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http断点续传简单实现(java)

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/* Y|W#VyM-  
**SiteFileFetch.java XIl#0-E0X  
*/ PQz[IZ  
package NetFox; C]ax}P>BQ  
import java.io.*; j W[EjhsH  
import java.net.*; mJH4M9WJ]  
(/t{z =  
_p9 _Pg8  
public class SiteFileFetch extends Thread { sAZL,w  
0TiDQ4}i[  
n^l5M^.  
SiteInfoBean siteInfoBean = null; //文件信息Bean `q1-yH0~4  
long[] nStartPos; //开始位置 [d>2F  
long[] nEndPos; //结束位置 fQ_tXY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *)HVK&'  
long nFileLength; //文件长度 3jto$_3'w  
boolean bFirst = true; //是否第一次取文件 F#qc#s  
boolean bStop = false; //停止标志 aghlYcPg  
File tmpFile; //文件下载的临时信息 >gn@NJ2N  
DataOutputStream output; //输出到文件的输出流 ~uB@oKMru  
<YCR^?hJSi  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) [g+WL\1  
public SiteFileFetch(SiteInfoBean bean) throws IOException Uf?+oc'{  
{ m}6>F0Kv  
siteInfoBean = bean; I^D*) z   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Cwji,*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |47 2X&e  
if(tmpFile.exists ()) p-7?S^!l  
{ 8Kn}o@Yd  
bFirst = false; !&v"+ K3lU  
read_nPos(); yV&]i-ey  
} PX?^v8wlqL  
else ";n%^I}  
{ j1ap,<\.k  
nStartPos = new long[bean.getNSplitter()]; /u"Iq8QA  
nEndPos = new long[bean.getNSplitter()]; !Uhcjfq`e  
} x"Ij+~i{l  
s(MdjWw  
CwO$EL:[`  
\z.p [;'ir  
} S@4bpnhK  
(YYwn@NGj  
Y`xAJ#= ,i  
public void run() Xxm7s S  
{ a4q02 cV  
//获得文件长度 ]Rmu +N|  
//分割文件 Kf6D$}  
//实例FileSplitterFetch V:gXP1P  
//启动FileSplitterFetch线程 oV~S4|9:  
//等待子线程返回 8yuTT^  
try{ B{V(g"dM  
if(bFirst) pT;xoe   
{ SNHAL F  
nFileLength = getFileSize(); m x2Ov u  
if(nFileLength == -1) dmMrZ1u2  
{ MLmv+  
System.err.println("File Length is not known!"); ; y>}LGG  
} ]\3<UL  
else if(nFileLength == -2) YD5mJ[1t"2  
{ k{^iv:  
System.err.println("File is not access!"); mDA1$fj"  
} c{i\F D  
else 2y9$ k\<xV  
{ pEb/yIT"  
for(int i=0;i<nStartPos.length;i++) #5^S@}e  
{ 2j[; M-3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \Oe8h#%  
} YXGxE&!  
