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http断点续传简单实现(java)

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/* 19!;0fe=  
**SiteFileFetch.java {Ja(+NQ  
*/ x7`+T 1IJ  
package NetFox; ;)P=WS:=  
import java.io.*; TqfL Sm|  
import java.net.*; }:;UnE}  
Km,o+9?1gF  
R osU~OK  
public class SiteFileFetch extends Thread { O/d]2<V  
suGd&eP|  
T0)bnjm  
SiteInfoBean siteInfoBean = null; //文件信息Bean )EKWsGNe/  
long[] nStartPos; //开始位置 .jtv Hr}U  
long[] nEndPos; //结束位置 E'(nJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p|dn&<kd  
long nFileLength; //文件长度 *rHz/& ,  
boolean bFirst = true; //是否第一次取文件 _9p79S<+  
boolean bStop = false; //停止标志 d"Wuu1tEY  
File tmpFile; //文件下载的临时信息 -p>1:M <  
DataOutputStream output; //输出到文件的输出流 Q6e7Z-8  
Cg`lQY U  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 1\Pjz Lj  
public SiteFileFetch(SiteInfoBean bean) throws IOException u^CL }t*  
{ ~kSO YvK$'  
siteInfoBean = bean; t*A[v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "bWx<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); lQvgq  
if(tmpFile.exists ()) T:H~Y+qnt  
{ 9&`";dg  
bFirst = false; S7#dyAX8  
read_nPos(); j|N<6GSke  
} a l6y=;\jZ  
else #d/T7c#  
{ ~UNha/nt  
nStartPos = new long[bean.getNSplitter()]; l(}L-:@A  
nEndPos = new long[bean.getNSplitter()]; $8AW  
} $|3zsi2  
84WcaH  
la!U  
-"i $^Q`  
} rXE0jTf:a  
">eled)O  
!IO\g"y~|%  
public void run() b09xf"D  
{ lcjOBu  
//获得文件长度 -qHG*v,  
//分割文件 j6XHH&ZEb  
//实例FileSplitterFetch m.1-[2{8~  
//启动FileSplitterFetch线程 X#ud5h  
//等待子线程返回 v>Kh5H5e~  
try{ g;6/P2w  
if(bFirst) o^* :  
{ pL`Q+}c}  
nFileLength = getFileSize(); #=33TvprR2  
if(nFileLength == -1)  G +41D  
{ "Y&   
System.err.println("File Length is not known!"); '-[hy>t  
} Z~8%bfpe  
else if(nFileLength == -2) m6$&yKQ-=h  
{ DLqH*U  
System.err.println("File is not access!"); Vwh ;QJxb  
} #W3H;'~/5  
else _od /)#  
{ G e]NA]<  
for(int i=0;i<nStartPos.length;i++) )z18:C3  
{ @U1|?~M%s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r =vY-p  
} >wt.)c?5  
for(int i=0;i<nEndPos.length-1;i++) kD%MFT4  
{ y%61xA`#  
nEndPos = nStartPos[i+1]; xU0iz{9  
} ^" 54Q^SH  
nEndPos[nEndPos.length-1] = nFileLength; h$6'9rL&i  
} r^<,f[yH  
} dh [kx  
l5&5VC)  
fR'!p: ~  
//启动子线程 >3KlI  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fHEIys,{  
for(int i=0;i<nStartPos.length;i++) lX"m |W  
{ 2y!aXk\#C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^v cnDi  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0a8\{(w  
nStartPos,nEndPos,i); h-;> v.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <jF&+[*iT  
fileSplitterFetch.start(); S Z/yijf  
} izaqEz  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3HYdb|y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A%F8w'8(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,IqE<i!U  
nEndPos = " + nFileLength); !&g_hmnIF  
// fileSplitterFetch[nPos.length-1].start(); 3Wbd=^hRvq  
&y=OZ !M  
3%1wQXr0  
//等待子线程结束 A46q`l9B  
//int count = 0; hZL!%sL7  
//是否结束while循环 vo\'ycPv  
boolean breakWhile = false; :.]EM*p?GV  
b+J|yM<`  
z _\L@b  
while(!bStop) (@xC-*  
{ ?hc=w2Ci  
write_nPos(); %N ~c9B  
Utility.sleep(500); RMT9tXe*5  
breakWhile = true; hp(MKfhH  
/}>8|#U3y  
wzd(= *N  
for(int i=0;i<nStartPos.length;i++) D})/2O p   
{ #-G@p  
if(!fileSplitterFetch.bDownOver) jLI1Ed  
{ y] D\i5Xv  
breakWhile = false; &&P9T/Zks  
break; zNrn|(Y%Y  
} Q5Nbu90  
} 3!gz^[!?EN  
if(breakWhile) (:`4*xK  
break; JU^Y27  
nA(" cD[,  
qp6'n&^&  
//count++; H%U  
//if(count>4) U2<q dknB  
// siteStop(); H+Bon=$cE!  
