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http断点续传简单实现(java)

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/* Y 8-;eqH  
**SiteFileFetch.java 3T /_#=9TV  
*/ gL &)l!2Y  
package NetFox;  e**5_L  
import java.io.*; _Qq lOc9  
import java.net.*; v\g1 w&PN  
EeQ2\'t  
w0O(>  
public class SiteFileFetch extends Thread { _&M^}||UH  
yBCLS550  
BQ=JZ4&  
SiteInfoBean siteInfoBean = null; //文件信息Bean ezA&cZ5  
long[] nStartPos; //开始位置 ,b<m],p  
long[] nEndPos; //结束位置 mYqLqezAA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 A>f rf[fAW  
long nFileLength; //文件长度 *|^|| bd  
boolean bFirst = true; //是否第一次取文件 RS|*3 $1  
boolean bStop = false; //停止标志 Z-L}"~  
File tmpFile; //文件下载的临时信息 ~ %Ij5PD  
DataOutputStream output; //输出到文件的输出流 Z6nQW53-  
FP")$ ,=s  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Ih[k{p  
public SiteFileFetch(SiteInfoBean bean) throws IOException ltv ~Kh  
{ w}YcAnuB{%  
siteInfoBean = bean; [[O4_)?el  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k_nQmU>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); M}`T-"qf  
if(tmpFile.exists ()) I0N~>SpZ5  
{ iGBHlw;A  
bFirst = false; SB:z[kfz|  
read_nPos(); )K]<\Q[  
} od^o9(.W^  
else %"ehZ d0r  
{ {5 3#Xd  
nStartPos = new long[bean.getNSplitter()]; vcZ"4%w  
nEndPos = new long[bean.getNSplitter()]; Y=/;7T  
} I5]58Ohx  
Qnx?5R-}ZU  
xiVbVr#[  
#+ {%>f  
} 1I%niQv5t  
L+lX$k  
%r@:7/  
public void run() O4!!*0(+91  
{ _y:a Pn  
//获得文件长度 \okvL2:!  
//分割文件 H|3CZ=U?  
//实例FileSplitterFetch IH"_6s#$&  
//启动FileSplitterFetch线程 uM[[skc  
//等待子线程返回 EiS2-Uh*TT  
try{ Icx)+Mq  
if(bFirst) aNgJm~K0P  
{ KDr)'gl&  
nFileLength = getFileSize(); V$ho9gQ!l[  
if(nFileLength == -1) !,~C  
{ Gw#z:gX2  
System.err.println("File Length is not known!"); {5SJ0'.B2g  
} R8|F qBs  
else if(nFileLength == -2) Yez  
{ aW#^@||B  
System.err.println("File is not access!"); ]sqp^tQ`e  
} LAGg(:3f3  
else -3SRGr  
{ C9j5Pd5q1L  
for(int i=0;i<nStartPos.length;i++) "uBr]N:  
{ 6Z-[-0o+g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \wp8kSzC  
} }7i}dyQv}  
for(int i=0;i<nEndPos.length-1;i++) b{,vZhP-  
{ .p'\@@o5  
nEndPos = nStartPos[i+1]; #B__-"cRv  
} 7 .xejz  
nEndPos[nEndPos.length-1] = nFileLength; ,%KMi-w]q,  
} YVO~0bX:  
} XeXK~  
!/Wv\qm  
9$^v*!<z\  
//启动子线程 KA."[dVa  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +}C M2>M  
for(int i=0;i<nStartPos.length;i++) G 'CYvV  
{ %sS7o3RW\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zU# OjvNk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), KvEZbf 3f  
nStartPos,nEndPos,i); mZ.E;X& ,*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t`0(5v  
fileSplitterFetch.start(); ^ |>)H  
} wtQ(R4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TZ:dY x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); EU()Nnm2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?D]T| =EZY  
nEndPos = " + nFileLength); u &{|f  
// fileSplitterFetch[nPos.length-1].start(); %/wfYRp*  
9z(h8H  
m A|"  
//等待子线程结束 cKAZWON8;v  
//int count = 0; j*jq2u  
//是否结束while循环 u_S>`I  
boolean breakWhile = false; "HbrYYRb'  
\JGRd8S[  
p+R8Mo;I  
while(!bStop) <$`ud P@  
{ pl.=u0 *  
write_nPos(); <~Tfi*^+  
Utility.sleep(500); 7@i2Mz/eV  
breakWhile = true; [oS.B\Vc  
JmVha!<qk  
;%PdSG=U  
for(int i=0;i<nStartPos.length;i++) ] I0(_e|z}  
{ +isaqfy/  
if(!fileSplitterFetch.bDownOver) ]TKM.[[  
{ d?(eL(W  
breakWhile = false; H@8 ;6D  
break; o #F03  
} I\ y>I?X  
} #|{^k u  
if(breakWhile) Y&DC5T]  
break; fpvzx{2  
E %> ){Y)  
_:l<4u !  