for(int i=0;i<nEndPos.length-1;i++) Z$K[e  
{ XBTjb  
nEndPos = nStartPos[i+1]; OX.g~M ig|  
} byIP]7Ld  
nEndPos[nEndPos.length-1] = nFileLength; biH ZyUJ  
} /J&_ZDNV~  
} ZgxpHo  
q9(hn_X@/  
NF_[q(k'  
//启动子线程 9]a!1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #23($CSE  
for(int i=0;i<nStartPos.length;i++) %D+NrL(  
{ XC,by&nY<y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %lGg}9k'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), TnPx.mwK\  
nStartPos,nEndPos,i); 4'L.I%#tZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <!~NG3KW[>  
fileSplitterFetch.start(); &3YXDNm  
} rmhL|! Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZV~9{E8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); d-#yN:}0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &t74T"(d  
nEndPos = " + nFileLength); q&: t$tSS  
// fileSplitterFetch[nPos.length-1].start(); !f# [4Xw  
b*cVC^{Dy  
*Di ;Gf@  
//等待子线程结束 B|- W  
//int count = 0; 8?t}S2n2  
//是否结束while循环 l'"Ici#7Ls  
boolean breakWhile = false; ztV%W6  
bm(.(0MI  
p+:MZP -%(  
while(!bStop) OJ)XJL  
{ Cvtz&dH  
write_nPos(); iZ2nBi Q  
Utility.sleep(500); F6 f  
breakWhile = true; 2?c%<_jPA  
;VPYWss  
ljk,R G  
for(int i=0;i<nStartPos.length;i++) B..> *Xb  
{ zR }vw{  
if(!fileSplitterFetch.bDownOver) [vcSt5R=  
{ uSNlI78D  
breakWhile = false; 8Y~\:3&1<  
break; `FIS2sl/  
} <f@ A\  
} -K iI&Q  
if(breakWhile) A55F* d  
break; F3<Ip~K  
||rZ+<  
e u?DSad  
//count++; [J43]  
//if(count>4) Zex`n:Wl?j  
// siteStop(); 4tFnZ2x  
} >W=^>8u  
0|`iop%(n  
Ly`FU)  
System.err.println("文件下载结束!"); qUG)+~g`  
} QQX7p!~E  
catch(Exception e){e.printStackTrace ();} {3\{aZ8)  
} XM?C7/^k  
3qrjb]E%}  
$WZHkV  
//获得文件长度 Z`{GjV3%wH  
public long getFileSize() Xa&0j&AH  
{ 604^~6  
int nFileLength = -1; C )+%9Edg  
try{ Cg%}=  
URL url = new URL(siteInfoBean.getSSiteURL()); w:@W/e*9N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jg=}l1M"  
httpConnection.setRequestProperty("User-Agent","NetFox"); UJrN+RtL  
LKu ,H  
#:} mi;{  
int responseCode=httpConnection.getResponseCode(); (Z at|R.F  
if(responseCode>=400) hE}y/A[  
{ 9I*`~il>{  
processErrorCode(responseCode); C: a</Sl  
return -2; //-2 represent access is error \%]!/&>{6  
} ' 8UhYwyr  
to;cF6X  
$3{I'r]  
String sHeader; ,IQ%7*f;O_  
{$)pkhJ  
%51HJB}C]  
for(int i=1;;i++) -v?)E S  
{ <~35tOpv  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n.xOu`gj  
//Utility.log(in.readLine()); t$b{zv9C  
sHeader=httpConnection.getHeaderFieldKey(i); OT}^dPQe  
if(sHeader!=null) 0`"DYJ}d  
{ RV, cQ K  
if(sHeader.equals("Content-Length")) OJPi*i5*  
{ S *K0OUq  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); qiyJ4^1  
break; \Gz 79VW  
} !9.`zW"40  
} NIxtT>[+3  
else #%SF2PB;  
break; pDG>9P#mO  
} t[b@P<F  
} {DbWk>[DkG  
catch(IOException e){e.printStackTrace ();} iGsD!2  
catch(Exception e){e.printStackTrace ();} h v/+  
|FJc'&)J"  
!jyy`q=  
Utility.log(nFileLength); YfU6 mQ  
'n!kqP  
9Gk#2  
return nFileLength; -v62 s  
} '7>Yr zq  
 OiMr,  
zr[|~-  
//保存下载信息(文件指针位置) DO9_o9'  
private void write_nPos() |bv7N@?e  
{ \-R\xL  
try{ *aS[^iX?s  
output = new DataOutputStream(new FileOutputStream(tmpFile)); EMMp4KKOx+  
output.writeInt(nStartPos.length); CGJ>j}C  
for(int i=0;i<nStartPos.length;i++) Tlz~o[`&  
{ r>x>aJ  
// output.writeLong(nPos); be:=-B7!  
output.writeLong(fileSplitterFetch.nStartPos); nSeb?|$D6  
output.writeLong(fileSplitterFetch.nEndPos); tz`T#9  
} }}w Z  
output.close(); R'x^Y"  
} -)Y[t Z^*`  
catch(IOException e){e.printStackTrace ();} Dh B*k<S  
catch(Exception e){e.printStackTrace ();} v!%VH?cA8  
} #kPsg9Y  
@w@ `-1  
@1iH4RE*  
//读取保存的下载信息(文件指针位置) \6K1Z!*;  
private void read_nPos() L|K^w *\C  
{ 5r(Y,m"?  
