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http断点续传简单实现(java)

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/* cj/FqU"  
**SiteFileFetch.java tt>=Vt '  
*/ ]7{-HuQ8>}  
package NetFox; \>-%OcYlM  
import java.io.*; U z6XQskX  
import java.net.*; mCx6$jz  
O k~\  
zHCz[jlrMq  
public class SiteFileFetch extends Thread { U=bZy,FT$  
7e&%R4{b  
v<Ux+-  
SiteInfoBean siteInfoBean = null; //文件信息Bean [t`QV2um  
long[] nStartPos; //开始位置 _/!IjB:(70  
long[] nEndPos; //结束位置 /=qn1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 u5FlT3hY.  
long nFileLength; //文件长度 = 8%+$vX  
boolean bFirst = true; //是否第一次取文件 bx<7@  
boolean bStop = false; //停止标志 /P|jHK|{  
File tmpFile; //文件下载的临时信息 FeFH_  
DataOutputStream output; //输出到文件的输出流 #VEHyz6P  
I2'UC) 0  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) _sCpyu  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2xd G&}$fa  
{ P1ab2D  
siteInfoBean = bean; ]Z\.Vx  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); R#Bdfmld q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;=6~,k)  
if(tmpFile.exists ()) 3J}bI {3  
{ up7]Yy;o=  
bFirst = false; L1k_AC1.M  
read_nPos(); <&rvv4*H  
} YvK8;<k@-?  
else ?79ABm a  
{ Tce2]"^;  
nStartPos = new long[bean.getNSplitter()]; `D%bZ%25c  
nEndPos = new long[bean.getNSplitter()]; lU.@! rGbw  
} 6^.<5SJ}  
HIi 5kv]}|  
L%JmdY;  
xGeRoW(X  
} Y75,{1\l0  
RW|3d<Fj  
Y m|zM1qc  
public void run() >%.6n:\rG  
{ PQ|kE`'  
//获得文件长度 }ya9 +?I  
//分割文件 pRj1b^F5y  
//实例FileSplitterFetch D[)g-_3f6<  
//启动FileSplitterFetch线程 Dw^d!%Ala  
//等待子线程返回 ]|[oL6"  
try{ ;Z"6ve4  
if(bFirst) ]J C}il_b  
{ MI@id  
nFileLength = getFileSize(); ?j8F5(HF?  
if(nFileLength == -1) B@l/'$G  
{ ;%AK< RT  
System.err.println("File Length is not known!"); xS`>[8?3<T  
} g Xvuv^  
else if(nFileLength == -2) kfBVF%90  
{ V Z;ASA?;  
System.err.println("File is not access!"); -[4Xg!apO  
} R1FBH:Iu  
else _{6QvD3kg.  
{ X/TuiKe  
for(int i=0;i<nStartPos.length;i++) [(Pm\o  
{ @twClk.s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (yCF pb  
} #|34(ML  
for(int i=0;i<nEndPos.length-1;i++) ;z>)&F  
{ hX]vZR&R  
nEndPos = nStartPos[i+1]; (<pc4#B@*  
} =$IjN v(?  
nEndPos[nEndPos.length-1] = nFileLength; 40oRO0p  
} -Vk+zEht  
} nqt;Ge M  
&V[m{.  
2*5Z| 3aX  
//启动子线程 ~w'M8(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t+5JIQY>  
for(int i=0;i<nStartPos.length;i++) RJ1 Q.o  
{ -1~bWRYq  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Mjrl KI}f/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $z]gy]F  
nStartPos,nEndPos,i); Cw`v\ 9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E3y"  
fileSplitterFetch.start(); g&H6~ +\  
} `6b!W0$ -  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }r6SV%]:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); HP2]b?C  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #m6 eG&a  
nEndPos = " + nFileLength); #n 7uw  
// fileSplitterFetch[nPos.length-1].start(); "EQ-`b=I4  
X6/k `J  
E/9 U0  
//等待子线程结束 _ pM&Ya  
//int count = 0; C$xU!9K[+  
//是否结束while循环 M& GA:`  
boolean breakWhile = false; cTFyF)  
=m=`|Bn  
!12W(4S5  
while(!bStop) H~1*`m  
{ -#H>kbs  
write_nPos(); ^ S'}RZ*>  
Utility.sleep(500); Ft>Abj,6  
breakWhile = true; $6T*\(;T@A  
`itaQGLD  
oW(p (>  
for(int i=0;i<nStartPos.length;i++) yw2^kk93|  
{ c-!rJHL`  
if(!fileSplitterFetch.bDownOver) T%Vii*?M  
{ #vYdP#nWb  
breakWhile = false; Nrva?W_i  
break; Iw8;",e2  
} tB4- of3+  
} a5:Q%F<!  
