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http断点续传简单实现(java)

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/* Zpc R   
**SiteFileFetch.java n1n->l*HGP  
*/ R@zl?>+  
package NetFox; xNDX(_U>\  
import java.io.*; f/+UD-@%m  
import java.net.*; OwRH :l  
7HfA{.|m  
L *",4!  
public class SiteFileFetch extends Thread { bit@Kv1<C  
Tk1U  
'PiQ|Nnb|  
SiteInfoBean siteInfoBean = null; //文件信息Bean bDK%vx!_  
long[] nStartPos; //开始位置 4'EC(NR7N  
long[] nEndPos; //结束位置 kq +`.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2smQD8t  
long nFileLength; //文件长度 k6.<zs0  
boolean bFirst = true; //是否第一次取文件 BO]}E:C9  
boolean bStop = false; //停止标志 e+416 ~X v  
File tmpFile; //文件下载的临时信息 X'[93 C|K  
DataOutputStream output; //输出到文件的输出流 sX_6qKUH  
a(cZ]`s]*  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) JSO'. [N  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ujb7uho  
{ o m9zb&{tu  
siteInfoBean = bean; Ib V 7}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =?9z6=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); fu 0]BdM  
if(tmpFile.exists ()) !.\-l2f  
{ {jVEstP  
bFirst = false; j\SvfZ0"  
read_nPos(); \ct7~!qM  
} ;F3#AO4(  
else .]gY{_|x  
{ En&`m  
nStartPos = new long[bean.getNSplitter()]; |,ws3  
nEndPos = new long[bean.getNSplitter()]; yex4A)n9"'  
} R8"qDj  
H!6nIS9yxt  
2o5Pbdel  
~# ~XDcc  
} (Qf"|3R4  
Fh[Gq  
-%I 0Q  
public void run() cHr.7 w  
{ U_\3preF  
//获得文件长度 CEOD$nYc  
//分割文件 JY6&CL`C  
//实例FileSplitterFetch *(c><N  
//启动FileSplitterFetch线程 Cx,)$!1  
//等待子线程返回 ^j-w^)@T  
try{ w]-,X`  
if(bFirst) Fqr}zR)  
{  v7Q=  
nFileLength = getFileSize(); 6xfG`7Az  
if(nFileLength == -1) "V7 SB   
{ s01W_P.@R  
System.err.println("File Length is not known!"); T~Z7kc'  
} P%%[_6<%M  
else if(nFileLength == -2) 8AX+s\N  
{ Rq,ST:  
System.err.println("File is not access!"); RCCI}ovU  
} ccCe@1RI  
else 1ig#|v*+  
{ yKy07<Gr>  
for(int i=0;i<nStartPos.length;i++) uW@o,S0:  
{ Xj;\ROBH-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); f*uD9l%/  
} XwerQwO=  
for(int i=0;i<nEndPos.length-1;i++) )U$]J*LI  
{ Vy+UOV&v-  
nEndPos = nStartPos[i+1]; zLeId83>  
} (K"8kQLY  
nEndPos[nEndPos.length-1] = nFileLength; =5 zx]N1r  
} 6X1_NbC  
} ,sn/FT^; q  
+[2X@J  
rEWPVT  
//启动子线程 OI0tgkG  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; W5#5RK"uX  
for(int i=0;i<nStartPos.length;i++) ga#Yd}G^~3  
{ O7KR~d  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c"<bq}L7S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N=?! ~n9Q-  
nStartPos,nEndPos,i); fBZ\,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3aK/5)4|B  
fileSplitterFetch.start(); BAUo`el5  
} !uno!wUIYd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `;'fCO!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [>pqf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", HJV8P2f8`  
nEndPos = " + nFileLength); qrq9NPf  
// fileSplitterFetch[nPos.length-1].start(); P2Or|_z  
KR4vcI[4  
G\HU%J  
//等待子线程结束 r]0UF0#  
//int count = 0; [u=DAk?8  
//是否结束while循环 K9BoIHo  
boolean breakWhile = false; TAXl73j_CY  
~582'-=+  
0xNlO9b/  
while(!bStop) 'yq'J)  
{ I,0]> kx  
write_nPos(); &R'%OFi  
Utility.sleep(500); TLkJZ4}?Q  
breakWhile = true; /p&)bL  
>Za66<:  
qL\*rYe<  
for(int i=0;i<nStartPos.length;i++) GA8cA)]zOD  
{ Ul EP;  
if(!fileSplitterFetch.bDownOver) k*;2QED  
{ [H3~b=  
breakWhile = false; Q I.*6-(  
break; ,;_D~7L  
} jE&Onzc  
} -6()$cl}0  
if(breakWhile) E?& x5?  
