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http断点续传简单实现(java)

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/* aasoW\UG  
**SiteFileFetch.java n*o-Lo+Fe.  
*/ O8^A5,2@3>  
package NetFox; >3ZFzh&OYQ  
import java.io.*; \ S_Ou   
import java.net.*; G3t xj  
_ "E$v&_  
{M3qLf~z#C  
public class SiteFileFetch extends Thread { K~uXO  
!H#bJTXB  
O3;u G.:1  
SiteInfoBean siteInfoBean = null; //文件信息Bean ky8_UnaO  
long[] nStartPos; //开始位置 84$nT>c  
long[] nEndPos; //结束位置 ?xA:@:l/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 XFg 9P}"  
long nFileLength; //文件长度 m )8BgCy  
boolean bFirst = true; //是否第一次取文件 v0ujdp,B  
boolean bStop = false; //停止标志  vx\r!]  
File tmpFile; //文件下载的临时信息 ih)zG  
DataOutputStream output; //输出到文件的输出流 $Y;U[_l#  
v/@^Q1 G/:  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) y>:N{|  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1}S S+>`  
{ rUwZMli  
siteInfoBean = bean; bw(a6qKK  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); phQU D  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); EJj.1/]|r  
if(tmpFile.exists ()) 5]~'_V  
{ -M~8{buxv  
bFirst = false; ,aOl_o -&  
read_nPos(); _> f`!PlB|  
} a Ve'ry  
else N1Ng^aY0  
{ ?U%QG5/>  
nStartPos = new long[bean.getNSplitter()]; v>:Ur}u!D  
nEndPos = new long[bean.getNSplitter()]; f< ia(d  
} imo$-}A  
#TeG-sFJg@  
]"r&]qx7  
4hO!\5-w:  
} V08?-Iz$  
gK_Ymq5>"M  
,%6P0#-  
public void run() C7XxFh  
{ oxC[F*mD  
//获得文件长度 \4&fxe  
//分割文件 u&^b~# T  
//实例FileSplitterFetch UG'Q]S#!  
//启动FileSplitterFetch线程 i% w3/m  
//等待子线程返回 8k2?}/+  
try{ F7 5#*  
if(bFirst) ?e` ^P   
{ rTM}})81  
nFileLength = getFileSize(); hmvfw:Nq4  
if(nFileLength == -1) kC WEtbz1  
{ oNr-Q& C,  
System.err.println("File Length is not known!"); :C7_Jp*Qv  
} 6 rh5h:  
else if(nFileLength == -2) W~6EEyD%  
{ A]<y:^2])C  
System.err.println("File is not access!"); f}aL-N~  
} t 4PK}>QW  
else bhID#&  
{ .O74V~T  
for(int i=0;i<nStartPos.length;i++) pqk?|BvpK_  
{ 56}U8X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NYyh|X:m  
} gRrL[z  
for(int i=0;i<nEndPos.length-1;i++) |^0XYBxQ  
{ H]P. x!I  
nEndPos = nStartPos[i+1]; J cPtwa;q@  
} _7<FOOM%8y  
nEndPos[nEndPos.length-1] = nFileLength; J{'>uD.@  
} 3?[dE<  
} u&1q [0y  
~:0sk"t$1  
;l4[%xld  
//启动子线程 #G .ulX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3%l*N&gsg:  
for(int i=0;i<nStartPos.length;i++) ]@dZ{H|  
{ ?b*s. ^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RdWRWxTn8+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ? Fi=P#  
nStartPos,nEndPos,i); ]|!OP  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F{Z~ R  
fileSplitterFetch.start(); }e!x5g   
} N+++4;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ! _f9NK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); YT8vP~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5}:-h>  
nEndPos = " + nFileLength); .|hf\1_J  
// fileSplitterFetch[nPos.length-1].start(); fo5iJz"Z  
hq%?=2'9?  
