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http断点续传简单实现(java)

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/* {+~}iF<%  
**SiteFileFetch.java g?,\bmHE  
*/ _t[RHrs  
package NetFox; QkbXm[K.Z  
import java.io.*; )cnH %6X  
import java.net.*; `I|$U)'  
b77Iw%x7  
Cf@~W)K  
public class SiteFileFetch extends Thread { -xg$qvK  
D:`b61sWi_  
kSJWXNC  
SiteInfoBean siteInfoBean = null; //文件信息Bean O_%X>Q9  
long[] nStartPos; //开始位置 .U.Knn  
long[] nEndPos; //结束位置 3^m0 k E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 nrqr p  
long nFileLength; //文件长度 cMxuG'{=.  
boolean bFirst = true; //是否第一次取文件 )kLTyx2&  
boolean bStop = false; //停止标志 1?:/8l%V  
File tmpFile; //文件下载的临时信息 A")F7F31c  
DataOutputStream output; //输出到文件的输出流 jK`b6:#(,  
_a?c,<A  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) HCOv<k  
public SiteFileFetch(SiteInfoBean bean) throws IOException J1P jMb}  
{ fmqHWu*wG  
siteInfoBean = bean; F@ Sw  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); DZPg|*KT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); sfb)iH|sW  
if(tmpFile.exists ()) W=zHD 9  
{ (^h2 'uB  
bFirst = false; %UGXgYDz  
read_nPos(); ?T.'  q  
} Er@'X0n  
else BO5\rRa0  
{ =$kSvCjP  
nStartPos = new long[bean.getNSplitter()]; l X g.`  
nEndPos = new long[bean.getNSplitter()]; FU]jI[  
} p./9^S  
ngmHiI W  
,3+#?H  
UNK}!>HD  
} _.)6~  
2c)Ez?  
{=3&_/9s){  
public void run() ~w Ekbq=  
{ r}?uZ"]=?  
//获得文件长度 PBkTI2 v  
//分割文件 i n $~(+  
//实例FileSplitterFetch b!lS=zIN  
//启动FileSplitterFetch线程 hj4!* c  
//等待子线程返回 "pRi1Y5)l  
try{ @Z}TF/Rx4  
if(bFirst) ' ozu4y  
{ _ tba:a(  
nFileLength = getFileSize(); t3P$UR%  
if(nFileLength == -1) Qs\m"yx  
{ GXk]u  
System.err.println("File Length is not known!"); Pp{Re|.  
} KE$I!$zO  
else if(nFileLength == -2) _bsAF^ ;  
{ UnVYGch  
System.err.println("File is not access!"); -l(G"]tRB  
} i#4}xvi  
else g \;,NW^  
{ SN#Cnu}  
for(int i=0;i<nStartPos.length;i++) o5h*sQ9  
{ $?Dcp^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J 2H$ALl  
} a_z1S Z2[  
for(int i=0;i<nEndPos.length-1;i++) V*d@@%u**  
{ nO#a|~-))  
nEndPos = nStartPos[i+1]; |K.J@zW  
} n{*A<-vL  
nEndPos[nEndPos.length-1] = nFileLength; Rz03he  
} c^F@9{I  
} i]$/& /  
WALK@0E  
xI>HY9i )  
//启动子线程 rbw~Ml0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /#Gm`BT  
for(int i=0;i<nStartPos.length;i++) ]broU%#"  
{ r]3v.GZy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yg WwUpY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), HrK7qLw7  
nStartPos,nEndPos,i); 'hNRIM1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *KYh_i  
fileSplitterFetch.start(); x'iBEm  
} Ewq7oq5:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $z,rN\[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); k*ZYT6Z?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W.sH  
nEndPos = " + nFileLength); $aC%&&+wG  
// fileSplitterFetch[nPos.length-1].start(); HO}eu  
F 9J9zs*,  
19]O;  
//等待子线程结束 JWsOze 8#  
//int count = 0; "ivSpec.V  
//是否结束while循环 /St d6B*  
boolean breakWhile = false; Hd ${I",  
Uqd2{fji=#  
lPA:ho/`:  
while(!bStop) ?WBA:?=$58  
{ g0 k{b  
write_nPos(); ;mauA#vd  
Utility.sleep(500); zwgO|Qg;  
breakWhile = true; ,R*YI  
f)#nXTXeC  
7hAc6M$h;  
for(int i=0;i<nStartPos.length;i++) |IZFWZd  
{ t@cImmh\T  
if(!fileSplitterFetch.bDownOver) ^K?Mq1"Db  
{ h,x'-]q  
breakWhile = false; 28,g'k!  