try{ &L4>w.b"N  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H4JwgQ  
int nCount = input.readInt(); yDXW#q  
nStartPos = new long[nCount]; IltU6=]"l  
nEndPos = new long[nCount]; 53)*i\9&  
for(int i=0;i<nStartPos.length;i++) Lo^gg#o  
{ K8g9IZ*lT  
nStartPos = input.readLong(); ]:F?k#c  
nEndPos = input.readLong(); K{[N.dX(  
} Q804_F F#  
input.close(); pQ9~^  
} ^fxS=Qs+  
catch(IOException e){e.printStackTrace ();} TrmrA$5f  
catch(Exception e){e.printStackTrace ();} 0%>_fMaA  
} <<[\ Rv  
-JfO} DRI  
[eO6 H2@=z  
private void processErrorCode(int nErrorCode) XZ[3v9?&n  
{ [Cf{2WB:7  
System.err.println("Error Code : " + nErrorCode); >19j_[n@VC  
} XCQPVSh  
l6k.`1.In  
} {<L<  
//停止文件下载 `*HM5 1U  
public void siteStop() "|W``&pM  
{ i4r8146D[  
bStop = true; =E4~/F}9/T  
for(int i=0;i<nStartPos.length;i++) $SPA'63AC  
fileSplitterFetch.splitterStop(); i@hW" [A  
C{P:1ELYXH  
>q)VHV9P  
} p 28=l5y+  
} bx=9XZ9g  
//负责部分文件的抓取 zvHeoM ,  
**FileSplitterFetch.java s.9_/cFWB  
*/ rWD*DmY@"  
package NetFox; f,QBj{M,  
+a!uS0fIJi  
]O.Z4+6w  
import java.io.*; kCZxv"Ts  
import java.net.*; 5Int,SX  
t6a$ZN;  
7/GL@H  
public class FileSplitterFetch extends Thread { g RBbL1  
F=r`'\JV[  
f4r)g2Zb[  
String sURL; //File URL h^ =9R6im  
long nStartPos; //File Snippet Start Position RqRyZ*n  
long nEndPos; //File Snippet End Position +DA ,|~k_  
int nThreadID; //Thread's ID sRDxa5<MD  
boolean bDownOver = false; //Downing is over T@\%h8@~]  
boolean bStop = false; //Stop identical I18<brZJ  
FileAccessI fileAccessI = null; //File Access interface tA]Y=U+Q  
Q2nqA1sRk  
1]]#HTwX  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException i :Sih"=  
{ Nvj0MD{ X  
this.sURL = sURL; BhC>G2 ^7  
this.nStartPos = nStart; P1A5Qq  
this.nEndPos = nEnd; e]@R'oM?#`  
nThreadID = id; w^wh|'u^_@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 J^)=8cy  
} Y!w {,\3  
^.~m4t`U  
Tg\wBhJr|  
public void run() %:/?eZ  
{ `sPH7^R  
while(nStartPos < nEndPos && !bStop) ewORb  
{ _1kcz]]F  
jRYW3a_7  
Lm"zW>v  
try{ (YKkJ  
URL url = new URL(sURL); Xgyi}~AoaU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Gf y9?sa  
httpConnection.setRequestProperty("User-Agent","NetFox"); c},wW@SF2W  
String sProperty = "bytes="+nStartPos+"-"; 6 P U]I+  
httpConnection.setRequestProperty("RANGE",sProperty); m.2=,,r<Fq  
Utility.log(sProperty); %Tm8sQ)1  
B7ty*)i?  
