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http断点续传简单实现(java)

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/* VFZ_Vw  
**SiteFileFetch.java bN6FhKg|  
*/ cI9}YSk  
package NetFox; ~v 2E<S3  
import java.io.*; /mb?C/CI  
import java.net.*; ;$Eg4uX  
@w)Vt $+b]  
<_S>-;by  
public class SiteFileFetch extends Thread { 0i[,`>-Av  
,Qgxf';+$  
>Jl(9)e  
SiteInfoBean siteInfoBean = null; //文件信息Bean Ix;9D'^}  
long[] nStartPos; //开始位置 W?5u O  
long[] nEndPos; //结束位置 N{}XHA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f_*Bd.@  
long nFileLength; //文件长度 ~Bll\3-=  
boolean bFirst = true; //是否第一次取文件 K[%)_KW  
boolean bStop = false; //停止标志 ,DN>aEu1  
File tmpFile; //文件下载的临时信息 : GZx-  
DataOutputStream output; //输出到文件的输出流 ?N 6'*2{NT  
v'"0Ya  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 73kF=*m  
public SiteFileFetch(SiteInfoBean bean) throws IOException < p<J;@  
{ |fx*F}1  
siteInfoBean = bean; 87Sqs1>cw  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); cr{;gP  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +ht -Bl  
if(tmpFile.exists ()) 9'tElpDJ6#  
{ o1j_5c PS  
bFirst = false; CzF#feTA  
read_nPos(); s3+^q  
} .^<4]  
else wic& $p/%  
{ }n+#o!uEf  
nStartPos = new long[bean.getNSplitter()]; 6]=$c<.&  
nEndPos = new long[bean.getNSplitter()]; vZHm'  
} de?Bn+mvi.  
SjT8 eH #  
3d qj:4[f  
,k*g `OTW  
} Hshm;\'  
tpJe1J<  
wHSas[4k  
public void run() l-Hp^|3Wq  
{ 1LbJR'}  
//获得文件长度 T)"B35  
//分割文件 }H!l@  
//实例FileSplitterFetch T}ZUw;}BL  
//启动FileSplitterFetch线程 i1qhe?5  
//等待子线程返回 1}A1P&2>  
try{ I`?6>Z+%)  
if(bFirst) TA=VfA B  
{ <P)vx  
nFileLength = getFileSize(); K,7IBv,B[  
if(nFileLength == -1) /8\gT(@  
{ xef@-%mcoy  
System.err.println("File Length is not known!"); 50 :gk*hy  
} ;aJBx  
else if(nFileLength == -2) nE!h&}(  
{ (nWi9(}J  
System.err.println("File is not access!"); A.a UWh  
} y^vB_[6l  
else -nbo[K  
{ J. ;9-  
for(int i=0;i<nStartPos.length;i++) :wn9bCom?M  
{ f%Y'7~9bA  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9%>GOY  
} xEt".K  
for(int i=0;i<nEndPos.length-1;i++) l6^IX0&p  
{ f; <qGM.#|  
nEndPos = nStartPos[i+1]; 4{?Djnh  
} 3g!tk9InG  
nEndPos[nEndPos.length-1] = nFileLength; UADD 7d  
} oe<9CK:?>  
} :J|t! `  
F ] e]  
=-XI)JV#  
//启动子线程 0{0|M8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ')k n  
for(int i=0;i<nStartPos.length;i++) o1x IGP<  
{ Tw|cgB  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3<ikMUq&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7B@[`>5?%L  
nStartPos,nEndPos,i); 1'c  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0_d,sC?V  
fileSplitterFetch.start(); )/BI :)  
} `N8?F3>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NwH`t#zd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s8,{8k  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", YGRv``(  
nEndPos = " + nFileLength); ][b_l(r$?  