break; @u1mC\G  
} bnxR)b~  
} D8=a+!l-  
if(breakWhile) D {N,7kT  
break; 4>Y\Y$3  
3h4'DQ.g  
.]LP327u  
//count++; gPY Cw?zQ  
//if(count>4) $@eFSA5k,7  
// siteStop(); ;hkzL_' E)  
} T?EFY}f  
GcHZ&m4  
WXX08"  
System.err.println("文件下载结束!"); *6QmYq6c<  
} c n^z=?  
catch(Exception e){e.printStackTrace ();} u= ydX  
} Wu U_R E  
='vkd=`Si  
P7y.:%DGD0  
//获得文件长度 <lf6gb  
public long getFileSize() \Z/# s;c,4  
{ i1-wzI  
int nFileLength = -1;  $&to(  
try{ }x+s5a;!3/  
URL url = new URL(siteInfoBean.getSSiteURL()); x>MY_?a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y5\=5r/  
httpConnection.setRequestProperty("User-Agent","NetFox"); &BkdC,o  
gB}UzEj^<  
$LJCup,1"  
int responseCode=httpConnection.getResponseCode(); k%h%mz  
if(responseCode>=400) T)#eaz$4W  
{ $#7~  
processErrorCode(responseCode);  rhO 8v  
return -2; //-2 represent access is error {"@E_{\  
} +^V%D!.$@  
nI<Ab_EB  
|emZZj  
String sHeader; ]?n~?dD{]  
j[&C6l+wH  
yUlYf#`H  
for(int i=1;;i++) p'YNj3&u  
{ z]0UW\S/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F'3-*>]P  
//Utility.log(in.readLine()); ca?;!~%zA  
sHeader=httpConnection.getHeaderFieldKey(i); O K2|/y  
if(sHeader!=null) BZs?tbf  
{ \"AzT{l!;  
if(sHeader.equals("Content-Length")) zR6^rq*  
{ % #-'|~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6),VN>j  
break; "&N1$$  
} X.hV MX2B  
} YMIX|bj6Y  
else 2[TssJQ  
break; :P: OQ[$  
}  mIkc +X  
} vGI?X#w3  
catch(IOException e){e.printStackTrace ();} D?@e,e  
catch(Exception e){e.printStackTrace ();} @g==U{k;t  
_do(   
<s(<ax30  
Utility.log(nFileLength); ,]8$QFf  
Q(7M_2e7  
)ZQML0}P;  
return nFileLength; D$/*Z5Z)]  
} D_-<V,3t  
AZ& ]@Ao  
5Q.z#]L g  
//保存下载信息(文件指针位置) ,`;Dre  
private void write_nPos() O*y@4AR"S  
{ dRPX`%J  
try{ xH/Pw?^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &s<'fSI  
output.writeInt(nStartPos.length); /6d:l>4  
for(int i=0;i<nStartPos.length;i++) = *~Q5F  
{ z{ydP Ra  
// output.writeLong(nPos); XbL\l  
output.writeLong(fileSplitterFetch.nStartPos); /8tF7Mmr  
output.writeLong(fileSplitterFetch.nEndPos); A3c&VT6Q  
} ;,Q6AS!  
