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http断点续传简单实现(java)

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/*  Ok[y3S  
**SiteFileFetch.java ,#rl"  
*/ w~QUG^0Fx  
package NetFox; Qfr%BQV  
import java.io.*; >l{<p(  
import java.net.*; g![]R-$  
&bBK#d*-u?  
'WkDp a  
public class SiteFileFetch extends Thread { l~Je ]Qt  
LJDX6]4n  
#\*ODMk$4|  
SiteInfoBean siteInfoBean = null; //文件信息Bean qlmz@kTb  
long[] nStartPos; //开始位置 fQc2K|V  
long[] nEndPos; //结束位置 T;X8T  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $A,fO~  
long nFileLength; //文件长度 W+V#z8K  
boolean bFirst = true; //是否第一次取文件 {X<mr~  
boolean bStop = false; //停止标志 <@ D`16%&  
File tmpFile; //文件下载的临时信息 O79;tA<k  
DataOutputStream output; //输出到文件的输出流 ww82)m8  
{C Qo}@.7  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ~` v 7  
public SiteFileFetch(SiteInfoBean bean) throws IOException O= PFr"  
{ c)gG  
siteInfoBean = bean; LS@[O])$'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ps5UX6\ .m  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); zd AqGQfc  
if(tmpFile.exists ()) |^Nz/PN  
{ V`?2g_4N  
bFirst = false; FCTz>N^p  
read_nPos(); xcr=AhqM  
} (-Rh%ZHH  
else rXXIpQRi$S  
{ X9C)FS  
nStartPos = new long[bean.getNSplitter()]; @=q,,t$r  
nEndPos = new long[bean.getNSplitter()]; 3 G/#OJ  
} XH&Fn+  
=A&x d"  
jca7Cx`sm  
" ,&#9  
} L+2!Sc,>  
B8-v!4b0`  
9.ZhkvR4A  
public void run() 2P`QS@v0a=  
{ g9(zJ  
//获得文件长度 itb0dF1G  
//分割文件 ;mH1J'.(a  
//实例FileSplitterFetch aZ^P*|_K3  
//启动FileSplitterFetch线程 TtEc~m  
//等待子线程返回 'bp*hqG[  
try{ ?F'gh4  
if(bFirst) g{w IdV  
{ Qx CZ<|  
nFileLength = getFileSize(); l4u@0;6P  
if(nFileLength == -1) c\~H_ ~F  
{ T677d.zaT  
System.err.println("File Length is not known!"); R< @o]p  
} 6J0HaL  
else if(nFileLength == -2) 6He7A@Eh  
{ ^Cb7R/R3  
System.err.println("File is not access!"); QA7SQ cd,  
} f2Frb  
else E< nXkqD  
{ JG&`l{c9  
for(int i=0;i<nStartPos.length;i++) Kd^{~Wlz&z  
{ H6?ZE  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Bmuf[-}QW  
} JPL8fX-w  
for(int i=0;i<nEndPos.length-1;i++) p%e! &:!  
{ ?6.vd]oNO  
nEndPos = nStartPos[i+1]; jq(3y|6,  
} 1BQTvUAA  
nEndPos[nEndPos.length-1] = nFileLength; k+S+ : 5  
} $@d`Kz;  
} m)9N9Ii#)  
GXB4&Q!C  
_.0c~\VA  
//启动子线程 Y W_E,A>h  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; K;;Q*NN-  
for(int i=0;i<nStartPos.length;i++) `HU`=a&d  
{ fVv#|   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Frn#?n)S9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ):?ype>  
nStartPos,nEndPos,i); vc o/h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  =Run  
fileSplitterFetch.start(); =MO2M~e!  
