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http断点续传简单实现(java)

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/* H}@|ucM"\  
**SiteFileFetch.java ! of7]s  
*/ 54OYAkPCk  
package NetFox; V|D;7  
import java.io.*; nJ?C4\#3  
import java.net.*; >YW>=5_  
-`;8~wMN  
_+. t7q^  
public class SiteFileFetch extends Thread { u,pm\  
{NFeX'5bP  
y, Z#? O  
SiteInfoBean siteInfoBean = null; //文件信息Bean =#u2Rx%V  
long[] nStartPos; //开始位置 h1Lp:@:|  
long[] nEndPos; //结束位置 \uYUX~}i"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >hhd9  
long nFileLength; //文件长度 646ye Q1  
boolean bFirst = true; //是否第一次取文件 M&K@><6k,k  
boolean bStop = false; //停止标志 ! Q#b4f  
File tmpFile; //文件下载的临时信息 l:ED_env:  
DataOutputStream output; //输出到文件的输出流 _5)#{ o<  
M{S7ia"s  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 0{ ,zE  
public SiteFileFetch(SiteInfoBean bean) throws IOException s%:fB(  
{ Vy9n3W"FB1  
siteInfoBean = bean; vW_A.iI"e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %,^7J;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <|8 l;  
if(tmpFile.exists ()) }J*&()`  
{ ^4[\-L8Lpq  
bFirst = false; GBQb({  
read_nPos(); bXW)n<y  
} 9j 8t<5s  
else OBl8kH(b>  
{ ZMe|fn  
nStartPos = new long[bean.getNSplitter()]; {7wvC)WW  
nEndPos = new long[bean.getNSplitter()]; ky#6M? \  
} e\dT~)c  
sV6A& Aw  
w0IB8GdF  
y((_V%F}  
} WY,t> 1c  
@v'D9 ?  
I>xB.$A  
public void run() 4"2/"D0  
{ <\8   
//获得文件长度 =oTYwU  
//分割文件 U&5zs r  
//实例FileSplitterFetch W wE)XE  
//启动FileSplitterFetch线程 WU4i-@Bm8  
//等待子线程返回 sHuz10  
try{ V588Leb?  
if(bFirst) b[k 1)R"  
{ GlZ9k-ZRF  
nFileLength = getFileSize(); [E^X=+Jnz  
if(nFileLength == -1) g-^m\>B  
{ oD7H6\_  
System.err.println("File Length is not known!"); oL@ou{iQ  
} -7$'* V9$  
else if(nFileLength == -2) ]~zJ7I  
{ h=tu +pn  
System.err.println("File is not access!"); 16y$;kf8  
} c-T ^ aR  
else gh}AD1TN]  
{ >(rB[ZJ  
for(int i=0;i<nStartPos.length;i++) ^;3rdBprm  
{ CJOl|"UyJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]aRD6F:L  
} `|w#K28t"  
for(int i=0;i<nEndPos.length-1;i++) +m.8*^  
{ ) T1 oDk  
nEndPos = nStartPos[i+1]; *N r|G61  
} >FHsZKJ  
nEndPos[nEndPos.length-1] = nFileLength; Fdw[CYHz  
} ."X~?Nk  
} Yel(}Ny  
2P ?Iu&  
>>cd3)b  
//启动子线程 h6e$$-_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; rsv!mY,Em  
for(int i=0;i<nStartPos.length;i++) r8%,xA&  
{ C6M/$_l&a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `.W;ptZ6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), DxgT]F%  
nStartPos,nEndPos,i); gk1S"H  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); orHD3T%&  
fileSplitterFetch.start(); 5r<(Z0  
} j*u9+.   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0_ \ g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); h /QP=Zd  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", uq%3;#[0  
