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http断点续传简单实现(java)

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/* VlL%dN; 0  
**SiteFileFetch.java *TI?tD  
*/ y:Of~ ]9@  
package NetFox; z5~W >r  
import java.io.*; lQ!OD& 6  
import java.net.*; Su? cC/  
yf8kBT:&S  
`=,emP&(H&  
public class SiteFileFetch extends Thread { wD{c$TJ?{F  
Xxd]j]  
|KS,k|).  
SiteInfoBean siteInfoBean = null; //文件信息Bean `JPkho  
long[] nStartPos; //开始位置 )7 8T+7Kq  
long[] nEndPos; //结束位置 NV9JMB{q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6'@{ * u  
long nFileLength; //文件长度 3/Z>W|w#w  
boolean bFirst = true; //是否第一次取文件 'x"(OdM:[  
boolean bStop = false; //停止标志 ~gMt U  
File tmpFile; //文件下载的临时信息 Hk h'h"_r  
DataOutputStream output; //输出到文件的输出流 S7PWP< 9  
8,!Oup  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Yb/*2iWX  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~ ) w4Tq  
{ xb9+-{<J  
siteInfoBean = bean; T :m" eD;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); IVxZ.5:L$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); u5glKE  
if(tmpFile.exists ()) cY_ke  
{ p@4GI[4  
bFirst = false; 5~:/%+F0=  
read_nPos(); ) =29Hm"  
} 'EXx'z;/#  
else fC*cqc~{@  
{ A0k?$ko  
nStartPos = new long[bean.getNSplitter()]; 7>F{.\Z  
nEndPos = new long[bean.getNSplitter()]; 8j3Y&m4^  
} zB`woI28  
A!x&,<  
G--X)h-  
m Jk\$/Kh  
} g""GQeR  
-YKy"   
z^Ikb(KC  
public void run() $Emu*'  
{  L1 /`/  
//获得文件长度 .\^0RyJE  
//分割文件 _J W|3q  
//实例FileSplitterFetch W_Y8)KxG:L  
//启动FileSplitterFetch线程 8iJB'#''*  
//等待子线程返回  xV5UaD<  
try{ 4<F z![>  
if(bFirst) 4.jRTL5-oj  
{ F1L[3D^-  
nFileLength = getFileSize(); "yaxHd  
if(nFileLength == -1) AT~,  
{ i!?gga  
System.err.println("File Length is not known!"); \{lv~I  
} "/i$_vl  
else if(nFileLength == -2) ~dRstH7u  
{ SE]5cJ'>  
System.err.println("File is not access!"); 8v& \F  
} qM(}|fMbN  
else 1I9v`eT4  
{ /^BC Qaj  
for(int i=0;i<nStartPos.length;i++) k5.5$<< T  
{ 2Kz+COP+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P#~B @d  
} +&`W\?.~  
for(int i=0;i<nEndPos.length-1;i++) \%=\4%:  
{ 1jl !VU6  
nEndPos = nStartPos[i+1]; :;7I_tb  
} G-Tmk7m  
nEndPos[nEndPos.length-1] = nFileLength; St-uE |8  
} XWp8[Cx s  
} ~hLan&T  
H0Pxw P>q  
lrT2*$ w3  
//启动子线程 6@J=n@J$p  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `@h|+`h  
for(int i=0;i<nStartPos.length;i++) 7w/IHML  
{ &[.`xZ(|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v~P,OP("c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), jV3PTU  
nStartPos,nEndPos,i); I#M3cI!X?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A IP~A]T  
fileSplitterFetch.start(); `a& kD|Yh  
} Cl}nP UoL  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1PkCWRpR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); iEr,ly  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @!#e\tx  
nEndPos = " + nFileLength); 9Yx(u 2PQ  
// fileSplitterFetch[nPos.length-1].start(); 0CrsZtX  
V)`2 Kw  
B[t^u\Fk  
//等待子线程结束 $<^t][{  
//int count = 0; C9 n%!()>  
//是否结束while循环 ,S8K!  
boolean breakWhile = false; H/f}t w  
C&q}&=3r  
&WCVdZK:  
while(!bStop) YTgT2w  
{ qHrIs-NR  
write_nPos(); ;8F6a:\v  
Utility.sleep(500); wQ-BY"cK\  
breakWhile = true; -vT$UP  
KJn 3&7  
M#o=.,  
for(int i=0;i<nStartPos.length;i++) C#&b`  
{ _ru<1n[4~  
if(!fileSplitterFetch.bDownOver) z:n JN%Qb  
{ 1_~'?'&^  
breakWhile = false; 4pDZ +}p  
break; p<VW;1bt5  
} e mq%" ;.  
