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http断点续传简单实现(java)

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/* uJx"W  
**SiteFileFetch.java -50 HB`t  
*/ 3K&4i'}V  
package NetFox; bawJ$_O_  
import java.io.*; \y6OUM2y  
import java.net.*; eAUcv`[#p  
!f>d_RG  
a8u 9aEB  
public class SiteFileFetch extends Thread { xX3'bsN  
.iCDXc{#  
4p%A8%/q  
SiteInfoBean siteInfoBean = null; //文件信息Bean Gir#"5F  
long[] nStartPos; //开始位置 MUOa@O,  
long[] nEndPos; //结束位置 E r/bO  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5tJ,7Y'  
long nFileLength; //文件长度 tqAd$:L  
boolean bFirst = true; //是否第一次取文件 +[\eFj|=  
boolean bStop = false; //停止标志 G 6VF>2  
File tmpFile; //文件下载的临时信息 Vc^HVyAx@n  
DataOutputStream output; //输出到文件的输出流 )%rg?lI  
u4z&!MT}  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) i'stw6*J  
public SiteFileFetch(SiteInfoBean bean) throws IOException "G >3QL+O|  
{ Q 4CjA3  
siteInfoBean = bean; 6nhMP$h  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fQrhsuCrC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z\[N!Zt|  
if(tmpFile.exists ()) q'pK,uNW  
{ [dtbkQt,c  
bFirst = false; =4GSg1Biy  
read_nPos(); |6G m:jV  
} +q6ydb,  
else imQUR C  
{ =b;>?dP  
nStartPos = new long[bean.getNSplitter()]; I H$0)g;s  
nEndPos = new long[bean.getNSplitter()]; b~dIk5>O  
} Q1V9PRZX  
9nu3+.&P  
2r$#m*  
IwGqf.!.>  
} NM)k/?fA  
H>r!i 4l  
3_JCU05H}  
public void run() TW !&p"Us+  
{ (&$VxuJ+6y  
//获得文件长度 !lo/xQ<  
//分割文件 }b1cLchl  
//实例FileSplitterFetch iy""(c  
//启动FileSplitterFetch线程 :JlP[I  
//等待子线程返回 6TP7b|  
try{ 4Llo`K4  
if(bFirst) lKk/p^:  
{ d[rv1s>i  
nFileLength = getFileSize(); a>\vUv*  
if(nFileLength == -1) R^{)D3  
{ 8H[:>;S I  
System.err.println("File Length is not known!"); HF|oBX$_  
} w+1Gs ;  
else if(nFileLength == -2) @p\}pY$T  
{ );-~j  
System.err.println("File is not access!"); m%?V7-9!k  
} @F(mi1QO  
else X.`~>`8  
{ !3T&4t  
for(int i=0;i<nStartPos.length;i++) x@8a''  
{ KZ~*Nz+H2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); R$zH]  
} 6q 2_WX  
for(int i=0;i<nEndPos.length-1;i++) q -8t'7  
{ 3Hf0MAt  
nEndPos = nStartPos[i+1]; .s$z/Jv  
} D7_*k%;@  
nEndPos[nEndPos.length-1] = nFileLength; {v3P9s(  
} yDNOtC|  
} HSq}7S&U  
k4 F"'N   
Cu6%h>@K$  
//启动子线程 $1SUU F\.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];   TX  
for(int i=0;i<nStartPos.length;i++) s&'QN=A  
{ a22XDes=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q+,Q<2J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Jmx Ko+-  
nStartPos,nEndPos,i); 4@xE8`+b G  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1?Z4 K /  
fileSplitterFetch.start(); ;;&}5jcV  
} -W>'^1cR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F-6c_!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \TU3rk&X  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", y(K" -?  
