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http断点续传简单实现(java)

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/* #F2DEo^0  
**SiteFileFetch.java pY&dw4V  
*/ -U?%A:,a|  
package NetFox; Br&&#  
import java.io.*; 9F6dKPN:  
import java.net.*; zb02\xvf  
&jQqlQ j  
a|[f%T<<  
public class SiteFileFetch extends Thread { 3u^wK  
qe(C>qjMbG  
XFl&(I4tB  
SiteInfoBean siteInfoBean = null; //文件信息Bean :?m"kh ~  
long[] nStartPos; //开始位置 C=U4z|Ym  
long[] nEndPos; //结束位置 9f5~hBlo  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1&7?f  
long nFileLength; //文件长度 O:RN4/17  
boolean bFirst = true; //是否第一次取文件 ) =x4+)9  
boolean bStop = false; //停止标志 589fr"Ma,6  
File tmpFile; //文件下载的临时信息 [fb9;,x`  
DataOutputStream output; //输出到文件的输出流 O#C0~U]dDW  
m39.j:BG5  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 2Dvq3VbiO"  
public SiteFileFetch(SiteInfoBean bean) throws IOException O&~ @ior  
{ nmE H/a  
siteInfoBean = bean; QQS "K g  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yv>uzb`N  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); i.?rom  
if(tmpFile.exists ()) _4#7 ?p  
{ DAORfFG74  
bFirst = false; u(? U[pe[  
read_nPos(); bJR\d0Z  
} GkU$Z @  
else Zp6VH  
{ eWD!/yr|  
nStartPos = new long[bean.getNSplitter()]; /l3Oi@\  
nEndPos = new long[bean.getNSplitter()]; p} eO  
} "[7'i<,AI  
\VW":+  
qf<o"B|_9  
'.S02=/  
} {Dy,|}7s  
Az#kE.8b*A  
-;qK_x  
public void run() p-rQ'e  
{ [C~N#S[]  
//获得文件长度 Nt?=0X|M  
//分割文件 r;H#cMj  
//实例FileSplitterFetch `022gHYv  
//启动FileSplitterFetch线程 _,UYbD\[J}  
//等待子线程返回 ,nPnH1vb  
try{ n-qle5sj  
if(bFirst) -y?ve od#  
{ 0QrRG$<4X  
nFileLength = getFileSize(); R3)ccom  
if(nFileLength == -1) AxTFV ot  
{ ,kYX|8SO  
System.err.println("File Length is not known!"); bu \(KR$s  
} ^"vmIC.h  
else if(nFileLength == -2) -qpM 6t  
{ '%*hs8s  
System.err.println("File is not access!"); <veypLi"R  
} HTMo.hr  
else \Ov~ t  
{ .N\t3\9}  
for(int i=0;i<nStartPos.length;i++) 7X> @r"9<  
{ X`eX+9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gf4Hq&Rf  
} qvhG ^b0h  
for(int i=0;i<nEndPos.length-1;i++) Ep')@7^n  
{ bun_R-  
nEndPos = nStartPos[i+1]; /6\uBy"Xt  
} ?G]yU  
nEndPos[nEndPos.length-1] = nFileLength; #,})N*7  
} ]2iIk=r$  
} JPj/+f  
%.\+j,G7  
\X]I: 0^j  
//启动子线程 p#r qe<Ua  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >!o!rs  
for(int i=0;i<nStartPos.length;i++) O]F(vHK\   
{ +x4*T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4ISIg\:c*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [kgCB7.V  
nStartPos,nEndPos,i); H&k&mRi  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,MHF  
fileSplitterFetch.start(); o`'4EVw*  
} I\j-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w&]$!g4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `7V1 F.\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >^<;;8Xh  