output.close(); /;\{zA$uC=  
} YMTB4|{  
catch(IOException e){e.printStackTrace ();} { 0 vHgi  
catch(Exception e){e.printStackTrace ();} eE-c40Bae  
} (v$$`zh  
1pHt3Vc(G  
>5+]~[S  
//读取保存的下载信息(文件指针位置) s^Wh!:>r/  
private void read_nPos() ~<&47'D  
{ ye-R  
try{ _Vf0MU;3f+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); bRb+3au_x  
int nCount = input.readInt(); ~f:jI1(}  
nStartPos = new long[nCount]; |m /XGr  
nEndPos = new long[nCount]; =x3ZQA  
for(int i=0;i<nStartPos.length;i++) E#A}J:  
{ #(Ah>y  
nStartPos = input.readLong();  wk (}q  
nEndPos = input.readLong(); a0=5G>G9c  
} 5Sfz0  
input.close(); KD)+& 69  
} N0 F|r8xS  
catch(IOException e){e.printStackTrace ();} |jwN8@  
catch(Exception e){e.printStackTrace ();} p.J+~s4G  
} <4QOjW  
 T%p/(  
)i{B:w\ ^  
private void processErrorCode(int nErrorCode) =(U&?1R4  
{ >7^i>si  
System.err.println("Error Code : " + nErrorCode); [r"`r Bw  
} ~Q/G_^U:  
tW#=St0<.o  
j/Rm~!q  
//停止文件下载 ZQQ0}  
public void siteStop() f}U@e0Lsb  
{ %HK\  
bStop = true; {Y#$  
for(int i=0;i<nStartPos.length;i++) MEZc/Ru-[  
fileSplitterFetch.splitterStop(); @5y ~A}Vd  
hJcN*2\:  
x&PVsXdt5m  
} ,@*Srrw  
} uY'77,G_J  
//负责部分文件的抓取 i9%cpPrg8  
**FileSplitterFetch.java fR6.:7&  
*/ %juR6zB%8  
package NetFox; F4%vEn\!  
5v@-.p  
ywS2` (  
import java.io.*; qq1@v0  
import java.net.*; Z}*{4V`R  
1__Mf.A  
%x G3z7;  
public class FileSplitterFetch extends Thread { :?.RZKXQF  
js#72T/_n  
L&s|<<L  
String sURL; //File URL rS3* k3  
long nStartPos; //File Snippet Start Position 6 s$jt-bH  
long nEndPos; //File Snippet End Position /y<nAGtD&  
int nThreadID; //Thread's ID K@UQ O  
boolean bDownOver = false; //Downing is over TUaW'  
boolean bStop = false; //Stop identical "X7;^yY  
FileAccessI fileAccessI = null; //File Access interface Q lg~S1D_v  
39+6ZTqx  
g.re`m|Aj  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException w2/3\3p  
{ !33)6*s  
this.sURL = sURL; a~nErB  
this.nStartPos = nStart; ?U;KwS]%  
this.nEndPos = nEnd; JM?X]l  
nThreadID = id; K V-}:u(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >TqMb8e_  
} JO `KNI  
ZXR#t?D  
&bO5+[  
public void run() lIlmXjL0  
{ ^KeJ=VT  
while(nStartPos < nEndPos && !bStop) ].C4RH  
{ jg7 WMH"`  
}&{z-/;H  
I3wv6xZ2  
try{ ub* j&L=  
URL url = new URL(sURL); X\a*q]"_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c+^#(OB  
httpConnection.setRequestProperty("User-Agent","NetFox"); D<35FD,  
String sProperty = "bytes="+nStartPos+"-"; ue;o:>G  
httpConnection.setRequestProperty("RANGE",sProperty); m.K@g1G  
Utility.log(sProperty); ^XIVWf#`H  
;=?f0z<  
dmkd.aP4  
InputStream input = httpConnection.getInputStream(); &S8Pnb)d  
//logResponseHead(httpConnection); zAxscD f'  
E =7m@"0  
I|#1u7X%]  
byte[] b = new byte[1024]; \~#$$Q-qtU  
int nRead; *Ou)P9~-L  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]tzO)c)w;  
{ zL<<`u?  