} LB%_FT5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), awuUaE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a%f{mP$m  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {LTb-CB  
nEndPos = " + nFileLength); Us.yKAHPV  
// fileSplitterFetch[nPos.length-1].start(); :Bp{yUgi@  
D4'"GaCv  
>U~.I2sz  
//等待子线程结束 Z:aDKAboU  
//int count = 0; e3YZ-w^W~h  
//是否结束while循环 I2("p.+R  
boolean breakWhile = false; b6_*ljM  
f|Kd{ $VO  
lqA U5K{wQ  
while(!bStop) >bxT_qEm  
{ 8h9t8?  
write_nPos(); * JGm  
Utility.sleep(500); *2crhI*@>  
breakWhile = true; VBR@f<2L  
L5%~H?K(  
)/2* <jr  
for(int i=0;i<nStartPos.length;i++) %*OKhrM  
{ ? Ldw\  
if(!fileSplitterFetch.bDownOver) !;lA+O-t  
{ &w:"e'FG`  
breakWhile = false; _6THyj$f  
break; cRz7.9-<  
} X obiF  
} 7M}T^LC  
if(breakWhile) i:OD)l  
break; hbR;zV|US  
e.G&hJ r  
s2g}IZfo  
//count++; ^mFuZ~g;?  
//if(count>4) UY j  
// siteStop(); iKV;>gF,)v  
} $;7?w-.  
T2Cdw\  
O<S*bN>BF  
System.err.println("文件下载结束!"); eJE?H]  
} /7|u2!#Ui  
catch(Exception e){e.printStackTrace ();} BMU~1[r  
} nlH H}K  
@z$V(}(O^  
n?&G>`u*  
//获得文件长度 1W8[ RET  
public long getFileSize() hnL"f[p@gC  
{ ujB:G0'r  
int nFileLength = -1; xBG&ZM4"^f  
try{ W5$jIQ}Bw  
URL url = new URL(siteInfoBean.getSSiteURL()); M]jzbJ3Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ko im@B  
httpConnection.setRequestProperty("User-Agent","NetFox"); s7O?)f f  
Slq=;TDp  
5'\/gvxIC  
int responseCode=httpConnection.getResponseCode(); O-wR48Q  
if(responseCode>=400) /+2^xEIjE  
{ =w".B[r  
processErrorCode(responseCode); E8jdQS|i  
return -2; //-2 represent access is error zdyS"H}  
} "<3PyW?zt  
-}2q-  
g-oHu8   
String sHeader; P`[6IS#\S  
; z:}OD  
3RscuD&  
for(int i=1;;i++) 0Z2![n  
{ A[XEbfDO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Il'+^u_ <  
//Utility.log(in.readLine()); $"J+3mO  
sHeader=httpConnection.getHeaderFieldKey(i); y M , hF  
if(sHeader!=null) ],>Z' W  
{ oQ8W0`bZa  
if(sHeader.equals("Content-Length")) ..'^1IOA  
{ n0@e%=H)I  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); nE Qw6q~je  
break; }_3<Q\j  
} GpN tvo~  
} LEc%BQx  
else 65=i`!f  
break; p[hA?dXn  
} 1`5d~>fV  
} h<6@&yzp  
catch(IOException e){e.printStackTrace ();} E$4\Yc)(AL  
catch(Exception e){e.printStackTrace ();} 50l=B]M  
fph*|T&R  
@4T+0&OI10  
Utility.log(nFileLength); $}aLFb  
zYYc#N/  
puL1A?Y8UM  
return nFileLength; x76<u:  
} i~ n>dc YW  
<{9E.6G`n  
p/cVQ  
//保存下载信息(文件指针位置) QlSZr[^v  
private void write_nPos() ] 5YG*sD4  
{ /(E)|*~6  
try{ 7zgU>$i  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Pd%o6~_*  
output.writeInt(nStartPos.length); B<H5WI  
for(int i=0;i<nStartPos.length;i++) hCc_+/j|  
{ /"~CWNa  
// output.writeLong(nPos); ts{Tk5+  
output.writeLong(fileSplitterFetch.nStartPos); ,N< xyx.  
