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http断点续传简单实现(java)

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/* ww%4MHPp8  
**SiteFileFetch.java eISHV.QV  
*/ U}=H1f,  
package NetFox; KO}TCa  
import java.io.*; <3=k  
import java.net.*; 1.~^QH\p?3  
,s@S`KS0  
 Bv%dy[I  
public class SiteFileFetch extends Thread { NX]6RZr-  
qe0ZM-C_  
9~iDL|0'~  
SiteInfoBean siteInfoBean = null; //文件信息Bean Zyz)`>cB  
long[] nStartPos; //开始位置 {w99~?  
long[] nEndPos; //结束位置 RcI0n"Gi_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 O7,:-5h0  
long nFileLength; //文件长度 j{/wG::  
boolean bFirst = true; //是否第一次取文件 [t5 Dd  
boolean bStop = false; //停止标志 ]tbl1=|  
File tmpFile; //文件下载的临时信息 2Myz[)<P_  
DataOutputStream output; //输出到文件的输出流 J+hifO  
X%B2xQM 5  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) PC!X<C8*  
public SiteFileFetch(SiteInfoBean bean) throws IOException 'sI @e s  
{ C\ cZ  
siteInfoBean = bean; #q?:Act  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); VOp+6ho<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); uv7tbI"r  
if(tmpFile.exists ()) 2-"`%rE  
{ p!K]c D  
bFirst = false; S?~/ V]  
read_nPos(); <bBgevL+_K  
} @Z9>E+udQ  
else ?T[K{t;~jo  
{ ` B+Pl6l)F  
nStartPos = new long[bean.getNSplitter()]; `{S4_'  
nEndPos = new long[bean.getNSplitter()]; ob(~4H-  
} 3HX-lg`0  
45Q#6Bt E  
I{u+=0^Y  
};8PPR)\y  
} DEKO] i  
~NO'8 Mr  
sRGIHT#  
public void run() ]LSlo593  
{ ]i'gU(+;`  
//获得文件长度 Hb9r.;r<EW  
//分割文件 RsP^T:M}$  
//实例FileSplitterFetch &-`a`  
//启动FileSplitterFetch线程 DGx<Nys@B  
//等待子线程返回 6 Zv~c(   
try{ t3aDDu  
if(bFirst) ot,e?lF  
{ aw'o=/a8  
nFileLength = getFileSize(); |f"1I4K g  
if(nFileLength == -1) ~`Rooh3m  
{ Cv1CRmqq%  
System.err.println("File Length is not known!"); ]=0$-ImQ@x  
} !X/O1PM|  
else if(nFileLength == -2) @>hXh +!2h  
{ }kb6;4>c  
System.err.println("File is not access!"); 7 [?]DyOf  
} Gv }~  
else o_%gFV[q  
{ w<=-n ;2  
for(int i=0;i<nStartPos.length;i++) $T}Dn[.  
{ EN2/3~syO-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]AdL   
} 6SmawPPP  
for(int i=0;i<nEndPos.length-1;i++) -VRKQNT  
{ }q[IhjD%  
nEndPos = nStartPos[i+1]; o^& nkR  
} !5h@uar  
nEndPos[nEndPos.length-1] = nFileLength; \"hP*DJ"  
} ,zH\&D$>u  
} $iAd)2LT  
GxcW^{;  
7W\aX*]  
//启动子线程 &Kc'g H  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \jThbCb  
for(int i=0;i<nStartPos.length;i++) Av^<_`L :  
{ Z?tw#n[T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q?TXM1Bp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^G]H9qY- e  
nStartPos,nEndPos,i); $79-)4;z4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9q f=P3  
fileSplitterFetch.start(); CaqMLi%  
} 7`Bwo*Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uNRT@@oCq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9$:+5f,%a  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #sp8 !8|y  
nEndPos = " + nFileLength); "f<+~  
// fileSplitterFetch[nPos.length-1].start(); @jevY81)  
OLM}en_L  
Di8;Tq  
//等待子线程结束 :*{\oqFn~$  
//int count = 0; &C7HG^;W9  
//是否结束while循环 h9L/.>CX  
boolean breakWhile = false; p?zh4:\F+  
1(12`3  
j8"2K^h=  
while(!bStop) d9sqO9Ud8  
{ !2Q>   
write_nPos(); z@n779i  
Utility.sleep(500); bkfk9P  