} aBF<it>  
if(breakWhile) X bV?=  
break; d[(%5pw~zL  
Erl@] P4  
Tq6@ 1j6p  
//count++; ^w RD|  
//if(count>4) "MT{t><  
// siteStop(); ht)KS9Xu  
} =2wy;@f  
i];@e]   
P[cGCmM  
System.err.println("文件下载结束!"); RG_)<U/B  
} I'cM\^/h  
catch(Exception e){e.printStackTrace ();} '$OLU[(Y  
} `^E(P1oJ3  
PI" )^`  
s&OwVQ<M  
//获得文件长度 Y wM;G g3  
public long getFileSize() =>h~<88#5  
{ |}roR{gc|  
int nFileLength = -1; W/R-~C e  
try{ p&\x*~6u  
URL url = new URL(siteInfoBean.getSSiteURL()); |c>A3 P$=B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q ?W6  
httpConnection.setRequestProperty("User-Agent","NetFox"); jZY9Lx8o  
>^Z!  
W,n0'";')  
int responseCode=httpConnection.getResponseCode(); 0:Lm=9o  
if(responseCode>=400) QPa&kl  
{ &"svt2  
processErrorCode(responseCode); ?G-a:'1!6  
return -2; //-2 represent access is error \oGZM0j  
} *o[*,1Pw  
[ !:.9  
5B( r[Ni b  
String sHeader; STB=#z  
^Sr`)vP  
{Z|.-~W  
for(int i=1;;i++) e~we YGK  
{ akQtre`5sd  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3C8'@-U  
//Utility.log(in.readLine()); ji2if.t@  
sHeader=httpConnection.getHeaderFieldKey(i); #H1yjJQ /x  
if(sHeader!=null) A! 1>  
{ GRj{*zs  
if(sHeader.equals("Content-Length")) 'gE_xn7j  
{ 6i \b&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 413r3/  
break; Nr7MSFiL  
} &e% y|{Y  
} QTK{JZf  
else A\.M/)Qo  
break; uBs[[9je(  
} ?P`]^#  
} ?(U> )SvF  
catch(IOException e){e.printStackTrace ();} Oy[t}*Ik  
catch(Exception e){e.printStackTrace ();} <  v_?}  
^QV;[ha,o  
}`  
Utility.log(nFileLength); q^dI!93n|  
<H E'5b  
mrd(\&EhA  
return nFileLength; ( {zp$P}  
}  Jb {m  
Cl>'K*$F  
}kXF*cVg  
//保存下载信息(文件指针位置) FAU^(]-5m  
private void write_nPos() x_(B7ob  
{ *Xl&N- 04  
try{ I[<C)IG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]Wv\$JXI  
output.writeInt(nStartPos.length); fX} dh9  
for(int i=0;i<nStartPos.length;i++) JYKA@sZHe  
{ 'n.eCd j  
// output.writeLong(nPos); wTIOCj  
output.writeLong(fileSplitterFetch.nStartPos); HcQ{ok9u  
output.writeLong(fileSplitterFetch.nEndPos); 18ci-W#p  
} eB!0:nHN  
output.close(); %t%+;(M9  
} S <|e/![@  
catch(IOException e){e.printStackTrace ();} |'=R`@w~0  
catch(Exception e){e.printStackTrace ();} d:=5y)  
} )BS./zD*[<  
^i#q{@g  
WZ"x\K-;  
//读取保存的下载信息(文件指针位置) 3Xf}vdgdM$  
private void read_nPos() PGu6hV{  
{ `Nu3s<O7CF  
try{ = ?T'@C  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Scs \nF2  
int nCount = input.readInt(); ;9 XM s)  
nStartPos = new long[nCount]; s'fHh G6  
nEndPos = new long[nCount]; 0sk*A0HX-  
for(int i=0;i<nStartPos.length;i++) i v&:X3iB  
{ _i6G)u&N  
nStartPos = input.readLong(); d^WVWk K  
nEndPos = input.readLong(); &kRkOjuk  
} .v0.wG  
input.close(); =R?NOWrDY  
} *V3}L Z  
catch(IOException e){e.printStackTrace ();} p^7ZFUP  
catch(Exception e){e.printStackTrace ();} ix$?/GlL  
} JTQ$p*2]  
SpjL\ p0  
E,u@,= j  
private void processErrorCode(int nErrorCode) R.*KaCA  
{ B.;/N220P  
System.err.println("Error Code : " + nErrorCode); '1|r+(q|2  
} #: w/vk  
=MRg  
d1D{wZ3g  
//停止文件下载 NHPpHY3^.  
