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http断点续传简单实现(java)

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/* PKT/U^2X]  
**SiteFileFetch.java OZ*V7o  
*/ PQmgv&!DP  
package NetFox; ; 7`y##  
import java.io.*; m)A~1+M$)L  
import java.net.*; "Q:m0P xb  
lbw*T  
n]/7UH}(<&  
public class SiteFileFetch extends Thread { B rGaCja  
DQ{Yr>J  
?lh `>v  
SiteInfoBean siteInfoBean = null; //文件信息Bean 6#/Riu%  
long[] nStartPos; //开始位置 L}bS"=B[&W  
long[] nEndPos; //结束位置 , qj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !+?,y/*5(  
long nFileLength; //文件长度 9Bl c  
boolean bFirst = true; //是否第一次取文件 IH;+pN  
boolean bStop = false; //停止标志 D Hkmn  
File tmpFile; //文件下载的临时信息 -Mb`I >=  
DataOutputStream output; //输出到文件的输出流 z@lUaMm:F  
R "S,&  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ~aK@M4  
public SiteFileFetch(SiteInfoBean bean) throws IOException A9_)}  
{ 3Z *'  
siteInfoBean = bean; ;:JTb2xbb  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v2>.+Eh#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pPUv8, %  
if(tmpFile.exists ()) SBBDlr^P  
{ 87P.K Yy  
bFirst = false; e}u# :ysj  
read_nPos(); OPp>z0p%6X  
} zV(F9}^  
else /dU-$}>ZI  
{ aZ%  
nStartPos = new long[bean.getNSplitter()]; &;~x{q]3  
nEndPos = new long[bean.getNSplitter()]; o}XbFL n  
} b(lC7Xm  
|OXufV?I  
#>m#i1Nu  
w<?v78sT  
} Hq.ys>_  
mK3U*)A   
rBv  
public void run() S!0ocS!t  
{ >&K1+FSmyJ  
//获得文件长度 x)M=_u2 _  
//分割文件 2k,!P6fgl  
//实例FileSplitterFetch Mf0XQ3n`H  
//启动FileSplitterFetch线程 )q?z "F|  
//等待子线程返回 c;w%R8z  
try{ ~ {sRK  
if(bFirst) %m:T?![XO  
{ \de82 4  
nFileLength = getFileSize(); JzA`*X[  
if(nFileLength == -1) IfHB+H   
{ /n= %#{  
System.err.println("File Length is not known!"); ,LjB%f[  
} xP<cF  
else if(nFileLength == -2) {/]Ks8`Dm  
{ w$~|/UrLf  
System.err.println("File is not access!"); $`:/O A<.  
} gf `uC0  
else p&w XRI  
{ S0V%JY;Gv  
for(int i=0;i<nStartPos.length;i++) H\tz"<*``  
{ B_w;2ZuA  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); m^dKww  
} -ec ~~95  
for(int i=0;i<nEndPos.length-1;i++) bP%0T++vo  
{ B;A^5~b  
nEndPos = nStartPos[i+1]; ][8ZeM9&p  
} =;.#Bds  
nEndPos[nEndPos.length-1] = nFileLength; eW$G1h:  
} 9QaEUy*,  
} ,Mf@I5?  
{K-]nh/  
9Ny{2m=Ye  
//启动子线程 [4:_6vd7X  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; V#;6 <H"  
for(int i=0;i<nStartPos.length;i++) \S(:O8_"68  
{ HFD5* Z~M  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cyq]-B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $ig%YB  
nStartPos,nEndPos,i); Fx']kn9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )--v> *,V  
fileSplitterFetch.start(); 8fzmCRFH  
} >Z k$q~'+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Km2ppGLNn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pEIc ?i*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", rf"%D<bb  
nEndPos = " + nFileLength); unqX<6hu  
// fileSplitterFetch[nPos.length-1].start(); f $MVgX  
%\?2W8Qv_J  
eiB5 8b3  
//等待子线程结束 ,?;q$Xoi  
//int count = 0; riqvv1Nce  
//是否结束while循环 7_ g}t!b`  
boolean breakWhile = false; 8=x{>&Jr&#  
hv 18V>8  
yyJ4r}TE  
while(!bStop) _K{hq<g  
{ ^g`1SU`  
write_nPos(); SGn:f>N  
Utility.sleep(500); #z{9:o7[-  
breakWhile = true; {.tUn`j6V  
1_ uq46  
hPt(7E2ke~  
for(int i=0;i<nStartPos.length;i++)  ]qCAog  
{ +D|y))fE  
if(!fileSplitterFetch.bDownOver) y?W8FL  
{ d_BO&k<+I  
breakWhile = false; rt] @Z`w  
break; cF_hU"  
} mT\!LpX  
} V2kNJwwk  
if(breakWhile) E<;C@B  
break; ~JY<DW7  
zm rQ7(y  
IH?.s k  
//count++; F,^Q'$ !  