breakWhile = true; ]w[T_4 l  
[v$NxmRu  
v<U +&D{  
for(int i=0;i<nStartPos.length;i++) '+{dr\nJ  
{ 3?R QPP  
if(!fileSplitterFetch.bDownOver) 'uOzC"_yF  
{ |]9Z#lv+I  
breakWhile = false; %[C-KQH  
break; >ey- j\_v  
} 4C{3>BE  
} K'zG[[P  
if(breakWhile) fCxF3m(O  
break; Z'I0e9Jw  
d(-$ { c  
E[RLBO[*n  
//count++; =wy3h0k^  
//if(count>4) Z*rA~`@K6  
// siteStop(); /Aq):T T  
} NJglONO  
MjHjL~Tg  
[o,S.!W8  
System.err.println("文件下载结束!"); *jF VYg  
} BsX# ~  
catch(Exception e){e.printStackTrace ();} HBFuA.",  
} $ (gR^L  
U@$=0*  
%aszZP  
//获得文件长度 Hf'yRKACj  
public long getFileSize() >xt*(j&}  
{ 9#;UQ.qA  
int nFileLength = -1; K{&b "Ba1  
try{ *G{Zo*2< i  
URL url = new URL(siteInfoBean.getSSiteURL()); O<x53MN^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j;k(AM<  
httpConnection.setRequestProperty("User-Agent","NetFox"); Tcglt>tj"  
^8V cm*  
(1vmtg.O  
int responseCode=httpConnection.getResponseCode(); Qp?n0WXZ  
if(responseCode>=400) q$Ol"K@  
{ pw7_j;}l  
processErrorCode(responseCode); IrRn@15,  
return -2; //-2 represent access is error .F~EQ %  
} "F+Wo&  
S %"7`xl  
Ik#>6  
String sHeader; YJ5;a\QxN  
A*h)p@3t<  
3\,TI`^C  
for(int i=1;;i++) fuH Dif,  
{ iDO~G($C  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (!';  
//Utility.log(in.readLine()); / N@0qQ  
sHeader=httpConnection.getHeaderFieldKey(i); 2#A u6BvX  
if(sHeader!=null) |yI?}zyR  
{ n^/,>7J   
if(sHeader.equals("Content-Length")) F|V co]"S1  
{ 'Ph4(Yg  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); LwUvM  
break; @T1 >%oi  
} |k'I?:'  
} U[S;5xeF.j  
else 2|~& x~  
break; -X4`,0y%{O  
} s=huOjKL]  
} q9Y0Lk  
catch(IOException e){e.printStackTrace ();} 9GZF39w u  
catch(Exception e){e.printStackTrace ();} :;" 3k64  
B>47Ic  
!9o8v0ZI  
Utility.log(nFileLength); &TbnZnv  
#G#gB   
oRu S_X  
return nFileLength; j7-#">YL  
} c_^H;~^rL  
l}AB):<Z  
o7 !@WOeZ3  
//保存下载信息(文件指针位置) dm$:xE":  
private void write_nPos() 72-@!Z0e  
{ V43JY_:  
try{ "<O?KO 3K  
output = new DataOutputStream(new FileOutputStream(tmpFile)); NHc+QMbou(  
output.writeInt(nStartPos.length); 5o~Z>  
for(int i=0;i<nStartPos.length;i++) YgWnPp  
{ P6=|C;[  
// output.writeLong(nPos); fQx 4/4j  
output.writeLong(fileSplitterFetch.nStartPos); |J}~a8o  
output.writeLong(fileSplitterFetch.nEndPos); 9J]LV'f7  
} \+Cp<Hv+  
output.close(); d&'6l"${  
} *gT TI;:  
catch(IOException e){e.printStackTrace ();} \O/=g6w|t}  
catch(Exception e){e.printStackTrace ();} +vbNZqwz  
} A`r&"i OKA  
!E7/:t4  
2dI:],7  
//读取保存的下载信息(文件指针位置) rz.`$b  
private void read_nPos() z(%Zji@!N  
{ zR<jZwo]#  
try{ q{_buTARq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); gVl#pVO`N  
int nCount = input.readInt(); ss2:8up 99  
nStartPos = new long[nCount]; IaF79}^  
nEndPos = new long[nCount]; vMI\$E &  
for(int i=0;i<nStartPos.length;i++) {jq-dL  
{ [wOO)FjT  
nStartPos = input.readLong(); D>1Dao  
nEndPos = input.readLong(); )t.q[O`  
} ?D~uR2+Z  
input.close(); . }1!MK5  
} 4v?S` w:6  
catch(IOException e){e.printStackTrace ();} -FPl",f=r  
catch(Exception e){e.printStackTrace ();} 2Vi[qS^  
} FJ[(dGKeE  
(C:rH  
6RtpB\hq  
private void processErrorCode(int nErrorCode) w5nRgdboy!  