if(breakWhile) %lAJ]$m  
break; Zg%U4m:  
l~wx8 ,?G  
P}y}IR{6  
//count++; ^_r8R__S:  
//if(count>4) eXWiTi@  
// siteStop(); _) 2fXG!  
} l=[<gPE  
=9GL;z:R+  
0Np }O=>  
System.err.println("文件下载结束!"); 9`+c<j4/B  
} a1B_w#?8  
catch(Exception e){e.printStackTrace ();} &96I4su  
} -kxNJ Gc?  
qdrk.~_  
1Dg\\aUk  
//获得文件长度 6+A<_r`#Q  
public long getFileSize() 8*I43Jtlf,  
{ ?h"+q8&  
int nFileLength = -1; Xz&Hfs"/J  
try{ &!vJ3:  
URL url = new URL(siteInfoBean.getSSiteURL()); kN >%y&cK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c%r?tKG6  
httpConnection.setRequestProperty("User-Agent","NetFox"); &xMR{:  
pj G6v(zK  
8E"Ik ~  
int responseCode=httpConnection.getResponseCode(); UMuqdLaT9  
if(responseCode>=400) Gvw4ot/  
{ ~mx me6"v  
processErrorCode(responseCode); 7OG=LF*V-  
return -2; //-2 represent access is error aR ao\Wp|  
} p#) u2^  
V|ax(tHv  
2cr~/,YY  
String sHeader; ^[Cpu_]D  
R_:47.qq  
UP}Y s*  
for(int i=1;;i++) <Vm+Lt9  
{ 2?58=i%b  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); tzJdUZJ  
//Utility.log(in.readLine()); \,i9m9;y  
sHeader=httpConnection.getHeaderFieldKey(i); aG}ju;  
if(sHeader!=null) : I28Zi*  
{ ao#{N=mn  
if(sHeader.equals("Content-Length")) >xws  
{ gEbe6!; q3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); a H'iW)  
break; QpwOrxI}  
} t/LQ|/xo  
} fGHYs  
else _?kjIF  
break; &WE|9  
} vF0#]  
} 4=td}%  
catch(IOException e){e.printStackTrace ();} I4:4)V?  
catch(Exception e){e.printStackTrace ();} hC?:XVt  
^&buX_nlO  
u~7mH  
Utility.log(nFileLength); G < Z)y#  
xQ9P'ru  
M?Tb9c?`  
return nFileLength; T_|%n F-+  
} '8K5=|!J  
"i_I<?aGB  
~+}w>jIm{|  
//保存下载信息(文件指针位置) l5QH8eNwME  
private void write_nPos() e3,TY.,Ay  
{ x1</%y5ev  
try{ ?pn<lW8d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); L|.q19b*  
output.writeInt(nStartPos.length); W~(@*H  
for(int i=0;i<nStartPos.length;i++) @^]wT_r  
{ _^;+_6&[  
// output.writeLong(nPos); l{ja2brX  
output.writeLong(fileSplitterFetch.nStartPos); Osncl5PD)  
output.writeLong(fileSplitterFetch.nEndPos); u :AKp<'  
} H6%QM}t  
output.close(); G66sP w  
} huFT_z_;;  
catch(IOException e){e.printStackTrace ();} @q:v?AO  
catch(Exception e){e.printStackTrace ();} L[o;@+32  
} {\z&`yD@  
u UXj  
gsFyZ  
//读取保存的下载信息(文件指针位置) 5Z"IM8?  
