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http断点续传简单实现(java)

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/* YnU*MC}  
**SiteFileFetch.java ~Hd *Xl  
*/ g/FT6+&T.  
package NetFox; Kc@Sw{JR#7  
import java.io.*; ~-G_c=E?  
import java.net.*; +2p}KpOsL  
eVX/<9>  
F_ -Xx"  
public class SiteFileFetch extends Thread { dEI!r1~n  
[_ uT+q3  
GbQg(%2F  
SiteInfoBean siteInfoBean = null; //文件信息Bean hAds15 %C  
long[] nStartPos; //开始位置 cM,g, E}  
long[] nEndPos; //结束位置  `2\:b^h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4M0p:Ey '  
long nFileLength; //文件长度 RkTYvAk|kY  
boolean bFirst = true; //是否第一次取文件 '"c`[L7Wn  
boolean bStop = false; //停止标志 x <aR|r  
File tmpFile; //文件下载的临时信息 _V8;dv8  
DataOutputStream output; //输出到文件的输出流 eNH9`Aa  
#}Xsi&:XU  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Q t>|TGz  
public SiteFileFetch(SiteInfoBean bean) throws IOException uK#2vgT  
{ u] G  
siteInfoBean = bean; )p#L"r^)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wi%ls8F  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); XL;WU8>  
if(tmpFile.exists ()) !,Cbb }  
{ " o 3Hd  
bFirst = false; A42!%>PB  
read_nPos(); ']sj W'~  
} y,OG9iD:h  
else VMo:pV  
{  > T:0  
nStartPos = new long[bean.getNSplitter()]; 1A* "v  
nEndPos = new long[bean.getNSplitter()]; b5.]}>]t  
} ={]POL\ A  
~e)"!r  
Y]`o-dV  
tnBCO%uG  
} Yne1MBK  
~gQYgv<7  
VV 54$a  
public void run() 9pr.`w  
{ f)Y~F/[$P  
//获得文件长度 :AQ9-&i/a-  
//分割文件 3 _!MVT  
//实例FileSplitterFetch #Jp|Cb<qx  
//启动FileSplitterFetch线程 n{{"+;oR  
//等待子线程返回 r XBC M  
try{ JrX. f  
if(bFirst) ZzQLbCV  
{ Nq6; z)$  
nFileLength = getFileSize(); !&.-{ _$  
if(nFileLength == -1) i6P$>8jBQ-  
{ 3xdJ<Lrq  
System.err.println("File Length is not known!"); Q W c^}#!!  
} $-jj%kS  
else if(nFileLength == -2) \hEIQjfi  
{ qu'D"0  
System.err.println("File is not access!"); bI(8Um6m  
} XWNo)#_3  
else 2AMb-&po&f  
{ k!bJ&} Q(b  
for(int i=0;i<nStartPos.length;i++) 35x]'  
{  n0EW U,1  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1_;{1O+B  
} *(5T?p[7  
for(int i=0;i<nEndPos.length-1;i++) D#`>p  
{ C9""sVs  
nEndPos = nStartPos[i+1]; v046  
} -0]%#(E%`h  
nEndPos[nEndPos.length-1] = nFileLength; ?1O` Rd{tn  
} 62Tel4u  
} xpu 2RE  
f<|*^+  
jY=M{?h''  
//启动子线程 ~J5B?@2hK  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; C(z 'oi:f  
for(int i=0;i<nStartPos.length;i++) ?<\2}1  
{ Nz*,m'-1e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -II03 S1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), l[%=S!  