nEndPos = " + nFileLength); Nj_sU0Dt  
// fileSplitterFetch[nPos.length-1].start(); C<t>m_t9  
m#$za7  
}?J5!X  
//等待子线程结束 RM1uYFs<  
//int count = 0; CD1=2  
//是否结束while循环 _0["J:s9  
boolean breakWhile = false; /A.i5=k  
/&:9VMMj  
UMwMXmZNJ  
while(!bStop) ~ p.W*skD  
{ dO;vcgvb  
write_nPos(); &i^NStqu  
Utility.sleep(500);  &n.uNe  
breakWhile = true; ]~Vu-@ /}  
SWsv,  
8 ysK VF  
for(int i=0;i<nStartPos.length;i++) &] F|U3  
{ W+ '}O<  
if(!fileSplitterFetch.bDownOver) >Mz|e(6  
{ J<#`IaV  
breakWhile = false; SzlfA%4+GR  
break; F6c[v|3  
} ONq/JW$?LV  
} o;>3z*9?3  
if(breakWhile) 0,$-)SkT  
break; x5z4Yv^ m  
OG+r|.N;  
CPNN!%-  
//count++; v6-~fcX0G  
//if(count>4) ' xZPIj+  
// siteStop(); Hq\E 06S@  
} M|#5gKXd  
Z)i1?#  
([CnYv  
System.err.println("文件下载结束!"); ]|t.wr3AU  
} Y+u-J4bj  
catch(Exception e){e.printStackTrace ();} UxcDDa/j2T  
} {dA ~#fW<  
BH0#Q5  
LL[#b2CKa  
//获得文件长度 MupW=3.38  
public long getFileSize() C$td{tM  
{ 7;}3{z  
int nFileLength = -1; Y-3[KHD  
try{ Ipz 1+ #s'  
URL url = new URL(siteInfoBean.getSSiteURL()); d6@jEa-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #O9*$eMw  
httpConnection.setRequestProperty("User-Agent","NetFox"); k\c &2T]W  
<%>n@A  
-iDEh_pts  
int responseCode=httpConnection.getResponseCode(); b({Nf,(a2  
if(responseCode>=400) RD$tc~@UB  
{ >@^yj+k  
processErrorCode(responseCode); 4%fN\f  
return -2; //-2 represent access is error ]6B mCh  
} @>Ghfh>~D  
&:;;u\  
f;Bfh3  
String sHeader; .eabtGO,  
R=amKLD?  
4-+ozC{  
for(int i=1;;i++) ,M@m4bx  
{ nKh%E-c  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); xZP>g  
//Utility.log(in.readLine()); 5hJYy`h~  
sHeader=httpConnection.getHeaderFieldKey(i); (9KDtr*(2i  
if(sHeader!=null) =(.mf  
{ Rnj Jg?I=  
if(sHeader.equals("Content-Length")) 5fegWCJ  
{ -4vHK!l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); YBtq0c  
break; "y~muE:.  
} "$W|/vD+  
} q: TT4MUj<  
else b =K6IX;  
break; 9iGE`1N%E  
} &Mhv XHI  
} [ZKtbPHb  
catch(IOException e){e.printStackTrace ();} GX7 eRqz>  
catch(Exception e){e.printStackTrace ();} 2q- :p8  
sb}K%-  
(ET ;LH3  
Utility.log(nFileLength); P /c Q1  
Zk/' \(5  
*(d6Z#  
return nFileLength; s%N`  
} Mhv1K|4s  
}fJ:wku  
rnn2u+OG   
//保存下载信息(文件指针位置) Y ]~ HAv '  
private void write_nPos() ]27>a"p59Y  
{ FJa[ToZ4+  
try{ :BL'>V   
output = new DataOutputStream(new FileOutputStream(tmpFile)); I|KY+k> /  
output.writeInt(nStartPos.length); s- ,=e  
for(int i=0;i<nStartPos.length;i++) `Di ^6UK(  
{ C#U< k0R  
// output.writeLong(nPos); z^gQ\\,4  
output.writeLong(fileSplitterFetch.nStartPos); nDHHYp  
output.writeLong(fileSplitterFetch.nEndPos); H.YIv50E  
} 5q5 )uv"  
output.close(); L_THU4^j  
}  xFBh?  