//if(count>4) \k;)m-0bj{  
// siteStop(); ou6|;*>d  
} l+S08IZ  
^+cf  
)`]w\s #  
System.err.println("文件下载结束!"); 6R% I)  
} X_XeI!,b  
catch(Exception e){e.printStackTrace ();} 'M2Jw8i  
} UX=JWb_uGm  
RWf4Wh?d  
('!90  
//获得文件长度 #LEK?]y  
public long getFileSize() +hg|!SS@5  
{ c,;-[sn  
int nFileLength = -1; z-nhL=  
try{ HErTFY+vC  
URL url = new URL(siteInfoBean.getSSiteURL()); 2bU 3*m^M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); weC$\st:D  
httpConnection.setRequestProperty("User-Agent","NetFox"); SLRQ3<0W_  
{zhN>n_  
i[)H!%RV*  
int responseCode=httpConnection.getResponseCode(); Dt\F]\6sd  
if(responseCode>=400) }ex2tkz  
{ Jla ;^X  
processErrorCode(responseCode); |) QE+|?P  
return -2; //-2 represent access is error Kr`Cr5v  
} RP&H9>  
p%5RE%u  
3B95t-  
String sHeader; *b9=&:pU(  
!u)ve h3x  
XPE{]4 g  
for(int i=1;;i++) zZDa7 1>  
{ <T JUKznO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \M1-  
//Utility.log(in.readLine()); 0}jB/Z_T  
sHeader=httpConnection.getHeaderFieldKey(i); DWZ!B7Ts  
if(sHeader!=null) 1QXv}36#3n  
{ <e|I?zI9-  
if(sHeader.equals("Content-Length")) hb7H- Z2  
{ 4)ez0[i$X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); zuR!,-W  
break; S{aK\>>H  
} MDa 4U@Q  
} dN J2pfvv  
else h{I)^8,M  
break; BKe~ y  
} &^^zm9{  
} *?%DdVrO@  
catch(IOException e){e.printStackTrace ();} #WlIH7J8Tc  
catch(Exception e){e.printStackTrace ();} I:[^><?E  
)xIk#>)  
jD9 ^DzFx  
Utility.log(nFileLength); gy/z;fB  
sF}T9 Ue  
_M= \s>;G  
return nFileLength; dX-Xzg  
} UOy9N  
'+^HeM^;  
Qc-jOl  
//保存下载信息(文件指针位置) _] veTAV  
private void write_nPos()  U=MFNp+  
{ Z?Y14L~%  
try{ Hzh?w!Ow  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wYK-YY:Q3  
output.writeInt(nStartPos.length); !8M]n  
for(int i=0;i<nStartPos.length;i++) smW 7zGE  
{ V9f$zjpw  
// output.writeLong(nPos); .4pWyqU)!  