nStartPos,nEndPos,i); Lp4F1H2t-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); lOe|]pQ.,  
fileSplitterFetch.start(); P*U^,Jh<  
} nqTOAL9FF  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;i/? fw[h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ZSD7%gE<D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", o Q*LP{M  
nEndPos = " + nFileLength); a0PU&o1EF  
// fileSplitterFetch[nPos.length-1].start(); \[)SK`cwd  
V eY&pPQ  
l]Ym)QP  
//等待子线程结束 !h<O c!9  
//int count = 0; }s6Veosl  
//是否结束while循环 CBpwtI>p  
boolean breakWhile = false; G+k wG)K  
>LH}A6dUC  
&RI;!qn6(  
while(!bStop) R9"}-A  
{ ]$s b<o .a  
write_nPos(); 23,pVo  
Utility.sleep(500); J6>tGKa+e  
breakWhile = true; _%\%  
kd]CV7(7  
yx*<c#Uf  
for(int i=0;i<nStartPos.length;i++) bGy|T*@  
{ @t*D<B$  
if(!fileSplitterFetch.bDownOver) ukc 7Z OQ  
{ Tow!5VAM  
breakWhile = false; ~_F;>N~  
break; T (]*jaB  
} 0*oavY*  
} l%?4L/J)#  
if(breakWhile)  ylS6D  
break; guf*>qNr  
)^"V}z t  
Dfc% jWbA  
//count++; 2+C:Em0yI  
//if(count>4) ;4GGXT++L  
// siteStop(); f4F%\ "  
} 19pFNg'kA  
.5s^a.e'O  
3c(mZ   
System.err.println("文件下载结束!"); qK2jJ3)>  
} Hi/[  
catch(Exception e){e.printStackTrace ();} V\e1NS  
} 0S'@(p[A  
~Cg7  
PX2b(fR8_O  
//获得文件长度 ;O{bF8 U  
public long getFileSize() h+Yd \k  
{ `_i|\}tl  
int nFileLength = -1; 5ug|crX  
try{ j(K)CHH  
URL url = new URL(siteInfoBean.getSSiteURL()); FU J<gqL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rwio>4=  
httpConnection.setRequestProperty("User-Agent","NetFox"); $/@  L  
ZJF+./vN  
`g)  
int responseCode=httpConnection.getResponseCode(); Tr|PR t  
if(responseCode>=400) HVhd#Q;  
{ UugR  
processErrorCode(responseCode); K=}Eupn=  
return -2; //-2 represent access is error q bCU&G|)  
} f1elzANy  
:PY6J}:&#  
7zA+UWr  
String sHeader; [u^ fy<jdp  
{.[EXMX  
J|^z>gP(  
for(int i=1;;i++) mh`uvqY  
{ ur=:Ha  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); zxH<~2  
//Utility.log(in.readLine()); 0 z]H=  
sHeader=httpConnection.getHeaderFieldKey(i); J P5en  
if(sHeader!=null) UIg?3J}R  
{ C]l)Pz$  
if(sHeader.equals("Content-Length")) bmi",UZ:F  
{ yHlQKI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 11Qi _T\  
break; aJF/y3  
} ~ qaT jSP  
} *tk=DsRW  
else ;*9<lUvu  
break; >j$aY  
} i_*.  
} p5w9X+G%  
catch(IOException e){e.printStackTrace ();} #Ufb  
catch(Exception e){e.printStackTrace ();} 1[#sHj$Na`  
J=(i0A  
Bgzq  
Utility.log(nFileLength); uudd'L  
J7%rPJ  
5} ur,0{  
return nFileLength; <sM_zoprc  
} U>bIQk"4  
.a(G=fk  
}$qrNbLJ  
//保存下载信息(文件指针位置) skTa IGRL  
private void write_nPos() r$'.$k\  
{ *O@Zn  
try{ !b4AeiL>w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Qp)?wny4  
output.writeInt(nStartPos.length); |`Yn'Mj8rm  
for(int i=0;i<nStartPos.length;i++) tX@y ]"  
{ _T~&kwe  
// output.writeLong(nPos); VAUd^6Xdwx  
output.writeLong(fileSplitterFetch.nStartPos); I>vU;xV\m  
output.writeLong(fileSplitterFetch.nEndPos); ggkz fg&  
} u^c/1H:6  
output.close(); X eY[;}9  
} { D|ST2:E  
catch(IOException e){e.printStackTrace ();} X&5N 89  
catch(Exception e){e.printStackTrace ();} Q=vo5)t   
} br 3-.g  
ycki0&n3  
,`!lZ| U  
//读取保存的下载信息(文件指针位置) 02tN=}Cj)  
private void read_nPos() -aE,KQ  
{ F9r/ M"5  
try{ F$|:'#KN  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;mz#$"(  
int nCount = input.readInt(); F2_'U' a  
nStartPos = new long[nCount]; h8Oj E$ H  
nEndPos = new long[nCount]; J(maJuY  
for(int i=0;i<nStartPos.length;i++) y;4g>ma0  
{ 3 Fy C D4#  
nStartPos = input.readLong(); H.C*IL9  
nEndPos = input.readLong(); +Zr~mwM=x  
} 4KSq]S.  
