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http断点续传简单实现(java)

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/* ?3"D| cS1  
**SiteFileFetch.java R{OE{8;  
*/ :hhE=A>X  
package NetFox; jcv1z v.  
import java.io.*; BtNW5'^  
import java.net.*; v<J;S9u=  
 1u S>{M  
sG1]A:_<C  
public class SiteFileFetch extends Thread { ap$ tu3j  
(HrkUkw  
N5rG.6K  
SiteInfoBean siteInfoBean = null; //文件信息Bean i\Q"a B"r  
long[] nStartPos; //开始位置 c] >&6-;rf  
long[] nEndPos; //结束位置 &6^W% r  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :2UC{_  
long nFileLength; //文件长度 b-(UsY:  
boolean bFirst = true; //是否第一次取文件 :kiO  
boolean bStop = false; //停止标志 64 \5v?C  
File tmpFile; //文件下载的临时信息 >eG&gc@$1$  
DataOutputStream output; //输出到文件的输出流 QY\wQjwuW  
D>7_P7]y  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) l;Wy,?p  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,<P[CUD&&  
{ *A1TDc$  
siteInfoBean = bean; }jY[| >z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); cVHE}0Xd(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %}ApO{  
if(tmpFile.exists ()) EAd:`X,Y  
{ 9X {nJ"  
bFirst = false; UK <DcM~n  
read_nPos(); L5k>;|SA  
} (8-lDoW  
else 0-~6} r$  
{ o? O,nD 6  
nStartPos = new long[bean.getNSplitter()]; r?yJ  
nEndPos = new long[bean.getNSplitter()]; ;Y|~!%2~  
} 5fx,rtY2sQ  
> v!c\  
BQ}.+T\  
7" STS7_  
} FvNSu"O~K1  
v.LUK  
wAOVH].  
public void run() nM.?Q}yO~  
{ Nj-rZ%&  
//获得文件长度 c.{&~  
//分割文件 Nb!6YY=Ez-  
//实例FileSplitterFetch ;7n*PBUJJ  
//启动FileSplitterFetch线程 $t H.np  
//等待子线程返回 B?ob{K@  
try{ >'TD?@sr  
if(bFirst) F%+rOT<5  
{ 6u, 0y$3  
nFileLength = getFileSize(); "QFADk1  
if(nFileLength == -1) AB &wn>q  
{ ;{q) |GRF  
System.err.println("File Length is not known!"); q>:&xR"ra  
} rD U6 5j  
else if(nFileLength == -2) 5<?c_l9X^  
{ rWfurB5f  
System.err.println("File is not access!"); T!xy^n]}  
} Q%VR@[`\  
else P"_}F  
{ L%O8vn^3  
for(int i=0;i<nStartPos.length;i++) Fx99"3`3  
{ ^\kHEM|5v  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); O-lh\9{'R  
} ^21f^>k(  
for(int i=0;i<nEndPos.length-1;i++) yqb <<4I  
{ 2d;xAX]  
nEndPos = nStartPos[i+1]; "X(=  
} !@Vp Bl  
nEndPos[nEndPos.length-1] = nFileLength; -zLI!F 0  
} ZFuJ2 :  
} @$yYljP  
cTa D{!zm5  
?| LB:8  
//启动子线程 hGo|2@sc  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f uN XY-;  
for(int i=0;i<nStartPos.length;i++) EbYH?hPo  
{ O#5( U. E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /N{@g.edL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  <IDzv'  
nStartPos,nEndPos,i); 0:+uw` %  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kBT}Siw  
fileSplitterFetch.start(); ,Y8X"~{A  
} k\<Ln w  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N b[o6AX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~rX6owBq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %e<dV\x?T  
nEndPos = " + nFileLength); jL%}y1m?  