catch(IOException e){e.printStackTrace ();} {{V ;:+62  
catch(Exception e){e.printStackTrace ();} 6R1wn&8  
} r6d0x  
3>-[B`dD(  
ydwK!j0y  
//读取保存的下载信息(文件指针位置) T} n N=Q4  
private void read_nPos() ,|T*|2Gm  
{ MU_!&(X_  
try{ J)9 AnGWe  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wGEWr2$  
int nCount = input.readInt(); = EQN-{#  
nStartPos = new long[nCount]; 5f;n<EP y  
nEndPos = new long[nCount]; e >L5.~i  
for(int i=0;i<nStartPos.length;i++) q';&SR#"`K  
{ :3f-9aRC!  
nStartPos = input.readLong(); S~+O` y^  
nEndPos = input.readLong(); E2^ KK:4s  
} Uc_jQ4e_  
input.close(); B#FHf Z  
} 9#v-2QY  
catch(IOException e){e.printStackTrace ();} F>(qOH.I  
catch(Exception e){e.printStackTrace ();} E rr4 %-  
} <Z{vC  
:PgF  
7JbY}@  
private void processErrorCode(int nErrorCode) =nJ{$%L\x,  
{ B$cOssl  
System.err.println("Error Code : " + nErrorCode); 89hF )80  
} 2dHM  
u?Fnln e4@  
Oo FgQEr@  
//停止文件下载 &MCy.(jN  
public void siteStop() L +L 9Y}  
{ ;tJWOm  
bStop = true; T"n{WmVQ  
for(int i=0;i<nStartPos.length;i++) -glugVq  
fileSplitterFetch.splitterStop(); Rw{$L~\  
IikG /8lP  
V?OuIg%=:  
} :1:3Svb<Y  
} 8]S,u:E:N  
//负责部分文件的抓取 3^{8_^I  
**FileSplitterFetch.java }1 $hxfb  
*/ + c`AE  
package NetFox; AT"!{Y "H  
Vwjk[ DOL  
ov8 ByJc  
import java.io.*; ? Phk~ jE  
import java.net.*; kW#S]fsfU  
q[-|ZA bbr  
n'T He|:I  
public class FileSplitterFetch extends Thread { N? M   
b`$yqi<[  
0s1'pA'  
String sURL; //File URL G3G/ xC"  
long nStartPos; //File Snippet Start Position e|yX QTlvL  
long nEndPos; //File Snippet End Position J0=7'@(p  
int nThreadID; //Thread's ID UcgG  
boolean bDownOver = false; //Downing is over rVY?6OMkd  
boolean bStop = false; //Stop identical t{!/#eQC  
FileAccessI fileAccessI = null; //File Access interface )IQ*  
X:>$ 8^gS  
`)T&~2n  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >QXzMN}o  
{ _IWxYp  
this.sURL = sURL; 2d-{Q 8Pi  
this.nStartPos = nStart; tE@FvZC'=  
this.nEndPos = nEnd; l';pP^.q  
nThreadID = id; <j;]!qFR  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ',GV6kt_k  
} o7.e'1@  
$*k)|4  
^ oYPyk`9  
public void run() %;7.9%  
{ z 5'ZN+  
while(nStartPos < nEndPos && !bStop) X/l;s  
{ o+NMA (  
mb&lCd ^-  
wqUQ"d  
try{ w!\3ICB  
URL url = new URL(sURL); n0Go p^3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3)3Hck  
httpConnection.setRequestProperty("User-Agent","NetFox"); KF+mZB  
String sProperty = "bytes="+nStartPos+"-"; @D)Z{=>{=5  
httpConnection.setRequestProperty("RANGE",sProperty); L7]]ZAH!1  
Utility.log(sProperty); pE2QnNr'  
Ea-bC:>  
4jQ'+ 2it  
InputStream input = httpConnection.getInputStream(); 61} i5o  
//logResponseHead(httpConnection); /t*YDWLg  
&f-hG3/M  
ND5$bq Nu?  
