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http断点续传简单实现(java)

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/* iP~dH/B|v  
**SiteFileFetch.java h8_~ OX  
*/ mg^\"GC*8  
package NetFox; #`H^8/!e  
import java.io.*; wh;E\^',n  
import java.net.*; in6iJ*E@'  
L)ry!BuHI  
#FV(a~  
public class SiteFileFetch extends Thread { o<-+y\J8K  
D`^9 u K  
?V&[U  
SiteInfoBean siteInfoBean = null; //文件信息Bean d\ Z#XzI8  
long[] nStartPos; //开始位置 &Wup 7  
long[] nEndPos; //结束位置 g#ONtY@*U  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F- n1J?4b  
long nFileLength; //文件长度 9jwo f}OU  
boolean bFirst = true; //是否第一次取文件 H;n(qBSB  
boolean bStop = false; //停止标志 S[ ,r .+  
File tmpFile; //文件下载的临时信息 h&6x.ps@  
DataOutputStream output; //输出到文件的输出流 lEC58`Ws  
ai ,Mez  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 6gfdXVN5  
public SiteFileFetch(SiteInfoBean bean) throws IOException cNG6 A4  
{ X7]vXo*  
siteInfoBean = bean; <!vAqqljt  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U q6..<#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n[/|M  
if(tmpFile.exists ()) *7I=vro  
{ s"|N-A=cS  
bFirst = false; !Jj=H()}  
read_nPos(); YtrMJ"  
} VRoeq {  
else a;Y9wn  
{ (Rk g  
nStartPos = new long[bean.getNSplitter()]; LHWh-h(s  
nEndPos = new long[bean.getNSplitter()]; A4?_ 0:<  
} &7X0 ;<  
>:`Y]6z  
Q=9S?p M  
UmU=3et<Wj  
} y*6r&989  
5\tYs=>b<  
yXw xq(32  
public void run() U<NpDjc"  
{ g5to0  
//获得文件长度 \?fl%r2  
//分割文件 EQ>bwEG  
//实例FileSplitterFetch .-N9\GlJ,d  
//启动FileSplitterFetch线程 * #;rp~  
//等待子线程返回 um&e.V)N  
try{ +-#| M|a  
if(bFirst) }h>e=<  
{ w|PZSOJ  
nFileLength = getFileSize(); 4f"a/(>*  
if(nFileLength == -1) ]IJ.}  
{ l(zkMR$b8  
System.err.println("File Length is not known!"); hk&p+NV!  
} nx,67u/Pb  
else if(nFileLength == -2)  N _r*Ig  
{ >|7&hj$  
System.err.println("File is not access!"); zT~ GBC-IX  
} bah5 f  
else Pwz^{*u]  
{ j &Ayk*  
for(int i=0;i<nStartPos.length;i++) i4!n Oyk  
{ (s{%XB:K  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Af0E_  
} 0tB9X9:,  
for(int i=0;i<nEndPos.length-1;i++) Zk}e?Grc  
{ rsP-?oD8)  
nEndPos = nStartPos[i+1]; $b$r,mc  
} yZFv pw|g  
nEndPos[nEndPos.length-1] = nFileLength; 6M$.gX G.  
} Qq]UEI `Go  
} bTHa;* `  
^ I,1kl~i  
xyz-T1ib  
//启动子线程 5 |C;]pq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; XW]|Mv[M  
for(int i=0;i<nStartPos.length;i++) %_SE$>v^  
{ Yjk A^e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }.zgVL L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~rY<y%K  
nStartPos,nEndPos,i); wQnr*kyza  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K{>O. 5  
fileSplitterFetch.start(); ^"+cJ)  
} #8|;Q`Or:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rT}d<c Sf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o`j%$K4?5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", o <l4}~a  
nEndPos = " + nFileLength); J(/ eR,ak  
// fileSplitterFetch[nPos.length-1].start(); oRWsi/Zf  
2#W%--  
)vGRfFjw_  
//等待子线程结束 Qn%*kU0X  
//int count = 0; 5I(` s#O  
//是否结束while循环 ;N"XW=F4e  
boolean breakWhile = false; S%xGXmZ  
[TO:- 8$.  