//count++; HltURTbI  
//if(count>4) ,_yf5 a  
// siteStop(); As*59jkB  
} lb`2a3W/  
y8\4TjS1  
V~qlg1h  
System.err.println("文件下载结束!"); oNBYJ]t  
} g/m%A2M&aH  
catch(Exception e){e.printStackTrace ();} ,h$j%->U  
} 3mM.#2=@>  
atWAhN  
XWFuAE  
//获得文件长度 w~=@+U$f  
public long getFileSize() t2vo;,^euL  
{ Ic&Jhw;]z  
int nFileLength = -1; [KjL`  
try{ @g'SH:}  
URL url = new URL(siteInfoBean.getSSiteURL()); @y`7csb p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =9vmRh? 8  
httpConnection.setRequestProperty("User-Agent","NetFox"); j*;/Cah]k  
x kebel`%  
g3uI1]QXLg  
int responseCode=httpConnection.getResponseCode(); EYF]&+ 9  
if(responseCode>=400) ' 5"`H>[  
{ %j?<v@y  
processErrorCode(responseCode); a=3{UEi'o  
return -2; //-2 represent access is error +']S  
} !U !}*clYL  
zos#B30  
@VcSK`  
String sHeader; T5di#%: s  
2*1s(Jro  
~2*8pb 4  
for(int i=1;;i++) $:MO/Su z{  
{ B%Sp mx8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K%"cVqb2V  
//Utility.log(in.readLine()); 0UT2sM$  
sHeader=httpConnection.getHeaderFieldKey(i); ?QXo]X;f&  
if(sHeader!=null) D2}nJFR ]  
{ {CR'Z0  
if(sHeader.equals("Content-Length")) .4wp  
{ xN#. Pm~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8TnByKZz  
break; $?u ^hMU=  
} i bwnK?ZA  
} Ka\%kB>*`  
else SggS8$a`  
break; fX2PteA0qX  
} `&yUU2W  
} OVm $  
catch(IOException e){e.printStackTrace ();} pJE317 p'  
catch(Exception e){e.printStackTrace ();} U ]6 Hml;l  
pB;p\9A*q  
jE{2rw$ZJ?  
Utility.log(nFileLength); l`R/WC  
K-nf@o+  
hOSkxdi*^  
return nFileLength; nn_j"Nu  
} #ab=]}2W_g  
Mb(aI!;A  
^KJIT3J(#  
//保存下载信息(文件指针位置) Gm.n@U p  
private void write_nPos() ryq95<lF  
{ Y?z@)cL  
try{ +cVnF&@$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j5:{H4?  
output.writeInt(nStartPos.length); {>c O&eiCt  
for(int i=0;i<nStartPos.length;i++) ivbuS-f =r  
{ Whq@>pX8  
// output.writeLong(nPos); ymBevL  
output.writeLong(fileSplitterFetch.nStartPos); _KkLH\1g$  
output.writeLong(fileSplitterFetch.nEndPos); V4OhdcW{  
} /*bS~7f1  
output.close(); ?Q]{d'g(sx  
} Kj_hCSvf3e  
catch(IOException e){e.printStackTrace ();} _azg 0.)  
catch(Exception e){e.printStackTrace ();} l*]*.?m/5  
} GiN\nu<!  
