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http断点续传简单实现(java)

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/* L9^h .Y7  
**SiteFileFetch.java hWAZP=H  
*/ "!z9UiA  
package NetFox; IiB"F<&[j{  
import java.io.*; +^<-;/FZue  
import java.net.*; Av,E|C  
UlH;0P?  
vI0::ah/  
public class SiteFileFetch extends Thread { o 4cqLM u  
>Ni<itze$i  
&vV_,$  
SiteInfoBean siteInfoBean = null; //文件信息Bean "2>_eZ#b  
long[] nStartPos; //开始位置 MB!$s_~o#L  
long[] nEndPos; //结束位置 <,huajQs  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 zOT(>1'  
long nFileLength; //文件长度 ,_!MI+o0  
boolean bFirst = true; //是否第一次取文件 3-U@==:T  
boolean bStop = false; //停止标志 sHf.xc  
File tmpFile; //文件下载的临时信息 `%Jq^uW  
DataOutputStream output; //输出到文件的输出流 HK4 *+  
yGX"1Fb?;x  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) X.FFBKjf[e  
public SiteFileFetch(SiteInfoBean bean) throws IOException rF)[ Sed:T  
{ 1%k$9[!l%  
siteInfoBean = bean; Uv%?z0F<C  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3!2TE-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &pEr;:E  
if(tmpFile.exists ()) E;Q ,{{#  
{ b&xlT+GN  
bFirst = false; D9-D%R,  
read_nPos(); D/TEx2.=J3  
} G;yh$n<"  
else +5oK91o[y  
{ bqSp4TI  
nStartPos = new long[bean.getNSplitter()]; xZ(f_Oy  
nEndPos = new long[bean.getNSplitter()]; &C6Z{.3V  
} 6\GL|#G  
d!#qBn$*[  
Gb_y"rx?0  
m+'vrxTY  
} !)+8:8H'  
6rg?0\A<  
KQ2jeJ/pj  
public void run() '.1_anE]  
{ ~"8)9&  
//获得文件长度 A-5'OI  
//分割文件 * v W#XDx  
//实例FileSplitterFetch V7q-Pfh!y  
//启动FileSplitterFetch线程 Y/Q/4+  
//等待子线程返回 g!.k>  
try{ #b5V/)K  
if(bFirst) ~E*`+kD  
{ ,{VC(/d  
nFileLength = getFileSize(); ?h7(,39^>  
if(nFileLength == -1) `&!J6)OJ  
{ &0*IN nlc?  
System.err.println("File Length is not known!"); BZ"+ ND9m_  
} x/^,{RrPk  
else if(nFileLength == -2) 61=D&lb  
{ %\QK/`krp  
System.err.println("File is not access!"); Y=YIz>u  
} e QGhX(  
else t%Hy#z1W_  
{ 9~6)u=4sS"  
for(int i=0;i<nStartPos.length;i++) Kt\#|-{CH-  
{ 9e>Dqlv  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); LJ+Qe%|  
} mOE%:xq9-  
for(int i=0;i<nEndPos.length-1;i++) Ed+"F{!eQ  
{ ">hOD'PG  
nEndPos = nStartPos[i+1]; b%"Lwqdr7  
} TX7]$Wj  
nEndPos[nEndPos.length-1] = nFileLength; Cp[ NVmN  
} j& ~`wGM  
} 6|AD]/t^K  
M^3pJ=;5  
qt{{q  
//启动子线程 RJO40&Z<Z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; v cZg3:j  
for(int i=0;i<nStartPos.length;i++) :UDT! 5FNO  
{ B`i 5lD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q#!]5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), JOvRU DZ  
nStartPos,nEndPos,i); <C6*-j1oz  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AHl1{* [  
fileSplitterFetch.start(); [d}AlG!  
