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http断点续传简单实现(java)

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/* BA|*V[HBE  
**SiteFileFetch.java uSK<{UT~3  
*/ |#-GH$.v  
package NetFox; C\p _  
import java.io.*; }z8HS< #Q  
import java.net.*; eLAhfG  
~eHu +pv  
Se %"C&  
public class SiteFileFetch extends Thread { ZtqN8$[6n  
^{Y9!R*9U*  
0|_d{/VK4  
SiteInfoBean siteInfoBean = null; //文件信息Bean >R}p*=J  
long[] nStartPos; //开始位置 ;p'Ej'E  
long[] nEndPos; //结束位置 %{M&"Mv  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]pP [0 S  
long nFileLength; //文件长度 yjxv D  
boolean bFirst = true; //是否第一次取文件 96 !e:TU  
boolean bStop = false; //停止标志 RP4P"m(   
File tmpFile; //文件下载的临时信息 lGtTZ cg  
DataOutputStream output; //输出到文件的输出流 " )_-L8  
[boB4>.  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) kI>PaZ`i)  
public SiteFileFetch(SiteInfoBean bean) throws IOException ThSB\  
{ YE\s<$  
siteInfoBean = bean; |*WE@L5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); IQ"9#{o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !o&b:7  
if(tmpFile.exists ()) $'>h7].  
{ "FT(U{^7d  
bFirst = false; Z6xM(*vg  
read_nPos(); APBe 76'3)  
} 2k$~Mv@L  
else r*t\\2  
{ BTu_$5F  
nStartPos = new long[bean.getNSplitter()]; <i!7f26r  
nEndPos = new long[bean.getNSplitter()]; CA{(x(W\:  
} COf>H0^%Q  
.IJgkP)!]  
x#_0 6  
s5'So@L8  
} 6:vdo~  
Xm! ;  
WMLsKoby  
public void run() xK3}z N$T  
{ 2{E"#}/  
//获得文件长度 z(&~O;;N#  
//分割文件 I,xV&j+<  
//实例FileSplitterFetch 2E":6:Wsw  
//启动FileSplitterFetch线程 m@){@i2.  
//等待子线程返回 <ny)yK  
try{ eDPmUlC+-  
if(bFirst) Gv3AJ'NL  
{ +kK6G#c  
nFileLength = getFileSize(); A(Ss:7({  
if(nFileLength == -1) _7LZ\V+MLW  
{ 1Xi.OGl  
System.err.println("File Length is not known!"); Hs~u&c  
} NXw$PM|+R  
else if(nFileLength == -2) g$jZpU  
{ E}WO?xxv74  
System.err.println("File is not access!"); $m-rn'Q  
} h!L6NS_Q,  
else zU)Ib<$  
{ 4D-4BxN*  
for(int i=0;i<nStartPos.length;i++) }}'0r2S  
{ V]$Tbxg  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (NBq!;_2,x  
} ?yq1\G)]  
for(int i=0;i<nEndPos.length-1;i++) "2'pS<|  
{ +/E yX =  
nEndPos = nStartPos[i+1]; F};G&  
} =,-&h V  
nEndPos[nEndPos.length-1] = nFileLength; ]wQ#8}zO  
} BL^8gtdn  
} Z `)}1|~B  
M[@=m[#a  
AGdFJ>/  
//启动子线程 ,y5 7tY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jw"]U jub  
for(int i=0;i<nStartPos.length;i++) 3 O)^Hq+9  
{ nBA0LIb  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?{ 0MF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {yPiBu  
nStartPos,nEndPos,i); /=bg(?nX  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); CI )89`  
fileSplitterFetch.start(); k7gm)}RKcu  
} DJmT]Q]o)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0cwb^ffN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); e5 ?;{H  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", TEK]$%2  
nEndPos = " + nFileLength); eaxp(VX?oy  
// fileSplitterFetch[nPos.length-1].start(); [*k25N  
Iw<: k  
dk^Uf84.Gr  
//等待子线程结束 kCu"G  
//int count = 0; ~X`_ g/5X  
//是否结束while循环 };:+0k/  
boolean breakWhile = false; MZ{gU>K+  
_8U 5mW  
u,R;=DNl  
while(!bStop) z[I3k  
{ `;9Z?]}`  
write_nPos(); 1%nE  
Utility.sleep(500); FesXY856E  
breakWhile = true; [Ie;Jd>gG  
}op0`-Xb  
K; +w'/{  
for(int i=0;i<nStartPos.length;i++) Ae0jfTv  
{ fgW>U*.ar  
if(!fileSplitterFetch.bDownOver) n!r<\4I  
{ (0=e ,1 n  
breakWhile = false; H7 xyK  
break; "0(H! }D  
} [a<u cJ  
} &C.{7ZNt  
if(breakWhile) )r)3.|wJm  
break; H 40~i=.  