// fileSplitterFetch[nPos.length-1].start(); ~d `4W<1a  
N&h!14]{ Z  
6Oba}`)q9  
//等待子线程结束 8 (h  
//int count = 0; ^QQ NJ  
//是否结束while循环 sK/"  
boolean breakWhile = false; i6:yNb ='  
DF|lUO]:  
"EhO )lR  
while(!bStop) }~'Wz*Gm  
{ "}+/ 0$F  
write_nPos(); y/6LMAI  
Utility.sleep(500); |B$\3,  
breakWhile = true; 4^ 6L])y  
KmOa^vY1.T  
xLK0~|_#!  
for(int i=0;i<nStartPos.length;i++) P2JRsZ.  
{ j4r,_lH^r  
if(!fileSplitterFetch.bDownOver) B]F7t4Y!  
{ "I FGW4FnL  
breakWhile = false; P}QbxkS 8  
break; 9ufs6 z  
} AHD%6 \$  
} hBE>ea  
if(breakWhile) pDq_nx9  
break; TPFmSDq  
"$pg mf2  
U?j>28  
//count++; K.1yncS^  
//if(count>4) slfVQ809  
// siteStop(); *Y0,d`  
} nnl9I4-O  
NB +O;  
2vQ^519  
System.err.println("文件下载结束!"); k K|+W,  
} !*UdY(  
catch(Exception e){e.printStackTrace ();} )_K@?rWS  
} !QS<;)N@  
'\\Cpc_g  
J}\]<aC  
//获得文件长度 4F6o  
public long getFileSize() _N';`wjDY  
{ xG/qDc  
int nFileLength = -1; t3g! 5  
try{ i4rF~'h@  
URL url = new URL(siteInfoBean.getSSiteURL()); lB~'7r`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $i>VI  
httpConnection.setRequestProperty("User-Agent","NetFox"); oa !P]r  
{=7i}xY]T  
1^^D :tt  
int responseCode=httpConnection.getResponseCode(); S Tk#hhx  
if(responseCode>=400) >D62l*VC)  
{ 1tz .e\  
processErrorCode(responseCode); f.^w/ GJO/  
return -2; //-2 represent access is error ScoHtX3  
} tgA |Vwwk  
Pp hQa!F$  
S9oGf  
String sHeader; ]X|G+[Ujv  
S`w)b'B!M  
!PIdw~YC  
for(int i=1;;i++) S]/ +n>  
{ D07u?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *S_Iza #&x  
//Utility.log(in.readLine()); Pv.@Y 30  
sHeader=httpConnection.getHeaderFieldKey(i); 5K~6`  
if(sHeader!=null) <t37DnCgI  
{ AB\4+ CLV  
if(sHeader.equals("Content-Length")) n5>N9lc  
{ TJ:Lz]l >  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {hR2NUm  
break; |h/2'zd^-  
} ,0~TvJS  
} $7d"9s\$"  
else $u"$mg7x  
break; ??V["o T  
} R,1,4XT  
} ^0-=(JrC  
catch(IOException e){e.printStackTrace ();} b.;}Hq>  
catch(Exception e){e.printStackTrace ();} Tj9q(Vq  
rtE,SN  
h cXqg  
Utility.log(nFileLength); IyP].g1"U  
X&Lt?e,&  
=T$- #bA)  
return nFileLength; ]#n4A|&H  
} 1_lL?S3,a@  
w,9F riW  
u`|fmVI  
//保存下载信息(文件指针位置) \]%U?`A  
private void write_nPos() Y&:i^k  
{ 3: Uik  
try{ o w[qpP[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); p]4 sN  
output.writeInt(nStartPos.length); 3IFU{0a`  
for(int i=0;i<nStartPos.length;i++) #mYxO  
{ =YIQ _,{u  
// output.writeLong(nPos); HXI}f\6x  
output.writeLong(fileSplitterFetch.nStartPos); E:k?*l  
output.writeLong(fileSplitterFetch.nEndPos); 6~>k]G  
} (Lnh> '2  
output.close(); cC.DBYV+-  
} R 0}%   
catch(IOException e){e.printStackTrace ();} 1[^d8!U  
catch(Exception e){e.printStackTrace ();} dZmq  
} y>8?RX8  
sN2l[Ous  
*cIXae^Y7  
//读取保存的下载信息(文件指针位置) +)S X  
private void read_nPos() ? Q}{&J  
{ VIzZmd  
try{ EA.U>5Fq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &=bI3-  
int nCount = input.readInt(); to7)gOX(  
nStartPos = new long[nCount]; |=s3a5sl  
nEndPos = new long[nCount]; 4>*`26  
for(int i=0;i<nStartPos.length;i++) Vk-_H)*r  
{ W:\VFP f2  
nStartPos = input.readLong(); gzF&7trN  
nEndPos = input.readLong(); +E4 _^  
} YSyW '~!b  
input.close(); fZ$2bI=  
} LKcrr;  
catch(IOException e){e.printStackTrace ();} UhK,H   
catch(Exception e){e.printStackTrace ();} GWKefH  
} 3yN1cd"#?  