private void read_nPos() ,PC'xrEo  
{ gv)F`uRWA  
try{ 3SI:su  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); FN jT?*  
int nCount = input.readInt(); ^*JpdmVhu  
nStartPos = new long[nCount]; nF$n[:  
nEndPos = new long[nCount]; !lxs1!:  
for(int i=0;i<nStartPos.length;i++) )c|S)iJ7=z  
{ 7{F(NJUO1  
nStartPos = input.readLong(); *FhD%><  
nEndPos = input.readLong(); Axp#8  
} Z3jh-{0  
input.close(); lO=+V 6  
} !R p  
catch(IOException e){e.printStackTrace ();} }?[^q  
catch(Exception e){e.printStackTrace ();} s}"5uDfn1F  
} )Dn~e#  
bz5",8Mn  
E.~;  
private void processErrorCode(int nErrorCode) ~q0g7?}&  
{ ">pW:apl%  
System.err.println("Error Code : " + nErrorCode); 4cZig\mE;  
} &G63ReW7 @  
vn oI.;H,  
yLv jfP1  
//停止文件下载 _D{zB1d\0  
public void siteStop() ;/tZsE{  
{ Bfh[C]yy  
bStop = true; iV+'p->/  
for(int i=0;i<nStartPos.length;i++) J6m`XC  
fileSplitterFetch.splitterStop(); jC_7cAsl  
VjZ_L_U}  
z3F ^OU   
} #bRr|`  
} x0t&hY>P!  
//负责部分文件的抓取 W40GW  
**FileSplitterFetch.java +a'QHtg  
*/ ;=rMIi  
package NetFox; ,$;g'z!N  
*7`N^e  
aFkxR\x 6%  
import java.io.*; XD1 x*#  
import java.net.*; _-NS-E  
sU7>q}!  
$`nKq4Y   
public class FileSplitterFetch extends Thread { 79.J`}#  
{HgW9N(  
iU)-YFO  
String sURL; //File URL = mn jIp  
long nStartPos; //File Snippet Start Position 3F%Q q7v  
long nEndPos; //File Snippet End Position $}[Tj0+:  
int nThreadID; //Thread's ID $Cu/!GA4.>  
boolean bDownOver = false; //Downing is over ^RN1?dXA  
boolean bStop = false; //Stop identical jgiP2k[Xom  
FileAccessI fileAccessI = null; //File Access interface 4SG22$7W  
)9,*s !)9  
E)(`Z0  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Dl862$_Q  
{ #=WDJ T:  
this.sURL = sURL; Q]*YIb~D  
this.nStartPos = nStart; NJYx.TL  
this.nEndPos = nEnd; lYd#pNN  
nThreadID = id; ^q"wd?((h  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?e |'I"  
} M mg#Vy~  
o3H+.u$  
Z2chv,SqCJ  
public void run() l<<G". ?  
{ 0/.#V*KM  
while(nStartPos < nEndPos && !bStop) B0c}5V  
{ lY}mrb  
,2>:h"^  
mRCgKW<  
try{ p71% -nV  
URL url = new URL(sURL); RJs_ S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XEqg%f  
httpConnection.setRequestProperty("User-Agent","NetFox"); X.0/F6U  
String sProperty = "bytes="+nStartPos+"-"; 1A23G$D  
httpConnection.setRequestProperty("RANGE",sProperty); H+zn:j@~L  
Utility.log(sProperty); $"{V],:T |  
x7e  
+DKrX  
InputStream input = httpConnection.getInputStream(); &QOob)  
//logResponseHead(httpConnection); 0:G@a&Lr  
T4 SByX9  
tYfhKJzGC  
byte[] b = new byte[1024]; /3%]Ggwe  
int nRead; -b@E@uAX /  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +ZXGT  
{ y_"GMw  
nStartPos += fileAccessI.write(b,0,nRead); >ge-yK 1  
//if(nThreadID == 1) 8O{]ML  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qn@Qd9Sf  
} *DkA$Eu3u  
kt1f2cj  
nVG\*#*]|  
Utility.log("Thread " + nThreadID + " is over!"); @n(=#Q3  
bDownOver = true; ]_BG"IR!..  
