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http断点续传简单实现(java)

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/* }D Z)W0RDe  
**SiteFileFetch.java `i9N )3 X  
*/ 7Zo&+  
package NetFox; PE|PwqX  
import java.io.*; =g >.X9lr  
import java.net.*; Pu-p7:99;'  
RP(a,D|  
Hw y5G ;  
public class SiteFileFetch extends Thread { JxnuGkE0[#  
l:q8Pg)  
P3i^S_  
SiteInfoBean siteInfoBean = null; //文件信息Bean "* +\KPCU  
long[] nStartPos; //开始位置 TbMdQbj}  
long[] nEndPos; //结束位置 !5? m  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?Q;kZmQl  
long nFileLength; //文件长度 )tScc*=8  
boolean bFirst = true; //是否第一次取文件 -.^3;-[  
boolean bStop = false; //停止标志 ):^ '/e  
File tmpFile; //文件下载的临时信息 Ny.*G@&  
DataOutputStream output; //输出到文件的输出流 _yNT=#/  
LSSW.Oz2L  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) W"dU1]  
public SiteFileFetch(SiteInfoBean bean) throws IOException pXve02b1B  
{ (1rJFl!  
siteInfoBean = bean; TF%3uH  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {x7=;-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); qw5&Y$((  
if(tmpFile.exists ()) E2kW=6VO>|  
{ ;*W=c   
bFirst = false; TeKC} NW  
read_nPos(); H_Iim[v#  
} 5dqQws-,?1  
else 8^8>qSD1  
{ qw|JJ  
nStartPos = new long[bean.getNSplitter()]; o>@=N2n  
nEndPos = new long[bean.getNSplitter()]; -MDO Zz\  
} )@!~8<_"  
HOq4i !  
<b6s&"%=  
7AI3|Ts]p  
} J`YnT  
@+iC/  
4 #aqz9k  
public void run() #fwzFS \XL  
{ I ca3  
//获得文件长度 mm_^gQ,`  
//分割文件 xIM8  
//实例FileSplitterFetch kxygf9I!;  
//启动FileSplitterFetch线程 qx Wgt(Os  
//等待子线程返回 "Ys_ \  
try{ $4DFgvy$  
if(bFirst) I<c@uXXV;!  
{ kmmL>fCV"M  
nFileLength = getFileSize(); "|F. 'qZrm  
if(nFileLength == -1) 3b+7^0frY#  
{ PP!l  
System.err.println("File Length is not known!"); 8oa)qaG1  
} ZyHIMo|  
else if(nFileLength == -2) tB GkRd!  
{ wTHK=n\i  
System.err.println("File is not access!"); 9!5b2!JL  
} jaK'W  
else &aY/eD  
{ 5woIGO3X  
for(int i=0;i<nStartPos.length;i++) ?hxK/%)  
{ y>@v>S  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); RlU;v2Kch  
} B{;11 u  
for(int i=0;i<nEndPos.length-1;i++) :-$cdZ3E  
{ 2IKxh  
nEndPos = nStartPos[i+1]; tDEXm^B2Sv  
} 9cVn>Fb  
nEndPos[nEndPos.length-1] = nFileLength; EW ~*@H  
} fB_4f{E  
} V/`#B$6  
l{nB.m2  
`x2fp6  
//启动子线程 qnabwF  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^?E^']H)5u  
for(int i=0;i<nStartPos.length;i++) '&RZ3@}+  
{ B1x'5S;Bq  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {'h)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c zZrP"  
nStartPos,nEndPos,i); I h5/=_n  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $|>6z_3%  
