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http断点续传简单实现(java)

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/* eV7 u*d?  
**SiteFileFetch.java ^"i~ DC  
*/ wX,F`e3"/  
package NetFox; ;%Hf)F  
import java.io.*; ?La Ued'  
import java.net.*; G7@ O`N8'  
&:5\"b  
tX%`#hb?s  
public class SiteFileFetch extends Thread { rwE%G>Vb  
=IjQ40W  
ROc`BH=  
SiteInfoBean siteInfoBean = null; //文件信息Bean -#s [F S  
long[] nStartPos; //开始位置 j_cs;G: "  
long[] nEndPos; //结束位置 cz/Q/%j$/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 z[EFQ^*>  
long nFileLength; //文件长度 jrMe G.e=D  
boolean bFirst = true; //是否第一次取文件 :+rUBYWx  
boolean bStop = false; //停止标志 g(ogXA1  
File tmpFile; //文件下载的临时信息 3c3OG.H$8  
DataOutputStream output; //输出到文件的输出流 wJ+Aw  
Ysi  g T  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) -JT/ 9IQ  
public SiteFileFetch(SiteInfoBean bean) throws IOException 'h1b1,b~  
{ T=Z.TG|lIx  
siteInfoBean = bean; mQ~:Y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W# US#<9Y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Te,$M3|  
if(tmpFile.exists ()) b)# Oc,  
{ ;GGK`V  
bFirst = false; ^U[D4UM  
read_nPos(); :dI\z]Y(  
} MXD4|r(  
else @b#^ -  
{ k1 -~  
nStartPos = new long[bean.getNSplitter()]; t*XN_=E$f  
nEndPos = new long[bean.getNSplitter()]; FFKGd/:!  
} PVOx`<ng  
3)=c]@N0  
u3 0s_\  
[ ho (z30k  
} xiblPF_n3  
.dMVoG5  
:9t4s#.  
public void run() ?.=}pAub  
{ qJ4T]FVN  
//获得文件长度 r|Z5Xc  
//分割文件 O$u"/cwe*  
//实例FileSplitterFetch J%H;%ROx  
//启动FileSplitterFetch线程 _+l1 b"^s1  
//等待子线程返回 p[AO' xx  
try{ rQ`i8GF  
if(bFirst) l^MzN  
{ LwcIGhy  
nFileLength = getFileSize(); GB7/x*u   
if(nFileLength == -1) Q]/Uq~m C  
{ cD|Htt"  
System.err.println("File Length is not known!"); M<PIeKIEB  
} X0(tboj#  
else if(nFileLength == -2) =ONHK F[UJ  
{ ^5GW$  
System.err.println("File is not access!"); 7R4z}2F2  
} mEyK1h1G @  
else 4QOEw-~w&s  
{ ikD1N  
for(int i=0;i<nStartPos.length;i++) [BBEEI=|r  
{ T:]L/wCj  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); BQH}6ueZ  
} F[ ajOb8  
for(int i=0;i<nEndPos.length-1;i++) =3ioQZ^Vz  
{ _5 ^I.5Z3  
nEndPos = nStartPos[i+1]; %V9ZyQg%*  
} <_Z:'~Zp  
nEndPos[nEndPos.length-1] = nFileLength; 7Z ;?b0W  
} ^O(=Vry  
} {--0 z3n>  
U6E\AvbRn  
a, Q#Dk  
//启动子线程 ZK;zm  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fA/m1bYxg  
for(int i=0;i<nStartPos.length;i++) (Rt7%{*  
{ mm[2wfTE  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %p^.|Me7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 'H5M|c$s  
nStartPos,nEndPos,i); GeszgtK{T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2d%}- nw  
fileSplitterFetch.start(); k3?rp`V1  
} ;W>Cqg=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RlT3Iz;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ML;*e"$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", OU5*9_7.  
