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http断点续传简单实现(java)

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/* `i<;5s!rX  
**SiteFileFetch.java IX7<  
*/ QU2\gAM  
package NetFox; np}F [v  
import java.io.*; T9osueh4  
import java.net.*; !=;^Grv>  
}H&NR?Ax  
Tar tV3;`  
public class SiteFileFetch extends Thread { (`>RwooE  
hw:zak#j,  
559znM=  
SiteInfoBean siteInfoBean = null; //文件信息Bean -n?}L#4%8  
long[] nStartPos; //开始位置 R%Gh4y\nF  
long[] nEndPos; //结束位置 RXP0 4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (Eq0 |"cj  
long nFileLength; //文件长度 : |#Iw  
boolean bFirst = true; //是否第一次取文件 q+>J'UGb  
boolean bStop = false; //停止标志 )2C_6eR  
File tmpFile; //文件下载的临时信息 g>_lU vSE  
DataOutputStream output; //输出到文件的输出流 K, ae-#wgb  
0zCe|s.S&  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) k6_RJ8I  
public SiteFileFetch(SiteInfoBean bean) throws IOException HeZ! "^w  
{ 7hqa|  
siteInfoBean = bean; %3M(!X:[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #/Y t4n  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); AF g*  
if(tmpFile.exists ()) w4H3($ K  
{ y TfAS .  
bFirst = false; T]l_B2.  
read_nPos(); R?a)2jl  
} rj&  
else DBANq\  
{ br*L|s\P\9  
nStartPos = new long[bean.getNSplitter()]; JhRXfIK>{  
nEndPos = new long[bean.getNSplitter()]; )sWdN(E3  
} oM/(&"  
-yHVydu=  
RUC V!L  
*lRP ZN  
} 2cY7sE068  
TK<~ (Dk  
7^P!@o$v!  
public void run() B<i )je!  
{ 8  !]$ljg  
//获得文件长度 \Q7Nz2X  
//分割文件 {y0#(8-&  
//实例FileSplitterFetch p:U9#(v)  
//启动FileSplitterFetch线程 =PWh,lWS  
//等待子线程返回 Z;M]^?  
try{ :j)H;@[I  
if(bFirst) S^? @vj  
{ jFf2( AR  
nFileLength = getFileSize(); ( >zXapb2  
if(nFileLength == -1) qMD6LWJ  
{ *T' /5,rX2  
System.err.println("File Length is not known!"); z1XFc*5  
} kFZw"5hb  
else if(nFileLength == -2) C2NJrg4(  
{ 12n5{'H2%  
System.err.println("File is not access!"); p8o ~  
} jU |0!]  
else ; >Tko<  
{ gO_{(\w*  
for(int i=0;i<nStartPos.length;i++) 6"U&i9  
{ [hSE^ m  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Q]9H9?}N?  
} Ymkk"y.w  
for(int i=0;i<nEndPos.length-1;i++) 5<\&7P3y  
{ hG .>>  
nEndPos = nStartPos[i+1]; xjB2?:/2  
} _doX&*9u  
nEndPos[nEndPos.length-1] = nFileLength; dIgaw;Ch]  
} Vui5ZK  
} teH $hd-q  
6Ko[[?Lf[  
E5qh]z (  
//启动子线程 % \p:S)R  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]CsF} wr'z  
for(int i=0;i<nStartPos.length;i++) b3N>RPsHS  
{ =Bo(*%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Cy-q9uTm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), g N76  
nStartPos,nEndPos,i); Jy?s'tc  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w|!>>W6J  
fileSplitterFetch.start(); )_N|r$i\  
} 0j\?zt?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $o"S zy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #D~atgR  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >Vz Gx(7q  
nEndPos = " + nFileLength); (~}IoQp>  
// fileSplitterFetch[nPos.length-1].start(); >U.TkB  
|3`Sd;^;  
)/kkvI()l  
//等待子线程结束 F!OVx<  
//int count = 0; S'm&Ll2i@  
//是否结束while循环 <cm,U)j2  
boolean breakWhile = false; a]XQM$T$  
c+chwU0W  
Y^$^B,  
while(!bStop) -jy- KC  
{ .^j6  
write_nPos(); m-9{@kgAM?  