//nPos = fileAccessI.write (b,0,nRead); f.jAJ; N>  
} af{;4Cr  
catch(Exception e){e.printStackTrace ();} va8:QHdU  
} [ur/`   
}  CjQ_oNI  
QBto$!})  
q1dYiG.-Z  
//打印回应的头信息 n2#uH  
public void logResponseHead(HttpURLConnection con) @=wAk5[IN  
{ !^axO  
for(int i=1;;i++) 8Z3+S)6  
{ D~f.)kkC4  
String header=con.getHeaderFieldKey(i); 8gC(N3/E"  
if(header!=null) C,PCU<q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d c&Qi_W  
Utility.log(header+" : "+con.getHeaderField(header)); x6DH0*[.  
else 1rPeh{SZ  
break; mA^>Y_:  
} 6\o.wq  
} YSrFHVq  
z5'VsK:  
l"*>>/U k  
public void splitterStop() uaDU+y wL  
{ R:.7 c(s  
bStop = true; /v!H{Zw=c  
} L0&!Qct  
C)C;U&Qd  
}Xc|Z.6  
} E"G. _<3J8  
D 0n2r  
D[-Ct  
/* D[tGbk  
**FileAccess.java }p- %~ Y  
*//文件访问(定位,写) B!tt e )  
package NetFox; A`N;vq,  
import java.io.*; [\.>BK  
H>7!+&M  
fGe{7p6XV*  
public class FileAccessI implements Serializable{ (u'/tNGS  
0~S<}N  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pH~JPNng  
RandomAccessFile oSavedFile; ',&MYm\  
long nPos; ;q^YDZ'  
=:0(&NCRq  
VmT5? i  
public FileAccessI() throws IOException ih;TQ!c+b  
{ uBMNkN8  
this("",0); O~Fk0}-  
} QV 'y6m\  
ut,"[+ J  
kt:%]ZZL  
public FileAccessI(String sName,long nPos) throws IOException T a[74;VO  
{ T6,lk1S'=  
oSavedFile = new RandomAccessFile(sName,"rw"); (Z5#;rgem  
this.nPos = nPos;  Uh8ieb  
oSavedFile.seek(nPos); "nefRz%j+  
} e^an` </{  
[}Iq-sz;0  
F>Oh)VL,Ev  
public synchronized int write(byte[] b,int nStart,int nLen) X5yhS  
{ 3gh^a;uC  
int n = -1; #P@r[VZ{6  
try{ "|%fA E  
oSavedFile.write(b,nStart,nLen); [aC9vEso!  
n = nLen; ~zX5}U<R  
} '[E_7$d  
catch(IOException e) !58JK f  
{ 4%7*tVG  
e.printStackTrace (); n 3]y$wK  
} =>J#_Pprn  
< KA@A}  
?C{N0?[P-  
return n; ?n+\T'f!  
} `ouzeu9}  
OY#_0p)i  
Ye6O!,R  
} f5-={lUlIS  
`!8Z"xD  
]*h}sn=  
/* 19t*THgq  
**SiteInfoBean.java QMY4%uyY!  
*/ *)1z-rH`  
package NetFox; 3"n8B6  
J_@4J7  
hH/ O2  
public class SiteInfoBean { T1&H!  
~] 2R+  
hzb|:  
private String sSiteURL; //Site's URL ;p ('cwU%  
private String sFilePath; //Saved File's Path %R>S"  
private String sFileName; //Saved File's Name {@%(0d{n}  
private int nSplitter; //Count of Splited Downloading File nE;gM1I  
mg(56)  
^'4uTbxP_!  
public SiteInfoBean() WU\bJ}  
{//nSplitter的缺省值为5 &/F[kAy  
//default value of nSplitter is 5 8|GpfW3p 2  
this("","","",5); $ZO<8|bW  
} J.l%H U  
bn35f<+  
?g4|EV-56  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Rp*t"HSaAW  
{ eHe /w9`$R  
sSiteURL= sURL; BaAb4{  
sFilePath = sPath; Hrnql  
sFileName = sName; \[EWxu  
this.nSplitter = nSpiltter; \k_3IP?o=  
uLljM{ I  
R <\Yg3m8  
} NG UGN~p  
y3]"H(  
Q{hOn]"  
public String getSSiteURL() MlE~ gCD  
{ ;%alZ  
return sSiteURL; sLp LY1X  
} Y j\yO(o/  
2kq@*}ys  
63Yu05'  
public void setSSiteURL(String value) !\O,dq  
{ U&$]?3?  
