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http断点续传简单实现(java)

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/* 6bf!v  
**SiteFileFetch.java a/%qn-i|p  
*/ Lo}/k}3Sx  
package NetFox; ~Q]::  
import java.io.*; 9c{ ~$zJW  
import java.net.*; o{mVXidE  
#D >:'ezm  
FZ8Qj8  
public class SiteFileFetch extends Thread { F6h IG G  
[w+1<ou;j  
O%&N6U  
SiteInfoBean siteInfoBean = null; //文件信息Bean UCTc$3  
long[] nStartPos; //开始位置 1$m{)Io2(  
long[] nEndPos; //结束位置 2) 2:KX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2IkyC`  
long nFileLength; //文件长度 }ZiJHj'<  
boolean bFirst = true; //是否第一次取文件 eV;nTj  
boolean bStop = false; //停止标志 Q yQ[H  
File tmpFile; //文件下载的临时信息 C}9|e?R[Rz  
DataOutputStream output; //输出到文件的输出流 $!\L6;:  
n+vv %  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 5fmQ+2A C1  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?PV@WrU>B  
{ 'CG% PjCO  
siteInfoBean = bean; t [G7&ovj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9p4SxMMO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :)+)L@By  
if(tmpFile.exists ()) M}=fdH  
{ uY3#,  
bFirst = false; Uqly|FS &n  
read_nPos(); Ms+SJ5Lg  
} !rG-[7K  
else _,p/2m-Pj  
{ 3 rLc\rK  
nStartPos = new long[bean.getNSplitter()]; N5xI;UV9'  
nEndPos = new long[bean.getNSplitter()]; }C~9 ?Y  
} rvb@4-i>iI  
|H 5$VSw  
oj ,;9{-  
z 5~X3k7  
} Pb59RE:7V  
8CvNcO;H0  
GQE7P()  
public void run() A43[i@o  
{ Kc>Rd  
//获得文件长度 \vW'\}  
//分割文件 {L M Q  
//实例FileSplitterFetch /}5)[9GC  
//启动FileSplitterFetch线程 Q} g"pl  
//等待子线程返回 ]^@m $O  
try{ PevT`\>  
if(bFirst) VZ9`Kbu  
{ VQ+G.  
nFileLength = getFileSize(); b,(<74!#8  
if(nFileLength == -1) v~YGef;D  
{ .9<euPrz  
System.err.println("File Length is not known!"); d zV2;  
} @%^h|g8>Fu  
else if(nFileLength == -2) )E6E}  
{ ^Q!A4 qOQ  
System.err.println("File is not access!"); &u (pBr8B  
} 8Qkwg]X  
else OY!WEP$F-C  
{ JbXi|OS/  
for(int i=0;i<nStartPos.length;i++) F C=N}5u  
{ 9*r l7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); e8z?) 4T  
} <DEu]-'>  
for(int i=0;i<nEndPos.length-1;i++) $bZ5@)E  
{ *I k/Vu%;  
nEndPos = nStartPos[i+1]; |"eC0u  
} :G5O_T$  
nEndPos[nEndPos.length-1] = nFileLength; 5mm&l+N)  
} A3.pz6iT>  
} 1h{7dLA  
5/HkhT yj  
(/i|3P  
//启动子线程 Rgz zbW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; e :@PI(P!  
for(int i=0;i<nStartPos.length;i++) YH{n   
{ ?rdWhF]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R~RE21kAc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), shVEAT'`  
nStartPos,nEndPos,i); |HwEwL+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7DeBeY  
fileSplitterFetch.start(); # `@jVX0  
} w@a|_?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ')(U<5y)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); acj-*I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3u,B<  
nEndPos = " + nFileLength); M L7vP  
// fileSplitterFetch[nPos.length-1].start(); +\>op,_9I  
Q>L.  
@q{.shqo  
//等待子线程结束 nu[["f~  
//int count = 0; g5*?2D}dqX  
//是否结束while循环 /?}2OCq  
boolean breakWhile = false; /9?yw!  
