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http断点续传简单实现(java)

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/* .B 2?%2S  
**SiteFileFetch.java 2R9AYI  
*/ 533n z8&9@  
package NetFox; E"d\N-I  
import java.io.*; WAr;g?Q8  
import java.net.*; t^eWFX  
mS?.xu  
I(LBc  
public class SiteFileFetch extends Thread { h| q!Qsnj'  
lAjP'(  
6mcxp+lm|  
SiteInfoBean siteInfoBean = null; //文件信息Bean _}MO.&Y  
long[] nStartPos; //开始位置 ZH'- >/  
long[] nEndPos; //结束位置 VB 53n'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h'*>\eC6  
long nFileLength; //文件长度 ZlaU+Y(_[  
boolean bFirst = true; //是否第一次取文件 j8Nl'"  
boolean bStop = false; //停止标志 wz1fx>Q  
File tmpFile; //文件下载的临时信息 `/]Th&(5  
DataOutputStream output; //输出到文件的输出流 Ky"]L~8$  
(-k`|X"  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 1, 5"sQ$  
public SiteFileFetch(SiteInfoBean bean) throws IOException Gk~QgD/Pix  
{ kLc}a5;  
siteInfoBean = bean; %eJolztKZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z&fXxp  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); R9=K/  
if(tmpFile.exists ()) 0\fV'JDOR  
{ k?(x}IZdG  
bFirst = false; Dn{ hU $*  
read_nPos(); )qXl8HI  
} .Up\ 0|b  
else u,h,;'J  
{ Ns?qLSN  
nStartPos = new long[bean.getNSplitter()]; L~x PIu  
nEndPos = new long[bean.getNSplitter()]; qg521o$*  
} X|o;*J](  
:r5DR`Rfm  
yGGQ;!/  
$|J16tW  
} 5/U|oZM"  
{NmpTb  
<'s_3AC  
public void run() s?qRy 2  
{ %V r vu5  
//获得文件长度 ahezDDR-.i  
//分割文件 e,j2#wjor  
//实例FileSplitterFetch F_28q15~:  
//启动FileSplitterFetch线程 LOm*=MVex  
//等待子线程返回 ]J<2a`IK!  
try{ ZR|)+W;  
if(bFirst) q. zBm@:  
{ 2hZ>bg  
nFileLength = getFileSize(); KDx~^OO  
if(nFileLength == -1) j_=A)B?  
{ \}CQo0v  
System.err.println("File Length is not known!"); |%wgux`z  
} $raxf80A  
else if(nFileLength == -2) &x~&]  
{ 8GRp1'\Hi  
System.err.println("File is not access!"); jC<1bf$K  
} g&z)y  
else E0F8FR'  
{ -)cau-(X  
for(int i=0;i<nStartPos.length;i++) Cs2hi,s  
{ +y%"[6c|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <d2?A}<  
} (~C_zG  
for(int i=0;i<nEndPos.length-1;i++) W6N3u7mrb  
{ '. Ww*N  
nEndPos = nStartPos[i+1]; +w'"N  
} x#wkODLqi  
nEndPos[nEndPos.length-1] = nFileLength; 5U%J,W  
} E cS+/  
} ;3\oU$'  
E;$;g#ksf  
+sN'Y/-  
//启动子线程 aT9+] Ig  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; YIP /N  
for(int i=0;i<nStartPos.length;i++) ^]x%z*6  
{ , `4chD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i}fAjS:W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), t r)[6o#  
nStartPos,nEndPos,i); ,tt .oF|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5m.{ayE  
fileSplitterFetch.start(); _G$SA-W(  
} pN\YAc*@:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hLs<g!*O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Y|'0bujr  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9\yGv  
nEndPos = " + nFileLength); "c0I2wq  
// fileSplitterFetch[nPos.length-1].start(); X@ zw;Se  
yH\3*#+  
B =EI&+F+  
//等待子线程结束 |rjHH<  
//int count = 0; rV yw1D  
//是否结束while循环 _J|TCm  
boolean breakWhile = false;  [#+yL  
QNH-b9u>8  
nRP|Qt7>  
while(!bStop) l|, Hj  
{ o'oA.'ul  
write_nPos(); (8Q0?SZN  
Utility.sleep(500); % oPt],>  
breakWhile = true; {P'_s ]B)  
d|P,e;m-  
W^a-K  
for(int i=0;i<nStartPos.length;i++) K-_XdJ\  
{ 74[wZDW|(  
if(!fileSplitterFetch.bDownOver) \a_75^2  
{ + ESEAi91  
breakWhile = false; *3uBS2Ld  
break; >i6sJ)2?>  
} 4AIo,{(  
} \wJ2>Q  
if(breakWhile) :\!D 6\o6  
break; fwkklg^  
=:w]EpH"  
`Z#0kpXk_  
//count++; #9( 0.!v  
//if(count>4) mJ_ 5Vt=  
// siteStop(); t zTnFV  
} 2HNAB4 E  
~wtK(U  
cEdf&*_-'I  
System.err.println("文件下载结束!"); Fjs:rZ#{  
} KF4D)NM|  
catch(Exception e){e.printStackTrace ();} Z<yLu'48)A  
} vz$_Fgsc.  
