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http断点续传简单实现(java)

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/* 2sWM(SN  
**SiteFileFetch.java o^5xCK:Oi2  
*/ iQs(Dh=*  
package NetFox; dt ;R  
import java.io.*; H?^Poe(=(  
import java.net.*; ,9  
}J"}poB:  
P62g7>B5^  
public class SiteFileFetch extends Thread { ]6FpUF#<D  
bIwt#:v  
P(qUx9  
SiteInfoBean siteInfoBean = null; //文件信息Bean LXfDXXF  
long[] nStartPos; //开始位置 u9sffX5x[J  
long[] nEndPos; //结束位置  xUzfBn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 m$0T"`AP`  
long nFileLength; //文件长度 mWCY%o@  
boolean bFirst = true; //是否第一次取文件 Q+Jzab  
boolean bStop = false; //停止标志 8 w^i  
File tmpFile; //文件下载的临时信息 \*a7DuVw  
DataOutputStream output; //输出到文件的输出流 @k ~Xem%<  
aElEV e3  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) T [&1cth  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6YYZ S2  
{ =d&  
siteInfoBean = bean; -=2tKH`Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0zdH6 &  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ocGqX Dg3  
if(tmpFile.exists ()) m03;'Nj'7#  
{ M~p=OM<  
bFirst = false; +-K-CXt  
read_nPos(); 8^^Xr  
} 4GeWo@8h  
else ;1K.SDj  
{ x4R[Q&:M  
nStartPos = new long[bean.getNSplitter()]; U $e-e/  
nEndPos = new long[bean.getNSplitter()]; )Q&:$]  
} 0P&rTtU6  
Z[Uz~W6M]  
0ir]  
mp>,TOi~s7  
} qAHQZKk  
3|l+&LF!IC  
T" XZ[q  
public void run() $x#Y\dpS  
{ `a98+x?JF  
//获得文件长度 Ryr2  
//分割文件 /vBOf;L  
//实例FileSplitterFetch 68W&qzw.[r  
//启动FileSplitterFetch线程 FE" ksi 9  
//等待子线程返回 F@)wi0  
try{ ~UEft  
if(bFirst) ^4h/6^b0c  
{ <jY"+@rF  
nFileLength = getFileSize(); bK<'J=#1  
if(nFileLength == -1) Mb"i}Yt{  
{ J *5 )g  
System.err.println("File Length is not known!"); `o)rAD^e  
} %F]4)XeW-+  
else if(nFileLength == -2) K;k&w; j  
{ josc  
System.err.println("File is not access!"); MXq+aS{  
} m\O<Yc keA  
else 6;"jq92in*  
{ R>BnUIu  
for(int i=0;i<nStartPos.length;i++) -5\hZ!!J2  
{ u @?n3l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); oZQ% P  
} LlrUJ-uC7  
for(int i=0;i<nEndPos.length-1;i++) Xg_M{t  
{ f{t5r  
nEndPos = nStartPos[i+1]; z~# .Ey  
} _ 2R;@[f2  
nEndPos[nEndPos.length-1] = nFileLength; 4'RyD<K\  
} GNgPf"}K  
} &k+ jVymH  
BRi\&&<4  
0P3^#j  
//启动子线程 6X$]d^)h{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Oc}4`?oy<O  
for(int i=0;i<nStartPos.length;i++) h2QoBGL5  
{ [:&4Tp*C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WA \ P`'lg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5RrzRAxq  
nStartPos,nEndPos,i); { r yv7G  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %scSp&X  
fileSplitterFetch.start(); }4Ef31X8q  
} xKi: 2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q@1b{q#C5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); rF'_YYpr>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", AvfSR p  
nEndPos = " + nFileLength); K -cRNt  
// fileSplitterFetch[nPos.length-1].start(); Y`eUWCD  
(J I4ibP  
h8iic  
//等待子线程结束 \fj* .[,  
//int count = 0; ANR?An  
//是否结束while循环 _a|-_p  
boolean breakWhile = false; airg[dK  
p6VS<L  
]|KOc& y:I  
while(!bStop) zy^t95/m  
{ ue"?n2  
write_nPos(); V+G.TI P  
Utility.sleep(500); nd_+g2x'  
breakWhile = true; (S3\O `5  
HRS^91aK  
He @d~9M  
for(int i=0;i<nStartPos.length;i++) #&u9z5ywM  
{ :08b&myx  
if(!fileSplitterFetch.bDownOver) l|TiUjs  
{ 6jyS]($q  
breakWhile = false; [CTE"@A  
break; 2#%@j6  
} %#kml{I   
} t@m!k+0  
if(breakWhile) < Ih)h$8`  
break; r {R879  
)(V|d$n  
.dM4B'OA?  