} 7GVI={ b  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z[pMlg6Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /Xo8 kC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", N6wCCXd  
nEndPos = " + nFileLength); ]> 36{k]&  
// fileSplitterFetch[nPos.length-1].start(); ic]b"ItD  
\C eP.,<  
>Qg 9KGk'  
//等待子线程结束 W]U}, g8Z  
//int count = 0; _)6N&u8  
//是否结束while循环 { i2QLS  
boolean breakWhile = false; By7? <A  
d9kN @W  
klwNeGF]N  
while(!bStop) 3sy|pa  
{ Sp>v`{F  
write_nPos(); /;rPzP4K6  
Utility.sleep(500); S B# Y^!  
breakWhile = true; Vim*4^[#L  
@#CZ7~Hn  
8BgHoQ*  
for(int i=0;i<nStartPos.length;i++) oR_qAb  
{ 1QPS=;|)  
if(!fileSplitterFetch.bDownOver) #y:,owo3I  
{ m_pqU(sP  
breakWhile = false; ~qP_1() ?  
break; SV}C]<  
} ZI>')T<@j"  
} ,2C{X+t  
if(breakWhile) gvLzE&V}  
break; ?5e]^H}  
,9@JBV%_  
K,' v{wSr  
//count++; OqcM3#  
//if(count>4) W-UMX',0zS  
// siteStop(); 0/@ ^He8l  
} IVblS iFF  
-4IHs=`;I  
/suW{8A(E  
System.err.println("文件下载结束!"); 2S^:fm}  
} rrL gBeQa  
catch(Exception e){e.printStackTrace ();} 8\H*Z2yF+  
} 9KgGK cy%  
Gi=s|vt  
Jv+N/+M47  
//获得文件长度 @V>BG8Y  
public long getFileSize() jFr[T  
{ d%wy@h  
int nFileLength = -1; 8uZM%7kI6+  
try{ fKYR DGn  
URL url = new URL(siteInfoBean.getSSiteURL()); 4,)EG1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O7of9F~"  
httpConnection.setRequestProperty("User-Agent","NetFox"); H/?@UJ5m  
RL|d-A+;  
X{YY)}^  
int responseCode=httpConnection.getResponseCode(); a?dUJt  
if(responseCode>=400) o6 l CP&  
{ fC7rs5  
processErrorCode(responseCode); $t{;- DpNB  
return -2; //-2 represent access is error 'Jl |-RUd  
} 7}r6mr0vpm  
"7X[@xX@  
{k"t`uo_  
String sHeader; 9>I&Z8J$M  
(O@fgBM  
<Mq vGXI  
for(int i=1;;i++) 7XU$O$C  
{ ](2\w9i%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L)qDtXd4  
//Utility.log(in.readLine()); $]`rWSYtv`  
sHeader=httpConnection.getHeaderFieldKey(i); R|u2ga ~  
if(sHeader!=null) c`E0sgp  
{ |@*3 nb8  
if(sHeader.equals("Content-Length")) Ua2waA  
{ wS"`~Ql_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Dm+[cA"I  
break; :H(wW   
} Q dPqcw4+X  
} H,q-*Kk  
else +~[>Usf  
break; 3Ud{W$Ym  
} !+(c/ gwBh  
} gx ]5)O  
catch(IOException e){e.printStackTrace ();} y`Nprwb  
catch(Exception e){e.printStackTrace ();} <<M1:1  
LyuA("xB#  
Zk:_Yiki&  
Utility.log(nFileLength); qvs&*lBY  
>f*-9  
RoLN#  
return nFileLength; 089 <B& <  
} ]p-x ds#d  
w}WfQj  
=v:}{~M^$  
//保存下载信息(文件指针位置) vXLGdv::  
private void write_nPos() Mc@_[q!xY?  