{ [zfGDMG&  
System.err.println("Error Code : " + nErrorCode); C/$IF M<  
} Av[jFk  
F`N*{at  
KG?]MVXA  
//停止文件下载 bC{~/ JP  
public void siteStop() \E30.>%,  
{ Q7s1M&K  
bStop = true; bd9c/>&  
for(int i=0;i<nStartPos.length;i++) R3<+z  
fileSplitterFetch.splitterStop(); aG ,uF  
G@;aqe[dB  
Xgm7>=l  
} )Qc$UI8L  
} Psv!`K  
//负责部分文件的抓取 _Dv^~e1c  
**FileSplitterFetch.java {xr]xcM'b  
*/ E5 dXu5+ye  
package NetFox; Ob6vg^#  
Q9'p2@Z  
L9.#/%I\  
import java.io.*; g,;MV7yE  
import java.net.*; Uwp +w  
O<hHo]jLF  
x<l1s  
public class FileSplitterFetch extends Thread { y{N9.H2  
,y>Na{@Y  
ymzm x$o=  
String sURL; //File URL A_.QHUjpx  
long nStartPos; //File Snippet Start Position { nV zN(  
long nEndPos; //File Snippet End Position aI<~+]  
int nThreadID; //Thread's ID }:%pOL n  
boolean bDownOver = false; //Downing is over 1mX*0>  
boolean bStop = false; //Stop identical =6sXZ"_Tw  
FileAccessI fileAccessI = null; //File Access interface %Z7!9+<  
E;qwoTmul  
@2mP  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ZeeuH"A  
{ (Ka# 6   
this.sURL = sURL; coWBKWF  
this.nStartPos = nStart; Y[!a82MTzn  
this.nEndPos = nEnd; Trrh`@R  
nThreadID = id; 3\{Sf /#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _a&|,ajy >  
} ZYA(Bg^  
,:`6x[ +  
"" U_|JH-  
public void run() _#C}hwOR>X  
{ )hug<D *h  
while(nStartPos < nEndPos && !bStop) HhL%iy1  
{ K>[H@|k\k  
qC )VT3  
`y}d)"!  
try{ />C~a]}  
URL url = new URL(sURL); 9QMn%8=j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X2cR+Ha0  
httpConnection.setRequestProperty("User-Agent","NetFox"); R~~rqvLm  
String sProperty = "bytes="+nStartPos+"-"; `xUPML-  
httpConnection.setRequestProperty("RANGE",sProperty); >|?T|  
Utility.log(sProperty); rHlF& ET  
!qlGt)G3  
(5~C _Y  
InputStream input = httpConnection.getInputStream(); Z+"&{g  
//logResponseHead(httpConnection); tWn m{mF  
F"xO0t  
B5:g{,C  
byte[] b = new byte[1024]; prtxE&-  
int nRead; -`OR6jd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) KIo}Gd&  
{ h '[vB^  
nStartPos += fileAccessI.write(b,0,nRead); t\i1VXtO  
//if(nThreadID == 1) Zjg\jo  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u4@e=vW I  
} "!tw ,Gp  
Nb~dw;t  
K//T}-Uub  
Utility.log("Thread " + nThreadID + " is over!"); #OWs3$9  
bDownOver = true; hX m} d\  
//nPos = fileAccessI.write (b,0,nRead); 6;cY!  