fileSplitterFetch.start(); 5OPS&:  
} ?+bTPl;%'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), | \Ab L!u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7J0 ^N7"o  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !8wZw68"  
nEndPos = " + nFileLength); yonJd  
// fileSplitterFetch[nPos.length-1].start(); dD[v=Z_  
!}iL O0  
`DI{wqV9  
//等待子线程结束 <FXQxM5"  
//int count = 0; g ^D)x[  
//是否结束while循环 ;~}- AI-  
boolean breakWhile = false; :X3rd|;kc  
\%w7D6dEZ  
^ze@#Cp  
while(!bStop) j'G"ZPw1  
{ r$b:1C~  
write_nPos(); !JT< (I2  
Utility.sleep(500); 9QX&7cs&[  
breakWhile = true; ~z\pI|DQ  
wlm3~B\64  
/IGrp.}  
for(int i=0;i<nStartPos.length;i++) A>qd2  
{ 1gF*Mf_7  
if(!fileSplitterFetch.bDownOver) M3hy5 j(b  
{ 0|WOReskK  
breakWhile = false; 3c1o,2  
break; 2z.k)Qx!Z  
} ^JYF1   
} #n U@hOfg  
if(breakWhile) gg lNpzj  
break; ~J8cS  
$=\oJ-(!@S  
W)6U6  
//count++; OU0xZ=G  
//if(count>4) d/0/$Bz}P  
// siteStop(); X !&"&n  
} b|X>3(  
y}(_SU  
FiV^n6-F`  
System.err.println("文件下载结束!"); >GdLEE'w  
} \_iH4<#>  
catch(Exception e){e.printStackTrace ();} 7VEt4  
} 5O;/ lX!u  
[i,5>YIk  
yrxx+z|wR  
//获得文件长度 0hH Iz4(  
public long getFileSize() m _t(rn~f6  
{ |_Naun=+~  
int nFileLength = -1; o'x_g^ Y  
try{ nr 'YWW  
URL url = new URL(siteInfoBean.getSSiteURL()); >i><s>=I`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "wc`fg"3  
httpConnection.setRequestProperty("User-Agent","NetFox"); +^^S'mP8  
b&hF')_UOz  
]pM5?^<~  
int responseCode=httpConnection.getResponseCode(); "k>{b:R|  
if(responseCode>=400) S*~Na]nS0  
{ ]1/W8z%  
processErrorCode(responseCode); 4aIlzaA  
return -2; //-2 represent access is error |R_xY=z?  
} Vp- n(Z  
6E*Zj1KX  
 3L 1lq .  
String sHeader; )w }*PL  
e3HF"v]2!  
fzGZ:L  
for(int i=1;;i++) !5g)3St  
{ d\1:1ucV  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j`LT`p"9S  
//Utility.log(in.readLine()); |Oj,S|Z:  
sHeader=httpConnection.getHeaderFieldKey(i); t<KEx^gb  
if(sHeader!=null) &?`d8\z  
{ ; @[.$Q@I  
if(sHeader.equals("Content-Length")) (&N$W&  
{ ,b2O^tJF#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); P:zEx]Y%  
break; 1*c0\:BQ;z  
} Tko CyD9  
} Y(Z(dV!Po  
else rRA_'t;uK  
break; nU">> 1!U  
} d-A%ZAkE]  
} >mGGJvTx  
catch(IOException e){e.printStackTrace ();} `Tm8TZd66  
catch(Exception e){e.printStackTrace ();} zm_hLk  
g,z&{pZch  
I'6 ed`|  
Utility.log(nFileLength); \nWzn4f  
hg86#jq%  
K4VPmkG  
return nFileLength; Is,*qrl :  
} eBLHT  
<O`q3u'l  
TZ[F u{gZ  
//保存下载信息(文件指针位置) c'wU O3S  
private void write_nPos() U4mh!  