public void siteStop() u==bLl=$  
{ }*hY#jo1  
bStop = true; X'IW &^kI  
for(int i=0;i<nStartPos.length;i++) >QU1_'1r  
fileSplitterFetch.splitterStop(); ~z^VMr  
|Ah26<&  
h~urZXD<  
} <hkg~4EKc  
} a7)q^;:O  
//负责部分文件的抓取 8AOJ'~$  
**FileSplitterFetch.java r,A750P^  
*/ ;mu9;ixZ  
package NetFox; 8h78Zb&[  
5<<e_n.2q  
kZBIXW,G  
import java.io.*; w6'o<=  
import java.net.*; iXqc$!lTH  
S92'\2  
iKu[j)F  
public class FileSplitterFetch extends Thread { `f}}z5  
z%Op_Ddp  
:G?"BL5vP  
String sURL; //File URL & %ej=O  
long nStartPos; //File Snippet Start Position cmmH)6c>  
long nEndPos; //File Snippet End Position jX$TiG  
int nThreadID; //Thread's ID :=UiEDN@  
boolean bDownOver = false; //Downing is over 5][Rvu0  
boolean bStop = false; //Stop identical l[.*X  
FileAccessI fileAccessI = null; //File Access interface aEW Z*y  
L~cswG'K  
is}o5\JEL  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException R4"["T+L`  
{ ~Us1F=i_Q  
this.sURL = sURL; 9 %4Pt=v~d  
this.nStartPos = nStart; kzZtKN9Az  
this.nEndPos = nEnd; `zAV#   
nThreadID = id; zO<EbqNe!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 D9B?9Qt2[  
} :c"J$wT/  
I1=YSi;A  
m0t 5oO  
public void run() 2lDgv ug  
{ [aU#"k)M  
while(nStartPos < nEndPos && !bStop) S3PW[R@=  
{ W1f]A#t<  
f(=yC} si  
j_-$xz5-  
try{ ;LELC5[*s  
URL url = new URL(sURL); c5>&~^~>Tx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -N(y+~wN  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9aD6mp  
String sProperty = "bytes="+nStartPos+"-"; 9Xmb_@7b}  
httpConnection.setRequestProperty("RANGE",sProperty); oJVpNE[3]  
Utility.log(sProperty); O?p.kf{b  
 N c F  
)p4o4 aM  
InputStream input = httpConnection.getInputStream(); >Y?B(I2e  
//logResponseHead(httpConnection); 2GLq#")P  
3M8P%  
?q1&(g]qO  
byte[] b = new byte[1024]; "\Jq2vM  
int nRead; ndT:,"s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Wxkk^J9F3  
{ E&}r"rbI  
nStartPos += fileAccessI.write(b,0,nRead); EC&t+"=R  
//if(nThreadID == 1) #s{>v$F  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Za}*6N=?*  
} "Y }f"X|  
Q4{%)}2$  
GeWB"(t  
Utility.log("Thread " + nThreadID + " is over!"); @xH|(  
bDownOver = true; {J%Na&D  
//nPos = fileAccessI.write (b,0,nRead); 4,tMaQ  
} nS"K dPM  
catch(Exception e){e.printStackTrace ();} 9*GwW&M%1_  
} J?)vsnD.H  
} (l{+ T#  
D{Y~ kV|  
8 Mp2MZ*p  
//打印回应的头信息 J0a]Wz%  
public void logResponseHead(HttpURLConnection con) eJ +;!0  
{ ?{?mAb c  