0XA0 b1VX  
yFTN/MFt  
while(!bStop) ]Z*B17//  
{ <s'0<e!./t  
write_nPos(); 65rf=*kz:  
Utility.sleep(500); Mh@n>+IR  
breakWhile = true; LeNSjxB  
m'uFj !  
"@Qg]#]JH  
for(int i=0;i<nStartPos.length;i++) !=6\70lJ  
{ v:NQrN  
if(!fileSplitterFetch.bDownOver) g)IW9q2  
{ UM^~a$t  
breakWhile = false; #E_<}o  
break; #+|0o-  
} qga?-oz,<6  
} R|_._Btu!  
if(breakWhile) r,P`$-  
break; NT9|``^Z  
*thm)Mn  
J.c yb  
//count++; @Z<Z//^k  
//if(count>4) XS.*CB_m_  
// siteStop(); vr_Z0]4`C9  
} bP4}a!t+n  
4"\%/kG  
WzBr1 ea{I  
System.err.println("文件下载结束!"); D4~]:@v~n  
}  nL[G@1nR  
catch(Exception e){e.printStackTrace ();} S[N9/2  
} ff00s+  
x_wWe>0  
`dRqheX  
//获得文件长度 4Ofkagg  
public long getFileSize() Xc L%0%`  
{ mo&9=TaG  
int nFileLength = -1; `^h:} V  
try{ q*cEosi'F?  
URL url = new URL(siteInfoBean.getSSiteURL()); {*K$gH$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0: B%,n UM  
httpConnection.setRequestProperty("User-Agent","NetFox"); Sar1NkD#  
.=9d3uWJ/  
Xx\,<8Xn  
int responseCode=httpConnection.getResponseCode(); e -b>   
if(responseCode>=400) GH`y-Ul'K  
{ 4^:$|\?]  
processErrorCode(responseCode); (ki= s+W-  
return -2; //-2 represent access is error 0!tuUn  
} rU 1Ri  
ACpecG  
QuC_sFP10  
String sHeader; _7dp(R  
,,lR\!>8  
"CZv5)  
for(int i=1;;i++) M; YJpi  
{ 32`Z3-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); WADEDl&,'  
//Utility.log(in.readLine()); js% n]$N  
sHeader=httpConnection.getHeaderFieldKey(i); 0;hn;(V]"  
if(sHeader!=null) UKPr[  
{ ,RP9v*  
if(sHeader.equals("Content-Length"))  {@k , e  
{ > }kZXeR|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [8K :ml  
break; Sf@xP.d  
} q4,/RZhzh  
} dXsD%sG @  
else OU!."r`9  
break; -"?~By}<C  
} l+X\>,  
} d ,.=9  
catch(IOException e){e.printStackTrace ();} ]EG8+K6  
catch(Exception e){e.printStackTrace ();} A8Km8"  
4vCUVo r  
.}:*tvot  
Utility.log(nFileLength); 4t>"-/  
k$pND,Ws  
Tr;.O?@{t}  
return nFileLength; wc&D[M]-/  
} 7 NnXt'  
z#GSt ZT  
;<"V}, C  
//保存下载信息(文件指针位置) 0Gu?;]GSv  
private void write_nPos() k"%sdYkb!  