nEndPos = " + nFileLength); ,)PiP/3B  
// fileSplitterFetch[nPos.length-1].start(); jHN +5=l  
-HSs^dP`  
O$/o'"@ /  
//等待子线程结束 r(d':LV  
//int count = 0; 5DOBs f8Jo  
//是否结束while循环 y[B>~m8$  
boolean breakWhile = false; HK\~Qnq  
~'37`)]z  
\`V;z~@iA  
while(!bStop) # mize  
{ H]4Hj  
write_nPos(); KL$bqgc(p3  
Utility.sleep(500); ^7zu<lX  
breakWhile = true; .#02 ngh  
['8!qr  
_@S`5;4x  
for(int i=0;i<nStartPos.length;i++) xGTP;NT_H  
{ ljl^ GFo  
if(!fileSplitterFetch.bDownOver) `.s({/|[  
{ z'T) =ycT  
breakWhile = false; V%$/#sza  
break; v8AS=sY4r  
} .920{G?l5  
} bR@p<;G|  
if(breakWhile) ]smkTo/  
break; qC F5~;7  
][}0#'/mV  
{*{Ox[Nh{  
//count++; Eu"_MgD  
//if(count>4) 'y8]_K*  
// siteStop(); L "sO+4w  
} )95f*wte  
p<=$&*  
{(r6e  
System.err.println("文件下载结束!"); *CHI2MB  
} dy_:-2S  
catch(Exception e){e.printStackTrace ();} =zQN[  
} ;WR,eI..  
Ft}@ 1w5  
9tF9T\jW  
//获得文件长度 #o1=:PQaC  
public long getFileSize()  : ]C~gc  
{ (#+^&1  
int nFileLength = -1; TB0 5?F  
try{ !K|5bK  
URL url = new URL(siteInfoBean.getSSiteURL()); mI74x3 [  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SlsdqP 9  
httpConnection.setRequestProperty("User-Agent","NetFox"); oudxm[/U  
lNSLs"x^  
,VO2a mI  
int responseCode=httpConnection.getResponseCode(); 8WnwQ%;m?  
if(responseCode>=400) |sJSN.8  
{ E>l~-PaZY  
processErrorCode(responseCode); sQkhwMg  
return -2; //-2 represent access is error oJN#C%r7  
} 7uzk p&+:  
kc0E%odF.v  
|i++0BU  
String sHeader; Ub6jxib  
0_88V  
(o`{uj{!  
for(int i=1;;i++) A~-b!Grf  
{ 2}8v(%s p  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |\pbir  
//Utility.log(in.readLine()); oq}'}`lw"  
sHeader=httpConnection.getHeaderFieldKey(i); !qG7V:6  
if(sHeader!=null) $|8!BOx8t  
{ Jv^h\~*jH  
if(sHeader.equals("Content-Length")) O%bEB g  
{ vN;mP d~g  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); EFz&N\2  
break; eA<0$Gs,h  
} !KUi\yQ1  
} #\=FO>  
else % >=!p  
break; B {>7-0  
} ZHa"isl$e  
} u?C#4  
catch(IOException e){e.printStackTrace ();} wb0L.'jyR)  
catch(Exception e){e.printStackTrace ();} WlU0:(d  
VVlr*`  
z4N*b"QF  
Utility.log(nFileLength); wpN=,&!  
q@{Bt{$x  
GWfL  
return nFileLength; LGn:c;  
} }4,L%$@n  
'dn]rV0(C  
!z>6 Uf!{  
//保存下载信息(文件指针位置) 2'w?\{}D  
private void write_nPos() ~sh`r{0  
{ ?32&]iM oW  
try{ }~L.qG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); E 7{U |\  
output.writeInt(nStartPos.length);  qi^7  
for(int i=0;i<nStartPos.length;i++) ~A\GT$  
{ 9iQq.$A.  
// output.writeLong(nPos); F%RRd/'  
output.writeLong(fileSplitterFetch.nStartPos); |!4K!_y  
output.writeLong(fileSplitterFetch.nEndPos); 1eF3`  
} .6Pw|xu`Pw  
output.close(); 5?x>9C a  
} wfH^<jY)E  
catch(IOException e){e.printStackTrace ();} r8RoE`/T  
catch(Exception e){e.printStackTrace ();} Tc? $>'  
} %$.3V#?  