ccJ@jpXI  
>]k'3|vV  
//读取保存的下载信息(文件指针位置) yjVPaEu]aU  
private void read_nPos() <"@~  
{ Nd~?kZZu  
try{ %Y` @>P'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )-2o}KU]>  
int nCount = input.readInt(); E VBB:*q6  
nStartPos = new long[nCount]; j#b?P=|l  
nEndPos = new long[nCount]; :hG?} [-2  
for(int i=0;i<nStartPos.length;i++) $3sS&i<  
{ !0~$u3[b  
nStartPos = input.readLong(); Fr)G h>  
nEndPos = input.readLong(); u4=j!Zb8}  
} |wZ8O}O{E  
input.close(); F}A@H<?  
} O=#FpPHrdw  
catch(IOException e){e.printStackTrace ();} g`!:7|&,_  
catch(Exception e){e.printStackTrace ();} J8$G-~MeJ  
} DLkNL?a  
$@t-Oor;  
_gB`;zo  
private void processErrorCode(int nErrorCode) lu(<(t,Lbs  
{ V,($I'&/  
System.err.println("Error Code : " + nErrorCode); 92GO.xAD?  
} p IXBJk  
5yO6szg  
j3rBEQ,R  
//停止文件下载 o)7gKWjujP  
public void siteStop() -tSWYp{  
{ tH<v1LEZN  
bStop = true; 9/MUzt  
for(int i=0;i<nStartPos.length;i++) `av8|;  
fileSplitterFetch.splitterStop(); 8ltHR]v  
AyKaazm]9  
](vsh gp2  
} Z xLjh  
} l,*v/95h  
//负责部分文件的抓取 =/" Of  
**FileSplitterFetch.java rO/mK$  
*/ >'/G:\M>A  
package NetFox; k=O2s'F`  
)kl| 5i  
Mu18s}  
import java.io.*; 3mgFouX2x,  
import java.net.*; vt[4"eU  
zqqpBwk#  
j[yGfDb  
public class FileSplitterFetch extends Thread { A8hj"V47  
sf]y\_zU  
h%(dT/jPL)  
String sURL; //File URL {>G\3|^D  
long nStartPos; //File Snippet Start Position s@f4f__(]  
long nEndPos; //File Snippet End Position l0g#&V--  
int nThreadID; //Thread's ID Z bxd,|<|  
boolean bDownOver = false; //Downing is over 7ju7QyR  
boolean bStop = false; //Stop identical Gu<3*@Ng  
FileAccessI fileAccessI = null; //File Access interface I~MBR2$9  
yE-&TW_q:>  
@dcT8 YC  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _Q/D%7[pa  
{ (^Xp\dyZL  
this.sURL = sURL; pK4I?=A'  
this.nStartPos = nStart; m~#S76!w  
this.nEndPos = nEnd; '!Vn  
nThreadID = id; *~M=2Fj;i  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Tn/T :7C  
} iqghcY)  
!'B.ad  
i)\`"&.j>N  
public void run() (hd^  
{ q~r )B}  
while(nStartPos < nEndPos && !bStop) \CB{Ut+s  
{ LS4c|Dv  
cg<10KT  
 o )cd!,h  
try{ r~u/M0h `  
URL url = new URL(sURL); BXaA#} ;e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,>2ijk#  
httpConnection.setRequestProperty("User-Agent","NetFox"); }.4`zK&SB  
String sProperty = "bytes="+nStartPos+"-"; KSuP'.l  
httpConnection.setRequestProperty("RANGE",sProperty); 1#Dpj.cO#  
Utility.log(sProperty); xzy7I6X  
,Vt7Kiu  
'  G-]>  
InputStream input = httpConnection.getInputStream(); `Qv7aY  
//logResponseHead(httpConnection); OqY8\>f-  
B>t$Z5Q^X  
O:RPH{D  
byte[] b = new byte[1024]; 9C$b^wHd  
int nRead; 8=T;R&U^M  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) T%KZV/  
{ %]>c4"H  
nStartPos += fileAccessI.write(b,0,nRead); T^aEx.`O}`  
//if(nThreadID == 1) +XJj:%yt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KB7CO:  
} 9<WMM)  
2<yi8O\  
_C&2-tnp  
