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http断点续传简单实现(java)

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/* MnP+L'|  
**SiteFileFetch.java Dqc2;>  
*/ \ cdns;  
package NetFox; G8.nKoHv7x  
import java.io.*; -6xh  
import java.net.*; |zJ2ZE|  
/@1pm/>ZaN  
AYAbq}'Yt  
public class SiteFileFetch extends Thread { 4+Jf!ovS=  
1/v#Z#3[  
V0G[f}tm'  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3pe1"maP  
long[] nStartPos; //开始位置 p/HGI)'  
long[] nEndPos; //结束位置 3U'l'H,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 iikMz|:7U  
long nFileLength; //文件长度 q7pe\~q  
boolean bFirst = true; //是否第一次取文件 M[C)b\  
boolean bStop = false; //停止标志 <b?$-Rx  
File tmpFile; //文件下载的临时信息 x->+w Jm@s  
DataOutputStream output; //输出到文件的输出流 }tQ^ch;Q  
_:%i6c*"  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ]!uId#OH  
public SiteFileFetch(SiteInfoBean bean) throws IOException C%|m[,Gx  
{ }lP`3e  
siteInfoBean = bean; BZ(DP_}&D  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "y60YYn-#J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^I{/j 'b&  
if(tmpFile.exists ()) X%T%N;P  
{ W^pf 1I8[  
bFirst = false; n7|,b- <  
read_nPos(); VI-6t"l  
} dl(!{tZ#  
else qC B{dp/  
{ XRTiC #6  
nStartPos = new long[bean.getNSplitter()]; C#B|^A_  
nEndPos = new long[bean.getNSplitter()]; R\-]$\1D  
} *-S?bv,T'  
TkVqv v  
:%h|i&B  
e@1A_q@.  
} A1*\ \[  
HM#|&_gV  
!;K zR&  
public void run() O Q$C#:?  
{ Yy;BJ_  
//获得文件长度 S%e)br}  
//分割文件 5?0~7^de  
//实例FileSplitterFetch }D-jTZlC  
//启动FileSplitterFetch线程 '.jYu7   
//等待子线程返回 dK4w$~j{k  
try{ lq mr`\@)  
if(bFirst) .#Z"Sj  
{ _T_} k:&X  
nFileLength = getFileSize(); ght3#  
if(nFileLength == -1) y8Rq2jI;(e  
{ csA-<}S5]b  
System.err.println("File Length is not known!"); @1i<=r  
} Ro;I%j  
else if(nFileLength == -2) mW~*GD~r  
{ @<&u;8y-Cn  
System.err.println("File is not access!"); o$Y#C{wC%  
} ErgWsAw-  
else sLWVgD  
{ HA[7)T N1E  
for(int i=0;i<nStartPos.length;i++) < FY%QB)h  
{ [,{Nu EI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4K 8(H9(  
} *U$%mZS]1  
for(int i=0;i<nEndPos.length-1;i++) fe8hgTP|  
{ FNw]DJ]  
nEndPos = nStartPos[i+1]; z|t2;j[  
}  M%g2UP  
nEndPos[nEndPos.length-1] = nFileLength; X3~` ~J  
} B4 5#-V  
} Ug384RzHN  
?<S fhjU  
QMy1!:Z&!  
//启动子线程 [7NO !^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; QKhGEW~G  
for(int i=0;i<nStartPos.length;i++) /,~g"y.;,  
{ h lSav?V_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @( 0O9L F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4dm0:, G  
nStartPos,nEndPos,i); ~,Yd.?.TI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IfT: 9 &  
fileSplitterFetch.start(); /x4L,UJ= P  
} p 16+(m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +DO<M1uE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \#IKirf?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", c|Z6p{)V  
nEndPos = " + nFileLength); MTq/  
// fileSplitterFetch[nPos.length-1].start();  d^zuo  
l%p,m [  
m77 !i>V)  
//等待子线程结束 G:@1.H`  
//int count = 0; m#-&<=  
//是否结束while循环 ddbQFAQQQ  
boolean breakWhile = false; T%;NW|mH&  
z.+%{_pe  
jp1e3 Cg  
while(!bStop) 6!N2B[9  
{ A8o)^T(vJ  
write_nPos(); i g .  
