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http断点续传简单实现(java)

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/* R%Ui6dCLo  
**SiteFileFetch.java 9k=U0]!ch  
*/ w PG1P'w;  
package NetFox; LL= Z$U $  
import java.io.*; ?u_gXz;A  
import java.net.*; xb+RRTgj  
qLQ <1>u  
kvW|=  
public class SiteFileFetch extends Thread { BrlzN='j}  
9lZAa8Rxi  
nOAJ9  
SiteInfoBean siteInfoBean = null; //文件信息Bean S' (cqO}=F  
long[] nStartPos; //开始位置 @)W(q5)}9"  
long[] nEndPos; //结束位置 .pS&0gBo\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 PcHSm/d0e  
long nFileLength; //文件长度 ~7lTqY\  
boolean bFirst = true; //是否第一次取文件 e-CNQnO~  
boolean bStop = false; //停止标志 :jt;EzCLg%  
File tmpFile; //文件下载的临时信息 vU_d=T%$  
DataOutputStream output; //输出到文件的输出流 T~i%j@Q.6  
w24{_ N  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) X(Y#9N"  
public SiteFileFetch(SiteInfoBean bean) throws IOException P"(z jG9-  
{ ?a'6EAErC  
siteInfoBean = bean; <*s"e)XeqF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^[{`q9A#d  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  G"o!}  
if(tmpFile.exists ()) S=0"f}Jo.  
{ 7|&e[@B  
bFirst = false; X,C*qw@  
read_nPos(); B :.@Qi^  
} GXDC@+$14  
else mu6039qy  
{ s<[A0=LH  
nStartPos = new long[bean.getNSplitter()]; ,O:EX0  
nEndPos = new long[bean.getNSplitter()]; :a_BD  
} ?z2jk  
?QCmSK=L  
o!aLZ3#X  
[##`U m  
} 403[oOj  
YBb)/ZghY  
#O2wyG)oU  
public void run() vU=9ydAj?  
{ "$XYIuT  
//获得文件长度 ,Bisu:v6FW  
//分割文件 ?e F@Q !h  
//实例FileSplitterFetch $4Z+F#mx  
//启动FileSplitterFetch线程 di~]HUZh)  
//等待子线程返回 j|:dYt`WM  
try{ /b{o3, #.M  
if(bFirst) WtEI] WO  
{ !ZFr7Xz  
nFileLength = getFileSize(); F%xK"l`&  
if(nFileLength == -1) \7pipde  
{ ~9Z h,p ;  
System.err.println("File Length is not known!"); 9ky7r;?  
} ;{|X,;s  
else if(nFileLength == -2) <d5@CA+M  
{ o^3FL||P#r  
System.err.println("File is not access!"); >(X #<`  
} H2_/,n  
else 0,HqE='w  
{ JnfqXbE  
for(int i=0;i<nStartPos.length;i++) 4-mVB wq  
{ 3Jk[/ .h  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); H&M1>JtE  
} a:85L!~:l  
for(int i=0;i<nEndPos.length-1;i++) *HR +a#o  
{ 9B /s  
nEndPos = nStartPos[i+1]; {P-xCmZ~Wt  
} $@_{p*q  
nEndPos[nEndPos.length-1] = nFileLength; 93j{.0]X  
} M\Se_  
} a6%@d_A  
bW53" `X  
v? L  
//启动子线程 [ `7%sn]$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3UdU"d[75  
for(int i=0;i<nStartPos.length;i++) v:E;^$6Vn  
{ Yu'a<5f  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L>dkrr)e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 74+A+SK[  
nStartPos,nEndPos,i); ( S`6Q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zDD4m`2  
fileSplitterFetch.start(); aX;A==>  
} hk%k(^ekU]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Hou*lCA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); t8QRi!\=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", F|>05>8  
nEndPos = " + nFileLength); |( G2K'Ab  
// fileSplitterFetch[nPos.length-1].start(); vA=Z=8  