Utility.log("Thread " + nThreadID + " is over!"); -fz |  
bDownOver = true; I_'S|L  
//nPos = fileAccessI.write (b,0,nRead); }-)2CEj3L%  
} [U]*OQH`e  
catch(Exception e){e.printStackTrace ();} A"\kdxC  
} 4t|g G`QW7  
} Vur$t^zE  
LSNa  
%U)/>Z  
//打印回应的头信息 $91c9z;f^  
public void logResponseHead(HttpURLConnection con) 22`W*e@6h  
{ p< '#f,o  
for(int i=1;;i++) ~o= Sxaf  
{ L"1UUOKy  
String header=con.getHeaderFieldKey(i); m7^aa@^m  
if(header!=null) wS <d8gw  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Eg5|XV  
Utility.log(header+" : "+con.getHeaderField(header)); &iR>:=ks N  
else 6/wAvPB$  
break; CwTx7 ^qa  
} A0cC)bd&  
} X + *@  
m-dne/%_  
za1MSR  
public void splitterStop() *|Q'?ty(x  
{ e4yd n  
bStop = true; .rD@Q{e50  
} 2+TCFpv  
*.r i8  
92WvD  
} :qc@S&v@]  
XN5EZ#  
8*H-</ =  
/* vmvk  
**FileAccess.java EJ.oq*W!*J  
*//文件访问(定位,写) he wX)  
package NetFox; x %L2eXL  
import java.io.*; U voX\  
GX&BUP\  
\$/)o1SG  
public class FileAccessI implements Serializable{ x:88E78  
yN5g]U. Q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4cRF3$a md  
RandomAccessFile oSavedFile; $}jp=?,t  
long nPos; 'LpJ:Th  
tlV>  
BdG~y1%:  
public FileAccessI() throws IOException 84DneSpHsp  
{ VtUe$ft  
this("",0); sczN0*w&C  
} ,u#uk7V  
=GL}\I  
cZ k? o  
public FileAccessI(String sName,long nPos) throws IOException 8E&}+DR?  
{ 2xhwi.u  
oSavedFile = new RandomAccessFile(sName,"rw"); Sf B+;i'D  
this.nPos = nPos; Yew n  
oSavedFile.seek(nPos); cNtGjLpx;  
} Ah;2\0|t  
^G[xQcM73  
-X'HZ\)  
public synchronized int write(byte[] b,int nStart,int nLen) bvuoGG*  
{ `ky< *  
int n = -1; &8_]omuNV  
try{ ]iRE^o6  
oSavedFile.write(b,nStart,nLen); *&q\)\(3w  
n = nLen; WM.JoQ  
} 0Jm6 r4s?  
catch(IOException e) KiT>W~  
{ ,a eQXI#@  
e.printStackTrace (); 8;ke,x  
} S(.AE@U  
~YA* RCe  
\{t#V ~  
return n; a*$to/^r  
} mv O!Y  
k<Z^93 S  
@*]l.F   
} ^ llZf$`  
}&I\a  
]>E*s3h  
/* PUV)w\!&is  
**SiteInfoBean.java 9W:oo:dK F  
*/ _T&?H&#  
package NetFox; J0*hJ-/u  
_G|hKk^,  
K 4QJDC8  
public class SiteInfoBean { HYyO/U9z|I  
p~6/+ap  
8W#/=Xh?  
private String sSiteURL; //Site's URL ?:vp3f#  
private String sFilePath; //Saved File's Path y  >r7(qg  
private String sFileName; //Saved File's Name n$ $^(-g@)  
private int nSplitter; //Count of Splited Downloading File lqn7$  
B8UtD  
5ppOG_  
public SiteInfoBean() 'MRvH lCM  
{//nSplitter的缺省值为5 $}_N379&  
//default value of nSplitter is 5 bXF>{%(}E  
this("","","",5); Oi AZA<  
} -$**/~0zU  
U`N|pPe:w  
AD#]PSB  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) V>ML-s9  
{ '9c`[^  
sSiteURL= sURL; GL[#XB>n  
sFilePath = sPath; 4z#{nZG  
sFileName = sName; NdGIH/Y;M  
this.nSplitter = nSpiltter; p4C w#)BaS  
ZQXv-"  
[zl@7X1{_  
} _8P"/( `Rw  
) DXN|<A  
_x&;Fa%  
public String getSSiteURL() gD10C,{  
{ <f.*=/]W2  
return sSiteURL; k"D6Vyy`  
} n8UQIa4&=  
$R(?@B(  
5b45u 6  
public void setSSiteURL(String value) x|U~?  