output.writeLong(fileSplitterFetch.nStartPos); |T0jq  
output.writeLong(fileSplitterFetch.nEndPos); Q1?  !,a  
} Nw'i;}0v7r  
output.close(); e*.l6H/B  
} X*6bsYbK-  
catch(IOException e){e.printStackTrace ();} GV'Y'  
catch(Exception e){e.printStackTrace ();} vK z/-9im  
} mnswG vY  
+G*2f V>  
}stc]L{79  
//读取保存的下载信息(文件指针位置) tWy0% -  
private void read_nPos() -v#0.3zm  
{ 7(AB5.O  
try{ SbI %|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8?AFvua}r  
int nCount = input.readInt(); |u{NM1,  
nStartPos = new long[nCount]; :it52*3=  
nEndPos = new long[nCount]; ] P;Ng=a  
for(int i=0;i<nStartPos.length;i++) 1*<m,.$  
{ jh \L)a*  
nStartPos = input.readLong(); XOK.E&eilj  
nEndPos = input.readLong(); Q[J%  
} Lgl%fO/<t  
input.close(); e>\[OwF-x  
} uuW._$.A>  
catch(IOException e){e.printStackTrace ();} ," ~ew ,  
catch(Exception e){e.printStackTrace ();} c.y8x  
} j4>1a   
Y S )Q#fP  
"pGSz%i-  
private void processErrorCode(int nErrorCode) B*#lkMr  
{ t=\y|Idc  
System.err.println("Error Code : " + nErrorCode);  oZTKG'  
} 45fk+#  
zX{K\yp  
57*`y'C W  
//停止文件下载 X}C }  
public void siteStop() ^Rriu $\  
{ H7!j5^  
bStop = true; A]^RV{P  
for(int i=0;i<nStartPos.length;i++) z)N8#Y~vn  
fileSplitterFetch.splitterStop(); }cuU5WQ?%  
[;yEG$)K  
bC{1LY0  
} r kOLTi[$  
} 1,q&A RTS  
//负责部分文件的抓取 jA9&hbQuL  
**FileSplitterFetch.java uBp"YX9rx  
*/ ea!_/Y  
package NetFox; Ao>] ~r0  
i|A0G%m]$  
9D,`9L5-=  
import java.io.*; D  /wX  
import java.net.*; 2Ur9*#~kGp  
DY| s |:d  
= rDoXm  
public class FileSplitterFetch extends Thread { co^kP##Y  
H]2cw{2  
jinDKJ,n;  
String sURL; //File URL ha_&U@w  
long nStartPos; //File Snippet Start Position #_)<~  
long nEndPos; //File Snippet End Position O3H dPQ  
int nThreadID; //Thread's ID ?QuD:v ck  
boolean bDownOver = false; //Downing is over hJ[Z~PC\T0  
boolean bStop = false; //Stop identical !Wn^B|  
FileAccessI fileAccessI = null; //File Access interface @}sxA9 a  
eiE36+'>b  
b7&5>Q/ g  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException t@dv$W2 "  
{ p2Yc:9r9+A  
this.sURL = sURL; (Q~ p"Ch  
this.nStartPos = nStart; GcXh V  
this.nEndPos = nEnd; _Ec9g^I10  
nThreadID = id; V80BO#Pk  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @,btQ_'X  
} "`;$wA  
AG ?cI@',  
7mG/f  
public void run() J${'?!N  
{ B.)!zv\{  
while(nStartPos < nEndPos && !bStop) 4#jW}4C{  
{ XNODDH   
z^;0{q,  
?4p\ujc  
try{ S3Q^K.e?  