yGxv?%%2  
(&jW}1D  
//等待子线程结束 `H\)e%]  
//int count = 0; v5_7r%Hiw  
//是否结束while循环 "+)K |9T#  
boolean breakWhile = false; OO nX`  
g+xw$A ou  
Ve}[XqdS^p  
while(!bStop) wd[eJcQ,  
{ a d9CsvW  
write_nPos(); 4WC9US-k  
Utility.sleep(500); C-m*?))go  
breakWhile = true; `5q ;ssu  
yEq#Dr  
*^] ~RhjB  
for(int i=0;i<nStartPos.length;i++) Tzzq#z&F  
{ Ytao"R/  
if(!fileSplitterFetch.bDownOver) aBhV3Fd[B  
{ !SO8O  
breakWhile = false; b O=yi)  
break; +L0w;wT  
} zvY+R\,in  
} MuwQZ]u  
if(breakWhile) Ha%F"V*  
break; 2?W7I/F  
5rb-U7 /  
9'nH2,_  
//count++; )0k']g5  
//if(count>4) n2 {SV  
// siteStop(); }s_hD`'  
} [84F0 9HU  
T-gk<V  
g JjN<&,  
System.err.println("文件下载结束!"); er2cQS7R  
} x&Cp> +i  
catch(Exception e){e.printStackTrace ();} .$&Q[r3Lu  
} e4`uVq5  
a^t?vv  
H6K`\8/SeN  
//获得文件长度 )}MHx`KT2  
public long getFileSize() .$!{-v[  
{ #]E(N~  
int nFileLength = -1; ujr(K=E  
try{ GaekFbW)  
URL url = new URL(siteInfoBean.getSSiteURL()); y<- _(^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S QY"OBo<e  
httpConnection.setRequestProperty("User-Agent","NetFox"); t P"\J(x  
u,1}h L  
+/rH(Ni  
int responseCode=httpConnection.getResponseCode(); ,qQG;w,m  
if(responseCode>=400) 3GH(wSv9\  
{ k`\R+WK$  
processErrorCode(responseCode); ]ikomCg   
return -2; //-2 represent access is error -r<#rITH"  
} 3QXjD/h  
[q*%U4qGO  
-.IEgggf  
String sHeader; J~#$J&iKh  
R"AUSO|{  
52d^K0STC  
for(int i=1;;i++) C [uOReo  
{ kW@,$_cK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w%y\dIeI'  
//Utility.log(in.readLine()); ?F7o!B  
sHeader=httpConnection.getHeaderFieldKey(i); C/=XuKE-t  
if(sHeader!=null) +G F#?X0^  
{ 'zZcn" +!  
if(sHeader.equals("Content-Length")) $w#r"= )  
{ #!2k<Q*5uT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); G8Z4J7^  
break; i3VW1~.8  
} S'LZk9E  
} )IL #>2n?  
else .8WXC   
break; ({^9<Us  
} e>}}:Ud  
} \ HZ9S=  
catch(IOException e){e.printStackTrace ();} "TcW4U9  
catch(Exception e){e.printStackTrace ();} Ge+0-I6Ju  
)$ Mmn  
B,WTHU[AV  
Utility.log(nFileLength); BvD5SBa}"  
tV;`fV   
Y&HK1>M_  
return nFileLength; o%E;3l  
} uI~S=;o  
N8r*dadDd  
\x{;U#B[3>  
//保存下载信息(文件指针位置) l_rn++  
private void write_nPos() Z8#Gwyinx  
{ S8d8%R~1=h  
try{ 5kypMHJm  
output = new DataOutputStream(new FileOutputStream(tmpFile)); nmU_N:Y  
output.writeInt(nStartPos.length); Lw1EWN6}_&  
for(int i=0;i<nStartPos.length;i++) .|qK +Hnc  
{ h}`!(K^;3  
// output.writeLong(nPos); JAjmrX  
output.writeLong(fileSplitterFetch.nStartPos); 'XrRhF (  
output.writeLong(fileSplitterFetch.nEndPos); 4+;$7"fJ  
} :O<bA& :d  
output.close(); x%+{VStA  
} d[ >`")2)  
catch(IOException e){e.printStackTrace ();} g*UMG>  
catch(Exception e){e.printStackTrace ();} ;< jbLhHwD  
} Yap?^&GV  
G!N{NCq  
RyJ 1mAC  
//读取保存的下载信息(文件指针位置) )d\ j I  
private void read_nPos() (>4aibA'P  
{ :~Q!SL N  
try{ }R[#?ty;]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $?G"GQ!.  