{ kuI$VC  
try{ JUpb*B_z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); pt_]&3\e  
output.writeInt(nStartPos.length); vKFEA7  
for(int i=0;i<nStartPos.length;i++) [fZhfZ)<  
{ lK%)a +2  
// output.writeLong(nPos); <To$Hb,NP  
output.writeLong(fileSplitterFetch.nStartPos); F6Ne?[b  
output.writeLong(fileSplitterFetch.nEndPos); %)#yMMhR  
} e,D RQ2AU  
output.close(); 5I>a|I!j  
} s^R$u"pFs  
catch(IOException e){e.printStackTrace ();} 3\2^LILLO  
catch(Exception e){e.printStackTrace ();} eZdFfmYW^R  
} 9cXL4  
UpSa7F:Uw  
qp{3I("_  
//读取保存的下载信息(文件指针位置) V M{Sng  
private void read_nPos() *ORa@ x  
{ L}UrI&]V$:  
try{ ,~G:>q$ad  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q>g-xe 1  
int nCount = input.readInt(); <0btwsv}  
nStartPos = new long[nCount]; H.]p\ UY9  
nEndPos = new long[nCount]; 044Q>Qz,  
for(int i=0;i<nStartPos.length;i++) JE_GWgwdv  
{ aHkt K/  
nStartPos = input.readLong(); -,qGEJ  
nEndPos = input.readLong(); AK//]   
} a^eR~efdu@  
input.close(); Txa 2`2t7  
} 1deK}5'  
catch(IOException e){e.printStackTrace ();} %zYTTPLZ  
catch(Exception e){e.printStackTrace ();} xFA+Zj BC  
} Pah*,  
/:ju/ ~R}  
qS/ 'Kyp_  
private void processErrorCode(int nErrorCode) 4Dw| I${O  
{ k[a5D/b  
System.err.println("Error Code : " + nErrorCode); sp7#e%R\  
} -#`tS  
ZfU &X{  
_Rk>yJD7s  
//停止文件下载 Ch'e'EmI  
public void siteStop() ]vjMfT%]W  
{ T?KM}<$(O  
bStop = true; },%, v2}  
for(int i=0;i<nStartPos.length;i++) S76x EL  
fileSplitterFetch.splitterStop(); $VJE&b  
4bq+(CI6  
\F9HsR6  
} [H=l# W@  
} <Q@{6  
//负责部分文件的抓取 ?8ady% .ls  
**FileSplitterFetch.java H8A=]Gq  
*/ h3(B7n7  
package NetFox; \=j|ju3  
:a*F>S!  
LM*m> n*  
import java.io.*; ')Qb,#/,%  
import java.net.*; 7,3 g{8  
L"'L@ A|U  
BYZllwxwTE  
public class FileSplitterFetch extends Thread { J:dNV <A^  
"u3 N9  
>K 7]G?+7E  
String sURL; //File URL , L5.KwB  
long nStartPos; //File Snippet Start Position (Eo#oX  
long nEndPos; //File Snippet End Position R_duPaWc@  
int nThreadID; //Thread's ID fO}Y$y\q  
boolean bDownOver = false; //Downing is over k8w:8*y'.  
boolean bStop = false; //Stop identical 4`p[t;q  
FileAccessI fileAccessI = null; //File Access interface vFK!LeF%  
]//D d/L6  
RJE<1!{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [(iJj3s!  
{ W:1GY#Pe  
this.sURL = sURL; kj@m5`G  
this.nStartPos = nStart; :o_6  
this.nEndPos = nEnd; zvKypx  
nThreadID = id; kYu"`_n}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !$!"$-5  
} E@8&#<  
G\Q0{4w8  
}b / G{92  
public void run() fH 0&Wc3yC  
{ R QCKH]&!  