{ >qmNT/  
try{ DfVJ~,x~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); O- LwX >  
output.writeInt(nStartPos.length); M}q;\}  
for(int i=0;i<nStartPos.length;i++) Y/T-q<ag8  
{ PWkSl  
// output.writeLong(nPos); zS h9`F  
output.writeLong(fileSplitterFetch.nStartPos); *zW]IQ'A  
output.writeLong(fileSplitterFetch.nEndPos); -)R =p"-w  
} 9<3fH J?vq  
output.close(); #zBqj;p  
} !!w(`kmn1  
catch(IOException e){e.printStackTrace ();} $\bVu2&I  
catch(Exception e){e.printStackTrace ();} VN'\c3;  
} S(CVkCP  
'f CSP|  
LXPO@2QF  
//读取保存的下载信息(文件指针位置) 2A9crL $  
private void read_nPos() C%CgWO`Xj  
{ q?@*  
try{ v>N*f~n  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Wu(^k25  
int nCount = input.readInt(); _x^rHADp  
nStartPos = new long[nCount]; 1}+b4 "7]  
nEndPos = new long[nCount]; n$9Xj@  +  
for(int i=0;i<nStartPos.length;i++) L 4Z+8*  
{ 7AWq3i{  
nStartPos = input.readLong(); A}&YK,$5ED  
nEndPos = input.readLong(); .rnT'""i<5  
} rBy0hGx  
input.close(); 62y:i  
} xtKU;+#  
catch(IOException e){e.printStackTrace ();} 6a_U[-a9;  
catch(Exception e){e.printStackTrace ();} a'. 7)f[g}  
} \fuz`fK:  
2)T;N`tNw  
b?qV~Dg k`  
private void processErrorCode(int nErrorCode) ] @#wR  
{ o>bi~(H  
System.err.println("Error Code : " + nErrorCode); q/d?c Lgl  
} yPs6_Qo!p  
>Gk<a  
po,U e>n/  
//停止文件下载 *ZFF$0}  
public void siteStop() J9DI(`  
{ {9.UeVz  
bStop = true; 3IB9-wG  
for(int i=0;i<nStartPos.length;i++) *X ;ch55\  
fileSplitterFetch.splitterStop(); u0G tzk  
`%"x'B`mM  
&K(y%ieIJ  
} /e*fsQ>M:  
} #y[omla8  
//负责部分文件的抓取 c h((u(G  
**FileSplitterFetch.java  7Z<GlNv  
*/ (n7{?`Yid  
package NetFox; #g0N/  
 Fq5u%S  
! Vlx  
import java.io.*; I,HtW),  
import java.net.*; e6 x#4YH  
/e^) *r  
B3u/ y  
public class FileSplitterFetch extends Thread { ` aF8|tc_  
|@yYM-;6  
 ;Q4,I[?%  
String sURL; //File URL aDxNAfP  
long nStartPos; //File Snippet Start Position AXSip  
long nEndPos; //File Snippet End Position YRr,{[e  
int nThreadID; //Thread's ID 'mTY56Yq  
boolean bDownOver = false; //Downing is over \ym^~ Q|  
boolean bStop = false; //Stop identical MX7Ix{  
FileAccessI fileAccessI = null; //File Access interface .Dl ?a>I  
3EY m@oZj  
=5V7212  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException MI^$df  
{ r<Cr)%z!  
this.sURL = sURL; j(]O$""  
this.nStartPos = nStart; `wU['{=  
this.nEndPos = nEnd; 1#Hr{&2  
nThreadID = id; !E_|Zp]up  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qSG0TWD!pq  
} IYXN}M.=  
yjH'<  
0Q?%B6g$m[  
public void run() jYFmL_{  
{ t u{~:Z(  
while(nStartPos < nEndPos && !bStop) ?!/8~'xA6  
{ =Y6W Qf  
'5[(QM5Gi&  
47 Bg[  
try{ ,|>>z#Rr(n  
URL url = new URL(sURL); SK^(7Ws~0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R8eBIJ/@_  
httpConnection.setRequestProperty("User-Agent","NetFox"); Dq$1 j%4Y  
String sProperty = "bytes="+nStartPos+"-"; ~gGkw#  
httpConnection.setRequestProperty("RANGE",sProperty); }1~9i'o%Z  
Utility.log(sProperty); #N >66!/V  
"::2]3e  
6NhGTLI  
InputStream input = httpConnection.getInputStream(); %dq%+yw{%m  
//logResponseHead(httpConnection); F kf4R5Y?  