r$5!KO  
51x,[y+Xe  
private void processErrorCode(int nErrorCode) x{$NstGB  
{ c&&UT-Z  
System.err.println("Error Code : " + nErrorCode); E<dN=#f6  
} &&O=v]6,V  
*Y Ox`z!R  
WM26-nR  
//停止文件下载 1~ Nz6  
public void siteStop() ~\P.gSiz  
{ ^iNR(cwgX  
bStop = true; Yo:&\a K[  
for(int i=0;i<nStartPos.length;i++) l<0V0R(  
fileSplitterFetch.splitterStop(); > R=YF*t  
zdCt#=QV?R  
-eTGRr  
} d yd_dK/  
} 7(H/|2;-d8  
//负责部分文件的抓取 D$HxPfDZ  
**FileSplitterFetch.java srL,9)O C  
*/ xh0!H| R  
package NetFox; uypD`%pC  
AI2CfH#:C  
V 6F,X`7  
import java.io.*; }qTvUs  
import java.net.*; $`%.Y&A  
/l L*U  
s/V[tEC*z  
public class FileSplitterFetch extends Thread { 6F2}|c  
rQJoaP+\q  
N5^:2ag  
String sURL; //File URL R)/w   
long nStartPos; //File Snippet Start Position +dfSCs  
long nEndPos; //File Snippet End Position I$$!YMm.N  
int nThreadID; //Thread's ID i+}M#Y-O  
boolean bDownOver = false; //Downing is over V6Y!0,w!a  
boolean bStop = false; //Stop identical bGZy0.  
FileAccessI fileAccessI = null; //File Access interface h(BN6ZrzKd  
aC*J=_9o #  
n" sGI  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `|R{^Sk1o  
{ K\G|q}E/1  
this.sURL = sURL; TUG3#PSnm*  
this.nStartPos = nStart; =B 9U  
this.nEndPos = nEnd; xQQ6D  
nThreadID = id; o&=m]hKpQl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6o!"$IH4  
} 8MIHp[vm%  
Ne%X:h  
T~la,>p|}  
public void run() c}A^0,"z>  
{ TO<g@u]*  
while(nStartPos < nEndPos && !bStop) #ed]zI9O  
{ Uu ,Re  
j2+&B9 (  
)jg3`I@  
try{ 3jeR;N]x  
URL url = new URL(sURL); 5@Sb[za  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b~r ?#2K  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~jgd92`{z  
String sProperty = "bytes="+nStartPos+"-"; V;$lgTs|'  
httpConnection.setRequestProperty("RANGE",sProperty); IcB>Hg5  
Utility.log(sProperty); \a<E3 <  
AK[c!mzx  
q_!3<.sf  
InputStream input = httpConnection.getInputStream(); >a,w8^7  
//logResponseHead(httpConnection);  u!(|y9p  
|$Td-M^)  
QeGU]WU{  
byte[] b = new byte[1024]; 1z)+P1nH]  
int nRead; {z w#My   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) gCmGFQE-f  
{ V5=Injs *  
nStartPos += fileAccessI.write(b,0,nRead); bbz86]AhY  
//if(nThreadID == 1) OnG?@sW+4!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p?Y1^/   
} 3'8~H]<W  
7\.5G4dr%  
|nD`0Rbw  
Utility.log("Thread " + nThreadID + " is over!"); IySlu^a  
bDownOver = true; =uHTpHR  
//nPos = fileAccessI.write (b,0,nRead); Xr@0RFdr[  
} x[]n\\a?  