input.close(); :[f[-F  
} +~o f#  
catch(IOException e){e.printStackTrace ();} !+z^VcV  
catch(Exception e){e.printStackTrace ();} #Cy3x-!  
} )+8r$ i  
#Dz"g_d  
p1i}fGS  
private void processErrorCode(int nErrorCode)  cC|  
{ V*(x@pF  
System.err.println("Error Code : " + nErrorCode); ahCwA}  
} fk X86  
iS<1C`%>  
UWS 91GN@  
//停止文件下载 m-;8O /  
public void siteStop() >=:mtcph  
{ M6qNh`+HO  
bStop = true; F1B/cd  
for(int i=0;i<nStartPos.length;i++) Q*1'k%7  
fileSplitterFetch.splitterStop(); *icaKy3  
q _K@KB  
QJiH^KY6  
} x5pu+-h  
} F$1{w"&  
//负责部分文件的抓取 a_{'I6a*,  
**FileSplitterFetch.java C!+PBk[9  
*/ tX1`/}``  
package NetFox; )\2KDXc  
/38I (0  
77aUuP7Iw  
import java.io.*; f? GoBh<  
import java.net.*; $ve$Sq  
i[FYR;C  
tSoF!@6  
public class FileSplitterFetch extends Thread { y:$qX*+9e  
9,\AAISi  
q+<,FdG  
String sURL; //File URL $?gKIv>g  
long nStartPos; //File Snippet Start Position r2i]9>w  
long nEndPos; //File Snippet End Position /YJBRU2  
int nThreadID; //Thread's ID J&JZYuuf  
boolean bDownOver = false; //Downing is over @W @,8e]c  
boolean bStop = false; //Stop identical zw$\d1-+h  
FileAccessI fileAccessI = null; //File Access interface mJ5%+.V  
Iw( wT_  
Knb(MI6  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException b2[U3)|oO  
{ OkISR j'!U  
this.sURL = sURL; yI07E "9  
this.nStartPos = nStart; Fn4yx~0  
this.nEndPos = nEnd; O:T 49:R}r  
nThreadID = id; |*h{GX.(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |]?W`KN0  
} 8f)pf$v`   
fi~@J`  
)t7MD(  
public void run() GVn'p Wg  
{ 7 <]YK`a2d  
while(nStartPos < nEndPos && !bStop) n6Uf>5  
{  < ]+Mdy  
wmXI8'~F&  
z-g6d(  
try{ ;1nXJ{jKw  
URL url = new URL(sURL); gN[t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~!7x45( 1#  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]>k8v6*=  
String sProperty = "bytes="+nStartPos+"-"; ;/?w-)n?  
httpConnection.setRequestProperty("RANGE",sProperty); t>*(v#WeZ  
Utility.log(sProperty); 3W#E$^G_v  
!^0vi3I  
nec}grA  
InputStream input = httpConnection.getInputStream(); Z0y~%[1X  
//logResponseHead(httpConnection); g=qaq  
/iQh'rp  
0CXXCa7!  