nEndPos = " + nFileLength); #Wb4*  
// fileSplitterFetch[nPos.length-1].start(); ~52'iI)Mw  
>:FmAey  
v"Ryg]^_  
//等待子线程结束 \]\GDpu[  
//int count = 0; !Ow M-t  
//是否结束while循环 X;vU z  
boolean breakWhile = false; 6vJ S"+ <  
[+}0K{(O=  
XJq]l6a:  
while(!bStop) 4`RZ&w;1H2  
{ -ntQqHs  
write_nPos(); vJx( lU`Y  
Utility.sleep(500); (gcy3BX;  
breakWhile = true; {\LLiU}MJC  
?\X9Ei  
mU||(;I  
for(int i=0;i<nStartPos.length;i++) f&] !;)  
{ M$6; &T  
if(!fileSplitterFetch.bDownOver) B LZ<"npn  
{  _Vc4F_  
breakWhile = false; g(Oor6Pp  
break; ;MlPP)*k  
} b!"FM/ %  
} !)}z{,Jx  
if(breakWhile) k@[[vj|W  
break; p2+K-/}ApP  
i.-2 w6  
CWd &  
//count++; O%&N6U  
//if(count>4) $"0`2C  
// siteStop(); 1$m{)Io2(  
} 2) 2:KX  
UvqnNA  
Zl]@;*u  
System.err.println("文件下载结束!"); 6_tl_O7  
} F2)KAIl  
catch(Exception e){e.printStackTrace ();} qB`%+<)C  
} -|=)  
-`t9@1P> =  
sdgI ,  
//获得文件长度 Az>r}*F Gr  
public long getFileSize() Mdu\ci)lr  
{ ,. <c|5R  
int nFileLength = -1; BcQw-<veu  
try{ jpMMnEVj6P  
URL url = new URL(siteInfoBean.getSSiteURL()); 7+6I~&x!Lz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7WmY:g#s  
httpConnection.setRequestProperty("User-Agent","NetFox"); s]D1s%Mx  
+p]@b  
'S=eW_ 0/  
int responseCode=httpConnection.getResponseCode(); 6&2{V? W3  
if(responseCode>=400) _C'VC#Sy  
{ ]/[@.   
processErrorCode(responseCode); /}CAd  
return -2; //-2 represent access is error *ck'vV'@  
} XuU>.T$]c  
.n?i' 8  
D@ @"w+  
String sHeader; J10&iCr{r*  
iqsR]mab  
mQK3YoC)  
for(int i=1;;i++) ,E+\SBQS_  
{ C]na4yE 8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); FEV Ya#S  
//Utility.log(in.readLine()); lr -+|>M)  
sHeader=httpConnection.getHeaderFieldKey(i);  (8 /&  
if(sHeader!=null) `bd9N !K  
{ PevT`\>  
if(sHeader.equals("Content-Length")) VZ9`Kbu  
{ VQ+G.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _m%Ab3iT~  
break; 9.6ni1a'  
} x Y}.mP  
} gN<J0c)  
else Scmew  
break; ,z+n@sUR:  
} #210 Yp#  
} ^Q!A4 qOQ  
catch(IOException e){e.printStackTrace ();} &u (pBr8B  
catch(Exception e){e.printStackTrace ();} &nY#G HB  
O}6*9Xy  
oS_YQOoD  
Utility.log(nFileLength); @?t+O'&  
&.Yu%=}  
#X?E#^6?E  
return nFileLength; ~ D/1U)kt  
} b~TTz`HZ  
A[:(#iR5-E  
~cfvL*~5  
//保存下载信息(文件指针位置) \GGyz{i  
private void write_nPos() SUsdX[byb  
{ _0Y?(}  
try{ #aKUD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S*WLb/R2  
output.writeInt(nStartPos.length); x3nUKQtk:8  
for(int i=0;i<nStartPos.length;i++) 81)i>]  
{ (>*L-&-  
// output.writeLong(nPos); &uf|Le4  
output.writeLong(fileSplitterFetch.nStartPos); =}SLQdT  
output.writeLong(fileSplitterFetch.nEndPos); Hig.` P  
} g}*p(Tp9:  
output.close(); )k4&S{=  
} iN5[x{^t  
catch(IOException e){e.printStackTrace ();} uME_/S uO  
catch(Exception e){e.printStackTrace ();} Z07n>|WF-  
} KJt6d`ZN  
(:}}p}u  
xb&,9Lxd|  
//读取保存的下载信息(文件指针位置) 5BM6Pnle  