nEndPos = " + nFileLength); ~i 7^P9  
// fileSplitterFetch[nPos.length-1].start(); ID/ F  
w3$   
b+Br=Fv"T  
//等待子线程结束 ut r:J  
//int count = 0; Y))NK'B5  
//是否结束while循环 ^j7azn  
boolean breakWhile = false; *2jK#9"MP  
r&FDEBh  
Yw0[[N<SW  
while(!bStop) Ewg:HX7<(  
{ R##~*>#  
write_nPos(); 43=,yz2Ef  
Utility.sleep(500); ,a#EW+" Z  
breakWhile = true; 5atYOep  
8_N]e'WUh  
.1LCXW=  
for(int i=0;i<nStartPos.length;i++) $8BPlqBIZ  
{  W%\C_  
if(!fileSplitterFetch.bDownOver) r7qh>JrO  
{ E lUEteZ  
breakWhile = false; 6uR^%W8]  
break; %j7XEh<'  
} H= X|h)  
} zP<pEI  
if(breakWhile) <I;2{*QI2  
break; c*~]zR>s!  
13Lr }M&  
%iw3oh&Fkm  
//count++; 63A}TBC  
//if(count>4) }u1O#L}F5  
// siteStop(); @e{^`\l=<  
} ^aW Z!gi  
D+>1]ij  
0 iJue &  
System.err.println("文件下载结束!"); yq$,,#XDD=  
} tor!Dl@Mo  
catch(Exception e){e.printStackTrace ();} aM;W$1h  
} A~mum+[5  
#Skv(IL  
H*r>Y  
//获得文件长度 4"Hye&O  
public long getFileSize() M8u<qj&<O  
{ N?.%?0l  
int nFileLength = -1; 9+pmS#>_  
try{ IH"6? 9nd  
URL url = new URL(siteInfoBean.getSSiteURL()); Nv"EV;$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .aflsUD  
httpConnection.setRequestProperty("User-Agent","NetFox"); yxc=Z0~1  
V(E/'DR  
$.bBFWk  
int responseCode=httpConnection.getResponseCode(); h\'n**f_x  
if(responseCode>=400) +U@<\kIF  
{ 4!wR_@W^El  
processErrorCode(responseCode); MuSUKBhM  
return -2; //-2 represent access is error &zo|Lfe  
} Sf r&p>{,  
@/1w4'M  
iJ~Vl"|m  
String sHeader; GQ-Rtn4v  
nWHa.H#  
=lpQnj"  
for(int i=1;;i++) @K!&qw  
{ c ;'[W60  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y3=_ec3w  
//Utility.log(in.readLine()); CoA6  
sHeader=httpConnection.getHeaderFieldKey(i); 8}(]]ayl  
if(sHeader!=null) xL" |)A =  
{ I&YSQK:b  
if(sHeader.equals("Content-Length")) )K2HK&t:  
{ & j+oJasI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); KSrx[q  
break; ?y!E-&  
} $r3i2N-I  
} ^53r/V}%  
else c}0@2Vf  
break; wT{nu[=GH*  
} LWt&3  
} /Js7`r=Rx  
catch(IOException e){e.printStackTrace ();} CH<E,Z C1T  
catch(Exception e){e.printStackTrace ();} b?'yAXk  
+j4"!:N}B  
'f?$"U JF  
Utility.log(nFileLength); {.?/)  
71{p+3Z&  
k|!EDze43?  
return nFileLength; O &-wxJ]S  
} R`~z0 d.  