7( &\)qf=n  
!`rR;5&sT  
//count++; ^rmcyy8;g  
//if(count>4) 'V=i;2mB*  
// siteStop(); :q.g#:1s  
} tR,&|?0  
i7D)'4gkW  
NT^m.o~4  
System.err.println("文件下载结束!"); LB1AjNJ  
} YQ&Ww|xe  
catch(Exception e){e.printStackTrace ();} 5p.vo"7  
} KZ"&c~[  
<QUjhWxDb  
+ti_?gfx  
//获得文件长度 }W:Rg}v  
public long getFileSize() H+oQ L(i|_  
{ t4RI%m\  
int nFileLength = -1; &.zG?e.  
try{ KkIxtFM  
URL url = new URL(siteInfoBean.getSSiteURL()); g/o@,_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `FjU2 O  
httpConnection.setRequestProperty("User-Agent","NetFox"); J 8z|ua  
"h-G=vo,kl  
[f^:V:) {  
int responseCode=httpConnection.getResponseCode(); g9A8b(>F&@  
if(responseCode>=400) 6`tc]a"#Zb  
{ @2Lp I*]C  
processErrorCode(responseCode); s\)0f_I  
return -2; //-2 represent access is error zPonG d1  
} LRJY63A  
Md4hd#z  
HinPO  
String sHeader; m zh8<w?ns  
{<~oa+"  
$S_xrrE#  
for(int i=1;;i++) M x/G^yO9  
{ ,eI2#6w|C  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3y[6n$U&  
//Utility.log(in.readLine()); ^dR="N  
sHeader=httpConnection.getHeaderFieldKey(i); ;.O#|Z[  
if(sHeader!=null) MY8[)<q"  
{ )Vn(J#s  
if(sHeader.equals("Content-Length"))  }de {-  
{ Yq6e=?-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <sALA~p|0  
break; 7Rba@ cs9  
} Xjy5Yj  
} |6cz r  
else PQu_]cXI  
break; Ix-bJE6+I,  
} > FVBn;1  
} {Dc{e5K  
catch(IOException e){e.printStackTrace ();} N(6Q`zs  
catch(Exception e){e.printStackTrace ();} >1}RiOd3  
4"om;+\  
I%^Bl:M  
Utility.log(nFileLength); K1th>!JW'  
6n|R<DO%\  
p;y\%i_  
return nFileLength; Y#VtZTcT  
} eWN[EJI<  
GOKca%DT=  
,2|(UTv  
//保存下载信息(文件指针位置) Oc Gg'R7  
private void write_nPos() mMNT.a  
{ XF6ed  
try{ 'n>v}__&|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sjZ@}Vk3b  
output.writeInt(nStartPos.length); gB3Tz(!  
for(int i=0;i<nStartPos.length;i++) 4Y2!q$}I+  
{ 8|z@"b l)  
// output.writeLong(nPos); lU`}  
output.writeLong(fileSplitterFetch.nStartPos); H%peE9>$  
output.writeLong(fileSplitterFetch.nEndPos); !Ojf9 6is  
} ^&!S nM  
output.close(); Smt&/~7D%  
} 6m~N2^z  
catch(IOException e){e.printStackTrace ();} 4N!Eqw  
catch(Exception e){e.printStackTrace ();} e5}KzFZmZ  
} LLMom.  
