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http断点续传简单实现(java)

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/* ]xJ2;{JWsO  
**SiteFileFetch.java _T^@,!&  
*/ 1 RyvPP  
package NetFox; ~\R+p~>  
import java.io.*; !O,`Z`T?  
import java.net.*; %yy|B  
\p izVt  
K?wo AuY  
public class SiteFileFetch extends Thread { r-}C !aF]  
4!+IsT  
B?XqH_=0L  
SiteInfoBean siteInfoBean = null; //文件信息Bean %tz foiJ%P  
long[] nStartPos; //开始位置 m!<uY?,hf  
long[] nEndPos; //结束位置 62OZj%CXN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 d _Y7/_i  
long nFileLength; //文件长度 0o!Egq_  
boolean bFirst = true; //是否第一次取文件 5,V3_p:)VI  
boolean bStop = false; //停止标志 ue6&)7:~  
File tmpFile; //文件下载的临时信息 1`&"U[{  
DataOutputStream output; //输出到文件的输出流 /9u12R*<  
BG20R=p  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) _%aJ/Y0Cy  
public SiteFileFetch(SiteInfoBean bean) throws IOException X pf:I  
{ _E[)_yH'-  
siteInfoBean = bean; yFqB2(Dv  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >]8H@. \  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "M:0lUy  
if(tmpFile.exists ()) ,dk!hm u  
{ &p^8zEs  
bFirst = false; pj'[ H  
read_nPos(); #ruL+- 8!<  
} !.5,RIf  
else [,ns/*f3R  
{ lxD~[e  
nStartPos = new long[bean.getNSplitter()]; f>_' ]eM%  
nEndPos = new long[bean.getNSplitter()]; p#(5 ;  
} \ssqIRk  
_QOZ`st  
S_56!  
-]~vE fq+T  
} NXDuO_#  
PzD ekyl  
},G5!3  
public void run() OAZ5I)D>  
{ &,~Oi(SX5  
//获得文件长度 a{7'qmN1  
//分割文件 R<x~KJ11c  
//实例FileSplitterFetch s:\FlQ0  
//启动FileSplitterFetch线程 OB5`a,5dI  
//等待子线程返回 x\R 8W8M  
try{ S+&Bf ~~D  
if(bFirst) mXXU{IwUe  
{ 5ki<1{aVtZ  
nFileLength = getFileSize(); =5m~rJ< {  
if(nFileLength == -1) +&h<:/ V  
{ #)N}F/Od^  
System.err.println("File Length is not known!"); hV]]%zwR+  
} FpM0%   
else if(nFileLength == -2) ?B~S4:9  
{ =;?afUj  
System.err.println("File is not access!"); &`IC 3O5  
} Pwg?a  
else Ryrvu1 k  
{ B)}.%G*  
for(int i=0;i<nStartPos.length;i++) E2~&GkU.UN  
{ &;]KntxB  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Tweku}D7  
} 2Ub!wee  
for(int i=0;i<nEndPos.length-1;i++) J}'a|a@bk  
{ /I/gbmc)  
nEndPos = nStartPos[i+1]; +=N#6 # 1  
} hY S}PE  
nEndPos[nEndPos.length-1] = nFileLength; S)$iHBx{  
} yTb#V"eR  
} qPG>0 O  
70BLd(?  
$"[5]{'J  
//启动子线程 z t|DHVy  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Yg kd1uI.  
for(int i=0;i<nStartPos.length;i++) |)}&: xA%  
{ +zf[Im%E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;*}tbh3;.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Z&W*@(dX  
nStartPos,nEndPos,i); L.tW]43K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f5ttQ&@FF  
fileSplitterFetch.start(); 8.m9 =+)8  
} Yfd0Np~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |%l&H/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); v%$c_'d  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", C!z7sOu  
nEndPos = " + nFileLength); {GP#/5$=  
// fileSplitterFetch[nPos.length-1].start(); ^ 9`O ^  
gql^Inx<  
&=S<StH  
//等待子线程结束 sRkPXzK  
//int count = 0; ; xx u,  
//是否结束while循环 %;MM+xVVX  
boolean breakWhile = false; f~?4  
w1J%%//(h  
nc/F@HCB  
while(!bStop) fDD^?/^  
{ (29BS(|!  