}  =5B5  
#TR!x,Hc  
*K$a;2WjzG  
System.err.println("文件下载结束!"); hp2E! Cma  
} bF_0',W  
catch(Exception e){e.printStackTrace ();} $poIWJMc  
} *qSvSY*  
zx=eqN@!@  
F)Q[ cai  
//获得文件长度 [|eIax xR,  
public long getFileSize() XdV>6<gf{  
{ !wpK +.D  
int nFileLength = -1; mkyYs[  
try{ lV^:2I/  
URL url = new URL(siteInfoBean.getSSiteURL()); ej kUNCKQt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h;+O96V4.  
httpConnection.setRequestProperty("User-Agent","NetFox"); > TCit1yD  
dO1 m  
PDA9.b<q0  
int responseCode=httpConnection.getResponseCode(); RS}_cm0  
if(responseCode>=400) l{C]0^6>i  
{ ]oSx]R>{f  
processErrorCode(responseCode); YQ d($  
return -2; //-2 represent access is error fcF|m5  
} NJr)f  
S>(xx"Ia  
H.{Fw j4  
String sHeader; Ay qs~&{  
4C_1wk('  
5!Y\STn  
for(int i=1;;i++) Wc+(xk  
{ ,~Xe#e M  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |&WYu,QQ4  
//Utility.log(in.readLine()); h'h8Mm  
sHeader=httpConnection.getHeaderFieldKey(i); H#hpaP;  
if(sHeader!=null) Hkia&nz'3  
{ 86-Rm  
if(sHeader.equals("Content-Length")) ?r&~(<^z  
{ AU`z.Isf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); E8sM`2z5  
break; I F!xZ6X8  
} L,#YP#O,j  
} rqN+0CT  
else c)^A|{,G  
break; AhOBbss]q  
} RPeH[M^  
} v*GS>S  
catch(IOException e){e.printStackTrace ();} dZ(Z]`L,B  
catch(Exception e){e.printStackTrace ();} t6KKfb  
> _sSni  
Eb9h9sjv  
Utility.log(nFileLength); i{$P.i/&  
H9TeMY  
8i73iTg(  
return nFileLength; Z9 ws{8@_  
} CUpRtE8@[_  
Y iuV\al  
&XCd2  
//保存下载信息(文件指针位置) Jf7H;ZM<  
private void write_nPos() iN'T^+um=  
{ NkBvN\CQ  
try{ Hn)? xw]x  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^J7q,tvbJ  
output.writeInt(nStartPos.length); ['\R4H!x  
for(int i=0;i<nStartPos.length;i++) <BBzv-?D  
{ +0ukLc@  
// output.writeLong(nPos); &glh >9:G  
output.writeLong(fileSplitterFetch.nStartPos); Pz2Q]}(w  
output.writeLong(fileSplitterFetch.nEndPos); ~gZ1*8 s`  
} [olSgq!3  
output.close(); jsgDJ}  
} R#~l[S8u^  
catch(IOException e){e.printStackTrace ();} dPpQCx f  
catch(Exception e){e.printStackTrace ();} GR*sk#{  
} Z*q&^/N  
<`vXyPA6  
RY)x"\D  
//读取保存的下载信息(文件指针位置) ,|\\C6s  
private void read_nPos() `g1?Q4h  
{ yc7b%T*Y  
try{ BWYv.&=(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); m2(}$z3e  
int nCount = input.readInt(); Ucy=I$"  
nStartPos = new long[nCount]; dI7rx+L  
nEndPos = new long[nCount]; lbovwj  
for(int i=0;i<nStartPos.length;i++) r>bgCQ#-n  
{ O!dS;p-F  
nStartPos = input.readLong(); _8 K|2$X  
nEndPos = input.readLong(); }eZ \~2  