catch(Exception e){e.printStackTrace ();} M:ttzsd  
} sviGS&J9h  
} 9rhz#w  
bp }~{]:b  
(q)W<GYP  
//打印回应的头信息 @ ~PL|Pp_  
public void logResponseHead(HttpURLConnection con) xMe[/7)4  
{ &4DWLI  
for(int i=1;;i++) ~U`aH~R  
{ 1_A< nt?'R  
String header=con.getHeaderFieldKey(i); y<)x`&pcD  
if(header!=null) f+rBIE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); wEdXaOEB5  
Utility.log(header+" : "+con.getHeaderField(header)); |KuH2, n0  
else Zvc{o8^z  
break; \hg12],#:@  
} x k#/J]j  
} kc}e},k  
VP[ J#TPU  
4]Krx m`8  
public void splitterStop() C@xh$(y  
{ 86[T BX5'  
bStop = true; TtHqdKL  
} o_?YYw-:  
-q[?,h  
7uYJ _R  
} 3iDRt&y=.  
h 9No'!'!  
O`*}N1No[  
/* *edB3!!  
**FileAccess.java ondF  
*//文件访问(定位,写) m/<7FU8  
package NetFox; Uc.K6%iI  
import java.io.*; \ZXH(N*>2t  
Q~nc:eWD  
}=NjFK_6  
public class FileAccessI implements Serializable{ 1%H]2@  
8!1vsEqv  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 G"wy?  
RandomAccessFile oSavedFile; 0Y{A  
long nPos; [^#6.xH  
 IS!sJc  
moh7:g  
public FileAccessI() throws IOException k<m{Wp;-  
{ ~h -0rE  
this("",0); gE|_hfm(  
} "Q ^Ck7  
'(;`t1V8k  
rlgp1>89  
public FileAccessI(String sName,long nPos) throws IOException -Zkl\A$>  
{ G >bQlZG  
oSavedFile = new RandomAccessFile(sName,"rw"); c{z QX0  
this.nPos = nPos; >a[)F  
oSavedFile.seek(nPos); +Ibcc8Qud  
} L9"V$MO  
5Osx__6$t  
-|T.APxB  
public synchronized int write(byte[] b,int nStart,int nLen) SO9j/  
{ 2ACN5lyUS  
int n = -1; L'.7V ~b{  
try{ 525W; mu{  
oSavedFile.write(b,nStart,nLen); Jc/*w  
n = nLen; J&wrBVv1uk  
} 0KE+RzrB  
catch(IOException e) {U>B\D  
{ Y$shn]~  
e.printStackTrace (); V|)3l7IC<  
} (i1 ]+.  
,F]Y,"x:  
jUYb8:B  
return n; # 2s$dI  
} K08xiMjl  
5$/ED3mcK  
ng"R[/)In  
} xM'bb5  
b 'jZ4{+W  
/{6PwlP5  
/* |#>\GU=!  
**SiteInfoBean.java u?i_N0H  
*/ 8i;EpAwB  
package NetFox; j@ lHgis  
!K'j[cA^  
h,"K+$  
public class SiteInfoBean { zuwlVn  
F|Pf-.r`t  
akoK4!z  
private String sSiteURL; //Site's URL [LbUlNq^B@  
private String sFilePath; //Saved File's Path |wZcVct~  
private String sFileName; //Saved File's Name Kf/1;:^  
private int nSplitter; //Count of Splited Downloading File fYBmW')  
KEEHb2q  
>+ul LQqe  
public SiteInfoBean() f%<kcM2  
{//nSplitter的缺省值为5 Cz` !j  
//default value of nSplitter is 5 p3`ND;KQ  
this("","","",5); n=qN@u;Fi#  
} h\k@7wgu  
c 2t<WRG  
@9Rg g9r  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) R7pdwKD  
{ `fYICp  
sSiteURL= sURL; WBvh<wTw;  
sFilePath = sPath; yPs4S?<s  
sFileName = sName; z|E/pm$^  
this.nSplitter = nSpiltter; (e.?). e  
&@NTedg!  