while(nStartPos < nEndPos && !bStop) |$`I1  
{ @\Yu?_a  
V3[>^ZCA  
x<>In"QV  
try{ /S`d?AV  
URL url = new URL(sURL); e[%g'}D:-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ktiC*|fd  
httpConnection.setRequestProperty("User-Agent","NetFox"); |c:xK{Ik  
String sProperty = "bytes="+nStartPos+"-"; ~c|{PZ9U  
httpConnection.setRequestProperty("RANGE",sProperty); N=;VS-  
Utility.log(sProperty); N  Bpf  
6@J)k V  
$jN,] N~  
InputStream input = httpConnection.getInputStream(); /;9]LC.g  
//logResponseHead(httpConnection); 0[!38  
''wF%q  
QO3QR/Ww  
byte[] b = new byte[1024]; +\~Mx>Cn  
int nRead; *!u a?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) K2ry@haN  
{ ZJ}|t  
nStartPos += fileAccessI.write(b,0,nRead); "uD^1'IW2  
//if(nThreadID == 1) z/t+t_y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z$ 6yB  
} /Avl&Rd  
E{E%nXR)  
:\,3=suWq  
Utility.log("Thread " + nThreadID + " is over!"); =xPBolxm5U  
bDownOver = true; Y 9~z7  
//nPos = fileAccessI.write (b,0,nRead); usOIbrQ  
} &&($LnyA]  
catch(Exception e){e.printStackTrace ();} `KJ BQK  
} v1~`76^  
} v`9n'+h-c6  
<rFKJ^B  
r?wE;gH  
//打印回应的头信息 -,} ppTG  
public void logResponseHead(HttpURLConnection con) M\jTeB"Z  
{ 2Ls  
for(int i=1;;i++) \7A6+[ `fa  
{ m'ykDK\B  
String header=con.getHeaderFieldKey(i); *m`KY)b=l  
if(header!=null) Auf2JH~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); jl~?I*Gr  
Utility.log(header+" : "+con.getHeaderField(header)); &ajpD sz;  
else ($Y6hn+  
break; a%)-iL X8&  
} |T^c(RpOE  
} R{A$hnhW6  
MYF6tZ*  
nh+f,HtSt  
public void splitterStop() . [5{  
{ f iu?mb=*  
bStop = true; jwZBWt )5  
} w65D;9/;  
G9P)Y#WB  
nK5FPFz8  
} &[ 4lP~  
K(B|o6[  
gv,8Wo  
/* :,BKB*a\  
**FileAccess.java }dO^q-t$3  
*//文件访问(定位,写) 9?#L/  
package NetFox; K\`>'C2_V  
import java.io.*; s6J`i&uu  
1b-_![&]1  
tN:PWj5  
public class FileAccessI implements Serializable{ nnPY8pdjSD  
%{ToWLb{I  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C"!k`i=Lj  
RandomAccessFile oSavedFile; ds"q1  
long nPos; sZ9VXnz24  
)I`Ma6bX  
Zqnwf  
public FileAccessI() throws IOException x-HN]quhe  
{ x)Ls(Xh+g  
this("",0); vZl]C%  
} qg#|1J6e  
~kW[d1'c  
+>wBGVvS  
public FileAccessI(String sName,long nPos) throws IOException FOx&'dH %@  
{ O$,MdhyXC  
oSavedFile = new RandomAccessFile(sName,"rw"); >|@i8?|E  
this.nPos = nPos; ~i y]X:U  
oSavedFile.seek(nPos); ?#0|A?U  
} 0O:')R&  
[:(^n0%  
_M;M-hk/  
public synchronized int write(byte[] b,int nStart,int nLen) Uc?#E $X  
{ oWo/QNw9  
int n = -1; WVfwt.Y  
try{ H~Fb=.h]U  
oSavedFile.write(b,nStart,nLen); kKP<K+hH  
n = nLen; 5x:dhkW  
} @fSBW+  
catch(IOException e) =1'vXPv`  
{ ]1(G:h\  
e.printStackTrace (); -*T<^G;rK  
} d`+@ _)ea  
n^2p jTkl  
M$0-!$RY  
return n; _#]/d3*Z}  
} lEe<!B$d"  
A\v(!yg  
@ =M:RA  
} ,_(AiQK  
8A ;)5!  
_`(WX;sK  
/* n$O[yRMI[  
**SiteInfoBean.java hPB^|#}  
*/ <//#0r*  
package NetFox; d1rIU6  
7A mnxFC  
F$k^px  
public class SiteInfoBean { ?'$Yj>R6  
?' :v): J}  
awic9 uMH  
private String sSiteURL; //Site's URL BQ7p<{G  
private String sFilePath; //Saved File's Path H ]x-s  
private String sFileName; //Saved File's Name /$ :w8  
private int nSplitter; //Count of Splited Downloading File )Z0bMO<  
yxx'g+D*  
GF=rGn@,)`  
public SiteInfoBean() B3V;  
{//nSplitter的缺省值为5 HDY2<Hzc  
//default value of nSplitter is 5 e 1$<,.>  
this("","","",5); aF41?.s  
} ,p\:Z3{ZH  
Adma~]T9  
^L@2%}6b`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e: aa  
{ d~F4  
sSiteURL= sURL; .*(xkJI3  
sFilePath = sPath; 4Lb!Au|Y  
sFileName = sName; ~0 Ifg_G  
this.nSplitter = nSpiltter; hE|W%~Jx  
&Q`{ Gk  
C3"5XR_Ov  
} j @HOU~x  
'fIoN%  
0lm7'H*~  
public String getSSiteURL() H-|%\9&{S  
{ Ap<kK0#h  
return sSiteURL; ZZu{c t9  
} :+q d>;yf#  
7H l>UX,|  
 h/*q +H  
public void setSSiteURL(String value) ,|RN?1?U  
{ L]kd.JJvy  
sSiteURL = value; !w;oVPNg  
} =+z+`ot  
HPz3"3n!  