o%v0h~tn  
//等待子线程结束 uH/J]zKR  
//int count = 0; Z&#('Z  
//是否结束while循环 0M*Z'n +  
boolean breakWhile = false; S\4tzz @  
B&\IGWG(  
FR$:"  
while(!bStop) W6f/T3  
{ 4S5,w(6N  
write_nPos(); ao%NK<Lt  
Utility.sleep(500); &wi e]  
breakWhile = true; E'G4Y-  
N8k00*p65  
6 2'j!"xv  
for(int i=0;i<nStartPos.length;i++) >v:y?A,  
{ 5Ec6),+&  
if(!fileSplitterFetch.bDownOver) t=|evOz]  
{ (gy#js #  
breakWhile = false; &{ay=Mj  
break; 5XO;N s  
} Q7*SE%H  
} YX=a#%vrl  
if(breakWhile) kv3E4,<9  
break; 3_txg>P"  
4~y(`\0?4  
%oq{L]C(rf  
//count++; +Fuqch jq  
//if(count>4) M%Ji0v38  
// siteStop(); G]D+Sl4<7i  
} [f)cL6AeF  
yGWxpzmRS  
bW$J~ynM  
System.err.println("文件下载结束!"); 6,)[+Bl  
} Q 7   
catch(Exception e){e.printStackTrace ();} ~T9/#-e>BF  
} QFw  +cy  
* vflscgt  
_I:~@  
//获得文件长度 NYE` Kin-  
public long getFileSize() hHN'w73z  
{ &Nj3h(Ll  
int nFileLength = -1; @HQ`~C#Z'  
try{ )#P; x "  
URL url = new URL(siteInfoBean.getSSiteURL()); 1>*#%R?W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  9XP o3;  
httpConnection.setRequestProperty("User-Agent","NetFox"); u\ #"L  
a&tSj35*6  
]4~lYuI4  
int responseCode=httpConnection.getResponseCode(); K#EvFs`s;  
if(responseCode>=400) V@Rrn <l  
{ E^QlJ8  
processErrorCode(responseCode); #OIcLEn%  
return -2; //-2 represent access is error aEM%R<e  
} ' qWALu  
m5L-67[sB  
+g` 'J$  
String sHeader; BbW^Wxd3  
f%Ns[S~r  
_jJPbKz  
for(int i=1;;i++) q;QbUO  
{ /]=C{)8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >ZPsjQuf"  
//Utility.log(in.readLine()); )Gj8X}DM  
sHeader=httpConnection.getHeaderFieldKey(i); i;NUAmx  
if(sHeader!=null) |o{:ZmzM  
{ /`f^Y>4gD  
if(sHeader.equals("Content-Length")) B-.gI4xa  
{ AmaT0tzJC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]e^c=O`$  
break; }R1< 0~g  
} s>0't  
} T,]7ICF#  
else R<[qGt|L  
break; :A1{d?B  
} b?TO=~k,  
} %ZNI:Uh  
catch(IOException e){e.printStackTrace ();} XM1WfjE\  
catch(Exception e){e.printStackTrace ();} Z3{>yYR+  
7B b9 t  
v5By:z  
Utility.log(nFileLength); Av"R[)  
"$N#p5  
vY%d   
return nFileLength; 9{-EJ)  
} vWRju*Z&  
K%"5ImM  
k *Q<3@S  
//保存下载信息(文件指针位置) YQ39 A_e g  
private void write_nPos() zN!ZyI$nqP  
{ @\0Eu212  
try{ 99}(~B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?0)&U  
output.writeInt(nStartPos.length); F">Qpgt  
for(int i=0;i<nStartPos.length;i++) eln&]d;  
{ q8s0AN'@t'  
// output.writeLong(nPos); O J/,pLYu  
output.writeLong(fileSplitterFetch.nStartPos); Ko;{I?c  
output.writeLong(fileSplitterFetch.nEndPos); }D7I3]2>   
} b+@JY2dvj  
output.close(); 0|$v-`P$  
} CPP` qt%f  
catch(IOException e){e.printStackTrace ();} nyBJb(5"B  
catch(Exception e){e.printStackTrace ();} R(2tlZ  
} Cz 72?[6  
+)j$|x~(A  
>iD )eB  
//读取保存的下载信息(文件指针位置) _acE:H  
private void read_nPos() %;e/7`>Ma  
{ )^4\,u\@  
try{ T(e!_VY|m  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3T"j)R_=l  
int nCount = input.readInt(); 2C/$Ei^t  
nStartPos = new long[nCount]; /h*>P:i].  