byte[] b = new byte[1024]; `r3 klL,W'  
int nRead; bXXX-Xc  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  QV\a f  
{ 6o9&FU  
nStartPos += fileAccessI.write(b,0,nRead); /z`tI  
//if(nThreadID == 1) \{~CO{II  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dvZlkMm   
} k2,`W2] ^E  
eK*oV}U-k  
K4]ZVMm/*  
Utility.log("Thread " + nThreadID + " is over!"); 5|Z8UzL  
bDownOver = true; F!/-2u5gF  
//nPos = fileAccessI.write (b,0,nRead); O#O"]A  
} $ #GuV'  
catch(Exception e){e.printStackTrace ();} yuJ>xsM  
} /0fsn_  
} ;E.f%   
n$7*L9)(C  
NW3qs`$-(  
//打印回应的头信息 )flm3G2u  
public void logResponseHead(HttpURLConnection con) fB,eeT1v?h  
{ $ywROa]  
for(int i=1;;i++) 9b,0_IMHH  
{ 8tna<Hx  
String header=con.getHeaderFieldKey(i); /7p(%vr  
if(header!=null) 41+WIa L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); l`:u5\ rM  
Utility.log(header+" : "+con.getHeaderField(header)); 1ZYo-a;)  
else T:2f*!r  
break; 3k(tv U+eC  
} ?K2}<H-  
} cTRtMk%^  
QUvSeNSp  
g"Ueo'd*  
public void splitterStop() c$BH`" <*  
{ t?Q bi)T=z  
bStop = true; BtKor6ba  
} Hy,""Py  
h7TkMt[l  
+Ig%h[1a  
} *fv BB9raq  
Fo;:GX,b  
,RY;dX-#  
/* c|aX4=Z  
**FileAccess.java W(4$.uZ)  
*//文件访问(定位,写) g.%} +5  
package NetFox; CQa8I2VF (  
import java.io.*; cjO %X  
.sM,U  
bqA`oRb\  
public class FileAccessI implements Serializable{ -Eq[J k  
`#8kJt  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 l Ib d9F  
RandomAccessFile oSavedFile; `^'fS@VA  
long nPos; *jPd=+d  
In1n.oRFn^  
)s, t BU+N  
public FileAccessI() throws IOException ST?Rl@4  
{ 2cIKph  
this("",0); 5k Q@]n:<k  
} yqL"YD  
kTI5CoXzq  
Q 3^h  
public FileAccessI(String sName,long nPos) throws IOException S^p^) fAmF  
{ $@] xi  
oSavedFile = new RandomAccessFile(sName,"rw"); ZnzO]  
this.nPos = nPos; FkuD Gg~a  
oSavedFile.seek(nPos); >qr/1mW  
} [{GN#W|AGP  
='4)E6ea?  
qz3 Z'  
public synchronized int write(byte[] b,int nStart,int nLen) chKEGosbF  
{ |K{ d5\_  
int n = -1; c?. i;4yh  
try{ w%X@os}E  
oSavedFile.write(b,nStart,nLen); ]$9y7Bhj.  
n = nLen; (S+/e5c)  
} JR15y3 F  
catch(IOException e) -@`Ah|m@}  
{ HQ7g0:-^a>  
e.printStackTrace (); |mHf 7gCX  
} oD\t4]?E  
yTK3eK  
cqJXZ.X C  
return n; Aaq%'07ihW  
} I=<Qpd4  
i '*!c  
n^hkH1vY  
} >1Hv c7DP  
 8 zlvzp  
2\z|/ Q  
/* dW!El^w}  
**SiteInfoBean.java "M[&4'OM  
*/ zp}pS2DU  
package NetFox; ]adgOlM  
ry=8Oq&[~  
L*,h=#x(  
public class SiteInfoBean { H&p:  
Qox/abC h  
A s}L=2  
private String sSiteURL; //Site's URL dhnX\/  
private String sFilePath; //Saved File's Path !y/e Fx  
private String sFileName; //Saved File's Name vazA@|^8  
private int nSplitter; //Count of Splited Downloading File Y`eF9Im,  
"!AtS  
=SeQ- H#  
public SiteInfoBean() !o?&{"#+  
{//nSplitter的缺省值为5 jIrfJ*z  
//default value of nSplitter is 5 $':5uU1}  
this("","","",5); T|D^kL%m!  
} jN*wbqL  
{J,"iJKop  
^0}wmxDq  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) js Z"T  
{ RN[x\",  
sSiteURL= sURL; lMu-,Z="  
sFilePath = sPath; 5Ww,vSCV)  
sFileName = sName; M/9[P* VE  
this.nSplitter = nSpiltter; \< T7EV.  