9cj9SB4  
LA)[ip4  
//保存下载信息(文件指针位置) %?Ev|:i`@  
private void write_nPos() ~T89_L  
{ mN19WQ(r  
try{ 6!(@@^7{*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q0ON9gqqv  
output.writeInt(nStartPos.length); \0gM o&  
for(int i=0;i<nStartPos.length;i++) #KiRfx4G  
{ }3L@J8:D"  
// output.writeLong(nPos); A\.GV1  
output.writeLong(fileSplitterFetch.nStartPos); 'Un " rts  
output.writeLong(fileSplitterFetch.nEndPos); )[|3ZP`  
} s4uhsJL V$  
output.close(); k{Aj^O3gD  
} icgSe:Ci  
catch(IOException e){e.printStackTrace ();} FJ6u.u  
catch(Exception e){e.printStackTrace ();} }:~x7|~s:  
} L:'J Bhg  
5hy""i  
_:"<[ >9  
//读取保存的下载信息(文件指针位置) ,xxR\}  
private void read_nPos() 9\DQ>V TQ  
{ `9b7>Nn<  
try{ fP `b>]N_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1N>|yQz  
int nCount = input.readInt(); aUtnR<6  
nStartPos = new long[nCount]; uF3qD|I\  
nEndPos = new long[nCount]; t0T"@t#c  
for(int i=0;i<nStartPos.length;i++) m RO~aD!N  
{ x a06i#  
nStartPos = input.readLong(); (#E.`e1#6  
nEndPos = input.readLong(); smDw<slC  
} u5%7}<nNi  
input.close(); 5EfS^MRf\n  
} G@Z?&"    
catch(IOException e){e.printStackTrace ();} 7?%k7f  
catch(Exception e){e.printStackTrace ();} xcf%KXJf6  
} oGRhnP'PF+  
M )2`+/4  
x HhN  
private void processErrorCode(int nErrorCode) ;{%\9nS  
{ {b   
System.err.println("Error Code : " + nErrorCode); ~Wa6J4B{K  
} _n` a`2C|m  
i|m3mcI%2  
6ZQwBS0Y  
//停止文件下载 Q(oN/y3,  
public void siteStop() 7[}xP#Z  
{ KPj\-g'A  
bStop = true; =HlQ36;*  
for(int i=0;i<nStartPos.length;i++) X]dwX%:Z!j  
fileSplitterFetch.splitterStop(); w2'f/  
 pn5Q5xc  
K]0JC/R6(@  
} 5)MS~ii  
} }dd8N5b  
//负责部分文件的抓取 #hsx#x||  
**FileSplitterFetch.java EL9]QI  
*/ /Dj=iBO  
package NetFox; &mtJRfnu  
^cz(}N 6&  
k<\$OoOZ  
import java.io.*; &Ob!4+v/GP  
import java.net.*; p ObX42  
k-{<=>uM  
H,u<|UMM_  
public class FileSplitterFetch extends Thread { e F3,2DD C  
{ >)#HD  
G8Y<1%`<  
String sURL; //File URL % V8U (z  
long nStartPos; //File Snippet Start Position #I bp(  
long nEndPos; //File Snippet End Position 2P@sn!*{1  
int nThreadID; //Thread's ID F 70R1OYU  
boolean bDownOver = false; //Downing is over pxh"B\"4*  
boolean bStop = false; //Stop identical trp0 V4b8  
FileAccessI fileAccessI = null; //File Access interface [S>2ASj  
~"kb7Fxp  
Ot6aRk  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <t \H^H!  
{  N#a$t&  
this.sURL = sURL; DRi<6Ob  
this.nStartPos = nStart; `,(,t n_  
this.nEndPos = nEnd; ZGKu>yM  
nThreadID = id;  q;][5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :dQ B R  
} G%W8S \  
/Y7<5!cS  
j4uvS!  
public void run() -- c"0,7  
{ sv&;Y\2c  
while(nStartPos < nEndPos && !bStop) B2'i7P s  
{ h* u  
tE`u(B,  
[c|]f_ZdK  
try{ &b fA.& `  
URL url = new URL(sURL); Pf\D-1gi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m4l& eEp  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5?F__Hx*2  
String sProperty = "bytes="+nStartPos+"-"; Bx4w)9+3  
httpConnection.setRequestProperty("RANGE",sProperty); U_n9]Z  
Utility.log(sProperty); ([m mPyp>L  
Lja>8m  
xY^ %&n  
InputStream input = httpConnection.getInputStream(); 75/(??2  
//logResponseHead(httpConnection); f m)pulz  
'g m0)r  
:6 Lx@  
byte[] b = new byte[1024]; Yd=>K HVD  
int nRead; qfMo7e@6*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [8*jw'W|[  
{ l^pA2yh|  
nStartPos += fileAccessI.write(b,0,nRead); li}1S  
//if(nThreadID == 1) z;|A(*Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `</ff+Q6  
} <#u=[_H  
|w<H!lGe!$  
2;DuHO1  
Utility.log("Thread " + nThreadID + " is over!"); ~^r29'3  
bDownOver = true; =06gj)8  
//nPos = fileAccessI.write (b,0,nRead); UVd7 JGR  
} U<_3^  
catch(Exception e){e.printStackTrace ();} =pS5uR~  
} fj;y}t1E]  
} )W;o<:x3  
4;0lvDD  
5n9B?T8C  
//打印回应的头信息 P'Ux%Q+B>  
public void logResponseHead(HttpURLConnection con) UJ CYs`y  
{ (2^gVz=j  
for(int i=1;;i++) 2[O&NdP\Zk  
{ /2=#t-p+  
String header=con.getHeaderFieldKey(i); GycSwQ ,  
if(header!=null) 0+kH:dP{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); { + Zd*)M[  
Utility.log(header+" : "+con.getHeaderField(header)); Pa V@aM~3  
else `\#B18eU  
break; `OXpU,Z 6U  
} B1>/5hV}  
} hPUYyjXPB  
"NXB$a!:  