int nCount = input.readInt(); g>rp@M  
nStartPos = new long[nCount]; l%ayI  
nEndPos = new long[nCount]; oX@ya3!Pz  
for(int i=0;i<nStartPos.length;i++) )tHaB,  
{ 57a2^  
nStartPos = input.readLong(); 'ly?P8h  
nEndPos = input.readLong(); GQQ.OvEc  
} 9>zcBG8f  
input.close(); j$UV/tp5T  
} 2aw&YZ&Xo  
catch(IOException e){e.printStackTrace ();} #`TgZKDg2  
catch(Exception e){e.printStackTrace ();} TGXa,A{  
} B vo5-P6XY  
~\)qi=  
le+R16Z  
private void processErrorCode(int nErrorCode) 0P^L}VVX  
{ u]NZ`t%AP  
System.err.println("Error Code : " + nErrorCode); =*qD4qYA  
} &6 s) X  
`@d<n  
-oeL{9;  
//停止文件下载 uwf 5!Z:>  
public void siteStop() Hs?e0Z=N  
{ E!BPE>  
bStop = true; 7]xm2CHx5  
for(int i=0;i<nStartPos.length;i++) ]M/9#mD9~  
fileSplitterFetch.splitterStop(); RIu~ @  
hz;|NW{u  
Z/x*Y#0@n  
} f<=Fsl  
} ;*ix~taL%  
//负责部分文件的抓取 9)xUA;Qw?z  
**FileSplitterFetch.java )VL96did  
*/ !Fo*e  
package NetFox; Uoya3#4 G  
[ EFMu;q  
Djk C  
import java.io.*; Uz cx6sw  
import java.net.*; 2%*MW"Q  
] Z8Vj7~  
E$9 Ys  
public class FileSplitterFetch extends Thread { t?o ,RN:  
b|Q)[y]  
QB.J,o*XD4  
String sURL; //File URL 4'$g(+z  
long nStartPos; //File Snippet Start Position )jWO P,|  
long nEndPos; //File Snippet End Position 5aad$f  
int nThreadID; //Thread's ID .=m,hu~  
boolean bDownOver = false; //Downing is over x!\ONF5$  
boolean bStop = false; //Stop identical +_XmlX A3Z  
FileAccessI fileAccessI = null; //File Access interface l4n)#?Q?  
H&r,FmI@  
08X_}97#WF  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException j!7`]  
{ y4h=Lki@  
this.sURL = sURL; EbeI{ -'aF  
this.nStartPos = nStart; y\N|<+G+  
this.nEndPos = nEnd; .@ xF6UZ  
nThreadID = id; +("7ZK?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4Mk-2 Dx  
} gaA<}Tp,  
s9dO,FMs0t  
i)#:qAtP*  
public void run() m}>F<;hQ  
{ DAo~8H  
while(nStartPos < nEndPos && !bStop) iAT)VQ&  
{ 8Ll[ fJZA  
LIg{J%  
Dnc(l(  
try{ 1n%?@+W  
URL url = new URL(sURL); .B#l5pfvP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3@5=+z~CW  
httpConnection.setRequestProperty("User-Agent","NetFox"); %m:m}ziLQ  
String sProperty = "bytes="+nStartPos+"-"; zlR?,h-[3  
httpConnection.setRequestProperty("RANGE",sProperty); l5l>d62  
Utility.log(sProperty); I`z@2Z+pJ  
+T9:Udi  
\!]Ua.e<  
InputStream input = httpConnection.getInputStream(); BBcV9CGU  
//logResponseHead(httpConnection); LZMYr  
hhoEb(BA  
f+rz|(6vs{  
byte[] b = new byte[1024]; 4f(Kt,0  
int nRead; 6} FO[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %OgS^_tu  
{ Sq:0w  
nStartPos += fileAccessI.write(b,0,nRead); FU=w(< R;  
//if(nThreadID == 1) Ra*e5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kB5.(O  
} NrP0Ep%V  
GUslPnG  
cb5,P~/q  
Utility.log("Thread " + nThreadID + " is over!"); 2Z20E$Cb  
bDownOver = true; 42>Ge>#F  
//nPos = fileAccessI.write (b,0,nRead); Qt]Q: 9I[  
} e #/E~r&  
catch(Exception e){e.printStackTrace ();} 8kP3+  
} 1-.~7yC  
} p4VeRJk%  
zhY+x<-  
*T0q|P~o%  
//打印回应的头信息 @ 49nJi  
public void logResponseHead(HttpURLConnection con) gm9mg*aM  
{ r>GZ58i  
for(int i=1;;i++) ?xK,mbFgl  
{ Q f(p~a(d  
String header=con.getHeaderFieldKey(i); =@F&o4)r  
if(header!=null) r-,e;o>9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gWY "w!f  
Utility.log(header+" : "+con.getHeaderField(header)); m7T)m0  
else h*ZC*eV>  
break; #07gd#j4  
} :!zl^J;  
} &@ JvnO:  
(knp#   
9'hv%A:\3  
public void splitterStop() };'\~g,1  
{ nC{%quwh{  
bStop = true;  *.)tG  
} 9W5onn  
wcDRH)AW.  