} L\NZDkd  
catch(Exception e){e.printStackTrace ();} ,g_onfY  
} R*Z]  
} AwU c{h l<  
OZD!#YI  
H@E" )@92  
//打印回应的头信息 E[.tQ|C  
public void logResponseHead(HttpURLConnection con) W@,p9=425  
{ hF"g 91P  
for(int i=1;;i++) O}_a3>1DY  
{ ttaQlEa=Z  
String header=con.getHeaderFieldKey(i); {|Ki^8h/p  
if(header!=null) cEc,eq|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >}b6J7_  
Utility.log(header+" : "+con.getHeaderField(header)); zN+* R;Ds  
else #we>75l{+R  
break; pXh~#o6 V  
} s;2/Nc   
} x$GsDV  
sD8 m<   
VtO;UN  
public void splitterStop() vX0"S  
{ kq~[k.  
bStop = true; Y#&0x_Z  
} \c~{o+UD-  
u:$x6/t  
LkGf|yd_  
} 6lmiMU&V  
5 n+ e  
4su_;+]  
/* *Z`XG_s5  
**FileAccess.java /.)[9bQ<  
*//文件访问(定位,写)  (X(1kj3  
package NetFox; H5rPq_R  
import java.io.*; Q_aqX(ig  
{(Og/[  
;wXY3|@  
public class FileAccessI implements Serializable{ FU\/JF.j  
oWDSK^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 N pXgyD  
RandomAccessFile oSavedFile; 5BHOHw D{  
long nPos; ~J1;tZS  
iog # ,  
>H}jR[H'  
public FileAccessI() throws IOException Jf?S9r5Q  
{ Wk`bb!P_  
this("",0); wKk 3)@il  
} x^)g'16`  
Y  .  
4r1<,{gCS  
public FileAccessI(String sName,long nPos) throws IOException ]D LZ&5pv  
{ K lli$40  
oSavedFile = new RandomAccessFile(sName,"rw"); K[uY+!'1  
this.nPos = nPos; JFRpsv  
oSavedFile.seek(nPos); X<~k =qwA  
} V)0[`zJ  
'u(=eJ@1  
Cs:+93w  
public synchronized int write(byte[] b,int nStart,int nLen) D[89*@v  
{ 1mHwYT+  
int n = -1; -(\1r2 Y  
try{ x0\e<x9s  
oSavedFile.write(b,nStart,nLen); g.I(WJX0  
n = nLen; qr)v'aC3  
} EkJVFHfh  
catch(IOException e) Aq V09 $  
{ =oE_.ux\  
e.printStackTrace (); %cH8;5U40  
} & u$(NbK  
x37/cu  
J| SwQE~  
return n; ud0QZ X  
} dqqnCXYuW  
WD15pq l  
6xH;: B)d  
} >=if8t!  