} ol_\ "  
input.close(); !WlL RkwO  
} 8lqmd1v  
catch(IOException e){e.printStackTrace ();} 6 A]a@,PC  
catch(Exception e){e.printStackTrace ();} 3*%+NQIj  
} RfvvX$  
5X];?(VTsb  
Px?"5g#+  
private void processErrorCode(int nErrorCode) u|$HA>F[  
{ A~E S{Zkh  
System.err.println("Error Code : " + nErrorCode); 8irTGA  
} f&5S`}C  
I'{Ctc  
*< fJgc"3  
//停止文件下载 p(GI02|n  
public void siteStop() CL5^>. }  
{ "-Ny f  
bStop = true; p</t##]3ks  
for(int i=0;i<nStartPos.length;i++) 8kU(>' ^_:  
fileSplitterFetch.splitterStop(); l> H'PP~  
'Tqusr>lPY  
 n9&fH  
} `]GL3cIh:  
} ti1R6oSn  
//负责部分文件的抓取 V:5aq.o!  
**FileSplitterFetch.java };9/J3]m  
*/ *tpS6{4=#7  
package NetFox; A 9l d9R  
4<1V  
1l^[%0  
import java.io.*; >{Mv+  
import java.net.*; xgNV0;g,  
#H Jlm1d  
Z&H_+u3j  
public class FileSplitterFetch extends Thread { 0;`FS /[(f  
%UooZO  
h'G  
String sURL; //File URL wt@TR~a  
long nStartPos; //File Snippet Start Position [N[4\W!!  
long nEndPos; //File Snippet End Position 0lq?l:/  
int nThreadID; //Thread's ID Bo ywgL|  
boolean bDownOver = false; //Downing is over ;QG8@ms|  
boolean bStop = false; //Stop identical 6_yatq5c  
FileAccessI fileAccessI = null; //File Access interface ~n0Exw(  
C{l-l`:  
Kt]vTn7!9  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z{#3-O<a+n  
{ `]19}GK~xo  
this.sURL = sURL; M!gu`@@}F  
this.nStartPos = nStart; 438r]f?0|{  
this.nEndPos = nEnd; DrBkR` a?  
nThreadID = id; jc>B^mqx  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9$[MM*r  
} xo ^|d3  
{s6#h#U  
}NV<k  
public void run() zU0JwZi  
{ 86qQ"=v  
while(nStartPos < nEndPos && !bStop) U m`KmM3  
{ Ik5-ooZ&{  
n2c(x\DA&  
Ha ZV7  
try{ v=dN$B5y3  
URL url = new URL(sURL); q:jv9eL.O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lQ [JA[  
httpConnection.setRequestProperty("User-Agent","NetFox"); K'"s9b8  
String sProperty = "bytes="+nStartPos+"-"; =:R${F  
httpConnection.setRequestProperty("RANGE",sProperty); dYwEVu6q  
Utility.log(sProperty); 6+s&%io4  
$j(4FyH\  
r}|)oG,=  
InputStream input = httpConnection.getInputStream(); 'f %oL/,  
//logResponseHead(httpConnection); 7uv"#mq  
Pq-@waH3  
p ~+sk1[.  
byte[] b = new byte[1024]; l% %cU"  
int nRead; Zcc7 7dRA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 67Tu8I/r  
{ MScUrW!TA  
nStartPos += fileAccessI.write(b,0,nRead); qM^y@B2MO  
//if(nThreadID == 1) Fo ,8"m  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  _ qQ  
} NFur+zwv  
Vj)"?|V  
\0qFOjVj  
Utility.log("Thread " + nThreadID + " is over!"); & }"I!  