// fileSplitterFetch[nPos.length-1].start(); !a"RHg:HO  
0^l|W|.Z  
Tx)X\&ij&  
//等待子线程结束 %d<uOCf\Q  
//int count = 0; Bvke@|]kW  
//是否结束while循环 F!FXZht$P  
boolean breakWhile = false; 1bW[RK;GE  
=|)W#x9=  
2&st/y(hs  
while(!bStop) %#!pAUP\&  
{ F9DY\EI  
write_nPos(); 9[<,49  
Utility.sleep(500); }co v"o  
breakWhile = true; 6\MH2&L<  
YzTmXwuA5  
+8tdAw  
for(int i=0;i<nStartPos.length;i++) g. V6:>,  
{ mez )G|  
if(!fileSplitterFetch.bDownOver) E^uWlUb{  
{ !+qy~h  
breakWhile = false; h,:8TMJRRN  
break; de.!~%D  
} uWs5 +  
} 8*sZ/N.  
if(breakWhile) y'ZRoakz)  
break; h^{D "  
Z)RoFD1]C  
%O$4da"y  
//count++; &&Sl0(6x[T  
//if(count>4) bERYC|  
// siteStop(); ^j"*-)R  
}  yQkj4v{  
dA;f`Bi;Q  
q&.SB`  
System.err.println("文件下载结束!"); yqdh LX|Mk  
} 7x *]  
catch(Exception e){e.printStackTrace ();} !<psK[  
} o<\CA[   
TCW[;d  
. }QR~IR'  
//获得文件长度 gAcXd<a0  
public long getFileSize() X@$x(Zc  
{ jl# )CEx  
int nFileLength = -1; Yb57Xu  
try{ AL #w  
URL url = new URL(siteInfoBean.getSSiteURL()); Rk#@{_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F1skI _!  
httpConnection.setRequestProperty("User-Agent","NetFox"); *KF-q?PBb  
0QE2e'}}-  
n@9*>D U  
int responseCode=httpConnection.getResponseCode(); E 9=a+l9  
if(responseCode>=400) xngK_n  
{ $_N<! h*\  
processErrorCode(responseCode); 1:I47/  
return -2; //-2 represent access is error Y<X,(\iEHP  
} l`s_Id#  
9Ra_[1  
n !ty\E  
String sHeader; L_Q1:nL-0  
X|Gsf= 1S  
e<_p\LiOS  
for(int i=1;;i++) ocwh*t)<k  
{ Eeem y*U  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vAW+ ,Rfj  
//Utility.log(in.readLine()); _KSYt32N  
sHeader=httpConnection.getHeaderFieldKey(i); N :E7rtT,M  
if(sHeader!=null) &r \pQ};  
{ VH3 j  
if(sHeader.equals("Content-Length")) fL[(;KcAa  
{ n GE3O#fv  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8+ 5-7)  
break; we6']iaV  
} b<UZD yN~  
} ]ee%=+'  
else gie}k)&M  
break; X9^a:7(  
} &M$s@FUY  
} O9>& E;`5  
catch(IOException e){e.printStackTrace ();} t\2Lo7[Pu  
catch(Exception e){e.printStackTrace ();} 1n7tmRl  
qV57P6<  
x%kS:!  
Utility.log(nFileLength); $j(2M?.>#  
q.L0rY!  
#S+GI!  
return nFileLength; Z_&6 <1,H  
} " $5J7  
y>zPsc,  
%zg&eFRHI  
//保存下载信息(文件指针位置) 31b9pi}nf  
private void write_nPos() /JPyADi  
{ 0w?\KHT  
try{ 't3/< h<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); YKbR#DC\  
output.writeInt(nStartPos.length); ;5 W|#{I  
for(int i=0;i<nStartPos.length;i++) a%Ky;ys  
{ &f1dCL%z7  
// output.writeLong(nPos); d, j"8\@  
output.writeLong(fileSplitterFetch.nStartPos); $0rSb0[  
output.writeLong(fileSplitterFetch.nEndPos); A!}Wpw%(/  
}  :~JgB  
output.close(); \N1 G5W  
} (Sc]dH  
catch(IOException e){e.printStackTrace ();} )ymd#?wq  
catch(Exception e){e.printStackTrace ();} JCNZtWF  
} kb>:M.  