xj ?#]GR  
p#\JKx  
//获得文件长度 0[# zn  
public long getFileSize() _#dBcEH[  
{ J]!&E~Y  
int nFileLength = -1; VW$a(G_h  
try{ ?Iin/<y  
URL url = new URL(siteInfoBean.getSSiteURL()); 9wTN *y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jkQ%b.a  
httpConnection.setRequestProperty("User-Agent","NetFox"); {h}0"5  
z[cs/x  
c\Z.V*o  
int responseCode=httpConnection.getResponseCode(); ^vj}  
if(responseCode>=400) s~z~9#G(6  
{ hf JeVT-/v  
processErrorCode(responseCode); W0I)< S  
return -2; //-2 represent access is error h 7P<3m}  
} f-!P[6bY  
'^{:HR#i  
+55+%oGl  
String sHeader; f@j)t%mh  
_.{I1*6Y2  
qk{+Y  
for(int i=1;;i++) @W1F4HYds  
{ m8T< x>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n9%&HDl4  
//Utility.log(in.readLine()); 9n#lDL O  
sHeader=httpConnection.getHeaderFieldKey(i); *QGyF`Go{  
if(sHeader!=null) HM]mOmL90N  
{ V JJ6q  
if(sHeader.equals("Content-Length")) {f(RYj  
{ m]?C @ina  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .eHOG]H  
break; V0/PjD,jP  
} T2dv!}7p  
} QVR8b3T@  
else L25v7U  
break; {@&%Bq*&  
} 4lF(..Ix  
} rqi/nW  
catch(IOException e){e.printStackTrace ();} BN~gk~t_  
catch(Exception e){e.printStackTrace ();} S8dX8,qg  
d7]~t|  
}0oVIr  
Utility.log(nFileLength); tW -f_0a.  
iD${7 _  
X{u\|e{  
return nFileLength; Pm/Rc  
} g}OZ!mKd  
PC<[ $~  
s L=}d[  
//保存下载信息(文件指针位置) 6Bf aB:  
private void write_nPos() 1PUeU+  
{ i",7<01  
try{ 1=Z, #r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); rizWaw5E!8  
output.writeInt(nStartPos.length); .Cz9?]jyI  
for(int i=0;i<nStartPos.length;i++) _+6aD|7x  
{ J3z:U&%=  
// output.writeLong(nPos); Fl}{"eCF8  
output.writeLong(fileSplitterFetch.nStartPos); <}Hs@`jS  
output.writeLong(fileSplitterFetch.nEndPos); n)uck5  
} i}gsxq%  
output.close(); KK';ho,W  
} #8/pYQ;  
catch(IOException e){e.printStackTrace ();} V^%P}RFMc  
catch(Exception e){e.printStackTrace ();} 7t3ps  
} DLH|y%"  
*hIjVKTu79  
V%Ww;Ca]I  
//读取保存的下载信息(文件指针位置) :[J'B4>9  
private void read_nPos() ku5vaP(  
{ sKwUY{u\M  
try{ .z, ot|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {fI"p;|  
int nCount = input.readInt(); H(gETRh  
nStartPos = new long[nCount]; 045_0+r"@  
nEndPos = new long[nCount]; `LOW)|6r`  
for(int i=0;i<nStartPos.length;i++) LEC=@) B  
{ I&9Itn p$  
nStartPos = input.readLong(); _J X>#h  
nEndPos = input.readLong(); `{1~]?-&  
} @q"HZO[  
input.close(); 8'* /|)Hn  
} 8P* d  
catch(IOException e){e.printStackTrace ();} gVI{eoJ  
catch(Exception e){e.printStackTrace ();} n09P!],Xa  
} *TgD{>s  
[ 0z-X7=e  
)?;+<,  
private void processErrorCode(int nErrorCode) [?55vYt  
{ )m$MC25  
System.err.println("Error Code : " + nErrorCode); ;-^8lWt  
} ~7>D>!!  
