+ k(3+b$S-  
9^ *ZH1  
public Utility() ~a8G 5M  
{ 5S-o 2a  
Pguyf2/w  
ixJ20A7  
} +v[$lh+  
Oz9Mqcx  
//线程睡眠 eI=Y~jy  
public static void sleep(int nSecond) ?C>VB+X}y  
{ m^oi4mV  
try{ n.8A Ka6  
Thread.sleep(nSecond); T>uWf#&pjs  
} Uc4 L|:  
catch(Exception e) @IyH(J],h  
{ }^ Ua  
e.printStackTrace (); <{z3p:\  
} !Bd* L~D  
} CXP $bt}  
Q3'B$,3O^  
//日志 M;TfD  
public static void log(String sMsg) "JUQ)> !?  
{ tm36Lw  
System.err.println(sMsg); !K^Z5A_;  
} s*~jvL  
:Z]+Z_9p  
)zLS,/pk^  
public static void log(int sMsg) f w>Gx9  
{ M_.,c Vk  
System.err.println(sMsg); }$k`[ivBx(  
} eze(>0\f  
} ]R0A{+]n  
t1{%FJ0F  
Qpv}N*v^  
/* f$S QhK5`  
**TestMethod.java W!4V: (T  
*/ W.6 JnYLQ&  
package NetFox; >~wk  
3f2Hjk7,d  
Z"%O&O  
public class TestMethod { ; R|#ae@  
~ :b:_ 5"  
$8T|r+<  
public TestMethod() r dG2| Tp  
{ ///xx/weblogic60b2_win.exe <iprPk  
try{ D15u1A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _d=&9d#=\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ://# %SE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]E8<;t)#  
fileFetch.start(); 6RT0\^X*:  
} >\oJ&gdc  
catch(Exception e){e.printStackTrace ();} I&NpN~AU  
!%\To(r[  
$Ex 9  
} zf;[nz  
ONe!'a0  
`0G.Y  
public static void main(String[] args) [Fj#7VZK  
{ >8fz ?A  
new TestMethod(); L9YwOSb.  
} k| cI!   
} 3(GrDO9^  
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