private void read_nPos() mdcsL~R  
{ J{n A ?[  
try{ (/!zHq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !d95gq<=>  
int nCount = input.readInt(); @q{.shqo  
nStartPos = new long[nCount]; nu[["f~  
nEndPos = new long[nCount]; GB)< 5I  
for(int i=0;i<nStartPos.length;i++) w)/~Gn676  
{ y%<CkgZS  
nStartPos = input.readLong(); NA#,q 8  
nEndPos = input.readLong(); ZRFHs>0  
} :fnK`RnaQ  
input.close(); }8`>n4  
} *mW2vJ/B  
catch(IOException e){e.printStackTrace ();} vxrqUjK7  
catch(Exception e){e.printStackTrace ();} 0sF|Y%N  
} LQ||7>{eX  
gYmO4/c,  
[?2,(X0yh1  
private void processErrorCode(int nErrorCode) KfQR(e9n   
{ +Y>oNX1KN  
System.err.println("Error Code : " + nErrorCode); ]y"=/Nu-Ja  
} U~oGg$  
[Y^h)k{-$  
}gd'pgN"t  
//停止文件下载 KNOVb=# f_  
public void siteStop() #jPn7  
{ caV DV  
bStop = true; cV4Y= &  
for(int i=0;i<nStartPos.length;i++) ^RYq !l$  
fileSplitterFetch.splitterStop(); P4 #j;k4P  
KD- -w(4  
`A8ErfA  
} sR)jZpmC(  
} 9d!mGnl  
//负责部分文件的抓取 nt%p@e!,  
**FileSplitterFetch.java Hv%$6,/*v  
*/ V$dhiP z  
package NetFox; Epm8S}6K  
#IU^(W  
B_XX)y%V  
import java.io.*; 6wZ)GLW[  
import java.net.*; =RQI5 nHdw  
$\PU Y8  
\(r$f!`  
public class FileSplitterFetch extends Thread { F#.ph?W  
'@HCwEuz  
*<X*)A{C  
String sURL; //File URL |n~,{=  
long nStartPos; //File Snippet Start Position j@{dsS: 6  
long nEndPos; //File Snippet End Position .-Dc%ap]  
int nThreadID; //Thread's ID al7D3J  
boolean bDownOver = false; //Downing is over >qd=lm <,  
boolean bStop = false; //Stop identical {P )O#  
FileAccessI fileAccessI = null; //File Access interface xT!<x({  
QH?sx k2  
Bi>]s%zp  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s5)y %, E  
{ ,,lR\!>8  
this.sURL = sURL; "CZv5)  
this.nStartPos = nStart; M; YJpi  
this.nEndPos = nEnd; }^^c/w_  
nThreadID = id; flOXV   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _z9~\N/@[  
} ^1_CS*  
[\  &2&  
]0W64cuT  
public void run() j-ob7(v)*]  
{ $xjfW/k?M  
while(nStartPos < nEndPos && !bStop) ]ZNFrpq  
{ Q8$;##hzt  
{uJ"%  
F_4Et  
try{ E0+~c1P-  
URL url = new URL(sURL); W{~ y< `D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s^Xs*T@~h  
httpConnection.setRequestProperty("User-Agent","NetFox"); YGRb|P-  
String sProperty = "bytes="+nStartPos+"-"; q$Ms7 `a  
httpConnection.setRequestProperty("RANGE",sProperty); 0f_A"K  
Utility.log(sProperty); kO$n0y5e  
ab]Q1kD  
hFxT@I~  
InputStream input = httpConnection.getInputStream(); <`wOy [e  
//logResponseHead(httpConnection); @a,=ApS"  
G2-0r.f  
m!=5Q S3Z  
byte[] b = new byte[1024]; y9w,Su2  
int nRead; }w8yYI  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zL'S5'<F|  
{ N>1d]DrQR  
nStartPos += fileAccessI.write(b,0,nRead); ef/43+F^x  
//if(nThreadID == 1) >Psq" Xj  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a2/Mf   
} zS h9`F  
*zW]IQ'A  