bDownOver = true; Tn3C0  
//nPos = fileAccessI.write (b,0,nRead); 3XbFg%8YG  
} Fgh an.F  
catch(Exception e){e.printStackTrace ();} EjEXev<]  
} RdpOj >fT  
} |VM=:}s&  
`q\v~FT  
lY |]  
//打印回应的头信息 Mcd K!V  
public void logResponseHead(HttpURLConnection con)  NY[48H  
{ F[v^43-^_  
for(int i=1;;i++) r|3u]rt  
{ VWCC(YRU|$  
String header=con.getHeaderFieldKey(i); J04R,B  
if(header!=null) \naG  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6,R<8a;Wn  
Utility.log(header+" : "+con.getHeaderField(header)); >Ij# +=  
else l,b_' m@  
break; t#]VR7]  
} 8L@@UUjr  
} [R~@#I P!  
M&/e*Ta5  
hNp.%XnnZ  
public void splitterStop() IeIv k55  
{ lrMkp@ f.  
bStop = true; d;r,?/C  
} Z\)P|#L$  
yW"}%) d  
_B}QS"A  
} 6H|T )  
WCI'Kh   
PCKxo;bD  
/* fjQIuM  
**FileAccess.java % <%r  
*//文件访问(定位,写) ,fm{ krE  
package NetFox; TjctK [db@  
import java.io.*; R*vfp?x  
>4T7D My  
$T2zs$  
public class FileAccessI implements Serializable{ MB.LHIo  
MY&?*pV)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V5I xZn%  
RandomAccessFile oSavedFile; iW? NxP  
long nPos; JQ\o[t  
2 t]=-@  
@c,=c+-  
public FileAccessI() throws IOException @oMl^UYM=  
{ 5pE@Ww  
this("",0); .Ag)/Xm(?  
} Vf(n  
@d[)i,d:G  
XToYtdt2  
public FileAccessI(String sName,long nPos) throws IOException <,nd]a  
{ 7^h*rL9  
oSavedFile = new RandomAccessFile(sName,"rw"); D4+OWbf6  
this.nPos = nPos; [rhK2fr:i  
oSavedFile.seek(nPos); vRO`hGH  
} V4%7Xj  
4-xg+*()  
}GGH:v  
public synchronized int write(byte[] b,int nStart,int nLen) r*ry8QA  
{ OgyHX>}bH  
int n = -1; D_I_=0qNd  
try{ 8GT{vW9  
oSavedFile.write(b,nStart,nLen); 7I6& *I  
n = nLen; pkA(\0E8  
} B|BJkY'  
catch(IOException e) W4AFa>h  
{ G9> 0w)r  
e.printStackTrace (); DTx>^<Tk  
} O@KAh5EB  
A Rjox`  
IAbH_+7O  
return n; sVIw'W  
} a^9}ceu?   
&R}2/Mt  
/vFdhh  
} `ve5>aw0_Y  
4*+)D8  
eN I6V/\`  
/* uacVF[9|W  
**SiteInfoBean.java EF'U`\gX  
*/ p \,PY  
package NetFox; ]3yaIlpD1  
>K;C?gHo  
ljj}X JQ  
public class SiteInfoBean { :U#4H;kk~j  
pd}af iF  
 0GiL(e|  
private String sSiteURL; //Site's URL +t;j5\HS  
private String sFilePath; //Saved File's Path ?-P W$p  
private String sFileName; //Saved File's Name E.rfS$<1  
private int nSplitter; //Count of Splited Downloading File ob>2SU[Y  
&1Idv}@!  