byte[] b = new byte[1024]; \@K~L4>  
int nRead; gw^'{b  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tmO`|tn&  
{ +TH3&H5I_A  
nStartPos += fileAccessI.write(b,0,nRead); 6g"C#&{@  
//if(nThreadID == 1) ?R|th Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W m . }Zh  
} }x:0os  
-p`L% xj\  
4J5pXlzV  
Utility.log("Thread " + nThreadID + " is over!"); FbAW_Am(  
bDownOver = true; <C'Z H'p  
//nPos = fileAccessI.write (b,0,nRead); v`x|]-/M&  
} g\Ak;03n  
catch(Exception e){e.printStackTrace ();} 9C/MRmv`  
} v>H=,.`0\  
} D<bI2  
G(/DtY]  
aE)by-'  
//打印回应的头信息 T/l1qcf`wT  
public void logResponseHead(HttpURLConnection con) Lg4YED9#  
{ /ylc*3e'4  
for(int i=1;;i++) {:bN/zV#  
{ 0}]SUe^  
String header=con.getHeaderFieldKey(i); uFG<UF  
if(header!=null) gzf-)J  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]]2k}A[-I  
Utility.log(header+" : "+con.getHeaderField(header)); 5dl,co{q  
else QB&BTT=!  
break; T_LLJ}6M  
} $'{=R 45Z  
} jn JZ# =)  
]a?bzOr,  
$shp(T,q  
public void splitterStop() X:EEPGE  
{ (RE2I  
bStop = true; Q9c)k{QZ  
} #H~_K}Ks  
\S ."?!U  
P|xG\3@Z  
} O)]v;9oER  
Xgat-cy'DA  
[&#/|zH'j:  
/* =sgdkAYwP  
**FileAccess.java <41ZZ0<EwY  
*//文件访问(定位,写) NmpnJu|8  
package NetFox; [=uIb._Wv  
import java.io.*; eKG2*CV  
/Vww?9U;  
%w ) +V  
public class FileAccessI implements Serializable{ z-r2!^q27  
r2\c'9uH  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -Q"hZ9  
RandomAccessFile oSavedFile; Fky?\ec  
long nPos; D-&a n@  
]s_8A`vm  
H'DVwnn>ik  
public FileAccessI() throws IOException ,<` )>2 'o  
{ )OP){/   
this("",0); 8e&p\%1  
} S,{tV=&m]  
s{}]D{bc  
*if`/N-q(m  
public FileAccessI(String sName,long nPos) throws IOException C vDxq:x  
{ 6RoAl$}'  
oSavedFile = new RandomAccessFile(sName,"rw"); =qu(~]2(  
this.nPos = nPos; w7TJv4_  
oSavedFile.seek(nPos); vScjq5 "p  
} r!GW= u'  
8b(!k FxD  
7DD&~ZcD  
public synchronized int write(byte[] b,int nStart,int nLen) "_1)CDqP  
{ J G$Z.s  
int n = -1; )[Z!*am  
try{ [?0d~Q(R#  
oSavedFile.write(b,nStart,nLen); F3M aqr y  
n = nLen; j;0vAf  
} G`0V)S  
catch(IOException e) 3=mr "&]r:  
{ 8LzBh_J?  
e.printStackTrace (); ?-)I+EAnE  
} Na{Y}0=^y  
L2UsqVU  
1q7tiMvV-  
return n; ino:N5&;;  
} UL$}{2N,_  
 #xh_  
Vvp[P >  
} 4rg2y]  
3uWkc3  
}H> ^o9  
/* tq1CwzRX  
**SiteInfoBean.java > L2HET  
*/ IxZb$h[  
package NetFox; V)ig)(CT  
Y f@e=:  
L{-LX= G^  
public class SiteInfoBean { =c.5874A`  
fWnD\mx?0  
QS[L~97m2M  
private String sSiteURL; //Site's URL $'rG-g!f\  
private String sFilePath; //Saved File's Path w"Y` ]2  
private String sFileName; //Saved File's Name RE2&mYt  
private int nSplitter; //Count of Splited Downloading File 58Xzup_"  
e'%v1-&sP  
"qz3u`[o  
public SiteInfoBean() rwLAW"0Qz  
{//nSplitter的缺省值为5 B;>{0 s  
//default value of nSplitter is 5 K<`osdp=&  
this("","","",5); `F YjQ e"p  
} =@&cHY  
DyJ.BQdk)  
AlE8Xu9UB  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \_V-A f{6  
{ / P|fB]p  
sSiteURL= sURL; dO> VwP  
sFilePath = sPath; '7^M{y/dU  
sFileName = sName; RD7^&  
this.nSplitter = nSpiltter; sUJ%x#u}Fk  
`.jzuX  
b//B8^Eong  
} %ts^Z*3u  
2Y\ d<.M  
{9Y+.46S  
public String getSSiteURL() -VxTx^)>  
{ 4fk8*{Y  
return sSiteURL; y;w x?1)  
} U4f5xUY0)  
!* Ti}oIo&  
g9D^)V  
public void setSSiteURL(String value) 9vUO *D  
{ !U9|x\BqJ2  
sSiteURL = value; h,aAw#NE*  
} v\16RD  
O/AaYA&  
xsd_Uu*  
public String getSFilePath() (wDm*bZ*  
{ voP7"Dl[  
return sFilePath; wN1niR'  
} |8> 3`w!  