B)1(  
K[0z$T\  
byte[] b = new byte[1024]; D15-pz|Q  
int nRead; u a_w5o7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) g\@.qKF  
{ S.1>bs2  
nStartPos += fileAccessI.write(b,0,nRead); Ol+D"k~<C  
//if(nThreadID == 1) ]?wz.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hfyU}`]  
} !K}W.yv,  
`BG>%#  
qQG? k~r  
Utility.log("Thread " + nThreadID + " is over!"); ~u2f`67{  
bDownOver = true; n*na6rV\k  
//nPos = fileAccessI.write (b,0,nRead); fDfph7[)  
} a`#lYM%(>  
catch(Exception e){e.printStackTrace ();} `XK\', }F  
} l 'wu-  
} S7nx4c2xK~  
~D4l64  
Yk|.UuXT  
//打印回应的头信息 m*N8!1Ot  
public void logResponseHead(HttpURLConnection con) ~n%Lo3RiP  
{ ) 5$?e  
for(int i=1;;i++) ~+Pe=~a[  
{  JJ}DYv  
String header=con.getHeaderFieldKey(i); r hucBm  
if(header!=null) Og1vD5a  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $ B&Zn Z?  
Utility.log(header+" : "+con.getHeaderField(header)); EA8plQ~GtE  
else RtHai[j  
break; "0#(<zb|  
} >c<xy>N  
} UdM2!f  
./Ek+p*96H  
Rk#'^ }  
public void splitterStop() y2s(]# 8  
{ j=M%*`@  
bStop = true; BSg T 6K  
} ?2Z`xL9QT  
6Q]c}  
Z@&%"nO  
} tUc<ExvP,  
M."/"hV`-  
3x+=7Mg9  
/* 2sk7E'2(  
**FileAccess.java ``:[Jr &  
*//文件访问(定位,写) NQ 6oyg@&  
package NetFox; 1v`|mU}i,  
import java.io.*; E7? n'!=  
j<0 ;JAL  
ux(~+<k  
public class FileAccessI implements Serializable{  .nrbd#i-  
la-:"gKC  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *!&?Xy%\"j  
RandomAccessFile oSavedFile; ,pGA|ob  
long nPos; 4}/gV)  
S qb>a j  
#!UJY%c ~  
public FileAccessI() throws IOException q6C`hVM l  
{ z7`|N`$Z#s  
this("",0); -wV2 79^b  
} ov,s]g83  
h`N2M,  
xi "3NF%=  
public FileAccessI(String sName,long nPos) throws IOException z|%Pi J ,  
{ X5[t6q!  
oSavedFile = new RandomAccessFile(sName,"rw"); {x,)OgK!{  
this.nPos = nPos; 3Q=\W<Wu  
oSavedFile.seek(nPos); np6G~0Y`  
} 2v4K3O60G  
} f&=}  
Zf!Q4a"  
public synchronized int write(byte[] b,int nStart,int nLen) ,;w~ VZ4  
{ _&V,yp!|  
int n = -1; FVrB#Hw~  
try{ nf"#F@dk  
oSavedFile.write(b,nStart,nLen); +<[q"3  
n = nLen; tR'RB@kJ  
} M`'DD-Q  
catch(IOException e) 8Z9>h:c1  
{ 'ZMh<M[  
e.printStackTrace (); f7Nmvla[q  
} ?i#x13  
JXe~ 9/!  
ly*v|(S&  
return n; H(76sE  
} ]zJO)(d$>  
7UW\|r  
U.t][#<3  
} ]3I a>i  
! Ea!"}  
<af# C2`B  
/* ,v8e7T  
**SiteInfoBean.java |w*s:p  
*/ Fd<Ouyxqe  
package NetFox; mL`8COA  
,IboPh&Q78  
|LQ%sV  
public class SiteInfoBean { ]j/= x2p  
1[Yl8W%pj  
?|W3RK;  
private String sSiteURL; //Site's URL Bt@?l]Y  
private String sFilePath; //Saved File's Path zc)nDyn  
private String sFileName; //Saved File's Name _p0Yhju?  