output.writeLong(fileSplitterFetch.nEndPos); i 0L)hkV  
} 31  QT  
output.close(); 1$q SbQ  
} ] GJIrtS4  
catch(IOException e){e.printStackTrace ();} S)n ~^q  
catch(Exception e){e.printStackTrace ();} ^$6EO) <  
} pI( OI>~3  
Xi6XV3G  
wX<)Fj'  
//读取保存的下载信息(文件指针位置) p3\F1](Z  
private void read_nPos() =sG  C  
{ :jT1=PfL  
try{ 3EI$tP@4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ih{(d O;  
int nCount = input.readInt(); 3(}W=oI  
nStartPos = new long[nCount]; J3oH^  
nEndPos = new long[nCount]; 3*/y<Z'H  
for(int i=0;i<nStartPos.length;i++) @@# ^G8+l  
{ |/Ggsfmby  
nStartPos = input.readLong(); "/S-+Ufn  
nEndPos = input.readLong(); 2x"&8Bg3  
} dTB^6 >H  
input.close(); G9 ;X=c  
} O< v0{z09*  
catch(IOException e){e.printStackTrace ();} ry*b"SO  
catch(Exception e){e.printStackTrace ();} (ye1t96  
} Y#=0C*FS  
O8w R#(/  
N41)?-7F  
private void processErrorCode(int nErrorCode) ]L"jt8E  
{ N8@Fj!Zi  
System.err.println("Error Code : " + nErrorCode); X"z^4?Aj+  
} Q=)$  
MXh0a@*]  
`%ZM(9T  
//停止文件下载 D. fP Hq  
public void siteStop() pi*cO  
{ _rdEur C6  
bStop = true; I% ivY  
for(int i=0;i<nStartPos.length;i++) \xlelsmB*  
fileSplitterFetch.splitterStop(); g=0`^APql  
)>QpR8 G-  
}R=n!Y$F  
} v,I4ozDx  
} H9?(5  
//负责部分文件的抓取 _D1Uc|  
**FileSplitterFetch.java UMILAoR  
*/ &G\Vn,1v  
package NetFox; 0Dv r:]R  
}^ +E S^~  
F0t-b%w,  
import java.io.*; 5Tag-+  
import java.net.*; -GJ~xcf0  
}`ox;Q  
`|)V]<  
public class FileSplitterFetch extends Thread { [3lAKI  
 Sg  
4 3V {q  
String sURL; //File URL |J-Osi  
long nStartPos; //File Snippet Start Position F$.h+v   
long nEndPos; //File Snippet End Position NX%"_W/W  
int nThreadID; //Thread's ID _JNSl2  
boolean bDownOver = false; //Downing is over 8JYU1E w  
boolean bStop = false; //Stop identical 6|:K1bI)  
FileAccessI fileAccessI = null; //File Access interface o9\J vJk  
UR?biq  
hGh91c;4  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]dIcW9a  
{ Nk?eVJ)  
this.sURL = sURL; S9RH&/^H  
this.nStartPos = nStart; !xcLJ5^W  
this.nEndPos = nEnd; "`g5iUHqUl  
nThreadID = id; ^%ZbjJ7|j  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 AK$&'t+$}7  
} Yw=7(}  
A\ARjSdb  
 B0 E`C  
public void run() .JCd:'-  
{ _Ns/#Xe/  
while(nStartPos < nEndPos && !bStop) 9UDanj P  
{ ,/2&HZd  
W%@r   
Z<D8{&AjS  
try{ tE'^O< K  
URL url = new URL(sURL); O]_a$U*6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OFe-e(c1  
httpConnection.setRequestProperty("User-Agent","NetFox"); XM1; >#kz  
String sProperty = "bytes="+nStartPos+"-"; \MqOHM.[  
httpConnection.setRequestProperty("RANGE",sProperty); y'L7o V?L9  
Utility.log(sProperty); QNbV=*F?  