!bV5Sr^  
} ]({~,8s  
qC'{;ko  
VY)s+Bx  
/* 2Pc%fuC  
**FileAccess.java .$@R{>%U  
*//文件访问(定位,写) 86 W0rS[5  
package NetFox; Ecs,$\  
import java.io.*; %v2R.?F8  
H(Eh c  
h<~7"ONhV  
public class FileAccessI implements Serializable{ aZbw]0q@o  
l3 DYg  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1#1 riM -  
RandomAccessFile oSavedFile; u+{a8=  
long nPos; i1 RiGS  
3P;>XGCxZ  
sUPz/Z.h  
public FileAccessI() throws IOException @?"h !fyu  
{ KN-avu_Ix  
this("",0); mS0udHod  
} }`+B=h-dW  
``E/m<r:$  
}<'5 z qS  
public FileAccessI(String sName,long nPos) throws IOException Ks}Xgc\  
{ %\i9p]=  
oSavedFile = new RandomAccessFile(sName,"rw"); &IlU|4`R%  
this.nPos = nPos; /> 4"~q)  
oSavedFile.seek(nPos); Zdn~`Q{  
} @O[5M2|r  
N]RZbzK_5G  
=Fdg/X1  
public synchronized int write(byte[] b,int nStart,int nLen) ]5%/3P,/  
{ }- Wa`t7U  
int n = -1; "*})3['n  
try{ ;t+ub8  
oSavedFile.write(b,nStart,nLen); jbR0%X2  
n = nLen; E\C9|1)  
} K(q-?n`<  
catch(IOException e) [k-+AA>:  
{ >$2V%};  
e.printStackTrace (); "le>_Ze_>|  
} p0pWzwTG3  
?mlNL/:  
*_?dVhxf  
return n; + T8B:  
} uw2hMt (N  
D.mHIsX6\  
/JT#^Y  
} a.z;t8  
/q5:p`4{J  
IUwm}9Q!  
/* S%`0'lzzj  
**SiteInfoBean.java (T2m"Yi:  
*/ XQS9,Hl  
package NetFox; Zv#Ll@v  
!A%<#Gjt  
rylzcN9RM$  
public class SiteInfoBean { M}!2H*  
PiA0]>  
Q~T$N  
private String sSiteURL; //Site's URL {P*m;a`}  
private String sFilePath; //Saved File's Path KIWe@e  
private String sFileName; //Saved File's Name xNbPsoK  
private int nSplitter; //Count of Splited Downloading File yiO. z  
F8apH{&t  
50={%R  
public SiteInfoBean() |DsnNk0c  
{//nSplitter的缺省值为5 xt*u4%  
//default value of nSplitter is 5 ~*wk6&|  
this("","","",5); {D=@n4JO  
} f;b[w   
,N0#!<}4  
H *)NLp  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +>PX&F  
{ 6 :~v4W!k  
sSiteURL= sURL; )P+7PhE{J  
sFilePath = sPath; SCz318n  
sFileName = sName; %V nbmoO  
this.nSplitter = nSpiltter; /bVoErf  
Gn&4V}F  
!@v7Zu43,  
} @mfEKU!  
ynrT a..  