{ F-[zuYGp  
sSiteURL = value; 7[h_"@_A7  
} XK??5'&{  
IROX]f}r(  
4)0 %^\p  
public String getSFilePath() QEKSbxL\W  
{ [zv>Wlf,%  
return sFilePath; !l|v O(  
} 2_M+akqy^  
4 AZ~<e\  
Ls{z5*<FM  
public void setSFilePath(String value) b&[9m\AX`  
{ aSdh5?  
sFilePath = value; H e ABU(o4  
} !>fYD8Ft,  
yTzP{I  
oJa6)+b(3  
public String getSFileName() YL-/z4g  
{ xFxl9oM."  
return sFileName; WA}<Zme3[  
} _J(n~"eR  
xxkU u6x#  
/WlK*8C  
public void setSFileName(String value) nv&uhu/q  
{ 1{+x >Pv:  
sFileName = value; g?N~mca$  
}  N1,=5P$  
#=F"PhiX`  
uT'_}cw  
public int getNSplitter() rE0?R( _  
{ h07Z.q ;  
return nSplitter; pm$2*!1F(  
} K*iy^}  
,<?iL~> %  
V ij P;  
public void setNSplitter(int nCount) ?#; oqH<  
{ = ms(dr^n  
nSplitter = nCount; Rs_0xh  
} 8|^dM$  
} Ww5c9orXn  
6BM[RL?T  
[ []'U'  
/* 0^'A^  
**Utility.java MV +R$  
*/ ^kZfE"iE2  
package NetFox; "<o[X ?u  
M S 3?#b  
wKF #8Y  
public class Utility { - s[=$pDU  
piYv }4;:(  
OQzJRu)mF#  
public Utility() F*V<L   
{ jv $Y]nf  
RtVy^~=G  
r /v'h@  
} <;O=h; ~|  
,XT#V\qne  
//线程睡眠 nk.Y#+1)  
public static void sleep(int nSecond) [Du@go1C  
{ GT\, @$r  
try{ 3t<XbHF9  
Thread.sleep(nSecond); +|}R^x`z  
} :g)0-gN   
catch(Exception e) k. bzh.  
{ E)==!T@E  
e.printStackTrace (); v*Tliw`-U  
} hsV+?#I  
} )aoB -Lu  
is=sV:j:  
//日志 +mRFHZG  
public static void log(String sMsg) /H#- \r&r  
{ ?^Sk17G  
System.err.println(sMsg); WrK!]17or  
} rZRcy9$y>  
eXJt9olI  
5dffF e  
public static void log(int sMsg) ]zp5 6U|xa  
{ 3:Bwf)*  
System.err.println(sMsg); _XT],"  
} '[#a-8-JY_  
} ~3}Gu^@  
g\MHv#v*k  
Pn@k)g  
/* %bI(   
**TestMethod.java |8I #`  
*/ 8r '  
package NetFox; .DSn H6O  
(IX iwu  
^l1tQnj)7  
public class TestMethod { =H*}{'#  
shW$V93<  
U3r[ysf  
public TestMethod() ( Lj{V}^  
{ ///xx/weblogic60b2_win.exe \)'nxFKqV  
try{ `|K,E  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); b?Wg|D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3L/qU^`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =a rk?<E  
fileFetch.start(); ~~:w^(s9  
} j,Sg?&"%=  
catch(Exception e){e.printStackTrace ();} ~ILig}I  
;9r Z{'i+|  
 Q(SVJ  
} 9 x WC<i  
EubR] ckB  
\RN,i]c-g/  
public static void main(String[] args) _'&N01  
{ '!`%!Xg  
new TestMethod(); e;b,7Qw  
} ~82[pY  
} o?\)!_Z|  
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