cY mgJBG  
w1Txz4JqB  
InputStream input = httpConnection.getInputStream(); 6 &Lr/J76  
//logResponseHead(httpConnection); !,lk>j.V  
0:I[;Q t  
"w&IO}j;=  
byte[] b = new byte[1024]; d! {]CZ"@  
int nRead; CKI.\o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~Uw;6VXV1  
{ t =V| '  
nStartPos += fileAccessI.write(b,0,nRead); HK NT. a  
//if(nThreadID == 1) bog3=Ig-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j+9;Rvt2  
} wKU9I[]  
w**~k]In  
p0rmcP1Ln  
Utility.log("Thread " + nThreadID + " is over!"); j)ME%17  
bDownOver = true; }1 ,\ *)5  
//nPos = fileAccessI.write (b,0,nRead); n&l(aRoyx  
} sZx`u+  
catch(Exception e){e.printStackTrace ();} Gg e X  
} Ptm=c6H('  
} t!-\:8n  
iC{(vL0P+  
5Q;Q  
//打印回应的头信息 2##;[  
public void logResponseHead(HttpURLConnection con) %2wr%*h  
{ W_L*S4 ~  
for(int i=1;;i++) 9>ajhFyOhX  
{ e%s1D  
String header=con.getHeaderFieldKey(i); )SZzA'  
if(header!=null) 8WE@ X)e  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r]@T9\9  
Utility.log(header+" : "+con.getHeaderField(header)); $Qz<:?D  
else -Ew>3Q  
break; Z`_x|cU?J  
} wBDHhXi0  
} $DXO7;#  
E{0e5.{  
qV9}N-sS  
public void splitterStop() Pbd[gKX_  
{ 3! #|hI>f  
bStop = true; yAAV,?:o[  
} r?itd)WC<X  
jzJQ/ZFS  
Zs(BViTb|  
} Nw9@E R  
3?K+wg s  
_&~l,%)&  
/* 0BNH~,0u  
**FileAccess.java tm/=Oc1p  
*//文件访问(定位,写) F?$Vx)HI  
package NetFox; Fv7]1EO.  
import java.io.*; k-H6c  
fF(AvMsO  
[O<F`u"a  
public class FileAccessI implements Serializable{ )!kt9lK  
fP:]s@$  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o{>4PZ}=g  
RandomAccessFile oSavedFile; whYk"N  
long nPos; A@Q6}ESD  
 LtH j  
"b402"&  
public FileAccessI() throws IOException Auc&dpW  
{ l9C `:g  
this("",0); :-O$rm  
} KTt+}-vP^  
Oe x   
J90:c@O"w  
public FileAccessI(String sName,long nPos) throws IOException k;jl3GV  
{ 2Y%7.YX"  
oSavedFile = new RandomAccessFile(sName,"rw"); sZ~03QvkT  
this.nPos = nPos; *+zFsu4l  
oSavedFile.seek(nPos); c]Gs{V]\  
} %19~9Tw  
!yT=*Cj4  
I{0cnq/  
public synchronized int write(byte[] b,int nStart,int nLen) tvf5b8(Y-  
{ ? A;RTM  
int n = -1; X $V_  
try{ `k>C%6FG$#  
oSavedFile.write(b,nStart,nLen); @54$IhhT~  
n = nLen; )5n0P Zi  
} 8G3 Z,8P4(  
catch(IOException e) j94~c YV  
{ 0C.5Qx   
e.printStackTrace (); :-#7j} R&  
} R<_VWPlj  
[TQYu:e  
IP$eJL[&D"  
return n; `q\F C[W  
} dl[%C6  
?*$uj(  
Y'jgp Vt  
} 5x|$q kI  
wl%ysM| x  
O7_y QQAA  
/* "=K3sk  
**SiteInfoBean.java w)* H&8h@  
*/ 4"Qb^y  
package NetFox; fd #QCs  
F WU >WHX  
@`+\v mfD  
public class SiteInfoBean { Tc!n@!RA|  
_VjaTw8iM  
Ek_&E7  
private String sSiteURL; //Site's URL KPDJ$,:  
private String sFilePath; //Saved File's Path 6T+ym9  
private String sFileName; //Saved File's Name %).I &)i  
private int nSplitter; //Count of Splited Downloading File H"A@Q.'  