Yv!%Is  
6AgevyVG  
//读取保存的下载信息(文件指针位置) BwO^F^Pr?k  
private void read_nPos() h amn9  
{ <6k5nEh  
try{  ol^J-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); P@LYa_UFsN  
int nCount = input.readInt(); 56(S[  
nStartPos = new long[nCount]; XBv:$F.>$  
nEndPos = new long[nCount]; M/ @1;a@\  
for(int i=0;i<nStartPos.length;i++) Nq>74q]}n8  
{ Ct[{>asun  
nStartPos = input.readLong(); xcO Si>  
nEndPos = input.readLong(); m_~!Lj[u.  
} :Mr_/t2(  
input.close(); xk=5q|u_-  
} r=[T5,L(s  
catch(IOException e){e.printStackTrace ();} T1ZAw'6(K  
catch(Exception e){e.printStackTrace ();} wPTXRq%  
} 9j458Yd4*  
tiJY$YqA  
MH|!tkW>:  
private void processErrorCode(int nErrorCode) )24r^21.q  
{ `mV&[`NZ  
System.err.println("Error Code : " + nErrorCode); +5(#~  
} B5"(NJ;  
!%n3_tZC  
|<&9_Aq_  
//停止文件下载 ,yW BO  
public void siteStop() w4Nm4To  
{ [h7nOUL!  
bStop = true; C Sx V^  
for(int i=0;i<nStartPos.length;i++) U1<EAGo|  
fileSplitterFetch.splitterStop(); ]v7f9MC'\  
+ZeHZjd  
'Dyt"wfo  
} ?<c)r~9]  
} } y@pAeS,  
//负责部分文件的抓取 8"R; axeD  
**FileSplitterFetch.java 1t{h)fwi  
*/ e_6VPVa  
package NetFox; t-gg,ttnA  
p b:mw$XQ7  
zSMN k AM  
import java.io.*; Ndq|Hkd  
import java.net.*; ML?%s`   
?qwTOi  
cA_77#<8  
public class FileSplitterFetch extends Thread { V,?i]q;5  
{Lu-!}\NP  
`MFw2nu@t  
String sURL; //File URL :JW!$?s8H  
long nStartPos; //File Snippet Start Position B:dk>$>uQ  
long nEndPos; //File Snippet End Position ! 9B| `  
int nThreadID; //Thread's ID [80jG+6  
boolean bDownOver = false; //Downing is over 9dl\`zlA*  
boolean bStop = false; //Stop identical -?gr3rV@  
FileAccessI fileAccessI = null; //File Access interface lNuZg9h  
s"b()JP  
Z_{`$nW  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1qXqQA  
{ ^Nl)ocHv!  
this.sURL = sURL; *x3";%o  
this.nStartPos = nStart; $PA=7`\MP/  
this.nEndPos = nEnd; ;Hr FPx&d1  
nThreadID = id; |UvM [A|+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /Y:1zLs%  
} p.,o@GcL~  
qUX   
L|4kv  
public void run() !HyPe"`oL  
{ 6@kKr  
while(nStartPos < nEndPos && !bStop) 4Eh 2sI  
{ ?eD,\G  
5^lroC-(x  
j&n][=PL  
try{ vq yR aaMf  
URL url = new URL(sURL); ~_v?M%5i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |&vQ1o|}  
httpConnection.setRequestProperty("User-Agent","NetFox"); | _/D-m*  
String sProperty = "bytes="+nStartPos+"-"; [V'3/#Z  
httpConnection.setRequestProperty("RANGE",sProperty); tpw0j CVu  
Utility.log(sProperty); &>kklP  
a86m?)-c  
FtbqZN[  
InputStream input = httpConnection.getInputStream(); \,jrug<C$^  
//logResponseHead(httpConnection); j.O7-t%C  
T;D`=p#  
$P#Cf&R  
byte[] b = new byte[1024]; WK5~"aw  
int nRead; 6kH47Yc?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F?=(4Pyvu  
{ V*P3C5 l  
nStartPos += fileAccessI.write(b,0,nRead); 7e$\|~<  
//if(nThreadID == 1) (3YqM7cqt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F#S^Q`  
}  qGG  
J{8_4s!Xt>  
yIC.Jm D*  
Utility.log("Thread " + nThreadID + " is over!"); R=ddQ:W6g  