>PiEu->P,  
public SiteInfoBean() Tk0Senq,  
{//nSplitter的缺省值为5 r}])V[V  
//default value of nSplitter is 5 X9n},}bJ"  
this("","","",5); cH\.-5NQ  
} |=4imM7  
`Jon^&^;|  
2UjQ!g`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *.NVc  
{ I)X33X,  
sSiteURL= sURL; 1C\[n(9  
sFilePath = sPath; <al/>7z' O  
sFileName = sName; 9mH/xP:y  
this.nSplitter = nSpiltter; \P0>TWE  
#+Cu&l  
,Tc598D  
} dJd(m&.|N  
Q68q76  
!XS ;&s7[*  
public String getSSiteURL() go$zi5{h#  
{ SdBo sB3v>  
return sSiteURL; AE 2>smp5@  
} a-7T   
JN-wToOF  
IHtNaN )  
public void setSSiteURL(String value) ( RCQbI  
{ Qf}b3WEAI  
sSiteURL = value; ^iaG>rvA  
} qY$/i#  
G4eY}3F7,4  
$ @cg+Xrg1  
public String getSFilePath() rXlJW]i  
{ BliL1"".  
return sFilePath; ril4*$e7^\  
} Y-Gqx  
\sZ!F&a~  
E)w^odwMU  
public void setSFilePath(String value) H"A|Z6y$^  
{ VdV18-ea  
sFilePath = value; ZkZTCb`/l  
} 48 `k"Uy   
6{p] cr  
c31k%/.  
public String getSFileName() m#a0HH  
{ }?jL;CCe  
return sFileName; @NS=  
} kG>d^K  
^ LT KX`p  
\-B8`ah  
public void setSFileName(String value)  Lx:O Dd  
{ 4 u!)QG  
sFileName = value; c~a:i=y67  
} !yQ#E2/A  
A\7qPfpG  
MjW g  
public int getNSplitter() 8QN#PaY  
{ =)GhrWeVi4  
return nSplitter; i?&g;_n^  
} H#l uG_)  
+84JvOkWi  
Hki  
public void setNSplitter(int nCount) s<t*g]0`/  
{ P=%' 2BQ{{  
nSplitter = nCount; b+.P4+  
} tz&oe  
} S0 AaJty  
uIkB&  
2}P?N  
/* L`Lro:E?kL  
**Utility.java OTNcNY  
*/ 1 \_S1ZS  
package NetFox; 5P'<X p  
;LM,<QJ  
IOx9".  
public class Utility { W9ZfD~(3-  
CVp`G"W:  
8MH ZWi  
public Utility() K(+ ~#$|-~  
{ kCO`JAH#  
!vB8Pk"  
n .{Ud\|  
} mBC?Pg  
  SW ^F  
//线程睡眠 G G]4g)O5  
public static void sleep(int nSecond) k/&~8l.$  
{ 0T{Z'3^=  
try{ Vnu*+  
Thread.sleep(nSecond); #3l&N4/  
} j~d<n_   
catch(Exception e) jU~ ! *]  
{ y3 vDKZ  
e.printStackTrace (); +O 2H":$  
} _<`j?$P  
} t7"vAjZU  
Uk=-A @q  
//日志 f,'gQ5\ X3  
public static void log(String sMsg) brk>oM;t  
{ 1Z5:D E<  
System.err.println(sMsg); 2nL [P#r  
} FaOfe]F  
|]tIE{d  
FOAy'76p  
public static void log(int sMsg) VfK8')IXk  
{ DeTx7i0  
System.err.println(sMsg); biy1!r  
} $n30[P@p;  
} 3_:J`xX(4  
D\}A{I92F4  
TmZ% ;TN  
/* {_GhS%  
**TestMethod.java UQmdm$.  
*/ bT^6AtsJ  
package NetFox; =.Tc l"O[  
%jgB;Y  
}0& @J'<  
public class TestMethod { 5.KhI<[  
umt*;U=  
2WK]I1_  
public TestMethod() i$GL]0  
{ ///xx/weblogic60b2_win.exe 8ug\GlZc  
try{ E>t5/^c)*w  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); HAof,* h$  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \>b :  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _sEkKh8x  
fileFetch.start(); >l & N  
} JVPl\I  
catch(Exception e){e.printStackTrace ();} u|v2J/_5Y  
,i>{yrsOh  
@+OX1-dd/w  
} noali96J  
B:-qUuS?R  
#nTzn2  
public static void main(String[] args) ;<j[0~qp:  
{ ?Vy% <f$  
new TestMethod(); lV4|(NQ9  
} vkFq/+'U  
} eI%{/>  
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