nEndPos = new long[nCount]; P^w#S  
for(int i=0;i<nStartPos.length;i++) |_`E1Y}}  
{ U7oo$gW%|T  
nStartPos = input.readLong(); i|T)p_y(!a  
nEndPos = input.readLong(); r.#t63Rb  
} f2^r[kPX"  
input.close(); wtc!>  
} r9 ui|>U"  
catch(IOException e){e.printStackTrace ();} v=_6XF  
catch(Exception e){e.printStackTrace ();} *Txl+zTY  
} !eEHmRgg4  
|`lzfe  
5Cq{XcXV  
private void processErrorCode(int nErrorCode) ix(=3 /Dgz  
{ HuwU0:*  
System.err.println("Error Code : " + nErrorCode); 2_zp:v  
} O9EKRt  
I9:Cb)hbU]  
l~6?kFy9h  
//停止文件下载 >p.O0G gg  
public void siteStop() uoHNn7W  
{ %,D<O,N  
bStop = true; &jsVw)Ue  
for(int i=0;i<nStartPos.length;i++) 87=^J xy  
fileSplitterFetch.splitterStop(); bzX\IrJpOZ  
q)Fq i  
$:  ]o]a  
} TiYnc3Bz}J  
} 7b<je=G6PA  
//负责部分文件的抓取 ai nG6Y<O`  
**FileSplitterFetch.java \8<BLmf4U  
*/ Hm$=h>rY9[  
package NetFox; =,Dqqf  
WAn~ +=Ax  
B>GE 9y5  
import java.io.*; =0G!f$7^i  
import java.net.*; _~*,m#uxJ  
N 5i+3&  
Dh5X/y  
public class FileSplitterFetch extends Thread { H63,bNS s  
_T2=J+"-Kp  
)('%R|$ /  
String sURL; //File URL Gm(b/qDDe  
long nStartPos; //File Snippet Start Position L ]w/P|  
long nEndPos; //File Snippet End Position D3)zk@N  
int nThreadID; //Thread's ID );Z1a&K5k  
boolean bDownOver = false; //Downing is over 9A,^c;  
boolean bStop = false; //Stop identical Gi "941zVl  
FileAccessI fileAccessI = null; //File Access interface <L`"!~Q  
7.Z@Wr?  
B<~ NS)w  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (;q\}u  
{ cG?cUw).E  
this.sURL = sURL; n84GZ5O>7  
this.nStartPos = nStart; | fSe>uVZ  
this.nEndPos = nEnd; U7I qST  
nThreadID = id; Kt"BE j  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k'#(1(xj  
} ik!..9aB  
]p;FZ4-T  
xA9:*>+>  
public void run()  >lBD<;T  
{ (HSgEs1d  
while(nStartPos < nEndPos && !bStop) g_G6~-.9I  
{ e_V O3"  
:PtF+{N>  
ppFe-wY  
try{ tUgEeh6  
URL url = new URL(sURL); 2Sh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ds&e|VSH;  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]ut5S>,"  
String sProperty = "bytes="+nStartPos+"-"; $ZNu+tn Y  
httpConnection.setRequestProperty("RANGE",sProperty); $dA-2e1 0  
Utility.log(sProperty); Q",0F{'  
8HRmQ  
e0J6Ae4V[  
InputStream input = httpConnection.getInputStream(); z,VD=Hnz  
//logResponseHead(httpConnection); jK' N((Hz  
^D<r  
|]aE<`D  
byte[] b = new byte[1024]; KyzFnVH3)  
int nRead; ~_s{0g]B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) HW7; {QMg  
{ zkO<-w  
nStartPos += fileAccessI.write(b,0,nRead); ] Puy!Q  
//if(nThreadID == 1) bd<m%OM""  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &NSY9'N,  
} Fr%d}g  
X+~ XJ  
b*FC\ :\  
Utility.log("Thread " + nThreadID + " is over!"); Le*.*\  
bDownOver = true; D`xHD#j h  
//nPos = fileAccessI.write (b,0,nRead); 59#lU~Kv  
} H6&J;yT}  
catch(Exception e){e.printStackTrace ();} 5ux`U{`m  
} me'd6!O9-  
} x3u4v~ "-  
cZ<A0  
6<'21  
//打印回应的头信息 8P"_#M?!  