nStartPos += fileAccessI.write(b,0,nRead); [ 4_JK  
//if(nThreadID == 1) ;F;"Uw  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1Y-m=~J7  
} TL?(0]H fe  
2unaK<1s  
MzY~-74aF  
Utility.log("Thread " + nThreadID + " is over!"); .-Xp]>f,  
bDownOver = true; 'K9{xI@N  
//nPos = fileAccessI.write (b,0,nRead); 69o,T`B  
} ~baVS-v  
catch(Exception e){e.printStackTrace ();} mimJ_=]DC  
} 0xe!tA  
} tL;!!vg#V  
LXm5f;  
DD4fV`:kG  
//打印回应的头信息 [= GVK  
public void logResponseHead(HttpURLConnection con)  >Mzk;TM  
{ }c"1;C&{  
for(int i=1;;i++) jv C.T]<B  
{ .=nx5y z  
String header=con.getHeaderFieldKey(i); ![{>$Q?5  
if(header!=null) ;B'5B]A3  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); NX?IM8\t  
Utility.log(header+" : "+con.getHeaderField(header)); Y)-)owx7  
else (|F} B  
break; c)HHc0KD  
} 9b/7~w.  
} )tRqt9Th*  
sU/R$Nbr  
7HpfHqJ7  
public void splitterStop() =ca<..yh[d  
{ aa'u5<<W  
bStop = true; $p)7k   
} huu v`$~y  
*7ggw[~  
Kf.G'v46  
} |9;6Cp  
,EAf/2C  
!&3iZQGWv  
/* ~is$Onf99#  
**FileAccess.java q:y_#r"_y  
*//文件访问(定位,写) /lC&'hT  
package NetFox; sUfYEVjr  
import java.io.*; >|"mhNF  
_m  *8f\  
lO)0p2  
public class FileAccessI implements Serializable{ 7^fpbrj  
lYS+EVcR  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 me#?1r  
RandomAccessFile oSavedFile; $ON4 nx  
long nPos; abHW[VP9  
Vu%XoI)<KY  
AF=9KWqf  
public FileAccessI() throws IOException 3N'fHy  
{ 2f%G`4/p  
this("",0); 6%p$C oR  
} ^&AhW m7\  
wc3OOyP@0  
HOn,c@.9Y  
public FileAccessI(String sName,long nPos) throws IOException C/JeD-JG  
{ ?HP54G<{xz  
oSavedFile = new RandomAccessFile(sName,"rw"); ],fu#pi=]  
this.nPos = nPos; QJcaOXyMS  
oSavedFile.seek(nPos); zH1pW(  
} 5kK:1hH7  
O:=%{/6&D  
n9;z=   
public synchronized int write(byte[] b,int nStart,int nLen) p m4g),s  
{ v{N4*P.0T  
int n = -1; Y1?"Ut  
try{ /-#1ys#F=  
oSavedFile.write(b,nStart,nLen); ^ lUV^%f  
n = nLen; Qg7rkRia  
} a w0;  
catch(IOException e) "k8Yc<`u  
{ b.`<T "y  
e.printStackTrace (); ;{n@hM*O  
} e b])=  
.H M1c  
Y: ~A-_  
return n; GwOn&EpY!  
} BEQ$p) h  
8sDbvVh1F  
23lLoyN  
} x}g5  
ECO4ut.d  
W>ziA  
/* {*=+g>R gD  
**SiteInfoBean.java UBmD 3|Zo  
*/ re\@v8w~  
package NetFox; LqH<HGMFD  
7j>NUx=j3  
?e`4 s f_~  
public class SiteInfoBean { -+'fn$  
19Cs 3B\4  
<Rs#y:  
private String sSiteURL; //Site's URL }~?B>vZS  
private String sFilePath; //Saved File's Path u,zA^%   
private String sFileName; //Saved File's Name x>>#<hOz[  
private int nSplitter; //Count of Splited Downloading File 'IorjR@ 40  
FS3MR9  
h>'9-j6B  
public SiteInfoBean() |WopsV %  
{//nSplitter的缺省值为5 pjC2jlwm*  
//default value of nSplitter is 5 b7 pD#v  
this("","","",5); !)jw o=l}J  
} W+A-<Rh\  
tQSj[Yl  
Qy)+YhE  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Xq3n7d.  