bDownOver = true; P~n I6/r1  
//nPos = fileAccessI.write (b,0,nRead); ]eA<  
} ( XYYbP  
catch(Exception e){e.printStackTrace ();} @a,X{ 0  
} `c@KlL*!Q  
} ^/`:o}7K7  
J5Rr7=:*S  
DE3>F^ j  
//打印回应的头信息 [oN}zZP]  
public void logResponseHead(HttpURLConnection con) K|$Dnma^n  
{ ^)=c74;;  
for(int i=1;;i++) ]UyIp`nV;  
{ ?Pz:H/ $  
String header=con.getHeaderFieldKey(i); l/[0N@r~  
if(header!=null) %jEdgD%xV  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }5dYmny  
Utility.log(header+" : "+con.getHeaderField(header)); QW :-q(s  
else SrzlR)  
break; a x1  
} U1(<1eTyu  
} (9q61z A  
.lrI|BH?z  
W,Q"?(+]B  
public void splitterStop() AP.WTFf  
{ %0 (,f  
bStop = true; j~!0n[F  
} 3c] oU1GfF  
.zr2!}lB  
\wRbhN  
} wWm 1G)  
=mV1jGqX  
8XtZF,Du  
/* =1 g  
**FileAccess.java q:Gi Qk-  
*//文件访问(定位,写) ^44AE5TO  
package NetFox; =KJK'1m9  
import java.io.*; w^N xR,  
`btw*{.[  
vH_QSx;C#  
public class FileAccessI implements Serializable{ nW2 fB8yq  
[B3qZ"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K~**. NF-n  
RandomAccessFile oSavedFile; D*3\4=6x  
long nPos; *44^M{ti<  
l]R O'  
01Bs7@"+  
public FileAccessI() throws IOException ,aS6|~ac4  
{ u )+;(Vd  
this("",0); >-rDBk ;K  
} )M(;:#le  
v,w/g|  
'J~{8w,.  
public FileAccessI(String sName,long nPos) throws IOException C;2!c  
{ O-- "\4  
oSavedFile = new RandomAccessFile(sName,"rw"); ?H8w/{J   
this.nPos = nPos; Dg~r%F  
oSavedFile.seek(nPos); gaBt;@?:Q  
} -;=0dfC(  
tWL3F?wd  
\/,54c2  
public synchronized int write(byte[] b,int nStart,int nLen) Q" BIk =  
{ 8 PI>Q  
int n = -1; nWpqAb  
try{ /h'V1zL#  
oSavedFile.write(b,nStart,nLen); =N,9#o6^  
n = nLen; xe}d&  
} [)U|HnAJ  
catch(IOException e) ~PYMtg=i  
{ 5D0O.v  
e.printStackTrace (); `Q?rQ3A}  
} S'T&`"Mr  
Cv{>|g#  
0g% `L_e_  
return n; B6&PYMFK?*  
} ^qXc%hjg  
'5zolp%St  
oiYI$ql3L  
} fR<_4L  
>?K@zsv}  
F VBuCi?W  
/* " O1\]"j  
**SiteInfoBean.java "w ] Bq0  
*/ R,[ dEP  
package NetFox; lN$#lyy  
Dd8*1,  
$p@V1"x  
public class SiteInfoBean { 6|gC##T  
@,0W(  
W/COrgbW  
private String sSiteURL; //Site's URL LwIl2u*  
private String sFilePath; //Saved File's Path ?)<DEu:Y  
private String sFileName; //Saved File's Name ^(7<L<H  
private int nSplitter; //Count of Splited Downloading File !4zSE,1  
Dz$GPA   
U{(B)dFTH  
public SiteInfoBean() urmx})=  
{//nSplitter的缺省值为5 !v(j#N< m  
//default value of nSplitter is 5 C5mq@$6  
this("","","",5); SQ7Ws u>T@  
} 7i?"akr4  
ximW!y7  
b4%sOn,  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) csP 5R3  
{ ?m5@ 63 5  
sSiteURL= sURL; 2(V;OWY(@  
sFilePath = sPath; xu9K\/{7  
sFileName = sName; SYkLia(Ty  
this.nSplitter = nSpiltter; v|Y:'5`V  
`7<4]#b^o  
m'D_zb9+  
} Y?Ph%i2E  
?HT+| !4p  
';"W0  
public String getSSiteURL() %D|p7&  
{  ,r\  
return sSiteURL; O ;,BzA-n  
} :%ms6j/B&V  
* S4IMfp  
1fwjW0t  
public void setSSiteURL(String value) ]6)^+(zU  
{ "w3#2q&  
sSiteURL = value; pC<~\RR  
} 1FC'DH!  