O_ d[{e=5`  
g `(3r  
//停止文件下载 c<ORmg6  
public void siteStop() FWW*f _L  
{ d]K$0HY  
bStop = true; )l H`a  
for(int i=0;i<nStartPos.length;i++) ?UV|m  
fileSplitterFetch.splitterStop(); $'n?V=4  
]P >c{  
0{(5J,/BF  
} qH(HcsgD  
} dC>(UDC  
//负责部分文件的抓取 @xeJ$ rlu  
**FileSplitterFetch.java tz9"#=}0  
*/ J^-a@' `+  
package NetFox; 4hx4/5[^  
DJb9] ,=a  
# TZ`   
import java.io.*; o]DYS,v  
import java.net.*; L:\>)6]Ls  
CrB4%W:{  
xEg@Y"NQ  
public class FileSplitterFetch extends Thread { NwN3T]W  
.q<5OE(f  
SQJ +C%   
String sURL; //File URL Mq='|0,  
long nStartPos; //File Snippet Start Position i`w)dS  
long nEndPos; //File Snippet End Position Xc$Zkfmms  
int nThreadID; //Thread's ID w!jY(WK U  
boolean bDownOver = false; //Downing is over PlR$s  
boolean bStop = false; //Stop identical EE-wi@  
FileAccessI fileAccessI = null; //File Access interface phR:=Ox|1  
,uPN\`.u8  
>P ~j@Lv  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q[(1zG%NbA  
{ 05Q4$P  
this.sURL = sURL; |W*5<2Q9  
this.nStartPos = nStart;  I)MRAo  
this.nEndPos = nEnd; {f\{{JJ]  
nThreadID = id; ~KczP1p  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3e9UDN2  
} ]app9  
#nq_R  
" u)e,gu  
public void run() $Lz!04  
{ =fJ  /6  
while(nStartPos < nEndPos && !bStop) &$ fyY:<\  
{ pV O{7I  
Y+h ?HS  
&F8*>F^7  
try{ v]#[bqB.b  
URL url = new URL(sURL); 2({|LQqk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n~ZZX={a  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]xGpN ]u  
String sProperty = "bytes="+nStartPos+"-";  niyI$OC  
httpConnection.setRequestProperty("RANGE",sProperty); /!%?I#K{Wq  
Utility.log(sProperty); tn;{r  
X\kWJQ:  
2BiFP||  
InputStream input = httpConnection.getInputStream(); ZiPz~G0[^  
//logResponseHead(httpConnection); \Vpv78QF;  
dL~^C I  
r>gf&/Pl  
byte[] b = new byte[1024]; \Hw*q|  
int nRead; juI)Do2_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0mNL!"  