{ LvWl*:z  
sSiteURL= sURL; ,0'Yj?U>  
sFilePath = sPath; >m}U|#;W  
sFileName = sName; ]Qo.X~]  
this.nSplitter = nSpiltter; nkKiYr  
56;(mbW  
)'<B\P/  
} ^2gDhoO_  
+`EF0sux  
R W= <EF&  
public String getSSiteURL() 6GxQ<  
{ y$n7'W6  
return sSiteURL; [m9Pt]j@  
} ]L'FYOfrpx  
)Ir_:lk  
$/\b`ID  
public void setSSiteURL(String value) T ;Ga G  
{ NDw+bR-  
sSiteURL = value; 59?@55  
} -#=y   
.k{omr&Dy5  
|G2hm8 Y  
public String getSFilePath() xwjim7# _:  
{ 1E(~x;*)  
return sFilePath; N30w^W&  
} %+WIv+ <  
Fq{Z-yVp  
)V!9/d  
public void setSFilePath(String value) r52X}Y  
{ '~dE0ohWb  
sFilePath = value; K3eYeXV  
} w#?@ulr]d  
8q)wT0A~  
T Y|5O! <  
public String getSFileName() <OKzb3e  
{ x+kP,v  
return sFileName; -ff|Xxar{  
} -{Lc?=  
F1V[8I.0  
U'pm5Mc\q  
public void setSFileName(String value) Zk#^H*jgx  
{ z3l= aAw8  
sFileName = value; &*G+-cF  
} mhp&; Q9  
jzuOs,:R  
/PP\L](  
public int getNSplitter() cJEO wAN  
{ TBfX1v|Z)  
return nSplitter; O"otzla  
} ^y@ RfM=A  
e=11EmN9  
];bl;BP  
public void setNSplitter(int nCount) Z[.+Wd\)-9  
{ oB9t&yM  
nSplitter = nCount; d^"dL" Q6m  
} #!Iez vWf  
} o<`)cb }  
Sz\"*W;>  
^wL n  
/* )4d)G5{  
**Utility.java t 6.hg3Y  
*/ m){.{Vn]  
package NetFox; q!iMc  
L  lP  
Qm| Q0u   
public class Utility { '4PAH2&n  
,&S ^Ryc  
U @Il:\I  
public Utility() u-W6 hZ$  
{ :Zy7h7P,lT  
-+1it  
^*7~ Wxk5  
} Nw'3gJ:  
j@0/\:1(U  
//线程睡眠 ;T0Y= yC  
public static void sleep(int nSecond) c#q OK  
{ |aiP7C  
try{ %IS'R`;3  
Thread.sleep(nSecond); ALw5M'6q0\  
} ={9G.%W  
catch(Exception e) [\o+I:,}wi  
{ 1v TncU!  
e.printStackTrace (); P)fv:a  
} b\zRwp  
} >uN`q1?l'  
 \Vis  
//日志 &"dT/5}6  
public static void log(String sMsg) _VU/j9<+  
{ ,}M@Am0~  
System.err.println(sMsg); ETP}mo  
} d*26;5~\  
!GkwbHr+p  
im&E \`L7  
public static void log(int sMsg) 0NLoqq  
{ B;'Dh<J1  
System.err.println(sMsg); cH>rS\|Y  
} Si<9O h  
} ^7`"wj14  
0_Hdj K  
2e}${NZN  
/* fP`g#t)4Tu  
**TestMethod.java /^~3Ib8Fw+  
*/ $tyF(RybG  
package NetFox; ?iH`-SY  
Ti/t\'6  
r3o_mO?X  
public class TestMethod { L&1VPli  
(~/VP3.S  
!UE' AB  
public TestMethod() D_GIj$%N[  
{ ///xx/weblogic60b2_win.exe yD iL  
try{ q<>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @%L4^ms  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ![WX -"lW  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Nw@tlT4  
fileFetch.start(); DG8LoWZ  
} >;',U<Wd  
catch(Exception e){e.printStackTrace ();} k%\_UYa  
**rA/*Oc  
 `"v5bk  
} .BGM1ph}~  
"|CzQ&e  
qkC+9Sk  
public static void main(String[] args) QRnkj]b  
{ ~je#gVoUR  
new TestMethod(); JGPLVw  
} >=hO jV;  
} UhCE.# U  
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