//count++; rWsUWA T*  
//if(count>4) %xv }  
// siteStop(); j N":9+F  
} V9  Z  
90<z*j$EK  
2%o@?Rp  
System.err.println("文件下载结束!"); b/"&E'5-`\  
} "V|&s/9  
catch(Exception e){e.printStackTrace ();} StZ GKY[Q  
} mu`:@7+Yp  
P`^3-X/  
T)4pLN E  
//获得文件长度 CNP!v\D  
public long getFileSize() [[ {L#  
{ t,H=;U#  
int nFileLength = -1; O\0]o!  
try{ &q8oalh  
URL url = new URL(siteInfoBean.getSSiteURL()); mcO/V-\5'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d rRi<7 i  
httpConnection.setRequestProperty("User-Agent","NetFox"); W@S>#3,  
pe%$(%@v  
W5a7HkM  
int responseCode=httpConnection.getResponseCode(); '$nm~z,V  
if(responseCode>=400) &}}UdJ`  
{ fib#)KE  
processErrorCode(responseCode); % \N52  
return -2; //-2 represent access is error 8);G'7O  
} iwM$U( 9  
J[0o 6  
r2!\Ts5v  
String sHeader; H 5\k`7R  
5=cS5q@  
L F<{/c9,  
for(int i=1;;i++) vT1StOx<V  
{ iG+hj:5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); k9Pwf"m|](  
//Utility.log(in.readLine()); gs/ i%O  
sHeader=httpConnection.getHeaderFieldKey(i); Vd%%lv{v  
if(sHeader!=null) ~F; ~  
{ dbVMG-z8  
if(sHeader.equals("Content-Length")) R"Ff(1m  
{ T- ~l2u|s  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Pk{eGG<F$  
break; E]@$,)nC  
} )O}q{4,}  
} ,76xa%k(U|  
else L'A9TW2  
break; -2DvKW$  
} +wPXDN#R  
} cpLlkR O  
catch(IOException e){e.printStackTrace ();} JJE?!Yvc  
catch(Exception e){e.printStackTrace ();} <A~a|A-QFR  
Dt]N&E#\D  
A  [c1E[  
Utility.log(nFileLength); `PoFKtVX M  
-6KNMk   
r%=}e++^%  
return nFileLength; Po B-:G6  
} ,y>Sq +  
Z.QgL=  
r3;@  
//保存下载信息(文件指针位置) :o"9x,  
private void write_nPos() mZG)#gW[  
{ G>@KX  
try{ ;URvZ! {/Z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); THN/ /}d  
output.writeInt(nStartPos.length); WWBm*?U  
for(int i=0;i<nStartPos.length;i++) NP#6'eH\  
{ Q%T[&A}3B  
// output.writeLong(nPos); 1U?,}w   
output.writeLong(fileSplitterFetch.nStartPos); k.5(d.*(  
output.writeLong(fileSplitterFetch.nEndPos); I,8f{T!O@"  
} Ez)hArxns  
output.close(); Bz+zEXBC  
} R"2wop  
catch(IOException e){e.printStackTrace ();} U\'HB.P\  
catch(Exception e){e.printStackTrace ();} fV(WUN+  
} _/c1b>kcso  
ko-,l6E  
*r90IS}A$2  
//读取保存的下载信息(文件指针位置) -ZVCb@%  
private void read_nPos() tg~@(IT}j  
{ nhdOo   
try{ /}kG$ ~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |d)*,O4s  
int nCount = input.readInt(); $S6%a9m   
nStartPos = new long[nCount]; d YliC  
nEndPos = new long[nCount]; u5Tu~  
for(int i=0;i<nStartPos.length;i++) T9'd?nw9  
{ jL6ZHEi#d7  
nStartPos = input.readLong(); 7{ JIHY+  
nEndPos = input.readLong(); >}7Ml  
} 'qy LQ:6  
input.close(); t@vVE{`  
} Kg;u.4.-M  
catch(IOException e){e.printStackTrace ();} I%<LLkQ  
catch(Exception e){e.printStackTrace ();} l^k/Y ]  
} iwVsq_[]L  
yQz6K6p  
;Pw\p^wz  
private void processErrorCode(int nErrorCode) $p;<1+!  