:yi?<  
public String getSFilePath() {gkzo3  
{ EQTJ=\WFF  
return sFilePath; 6^l|/\Y{  
} w5+H9R6  
+ ;LO|!  
lPyY  
public void setSFilePath(String value) J_S8=`f%  
{ r&y0`M  
sFilePath = value; 31^Jg  
} qC x|}5:  
Kt#_Ln_6  
uSgR|b;R]  
public String getSFileName() YstR T1  
{ (xdC'@&  
return sFileName; e1OGGF%E n  
} $Vp*,oRL  
.US=fWyrb  
~~\C.6c#  
public void setSFileName(String value) H-&T)  
{ v6 C$Y+5~  
sFileName = value; e=^^TX`I  
} 2Wn*J[5  
K'_qi8Z  
\]8 F_K  
public int getNSplitter() uo8[,'  
{ VtN1 [}  
return nSplitter; \'Q rJ ?D  
} CBr(a'3{Z  
3%[;nhbA7  
g2;lEW  
public void setNSplitter(int nCount) ;p+[R+ )  
{ [eO^C  
nSplitter = nCount; :;hz!6!  
} 7,lnfCm H  
} lsaA    
abD@0zr  
lDSF  
/* xwF mY'o  
**Utility.java 3Cw}y55_y  
*/ %vil ~NU  
package NetFox; YSh@+AN  
0,/I2!dF?  
jQrj3*V  
public class Utility { vc0LV'lmg  
er8T:.Py  
; I;&O5Y  
public Utility() SF=TG84<  
{ $niG)@*  
Kr5(fU  
AP:Q]A6}  
} I`f5)iF?0  
\$4 [qG=  
//线程睡眠 ]t0St~qUL)  
public static void sleep(int nSecond) J%u,qF}h  
{ 'Qh1$X)R7a  
try{ T-LX>*  
Thread.sleep(nSecond); kV+%(Gl8  
} c'.XC}  
catch(Exception e) lvsj4 cT  
{ !-t,r%CG  
e.printStackTrace (); "Ccyj/  
} 16ZyLt  
} `Gj(>z*  
dEZUK vo  
//日志 lrAhdi  
public static void log(String sMsg) -VeC X]  
{ xg}Q~,:  
System.err.println(sMsg); 0NeIQr1N_  
} *`q?`#1&&.  
", p5}}/  
%tMx48'N  
public static void log(int sMsg) lSg[7lt  
{ !:PiQ19 'u  
System.err.println(sMsg); -.Blj<2ah  
} _%[po%]  
} YF)]B|I  
mqj-/DN6*  
~Pj q3etk  
/* (3"N~\9m  
**TestMethod.java %.m+6 zaF  
*/ ZTibF'\5N  
package NetFox; -&COI-P8  
XEnu0 gr  
W=#AfPi$&  
public class TestMethod { }v's>Ae~p  
OXm`n/64+  
T](}jQxj`  
public TestMethod() R G*Vdom  
{ ///xx/weblogic60b2_win.exe $AT@r"  
try{ 9QaE)wt  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?ac4GA(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z\$M)e8n  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -V4%f{9T3  
fileFetch.start(); QgI[#d{  
} y^"@$   
catch(Exception e){e.printStackTrace ();} p- a{6<h  
i y8Jl  
0,nz*UDk  
} - V:HT j  
,3!$mQL=  
*E*oWb]H  
public static void main(String[] args) {zWR)o .=  
{ 9b/Dswxjx  
new TestMethod(); ESNI$[`  
} @ 5^nrB  
} -OSj<m<  
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