write_nPos(); VSLi{=#  
Utility.sleep(500); fx3oA}  
breakWhile = true; I:Q3r"1  
{&,MkWgG  
\;bDDTM  
for(int i=0;i<nStartPos.length;i++) G'IRqO *]  
{ e61e|hoX\  
if(!fileSplitterFetch.bDownOver) 6s(.u l  
{ jWNF3\  
breakWhile = false; P?/Mrz   
break; l:- <CbG  
} GX0S9s  
} "l[ c/q[  
if(breakWhile) `*-rz<G  
break; >1S39n5z.  
E@[ZwTnJ  
o/4U`U)Q0v  
//count++; ag{cm'.  
//if(count>4) 26B+qXEt  
// siteStop(); #Pr w2u  
} teX)!N [  
fq4[/%6,O  
B:rzM:BQ  
System.err.println("文件下载结束!"); JrNqS[c/  
} 9:JQ*O$  
catch(Exception e){e.printStackTrace ();} d<_#Q7]I4  
} JDP/vNq  
Vqp 3'=No  
G7SmlFn?  
//获得文件长度 Mem1X rBH  
public long getFileSize() Y>Ju$i  
{ B2T=O%  
int nFileLength = -1; =.(~`ici~  
try{ sg%Ptp  
URL url = new URL(siteInfoBean.getSSiteURL()); ^E]y >Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yt[*4gF4  
httpConnection.setRequestProperty("User-Agent","NetFox"); )SzgMbF6  
+nz 0ZQ9 a  
-=4{X R3  
int responseCode=httpConnection.getResponseCode(); "1z#6vw5a  
if(responseCode>=400) [yx8?5  
{ v ocWV/  
processErrorCode(responseCode); s6(bTO.  
return -2; //-2 represent access is error &`I7aP|  
} wu~?P`  
Btyp=wfN[  
-jk-ve  
String sHeader; e N^6gub  
XOT|:  
Z3O_K  
for(int i=1;;i++) K;lxPM]  
{ |31/*J!@z*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); l]~mB~  
//Utility.log(in.readLine()); %`\=qSf*  
sHeader=httpConnection.getHeaderFieldKey(i); >)6k)$x%%  
if(sHeader!=null) N7UGgn=  
{ ]/[$3rPwZ  
if(sHeader.equals("Content-Length")) }9~U5UXWU  
{ "5@\"L  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); SQ-CdpT<  
break; e'T|5I0K  
} aSt:G*a"  
} C`["4  
else q{uv?{I  
break; o?/fObV@(  
} /|p6NK;8L  
} S!8q>d,%L  
catch(IOException e){e.printStackTrace ();} s[Whg!2~  
catch(Exception e){e.printStackTrace ();} z 8<"  
-+fW/Uo  
~n;U5hcB  
Utility.log(nFileLength); JQDS3v=1$  
Y*0j/91  
n8Rsle`a  
return nFileLength; F4$9r^21r  
} @*=eqO  
k-I U}|Xz  
qo7jrY5G  
//保存下载信息(文件指针位置) h3j`X'  
private void write_nPos() <Y)Aez  
{ 0?*":o30  
try{ ~(}n d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); jqQGn"!  
output.writeInt(nStartPos.length); ?*:BgaR_  
for(int i=0;i<nStartPos.length;i++) 6+/BYN!&4  
{ {w mP  
// output.writeLong(nPos); `<(o;*&Gd  
output.writeLong(fileSplitterFetch.nStartPos); h@@q:I=  
output.writeLong(fileSplitterFetch.nEndPos); DHVfb(H5e  
} juB/?'$~  
output.close(); FL[w\&fp  
} R= .UbY  
catch(IOException e){e.printStackTrace ();} KqvM5$3  
catch(Exception e){e.printStackTrace ();} 8TCbEPS@Q  
} |?\2F   
$k^& X `  
\L"0Pmt[  
//读取保存的下载信息(文件指针位置) En ]"^*  
private void read_nPos() Erm]uI9`  
{ %Mf3OtPiJW  
try{ G \|P3j  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ] uXmug  
int nCount = input.readInt(); tS[%C)  
nStartPos = new long[nCount]; 9s#*~[E*  
nEndPos = new long[nCount]; D<lVWP  
for(int i=0;i<nStartPos.length;i++) w_*$w Vl  
{ )JOo|pr-K  
nStartPos = input.readLong(); EO\- J-nM  
nEndPos = input.readLong(); gW^0A)5  
} U]"6KS   
input.close(); {4r }jH  
} 9PG3cCr?  