{ duiKFNYN  
try{ 'nmYB:&!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *}Ae9  
output.writeInt(nStartPos.length); +Fy- ~Mq  
for(int i=0;i<nStartPos.length;i++) Eb{4.17b  
{ LcQ\?]w`]  
// output.writeLong(nPos); ND99 g  
output.writeLong(fileSplitterFetch.nStartPos); `6l24_eKf  
output.writeLong(fileSplitterFetch.nEndPos); se*pkgWbz  
} .+ yJh  
output.close(); LeRh (a`=$  
} lw/ m0}it  
catch(IOException e){e.printStackTrace ();} 4*ty&s=5OJ  
catch(Exception e){e.printStackTrace ();} c,u$tnE)  
} Liz 6ob  
8xGkh?%  
"78cl*sD  
//读取保存的下载信息(文件指针位置) L>R!A3G1  
private void read_nPos() 1{uDHB  
{ b} q(YgH<  
try{ V.OoZGE>]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Nr*ibtz|D  
int nCount = input.readInt(); p%M(G#gOgP  
nStartPos = new long[nCount]; zs]>XO~Jg  
nEndPos = new long[nCount]; wxr}*Z:ZMa  
for(int i=0;i<nStartPos.length;i++) qLktMp_  
{ 6I6ZVSxb  
nStartPos = input.readLong(); zDQ\PZ~  
nEndPos = input.readLong(); b^=8%~?%4  
} #ui%=ja[:~  
input.close(); `\/Wah}I  
} jWb\"0)  
catch(IOException e){e.printStackTrace ();} %/,Uk+3p  
catch(Exception e){e.printStackTrace ();} 4VL!U?dk  
} Se]t;7j  
V[2<ha[n>  
14)kKWG  
private void processErrorCode(int nErrorCode) U:\oGa84A  
{ -<VF6k<  
System.err.println("Error Code : " + nErrorCode); u BW  
} Ml_:Q]kl^  
P^{`d_[K%  
?2bE=|  
//停止文件下载 :-jP8X  
public void siteStop() mm9S#Ya  
{ EPUJa~4  
bStop = true; [7t0[U~3?  
for(int i=0;i<nStartPos.length;i++) <a/ZOuBzZ  
fileSplitterFetch.splitterStop();  3kzGL  
l#(g&x6J  
~'YSVx& )  
} I]S(tx!  
} looPO:bo^  
//负责部分文件的抓取 U=*q;$L#  
**FileSplitterFetch.java 0O 9 Lg}  
*/ :ftyNaq'  
package NetFox; L[9+xK^g  
Z~R/ p;@  
ki/Lf4  
import java.io.*; (fjXp75  
import java.net.*; :\HN?_?{4  
 9%hB   
-T="Ml &  
public class FileSplitterFetch extends Thread { *{n,4d\..  
fJN9+l  
(h(ZL9!  
String sURL; //File URL sT8kVN|Uv  
long nStartPos; //File Snippet Start Position %Zi,nHg8  
long nEndPos; //File Snippet End Position mjJlXA  
int nThreadID; //Thread's ID SEn8t"n  
boolean bDownOver = false; //Downing is over a*ixs'MJ  
boolean bStop = false; //Stop identical T?$?5  
FileAccessI fileAccessI = null; //File Access interface Z-r0 D  
gZuR4Ti  
hCx#Heh  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ViC76aJ  
{ (TK cSVR  
this.sURL = sURL; G37L 9IG-M  
this.nStartPos = nStart; R5YtCw]i=  
this.nEndPos = nEnd; Q0cf]  
nThreadID = id; xuC6EK+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 G`<1>%" F  
} 53#5p;k  
L?5t <`#lw  
iO#xIl<  
public void run() a\.?{/  
{ ="*C&wB^  
while(nStartPos < nEndPos && !bStop) \fGYJ37  
{ JSP8Lu"n  
>L3p qK   
7PPsEU:rf  
try{ &5CeRx7%  
URL url = new URL(sURL); ]$X=~>w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); . *+7xL  
httpConnection.setRequestProperty("User-Agent","NetFox"); pc(9(. |  
String sProperty = "bytes="+nStartPos+"-"; FP cvkXQD  
httpConnection.setRequestProperty("RANGE",sProperty); J-,X0v"  
Utility.log(sProperty); J!qEj{  
)FiU1E  
.St h  
InputStream input = httpConnection.getInputStream();   rs KE  
//logResponseHead(httpConnection); A^jm<~  
HAOrwJFqU  
0R{R=r]  
byte[] b = new byte[1024]; (W6\%H2u  
int nRead; J~ rC  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O? <_,-.  