A/eZnsk  
07pASZ;~  
public String getSFilePath() ( <~  
{ *`.h8gTD,  
return sFilePath; bHx09F]  
} r}>8FE9S'H  
1&%6sZN  
"b)Y5[nW  
public void setSFilePath(String value) vsc)EM ]  
{ .f)&;Af^  
sFilePath = value; !,8jB(  
} dq d:V$o  
z|,YO6(L  
LLp/ SWe  
public String getSFileName() /[ _aw&W}Z  
{ ^2C)Wk$  
return sFileName; -1'O  
} hKa<9>MI`  
kY d'6+m  
:iW+CD)j  
public void setSFileName(String value) ~*aPeJ  
{ F91uuSSL  
sFileName = value; f|U;4{ k  
} s|*0cK!K^  
cE (P^;7D  
9i+OYWUO  
public int getNSplitter() Wp7lDx  
{ M*XAyo4 fI  
return nSplitter; -J7BEx  
} ?#N: a  
kn2s,%\`<p  
[ 6+iR  
public void setNSplitter(int nCount) +XL^dzN[|$  
{ p5RnFe l  
nSplitter = nCount; KO*# ^+g  
} z$#q'+$  
} 5q<cZ)v#&  
NX wthc3  
Y#aL]LxZE  
/* }_,\yC9F  
**Utility.java T!-*;yu  
*/ <%d/"XNg[D  
package NetFox; |"}F cS y  
Vf28R,~m  
MR")  
public class Utility { rw:z|-r  
B49: R >  
6-"@j@l5<  
public Utility() Vr/UY79  
{ (2 nSZRB  
Q,pnh!.-c  
"==fWf  
} =rL%P~0wq  
W4MU^``   
//线程睡眠 `<Ry_}V  
public static void sleep(int nSecond) EJAk'L+nuH  
{ ANIx0*Yl(  
try{ Ax"]+pb  
Thread.sleep(nSecond); @4)NxdOE  
} >* Ag0.Az  
catch(Exception e) <Z b~tYp  
{ eyM<#3\\S  
e.printStackTrace (); /x2-$a:<  
} =&%}p[ 3g  
} Nuc;Y  
\mK;BWg)  
//日志 aMU0BS"   
public static void log(String sMsg) Gm`#0)VC  
{ zWs ("L(#s  
System.err.println(sMsg); h7 r *5E  
} }4Q~<2  
3?%?J^/a  
]1Wh3C  
public static void log(int sMsg) <8J_[ S  
{ 9w)W|9  
System.err.println(sMsg); oz.#+t%X$b  
} #uRj9|E7  
}  _'Jz+f.  
}dv$^4 *n  
6&J7=g%G  
/* t,bQ@x{zVC  
**TestMethod.java >O;V[H2[  
*/ X }V}%  
package NetFox; 9~7s*3zI  
0|i3#G_~  
)~X.x"}8k  
public class TestMethod { jw 4B^2}  
WilKC|R]P  
I$0O4  
public TestMethod() ?Yf0h_>  
{ ///xx/weblogic60b2_win.exe mJU1n  
try{ 4Tdp;n\F  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Mg"e$m  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,1K`w:uhS  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _O,k0O   
fileFetch.start(); Q[n*ce7L0  
} }Fq~!D Ee  
catch(Exception e){e.printStackTrace ();} f (Su  
e 48N[p  
>TQNrS^$J  
} s~p(59  
;_~9".'<d  
>0X_UDAWz  
public static void main(String[] args) [r#m +R"N  
{ f>CJ1 ;][{  
new TestMethod(); ;% <[*T:*'  
} K[q{)>,9  
} |tr^ `Z  
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