K|[*t~59  
NPp;78O0[  
//读取保存的下载信息(文件指针位置) 'd9INz.  
private void read_nPos() %#kg#@z_`e  
{ a!v1M2>  
try{ t7aefV&_,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :/nj@X6  
int nCount = input.readInt(); cPlZXf  
nStartPos = new long[nCount]; H*PSR  
nEndPos = new long[nCount]; ;{N!Eb`S  
for(int i=0;i<nStartPos.length;i++) fumm<:<CLO  
{ U2W|:~KM  
nStartPos = input.readLong(); yd d7I&$  
nEndPos = input.readLong(); \XZ/v*d0  
} "~|6tQLc  
input.close(); gi1^3R[  
} .[ICx  
catch(IOException e){e.printStackTrace ();} RMdk:YvBg  
catch(Exception e){e.printStackTrace ();} Hquc o  
} `r9!zffyS  
Hx?;fl'G%  
X aMJDa|M  
private void processErrorCode(int nErrorCode) 3`DQo%<  
{ g,!L$,/F  
System.err.println("Error Code : " + nErrorCode); b gK}-EU  
} u7>],<  
yPb"V  
!$gR{XH$]  
//停止文件下载 GjvOM y  
public void siteStop() N 5lDS  
{ 3YR!Mq$|~  
bStop = true; 0AL=S$B)  
for(int i=0;i<nStartPos.length;i++) p8Qk 'F=h  
fileSplitterFetch.splitterStop(); |v 3T!  
vdc\R?  
gCB |DY  
} @niHl  
} Swig;`  
//负责部分文件的抓取 s"r*YlSp"  
**FileSplitterFetch.java vApIHI?-  
*/ G[uK-U  
package NetFox; (x;@%:3j$  
nFHUy9q  
"R;U/+  
import java.io.*; 8;RUf~q?  
import java.net.*; K0|FY=#2y  
W}@c|d $`  
aC8} d  
public class FileSplitterFetch extends Thread { C)ERUH2i  
0z6R'Kjy A  
KQ% GIz x  
String sURL; //File URL 8Fz#A.%P  
long nStartPos; //File Snippet Start Position z]_wjYn Z  
long nEndPos; //File Snippet End Position {EB;h\C  
int nThreadID; //Thread's ID vc;$-v$&  
boolean bDownOver = false; //Downing is over *v!9MU9[(  
boolean bStop = false; //Stop identical Z&+ g;(g  
FileAccessI fileAccessI = null; //File Access interface 1Y\DJ@lh  
6*78cg Io  
2lH&  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =(j1rW!  
{ X9W@&zQ  
this.sURL = sURL; un mJbY;t  
this.nStartPos = nStart; hd%F nykq  
this.nEndPos = nEnd; l *(8i ^  
nThreadID = id; &N^9JxN?8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BU/"rv"(Fg  
} [Kg+^N% +  
99e.n0  
;#W2|'HD  
public void run() 2j [=\K]  
{ c<:-T  
while(nStartPos < nEndPos && !bStop) ~ D j8 z+^  
{ l`lk-nb  
].w4$OJ?  
M6 "PX *K  
try{ !GjQPAW  
URL url = new URL(sURL); iy.p n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BO?%'\  
httpConnection.setRequestProperty("User-Agent","NetFox"); zZPO&akB"  
String sProperty = "bytes="+nStartPos+"-"; nV|EQs4(  
httpConnection.setRequestProperty("RANGE",sProperty); mp1@|*Sn  
Utility.log(sProperty); Uiw2oi&_  
3wF;GG  
nfbR P t  
InputStream input = httpConnection.getInputStream(); l ^0@86  
//logResponseHead(httpConnection); @Md/Q~>  
hR?{3d#x2  
Mq156TL  
byte[] b = new byte[1024]; hn G Z=  
int nRead; e'NJnPO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) me$Z~/Akm  
{ AlaW=leTe  
nStartPos += fileAccessI.write(b,0,nRead); 5{X<y#vAC0  
//if(nThreadID == 1) {UI+$/v#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y%cP1y)  
} hED}h![  
z\W64^'"Z  
,]F,Uu_H7  
Utility.log("Thread " + nThreadID + " is over!"); -l*|M(N\  
bDownOver = true; &jJL"gq"  
//nPos = fileAccessI.write (b,0,nRead); \;B iq`  
} y'q$ |  
catch(Exception e){e.printStackTrace ();} AO4U}?  