{ {twf7.eY  
nStartPos += fileAccessI.write(b,0,nRead); v*p)"J *  
//if(nThreadID == 1) tz> X'L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0{@Ovc  
} y")>"8H  
G&B}jj  
 y3$\ m  
Utility.log("Thread " + nThreadID + " is over!"); r]vBr^kq  
bDownOver = true; DD3yl\#,  
//nPos = fileAccessI.write (b,0,nRead); Fgq*3t  
} $e,!fB;B  
catch(Exception e){e.printStackTrace ();} x=<>%m5R  
} sm <kb@g  
} KPK!'4,cu  
3om7LqcRo  
biuo.OG]  
//打印回应的头信息 RB@gSHOc?  
public void logResponseHead(HttpURLConnection con) @k;3$  
{ DxG'/5jQ[  
for(int i=1;;i++) aYX'&k `  
{ ?-p aM5Q+  
String header=con.getHeaderFieldKey(i); "K=)J'/n  
if(header!=null) bpCe&*\6K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rW .0_*  
Utility.log(header+" : "+con.getHeaderField(header)); 6:X\vw  
else iC\=U  
break; lJ2/xE]  
} S;kc{?   
} KAaeaiD  
`qEm5+`  
DEuW'.o>  
public void splitterStop() !KW)*  
{ ImW~Jy  
bStop = true;  Ue Tp,  
} ? =Qg  
clV/i&]Qa  
k18V4ATE]  
} vK/Z9wR*05  
WWz ns[$f  
oMf h|B  
/* )^xmy6k  
**FileAccess.java 1a4$. {  
*//文件访问(定位,写) !0_Y@>2  
package NetFox; q&x#S_!  
import java.io.*; JB}h }nb  
WWs>@lCK  
mjc:0hH  
public class FileAccessI implements Serializable{ 09i[2n;O  
7guxkN#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Unk+@$E&  
RandomAccessFile oSavedFile; &?pAt30K:  
long nPos; bm|8Jbsb&  
qa#F}aGd  
^DJ U99  
public FileAccessI() throws IOException T!$HVHh&,}  
{ 2?&ptN) `N  
this("",0); `84yGXLK  
} x$4'a~E  
XAkl,Y  
)^3655mb  
public FileAccessI(String sName,long nPos) throws IOException o*8 pM`uw  
{ W{2y*yqY  
oSavedFile = new RandomAccessFile(sName,"rw"); .w"O/6."  
this.nPos = nPos; breVTY7 S  
oSavedFile.seek(nPos); DSa92:M}  
} Z 0^d o  
>eI(M $  
epe}^Pl  
public synchronized int write(byte[] b,int nStart,int nLen) Q4 S8NqE  
{ (CwaO m{g  
int n = -1; an@Ue7  
try{ 4\iQ%fb  
oSavedFile.write(b,nStart,nLen); ;bmd<1  
n = nLen; J>&GP#7}  
} 4(](' [M  
catch(IOException e) HX^ P9jXT  
{ =2 5 "q Jr  
e.printStackTrace (); )Qp?LECrt  
} "[ ,XS`  
rZ7 Ihof  
%&NK|M+n  
return n; ^hJ ,1{o  
} efm<bJB2  
0cVXUTJ|W  
K>~l6  
} S6I8zk)Z4  
n_Dhq(.  
F[Up  
/* cgAcAcmY  
**SiteInfoBean.java  }P#gXG  
*/ DO; 2)ZQ%  
package NetFox; L"0L_G  
Fh;(1X75I  
'-_PO|}  
public class SiteInfoBean { ,y @3'~  
eA_4,"{  
4v7RX  
private String sSiteURL; //Site's URL 4B 6Aw?  
private String sFilePath; //Saved File's Path .Dz /MSl  
private String sFileName; //Saved File's Name 8X5XwFf}  
private int nSplitter; //Count of Splited Downloading File #(G&%I A|;  
^TGHWCK!t  
lw{|~m5`  
public SiteInfoBean() c+c^F/  
{//nSplitter的缺省值为5 !h~\YE)  
//default value of nSplitter is 5 {,ljIhc,  
this("","","",5); XhiC'.B_  
} kzT'  
* G4;  
0v?,:]A0E  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,v+SD\7|  
{ gf@Dy6<  
sSiteURL= sURL; {cFei3'q  
sFilePath = sPath; dLq!t@?iu>  
sFileName = sName; TMrmyvv  
this.nSplitter = nSpiltter;  '}=M~  
5s9~rm  
qZ.\GHS  
} 9"e!0Q40  
Y|L57F  
zc#`qa:0  
public String getSSiteURL() ]SI`fja/  
{ ] Yy Sf  
return sSiteURL; P!/8   
} uQlVzN.?  