Utility.sleep(500); EEFM1asJf  
breakWhile = true; qXPjxTg{[  
(]7&][  
yk OJhd3  
for(int i=0;i<nStartPos.length;i++) Lsv[@Rl  
{ ]Tk3@jw+b  
if(!fileSplitterFetch.bDownOver) ?n<b:oO  
{ I:l<t*  
breakWhile = false; 2Pn  
break; Z ? `  
} 9SF2  
} yx?Z&9z <  
if(breakWhile) Lh.?G#EM  
break; 7.)e4  
A.tONPi  
Y-\/Y*;cd  
//count++; B@g 0QgA  
//if(count>4) 0 Y[LzLn  
// siteStop(); WBT/;),}:  
} R{Q*"sf  
1Q1NircJ  
,>%2`Z)  
System.err.println("文件下载结束!"); 1FCqkwq[  
} mOji\qia  
catch(Exception e){e.printStackTrace ();} 6vp\~J  
} 'F>eieO  
"]h4L  
ParOWs~W/  
//获得文件长度 6)63Yp(  
public long getFileSize() Ojqbj0E9  
{ *y +T(73  
int nFileLength = -1; 6\>S%S2:  
try{ P__JN\{9  
URL url = new URL(siteInfoBean.getSSiteURL()); [iVCorU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iq'hel  
httpConnection.setRequestProperty("User-Agent","NetFox");  pleLdGq  
xL8r'gV@  
6UK{0\0  
int responseCode=httpConnection.getResponseCode(); xG:eS:iT  
if(responseCode>=400) l_bvwo  
{ ~/Gx~P]  
processErrorCode(responseCode); =kvfe" N0e  
return -2; //-2 represent access is error eF+:w:\h  
} g-`HKoKe  
lnuf_;0  
bH4'j/3  
String sHeader; QHOA__?  
9qc<m'MZ  
8xs}neDg*  
for(int i=1;;i++) _GEt:=DAP#  
{ (T;4'c  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?/ xk  
//Utility.log(in.readLine()); +>3XJlZV  
sHeader=httpConnection.getHeaderFieldKey(i); |iN!V3#S  
if(sHeader!=null) k"_i7  
{ :lj1[q:Y>  
if(sHeader.equals("Content-Length")) '<! b}1w0  
{ IvuKpX>*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ny# ?^.1  
break; }  IJ  
} 9))E\U  
} ?d@3y<A,~  
else #ra"(/)  
break; (gN[<QL  
} *J^l r"%c  
} 7|4t;F!  
catch(IOException e){e.printStackTrace ();} ]7<}EG  
catch(Exception e){e.printStackTrace ();} e8T#ZWr*  
XaT9`L<  
)~/;Xl#b-  
Utility.log(nFileLength); n8W+q~sW%  
N-XOPwx'  
~)>O=nR  
return nFileLength; #oBMA  
} GIXxOea1  
1k-YeQNe  
TZ#(G  
//保存下载信息(文件指针位置) <T]BSQk  
private void write_nPos() Yq~$Q4  
{ j8Nl'"  
try{ nnr g^F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `/]Th&(5  
output.writeInt(nStartPos.length); Ky"]L~8$  
for(int i=0;i<nStartPos.length;i++) * V;L|c  
{ oU/CXz?H  
// output.writeLong(nPos); Vl=!^T}l+  
output.writeLong(fileSplitterFetch.nStartPos); b4NUx)%ln  
output.writeLong(fileSplitterFetch.nEndPos); b(^gv  
} "^sh:{  
output.close();  zxN,ys  
} <dzfD;  
catch(IOException e){e.printStackTrace ();} CeL`T:]r  
catch(Exception e){e.printStackTrace ();} tBR"sBiws  
} V>"nAh]}.  