{ $/ g<h  
nStartPos += fileAccessI.write(b,0,nRead); `FwE^_9d  
//if(nThreadID == 1) AH?[K,3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KquuM ]5S  
} 3WpQzuHPT  
5uV_Pkb?8  
:!^NjO  
Utility.log("Thread " + nThreadID + " is over!"); Wt.['`c<  
bDownOver = true; 97/ 4J  
//nPos = fileAccessI.write (b,0,nRead); EQQ@nW{;  
} ..5. ":  
catch(Exception e){e.printStackTrace ();} RXw1HRR$V  
} b~2LD3"3  
} 6z]y =J  
_sn<"B%>  
jO9! :L>b`  
//打印回应的头信息 bokr,I3  
public void logResponseHead(HttpURLConnection con) _9dW+  
{ NKc<nYdK?  
for(int i=1;;i++) (*kKfg4Wj  
{ nd$92H  
String header=con.getHeaderFieldKey(i); Ta$55K0  
if(header!=null)  tN.$4+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m6'9Id-:L  
Utility.log(header+" : "+con.getHeaderField(header)); _2{2Xb  
else \Rs9B .  
break; SYh>FF"  
} @urZ  
} /N#=Tol  
hAt4+O&P  
;GKL[ tI"  
public void splitterStop() `q`ah_  
{ zG{jRth  
bStop = true; i'.D=o  
} vz)R84   
{Us^ 4Xe  
YkE_7r(1  
} 7rYBFSp  
=oM#]M'G+(  
'h^Ya?g  
/* L)4~:f)B  
**FileAccess.java @t0T+T3  
*//文件访问(定位,写) l-Ha*>gX[j  
package NetFox; UFLx'VX d  
import java.io.*; `PUxR8y  
s}-j.jzB{  
,N;2"$+E  
public class FileAccessI implements Serializable{ dkY JO!  
j5og}P q:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 JH u>\{8V  
RandomAccessFile oSavedFile; _s<s14+od  
long nPos; HAo=t  
'nq~1 >i  
=qbN?a/?2  
public FileAccessI() throws IOException `%^w-'  
{ ^>>9?  
this("",0); ,F*HZBNFZ  
} A,xPA  
5%4yUd#b  
ng~LCffpY  
public FileAccessI(String sName,long nPos) throws IOException Z"qJil}  
{ ^Bo'87!.  
oSavedFile = new RandomAccessFile(sName,"rw"); +FAxqCkA  
this.nPos = nPos; C<(qk_  
oSavedFile.seek(nPos); zbr^ulr  
} <6s@eare8  
@2mWNYHR*>  
rA^=;?7Q  
public synchronized int write(byte[] b,int nStart,int nLen) f$9|qfW'$  
{ +>%51#2.Q  
int n = -1; 8'_MCx(  
try{ +v'2s@e` #  
oSavedFile.write(b,nStart,nLen); =v 'Aub  
n = nLen; h_\( $"  
} Bo14t*(  
catch(IOException e) q`.=/O'  
{ Lb?q5_  
e.printStackTrace (); $06('Hg&  
} 'U*#7 1S  
dh.{lvlX|  
j l]3B  
return n; /I1n${{5  
} 'rS\9T   
zb4{nzX=  
mXS"nd30bD  
} R'6(eA[K  
Ihr[44#  
|z"$^|@d?  
/* .{ZJywE<  
**SiteInfoBean.java J7C?Z  
*/ HG< z,gE 2  
package NetFox; -T i<H9OV  
C9!FnvH  
`p1B58deC  
public class SiteInfoBean { l'M/et{:  
Q+wO\TtE  
Q'!'+;&%  
private String sSiteURL; //Site's URL sDR Av%w  
private String sFilePath; //Saved File's Path YJ-<t6  
private String sFileName; //Saved File's Name + !" Y C  
private int nSplitter; //Count of Splited Downloading File .C5<uW5-R  
n~BQq-1  
SIKaDIZ  
public SiteInfoBean() w{lj'3z I  
{//nSplitter的缺省值为5 :-lq Yd5^  
//default value of nSplitter is 5 DU)q]'[u  
this("","","",5); tQYV4h\Qj  
} eK5~gnv,  
2{Dnfl'k  
zUDXkG*Lv  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Qds:*]vGS  
{ C[hNngb7R  
sSiteURL= sURL; Ayv:Pv@  
sFilePath = sPath; V6_5v+n  
sFileName = sName; );y ZyWDV  
this.nSplitter = nSpiltter; ,3iD/8_  
0v9i43[S|J  
n/ :#:  
} =hd0Ui>x  
tZm`(2S  
+5I'? _{V  
public String getSSiteURL() 6v]`s  
{ 4}t&yu<P>  
return sSiteURL; 1Y;.fZE  
} isy[RAP<  
=R 4]Kf  
Y:#B0FD,gC  
public void setSSiteURL(String value) [u=yl0f  
{ gdoaXw;Sy  
sSiteURL = value; 3Nwix_&S  
} yB/F6/B~  
;($xAAR  
9z{g3m70@  
public String getSFilePath() tS5J{j>T  
{ #G?#ot2o  
return sFilePath; f*88k='\W  
} y29G#Y4J  
@8w5Oudvx  
vJct)i  
public void setSFilePath(String value) v@ qDR|?^  
{ 1zG6^U  
sFilePath = value; ?(Tin80=r  
} W1Fhx`  
y`5 ?  