{ 6"djX47j  
System.err.println("Error Code : " + nErrorCode); AY x*Ngn  
} P]^ BE;7T  
}nx5  
(~IoRhp^  
//停止文件下载 ,L&d\M"f  
public void siteStop() [C^&iLX/F*  
{ pf8M0,AY  
bStop = true; asc Y E  
for(int i=0;i<nStartPos.length;i++) ^&Vj m  
fileSplitterFetch.splitterStop(); Q8Fqf ;4  
xg;I::hE7X  
wrhGZ=k{  
} J\l'nqS"  
} 259R5X<V  
//负责部分文件的抓取 %y|L'C,ge"  
**FileSplitterFetch.java 4Q17vCC*n  
*/ =kP|TR!o-  
package NetFox; Liv.i;-qE  
`UD,ne  
w!|jL $5L  
import java.io.*; or qL0i  
import java.net.*; uA[c$tBe  
H3 >49;`  
zL!}YR@&u"  
public class FileSplitterFetch extends Thread { S&J>15oWM`  
evvv&$&  
s+<`iH9Hm  
String sURL; //File URL xOt {Vsv  
long nStartPos; //File Snippet Start Position [[7=rn}@<  
long nEndPos; //File Snippet End Position 3C gmZ7[  
int nThreadID; //Thread's ID ty\F~]Oo  
boolean bDownOver = false; //Downing is over OPuty/^!Gw  
boolean bStop = false; //Stop identical S;K5JBX0#  
FileAccessI fileAccessI = null; //File Access interface <~teD[1k"  
_Kwp8_kTr  
5ktFL<^5T  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]|_UpP8EP  
{ =/e$Rp  
this.sURL = sURL; +~n4</  
this.nStartPos = nStart; :|a$[g5  
this.nEndPos = nEnd; cH:9@>'$a  
nThreadID = id; Ay@/{RZz  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 83!{?EPE  
} T f40lv+{  
6an= C_Mb`  
6]|-%  
public void run() z'&tmje[?  
{ z 4qEC  
while(nStartPos < nEndPos && !bStop) _;mA(j  
{ F*-+5nJ&@  
Q2Dh(  
_$KE E|9  
try{ nrV!<nNBk  
URL url = new URL(sURL); "F:V$,mJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Vji:,k=3\  
httpConnection.setRequestProperty("User-Agent","NetFox"); |)*9BN  
String sProperty = "bytes="+nStartPos+"-"; {,B. OM)J  
httpConnection.setRequestProperty("RANGE",sProperty); B:96E&  
Utility.log(sProperty); 7{lWg x  
: "^/?Sd  
kx,3[qe'S  
InputStream input = httpConnection.getInputStream(); %v4*$E!f  
//logResponseHead(httpConnection); 5t,X;  
i`}!<{k  
zJ30ZY:  
byte[] b = new byte[1024]; \Mzr[dI  
int nRead; ?kULR0uL+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W3gHz T?{  
{ O>"T*   
nStartPos += fileAccessI.write(b,0,nRead); YYhN>d$  
//if(nThreadID == 1) _>J`e7j+  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F~sUfqiJ'  
} t|m=X  
WD@v<Wx)  
=Eb$rc)  
Utility.log("Thread " + nThreadID + " is over!"); ws<p BC,m  
bDownOver = true; .*B@1q  
//nPos = fileAccessI.write (b,0,nRead); E[Q2ZqhgbP  
} wGw<z[:f  
catch(Exception e){e.printStackTrace ();} b}&.IJ&40j  
} /@64xrvIl=  
} VwKfM MI8  
MZ?+I~@  
TVF:z_M9  
//打印回应的头信息 Vn65:" O  