o3\^9-jmp  
= 03G~7B>  
public SiteInfoBean() 8@+<W%+th  
{//nSplitter的缺省值为5 901 5PEO  
//default value of nSplitter is 5 !-n* ]C  
this("","","",5); %-fS:~$  
} RTvOaZ  
-K$ugDi  
BMQ4i&kF|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Nxl#]  
{ OGLA1}k4  
sSiteURL= sURL; pYm#iz  
sFilePath = sPath; THX% z `  
sFileName = sName; ^8bc<c:P  
this.nSplitter = nSpiltter; nj00g>:>  
etX(~"gG_  
6 <`e]PT  
} 6C"zBJcGc  
N"RPCd_  
>ySO.S  
public String getSSiteURL() _<2{8>EVf  
{ \(=xc2  
return sSiteURL; DWx;cP8[  
} *kZH~]  
k^ fW /  
3?`TEw~'  
public void setSSiteURL(String value) G#f3 WpD  
{ W`oyDg,D  
sSiteURL = value; = =Q*|L-g  
} })kx#_o]'d  
1#;^ Z3  
xT* 3QwK  
public String getSFilePath() eHGx00:  
{ FYu30  
return sFilePath; `-cw[@uD  
} k#~oagW_Gw  
;gu4~LQw  
J(~1mIJjC  
public void setSFilePath(String value) 'r_Fi5[q  
{ [g: cG  
sFilePath = value; LfU? 1:Du  
} }M"])B I  
b KIL@AI  
-vc$I=b;  
public String getSFileName() ,CPAS}kS  
{ 91yYR*  
return sFileName; 6@47%%,}  
} E+e),qsbO  
_\,lv \u  
v$JW7CKA  
public void setSFileName(String value) i| ,}y`C#  
{ ./.aLTh  
sFileName = value; {(asy}a9K  
} *}Gys/\!S  
XhWo~zh"  
U1fqs{>  
public int getNSplitter() 2ve<1+V_  
{ r| \""  
return nSplitter; *wd=&Z^19  
} `(P71T  
XDyo=A]  
=WZ9|e  
public void setNSplitter(int nCount) `)KGajB  
{ N'l2$8  
nSplitter = nCount; m]Qs BK  
} PQYJn x}  
} :9x]5;ma  
rFm?Bu  
7PUy`H,&  
/* h -091N  
**Utility.java ` l'QAIo  
*/ g`.H)36  
package NetFox; xb9^WvV  
nox-)e  
fk1d iB  
public class Utility { Z0'LD<  
;Oq>c=9%  
0jxXUWO  
public Utility() 0(Z:QqpU$  
{ u}_x   
KIWHn_ :  
pX!T; Re;  
} 'IVC!uL,%  
60e{]}Z  
//线程睡眠 x5;D'Y t"|  
public static void sleep(int nSecond) [ z/G  
{ M _cm,|FF  
try{ /!6 VP |  
Thread.sleep(nSecond); nG?Z* n  
} l>BM}hS  
catch(Exception e) 4R8Qn^  
{ 83#<Yxk~  
e.printStackTrace (); T-7( 3#&  
} "qZTgCOY2  
} R `ob;>[Q  
Qn-nO_JL  
//日志 4W E)2vkS  
public static void log(String sMsg) w_~tY*IwB  
{ %X%f0J  
System.err.println(sMsg); )MoHY   
} Gb"kl.j  
e~,+rM  
/%t`0pi  
public static void log(int sMsg) f/0k,~,*  
{ h:FN&E c}  
System.err.println(sMsg); d}Y#l}!E6  
} gdyWuOxa|  
} ka(3ONbG  
 zNn  
P~x4h{~Gd  
/* jSdC1,wR  
**TestMethod.java ajkpU.6E:  
*/ ]S@DVXH  
package NetFox; \]S)PDqR  
=t~]@?]1D  
dEX67rUj;  
public class TestMethod { i`}9VaUG  
W%9~'pXgB  
@.G;dL.f{  
public TestMethod() ]]_c3LJ2`  
{ ///xx/weblogic60b2_win.exe W~l.feW$i  
try{ mr]~(]B?r  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); GFnwj<V+{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); lD# yXLaC\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u,`V%J?vW  
fileFetch.start(); R.GDCGAL  
} QMDkkNK  
catch(Exception e){e.printStackTrace ();} 9c0  
^0I"  
Qdc)S>gp  
} ;vk>k0S  
onv0gb/J  
&*Kk> 4  
public static void main(String[] args) yVpru8+eD  
{ VjeF3pmBa  
new TestMethod(); T=g2gmo9  
} 7o7FW=^  
} 8ddBQfCY  
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