catch(IOException e){e.printStackTrace ();} nQ;M@k&9eV  
catch(Exception e){e.printStackTrace ();} 7W=s.Gy7G\  
} U /jCM?~  
6OZ n7:)Y  
(S8hr,%n  
private void processErrorCode(int nErrorCode) 8r.3t\o)X  
{ K QCF "  
System.err.println("Error Code : " + nErrorCode); RpzW-  
} BP=<TRp .  
t]+h.  
sM@1Qyv&0  
//停止文件下载 =W"9a\m  
public void siteStop() 7o9[cq w  
{ HJ!P]X_J1  
bStop = true; jBJ|%K M  
for(int i=0;i<nStartPos.length;i++) 8>'vzc/* >  
fileSplitterFetch.splitterStop(); k#x"'yZ  
Mc 6v  
jR"ACup(  
} ,p6o "-  
} 90">l^HX=  
//负责部分文件的抓取 G],W{<Pe  
**FileSplitterFetch.java Q$x 3uH\@  
*/ 43Ua@KNi  
package NetFox; ADB,gap  
a>eg H og  
ZX0!BS  
import java.io.*; ~y1k2n  
import java.net.*; R!2E`^{Wl  
6o~CX  
{$'oKJy*  
public class FileSplitterFetch extends Thread { -qpe;=g&f  
,Ofou8C6  
+,J!xy+~,  
String sURL; //File URL 4x_# 1 -  
long nStartPos; //File Snippet Start Position =/bC0bb{i  
long nEndPos; //File Snippet End Position URMxCL^"  
int nThreadID; //Thread's ID Q;=3vUN  
boolean bDownOver = false; //Downing is over RIq\IQ_|  
boolean bStop = false; //Stop identical .|GnTC q  
FileAccessI fileAccessI = null; //File Access interface Z"E2ZSa0  
.>^U mM  
=HHb ]JE  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qwYq9A$+  
{ g]U! ]  
this.sURL = sURL; | ?ma?  
this.nStartPos = nStart; }PzHtA,V  
this.nEndPos = nEnd; I G B)  
nThreadID = id; #<yKG\X?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Yw,LEXLY  
} ]9~6lx3/  
e.]k4K  
2Y%E.){  
public void run() +6f[<^K#  
{ ?]0bR]}y  
while(nStartPos < nEndPos && !bStop) ig4mj47wJ  
{ /y- 8dgv0a  
@O)1Hnm  
pR3K~bx^  
try{ nh>lDfJV<  
URL url = new URL(sURL); Z)G@ahO Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }Pj;9ivz  
httpConnection.setRequestProperty("User-Agent","NetFox"); M$2lK^2L  
String sProperty = "bytes="+nStartPos+"-"; h F *c  
httpConnection.setRequestProperty("RANGE",sProperty); n hGh5,  
Utility.log(sProperty); {r1}ACw{  
#LfoG?k1K  
z&Lcl{<MA  
InputStream input = httpConnection.getInputStream(); DTC OhUIV  
//logResponseHead(httpConnection); k4YW;6<C+  
vp`s< ;CA  
8Oo16LPD  
byte[] b = new byte[1024]; nfS.0\z  
int nRead; a<&GsDw  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {GS$7n  
{ P yN{  
nStartPos += fileAccessI.write(b,0,nRead); 6G<gA>V  
//if(nThreadID == 1) 1IWP~G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {'[S.r`  
} nmUMg  
qp2&Z8S\D  
~A-D>.ZH  
Utility.log("Thread " + nThreadID + " is over!"); F+?g0w['  
bDownOver = true; \Wf1b8FW  
//nPos = fileAccessI.write (b,0,nRead); 3/4r\%1b+  
} ]McDN[h:  
catch(Exception e){e.printStackTrace ();} 3ULn ]jA  
} 7/6%92T/B  
} wU/BRz8I  
td(4Fw||1y  
#\gx.2W7  
//打印回应的头信息 dR >hb*k J  
public void logResponseHead(HttpURLConnection con) H]Vo XJ\*  
{ @JpkG%eK  
for(int i=1;;i++) S/xCX!  