[[PEa-992  
poGc a1  
public void setSFilePath(String value) !tfb*@{;'  
{ ;c~cet4  
sFilePath = value; S#)Eom?V  
} /Jf.y*;  
L^2FQti>  
B~o\+n  
public String getSFileName() wW>zgTG  
{ xh7cVE[UM  
return sFileName;  ]#7zk9  
} }bY; q-  
jK \T|vGJa  
VE+IKj!VG0  
public void setSFileName(String value) &%})wZ+Dj  
{ m'P1BLk  
sFileName = value; J)P$2#  
} JJ;[,  
zi`b2h  
| N0Z-|  
public int getNSplitter() ;};wq&b#  
{ lY|Jr{+Ln  
return nSplitter; U2uF&6v  
} }*.0N;;C  
*K> l*l(f]  
=]:>"_jN  
public void setNSplitter(int nCount) GKN%Tv:D_  
{ GpZ c5c  
nSplitter = nCount; !Mi;*ZR  
} f|O{#AC  
} o-}R?>  
:ba5iMa  
2M# r]  
/* 3nZo{p:E  
**Utility.java ,%\o4Rc'o  
*/ t#q<n:WeYU  
package NetFox; pZ/>[TP(%F  
': N51kC  
FQ g~l4WX  
public class Utility { O_Oj|'bBC  
ZPbpp@,  
nstUMr6  
public Utility() yAoe51h?  
{ LpR3BP@At  
`rf_7  
w)Covz'uf  
} @V03a )6,h  
Eb=}FuV  
//线程睡眠 ^Z:~91Tv-_  
public static void sleep(int nSecond) rn<PR*  
{ H$I =W>;  
try{ L!=QR8?@E  
Thread.sleep(nSecond); fk_o@ G!0  
} 5nsq[Q`  
catch(Exception e) ]Dw]p! @  
{ 6/rFHY2q  
e.printStackTrace (); X7s `U5'l  
} mEG#>Gg$  
} ) /z@vY  
Mn)@{^  
//日志 mdRU^n  
public static void log(String sMsg) jQ:OKh<Y  
{ d/i`l*  
System.err.println(sMsg); &197P7&o  
} =}.EY iD  
m 9/}~Y#k  
m=YU2!Mb  
public static void log(int sMsg) K_dOq68_  
{ DZi!aJ  
System.err.println(sMsg); o865 (<p  
} 5}`_x+$%(`  
} M)U{7c$c7  
dPhQ :sd>  
-|E!e.^7:  
/* OoWyPdC+P  
**TestMethod.java .k,kTr$ S  
*/ )I3NeKWz  
package NetFox; ?Wz8[u  
EVoE szR  
TYy.jFT-  
public class TestMethod { V{JAB]?^  
6L)%T02C  
-;'1^  
public TestMethod() R) c'#St  
{ ///xx/weblogic60b2_win.exe 3D2E?$dX  
try{ U~pV)J  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P>Ez'C  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?mwD*LN3o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 92EWIHEWZ  
fileFetch.start(); Z?\2F%  
} }mAa}{_  
catch(Exception e){e.printStackTrace ();} ~$~5qwl  
p\<u6v ~J  
%"P,1&\^  
} Dc_yM  
kXf'5p1  
1PpyVf  
public static void main(String[] args) qzTuxo0B  
{ )a-Du$kd  
new TestMethod(); "sG=wjcw^  
} ariLG [:X  
} nJo`B4'U  
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