Utility.sleep(500); P s<k2  
breakWhile = true; 5X9Lh_p  
 Pa?{}A  
fsWIz1K  
for(int i=0;i<nStartPos.length;i++) IVa6?f6H_  
{  ;]bW  
if(!fileSplitterFetch.bDownOver) kB%.i%9\\  
{ _g-0"a{-  
breakWhile = false; gVy`||z  
break; eKo=g|D  
} Z3=N= xY]  
} 6urU[t1  
if(breakWhile) h0HK~S#xBv  
break; G}LV"0?  
C\OZs%]At  
9XhH*tBn7(  
//count++; iXWB  
//if(count>4) G]{^.5  
// siteStop(); ggm'9|  
} ruyQ}b:zS  
e,Y<$kPV  
C\vOxBAB  
System.err.println("文件下载结束!"); /{[p?7x>  
} rl&.|;5uH;  
catch(Exception e){e.printStackTrace ();} zL3zvOhu}  
} $DtUTh3)  
SLUQFoz}  
8R-;cBT  
//获得文件长度 pf+VYZ#)  
public long getFileSize()  rvK%m_r  
{ -t>"s'kv  
int nFileLength = -1; #0\* 8 6  
try{ <G`1(,g  
URL url = new URL(siteInfoBean.getSSiteURL()); ^HtB!Xc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zSu,S4m_;  
httpConnection.setRequestProperty("User-Agent","NetFox"); )[r=(6?n  
{`T^&b k  
H SGz-  
int responseCode=httpConnection.getResponseCode(); x8~*+ j  
if(responseCode>=400) <`NsX 6t  
{ 3 `mtc@*  
processErrorCode(responseCode); TIR Is1  
return -2; //-2 represent access is error !IB}&m  
} 7s!rer>  
& 9 c^9<F  
=dQ/^C_hj  
String sHeader; 9?~6{!m_9  
I0=L_&`)  
P=\Hi.]%  
for(int i=1;;i++)  Y(2Z<d  
{ 3(vm'r&5n>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); yF%e)6  
//Utility.log(in.readLine()); KrHKM3<  
sHeader=httpConnection.getHeaderFieldKey(i); !c-MC|  
if(sHeader!=null) 0vBQzM Q  
{ hY !>>  
if(sHeader.equals("Content-Length")) t~nW&]E  
{ V@TA~'$|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); z"QXPIXPk  
break; yLK %lP  
} &0"*.:J9  
} &^uaoB0  
else G;ZN>8NB  
break; [McqwU/Q  
} a" T+CA  
} &-JIXVd*R  
catch(IOException e){e.printStackTrace ();} -S&9"=v  
catch(Exception e){e.printStackTrace ();} a1u4v/Qu9  
[z+YX s!N  
^tWSu?9  
Utility.log(nFileLength); 6d2e WS  
*.+F]-  
i[{*(Y$L  
return nFileLength;  >;%QW  
} lA;^c)  
lN{>.q@V`r  
+aPe)U<t  
//保存下载信息(文件指针位置) N'$P( bx  
private void write_nPos() 5MZv!N   
{ UvB\kIH  
try{ ]#rV]As  
output = new DataOutputStream(new FileOutputStream(tmpFile)); E}a.qM'  
output.writeInt(nStartPos.length); B4+c3M\$V  
for(int i=0;i<nStartPos.length;i++) pv&iJ7RN  
{ _bg Zl  
// output.writeLong(nPos); jVN=_Y}\  
output.writeLong(fileSplitterFetch.nStartPos); d(R8^v/L  
output.writeLong(fileSplitterFetch.nEndPos); -vk/z+-^!  