{ I.u[9CI7HU  
String header=con.getHeaderFieldKey(i); 3V@!}@y,F6  
if(header!=null) /@+[D{_Fw  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); aui3Mq#f  
Utility.log(header+" : "+con.getHeaderField(header)); #iP5@:!Wm~  
else 9Vtn62+  
break; c_FnJ_++f  
} ]?(_}""1  
} lH%-#2]  
-*~~ 00w  
z*G(AcS)  
public void splitterStop() s?_H<u  
{ u]s}@(+.  
bStop = true; 6G]hs gro  
} ;@V1*7y  
 R]"3^k*  
dn:/8~B"X  
} {V5eHn9/Q'  
i[m-&   
do=s=&T  
/* SX@zDuM  
**FileAccess.java F]6$4o[  
*//文件访问(定位,写) )9z3T>QW  
package NetFox; .0iHI3i^  
import java.io.*; |ZJ<N\\h-  
l[M?"<Ot;  
=SLCG.  
public class FileAccessI implements Serializable{ w}r~Wk^dLI  
f/{*v4!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 QT7PCHP  
RandomAccessFile oSavedFile; ioJr2wq6  
long nPos; .fD%*-  
]]8^j='P'  
<^fvTb&*  
public FileAccessI() throws IOException iBaz1pDc  
{ ZCz#B2Sf8  
this("",0); eGQ -Ht,N  
} _68{ {.  
zHk7!|%Y  
QBL|n+  
public FileAccessI(String sName,long nPos) throws IOException L1YiXJ,T,  
{ SRek:S,  
oSavedFile = new RandomAccessFile(sName,"rw"); Pj{Y  
this.nPos = nPos; B8.uzX'p  
oSavedFile.seek(nPos); V3q[#.o  
} XG}9) fT  
%#iu  
u @#fOu  
public synchronized int write(byte[] b,int nStart,int nLen) (.N!(;G  
{ ;T*o RS  
int n = -1; x f<wM]&  
try{ Y[Eq;a132  
oSavedFile.write(b,nStart,nLen); ?OF9{$m3?  
n = nLen; Qkb=KS%z  
} DZqY=Sze  
catch(IOException e) _q=ua;I&  
{ NGVl/Qd  
e.printStackTrace (); $c}-/U 8  
} JUd Q Q  
R/Z zmb{  
^vha4<'-qG  
return n; MkX=34oc^  
} 2./;i>H[u  
]3]=RuQK2  
ciGJtD&P  
} (0u(<qA\  
")@#B=8+3^  
W(\ ^6S)  
/* ED^0t  
**SiteInfoBean.java VCQo3k5 {  
*/ >p 9~'  
package NetFox; 1:22y:^j  
xq<X:\O  
RZP7h>y6@  
public class SiteInfoBean { do:IkjU~  
T( fcE  
bk:mk[  
private String sSiteURL; //Site's URL y3OF+;E  
private String sFilePath; //Saved File's Path y~^-I5!_ u  
private String sFileName; //Saved File's Name bW^C30m  
private int nSplitter; //Count of Splited Downloading File KZ@'NnQ  
b)@rp  
tn}MKo  
public SiteInfoBean() L :Ldk  
{//nSplitter的缺省值为5 q5{h@}|M  
//default value of nSplitter is 5 DB3qf>@?  