} ,?%Zc$\LW  
} b4 6~?*  
+Mb.:_7'  
Rh{f5-  
//打印回应的头信息 eF$x1|  
public void logResponseHead(HttpURLConnection con) JGrWHIsNV  
{ %$Tji  
for(int i=1;;i++) m=:9+z  
{ x=P\qjSa  
String header=con.getHeaderFieldKey(i); By!o3}~g  
if(header!=null) m+[Ux{$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); c7k~S-nU  
Utility.log(header+" : "+con.getHeaderField(header)); H/ HMm{4  
else Ax7[;|2  
break; lTgjq:mn  
} IM'r8 V  
} K;G~V\  
p8O2Z? \  
:P~6~ K um  
public void splitterStop() x|Bf-kc[#Q  
{ 1.GQau~  
bStop = true; O,f?YJ9S  
} <iC(`J$D  
j</: WRA`]  
g*_&  
} T.BW H2gRP  
A?P_DA  
6%_nZvRv  
/* UB@+c k  
**FileAccess.java K+3=tk]W9u  
*//文件访问(定位,写) +I|vzz`ZVr  
package NetFox; KkbDW3-  
import java.io.*; 7Ovi{xd@  
hL{KRRf>  
"ze|W\Bv!  
public class FileAccessI implements Serializable{ .Yn_*L+4*  
db7B^|Di  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 g8% &RG  
RandomAccessFile oSavedFile; #q=Efn'  
long nPos; 583|blL  
'-~~-}= sJ  
dUZ ,m9u  
public FileAccessI() throws IOException ;4|15S  
{ <\^8fn   
this("",0); }Zn}  
} aX'*pK/-  
sDlO#  
aEeodA<(  
public FileAccessI(String sName,long nPos) throws IOException Z@!+v 19^  
{ mz0X3  
oSavedFile = new RandomAccessFile(sName,"rw"); hRhe& ,v  
this.nPos = nPos; YNF k  
oSavedFile.seek(nPos); <PH #[dH  
} htF] W|z  
`M8i92V\qY  
^u ~Q/ 4  
public synchronized int write(byte[] b,int nStart,int nLen) "+G8d' %YV  
{ 9WyhZoPD*  
int n = -1; W^l-Y %a/o  
try{ &Ok):`  
oSavedFile.write(b,nStart,nLen); oap4rHk}  
n = nLen; `d}2O%P  
} S.NPZ39}ZE  
catch(IOException e) /*mI<[xb  
{ /h3RmUy   
e.printStackTrace (); h S&R(m  
} + cN8Y}V  
.aQ \jA  
1mG-}  
return n; 2P0*NQ   
} s;Q!X ?Q  
@\#td5'  
tG a8W  
} Gyc]?m   
(f"4,b^]  
yY q,*<G  
/* [{,1=AB  
**SiteInfoBean.java `[ir}+S  
*/ CLRdm ^B  
package NetFox; $ddCTS^  
q(84+{>B  
Y$@?.)tY  
public class SiteInfoBean { Lp9E:D->  
oCz/HQoBk  
<RL]  
private String sSiteURL; //Site's URL (9dl(QSd  
private String sFilePath; //Saved File's Path DB,J3bm  
private String sFileName; //Saved File's Name zTU0HR3A  
private int nSplitter; //Count of Splited Downloading File Y76gJ[y jn  
H4+i.*T#  
ep{FpB  
public SiteInfoBean() ]h5tgi?_l  
{//nSplitter的缺省值为5 eJ-nKkg~a  
//default value of nSplitter is 5 C,4e"yynb  
this("","","",5); fz "Y CHe  
} 61U09s%\0  
.Z *'d  
N;`n@9BF  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) S?2>Er  
{ =T7.~W  
sSiteURL= sURL; Y.p;1"  
sFilePath = sPath; oEpFuWp%A  
sFileName = sName; VI *$em O0  
this.nSplitter = nSpiltter; GZIa 4A  
}O p; g^W  
u>vL/nI  
} (#c:b  
Xsa].  