break; bhFAt1h  
rI[Lg0S  
]:Q7Gys  
//count++; }PR^Dj.  
//if(count>4) K%p*:P  
// siteStop(); /&+6nOP  
} qM$~5uu  
Nr#Y]9nA  
HxVQeyOR  
System.err.println("文件下载结束!"); })l+-H"  
} yk5T"# '+  
catch(Exception e){e.printStackTrace ();} }UzO_&Z#6  
} <IF\;,.c  
jZ'y_  
<N{pMz  
//获得文件长度 iZ`1Dzxgk  
public long getFileSize() us.+nnd  
{ ~YuRi#CTD:  
int nFileLength = -1; |sw&sfH[FD  
try{ AR}M*sSh  
URL url = new URL(siteInfoBean.getSSiteURL()); `B`/8Cvg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :*2+t-  
httpConnection.setRequestProperty("User-Agent","NetFox"); F7(~v2|  
lRn6Zh  
v!;E1  
int responseCode=httpConnection.getResponseCode(); Yg;g!~   
if(responseCode>=400) %;.|?gR  
{ %5_eos&<^)  
processErrorCode(responseCode); ,u}n!quA  
return -2; //-2 represent access is error ==psPyLF@  
} ))n7.pB9/  
o(W|BD!  
@"~Mglgw  
String sHeader; %qzpt{'?<  
7eh|5e$@  
mf26AIlkQ  
for(int i=1;;i++) 5k`[a93T  
{ F_SkS?dB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !Xwp;P=  
//Utility.log(in.readLine()); @"}dbW<DV  
sHeader=httpConnection.getHeaderFieldKey(i); I +,D,Vg  
if(sHeader!=null) `p&ko$i2  
{ }lgqRg)F9[  
if(sHeader.equals("Content-Length")) 6(4o}Sv  
{ `>fN? He  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); JlsRP  
break; kWfNgu$xK  
} eiZv|?^0  
} auP:r  
else i3.8m=>  
break; bOCdf"!g  
} dXh@E 7  
} iSxxy1R  
catch(IOException e){e.printStackTrace ();} 'JEZ;9}  
catch(Exception e){e.printStackTrace ();} 4\q7.X+^  
_%s_w)  
B{ NKDkDH  
Utility.log(nFileLength); ,q#^ _/?  
]xfAdBi  
r*/Pyh  
return nFileLength; !oU$(,#9  
} !MB%  
&7 }!U  
OwP9=9};  
//保存下载信息(文件指针位置) vd-`?/,||  
private void write_nPos() k@5,6s:  
{ I}Z[F,}*J  
try{ -A9 !Y{Z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Y*``C):K%  
output.writeInt(nStartPos.length); wLD/#Hfi7  
for(int i=0;i<nStartPos.length;i++) ~(B\X?v  
{ p5C sw5  
// output.writeLong(nPos); Sv-}w$  
output.writeLong(fileSplitterFetch.nStartPos); w\Q3h`.  