d e)7_pCF|  
} K Rs e  
4>x]v!d  
hH_&42E6  
public String getSSiteURL() >$Sc}a3  
{ |*W_  
return sSiteURL; 2:3-mWE  
} TrD2:N}dI  
Er509zZ,[  
1j"_@?H[  
public void setSSiteURL(String value) &3~lZa;D  
{ B)>r~v]  
sSiteURL = value; cAnL,?_v  
} Q$u&/g3NvL  
mCah{~  
n@>h"(@i  
public String getSFilePath() WZ,}]D  
{ .LMOmc=(  
return sFilePath; B /q/6Pp  
} IdTa tE|^  
{S[+hUl  
-hL0}Wy$N  
public void setSFilePath(String value) OI/m_xx@j  
{ ~0/tU#&  
sFilePath = value; =)QtE|p,77  
} xgeDfpF'  
%8C,9q  
d^b(Uo=$  
public String getSFileName() z 3((L  
{ TNun)0p  
return sFileName; +pMa-{  
} Zfwhg4G~  
vfBIQfH  
v_=xN^R  
public void setSFileName(String value) k_ d)  
{ f 0"N  
sFileName = value; LelCjC{`1  
} b~$B 0o)  
$r>$ u  
Qg9*mlm`  
public int getNSplitter() 3%HF"$Gg  
{ ,zXP,(x  
return nSplitter; q-? k=RX`  
} PH!^ww6  
(S<Z@y+d  
j<,Ho4v}_  
public void setNSplitter(int nCount) ly_@dsU'  
{ i*ibx;s-  
nSplitter = nCount; Z:_ wE62'  
} !W\Zq+^^J3  
} dOG]Yjc  
pX 4:WV  
,EsPm'`?A/  
/* 7 k:w3M  
**Utility.java U -h'a: K  
*/ |aWeo.;c  
package NetFox; *aem5 E`c  
^lw0} i  
3jeB\  
public class Utility { Gz09#nFZk  
KH=4A-e,0  
hKx*V"7/#\  
public Utility() _.}1 Y,Q  
{ %5[,U)X"  
*;N6S~_'Y  
'>"riEk  
} 'J[ n}r  
;7/ ;4Z  
//线程睡眠 J~jxmh  
public static void sleep(int nSecond) S2APqRg*  
{ c>~q2_} W(  
try{ C4,;l^?=%  
Thread.sleep(nSecond); !\'NBq,  
} KCDbE6  
catch(Exception e) LA +BH_t&  
{ 7A,QA5G ]C  
e.printStackTrace (); n8K FP  
} S`w_q=-^8  
} h=a-~= 8  
9>QGsf.3  
//日志 mQ$a^28=qR  
public static void log(String sMsg) l^~E+F~  
{ \jR('5DcB  
System.err.println(sMsg); }Cs. Hm0P  
} r}>q*yx:  
Tr\6 AN?o  
3AQu\4+A  
public static void log(int sMsg) a ](Jc)  
{ 2bnF#-(  
System.err.println(sMsg); .,vF% pQ  
} M94zlW<  
} 3QZ~t#,7ij  
O>vbAIu  
B8G9V6KS-  
/* e6 &-f  
**TestMethod.java  sJ3O ]  
*/ xPcH]Gs^b  
package NetFox; J$+K't5BZ  
U??T>  
=!R+0  
public class TestMethod { arQEi  
!dcG Bj  
|0wHNRN_  
public TestMethod() !kpnBgmU  
{ ///xx/weblogic60b2_win.exe C@P4}X0,=  
try{ H?H(=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); bP+b~!3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); L_~vPp  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ' K\ $B_  
fileFetch.start(); d*cAm$  
} .[Hv/?L  
catch(Exception e){e.printStackTrace ();} H)@f_pfj(  
qX_( M2oLU  
<H]1 6  
} ,suC`)R  
#P,C9OQD  
+`(,1L1  
public static void main(String[] args) $qp,7RW  
{ _v\L'`bif  
new TestMethod(); (\qO~)[0  
} HLruZyN4  
} 9)~Ha iVB  
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