Ex skd}  
Utility.log("Thread " + nThreadID + " is over!"); .L]5,#2([  
bDownOver = true; [(&aVHUj  
//nPos = fileAccessI.write (b,0,nRead); qk(bA/+e  
} !!w(`kmn1  
catch(Exception e){e.printStackTrace ();} 9vSKIq  
} /XU=l0u  
} bW=3X-)  
g yhy0  
dczSW ]%  
//打印回应的头信息 ]Tg@wMgI  
public void logResponseHead(HttpURLConnection con) 2 )3oX  
{ ,t:P  
for(int i=1;;i++) Ge7B%p8  
{ W1Ye+vg/s  
String header=con.getHeaderFieldKey(i); =E^/gc%X  
if(header!=null) I5`>XfO)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Wh~,?}laj  
Utility.log(header+" : "+con.getHeaderField(header)); o wb+,Gk(  
else -Q&@P3x  
break; S4-jFD)U  
} 0rm(i*Q  
} o[i*i<jv-  
5%}!z~8Y4  
`(=?k[48  
public void splitterStop() F^S]7{  
{ 69apTx  
bStop = true; ck3+A/ !z  
} 'GiN^Y9dcc  
.w'b%M  
-=5~-72~  
} 6NHP/bj<1V  
a'. 7)f[g}  
\fuz`fK:  
/* 2)T;N`tNw  
**FileAccess.java l-S0Gn/'X  
*//文件访问(定位,写) ~*<`PDO?  
package NetFox; 9Oo`4  
import java.io.*; GlRjbNW?Q  
'cQ,;y  
lyyf&?2  
public class FileAccessI implements Serializable{ \7pEn  
0C  K  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *c&OAL]  
RandomAccessFile oSavedFile; LZ.Xcy  
long nPos; A1`6+8}o;b  
lNtxM"G&  
1i_%1Oip  
public FileAccessI() throws IOException 3la`S$c  
{ V{w &RJ  
this("",0); )Q>Ao.  
} iA[o;D#  
@+Sr~:K  
UUb0[oy  
public FileAccessI(String sName,long nPos) throws IOException |5X59! JL  
{ xXa4t4gR  
oSavedFile = new RandomAccessFile(sName,"rw"); "* N#-=MJF  
this.nPos = nPos; b{{ H@LTW  
oSavedFile.seek(nPos); 5 6.JB BZZ  
} P1B=fgT  
>VQLC&u(  
svb7-.!  
public synchronized int write(byte[] b,int nStart,int nLen) u86PTp+  
{ NGkxg:  
int n = -1; =&qH%S6  
try{ >5"e<mwD7d  
oSavedFile.write(b,nStart,nLen); +"bi]^\z  
n = nLen; Cc,V ]  
} kE8s])Z,+  
catch(IOException e) UK1)U)*+  
{ -3azA7tzz  
e.printStackTrace (); /!A"[Tyt  
} $!y^t$u$@  
J YA>Q&  
4 2DMmwB   
return n; u/-EVCHr y  
} _nEVmz!zg  
;134$7!Y  
)pT5"{  
} ;aX?K/  
\%.oi@A  
jYFmL_{  
/* t u{~:Z(  
**SiteInfoBean.java ?!/8~'xA6  
*/ =Y6W Qf  
package NetFox; '5[(QM5Gi&  
47 Bg[  
+PI}$c-|`  
public class SiteInfoBean { OVU)t]  
dv3u<XM~  
W*#5Sk  
private String sSiteURL; //Site's URL Ip=QtNW3\  
private String sFilePath; //Saved File's Path _z{9V7n4  
private String sFileName; //Saved File's Name q(^iT~}  
private int nSplitter; //Count of Splited Downloading File _KxR~k^  
wvxz:~M  
9p3~WA/M@  
public SiteInfoBean() g1"Z pD  
{//nSplitter的缺省值为5 zwJ&K;"y(  
//default value of nSplitter is 5 un -h%-e |  
this("","","",5); Ql l{;A  
} 5(hv|t/a  
v1X[/\;U  
T4"D&~3 3q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ak('4j!*}^  
{ [u2t1^#Ol  
sSiteURL= sURL; NCG;`B`i  
sFilePath = sPath; 92A9gY  
sFileName = sName; 8wOscL f:  
this.nSplitter = nSpiltter; bHE.EBZ  
Y)1J8kq_  
qGEp 6b H  
} a%si:_  
ty rP[y  
-WF((s;<#  
public String getSSiteURL() /V/NL#(R  
{ |3!)  