this("","","",5); "/Pq/\,R|  
} EO%"[k  
?z&5g-/b  
iF Zqoz  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qKTzigjj  
{ -tfUkGdx;l  
sSiteURL= sURL; -ARks_\  
sFilePath = sPath; hlmeT9v{  
sFileName = sName; t~|J2*9l  
this.nSplitter = nSpiltter; &O#,"u/q`  
<iB5&  
y/+ IPR  
} psUT2  
sE&1ZJ]7  
+t3o5&  
public String getSSiteURL() Kc, i$FH  
{ wf`A&P5tF  
return sSiteURL; (e Ssx/  
} 6V*,nocL_+  
R3%%;`c=  
SDB \6[D  
public void setSSiteURL(String value) Ph8@V}80"Y  
{ 4w)>}  
sSiteURL = value; {@6:kkd  
} 3 &mpn,  
t YxN^VqU  
nW}jTBu_K+  
public String getSFilePath() &gKDw!al  
{ a~ dgf:e`  
return sFilePath; tQas_K5  
} IqiU  
vn!5@""T  
B oxtP<C"  
public void setSFilePath(String value) ea]qX6)UZ  
{ k||dX(gl  
sFilePath = value; ?U+hse3e~  
} `!$6F:d_l  
6l[ v3l"t  
lX.-qCV"B  
public String getSFileName() *ow`}Q  
{ =fJU+N+<  
return sFileName; {* P[dyu  
} %P D}VF/Y  
}xBDyr63  
_QEw=*.<  
public void setSFileName(String value) (Gw*x sn1  
{ ;!G#Y Oe  
sFileName = value; +80bG(I_  
} l i)6^f#  
1YQYZ^11  
IT{c:jo1{`  
public int getNSplitter() [N Afy~X*  
{ ^2);*X>  
return nSplitter; v bn=ywz  
} n}_}#(a  
tH4 q*\U  
DxwR&S{  
public void setNSplitter(int nCount) n~]"sTC}&  
{ =yz"xWH  
nSplitter = nCount; 3}!u8,P  
} 8lzoiA_9  
} `g3AM%3  
G;flj}z  
`FQ]ad Fz  
/* LWm1j:0  
**Utility.java B{R[z%Y  
*/ l)*(UZ"  
package NetFox; u*): D~A  
q)L4*O  
2.I|8d[  
public class Utility { n@xQ-v  
?tL'  X  
`-.2Z 0  
public Utility() )~)l^0X  
{ Y(bB7tR  
Lc5zu7ncg  
\fUX_0k9,  
} bsDA&~)s  
^h$*7u"^y  
//线程睡眠 &>C+5`bg  
public static void sleep(int nSecond) 5{k,/Z[L  
{ xi(1H1KN5B  
try{ wpuK?fP  
Thread.sleep(nSecond); -f&vH_eK  
} erW2>^My  
catch(Exception e) ,AweHUEn  
{ J)Y`G4l2@  
e.printStackTrace (); <O 0Q]`i  
} 84.L1|k  
} /nQuM05*Z  
~Ym _ {  
//日志 T2S_> #."l  
public static void log(String sMsg) XDJE]2^52?  
{  e|!'  
System.err.println(sMsg); EN\cwa#FU  
} )g dLb}  
UjQz   
Hs'~) T  
public static void log(int sMsg) i,r:R g~  
{ P0}{xq'k9v  
System.err.println(sMsg); 88v8lt;R  
} 2P^|juc)sU  
} Sp5:R75vI  
wpM2{NTP  
Kh\ 7%>K#  
/* Pgr2 S I  
**TestMethod.java 9=ygkPY  
*/ AJ7^'p9Y  
package NetFox; MGm*({%  
XQ}J4J~Vm  
'Gl~P><e  
public class TestMethod { H%@f ^  
|qn 2b=  
/S"jO [n9b  
public TestMethod() 8xO   
{ ///xx/weblogic60b2_win.exe }w$2,r gA  
try{ hJ{u!:4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }8x+F2i  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ud `- w  
SiteFileFetch fileFetch = new SiteFileFetch(bean); vd[7Pxe  
fileFetch.start(); 9Vm1q!lE  
} %m |I=P  
catch(Exception e){e.printStackTrace ();} s;9Du|0f^  
.g*N +T6O  
6i[Ts0H%<!  
} mp8GHV  
/>S^`KSTM  
ae sk.  
public static void main(String[] args) gQ{ #C'  
{ `xBoNQai  
new TestMethod(); ;bB#P g  
} M9W zsWM  
} Pz2 b  
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