;. jnRPo";  
80qSPitj  
//读取保存的下载信息(文件指针位置) yX%q7ex  
private void read_nPos() >q W_%  
{ c6 O1Z\M@\  
try{ dnRS$$9#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2R}9wDP  
int nCount = input.readInt(); `re9-HM  
nStartPos = new long[nCount]; *Uq1 q  
nEndPos = new long[nCount]; &T7|f!y  
for(int i=0;i<nStartPos.length;i++) =Xwr*FTr  
{ DH7B4P  
nStartPos = input.readLong(); " S8JHHx  
nEndPos = input.readLong(); k^A17Nf`2  
} 6T3uv,2  
input.close(); gz{~\0y  
} | %E\?-TK  
catch(IOException e){e.printStackTrace ();} }M3f ?Jv  
catch(Exception e){e.printStackTrace ();} .M Ni)+  
} S"t6 *fWr  
,&+"|,m  
Gyo[C98  
private void processErrorCode(int nErrorCode) Ql~9a [8T~  
{ oW0A8_|9  
System.err.println("Error Code : " + nErrorCode); |>w>}w`~  
} :exgdm;N  
sZ~q|}D-  
LW+a-i  
//停止文件下载 RM^3Snd=V  
public void siteStop() H{XbKLU  
{ E0F8FR'  
bStop = true; P''5A6#5  
for(int i=0;i<nStartPos.length;i++) :.;p Rz  
fileSplitterFetch.splitterStop(); 4J#F;#iA  
+y%"[6c|  
<d2?A}<  
} CcF$?07 i  
} ;rBd_  
//负责部分文件的抓取 ].E89_|O  
**FileSplitterFetch.java jZRf{  
*/ FG-v71!h#  
package NetFox; q_0So}  
I` `S%`h  
YH_mWN\Wu  
import java.io.*; w$ zX.;s  
import java.net.*; \0}!qG![AA  
kNC.^8ryz[  
{VB n@^'s  
public class FileSplitterFetch extends Thread { $-HP5Kj(k-  
F0 yvV6;  
jO` b&]0  
String sURL; //File URL ;3 N0)  
long nStartPos; //File Snippet Start Position 5m.{ayE  
long nEndPos; //File Snippet End Position [73 \jT  
int nThreadID; //Thread's ID ,r$k79TI  
boolean bDownOver = false; //Downing is over hxwo<wEg  
boolean bStop = false; //Stop identical KKrLF?rc  
FileAccessI fileAccessI = null; //File Access interface 2(SU# /,  
B =EI&+F+  
|rjHH<  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException rV yw1D  
{ uL\b*rI  
this.sURL = sURL; QNH-b9u>8  
this.nStartPos = nStart; 2 kP0//  
this.nEndPos = nEnd; & XS2q0-x  
nThreadID = id; }6Ut7J]a|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =H<I` J'  
} |E%i t?3M  
x,U '!F  
0 _!')+  
public void run() 2sezZeMV  
{ tHhau.!  
while(nStartPos < nEndPos && !bStop) s} I8:ufT  
{ W0zRV9"P  
pUGFQ."\  
W6e,S[J^FY  
try{ i~};5j(  
URL url = new URL(sURL); ]lX`[HX7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xz$-_NWW  
httpConnection.setRequestProperty("User-Agent","NetFox"); C:*=tD1  
String sProperty = "bytes="+nStartPos+"-"; %anY'GK   
httpConnection.setRequestProperty("RANGE",sProperty); fU6O:-  
Utility.log(sProperty); {Xw6]d  
3MmpB9l#H  
(D\7EH\9,]  
InputStream input = httpConnection.getInputStream(); q=EHB5!q  
//logResponseHead(httpConnection); >yZe1CP  
1*x;jO>Hk  
qjcPJ  
byte[] b = new byte[1024]; ~wtK(U  
int nRead; Z[ NO`!<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q)/V >QW  
{ P{bRRn4Z  
nStartPos += fileAccessI.write(b,0,nRead); #Nv^F  
//if(nThreadID == 1) 8 vp*U  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EZ"n3#/  
} qG6?k}\\  
tj' xjX  
*]7$/%.D  
Utility.log("Thread " + nThreadID + " is over!"); ~nVO%IxM4J  
bDownOver = true; B~CdY}UTsj  
//nPos = fileAccessI.write (b,0,nRead); rexNsKRK_  
} &H4Y`xV^=  
catch(Exception e){e.printStackTrace ();} #J Ay  
} /e:kBjysJ  
} <Jf[N=  
O)aWTI  
f@j)t%mh  
//打印回应的头信息 up@I,9C/  
public void logResponseHead(HttpURLConnection con) O x),jc[/  
{ JK/gq}c  
for(int i=1;;i++) {!L25  
{ NT0im%  
String header=con.getHeaderFieldKey(i); LmZ"_  
if(header!=null) $(r/N"6)O2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]aMeMhe-  
Utility.log(header+" : "+con.getHeaderField(header)); lz [s  
else {@&%Bq*&  
break; A<U9$"j9J  
} .N>Th/K8  
} E*Z# fa  
}T~ }W8H  
[S_qi,  
public void splitterStop() S]x\Asj;w  
{ `3e>JIl"0  
bStop = true; !qe:M]C'l  
} ]zATdfa  
V{{Xz:   
Bnfp_SM  
} YApm)O={  
TF %MO\!  