sSiteURL = value; =Gz>ZWF  
} "Cj#bUw  
2z# @:Q  
*+4iBpyiB  
public String getSFilePath() Bqlc+d:  
{ NV4W2thYo  
return sFilePath;  89=JC[c  
} }zxh:"#K  
Jjh!/pWZ4  
/ i2-h  
public void setSFilePath(String value) F5[ITK]A4  
{ +STzG /9#  
sFilePath = value; B^~Bv!tHWr  
} 3#9r4;&  
p!QneeA`&X  
k]9>V@C  
public String getSFileName() /~cL L  
{ G$9|aaf`1#  
return sFileName;  Rha3  
} pbxcsA\  
|0R%!v(,  
6Ok=q:;  
public void setSFileName(String value) V?dK*8s  
{ H6S vU  
sFileName = value; 7h&`BS  
} V^/^OR4k  
p<fgUVR  
<O)X89dFM  
public int getNSplitter() wK`ieHmp  
{ NV(4wlh)y  
return nSplitter; ::R00gd  
} 3=|2Gs?ut  
_JIUds5  
n9fA!Wic  
public void setNSplitter(int nCount) gIM'bA<~  
{ 7RC096 ?}  
nSplitter = nCount; }cK~=@7tK  
} z<vO#  
} \ jXN*A  
O0(Q0Ko  
.C;_4jE  
/* zpr@!76  
**Utility.java {!eANm'  
*/ <eFAI}=s  
package NetFox; DcR}pQ(e  
l(w vQO  
3?Eoj95w!  
public class Utility { A r7mH4M  
$EGRaps{j>  
V;hwAQbF  
public Utility() ._MAHBx+G  
{ j5h 6u,^:  
SM#S/|.]  
hn\Q6f+  
} [aM'  
.i&ZT}v3  
//线程睡眠 u !3]RGJ  
public static void sleep(int nSecond) =6:L+ V  
{ 'uf\.F  
try{ 'tu@`7*  
Thread.sleep(nSecond); !MJe+.  
} Cq*}b4^;  
catch(Exception e)  I`'a'  
{ H1%[\X?=  
e.printStackTrace (); uQu/(5  
} ^L-w(r62<  
} ^2C /!Y<  
w0j/\XN 2s  
//日志 T<f\*1~^  
public static void log(String sMsg) !H1tBg]5  
{ 8hKP  
System.err.println(sMsg); RE>ks[  
} JYg% ~tW'  
LZc$:<J<6  
?)' 2l6  
public static void log(int sMsg) I!@s6tG  
{ K4k~r!&OU  
System.err.println(sMsg); z{@R.'BD  
} h^A3 0f_x  
} hH1lgc  
*m$PH"  
sCF40AoY&  
/* R>d@tr  
**TestMethod.java 2sqm7th  
*/ ?AnjD8i  
package NetFox; f{igW?Ho  
^}o7*   
\+iu@C  
public class TestMethod { Gg9VS&VI  
/}w#Jk4pD  
2f|6z- Z  
public TestMethod() 3$c(M99r  
{ ///xx/weblogic60b2_win.exe SLtSqG7~  
try{ s !#HZK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Re*|$r#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `l>93A  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8M^wuRn  
fileFetch.start(); 0%s3Mp6H  
} )RwBg8  
catch(Exception e){e.printStackTrace ();} wfxOx$]z K  
rQ    
c[VrC+e m  
} g ?afX1Sg  
M[aT2A  
Ys-Keyg  
public static void main(String[] args) 8FzHNG  
{ 5M%,N-P^  
new TestMethod(); )n7|?@5U  
} 'h-3V8m^e  
} d5DP^u  
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