!kTI@103Wd  
)K.'sX{B  
//读取保存的下载信息(文件指针位置) 8]`LRzM  
private void read_nPos() wNfWHaH" m  
{ + a,x  
try{ }akF=/M  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); aqw;T\GI+~  
int nCount = input.readInt();  )S8fFV  
nStartPos = new long[nCount]; l_ES $%d  
nEndPos = new long[nCount]; &OM e'P  
for(int i=0;i<nStartPos.length;i++) e5GJ:2sH  
{ <o aVI?  
nStartPos = input.readLong(); Vx~N`|yY  
nEndPos = input.readLong(); # :)yh]MP  
} V-7A80!5  
input.close(); RBA{!  
} apkmb<  
catch(IOException e){e.printStackTrace ();} mj7Em&  
catch(Exception e){e.printStackTrace ();} Xi:y35q  
} ,rU>)X  
;X z fd  
U2DE zr  
private void processErrorCode(int nErrorCode) ,S%DHT  
{ vNA~EV02  
System.err.println("Error Code : " + nErrorCode);  EOn[!  
} Pf,lZU?f  
]\.3<^  
3G.-JLhs  
//停止文件下载 s|O4 >LsG  
public void siteStop() <5xlP:Cx  
{ O-N@HZC  
bStop = true; PCcI(b>?l  
for(int i=0;i<nStartPos.length;i++) Lj,!0 25  
fileSplitterFetch.splitterStop();  |4_[wX r  
h{Zd, 9H  
gK6_vS4K)  
} m%p;>:"R  
} pR,eus;8  
//负责部分文件的抓取 D-S"?aO-  
**FileSplitterFetch.java j,J/iJs  
*/ {S Oy-  
package NetFox; ~stG2^"[  
?O|CY  
UWPzRk#s"  
import java.io.*; l2S1?*  
import java.net.*; 3c|u2Pl  
m35$4  
~\QN.a   
public class FileSplitterFetch extends Thread { :W6R]y  
*;0Ods+IcY  
,QZNH?Cp/  
String sURL; //File URL xV+cX*4h  
long nStartPos; //File Snippet Start Position q Q/<\6Sl  
long nEndPos; //File Snippet End Position *@-a{T}  
int nThreadID; //Thread's ID AnD#k ]  
boolean bDownOver = false; //Downing is over # VAL\Z  
boolean bStop = false; //Stop identical i uGly~  
FileAccessI fileAccessI = null; //File Access interface 8ED}!;ZU  
Es^=&2 ''  
Q\qI+F2?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {*NM~yQ  
{ upc-Qvk  
this.sURL = sURL; #FwTV@  
this.nStartPos = nStart; dSkx*#FEE  
this.nEndPos = nEnd; 9N*!C{VW  
nThreadID = id; -h`[w:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 iYR`|PJi  
} 6z3`*B  
}[O/u <Z  
c) q'" r  
public void run() -NL=^O$G  
{ y/\0qQ/  
while(nStartPos < nEndPos && !bStop) P6 ~& ,a  
{ 5W4Tp% Lda  
}n;.E&<[  
Pg%k>~i  
try{ G{!adBna  
URL url = new URL(sURL); %'3Y?d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rWS],q=c  
httpConnection.setRequestProperty("User-Agent","NetFox"); 11Y4oS  
String sProperty = "bytes="+nStartPos+"-"; s<b(@L 1  
httpConnection.setRequestProperty("RANGE",sProperty); 9_&N0>OF  
Utility.log(sProperty); 0\tdxi  
TMAart; <  
3zsjL=ta  
InputStream input = httpConnection.getInputStream(); 032PR;]  
//logResponseHead(httpConnection); A` )A=L  
eZ`x[g%1  
$:!L38[7$  
byte[] b = new byte[1024]; 0WO-+eRB/  
int nRead; )>+J`NFa  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _Y 8RP%  
{ {u@w^ hZ$  
nStartPos += fileAccessI.write(b,0,nRead); O[|prk,  
//if(nThreadID == 1) /~6)Vt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d:GAa   
} f`Wces=5  
wVac6q  
QKt+Orz  
Utility.log("Thread " + nThreadID + " is over!"); =Dc9|WuHN  
bDownOver = true; C[2LP$6*/  
//nPos = fileAccessI.write (b,0,nRead); 1yT\|2ARZ%  
} 34s>hm=0.  