;{Nc9d  
/* |[W7&@hF  
**FileAccess.java ccY! OSae  
*//文件访问(定位,写) :Ldx^UO  
package NetFox; 0@tN3u?dx  
import java.io.*; v;o/M6GL5  
(3Dz'X  
J3z:U&%=  
public class FileAccessI implements Serializable{ \0fk^  
_'0C70  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 i}gsxq%  
RandomAccessFile oSavedFile; [vTk*#Cl4  
long nPos; )Y &RMYy  
g2%fla7r  
EM7Z g 65  
public FileAccessI() throws IOException ?p'DgL{  
{ $1uT`>%  
this("",0); ]99@Lf[^f  
} mlO\wn-F  
^N&@7s  
F #)@ c  
public FileAccessI(String sName,long nPos) throws IOException f;=<$Y>i  
{ <lgX=wx L  
oSavedFile = new RandomAccessFile(sName,"rw"); 1d 1 ~`B  
this.nPos = nPos; awl3|k/  
oSavedFile.seek(nPos); Bp-e< :  
} a7}O.NDf  
dCA! R"HD  
5ENEx  
public synchronized int write(byte[] b,int nStart,int nLen) *t300`x  
{ (>SucUU  
int n = -1; _P9*78  
try{ 7d^ ~.F  
oSavedFile.write(b,nStart,nLen); 2QgD<  
n = nLen; >0JC u^9  
} "i,ZG$S#E  
catch(IOException e) lkW5<s_  
{ tu's]3RE  
e.printStackTrace (); DJb9] ,=a  
} j@R"AP}  
s+E: 7T9P  
3<>DDY2bl  
return n; 8RT<?I^5  
} [P`<y#J3F  
H.< F6  
b(\Mi_J  
} V8rS~'{\  
&Qmb?{S0  
q1Ad"rm  
/* 2(f-0or(  
**SiteInfoBean.java / 5/m x  
*/ [)?yH3  
package NetFox; ft1V1 c  
aVZ/e^kk-  
S 3s6  
public class SiteInfoBean { ji C2B  
" u)e,gu  
48Jt1^  
private String sSiteURL; //Site's URL =fJ  /6  
private String sFilePath; //Saved File's Path &$ fyY:<\  
private String sFileName; //Saved File's Name WWTRB +1>  
private int nSplitter; //Count of Splited Downloading File z.^_;Vql_  
Fj46~#ZZ  
1\J9QZX0  
public SiteInfoBean() |rI;OvZ\  
{//nSplitter的缺省值为5 29zMs9oKPP  
//default value of nSplitter is 5 [#(',~lN7  
this("","","",5); ux~=}{tz  
} tn;{r  
2BiFP||  
P(!%Pp  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Uy|Tu~  
{ ;Sfe.ky @6  
sSiteURL= sURL; OC)=KV@KE  
sFilePath = sPath; sR^b_/ElxT  
sFileName = sName; h.wffk,  
this.nSplitter = nSpiltter; g_J QW(_  
jOd+LXPJ  
v\E6N2.S  
} J50n E~  
4 !m'9  
_St ":9'uU  
public String getSSiteURL() Q5A,9ovNZ  
{ [930=rF*  
return sSiteURL; KWM.e1(  
} U'u_'5 {  
$)~:H-  
SYh>FF"  
public void setSSiteURL(String value) uzT+,  
{ %`~+^{Wp  
sSiteURL = value; BLAF{vVaf  
} K{,'%|  
z]KJ4  
\4>w17qng  
public String getSFilePath() YkE_7r(1  
{ x!7r7|iV  
return sFilePath; L2_[M'  
} u8t|!pMF8  
|!/+ T^u  
s}-j.jzB{  
public void setSFilePath(String value) C/QrkTi=  
{ ( P=WKZMPN  
sFilePath = value; `,]_r 4~ ~  
} ]')y(_{  
+XSe;xk;rD  
;Qi!~VsP;  
public String getSFileName() p1hF.  