^U!0-y  
public String getSSiteURL() Er{>p|n =  
{ yNTK .  
return sSiteURL; ej"+:. "\e  
} hq #?kN  
\o^2y.q:>  
j*vYBGD  
public void setSSiteURL(String value) #Q /Arq  
{ =y-@AU8  
sSiteURL = value; $b mLu=9  
} a0#J9O_  
(I./ Uu%  
1 .6:#  
public String getSFilePath() .;N1N^  
{ ( U xW;  
return sFilePath; _FWBUZ;N  
} <Sr  
[)TRTxFb  
bR)(H%I  
public void setSFilePath(String value) 9_5ow  
{ ^RI?ybDd  
sFilePath = value; :n-]>Q>5=k  
} s ']Bx=  
PGoh1Uu  
.~7FyLl$  
public String getSFileName() @8I4[TE  
{ _+E5T*dk  
return sFileName; {Sj9%2'M)  
} H|HYo\@F#  
VB*oGG  
XSyHk"g`  
public void setSFileName(String value) |0f>aZ  
{ r<d_[?1N  
sFileName = value; 4.5|2 \[  
} gK'1ZLdZ2  
OD!& .%  
<d$x.in  
public int getNSplitter() JVSA&c%3  
{ ybKWOp:O  
return nSplitter; )`(p9@,V  
} #$8% w  
XLrwxj0  
}*S `qW;B  
public void setNSplitter(int nCount) yvO{:B8%  
{ |M, iM]  
nSplitter = nCount; m0a?LY  
} (bH`x]h#  
} gq'Y!BBQy  
z)r =+ -  
E;R n`oxk  
/* '$ t  
**Utility.java I!Z_ [M  
*/ lrIjJ V  
package NetFox; 7%|~>  
J`].:IOh  
oUQ,61H  
public class Utility { ^Xq 6:  
TI,&!E?;  
FwkuC09tI  
public Utility() HOJs[mqB%  
{ (Fhs"  
WGZ9B^A  
 jYmR  
} SPY|K  
Ssou  
//线程睡眠 dQA'($  
public static void sleep(int nSecond) UMm!B`M  
{ biU^[g("  
try{ -7@/[9Gf`:  
Thread.sleep(nSecond); ij(B,Y  
} TU,s*D&e  
catch(Exception e) m!tbkZHQn0  
{ Enn"hdI  
e.printStackTrace (); 1;Cyz)  
} LcTt)rs f  
} D"2&P^-  
BMG3|N^  
//日志 xg;+<iW  
public static void log(String sMsg) _ 4U5  
{ ?kH8Lw~{5W  
System.err.println(sMsg); Z8@J`0x  
} xRzFlay8  
1q:2\d]  
Tz8PSk1[  
public static void log(int sMsg) v50bdj9}k  
{ #mCL) [  
System.err.println(sMsg); iXVe.n  
} 1AM!8VR2  
} $!-c-0ub  
R6kD=JY/!  
J\:R|KaP<p  
/* 7WkB>cn  
**TestMethod.java ,*&:2o_r  
*/ _u5#v0Y  
package NetFox; $0>60<J  
>_-s8t=|  
zuJ@E=7  
public class TestMethod { KWowN;  
e478U$  
G\Cp7:j}  
public TestMethod() vgH3<pDiU6  
{ ///xx/weblogic60b2_win.exe t\~P:"  
try{ |y!=J$ $_H  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~=6xyc/c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j<V Fn~*_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); e.7EU  
fileFetch.start(); m.# VYN`+A  
} p.v0D:@&  
catch(Exception e){e.printStackTrace ();} QkEvw<  
8*#R]9  
s%nUaWp~  
} S1Wj8P-  
*`ua'"="k  
n 22zq6m  
public static void main(String[] args) ~J wb`g.  
{ RKHyw 08  
new TestMethod(); !;Yg/'vD-  
} cl=EA6P\X  
} aQ?/%\>  
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