3y 3 U`Mo  
while(!bStop) ~T4 =Id  
{ Z/x<U.B  
write_nPos(); JG}U,{7(  
Utility.sleep(500); xI:;%5{LN  
breakWhile = true; ( v ~/glf  
Z^GriL  
#2HygS  
for(int i=0;i<nStartPos.length;i++) aeBth{  
{ 1NOz $fW  
if(!fileSplitterFetch.bDownOver) 'OX6e Y5  
{ S-f3rL[?  
breakWhile = false; J;T_ 9  
break; 5K6_#g4"  
} Va*Uwy?x/)  
} s9[v_(W  
if(breakWhile) .=@M>TZM  
break; dqKTF_+VhA  
bh7 1Zu  
& vLX  
//count++; w@%W{aUC  
//if(count>4) ;:$Na=  
// siteStop(); @Qc['V)  
} qo. 6T  
/ V {w<  
0U/:Tpyr  
System.err.println("文件下载结束!"); *iC t4J  
} IG9Q~7@  
catch(Exception e){e.printStackTrace ();} [?IERE!xQ  
} h0^V!.- 5  
caj)  
G0]n4"~+?  
//获得文件长度 10}Zoq|)n  
public long getFileSize() *!s4#|h  
{ z ~VA#8>  
int nFileLength = -1; f1~3y}7^Jq  
try{ [#9ij3vxd  
URL url = new URL(siteInfoBean.getSSiteURL()); BEI/OGp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #JLDj(a?  
httpConnection.setRequestProperty("User-Agent","NetFox"); GO?-z0V  
~l}TlRqL  
%ri4nKGS  
int responseCode=httpConnection.getResponseCode(); BklB3*n  
if(responseCode>=400) xd .I5  
{ O5=ggG  
processErrorCode(responseCode); QOF;j#H^  
return -2; //-2 represent access is error M3t_!HP}!  
} UxS;m4  
o"]eAQ  
=AKW(v  
String sHeader; ^g[])2",  
+pcj8K%  
HRb_ZJz  
for(int i=1;;i++) %cm5Z^B1"  
{ a<Ns C1  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .y\HQ^j  
//Utility.log(in.readLine()); Maa.>2v<  
sHeader=httpConnection.getHeaderFieldKey(i); rL,)Tc|"  
if(sHeader!=null) ;Q"F@v}18  
{ (%P* rl  
if(sHeader.equals("Content-Length")) `riv`+J{s  
{ H_AV3 ;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); VG8rd'Z  
break; O\D({>  
} |@@mq!>-  
} ./fEx 'E  
else C3b'Q  
break; y\S7oD(OR  
} bL&]3n9Rwu  
} )Xh_q3=  
catch(IOException e){e.printStackTrace ();} 9e1 6 g  
catch(Exception e){e.printStackTrace ();} AngECkF-  
-pD&@Wlwak  
gOWyV@  
Utility.log(nFileLength); mhVoz0%1X  
| 5L1\O8#  
t~a$|( 9  
return nFileLength; .y0]( h  
} n5JB'F)  
-E500F*b  
NuooA  
//保存下载信息(文件指针位置) c df ll+  
private void write_nPos() g~y9j88?  