1_0\_|  
InputStream input = httpConnection.getInputStream(); kH}HFl  
//logResponseHead(httpConnection); pIP ^/H  
N@G~+GCxL  
(7J (.EG2e  
byte[] b = new byte[1024]; G*\U'w4w|*  
int nRead; /j:fc?yv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) wC~LZSTt  
{ $KMxq=  
nStartPos += fileAccessI.write(b,0,nRead); 6h3TU,$r  
//if(nThreadID == 1) fs;pX/:FR  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4NxI:d$&*  
} %% A==_b  
*e}1KcJ  
-G@:uxB  
Utility.log("Thread " + nThreadID + " is over!"); jpRC6b?  
bDownOver = true; 6qH^&O][  
//nPos = fileAccessI.write (b,0,nRead); d gRTV<vM  
} o=ULo &9  
catch(Exception e){e.printStackTrace ();} I!;vy/r  
} &&K"3"um  
} SvN2}]Kh  
gq[`g=x  
_yP02a^2  
//打印回应的头信息 sTChbks  
public void logResponseHead(HttpURLConnection con) +#MQ8d  
{ 1J @43>u{  
for(int i=1;;i++) :elTqw>pn  
{ kQQhZ8Ch  
String header=con.getHeaderFieldKey(i); /Vy,6:$H3  
if(header!=null) &L`yX/N2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); h(MS>=  
Utility.log(header+" : "+con.getHeaderField(header)); MR-cOPn  
else =VOl  *  
break; E!zAUEVQm[  
} T,SCK^  
} PuoN<9 #  
ZKco  
_ pKWDMB$z  
public void splitterStop() $3D#U^7i  
{ cu#s}* Ip  
bStop = true; [>wvVv  
} :Yy8Ie#  
(043G[H'.  
F,>-+~L=  
} tDwj~{a~  
A.@Af+  
rJqRzF{|P6  
/* 8jz[;.jP",  
**FileAccess.java F}dq~QCzw  
*//文件访问(定位,写) $mZpX:7/u8  
package NetFox; CY i{WV(:  
import java.io.*; bf&k:.v'8  
c`x[C  
tF=Y3W+L  
public class FileAccessI implements Serializable{ nH -1,#`g  
F\( 7B#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 RRBBz7:~  
RandomAccessFile oSavedFile; PML +$  
long nPos; j+7ok 5J#  
?)V}_%fVv  
yNk E>  
public FileAccessI() throws IOException kFsq23Ne  
{ U**v'%{s  
this("",0); 4C[n@ p2  
} hDc)\vzr  
[tY+P7j9)  
GYM6 `  
public FileAccessI(String sName,long nPos) throws IOException 6A \Z221E  
{ 5|Or,8r(C  
oSavedFile = new RandomAccessFile(sName,"rw"); g7),si*  
this.nPos = nPos; 6K 6uB ~  
oSavedFile.seek(nPos); kx_PMpc  
} i1JWdHt  
Qpaan  
E+|r h-M7  
public synchronized int write(byte[] b,int nStart,int nLen) vspub^;5\  
{ 8 y+Nl&"V  
int n = -1;  }j /r  
try{ Q($aN-   
oSavedFile.write(b,nStart,nLen); 2lm{:tS  
n = nLen; *N|s+  
} y/}ENUGR  
catch(IOException e) "=r"c$xou  
{ - yn;Jo2-  
e.printStackTrace (); Up|>)WFw"  
} | *J-9  
#v QyECf  
?g~g GQV  
return n; Z6XP..  