public void logResponseHead(HttpURLConnection con) @<3kj R?j  
{ twhT6wz"  
for(int i=1;;i++) ; +1ooeU  
{ wf_ $#.;m  
String header=con.getHeaderFieldKey(i); >Cam6LJ  
if(header!=null) 5<M$ XT  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #&b<D2d  
Utility.log(header+" : "+con.getHeaderField(header)); 3^iVDbAW{  
else XAN.Plk  
break; {:#c1d2@8  
} N;a'`l  
} WfHa  
n lZJ}xZ  
1)3'Y2N*  
public void splitterStop() Wuk!\<T{  
{ $Wu|4]o>9  
bStop = true; L2c\i  
} g 'td(i[  
D&x.io  
L|nFN}da  
} y@SI)&D  
klMpiy  
KGGnypx`  
/* 6tGF  
**FileAccess.java yg6o#;  
*//文件访问(定位,写) wq|7sk{  
package NetFox; &dPI<HlM  
import java.io.*; N8DouDq  
Y$#6%`*#>n  
ktkS$  
public class FileAccessI implements Serializable{ 3:)_oHq  
%)Z,?DzZ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Res4;C  
RandomAccessFile oSavedFile; Tz~a. h@  
long nPos; 6E2#VT>@/  
|h\A5_0_  
T oT('  
public FileAccessI() throws IOException jZH4]^De  
{ uqD|j:~ =k  
this("",0); s@E) =;!  
} nvA7eTO6C  
L F&!od9[  
E:-~SH}  
public FileAccessI(String sName,long nPos) throws IOException S|T_<FCY  
{ f&txg,W,yv  
oSavedFile = new RandomAccessFile(sName,"rw"); 96S$Y~G# &  
this.nPos = nPos; !K+hXQE1  
oSavedFile.seek(nPos); 1h#/8 X  
} u08j9) ,4  
RY3=UeoF  
+~|Jn_:A f  
public synchronized int write(byte[] b,int nStart,int nLen) G.$KP  
{ fQ1Dp  
int n = -1; I Bko"|e@  
try{ #M<YNuE#"  
oSavedFile.write(b,nStart,nLen); F'"-aB ~  
n = nLen; S;u.Ds&  
} 4 9HP2E  
catch(IOException e) qL <@PC.5  
{  vY"I  
e.printStackTrace (); o2;Eti  
} i'10qWz  
0~P]Fw^w  
;mg.} fI  
return n; .V\~#Ro$G  
} hi4-Z=pl  
&M tF  
[mj=m?j  
} cB_9@0r[S  
J@QOF+&  
DliDBArxZ  
/* aHb&+/HZ  
**SiteInfoBean.java IwOL1\'T4  
*/ (N/-blto  
package NetFox; x iz+ R9p  
p&#ju*i6z  
-8vGvI>  
public class SiteInfoBean { Y; iI =U  
] _W'-B  
s Ytn'&$\  
private String sSiteURL; //Site's URL 4>2\{0r  
private String sFilePath; //Saved File's Path O9m sPb:  
private String sFileName; //Saved File's Name zo("v*d*q  
private int nSplitter; //Count of Splited Downloading File I[b{*g2Zw  
F/,6Jh  
"kC6G%  
public SiteInfoBean() wp'[AR}  
{//nSplitter的缺省值为5 lHPnAaue@  
//default value of nSplitter is 5 yE.st9m  
this("","","",5); nf[KD,f  
} =T#hd7O`V  
K4H27SH  
,1cpV|mAr  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) s];0-65)  
{ _00}O+GLM4  
sSiteURL= sURL; [mNum3e  
sFilePath = sPath; !vVW8hbp  
sFileName = sName; IWm@pfC+g  
this.nSplitter = nSpiltter; h~qv_)F_  
[w-Tf&  
\}%_FnP0ZU  
} I2pE}6q  
LE~vSm^#  
J`C 2}$ ~  