URL url = new URL(sURL); Q7u/k$qN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F\LAw#IJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); (t$jb |Oa  
String sProperty = "bytes="+nStartPos+"-"; O"%b@$p\L  
httpConnection.setRequestProperty("RANGE",sProperty); "9Q @&C  
Utility.log(sProperty); >/W  
k'H+l]=  
0^?:Zds  
InputStream input = httpConnection.getInputStream(); ;h|zNx0  
//logResponseHead(httpConnection); aNd6# yU$  
v D"4aw  
oll J#i9  
byte[] b = new byte[1024]; O{YT6&.S0  
int nRead; -|Z[GN:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O}$@|w(8;  
{ V5ve  
nStartPos += fileAccessI.write(b,0,nRead); 6} b1*xQ  
//if(nThreadID == 1) b@6hGiqx  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {w/{)B nPG  
} 8OV;&Z,x  
W|C>X=zTi  
^r4@C2#vzJ  
Utility.log("Thread " + nThreadID + " is over!"); l~_] k  
bDownOver = true; SQ$|s%)oB  
//nPos = fileAccessI.write (b,0,nRead); gXrXVv<)yw  
} qIXo_H&\C  
catch(Exception e){e.printStackTrace ();} ,# i@jB  
} T9&-t7:  
} 5~BM+ja  
$@WqM$  
Tf0"9  
//打印回应的头信息 H rMH  
public void logResponseHead(HttpURLConnection con) Gcu[G]D  
{ }bkQr)us  
for(int i=1;;i++) Vp"=8p#k  
{ \L6kCY  
String header=con.getHeaderFieldKey(i); k 5~#_D>  
if(header!=null) h`{agW B  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [9}D+k F  
Utility.log(header+" : "+con.getHeaderField(header)); >d/DXv 3  
else W>^WNo3YQ$  
break; & B CA  
} G&2UXr3  
} q$#5>5&  
E[IjeJB5  
h\]D:S  
public void splitterStop() 3u&>r-V6Fn  
{ `1O<UJX  
bStop = true; 397IbZ\  
} l*l?aI  
3vcKK;qCB  
]x;*Z&  
} =I(F(AE  
yUUg8xbpxF  
|IN{8  
/* $ G\IzK  
**FileAccess.java #Qir%\*V  
*//文件访问(定位,写) Ll2yJ .C4  
package NetFox; q:iB}ch5R  
import java.io.*; Bsr; MVD  
Npr<{}ZE  
M/Twtq-`H  
public class FileAccessI implements Serializable{ ON.1'Wk?  
!L|}/u3v  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 lla?;^,  
RandomAccessFile oSavedFile; %1\MW+  
long nPos; "W"2 Y(  
\ytF@"7  
s|cL mL[  
public FileAccessI() throws IOException k'(d$;Jgr  
{ w# iezo. 0  
this("",0); J>o%6D  
} :" ta#g'  
47/14rY 2  
+VE ] .*T  
public FileAccessI(String sName,long nPos) throws IOException 0Z11V9Jk  
{ Q;h6F{i  
oSavedFile = new RandomAccessFile(sName,"rw"); vV(?A  
this.nPos = nPos; }=7? & b  
oSavedFile.seek(nPos); 2:8p>^g=  
} CyHaFUbZ  
t_Q\uo}  
~_XK<}SK  
public synchronized int write(byte[] b,int nStart,int nLen) h?D>Dfeg%  
{ %U<1]  
int n = -1; &/\Q6$a  
try{ l- mt{2  
oSavedFile.write(b,nStart,nLen); 1xf Pe#  
n = nLen; )XFaVkQ}  
} be->ofUYgs  
catch(IOException e) $FJf8u`  
{  << XWL:  
e.printStackTrace (); 9ZYT#h  
} ;A\SbLM  
Y8s.Q  
K{vn[}  
return n; .%x1%TN  
} W Z_yaG$U  
&{gD(QG  
9w"kxAN  
}  mS]&  
ge[hAI2I  
9f|+LN##  
/* F<YXkG4 pO  
**SiteInfoBean.java ||}'  
*/ =N~*`5|rk  
package NetFox; \LEU reTn  
g> <*qd?t  
izvwXC  
public class SiteInfoBean { ';vL j1v  
} G3:QD  
9&O7F}VP2  
private String sSiteURL; //Site's URL ?D,8lABkT  
private String sFilePath; //Saved File's Path >[qoNy;  
private String sFileName; //Saved File's Name qhQeQ  
private int nSplitter; //Count of Splited Downloading File Zr#\>h'c  
&BZjQK  
UG,<\k&  
public SiteInfoBean() \@eaSa  
{//nSplitter的缺省值为5 /=i+7^  
//default value of nSplitter is 5 "NM SLqO  
this("","","",5); gK#G8V-,  
} "C~Zl&3  
<J o\RUx  
@ )2<$d  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "<Q,|Md  
{ >u0B ~9_E  
sSiteURL= sURL; qF? n&>YG  
sFilePath = sPath; 6");NHE  
sFileName = sName; ^77Q4"{W  
this.nSplitter = nSpiltter; _@/nc:)H  
I #bta  
J+:gIszsWT  
} >s;>"]  
?E6 C|A$I  
cq0#~20  
public String getSSiteURL() +\yQZ{4'@  
{ [+2iwfD  
return sSiteURL; M/LC:,  
} Zk*!,,P!  