N'I(P9@  
JY{X,?s  
/* }@Xh xZu  
**SiteInfoBean.java tNK^z7Dm  
*/ `6&`wKz  
package NetFox; t]s94 R q  
Y!SE;N&  
!*&4< _  
public class SiteInfoBean { i<%m Iq1L  
B!eK!B  
B@ -|b  
private String sSiteURL; //Site's URL 9Ei5z6Vk/+  
private String sFilePath; //Saved File's Path N83!C=X'  
private String sFileName; //Saved File's Name xEjx]w/&  
private int nSplitter; //Count of Splited Downloading File 3 m6$YWO  
mge#YV::  
& =G)NeT_  
public SiteInfoBean() 6N"m?g*Z d  
{//nSplitter的缺省值为5 F8;mYuA  
//default value of nSplitter is 5 Zr=ib  
this("","","",5); k@S)j<  
} Gb;99mE  
C>^,*7dS  
".gNeY6)x  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) rn;<HT  
{ z<!O!wX_aI  
sSiteURL= sURL; ]DO&x+Rb  
sFilePath = sPath; vd`O aM}#U  
sFileName = sName; 42&v % ;R  
this.nSplitter = nSpiltter; *ot> WVB  
`?l3Ct*  
"# !D|[h0  
} 2`EVdl7B]  
;`DD}j`  
qe<Hfp/p  
public String getSSiteURL() OZf6/10O/  
{ e!GZSk   
return sSiteURL; D93gH1z  
} msiu8E  
3f"C!l]Xu  
V43TO  
public void setSSiteURL(String value) eIH$"f;L  
{ dN< , %}R  
sSiteURL = value; P;73Hr[E#  
} \Wr,<Y  
Nar>FR7ut  
cMaOM}mS  
public String getSFilePath() TN\|fzj  
{ \w%@?Qik  
return sFilePath; QOH<]~3J  
} A|L'ih/  
9gy(IRGq/  
O(c@PJem  
public void setSFilePath(String value) a7#?h%wf  
{ iG#}`  
sFilePath = value; %Ds+GM-  
} H}/05e  
5wv fF.v  
Y]Vq\]m\  
public String getSFileName() U<^F4*G  
{ \vRd}   
return sFileName;  cG{L jt  
} ?IF)+]  
* ?]~ #  
>P=Q #;v  
public void setSFileName(String value) s2REt$.q  
{ 3TS_-l  
sFileName = value; g<wRN#B  
} <CZgQ\Mt  
_MuZ4tc  
;j9\b9m  
public int getNSplitter() E=$p^s  
{ ) #+^ sAO  
return nSplitter; jQ+sn/ROp  
} ~Lz%.a;o  
Gh\q^?}  
&%mXYj3y5  
public void setNSplitter(int nCount) Pw[g  
{ Ef)yQ  
nSplitter = nCount; U*)m' ,  
} ]uQqn]+I!  
} yN6>VD{F  
&JP-O60  
}H"kU2l  
/* 1P(&J  
**Utility.java g(|{')8?d  
*/ t#i,1aHA  
package NetFox; OLC{iD#  
.@F]Pht  
,|kDsR !  
public class Utility { 4\M.6])_   
cC'x6\a  
?OlV"zK  
public Utility() N!2Rl  
{ DA&?e~L&H  
o*rQP!8,oy  
[*:6oo98'  
} T~_/Vi  
D BE4&  
//线程睡眠 A:l@_*C..  
public static void sleep(int nSecond) 5L,}e<S$  
{ ^ vilgg~  
try{ -Go 7"j  
Thread.sleep(nSecond); ig}A9j?]  
} A][fLlpr  
catch(Exception e) ::FS/Y]Fg  
{ B=8Iu5m  
e.printStackTrace (); 9o*,P,j'}  
} qt%D'  
} l 'DsZ9y@2  
91>fqe  
//日志 _BdE< !r  
public static void log(String sMsg) VA *y|Q6  
{ `K~AhlJUQ  
System.err.println(sMsg); ~vlype3/EF  
} 4lhw3,5  
#jA[9gWI  
om?-WJI  
public static void log(int sMsg) B(xN Gs  
{ `Qr%+OD  
System.err.println(sMsg); NT@;N/I  
} _=CZR7:O  
} b4^`DHRu6  
]BR,M4   
{pM?5"M MJ  
/* E dZ\1'&/9  
**TestMethod.java fd-q3 _f  
*/ 5waKI?4F  
package NetFox; rV08ad  
x#Sqn#  
UfS%71l.$  
public class TestMethod { pPd#N'\*  
a7N!B'y  
e[hcJz!D  
public TestMethod() 6G=j6gK%P  
{ ///xx/weblogic60b2_win.exe g=I8@m  
try{ Kq i4hK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _h}kp\sps  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M Y|w  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {nLjY|*  
fileFetch.start(); U8 nH;}i  
} 7jdb)l\p=  
catch(Exception e){e.printStackTrace ();} 8#vc(04(  
%2v4<icvq  
/Q~i~B 2j-  
} #8)*1?  
_3ZYtmn.  
iX)%Q  
public static void main(String[] args) fkac_X$7  
{ P#AW\d^"B  
new TestMethod(); t.;LnrY  
} thhwN A  
} K5lmVF\$P  
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