public void logResponseHead(HttpURLConnection con) .58qL-iC  
{ 4WE6fJ2X  
for(int i=1;;i++) Y;)dct  
{ Dc+'<"  
String header=con.getHeaderFieldKey(i); ixV0|P8,c  
if(header!=null) r YF #^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }=|!:kiE  
Utility.log(header+" : "+con.getHeaderField(header)); ~j-cS J3  
else {O+Kw<d  
break; KL ?@@7  
} 8@PX7!9  
} TARXx>  
Q7g>4GZC  
5bA)j!#)|X  
public void splitterStop() ki{3IEOr}  
{ z.CywME<)t  
bStop = true; 5l,ZoB8  
} Fh*j#*oe  
wQ%mN[  
0jzbG]pc:E  
} @o-B{ EH8  
LC})ciWa  
W,K%c=  
/* (?H0+zws^  
**FileAccess.java & u!\<\  
*//文件访问(定位,写) nN~~cV  
package NetFox; @?[1_g_'P  
import java.io.*; !=y]Sv~h  
rLU/W<F8  
sO5?aB&  
public class FileAccessI implements Serializable{ 8&Myva  
&bhq`>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 h1(j2S`:  
RandomAccessFile oSavedFile; cS.-7  
long nPos; (4@lKKiU%H  
5o/&T"]@  
XK"-'  
public FileAccessI() throws IOException Uh'#izm[l  
{ Lgz$]Jbl8  
this("",0); 2jbIW*  
} /1 RAAa  
\V>?Do7  
+`sv91c  
public FileAccessI(String sName,long nPos) throws IOException gt\MS;jMa  
{ St<mDTi  
oSavedFile = new RandomAccessFile(sName,"rw"); .@"q$\  
this.nPos = nPos; @w>zF/  
oSavedFile.seek(nPos); WsFk:h'r  
} tV9L D>3  
lKkN_ (/j  
9z I.pv+]  
public synchronized int write(byte[] b,int nStart,int nLen) @VN&t:/l  
{ @Eb2k!T  
int n = -1; ~Xlrvb}LP  
try{ ?go:e#  
oSavedFile.write(b,nStart,nLen); c!hwmy;  
n = nLen; n9;;x%6.I  
} 9=,uq;  
catch(IOException e) zyg:nKQW  
{ m>}8'N)  
e.printStackTrace (); /cK%n4l.y  
} IG?'zppjd6  
m'-|{c  
`funE:>,  
return n; j,d*?'X  
} X1tXqHJF}  
t |W)   
-B$~`2-  
} /j"sS2$U  
^>?CMcN4*  
AkU<g  
/* + <c^=&7Lq  
**SiteInfoBean.java s!+"yK  
*/ 4Iq'/r  
package NetFox; z5*=MlZ)R.  
[~\PQYm'  
CU:o*;jP  
public class SiteInfoBean { dx,=Rd5'  
&ff&Y.q~  
y[@\j9Hq  
private String sSiteURL; //Site's URL 93IFcmO.H@  
private String sFilePath; //Saved File's Path "7d-z<^n  
private String sFileName; //Saved File's Name z^nvMTC  
private int nSplitter; //Count of Splited Downloading File =N);v\ Q$!  
O9(r{Vu7u  
`Y40w#?uW  
public SiteInfoBean() 0)m8)!gj  
{//nSplitter的缺省值为5 Zs2-u^3&  
//default value of nSplitter is 5 I =Wc&1g  
this("","","",5); %g]vxm5?  