H? Q--pG8  
hE`d@  
} !z4I-a  
sZr \mQ~  
}[UH1+`L  
public String getSSiteURL() pL;e(lM  
{ 7.ein:M|CB  
return sSiteURL; V59!}kel1%  
} Db*b"/]  
Y,}h{*9Kd  
cNmAr8^}  
public void setSSiteURL(String value) R13k2jLSQ  
{ JeNX5bXW  
sSiteURL = value; % 33O)<?  
} pt3)yj&XE  
DeNWh2  
Fv %@k{  
public String getSFilePath() ?6&G:Uz/  
{ U>.5vK.+  
return sFilePath; p!=8Pq.  
} [hg9 0Q6  
Kg>B$fBx)  
YlG#sBzl  
public void setSFilePath(String value) L xIKH G  
{ F02TM#Zi  
sFilePath = value; O|=?!|`o  
} @d|Sv1d%  
cQThpgha  
O{\<Izm`D  
public String getSFileName() VBDb K|  
{ <D)@;A  
return sFileName; o&@y^<UQ  
} <bg6k .s  
XP}5i!}}7=  
2 YWO'PL  
public void setSFileName(String value) qM26:kB{  
{ Pp69|lxV=k  
sFileName = value; .*oL@iX  
} 1D8S}=5&  
CPcUB4a%#  
%@)q=*=y  
public int getNSplitter() ONcLhwH  
{ *?uUP  
return nSplitter; ;'V[8`Z@  
} i>CR{q  
Ti0kfjhX7  
!.O[@A\.-  
public void setNSplitter(int nCount) K,|3?CjS  
{ GIpYx`mHi  
nSplitter = nCount; y&8`NS#_p?  
} -@#],s7  
} <kwF<J  
t5K#nRd Z:  
_:tS-Mx@5  
/* A&v Qtd  
**Utility.java 9IG<9uj  
*/ (0LA.aBIf  
package NetFox; h@ ZC{B  
#Y-_kQV*  
*)^ ZUk  
public class Utility { d$+0 ;D4E  
dJ])`S  
i(.PkYkaq  
public Utility() Ev [?5R  
{ <im}R9eJ1  
#>lbpw  
( )ldn?v  
} l,b,U/3R.  
,H/O"%OJ  
//线程睡眠 rOEBL|P0  
public static void sleep(int nSecond) :KG=3un]  
{ tCR~z1  
try{ m3P7*S5NJ7  
Thread.sleep(nSecond); ,f,+)C$  
} b.[9Adi >  
catch(Exception e) }.9a!/@Aj  
{ hH;i_("i(h  
e.printStackTrace (); zI S ,N '  
} xnWezO_  
} MwSfuP  
0~W XA=XG  
//日志 Bv3B|D&+  
public static void log(String sMsg) `H*mQERb  
{ +=|%9%  
System.err.println(sMsg); 09Eg ti.  
} lcReRcjm  
]=xX_  
&vN!>bR  
public static void log(int sMsg) 2Y[n  
{ E U RKzJk  
System.err.println(sMsg); -p7 HQ/  
} 3&M0@/  
} oPbziB8  
w7pX]<?R"  
edlf++r~  
/* J n2QvUAZ&  
**TestMethod.java \' A- Lp  
*/ j%]sym  
package NetFox; R!X+-  
gC kR$.-E  
ZDI?"dt{  
public class TestMethod { O6b+eS  
?LU>2!jN  
V7gL*,3>=  
public TestMethod() eUR+j?5I  
{ ///xx/weblogic60b2_win.exe N;!!*3a9=  
try{ 8$iHd  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |{ZdAr.;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); bi@'m?XwJ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -T+'3</T  
fileFetch.start(); Nqd9)WQ  
} +`B^D  
catch(Exception e){e.printStackTrace ();} !a!4^zqp  
*u,&?fCl  
I7Abf7>*Q  
} 5t_Dt<lIz  
6iEg]FI  
@/$i -?E  
public static void main(String[] args) y[S9b (:+  
{ yqtHlz%  
new TestMethod(); unz~vG1Tn  
} .V_5q:tu  
} Z:x`][vg  
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