3!_XEN[  
public String getSSiteURL() & 1f+,  
{ jnwu9PQ  
return sSiteURL; 1?l1:}^L  
} u=e{]Ax#}  
N8df8=.kw  
$[ *w"iQ  
public void setSSiteURL(String value) ,I;> aE<#  
{ ;!Fn1|)  
sSiteURL = value; ,eS)e+yzc2  
} k+*u/neh  
x]j W<A  
%8v\FS  
public String getSFilePath() 1< ?4\?j  
{ S3J^,*'  
return sFilePath; n+M<\  
} 6ik$B   
, W?VhO  
.T`%tJ-Em  
public void setSFilePath(String value) E2-\]?\F(  
{ 1_G^w qk  
sFilePath = value; ) )Za&S*<  
} :g/tZd$G5  
uPvEwq* C  
{oL>1h,%3?  
public String getSFileName() 1|:KQl2q  
{ ;hq\  
return sFileName; Q/Rqa5LI:  
} {n=|Db~S  
#<xm.  
6aj!Q*(WT  
public void setSFileName(String value) -yg7;ff  
{ `WS&rmq&'  
sFileName = value; "<gOzXpa  
} N2o7%gJw  
-Lg Ei3m  
f6p/5]=J26  
public int getNSplitter() m4Zk\,1m.|  
{ -nwypu  
return nSplitter; %"-5 <6d  
} %z$#6?OK^  
!()Qm,1u  
5mR 1@  
public void setNSplitter(int nCount) J .<F"r>  
{ 1\.pMHv/  
nSplitter = nCount; ?V=CB,^  
} Iu6   
} W%w~ah|/]  
0*v2y*2V  
Gq P5Kx+=  
/* $:^td/p J  
**Utility.java Ho]su?  
*/ ;AG()NjOO:  
package NetFox; 19] E 5'AI  
W@esITr  
+w~oH=  
public class Utility { Uw:"n]G]D?  
d_P` qA  
hqdDm  
public Utility() $pz/?>!  
{ +cRn%ioVi  
[N'h%1]\  
t#yuOUg  
} 3(UVg!t  
V VCZ9MVJ  
//线程睡眠 uw8f ~:LT  
public static void sleep(int nSecond) !`r$"}g  
{ )M^ gT}M  
try{ ]_$[8#kg  
Thread.sleep(nSecond); p]"4#q\(  
} &e3.:[~_?  
catch(Exception e) & nK<:^n  
{ qJw_  
e.printStackTrace (); y_[vr:s5pG  
} ")25 qZae  
} S|}L&A  
 AOx[  
//日志 " Yy n/  
public static void log(String sMsg) t`QENXA}  
{ Xnh8e  
System.err.println(sMsg); TsZ@  
} i@'dH3-kO  
S]{oPc[7  
K> e7pu  
public static void log(int sMsg) >R=|Wo`Ri  
{ FiU#T.`9'  
System.err.println(sMsg); 3 gf1ownC  
} |f##5fB  
} FgO)DQm  
A2Tw<&Tw(  
,u!sjx  
/* B/C,.?Or  
**TestMethod.java -K$)DvV^(E  
*/ wA.\i  
package NetFox; :@&/kyGH  
y?# Loe  
dqAw5[qMJ  
public class TestMethod { +/\6=).\  
B erwI 7!=  
l;V173W=&  
public TestMethod() tMe~vq[  
{ ///xx/weblogic60b2_win.exe QSj]ZA  
try{ 1 {)Q[#l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %>s |j'{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); p 4)Q&k!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wNX]7wMX  
fileFetch.start(); ?%kV?eu'  
} |7Kbpj  
catch(Exception e){e.printStackTrace ();}  S[QrS 7  
I 2DpRMy  
J8~haim  
} 9>$p  
-Qe Z#w|  
A\;U3Zu  
public static void main(String[] args) We z 5N  
{ O'~+_ykTl  
new TestMethod(); hzC>~Ub5  
} PRT +mT  
} {:W$LWET  
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