output.writeLong(fileSplitterFetch.nEndPos); !^ 6x64r  
} qH6DZ|  
output.close(); tc@U_>{  
} q*A2>0O  
catch(IOException e){e.printStackTrace ();} Q8M&nf  
catch(Exception e){e.printStackTrace ();} nJ4h9`[>V  
} 4j!MjlG$  
.i/]1X*;r^  
(0W%Y Z!&  
//读取保存的下载信息(文件指针位置) i^uC4S~  
private void read_nPos()  zUqiz  
{ JRA.,tQc  
try{ _]tR1T5e  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .jr1<LE  
int nCount = input.readInt(); >qx~m>2|8]  
nStartPos = new long[nCount]; g\ @nA4  
nEndPos = new long[nCount]; kTex>1W;  
for(int i=0;i<nStartPos.length;i++) *6Rl[eXS  
{  ~u8}s4  
nStartPos = input.readLong(); aQN`C {nY  
nEndPos = input.readLong(); hzPx8sO  
} 5vY h~|  
input.close(); "h7-nwm  
} %>i7A?L  
catch(IOException e){e.printStackTrace ();} mo#4jtCE  
catch(Exception e){e.printStackTrace ();} e=Kv[R'(M  
} c6s(f  
5S$HDO&  
t2OXm  
private void processErrorCode(int nErrorCode) Rv q_Zsm  
{ N)  {  
System.err.println("Error Code : " + nErrorCode); ;lX:EU  
} {<~XwJ.  
$Miii`VS9  
6FSw_[)  
//停止文件下载 wXZ.D}d  
public void siteStop() vG\]xM'u  
{ w}NgFrL  
bStop = true; 30>TxL=&  
for(int i=0;i<nStartPos.length;i++) Eg-b5Z);  
fileSplitterFetch.splitterStop(); <4{@g]0RV  
'[Oi_gE.  
AXPUJ?V  
} u{H,i(mx?  
} 7L;yN..0  
//负责部分文件的抓取  e^&YQl  
**FileSplitterFetch.java um#;S;  
*/ (fh:q2E#  
package NetFox; NFLmM  
B[4y(Im  
$'9r=#EH  
import java.io.*; Z mi<Z  
import java.net.*; {yt]7^  
f`A  
r-N2*uYtu  
public class FileSplitterFetch extends Thread { lu(G3T8  
(P`{0^O"}  
]N=C%#ki!  
String sURL; //File URL .2xypL8(  
long nStartPos; //File Snippet Start Position Oku4EJFJ  
long nEndPos; //File Snippet End Position m3_e]v3{o  
int nThreadID; //Thread's ID P603P  
boolean bDownOver = false; //Downing is over >+vWtO 2  
boolean bStop = false; //Stop identical :1Fm~'  
FileAccessI fileAccessI = null; //File Access interface .[ 1A  
Q=PaTh   
7U.g4x|<  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  N%r}0  
{ 7=QV^G  
this.sURL = sURL; D<++6HN&#  
this.nStartPos = nStart; Mh+'f 93  
this.nEndPos = nEnd; >j`*-(`2fa  
nThreadID = id; 0^ E!P>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :WA o{|&  
} qZ\zsOnp  
"mPa >`?  
Go`omh b  
public void run() z(\H.P#  
{ oSa FmP  
while(nStartPos < nEndPos && !bStop) t_]UseP$RF  
{ CdaB.xk  
/mD KQ<  
(sqS(xIY  
try{ )&dhE^ O  
URL url = new URL(sURL); d}l^yln  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !+hX$_RT  
httpConnection.setRequestProperty("User-Agent","NetFox"); VpV w:Rh>  
String sProperty = "bytes="+nStartPos+"-"; ['R=@.  