IDB+%xl#S  
public void splitterStop() D*gFV{ Ws  
{ =E.t`x=  
bStop = true;  ]%wVHC  
} N`L0Vd  
=WyZX 7@R  
LE9(fe) fe  
} ebUBrxZX  
1p/3!1  
V@ cM|(  
/* #t: S.A@  
**FileAccess.java $m].8?  
*//文件访问(定位,写) HUv/ ~^<  
package NetFox; C9n?@D;S  
import java.io.*; }%'?p<^M  
hRrn$BdLX  
5qZ1FE  
public class FileAccessI implements Serializable{ JGsx_V1t  
LYz.Ci}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vdx0i&RiL  
RandomAccessFile oSavedFile; %S*{9hm/  
long nPos; WJkZ!O$"j  
d%RC  
| r&k48@  
public FileAccessI() throws IOException T`\x,` ^  
{ t>urc  
this("",0); :U3kW8;UMP  
} qln3 k`  
p?) ;eJtV/  
c#Sa]n  
public FileAccessI(String sName,long nPos) throws IOException /H(? 2IHC  
{ cDFO;Dr  
oSavedFile = new RandomAccessFile(sName,"rw"); %)|9E>fP]N  
this.nPos = nPos; b F"G[pD  
oSavedFile.seek(nPos); %,6#2X nX%  
} %|g>%D3Z?  
TDFkxB>  
#LL?IRH9^  
public synchronized int write(byte[] b,int nStart,int nLen) _aad=BrMK  
{ :Q $K<)[  
int n = -1; 7VqM$I  
try{ /%}*Xh  
oSavedFile.write(b,nStart,nLen); u09:Z{tL;@  
n = nLen; -0$55pa/@:  
} nrxo &9[@n  
catch(IOException e) `\gnl'  
{ E*V`":efS  
e.printStackTrace (); s.N7qO^:E  
} K1r#8Q!t  
8S mCpg  
H:t$'kb`  
return n; K?B{rE Lp  
} b\vKJ2  
)vjh~ybZ  
;V*R*R  
} ]h* c,.  
] >LhkA@V  
Z&1T  
/* ysxb?6  
**SiteInfoBean.java 8\^}~s$$A  
*/ V5sg#|&  
package NetFox; =j5MFX.-o  
-Zf@VW,NI  
;aI[=?<x  
public class SiteInfoBean { 6*B19+-  
?s\:hNNY  
2N~Fg^xB  
private String sSiteURL; //Site's URL m?pstuUK(  
private String sFilePath; //Saved File's Path  "HElB9  
private String sFileName; //Saved File's Name -(bXSBs#  
private int nSplitter; //Count of Splited Downloading File 7'Zky2F  
KIui(n#/  
=XucOli6  
public SiteInfoBean() ej4W{IN~:  
{//nSplitter的缺省值为5 { QHVo#  
//default value of nSplitter is 5 l6YtEHNG  
this("","","",5); /^X/8  
} I/d&G#:~  
Rn`x7(WA  
b$ve sJ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) kbTm^y"  
{ f,V<;s  
sSiteURL= sURL; ;1`fC@rI  
sFilePath = sPath; sYe?M,  
sFileName = sName; R< ,`[*Z  
this.nSplitter = nSpiltter; -8eoNzut  
-=)+dCyB^  
@&%'4j&+  
} 2z6yn?'&L  
\>jLRb|7Ts  
(]0%}$Fo  
public String getSSiteURL() 4}_j`d/8|  
{ uw [<5  
return sSiteURL; *5vV6][  
} M=1nQF2J  
4 Y ;Nm1 @  
6+.uU[x@  
public void setSSiteURL(String value) N^HUijw<  
{ 2 ^mJ+v<  
sSiteURL = value; 9o;^[Ql-  
} _,xc[ 07  
QrB@cK]  
KM}f:_J*lg  
public String getSFilePath() qfL~Wp2E;  
{ Y ;u<GOe  
return sFilePath; 4wID]bKM  
} 5mJJU  
aGJC1x  
1T y<\bZ=  
public void setSFilePath(String value) O4r0R1VQM  
{ xIxn"^'  
sFilePath = value; 6|aKL[%6  
} jGXO\:s O  
ofPHmh`  
UUzYbuS>&l  
public String getSFileName() =NnNN'}  
{ m@"QDMHk.  