private int nSplitter; //Count of Splited Downloading File Evm3Sm!S  
[=jZP,b&),  
ky[Cx!81C  
public SiteInfoBean() EDgtn)1  
{//nSplitter的缺省值为5 {*O+vtir%  
//default value of nSplitter is 5 Bv@p9 ] n  
this("","","",5); <H60rON  
} _yN5sLLyb  
$aJay]F  
t>}S@T{~T  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )$E){(Aa  
{ [}HPV+j=U  
sSiteURL= sURL; wQy~5+LE  
sFilePath = sPath; ,%IP27bPW  
sFileName = sName; dR\yRC]I  
this.nSplitter = nSpiltter; T]&?^QGAZ  
qF bj~ec  
:3Q:pKg  
} ` wEX;  
o;Z"I&  
1K@ieVc  
public String getSSiteURL() \os"w "  
{ 3<$Ek3X  
return sSiteURL; )yig=nn  
} @Drl5C}+  
SQK82 /  
8ly)G  
public void setSSiteURL(String value) K(u pz n*a  
{ fG>3gS6&  
sSiteURL = value; *Ts$Hj[  
} "QXnE^  
kK4 a;j.#  
>Df; 1:U  
public String getSFilePath() ]m 3cm  
{ hIqUidJod  
return sFilePath; N80ogio_Tk  
} AA,/AKikd  
ZJ2 MbV.6  
jnJ*e-AW  
public void setSFilePath(String value) (N&?Z]|yr  
{ iKPgiL~  
sFilePath = value; m\jjj^f a  
} @uRJl$3  
d5Ae67  
Gy):hGgN  
public String getSFileName() @,sjM]  
{ ^ fC2o%3^  
return sFileName; zKJQel5  
} <CO_JWD  
l59\Lo:  
Z9M$*Zp  
public void setSFileName(String value) )Hin{~h  
{ rMIX{K)'f  
sFileName = value; [UzacXt  
} B6IKD  
nm<VcCc  
"A Bt  
public int getNSplitter() FvVC 2Z  
{ =Y|( }92  
return nSplitter; C=&n1/  
} NYHK>u/5c  
P A ZjA0d  
g4,ldr"D  
public void setNSplitter(int nCount) 8=Oym~  
{ n^{h@u  
nSplitter = nCount; n5"oXpcIx  
} J7",fb  
} u4 es8"  
1\@PrO35J  
qZ[HILh!  
/* fTR6]i;  
**Utility.java 6:%lxG  
*/ )ddJ\:  
package NetFox; s/hWhaS<  
l+2NA4s  
P]^OSPRg  
public class Utility { !Q~>)$Cf^  
b6k_u9m^E  
@R`6j S_gK  
public Utility() ;Z0&sFm  
{ O0'|\:my  
O6?{@l  
SN{A@dyt  
} '/UT0{2;rS  
UVl B=  
//线程睡眠 ,h1\PT9ULY  
public static void sleep(int nSecond) ~xY"P)(x;  
{ zOSUYn  
try{ 1QA/ !2E  
Thread.sleep(nSecond); o>(<:^x9  
} [N~7PNdS  
catch(Exception e) #'KM$l,P  
{ `qmwAT  
e.printStackTrace (); 6 L4\UT r  
} <?IDCOt ?  
} %E@o8  
c.LRS$o/j  
//日志 /dg?6XT/  
public static void log(String sMsg) Rkk`+0K7$J  
{ j~\FDcG*ed  
System.err.println(sMsg); H?;+C/-K`_  
} dpS@:  
]8}2  
ws`r\k]3J  
public static void log(int sMsg) x7E] }h  
{ AKjobA#  
System.err.println(sMsg); /f?;,CyI  
} #FAW@6QG  
} 6P >Y2xV:  
(Q||5  
ejR$N!LL  
/* +-;v+{  
**TestMethod.java 2"a%%fv  
*/ l]&A5tz3  
package NetFox; 3 $%#n*  
w)S 4Xi=  
Lct_6?  
public class TestMethod { ec#`9w$  
 gh[q*%#  
3O*iv{-&  
public TestMethod() *>qc6d@'  
{ ///xx/weblogic60b2_win.exe Z ;~%!  
try{ viU}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); B=>Xr!pM!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); r]xN&Ne5Q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N9d^;6;i  
fileFetch.start(); [-l>f P0  
} }03?eWk/y  
catch(Exception e){e.printStackTrace ();} <!G /&T  
sdCG}..`  
V}<<?_  
} :,p3&2 I  
3v3cK1K@oE  
7^rT-f07  
public static void main(String[] args) @eBo7#Zr  
{ @6DKw;Q  
new TestMethod(); |b='DJz2  
} bt1bTo  
} L=Aj+  
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