catch(Exception e){e.printStackTrace ();} d.:.f_|  
} a$2 WL g,  
} VcpN PU6  
LP:U6 Z  
US2Tdmy@05  
//打印回应的头信息 &?(472<f**  
public void logResponseHead(HttpURLConnection con) daN#6e4Z+;  
{ .~Y% AI  
for(int i=1;;i++) GGF;4  
{ ("T8mt[w>  
String header=con.getHeaderFieldKey(i); /}&@1  
if(header!=null) r]yI5 ;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :j[a X7Sq2  
Utility.log(header+" : "+con.getHeaderField(header)); c,FhI~>R  
else D4;6}gRC  
break; ;UoXj+Z  
} F ?.J1]  
} g6l&;S40  
OaCp3No  
eW.[M?,  
public void splitterStop() {q^?Rw  
{ \rPT7\ZA  
bStop = true; _^Yav.A=  
} n.tJ-l5[  
DfX}^'#m+  
d_w^u|(K  
} `@#,5S$ E  
q+)csgN  
~RIn7/A  
/* d`ESe'j:  
**FileAccess.java 6j5?&)xJ  
*//文件访问(定位,写) QCVwslj,K  
package NetFox; F]k$O$)0  
import java.io.*; BzyzOtBp3L  
," ~4l&  
x39n7+j4  
public class FileAccessI implements Serializable{ XJ9l, :c,  
WlfS|/\%V^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &Dw8GU}1  
RandomAccessFile oSavedFile; #M5[TN!  
long nPos; .p d_SQ~  
qw mZOR#  
o])2_e5  
public FileAccessI() throws IOException F2k)hG*|{  
{ jm$v0=W9#  
this("",0); 5p5S_%R$e  
} ?Rg8u  
B}A7Usm  
G>H',iOI  
public FileAccessI(String sName,long nPos) throws IOException ({l!'>?  
{ ?iQA>P9B  
oSavedFile = new RandomAccessFile(sName,"rw"); wU= @,K  
this.nPos = nPos; 2O~I.(9(  
oSavedFile.seek(nPos); ~IP3~m D  
} 1XvB,DhJ  
2gC.Z:}  
=|G l  
public synchronized int write(byte[] b,int nStart,int nLen) h=Xr J  
{ SpG^kI #  
int n = -1; ?]bZ6|;2  
try{ SOPQg?'n=V  
oSavedFile.write(b,nStart,nLen); rBUdHd9  
n = nLen; eE'2B."F  
} 4lqowg0  
catch(IOException e) QA3q9,C"  
{ )^o7%KX  
e.printStackTrace (); {}TR'Y4  
} SKf[&eP,G  
TXlxnB  
ua -cX3E  
return n; !SFF 79$c  
} Y=#g_(4*  
2Hp#~cE+.  
ZxRD+`  
} tE: m& ;I  
qq+fUfB2:  
!a[1rQH  
/* `Al5(0Q  
**SiteInfoBean.java >|[74#}7  
*/ u}7#3JfLn  
package NetFox; yn[^!GuJ_  
mt+IB4`  
coxMsDs  
public class SiteInfoBean { wM;9plYlw0  
,ij"&XA  
45hjN6   
private String sSiteURL; //Site's URL :(|;J<R%_  
private String sFilePath; //Saved File's Path Ba\l`$%X  
private String sFileName; //Saved File's Name JWa9[Dj  
private int nSplitter; //Count of Splited Downloading File )bqfj>%#c  
'j)xryw  
,4-)  e  
public SiteInfoBean() I]]3=?Y  
{//nSplitter的缺省值为5 rmW,#  
//default value of nSplitter is 5 }wh)I]]U  
this("","","",5); lglC1W-q  
} _d'x6$Jg  
8gv \`  
TvE M{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) A3p@hQl  
{ 3+<}Hm+  
sSiteURL= sURL; LsnM5GU7  
sFilePath = sPath; Bf;dp`(/   
sFileName = sName; !79^M  
this.nSplitter = nSpiltter; u6A ReL 'f  
;~$_A4;  
?*~W  
} BpL,<r,  
4+od N.  