return sFileName; #JgH}|&a$  
} W%T>SpFl  
73V|6tmgY  
q}~3C1  
public void setSFileName(String value) ?&|5=>u2}$  
{ *+j* {>E  
sFileName = value; @x"0_Qw  
} ::ajlRZG  
"OQ^U_  
Xe<sJ. &Wf  
public int getNSplitter() ]$Yvj!K*Q  
{ Fs{x(_LOr  
return nSplitter; &j4xgh9  
} a= DcZ_M  
^cczJOxB  
S{;sUGcu  
public void setNSplitter(int nCount) Pl=ZRKn  
{ R%Q@   
nSplitter = nCount; b~'"^ Bts*  
} PV9pa/`@  
} `S6x<J&T\/  
uT}' Y)m  
^Wc@oa`  
/* -j73Wz  
**Utility.java G]+&!4  
*/ ]|MEx{BG-  
package NetFox; A%`[mc]4#  
k\WR  ]  
1#.>a$>  
public class Utility { G '6@+$ppS  
Qp/QaVQ+  
Tav*+  
public Utility() H*[ M\gN$  
{ X:6c}p%,!  
``ou/Z  
JBJhG<J  
} W_kHj}dj,p  
kPVO?uO  
//线程睡眠 LL2=&VK  
public static void sleep(int nSecond) 8g&? Cc  
{ kKAP"'v  
try{  .Nw=[  
Thread.sleep(nSecond); a#>Yh;FA  
} MC<PM6w  
catch(Exception e) _(h&7P9  
{ T(t+ iv  
e.printStackTrace (); A<1hOSCz\  
} n}'=yItVL1  
} c17_2 @N  
_tBTE%sO  
//日志 S<4c r  
public static void log(String sMsg)  /% M/  
{ TMig-y*[  
System.err.println(sMsg); poToeagZ~Q  
} 5\e9@1Rc  
"tB;^jhRs  
JKGc3j,+#  
public static void log(int sMsg) Vm3v-=6  
{ $4/yZaVb  
System.err.println(sMsg); my}-s  
} {vuZ{I Ja  
} KU8J bl*   
E=>FjCsu<-  
.ox8*OO<  
/* %d?cP}V  
**TestMethod.java .7l&1C)i  
*/ *g6n  
package NetFox; P %#<I}0C  
EJsM(iG]~M  
.w0s%T,8}^  
public class TestMethod { cUY`97bn  
<Dwar>}  
;\=M; Zt  
public TestMethod() [N/"5 [  
{ ///xx/weblogic60b2_win.exe h&--,A >  
try{ > U%gctIg  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \'|> p/5I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); JwAYG5W  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fp+gyTnd3  
fileFetch.start(); H[S%J3JI  
} qYlhlHD  
catch(Exception e){e.printStackTrace ();} T~Gvp0r}h  
U-R6xxPZ  
`QyO`y=?[Y  
} {&\jW!&n  
=5kY6%E7c  
X{\F;Cb*  
public static void main(String[] args) `NgAT 3zq  
{ nv@8tdrc  
new TestMethod(); ~c %hWt  
} kic/*v\6@  
} bT^I"  
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