for(int i=1;;i++) I.r &;   
{ gP/[=:  
String header=con.getHeaderFieldKey(i); ~fI&F|  
if(header!=null) D$q"k"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); FXV=D_G}  
Utility.log(header+" : "+con.getHeaderField(header)); A^q= :ofQ  
else Vo+d3  
break; .3?'+KZ,  
} z{pNQ[t1Z  
} '!Ps4ZTn_  
j|FGb:  
7J~6J .m  
public void splitterStop() =rl/ l8|P  
{ Fx4C]S  
bStop = true; nT` NfN  
} m?'5*\(ST  
FH)bE#4  
L Tp5T|O  
} WGN[`D"  
)wP0U{7?v  
o m`r^3,  
/* cBmo#:>'  
**FileAccess.java W=5+k0Q  
*//文件访问(定位,写) daaUC  
package NetFox; }U7>_b2  
import java.io.*; 2n?\tOm(V  
[P OcO  
fpM 4q  
public class FileAccessI implements Serializable{ -?e~dLu  
)~_!u}+:(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V:6#IL  
RandomAccessFile oSavedFile; l"}W $3]u$  
long nPos; D4s*J21)D  
(sS[F-2R7  
reM%GU  
public FileAccessI() throws IOException idGkX ?  
{ {5.,gb@6  
this("",0); _E)xR  
} .Y_RI&B!L  
86/CA[Y-  
\>cZ=  
public FileAccessI(String sName,long nPos) throws IOException TMKemci  
{ hOfd<k\A  
oSavedFile = new RandomAccessFile(sName,"rw"); 9Vzk:zOT  
this.nPos = nPos; ]WN{8   
oSavedFile.seek(nPos); X^_,`H@  
} qw%4j9}  
3=t}py7M  
L]9!-E  
public synchronized int write(byte[] b,int nStart,int nLen) 8Qu7x[tK?  
{ IL3,dad'^  
int n = -1; GK95=?f~8;  
try{ T fzad2}^  
oSavedFile.write(b,nStart,nLen); i= ~HXr}  
n = nLen; CEYHD?9k8  
} L$ ]D&f8:  
catch(IOException e) RK'3b/T  
{ v6s8 p  
e.printStackTrace (); hx)Ed  
} K_]LK  
eX?o 4>  
Q;m .m2  
return n; {zbH.V[  
} o"Ef>5N  
}xLwv=Ia  
Mu Z\<;W$  
} {nryAXK  
l-t:7`=|  
bRNE:))r_  
/* 2(\>PN-  
**SiteInfoBean.java deHBY4@  
*/ l,6="5t  
package NetFox; U%gP2]t%cs  
UY}lJHp0  
S`0@fieOf  
public class SiteInfoBean { He#+zE ;  
Oq+C<}eg  
akd~Z  
private String sSiteURL; //Site's URL T]CvfvO5  
private String sFilePath; //Saved File's Path Kwh3SU=L}  
private String sFileName; //Saved File's Name *ZN"+ wf\  
private int nSplitter; //Count of Splited Downloading File 6K`frt  
K<|b>PI.s  
m?[F)<~a  
public SiteInfoBean() JG/sKOlA  
{//nSplitter的缺省值为5 Dm 'Q&  
//default value of nSplitter is 5 tp5]n`3rD  
this("","","",5); !29 Rl`9  
} D#(A?oN  
4+v~{  
.YS[Md{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) c (\-7*En  
{ HO' ELiZ_q  
sSiteURL= sURL; 7F+f6(hB  
sFilePath = sPath; cG"jrQ  
sFileName = sName; D;Az>]>q  
this.nSplitter = nSpiltter; WU=Os8gR  
0CTI=<;  
{Ziq~{W_  
} W9eR3q  
zaoZCyJT%  
1 #EmZ{*  
public String getSSiteURL() Ui?t@.  