public String getSSiteURL() 4F6I7lu  
{ ~C3J-z<  
return sSiteURL; tOte[~,  
} |eg8F$WU  
xi4b;U j  
W$Xr:RU  
public void setSSiteURL(String value) PW iuM=E  
{ .:4*HB  
sSiteURL = value; I+ 3qu=  
} 6xY6EC  
}eI9me@Aa  
@P>>:002/  
public String getSFilePath() 8G2QI4  
{ B5h)F> &G  
return sFilePath; `sy_'`i>X  
} 8zcS h/  
f`K#=_Kq7  
`:R9M+ OX  
public void setSFilePath(String value) ,_/\pX0  
{ O2yD{i#l*#  
sFilePath = value; IP-M)_I  
} NPFI^Uj#A  
NH:Bdl3  
9i lJ  
public String getSFileName() 8e ?9:VM]  
{ +2k{y l  
return sFileName; \zBZ$5 rE  
} !KT.p2\  
#;lEx'lKN  
T+t7/PwC;  
public void setSFileName(String value) W5e >Z&&  
{ qsN_EMgbdn  
sFileName = value; .W$9nbly  
} :Ig9n :  
YHke^Ind  
(CtRU   
public int getNSplitter() *b!.9pK  
{ 6 {F#_.  
return nSplitter; F&^&"(H}  
} 1{RA\CF  
%KN2iNq  
%Wm)  
public void setNSplitter(int nCount) ( Rp5g}b  
{ j9w{=( MV  
nSplitter = nCount; +W$uHQq  
} -UAMHd}4  
} <Wj /A/  
~BgYD)ov  
Uq x@9z(  
/* oK<H/76x  
**Utility.java tNOOaj9mw  
*/ [#SO}'1n  
package NetFox; [9}<N2,9z  
,J<+Wxz  
w@YPG{"j  
public class Utility { Q,tjODc6n  
/QCg E ~  
aI}htb{m`  
public Utility() 4x=sJ%E  
{ ^ 5>W`vwp  
uINEq{yo  
8/y8tMm]  
} J-azBi  
mi5bk>o  
//线程睡眠 u*oP:!s  
public static void sleep(int nSecond) EG_P^ <z  
{ KV'3\`v@LY  
try{ .m%5Esx  
Thread.sleep(nSecond); hYA1N&yz@  
} c=a;<,Rzb  
catch(Exception e) : Q2=t!  
{ %kH,Rl\g  
e.printStackTrace (); X'%BS  
} h Y *^rY'  
} Nr"GxezU+A  
0C"2?etMx  
//日志 7|[Dr@.S  
public static void log(String sMsg) . S;o#Zw*R  
{ t:,lz8Y~  
System.err.println(sMsg); C.H(aX)7  
} *+2BZ ZwT  
W'E3_dj+  
BvHI}=  
public static void log(int sMsg) -- IewW  
{ CPY|rV  
System.err.println(sMsg); W>,D$  
} 2$2@?]|?  
} 31%3&B:Ts  
l Dwq[ I]w  
9\E];~"iP  
/* *$JS}Pax  
**TestMethod.java Q&PEO%/D  
*/  ;Yg/y  
package NetFox; m1tc="j  
hu}uc&N)iE  
&t'P>6)  
public class TestMethod { @00&J~D  
j.V7`x  
5l(@p7_+  
public TestMethod() 7E?60^Tve  
{ ///xx/weblogic60b2_win.exe goD#2lg  
try{ o?3C-A|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); cA]PZ*]{BN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5twG2p8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); dWo$5Bls<A  
fileFetch.start(); f,3K;S-he:  
} 83'rQDo)G  
catch(Exception e){e.printStackTrace ();} >=1UhHFNI  
Q(Pc  
k>E/)9%ep2  
} P8ns @VV  
n2["Ln mO  
Np.<&`p!  
public static void main(String[] args) THy   
{ YPw=iF]  
new TestMethod(); nA=E|$1  
} v|jwz.jM  
} 9om}j  
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