} zu2HH<E  
Q/I)V2a1i  
nH !3(X*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $XBAZ<"hd  
{ "Dy'Kd%,%/  
sSiteURL= sURL; Z.i{i^/#(  
sFilePath = sPath; %b?$@H-Re  
sFileName = sName; o$.e^XL  
this.nSplitter = nSpiltter; !5}l&7:(MN  
|DF9cd^  
i v(5&'[p  
} "tS'b+SJ-S  
ZiFooA  
JM.XH7k  
public String getSSiteURL() 'rb'7=z5  
{ .r+hERcB  
return sSiteURL; uqyB5V0gh  
} "k$JP  
d h^^G^  
$!A:5jech  
public void setSSiteURL(String value) f]8I64  
{ ]J2:194  
sSiteURL = value; lo&#(L+2  
} W&"|}Pi/  
$mA5@O~C5\  
IB9%QW"0  
public String getSFilePath() nL]^$J$  
{ P5QQpY{<I  
return sFilePath; ']o od!  
} /"qcl7F  
V_U'P>_I  
M~6@20$oW  
public void setSFilePath(String value) O$ !* %TL  
{ !wLg67X$ -  
sFilePath = value; S\NL+V?7h  
} eyw'7  
VY 1vXM3y  
qBk``!|s]  
public String getSFileName() oCi ~P}r  
{ CPazEe1S  
return sFileName; S(eQ{rSs  
} Ja^ 5?Ar|  
1D([@)^  
 ZC^C  
public void setSFileName(String value) '3l$al:H^  
{ 5iFV;W  
sFileName = value; VFD%h }  
} MN;/*t  
cJ}QXuuUv  
oholt/gb+0  
public int getNSplitter() 1@sM1WM X  
{ 0WxCSL$#I  
return nSplitter; r@)A k  
} QBE@(2G}C  
j,%EW+j$  
T*q"N?/4  
public void setNSplitter(int nCount) !#D=w$@r:  
{ v$|mo;6  
nSplitter = nCount; \94jrr  
} {M~lbU  
} V`a+Hi<P\  
XbvDi+R 2A  
17UK1Jx,  
/* $.e)  
**Utility.java ,qFA\cO*  
*/ ~0tdfK0c  
package NetFox; yDd[e]zS`  
8LM #WIm?  
T.?k>A k  
public class Utility { ( 76{2  
- HOnB=  
nf%4sIQ*x  
public Utility() 7$T8&Mh  
{ &&RA4  
!r&Bn6*  
\%_ZV9cKF  
} r)l`  
6517Km 4-  
//线程睡眠 j64 4V|z  
public static void sleep(int nSecond) $@[)nvV\  
{ MR9/Y:Nm  
try{ x6yW:tUG5  
Thread.sleep(nSecond); , r+"7$  
} XdIah<F2  
catch(Exception e) JAb$M{t  
{ mA{#]Yvf1  
e.printStackTrace (); =&NOHT>  
} a>Re^GT+z  
} WVL#s?=g  
J 3?Dj  
//日志 hH4o;0rqJ  
public static void log(String sMsg) Sni=gZK  
{ 6&!l'[hU  
System.err.println(sMsg); (.^8^uc 7X  
} 6Dzs?P  
j=3-Qk`"/|  
_-a|VTM  
public static void log(int sMsg) QPg2Y<2  
{ E[S':Q  
System.err.println(sMsg); @W9H9 PWv&  
} O3_B<Em  
} co]Gmg6p  
Va9q`XbyO  
V<0$xV1b|=  
/* d(l|hmj4j9  
**TestMethod.java ofwQ:0@  
*/ qC j*>D  
package NetFox; *wUdC  
@l,{x|00  
q+/l"&j.  
public class TestMethod { BjD&> gO)  
EzP#Mnz^  
bXl8v  
public TestMethod() l P0k:  
{ ///xx/weblogic60b2_win.exe Ow3a0cF[9  
try{ ,C!n}+27  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xii$e  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); BvJ=iB<E  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ONWO`XD  
fileFetch.start(); =J.EH|  
} 8t``NZ[  
catch(Exception e){e.printStackTrace ();} %|?1B$s0  
!GNXt4D  
1o#vhk/ "+  
} zz3 r<?#5  
[:pl-_.C  
DcU C,  
public static void main(String[] args) Q&wYc{TUbm  
{  ^@q#$/z  
new TestMethod(); QN #)F  
} :0dfB&7  
} !fZLQc  
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