{ apMYBbC  
try{ 2?r8>#_*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); r2](~&i2  
output.writeInt(nStartPos.length); fM|g8(TK,  
for(int i=0;i<nStartPos.length;i++) bK].qN  
{ : te xl  
// output.writeLong(nPos); 6>L.)V  
output.writeLong(fileSplitterFetch.nStartPos); tZ@ +18  
output.writeLong(fileSplitterFetch.nEndPos); ^ 2AF:(E  
} D}061~zb$  
output.close(); _5K_YhT  
} k,@J&   
catch(IOException e){e.printStackTrace ();} 1IlR  
catch(Exception e){e.printStackTrace ();} O\LW 8\M  
} =k*0O_  
R`* *!ku  
#PrV)en  
//读取保存的下载信息(文件指针位置) wr$}AX  
private void read_nPos()  g_>ZE  
{ vW{cB y  
try{ tT8jC:oVa  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _$'Mx'IC=  
int nCount = input.readInt(); J@GfO\ o  
nStartPos = new long[nCount]; fD~!t 8J  
nEndPos = new long[nCount]; #LN I&5  
for(int i=0;i<nStartPos.length;i++) 7XDV=PQ[  
{ psZeu*/r  
nStartPos = input.readLong(); bF KP V%`  
nEndPos = input.readLong(); jccW8g~ ~  
} +_g T|vlU  
input.close(); jSFN/C.9h  
} )T64(_TE  
catch(IOException e){e.printStackTrace ();} {IMzR'PN  
catch(Exception e){e.printStackTrace ();} 0lRH Yu  
} pq[mM!;#v  
w}.'Tebu  
:xw3b)KS  
private void processErrorCode(int nErrorCode) I:e2sE ":  
{ ^c\IZ5  
System.err.println("Error Code : " + nErrorCode); ?:?4rIZ<  
} @"I#b99  
;ULC|7rL  
' 4~5ez|:  
//停止文件下载 H<;Fb;b  
public void siteStop() *!'&:  
{ mU=6"A0 U  
bStop = true; +2zuIW.  
for(int i=0;i<nStartPos.length;i++) Ib2@Wi   
fileSplitterFetch.splitterStop(); xplo Fw~  
s3M84wz  
x ct U.)p  
} gFT~\3j p=  
} t%U[\\ic  
//负责部分文件的抓取 CJ?gjV6  
**FileSplitterFetch.java m"G N^V7  
*/ PEBFN  
package NetFox; q~J oGTv  
Z% ;4Ed  
>'6GcnEb4.  
import java.io.*; Nr"N\yOA/  
import java.net.*; -m160k3  
aE BP9RX}z  
{F :v$ K  
public class FileSplitterFetch extends Thread { iw fp'  
YC]YX H  
}%YHm9)  
String sURL; //File URL 4VNb`!e  
long nStartPos; //File Snippet Start Position }Hz-h4Z  
long nEndPos; //File Snippet End Position Q$)|/Y))  
int nThreadID; //Thread's ID $a\Uv0:xRx  
boolean bDownOver = false; //Downing is over @E}X-r.^f  
boolean bStop = false; //Stop identical VK'T[5e  
FileAccessI fileAccessI = null; //File Access interface A'( 7VJ  
*yaX:,'\$  
.gN$N=7<  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _GO+fB/Q1  
{ u`pROd/ R5  
this.sURL = sURL; {(OIu]:  
this.nStartPos = nStart; e5ru:#P.p  
this.nEndPos = nEnd; *>'2$me=  
nThreadID = id; h)_Gxe"x  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 sJb)HQ,7x  
} DAnb.0  
8},<e>q  
T;4` wB8@  
public void run() A,gx5!J  
{ }{8Fo4/  
while(nStartPos < nEndPos && !bStop) HB7(  
{ D4q >R;  
YvruK: I  
bW9"0=j[{  
try{ lB!vF ~A&  
URL url = new URL(sURL); ~g1, !Wl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X B*}P  
httpConnection.setRequestProperty("User-Agent","NetFox"); m*!f%}T  
String sProperty = "bytes="+nStartPos+"-"; ^$IZLM?E~  
httpConnection.setRequestProperty("RANGE",sProperty); 14D 7U/zer  
Utility.log(sProperty); *w/WHQ`xI  
_;:rkC fj  
8rwYNb.P  
InputStream input = httpConnection.getInputStream(); lKEX"KQ!  
//logResponseHead(httpConnection); ~pevU`}Uqc  
^5]u BOv  
N\q)LM !M  
byte[] b = new byte[1024]; iS"8X#[]N  
int nRead; uyNJN  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Vd +Q:L  
{ <'[Ku;m  
nStartPos += fileAccessI.write(b,0,nRead); d;~ 3P  
//if(nThreadID == 1) =dM.7$6) R  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m1-\qt-yy  
} -+}5ma  
Ud#X@xK<h  
rKzlK 'U  
Utility.log("Thread " + nThreadID + " is over!"); P>Q{He:  
bDownOver = true; 85D^@{  
//nPos = fileAccessI.write (b,0,nRead); q[G/}  
} #9`rXEz  
catch(Exception e){e.printStackTrace ();} (`6%og#8  
} B:-U`CHHQ  
} -@2'I++"@  
A)Qh  
Kej|1g1f  
//打印回应的头信息 Y}LLOj@L  
public void logResponseHead(HttpURLConnection con) ~XUOWY75  
{ 0||"r&:X  
for(int i=1;;i++) 4;C*Fa  
{ $_C+4[R?  