} GK6CnSV8d  
output.close(); UX.rzYM&T  
} )1R[X!KQ7  
catch(IOException e){e.printStackTrace ();} Tyb'p9  
catch(Exception e){e.printStackTrace ();} 0Q8iX)  
} g}K/ba'  
,1lW`Krx  
'&K' 0qG  
//读取保存的下载信息(文件指针位置) !W0JT#0  
private void read_nPos() 7.g,&s%q  
{ WX_g  
try{ #UI`+2w  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;E5XH"L\  
int nCount = input.readInt(); =?wDQ:  
nStartPos = new long[nCount]; ) hoVB  
nEndPos = new long[nCount]; h^`@%g9 S  
for(int i=0;i<nStartPos.length;i++) MBKF8b'k  
{ kApDD[ N  
nStartPos = input.readLong(); 8oRq3"  
nEndPos = input.readLong(); '"rm66  
} q D=b+\F  
input.close(); DW:\6k  
} eoQt87VCU  
catch(IOException e){e.printStackTrace ();} |Zp') JiS  
catch(Exception e){e.printStackTrace ();} P *PJ  
} Sz')1<  
'.S02=/  
xcQ^y}JN  
private void processErrorCode(int nErrorCode) -;qK_x  
{ h<PS<  
System.err.println("Error Code : " + nErrorCode); sE|8a  
} @ptrF pSL  
/~fu,2=7  
V|HO*HiB3  
//停止文件下载 a[sdYZ  
public void siteStop() p?P.BU\CR  
{ R3)ccom  
bStop = true; ,+gtr.  
for(int i=0;i<nStartPos.length;i++) vMn$lT@  
fileSplitterFetch.splitterStop(); EUH9R8)  
]rg-=Y k  
\Ov~ t  
} <pS#wTsN4%  
} bmKvvq  
//负责部分文件的抓取 ]_|%!/_  
**FileSplitterFetch.java O(.eHZ=  
*/ ^U,C])n  
package NetFox; rfSEL 57'  
9Q\B1Q  
WUQa2$.  
import java.io.*; 9]tW;?  
import java.net.*; QAY:H@Gt:  
dI=&gz  
Z7e"4w A  
public class FileSplitterFetch extends Thread { d+ $:u  
$!z.[GL  
MD,BGO?C  
String sURL; //File URL YX3NZW2i  
long nStartPos; //File Snippet Start Position 07ppq?,y  
long nEndPos; //File Snippet End Position r(n>N0:0Ls  
int nThreadID; //Thread's ID h_\W7xt  
boolean bDownOver = false; //Downing is over XZ(<Mo\v  
boolean bStop = false; //Stop identical Gs04)KJm<  
FileAccessI fileAccessI = null; //File Access interface k<N5*k8M  
RcO.1@2  
@|'9nPern  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g^i\7'  
{ < 5ULu(b&$  
this.sURL = sURL; "#f5jH  
this.nStartPos = nStart; L}g#h+GP[  
this.nEndPos = nEnd; !)}z{,Jx  
nThreadID = id; .&>3nu  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 dWhqu68_  
} 2G3Hi;q18  
wg:\$_Og  
@x *,fk  
public void run() 6_tl_O7  
{ r.=.,R  
while(nStartPos < nEndPos && !bStop) I0^oaccM  
{ Upg8t'%{op  
sY]pszjT  
y4&x`|tv  
try{ aan(69=jz  
URL url = new URL(sURL); 9p4SxMMO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *Rc?rMF!  
httpConnection.setRequestProperty("User-Agent","NetFox"); uY3#,  
String sProperty = "bytes="+nStartPos+"-"; YelF)Na  
httpConnection.setRequestProperty("RANGE",sProperty); Pt6d5EIG  
Utility.log(sProperty); <v\x<ul6  
N5xI;UV9'  
'68#7Hs.  