{ {?5EOp~  
return sSiteURL; apw8wL2  
} dX+DE(y  
ss,6;wfX  
Yt|{l  
public void setSSiteURL(String value) ={zYcVI  
{ ?dxhe7m  
sSiteURL = value; [0J0<JnK  
} 56TUh_  
(F_#LeJ|  
!sR`]0  
public String getSFilePath() 2OK%eVba  
{ XqJ@NgsY  
return sFilePath; 6'qs=Ql  
} :T'"%_d5  
6J&L5E  
4|Z3;;%+  
public void setSFilePath(String value) <Pf W  
{ '9^x"U9c  
sFilePath = value; ~~yo& ]  
} E-! `6  
MNJ$/l)h  
fmloh1{4  
public String getSFileName() wt)tLMEv  
{ :r#FI".qx  
return sFileName; ,T1 t`  
} N^`F_R1Z  
k6*2= xK~  
]2Lwd@  
public void setSFileName(String value) ~Jq<FVK  
{ uWMAXGL  
sFileName = value; 8|i&Gbw+  
} *+Q,b^N  
U24?+/5D]  
QEtZ]p1H@  
public int getNSplitter() 4pA(.<#A  
{ [nflQW6  
return nSplitter; JY%c<  
} c: #1Aym  
!&19%C4  
qY0GeE>N  
public void setNSplitter(int nCount) )!M:=}."  
{ 4d6F4G4U  
nSplitter = nCount; @gs Kb* ,  
} FtE%<QHt  
} (MbI8B>  
*S{%+1F  
6)DYQ^4y  
/* z!t &zkAK  
**Utility.java Z&/;6[  
*/ VN;Sz,1Z  
package NetFox; [\. ho9  
Q0nSOTQ  
rX fQ_  
public class Utility { hv7!x=?8  
knF *~O :y  
:9K5zD  
public Utility() 9j9A'Y9(  
{ ~@L$}Eu  
QbpRSdxy`$  
<W\~A$  
} k(hes3JV  
GQ)hZt0  
//线程睡眠 DA[-( s  
public static void sleep(int nSecond) ?u 9) GJO[  
{ #!9aTp).AL  
try{ TvMY\e  
Thread.sleep(nSecond); I)DLnnQQ  
} 4$ejJaE  
catch(Exception e) _Z5l Nu  
{ j}S  
e.printStackTrace (); v@"xEf1n[  
} h^34{pKDn  
} ^|as]x!sv  
jlzqa7  
//日志 *F~"4g  
public static void log(String sMsg) )"|g&=  
{ uXu'I  
System.err.println(sMsg); 0qZ{:}`3  
} -4Y}Y5 9\  
wxr93$v  
QQ1+uY  
public static void log(int sMsg) #.a4}ya19  
{ NfS0yQPx  
System.err.println(sMsg); BI,K?D&W-  
} rWi9'6  
} Xp._B4g  
B>#zrCD  
u ldea)  
/* BP*gnXj  
**TestMethod.java M)Tv(7  
*/ ~>xn9vb=  
package NetFox; % NX  
44RZk|U1J{  
2%1 g%  
public class TestMethod { ;^O^&<  
 QH9(l  
htlsU*x  
public TestMethod() M1Od%nz3  
{ ///xx/weblogic60b2_win.exe (Qq! u  
try{ E=sBcb/v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); RAXqRP,iw  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); pRUN [[L  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0%`\ 8  
fileFetch.start(); A{mbL2AxwC  
} DU]MMR  
catch(Exception e){e.printStackTrace ();} w0^(jMQe^  
X f!Bsp#\g  
k[y{&f,  
} 1Qhx$If~  
UQ`%,D  
ch \*/  
public static void main(String[] args) |3Oe2qb  
{ }9<aX Y,  
new TestMethod(); T* -*U /  
} 3`IDm5  
} vlp]!7v  
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