JUj.:n2e  
public String getSFileName() (CH6Q]Wi_!  
{ yiXb<g+B  
return sFileName; aIQC[ry  
} ^c9_F9N  
6[RTL2&W  
1JdMw$H  
public void setSFileName(String value) ~Ym*QSD  
{ ]bmf}&  
sFileName = value; f%1\1_^g  
} 7fzH(H  
M #0v# {o  
PX0N7L  
public int getNSplitter() 1:- M<=J?f  
{ J7oj@Or9  
return nSplitter; hR:i!  
} ) ?B-en\  
" W{rS4L  
4 #KC\C  
public void setNSplitter(int nCount) w S?Kc^2O  
{ F Pjc;zNA  
nSplitter = nCount; (fr=[m$`  
} -^t.eZ*|  
} d2US~.;>l  
7QZy d-  
xXI WEZA  
/* 5 8L@:>"  
**Utility.java ]TUoXU2<x  
*/ /X0<2&v  
package NetFox; l x0BKD?n  
<^Y #q  
tn _\E/Q  
public class Utility { `s\[X-j]  
kB5y}v.3 S  
7h!nt=8Y  
public Utility() EbVC4uY  
{ nGK=Nf.5  
$7xfLS8Vo  
uh#E^~5S  
} a #s Nd  
<;>k[P'  
//线程睡眠 $Jn.rX0}$  
public static void sleep(int nSecond)  xiQc\k$  
{ "?<`]WG\  
try{ /#"9!8%V  
Thread.sleep(nSecond); yLnTIE3)  
} bO6cv{>x  
catch(Exception e) qJK9C `T%  
{ e.(d?/!F_  
e.printStackTrace (); ygm6(+  
} |a /cw"  
} %iYro8g!,  
)@y'$)5s  
//日志 &gC)%*I 4  
public static void log(String sMsg) @m:' L7+  
{ P@n rcgM.  
System.err.println(sMsg); t4~?m{  
} 2v4&'C  
5 ^l-3s?M  
2\O!vp>|-  
public static void log(int sMsg) VC Ay~,  
{ dvY3=~'  
System.err.println(sMsg); sT<h+[2d  
} |pU>^  
} p&`I#6{  
ZD$I-33W  
B tJF1#f  
/* l +`CgYo  
**TestMethod.java [{T/2IGq  
*/ %4#ChlXB  
package NetFox; ntL%&wY  
Q'ib7R;V,  
:'fK`G 6  
public class TestMethod { +:c}LCI9<  
,g|ht%"  
U}=H1f,  
public TestMethod() M3GFKWQI,`  
{ ///xx/weblogic60b2_win.exe 6OQ\f,h@  
try{ (f#{<^gd  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )^ )|b5,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;D4 bxz0ou  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (V/! 0Lj  
fileFetch.start(); I3l1 _  
} Hb^ovc0   
catch(Exception e){e.printStackTrace ();} mryT%zSlM  
abEdZ)$  
z!~{3M  
} H66~!J0;a  
?ia O6HD  
N a.e1A&?j  
public static void main(String[] args) uIJ zz4  
{ &mA{_|>  
new TestMethod(); z^%`sUgP  
} REk^pZ3B  
} !+Sd%2o  
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