String header=con.getHeaderFieldKey(i); _1sMYhI  
if(header!=null) L)F1NuR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'j,oIqx  
Utility.log(header+" : "+con.getHeaderField(header)); +2DE/wE]e+  
else BWUt{,?KU  
break; j1YH9T#|D  
} o\ngR\>  
} py{eX`(MS  
x _==Ss  
)nwZ/&@  
public void splitterStop() H&X:!xa5  
{ A Jyq>0p  
bStop = true; aDL)|>"Q  
} [ $l"-*s4  
%bP~wl~  
`c"4PU^  
} k6Ihc?HL  
d/{Q t  
53 @oP  
/* (*,8KLV_i  
**FileAccess.java 7DtIVMiK  
*//文件访问(定位,写) <%z@  
package NetFox; -Z%F mv8  
import java.io.*; u7;`4P:o@  
99e*]')A%  
6&89~W{  
public class FileAccessI implements Serializable{ 3;*z3;#}  
?7 #7:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6b?`:$Cw3)  
RandomAccessFile oSavedFile; <EMkD1e  
long nPos; =m}TU)4.  
 I>A^I  
]gu1#  
public FileAccessI() throws IOException 6Rcu a<;2P  
{ ~TDzq -U)  
this("",0); 4`nqAX~'f  
} ?6i;)eIOI  
L=,OZ9aA  
}YQ:6I  
public FileAccessI(String sName,long nPos) throws IOException &=6%>  
{ <cYp~e%xIw  
oSavedFile = new RandomAccessFile(sName,"rw"); &hayR_F9  
this.nPos = nPos; cd!|Ne>fe  
oSavedFile.seek(nPos); W57&\PXYn  
} kMy<G8 s  
2H[ ; v+  
{Eu'v$c!  
public synchronized int write(byte[] b,int nStart,int nLen) T2wv0sHlt  
{ {XtoiI  
int n = -1; ~r<p@k=.#0  
try{ q7,^E`5EgU  
oSavedFile.write(b,nStart,nLen); <_9!  
n = nLen; s~^*+kq  
} 6xHi\L  
catch(IOException e) :zlpfm2  
{ Ah-8"`E  
e.printStackTrace (); xf/m!b"p  
} Fn!SGX~kx$  
Z,WubX<  
%e{(twp  
return n; f =o4I2Y[  
} <Nex8fiJ9  
pI>*u ]x  
"u;YI=+  
} vM`7s[oAK  
JSgpb ?(  
0Uw ^FcW  
/* WSLy}@`Vx  
**SiteInfoBean.java :uo[&&c  
*/ EKuSnlTXba  
package NetFox;  %[`a  
3_W{T@T  
vZ@g@zB4o0  
public class SiteInfoBean { XJSa]P^B1  
R}r~p?(M  
/b#q*x-b  
private String sSiteURL; //Site's URL zDDK  
private String sFilePath; //Saved File's Path P16YS8$  
private String sFileName; //Saved File's Name )~V }oKk0t  
private int nSplitter; //Count of Splited Downloading File 5Z{_m;I.   
jWvtv ng  
B'}"AC"  
public SiteInfoBean() +8AvTSgX%  
{//nSplitter的缺省值为5 *Y%Jl o  
//default value of nSplitter is 5 n'K6vW3  
this("","","",5); FLZSK:3B]  
} =&7@<vBpy  
=i>\2J%'R  
_s+c+]bO  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;cKH1  
{ ;W{b $k@g  
sSiteURL= sURL; MzzKJ;wbC6  
sFilePath = sPath; ^e%}[q[>|  
sFileName = sName; p@ygne 4  
this.nSplitter = nSpiltter; r`6:Q&&  
5& !'^!  