httpConnection.setRequestProperty("RANGE",sProperty); 3l L:vD5(  
Utility.log(sProperty); M0]l!x#7  
"apv)xdW  
KG3*~G  
InputStream input = httpConnection.getInputStream(); TJ; v}HSo  
//logResponseHead(httpConnection); =dA T^e##  
}7.q[ ^oF  
EL}v>sC  
byte[] b = new byte[1024]; Tl%4L % bE  
int nRead; *|E@ 81s#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [qZ4+xF,,  
{ s}z,{Y$-t  
nStartPos += fileAccessI.write(b,0,nRead); X!2|_  
//if(nThreadID == 1) }SN'*w@E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <}mT[;:"  
} @tj0Ir v  
+] 5a(/m.~  
ZcWl{e4  
Utility.log("Thread " + nThreadID + " is over!"); Y}?@Pm drz  
bDownOver = true; E,6E-9  
//nPos = fileAccessI.write (b,0,nRead); epG;=\f}m`  
} R3@iN &  
catch(Exception e){e.printStackTrace ();} = oh6;Ojt  
} XdS<51 C  
} ~IqT >  
njq-iU  
X4k/7EA  
//打印回应的头信息 F_r eBPx  
public void logResponseHead(HttpURLConnection con) /uyQ>Y*-\Y  
{ ix#  
for(int i=1;;i++) D$mrnm4d  
{ l:|Fs=\  
String header=con.getHeaderFieldKey(i); -{7N]q)}  
if(header!=null) _:K}DU'6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =[jBOx&  
Utility.log(header+" : "+con.getHeaderField(header)); o>*{5>#k'  
else |1<Z3\+_/  
break; 3+$O#>  
} [`b{eLCFX]  
} VuBp$H(U  
 mPD'"  
MnS"M[y3  
public void splitterStop() @'rO=(-b  
{ % (.PRRI  
bStop = true; 3PEs$m9e  
} }GC{~ SZ4  
aLq;a  
\bsm#vY,  
} ibAA:I,d  
gU%GM  
LtU+w*Gj  
/* wS^-o  
**FileAccess.java v6n(<0:  
*//文件访问(定位,写) T*ic?!  
package NetFox; Bf}_ Jw-=  
import java.io.*; A+l"  
s-ou;S3s  
>mV""?r]  
public class FileAccessI implements Serializable{ gJ7$G3&oZg  
#RD%GLY  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;'Q{ ywr  
RandomAccessFile oSavedFile; (j /O=$mJ  
long nPos; p4Y 9$(X  
,-"]IR!,w  
C;ye%&g>  
public FileAccessI() throws IOException W9D)QIqbvW  
{ lm\u(3_ $  
this("",0); 19vD(KC<  
} Mzd}9x$'J  
:W&\})  
{h=Ai[|l4Q  
public FileAccessI(String sName,long nPos) throws IOException pZjFpd|  
{ [~o3S$C&7  
oSavedFile = new RandomAccessFile(sName,"rw"); -+=8&Wa  
this.nPos = nPos; Ygl!fC 4b  
oSavedFile.seek(nPos); {HU48v"W  
} gn%"dfm  
: L>d]Hn  
`otQ'e~+t  
public synchronized int write(byte[] b,int nStart,int nLen) *k}d@j,*"  
{ ~h/U ;Da  
int n = -1; UGMdWq  
try{ gkdjH8(2  
oSavedFile.write(b,nStart,nLen); o (zg_!P  
n = nLen; L}mhMxOTi  
} x9e 9$ww}  
catch(IOException e) vKC>t95  
{ d0^2<  
e.printStackTrace (); +x2xQ8#|~~  
} P:v y  
O+N-x8W{  
t]ZSo-  
return n; !jbjrzv9  
} T,fz/5w  
z|2liQrf+  
]3C8  
} V_pBM  
Vh8uE  
5-*]PAC  
/* 9wC; m:  
**SiteInfoBean.java i&$uG[&P  
*/ #o RUH8  
package NetFox; Sf8d|R@O  
+\%zy=  
xlLS`  
public class SiteInfoBean { rBf?kDt6l  
Ydx5kUJV<  
;k8}D*?8  
private String sSiteURL; //Site's URL MlZ`g,{  
private String sFilePath; //Saved File's Path cOQy|v`KD,  
private String sFileName; //Saved File's Name 9?8`" v  
private int nSplitter; //Count of Splited Downloading File 3^Zi/r  
?q P }=nJ  
D |o@(V  
public SiteInfoBean() %8Z,t+'  
{//nSplitter的缺省值为5 qHCs{ u  
//default value of nSplitter is 5 X3[!xMij  
this("","","",5); )R4<* /C:w  
} :m\KQ1sq  
u_B SWhiW  
hqPn~Tq  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) q*O KA5  
{ UVK"%kW#(  
sSiteURL= sURL; y#+o*(=fRE  
sFilePath = sPath; <B`V  
sFileName = sName; ShpnFuH  
this.nSplitter = nSpiltter; lI 1lP 1  
lNb\^b  
={^#E?  