jmbwV,@Q2  
public String getSSiteURL() +-=w`  
{ ysV0Ed  
return sSiteURL; G}d-L!YbE'  
} M1^?_;B  
y]B?{m``6  
ca@0?q#  
public void setSSiteURL(String value) ,BCtNt(  
{ {H+~4XG  
sSiteURL = value; m]8rljo  
} wuCiO;w  
XYtDovbv&  
Kv'2^B  
public String getSFilePath() 05mjV6j7m  
{ G[1:<Vg8  
return sFilePath; t<M^/xe2  
} Y]aVa2!Wb  
cF9bSY_Eh  
5w)tsGX\  
public void setSFilePath(String value) 4k5X'&Q  
{ =EI>@Y"  
sFilePath = value; -y70-K3  
} )-q#hY  
FUic7>  
 ")MjR1p  
public String getSFileName() eAh~ `  
{ }{Ab:+aNd  
return sFileName; 7U> Xi'?  
} f]MKNX  
`iYiAc  
MaDdiyeC  
public void setSFileName(String value) <rZ( B>$  
{ jj2 [Zh/h  
sFileName = value; E|OB9BOS  
} @sUYjB  
W($}G_j[B1  
^'j? { @  
public int getNSplitter() h/E+r:2]  
{ We&~]-b AW  
return nSplitter; ME"B1 Se\  
} 22aS <@}  
Y ;$wD9W  
{"T$j V:GB  
public void setNSplitter(int nCount) tHAr9  
{ P;_}nbB  
nSplitter = nCount; t*H r(|.  
} FCL7Tn  
} !n9H[QP^9  
f]Jn\7j4  
UnSi=uj  
/* )Il) H  
**Utility.java GCaiogiBg  
*/ G?`{OW3:_  
package NetFox; KE>|,U r  
|>_e& }Y%L  
nn[OC=cDN  
public class Utility { P2la/jN  
^3re*u4b=  
L'(ei7Z  
public Utility() je_:hDr  
{ !1G6ZC:z  
}7?n\I+n"  
S7i,oP7  
} F|mppY'<J  
ca )n*SD  
//线程睡眠 -rg >y!L  
public static void sleep(int nSecond) 2F5*C  
{ "[A]tklP  
try{ ^j~CYzmt  
Thread.sleep(nSecond); =CBY_  
} MZJ@qIg[Y  
catch(Exception e) v_U+wga  
{ i2bkgyzB.  
e.printStackTrace (); Xy(8}  
} `Hlv*" w$  
} ZC7ZlL _  
0iS"V^aH  
//日志 PB[ Y^q  
public static void log(String sMsg) a-[:RJW  
{ !*I0}I ~  
System.err.println(sMsg); )gNS%t c*K  
} h"#[{$(  
LDX>S*cL  
1u`{yl*+?  
public static void log(int sMsg) LVHIQ9  
{ <!qN<#$y  
System.err.println(sMsg); PMOyZ3  
} YCBp ]xuE  
} {3)^$F=T  
!H)Cua)  
+K2p2Dw(k  
/* }N^3P0XjYq  
**TestMethod.java 76IjM4&a  
*/ C!,|Wi2&  
package NetFox; )By #({O  
M\m6|P  
,a6Oi=+>/U  
public class TestMethod { b=87k  
9nGS"E l{  
PiL[&_8g  
public TestMethod() `8x.Mv  
{ ///xx/weblogic60b2_win.exe D MzDV_  
try{ 2)-V\:;js  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); s?j||  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N6R0$Br  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +cXdF  
fileFetch.start(); 1uwzo9Yg  
} QV%,s!_b  
catch(Exception e){e.printStackTrace ();} 1r:i'cW h  
P<E!ix  
w^EUBRI-  
} b^s>yN  
;o#wK>pk%M  
.&Ik(792Z&  
public static void main(String[] args) .\rJ|HpZ1J  
{ 1yK=Yf%B  
new TestMethod(); =w,cdU*  
} KtMD?  
} V#Pz `D  
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