InputStream input = httpConnection.getInputStream(); |H 5$VSw  
//logResponseHead(httpConnection); '3E25BsL  
`)BZk[64  
kpQN>XV#  
byte[] b = new byte[1024]; a%/x  
int nRead; {OS[0LB  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'BVI^H4  
{ 5T'v iG}%  
nStartPos += fileAccessI.write(b,0,nRead); b%VZPKA;  
//if(nThreadID == 1) ,}I m^~5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C MGDg}  
} PevT`\>  
WO^]bR  
vsYbR3O  
Utility.log("Thread " + nThreadID + " is over!"); _m%Ab3iT~  
bDownOver = true; 9.6ni1a'  
//nPos = fileAccessI.write (b,0,nRead); )2:U]d%pk  
} 6/Z_r0^O  
catch(Exception e){e.printStackTrace ();} Scmew  
} /-=h|A#Kh  
} V.ae 5@;  
HisH\z/i5)  
Enp;-wG:-  
//打印回应的头信息 7--E$ !9O,  
public void logResponseHead(HttpURLConnection con) +.*=Fn22  
{ )R"UX:Q>  
for(int i=1;;i++) zzT4+wy`  
{ &m TYMpA  
String header=con.getHeaderFieldKey(i); F9q!Upr_+  
if(header!=null) LftGA7uGJ)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); zq|NltK  
Utility.log(header+" : "+con.getHeaderField(header));  ]l  
else SUsdX[byb  
break; _0Y?(}  
} #aKUD  
} @CC 6 `D  
i> {0h3Y  
e :@PI(P!  
public void splitterStop() jRW@$ <mG  
{ \+C0Rv^^  
bStop = true; J d,9<m $  
} shVEAT'`  
|HwEwL+  
7DeBeY  
} # `@jVX0  
+.xK`_[M  
Lu4>C2{  
/* $3eoZ1q'U-  
**FileAccess.java VpED9l]y  
*//文件访问(定位,写) [ -R[rF  
package NetFox; `SS[[FT$>  
import java.io.*; >U]KPL[%  
TA~ZN^xI  
FY/F}C,o  
public class FileAccessI implements Serializable{ G P`sOPr  
7(<r4{1?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _k(&<1i  
RandomAccessFile oSavedFile; ]?Q<lMG  
long nPos; *mW2vJ/B  
vxrqUjK7  
Mh}vr%0;)  
public FileAccessI() throws IOException _93:_L  
{ 7~L_>7 ;  
this("",0); -NA2+].  
} O5*3 qJp  
$A T kCO  
[|(=15;  
public FileAccessI(String sName,long nPos) throws IOException #E_<}o  
{ 0*AXd=)"*  
oSavedFile = new RandomAccessFile(sName,"rw"); 9 {IDw   
this.nPos = nPos; q&LCMnv"P  
oSavedFile.seek(nPos); ylQ9Su>o  
} CKC5S^Mx  
cV4Y= &  
^szi[Cj  
public synchronized int write(byte[] b,int nStart,int nLen) P5lk3Zg '  
{ Iq 0ew  
int n = -1; 1*trtb4F  
try{ g3(LDqB'.  
oSavedFile.write(b,nStart,nLen); ^^*Ia'9   
n = nLen; vXG?8Q  
} Xu|2@?l9  
catch(IOException e) *dsI>4%m  
{ XaMsIyhI  
e.printStackTrace (); SU jo%3R  
} (?"z!dgc  
B_XX)y%V  
6wZ)GLW[  
return n; =RQI5 nHdw  
} $\PU Y8  
\(r$f!`  
; {v2s;  
}  #J  
f|~X}R  
b|\dHi2F T  
/* Mu6DT p~k  
**SiteInfoBean.java -]QP#_   
*/ er3`ITp:dp  
package NetFox; <*o V-A  
//%#?JJV  
6-+ wfrN2  
public class SiteInfoBean { D/hq~- g  
m!]J{OGG:  
QH?sx k2  
private String sSiteURL; //Site's URL V~do6[(  
private String sFilePath; //Saved File's Path dAy\IfZX=  
private String sFileName; //Saved File's Name `oM'H+  
private int nSplitter; //Count of Splited Downloading File Rgl cd  
XC O8A\  
:@-.whj  
public SiteInfoBean() <-,y0Y'  
{//nSplitter的缺省值为5 q4,/RZhzh  
//default value of nSplitter is 5 M4% 3a j  
this("","","",5); ImbA2Gcs  
} c:<a"$  
7OS i2  
):y^g:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ab]Q1kD  
{ $9:  @M.  
sSiteURL= sURL; ew]G@66  
sFilePath = sPath; @Bn4ZF B@  
sFileName = sName; 'pB?  