} oK6lCGM5  
|BW,pT  
S2)S/ nf  
public String getSSiteURL() _LNPB$P  
{ 7;NV 1RV  
return sSiteURL; 2#3R]zIO  
} y`\Mhnj  
.a*$WGb  
1' m $_  
public void setSSiteURL(String value) 9f\8oJQ  
{ ^v-'=1ub?  
sSiteURL = value; 919g5f`  
} QGd- 9UEA]  
p0K;m%  
]aNnY?qW5  
public String getSFilePath() <Z' hZ  
{ lG9ARRy(=  
return sFilePath; b U NYTF{  
} rLxX^[Fp3  
_GqE'VX  
M-N2>i#  
public void setSFilePath(String value) ozLJ#eOE9  
{ fP58$pwu  
sFilePath = value; (, "E9.  
} $8k_M   
keskD  
NrcCUZ .:N  
public String getSFileName() rzDJH:W{2  
{ 4&e@>  
return sFileName; ?LI9F7n  
} p8l#=]\ ;  
L?x?+HPY.  
Z@!W? Ed  
public void setSFileName(String value) I&8m5F?$`  
{ I})t  
sFileName = value; C4]%pi  
} 2< Bv=B  
@88i/ Z_  
Ky#B'Bh}`g  
public int getNSplitter() t [hocl/6  
{ I!gj;a?R  
return nSplitter; 9 w1ONw8v  
} ?bAFYF0!I  
gqRTv_;  
T+RI8.#o  
public void setNSplitter(int nCount) '*u;:[73  
{ \_nmfTr!K  
nSplitter = nCount; y PYJc  
} ?4e6w  
} #Hi]&)p_  
@BUqQ9q:  
AijTT%  
/* $?AA"Nz  
**Utility.java A(OfG&!  
*/ uz3pc;0LPY  
package NetFox; d~-p;i  
*)1Vs'!-  
Wxau]uix  
public class Utility { ([b!$o<v  
D"4&9"CU  
\&&(ytL  
public Utility() ) Zo_6%  
{ 9,f<Nb(\  
!]+Z%ed`%  
5!jNL~M  
} 6F.7Ws <  
nDB 2>J  
//线程睡眠  ;c Co+(  
public static void sleep(int nSecond) aroVyUs3j  
{ 9<h]OXv  
try{ ds;cfj[  
Thread.sleep(nSecond); nVn|$ "r  
} UXPegK!  
catch(Exception e) Wk#h,p3  
{ E8_Le  
e.printStackTrace (); tQ/ #t<4D  
} kEhm'  
} ct4 [b|  
i4zV(  
//日志 Qy5Os?9"  
public static void log(String sMsg) D?yE$_3>c  
{ <o!&Kk9  
System.err.println(sMsg); _b_?9b-)D  
} ``|RO[+2  
dM s||&|&  
{{ *]bGko  
public static void log(int sMsg) X";Z Up  
{ !Nl.Vb  
System.err.println(sMsg); M*|VLOo=v  
} }"?nU4q;S  
} Zxc7nLKF~  
(s$u_aq 77  
? x"HX|n  
/* !@<@QG-  
**TestMethod.java [Z5[~gP3  
*/ %aH$Tb%`hc  
package NetFox; ] @)!:<+  
MziZN^(  
Np<&#s[dQ  
public class TestMethod { ur<eew@8@i  
H8$<HhuZM  
S1^nC tSF  
public TestMethod() /ggkb8<3  
{ ///xx/weblogic60b2_win.exe Bug}^t{M  
try{ YYE8/\+B.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Z@,PZ   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WVWS7N\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); n(1wdlEp  
fileFetch.start(); 3p3WDL7  
} {[,Wn:  
catch(Exception e){e.printStackTrace ();} Q:kVCm/;  
i&pJg1  
6b ]1d04hT  
} ZEj!jWP2m  
/MKNv'5&!%  
_+\:OB[Y  
public static void main(String[] args) ,9Z2cgXwJ  
{ nx-1*  
new TestMethod(); O~h94 B`  
} (D>y6r> r  
} XpgV09.EE  
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