8o|P&q(v*  
} ,Ff n)+  
gn ?YF`  
k4{:9zL1#?  
public String getSSiteURL() B +Aj*\Y.  
{ J8<J8x4  
return sSiteURL; _D,eyP9P  
} +xp]:h|  
| o0RP|l  
*C6D3y  
public void setSSiteURL(String value) :#u}.G  
{ r_U>VT^E:  
sSiteURL = value; uS<_4A;sD,  
} $^_|j1 z#i  
p|qyTeg  
CzVmNy)kl  
public String getSFilePath() KX3KM!*  
{ `8:Kp  
return sFilePath; $`ztiVu3  
} ?6P.b6m}0  
jL>:>r  
8W+5)m.tp  
public void setSFilePath(String value) 2) ?q 58  
{ t-7og;^8k  
sFilePath = value; j~`\XX{>  
} {]kaJ{U>  
U)D[]BVg  
-5b A $  
public String getSFileName() rmd;\)#*`  
{ P)6 lu8zQ  
return sFileName; 0$HmY2 Men  
} .DguR2KT  
Vz%OV}\  
\9:wfLF8!  
public void setSFileName(String value) 4=[7Em?oLb  
{ x/mp=  
sFileName = value; L{8;Ud_2r  
} $_D6_|HK  
6f)2F< 7  
 HpW 42  
public int getNSplitter() SVWIEH0?  
{ #sB,1"  
return nSplitter; 9&Ne+MY^%  
} d]wD[]  
86qI   
PmX2[7  
public void setNSplitter(int nCount) sL^yB  
{ < <Y}~N  
nSplitter = nCount; +K~NV?c  
} ^,8R,S\} $  
} Bh]!WMAw.  
'Ot,H_pE  
Yu3zM79'k  
/* ~i~%~doa  
**Utility.java @jy41eIo  
*/ K#mOSY;}  
package NetFox; \7v)iG|#G&  
QM<y`cZ8  
.Y*f2A.v  
public class Utility { aP-<4uGx  
S* R,FKg  
7 s Fz?` -  
public Utility() y$W|~ H   
{ V@vU"  
J CGC  
Y&.UIosWb  
} w:i:~f .  
Q<(YP.k  
//线程睡眠 e Y$qV}  
public static void sleep(int nSecond) Uh6 '$0  
{ 1B=>_3_  
try{ ,*svtw:2')  
Thread.sleep(nSecond); ExBUpDQc  
} 8wZf ]_  
catch(Exception e) PWr(*ZP>hI  
{ =8{WZCW5  
e.printStackTrace (); +A8j@d#:  
} MGpt}|t-  
} _BM4>r?\  
f3MRD4+-  
//日志 &&> tf%[  
public static void log(String sMsg) 0(TTw(;  
{ RFaSwf,5n  
System.err.println(sMsg); Cby;?F6w  
} B%s7bS  
U7 @AC}.+  
t= #&fSR  
public static void log(int sMsg) =EP13J  
{ K=::)/{P  
System.err.println(sMsg); 6xK[34~ 6  
} <Zb/  
} H}}$V7]^),  
O[^%{'  
oqd;6[%G  
/* _qwQ;!9  
**TestMethod.java ;,h/   
*/ %ysZ5:X  
package NetFox; CY:d`4  
~uWOdm-"[  
13k !'P  
public class TestMethod { !^oV #  
kOwMs<1J  
g=L]S-e  
public TestMethod() 1c4/}3*  
{ ///xx/weblogic60b2_win.exe DOS0;^f  
try{ 0|4%4 Mt  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); hwYQGtjF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); op2Of<{h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); F9"w6;hh  
fileFetch.start(); xM>W2  
} _ gj&$zP  
catch(Exception e){e.printStackTrace ();} ;*TIM%6#  
S[3iA~)Z-  
XN=67f$Hw  
} ,_.I\EY[  
}Db[ 4  
3g'S\ G@  
public static void main(String[] args) %8~Q!=*Iq  
{ {P%9  
new TestMethod(); u7%D6W~m0  
} IY'=DePd  
} `>Tu|3%\  
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