return sSiteURL; ~LV]cX2J(  
} >dm9 YfQ  
Q1x&Zm1v  
Lw_|o[I}  
public void setSSiteURL(String value) " M?dU^U^  
{ udA@9a^;  
sSiteURL = value; 4 l-Urn Z  
} Tq?Ai_  
q Tdwi?j_  
ZAN~TG<n  
public String getSFilePath() >(.|oT\Tb  
{ =#y;J(>~|  
return sFilePath; PQSmBTs.  
} KA?%1s(kJ  
LPu *Lkx  
QSa#}vCp*  
public void setSFilePath(String value) R2-F@_  
{ 3 e1-w$z&S  
sFilePath = value; Uuu2wz3O0  
} :H m'o}  
Xo~q}(ze^  
oe 6-F)+  
public String getSFileName() QkD ~  
{ 0!0e$!8l  
return sFileName; /(hTk&  
} ,f:K)^yD  
!3k-' ),z&  
{4Kvr4)4  
public void setSFileName(String value) )lS04|s  
{ `Ng Q>KV!  
sFileName = value; _LC*_LT_  
} v G\J8s  
5=|h~/.k  
7I"~a<f0X`  
public int getNSplitter() 5o>`7(t`  
{ Z.Z;p/4F  
return nSplitter; 6LGl]jHf  
} !ae?EJm"  
,&S0/j  
fK+E5~vQ  
public void setNSplitter(int nCount) %,02i@Fc  
{ `:V'E>B  
nSplitter = nCount; :dULsl$Nz  
} 6?<lS.s  
} Y!_c/!Tx  
O$m &!J  
GAYn*'<  
/* *#Ia8^z=p  
**Utility.java ZlMT) ~fM&  
*/ n~|?)EL  
package NetFox; 2 A!*8w  
;NdH]a {  
}k%6X@  
public class Utility { <Y?Z&rNb  
mR@d4(:J?  
-#T%*  
public Utility() d!R+-Fp  
{ ZZo<0kDk  
jF}kV%E  
g%S/)R,,ct  
} 7:uz{xPK6  
a4~B  
//线程睡眠 1Xm>nF~  
public static void sleep(int nSecond) 0'pB7^y  
{ ]7W!f 2@  
try{ DAWF =p]  
Thread.sleep(nSecond); q 9xA.*  
} ^#Q-?O  
catch(Exception e) V^[&4  
{ (W:@v&p  
e.printStackTrace (); $RYGAh  
} }l$zZ>.\H  
} r.#r!.6 q  
r1%{\<   
//日志 bs)wxU`Q*  
public static void log(String sMsg) Tt~[hC h  
{ dB4ifeT]  
System.err.println(sMsg); -A w]b} #v  
} rmkBp_i{|  
~<VxtcEBz  
9Q s5e  
public static void log(int sMsg) Bx|W#:3e  
{ ,Owk;MV@  
System.err.println(sMsg); OH2IO  
} BX[ IWP\%  
} 1%B9xLq  
N}B&(dJ  
#9DJk,SP  
/* hui #<2{  
**TestMethod.java n)q8y0if  
*/ 0:[A4S`X  
package NetFox; L QV@]z&  
#1'q'f:7 &  
(b#M4ho*f  
public class TestMethod { }'x)e  
Z!|r>  
N^oP,^+U  
public TestMethod() HLPRTta.  
{ ///xx/weblogic60b2_win.exe %pjeA[-m#  
try{ IL.bwt pQD  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Kj @<$ChZw  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "*X\'LPs=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); g{}<ptx]  
fileFetch.start(); 8el6z2  
} E<3xv;v8r  
catch(Exception e){e.printStackTrace ();} `0]N#G T  
GZrN,M  
hfY/)-60o  
} Fn`Zw:vp6  
h]&  
Qv ~@  
public static void main(String[] args) -9{N7H  
{ /fT"WaTEK  
new TestMethod(); 7!jb  
} |Ol29C$@|  
} ^|Fy!kp  
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