Fk\xq`3'c  
QK\z-'&n  
public void setSSiteURL(String value) * gnL0\*  
{ P'+*d#*S  
sSiteURL = value; ?5D7n"jY  
} >JhQ=j  
6{6tg>|L)  
%F7k| Na  
public String getSFilePath() Yp8$0KK  
{ FpEdwzBb<  
return sFilePath; ur|2FS7  
} hI yfF  
rBL)ct  
_cB~?c  
public void setSFilePath(String value) /[p4. FL  
{ ?w+T_EH  
sFilePath = value; u|C9[(  
} f]EHDcC3X  
sQkP@Y  
[,c>-jA5  
public String getSFileName() NTC,Vr\A  
{ S/4k fsN  
return sFileName; !PgYn  
} d@<XR~);  
$FoNEr&q  
R *U>T$  
public void setSFileName(String value) RK,~mXA  
{ Z7Kc`9.0|  
sFileName = value; 5R4 dN=L*1  
} Gs%kqD{=  
iR9iI!+;N  
B0:O]Ax6.^  
public int getNSplitter() KLk37IY2\  
{ JGtdbD?Fw  
return nSplitter; 'oTF$3n  
} Y<B| e91C  
^6=nL<L  
B\6\QQ;rUo  
public void setNSplitter(int nCount) hE;  
{ 5 Z@Q ^  
nSplitter = nCount; !@Ox%vK  
} B`vV[w?  
} tNjrd}8s  
1@am'#<  
/N $T[  
/* rO C~U85  
**Utility.java Dbgw )n*2  
*/ (b(iL\B$D=  
package NetFox; Ne=D $o  
=hA/;  
i}!CY@sW  
public class Utility { qU"+0t4  
$V[ob   
76 y}1aa  
public Utility() M8h9i2  
{ c9Cp!.#*E  
*ce h ]v  
`0L!F"W  
} DV. m({?  
@~"0|,6VC  
//线程睡眠 /as1  
public static void sleep(int nSecond) P^ a$?  
{ yJ^}uw  
try{ Q$3%aR-2  
Thread.sleep(nSecond); P%1s6fjU  
} 5n_<)Ycj  
catch(Exception e) YcIk{_N3  
{ /t816,i  
e.printStackTrace (); t ({:TQ  
} ]1klfp,`  
} NJ|8##Z>  
B$fL);l-  
//日志 1e }wDMU(  
public static void log(String sMsg) V< J~:b1V  
{ k}/0B  
System.err.println(sMsg); ,ujoGSx}  
} lOVsp#  
(mv8_~F0  
Z yIn>]{  
public static void log(int sMsg) lO:[^l?F  
{ /Qbt  
System.err.println(sMsg); F77~156  
} eOS#@6U=u  
} N/Z<v* i"  
g4Tc (k#  
+YP,LDJ!v  
/* N O'-HKHj  
**TestMethod.java [~x Q l  
*/ Oq[tgmf  
package NetFox; CYz]tv}g:  
4/$]wK`  
3^8%/5$v  
public class TestMethod { CT/`Kg_  
P>:"\I[  
`/"TYR%  
public TestMethod() Jcm" i ~  
{ ///xx/weblogic60b2_win.exe #*5A]"k  
try{ n:HF&j4C,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); gQ& FO~cr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); p!173y,nL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @zE_fL  
fileFetch.start(); CB|Z~_Bm  
} gV A$P  
catch(Exception e){e.printStackTrace ();} KN5.2pp  
[}.OlR3)  
]GRPxh  
} nNf/$h#;O  
;|66AIwDe  
68d(6?OgW  
public static void main(String[] args) \!`*F :7]-  
{ |NL$? %I  
new TestMethod(); XBCz\f  
} \ 3ha  
} {,,w5/k^  
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