} ^&-H"jF  
ZFsJeF'"  
q|fZdTw  
} |L"!^Y#=D  
byUz  
qn4jy6  
/* 5{uK;Vxse  
**SiteInfoBean.java ' y9yx[P  
*/ Md4JaFA(  
package NetFox; '5n67Hl 1  
(xhwl=MX)  
:5M7*s)e16  
public class SiteInfoBean { xHMbtY  
K@PQLL#yJp  
:x<'>)6  
private String sSiteURL; //Site's URL kW=GFj)L  
private String sFilePath; //Saved File's Path r+WY7'c  
private String sFileName; //Saved File's Name fsDwfwil*  
private int nSplitter; //Count of Splited Downloading File >IzUn: 0F  
td6$w:SN,l  
@xI:ZtM  
public SiteInfoBean()  4[] /  
{//nSplitter的缺省值为5 "x)xjL  
//default value of nSplitter is 5 F]SA1ry  
this("","","",5); $SmmrM  
} =1}Umn|ZLS  
C'c9AoE5>  
p#V h[UTl^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mtON dI  
{ )KLsa`RV:  
sSiteURL= sURL; %4Thb\T  
sFilePath = sPath; bqt*d)$  
sFileName = sName; W l+[{#  
this.nSplitter = nSpiltter; uKcwVEu  
uM^eoh_  
m% {4  
} =tv,B3Mo  
1E*No1  
iJrF$Xw  
public String getSSiteURL() {G D<s))  
{ 2AAZZx +$  
return sSiteURL; De(\ <H#  
} Hi 1@  
E\(dyq/  
_IOt(Zb(  
public void setSSiteURL(String value) lc71Pp>  
{ v3i]z9`  
sSiteURL = value; U Ux]  
} c_fx,; ;  
v{}i`|~J  
'$3]U5KOwK  
public String getSFilePath() exqFwmhh  
{ %Hk9.1hn5  
return sFilePath; x}W,B,q  
} %\ i 7  
ZgcJxWC<  
hZ0CnY8 '  
public void setSFilePath(String value) .#,!&Lt  
{ G' ~Z'  
sFilePath = value; AAr[xo iYp  
} 3YG[~o|4  
Dg$Z5`%k8  
^qaS  
public String getSFileName() `!.)"BI/s  
{ )@xHL]!5m  
return sFileName; GIt~"X  
} v: Av 2y  
X4:\Shb97  
1jJ>(S  
public void setSFileName(String value) nl)!)t=n  
{ XA~Cc<v  
sFileName = value; .X;zEyd  
} 8X@p?43  
S0\;FmLIc  
>[=fbL@N<@  
public int getNSplitter() ^ 2"r't  
{ nVF?.c  
return nSplitter; Dk!;s8}*c  
} +mQMzZZTZ  
9y(75Bn9  
R&cOhUj22J  
public void setNSplitter(int nCount) 37hs/=x  
{ R#ABda9  
nSplitter = nCount; GHaOFLY  
} .a%D:4GYR  
} ,Jy@n]x  
4LRrrW  
vps</f!  
/* v2e*mNK5  
**Utility.java =l_B58wrx  
*/ )uvs%hK  
package NetFox; [*<F   
_;G. QwHr  
,9I %t%sb  
public class Utility { uXX3IE[  
o5 UM)g  
+>#SB"'  
public Utility() v=A ]#O%  
{ ^tS{a*Yn  
y9cDPwi:b  
}fps~R  
} CbmT aEaP  
/DG+8u  
//线程睡眠 ?v4-<ewD  
public static void sleep(int nSecond) ~s@PP'!  
{  -a``  
try{ eSNwAExm  
Thread.sleep(nSecond); }Ut*Y*  
} Lo^0VD!O  
catch(Exception e) |H`}w2U[j  
{ "|?zQ?E  
e.printStackTrace (); @6eM{3E.  
} nRYHp7`  
} v71j1Q}6  
"P) f,n  
//日志 f}JiYZ  
public static void log(String sMsg) {9kH<,PJ;!  
{ F)ak5  
System.err.println(sMsg); {:U zW\5l)  
} O)y|G%O  
J<g$hk  
!^{0vFWE  
public static void log(int sMsg) D00I!D16  
{ B?BB  
System.err.println(sMsg); m0}Pq{ g  
} B$R"Ntp  
} {E6M_qZ  
xbbQ)sH&m  
y0!-].5UH  
/* d5zv8?|X+  
**TestMethod.java snPM&  
*/ xq`mo  
package NetFox; OF[y$<jM  
MKqMH,O  
T5* t~`bfU  
public class TestMethod { !S0$W?*  
K4 \{G  
,$"*X-1  
public TestMethod() bXVH7Fy  
{ ///xx/weblogic60b2_win.exe /.54r/FN')  
try{ ZY_aE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {+`'ZU6C  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c1!0Z28  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }I3 ZNd   
fileFetch.start(); 0 rM'VgB  
} ;WydXQ}Q^  
catch(Exception e){e.printStackTrace ();} eIZ7uSl  
yQAW\0`  
Y nD_:ZK  
} :c4iXK0_^?  
W6~aL\[  
'o D31\@I  
public static void main(String[] args) )uj:k*`)  
{ C[E[|s*l  
new TestMethod(); 6j*L]S c  
} v[k;R  
} /INjP~C  
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