this.nSplitter = nSpiltter; h0I5zQZm  
5".bM8o  
GK[9IF#_>  
} |nGv:= H@  
0G2Y_A&e**  
i'\-Y]?[  
public String getSSiteURL() u7j,Vc'~  
{ ]q4(%Q  
return sSiteURL; Kf_xKW)^  
} LXPO@2QF  
iSg0X8J)  
?e,:x ]\L  
public void setSSiteURL(String value) Wu(^k25  
{ eKZS_Qd  
sSiteURL = value; ;zV<63tW  
} t*H|*L#YR  
C ,|9VH  
zQ<;3+*  
public String getSFilePath() 4jZB%tH  
{ 5HE5$S  
return sFilePath; ,KU%"{6  
} fNfa.0 s  
dnQ6Ras  
6NHP/bj<1V  
public void setSFilePath(String value) MUGoW;}v )  
{ oe0YxSauL  
sFilePath = value; O'{kNr{u  
} ,np|KoG|M  
B692Mn  
po,U e>n/  
public String getSFileName() iHK.hs;  
{ n&zEYCSI  
return sFileName; WWH<s%C  
} `%"x'B`mM  
}xi?vAaTl  
Gf:dN_e6.  
public void setSFileName(String value) 5\w*W6y  
{ 78~/1-  
sFileName = value; c 3o3i  
} I,HtW),  
SJc~E$5<  
!`1m.  
public int getNSplitter() O:pg+o&  
{ 2oRwDg&7|  
return nSplitter; z!18Jh  
} 9=}[~V n  
`h'=F(v(}  
~TeOl|!lE+  
public void setNSplitter(int nCount) 'mTY56Yq  
{ \ym^~ Q|  
nSplitter = nCount; MX7Ix{  
} \Q1&w2mw  
} q9{)nU  
!!)$?R;1  
?%Tx% dB  
/* MPy>< J  
**Utility.java `Syfl^9B  
*/ 4z26a  
package NetFox; a?8)47)  
$Bl51Vj N  
R5(([C1  
public class Utility { ,Z _@]D@  
3S2Alx!6  
#7}M\\$M  
public Utility() u%E8&T8,  
{ U1pE2o-  
p@uHzu7  
b4bd^nrqV  
} ?Tu=-ppw  
N-knhA  
//线程睡眠 " zD9R4\X.  
public static void sleep(int nSecond) SK^(7Ws~0  
{ R8eBIJ/@_  
try{ Dq$1 j%4Y  
Thread.sleep(nSecond); Y~A I2HS  
} Az8ZA~Op=  
catch(Exception e) QV:> x#=V  
{ SE@TY32T  
e.printStackTrace (); OdY9g2y#m  
} 3o/f, }_  
} R){O]<+  
(w5cp!qW9J  
//日志 %N&W_.F6  
public static void log(String sMsg) i8-Y,&>V  
{ ~>lqEa  
System.err.println(sMsg); ilHf5$  
} l&e$:=;8  
i20y\V os?  
bHE.EBZ  
public static void log(int sMsg) ruB D ^-  
{ ]&q<O0^'  
System.err.println(sMsg); nXoDI1<[  
} CMOyK^(e  
} $qdynKK  
Yk|.UuXT  
hhZ%{lqL  
/* X#JUorGp  
**TestMethod.java {"{]S12N  
*/ ~wv$uL8y  
package NetFox; $ B&Zn Z?  
~&qvS  
NW`.7'aWT  
public class TestMethod { DwGM+)!  
#G F.M,O/h  
Uuu2wz3O0  
public TestMethod() bo\Ah/.  
{ ///xx/weblogic60b2_win.exe w?|qKO  
try{ Pvi2j&W84  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Y)pop :y t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); uyB2   
SiteFileFetch fileFetch = new SiteFileFetch(bean); _LC*_LT_  
fileFetch.start(); 37a1O>A  
} fd>{ UyU  
catch(Exception e){e.printStackTrace ();} GF% /q:9  
\OFmd!Cz  
!o_eK\p  
} Q*ELMib  
i.)n#@M2  
iz`>'wpC  
public static void main(String[] args) :"!Z9l\@  
{ YF-E1`+?<  
new TestMethod(); 63Gq5dF  
} Um4zI>  
} .-tR <{ g  
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