"T~ce@  
Er!s\(h  
public void setSSiteURL(String value) Rch?@O#J  
{ )1ct%rue  
sSiteURL = value; \-Ipa59U  
} H\^zp5/  
Ty5}5)CRZ  
vd FP ^06  
public String getSFilePath() Q^@z]Sc[  
{ wticA#mb  
return sFilePath; >&?k^nI}J  
} [IRWm N-  
6^#@y|.  
o'*7I|7a  
public void setSFilePath(String value) g?1! /+  
{ c>)_I  
sFilePath = value; _!:*&{  
} Xt$o$V  
C#tY};t  
277Am*2  
public String getSFileName() 7|Bg--G1  
{ 8;q2W F{AX  
return sFileName; C9Xj)5k@R  
} 6 66f;h  
Og E<bw  
vNIQ1x5Za  
public void setSFileName(String value) YCI- p p  
{ Pgo^$xn'6  
sFileName = value; h3BDHz,  
} qP4vH]  
6_a~ 4_#  
<"HbX  
public int getNSplitter() <UE-9g5?G  
{ 3OvQ,^[J4  
return nSplitter; 2(s-8E:  
} ;Svs|]d  
}Q#3\z5  
-8pQI  
public void setNSplitter(int nCount) 6U?z  
{ grbUR)f<?-  
nSplitter = nCount; ?_BK(kL_  
} yRtxh_wr9  
} [7sy}UH  
T^1]|P  
1J?x2  
/* 90[?)s  
**Utility.java & G8tb>q<V  
*/ #Ks2a):8  
package NetFox; =1e>$E#  
Y-y<gW  
9yWQ}h  
public class Utility { R\ZyS )~l  
_I A{I  
e)): U  
public Utility() W"&Y7("y  
{ ITr@;@}c]  
kr{eC/Q"  
^wTod\y  
} xu(N'l.7&  
M9dOLM.  
//线程睡眠 ]O 8hkGa  
public static void sleep(int nSecond) Ce-D^9kC  
{ E@N& Y1t  
try{ se ]q~<&  
Thread.sleep(nSecond); y{O81 7 \  
} p0bMgP  
catch(Exception e) 5* 3T+OK  
{ fXfO9{E  
e.printStackTrace (); l6z}D; 4  
} {wy#HYhv  
} \`N<0COP  
QsC6\Gt#  
//日志  _7P#?:h  
public static void log(String sMsg) rFl6xM;F  
{ n[tES6u  
System.err.println(sMsg); ZT1IN6;8W  
} , I^:xw_  
#a|.cm>6  
uX8yS|= *  
public static void log(int sMsg) ]s<}'&  
{ na-mh E,H  
System.err.println(sMsg); p6|RV(?8  
} MFqM 6_  
} /KLs+^c5  
9n!IdqKN  
}n[<$*W^  
/* k%2Rv4)hU  
**TestMethod.java 2GW.'\D  
*/ OHyBNJ  
package NetFox; ^!yJ;'H\  
ai@hQJ*  
l?J|Ip2W  
public class TestMethod { WIkr0k  
D N#OLk  
V+- ]txu|  
public TestMethod() ON q=bI*  
{ ///xx/weblogic60b2_win.exe *Iir/6myM  
try{ Aat-938FP6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^Z`?mNq9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); lVR a{._m  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [)L)R`  
fileFetch.start(); l.@&B@5F  
} -er8(snDQ  
catch(Exception e){e.printStackTrace ();} Yj/[I\I"m  
,p7W4;?4  
4y|%Oj  
} hQPNxpe  
Ks_B%d  
+204.Yj?D  
public static void main(String[] args) k< i#agq  
{ zd-qQ.j0  
new TestMethod(); >2[nTfS  
} \\{+t<?J  
} RZrQ^tI3"  
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