{ =qbN?a/?2  
return sFileName; VFMn"bYOB  
} 'p78^4'PL  
)Gk?x$pY@  
T 1R~^x1  
public void setSFileName(String value) ~]].i~EV(  
{ _CTg")0o  
sFileName = value; ng~LCffpY  
} q/Vl>t  
^)GaVL^"5  
on"ENT  
public int getNSplitter() aOd|;Z  
{ KJv%t_4'F  
return nSplitter; !@wUAR Q  
} {$5g29  
Ux{0)"fj  
3)L#V .  
public void setNSplitter(int nCount) =CD.pw)B1  
{ rqnxRq  
nSplitter = nCount; +v'2s@e` #  
} TvS<;0~K  
} 4[&&E7]EX  
N8k=c3|  
XR 3 dG:  
/* d[5v A/8O  
**Utility.java /9,'.  
*/ .'$8Hj;@  
package NetFox; '9zKaL  
dG8mE&$g  
c5uC?b].  
public class Utility { 6k![v@2R  
xB[W8gQ6fa  
5`$!s17  
public Utility() XA(.O|VZ  
{  (:o:_U  
b|@zjh;]A7  
"FhC"}N  
} *DXX*9 0  
GN Ewq$  
//线程睡眠 ~-y&C%  
public static void sleep(int nSecond) {0n p  
{ |(2#KMEWa  
try{ b:r8r}49  
Thread.sleep(nSecond); _cC1u7U9  
} 1 0.Z Bfn  
catch(Exception e) r NKeY48\  
{ _~{J."q  
e.printStackTrace (); P;-.\VRu  
} 2VUN  
} r%WHYhD  
Oo-4WqRJ  
//日志 m/jyc# L:u  
public static void log(String sMsg) %'=2Jy6h  
{ "KS" [i!3j  
System.err.println(sMsg); 7'65+c[&  
} gm n b  
evD=]iVD  
!syyOfu`}  
public static void log(int sMsg) fAz4>_4  
{ NFtA2EMLu[  
System.err.println(sMsg); |(TEG.<g  
} Y2'HP)tfIw  
} rBU)@IpDG  
.qKfhHJ  
o8H\l\(  
/* 98| v.d  
**TestMethod.java FGie*t  
*/ >R_m@$`  
package NetFox; \ykA7Y%  
{T,}]oX  
US^%pd  
public class TestMethod { $T:;Kc W)  
<P ?gP1_zi  
2xiE#l-V2  
public TestMethod() B2*>7 kc_s  
{ ///xx/weblogic60b2_win.exe n @R/zy  
try{ lZe-A/E  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); s-(c-E09  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9z{g3m70@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tS5J{j>T  
fileFetch.start(); #G?#ot2o  
} f*88k='\W  
catch(Exception e){e.printStackTrace ();} y29G#Y4J  
Q9h=1G\K  
5} <OB-9  
} E(_k#X  
Rq e|7/As  
ZZwIB3sNhf  
public static void main(String[] args) zBwqIJfM  
{ u|.|dv'mbp  
new TestMethod(); P*>?/I`G  
} lj8ficANo  
} $cuBd  
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