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http断点续传简单实现(java)

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/* ;X?mmv'  
**SiteFileFetch.java i\dc>C ;  
*/ C*`mM'#  
package NetFox; p ZZc:\fJ  
import java.io.*; _r2J7&  
import java.net.*; ai{Sa U  
a<@N-Exr  
G#?Sfn O0  
public class SiteFileFetch extends Thread { / 4lvP  
*W kIq>  
f"St&q>[s  
SiteInfoBean siteInfoBean = null; //文件信息Bean O)"gS!,  
long[] nStartPos; //开始位置 9D4NX<_  
long[] nEndPos; //结束位置 J&T.(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 '{(UW.Awo  
long nFileLength; //文件长度 0pbtH8~  
boolean bFirst = true; //是否第一次取文件 ;6!Pwb;hY  
boolean bStop = false; //停止标志 c_V;DcZ  
File tmpFile; //文件下载的临时信息 :hM/f  
DataOutputStream output; //输出到文件的输出流 G>q(iF'  
Ud!4"<C_  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) IV)<5'v  
public SiteFileFetch(SiteInfoBean bean) throws IOException v;0|U:`]  
{ 5Lf{8UxI  
siteInfoBean = bean; TYQwy*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); qkC/\![@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); VH[hsj  
if(tmpFile.exists ()) /"B?1?qc,=  
{ 6qaulwV4t  
bFirst = false; ndeebXw*  
read_nPos(); W>O~-2  
} 39=1f6I1  
else :duo#w"K  
{ =dFv/F/RW  
nStartPos = new long[bean.getNSplitter()]; W]nSR RWco  
nEndPos = new long[bean.getNSplitter()]; |<GDUwC_;  
} VP6ZiQ|  
yUp,NfS]o  
nH<eR)0  
'z[Sp~I\  
} SGe^ogO"v  
3Oi nK['  
VhNz8)  
public void run() Iyyh!MVF  
{ EbdfV-E  
//获得文件长度 TsGE cxIg  
//分割文件 }6@pJ G  
//实例FileSplitterFetch $k2*[sn,  
//启动FileSplitterFetch线程 tuhA 9}E  
//等待子线程返回 M`l.t -ut  
try{ *q1%IJ  
if(bFirst) ;dzL}@we  
{ -k"^o!p  
nFileLength = getFileSize(); }|XtypbL  
if(nFileLength == -1) Q^#;WASi  
{ B|&"#Q  
System.err.println("File Length is not known!"); EcCFbqS4W  
} IqD_GL)Ms  
else if(nFileLength == -2) M-giR:,  
{ AqV7\gdOC  
System.err.println("File is not access!"); pi ,eIm  
} o5Q{/  
else IzpZwx^3''  
{ 8A+SjJ4$  
for(int i=0;i<nStartPos.length;i++) GO^_=EMR[  
{ G rk@dZI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :at$HCaK  
} zNIsf "  
for(int i=0;i<nEndPos.length-1;i++) 1SR+m>pL  
{ r}jGUe}d  
nEndPos = nStartPos[i+1]; k0Uyf~p~  
} !H}vu]R  
nEndPos[nEndPos.length-1] = nFileLength; iV eC=^1  
} .3MIcj=p  
} /\W Qx e  
<0PT"ij  
,.qMEMm  
//启动子线程 r9ww.PpNk#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f?'JAC*  
for(int i=0;i<nStartPos.length;i++) wV ^V]c?U  
{ m2v'WY5u  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |\g5+fv9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), a! u rew#  
nStartPos,nEndPos,i); j<)9dEM'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); INyk3`FT  
fileSplitterFetch.start(); g'|MA~4yB  
} 3dRr/Ilc  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :bC40@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); eR3$i)5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R]i7 $}n  
nEndPos = " + nFileLength); x4/M}%h!;B  
// fileSplitterFetch[nPos.length-1].start(); 4X *>H  
HVC >9_:]  
PK4iuU`vh  
//等待子线程结束 ]TyisaT  
//int count = 0; &JtV'@>v  
//是否结束while循环 ^tCd L@$AS  
boolean breakWhile = false; ]C:l,I  
<&:=z?30"  
h`H,a7  
while(!bStop) +fnK /%b  
{ V.{H9n]IO  
write_nPos(); ;jipe3LU  
Utility.sleep(500); J:kmqk!  
breakWhile = true; \l@,B +)  
w-0mzk"  
q=9`06  
for(int i=0;i<nStartPos.length;i++) {pHM},WJ  
{ dS5a  
if(!fileSplitterFetch.bDownOver) l}lIi8  
{ RJ$7XCY%`*  
breakWhile = false; Y}vr>\  
break; gB4U*D0[e~  
} +a*^{l}AST  
} (S v~2  
if(breakWhile) $&2UTczp  
break; j8sH#b7Z  
/-i !;!  
6HlePTf8  
//count++; ,yTjU{<"  
//if(count>4) <fs2fTUeqF  
// siteStop(); s\P2Bp_{  
} 2^^=iU=!<|  
d`/tE?Gw  
G7CG~:3h+  
System.err.println("文件下载结束!"); zH*KYB  
} %zO h  
catch(Exception e){e.printStackTrace ();} d%0~c'D8a  
} MX ;J5(Ae  
FEJ~k1z  
EMc;^ d  
//获得文件长度 DK oN}c  
public long getFileSize() "kA*Vc#  
{ m-jHze`D3  
int nFileLength = -1; E~AjK'Z  
try{ D91e\|]  
URL url = new URL(siteInfoBean.getSSiteURL()); 3q?\r` a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T]?n)L,2  
httpConnection.setRequestProperty("User-Agent","NetFox"); "hy.GWF|*  
0pSmj2/,.  
@GvztVYo  
int responseCode=httpConnection.getResponseCode(); Z*FrB58  
if(responseCode>=400) K_ ci_g":  
{ C*G=cs\i  
processErrorCode(responseCode); U. @*`Fg  
return -2; //-2 represent access is error i>joT><B  
} @e'5E^  
RAp=s  
/P 2[:[w  
String sHeader; )<xypDQ  
&< !Ufa&  
2r 6'O6v  
for(int i=1;;i++) A'%1ZQ33O  
{ hbc uK&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "C*B,D*}:  
//Utility.log(in.readLine()); w` DW(hXJ  
sHeader=httpConnection.getHeaderFieldKey(i); bUY>st'  
if(sHeader!=null) `w.AQ?p@  
{ {Ixg2=E\  
if(sHeader.equals("Content-Length")) X7g3  
{ 8Mbeg ,P  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); I=!rbF;Z  
break; mB0l "# F  
} 1U,1)<z~u  
} QL$S4 J"  
else %xQ.7~  
break; .WQ+AE8Q  
} oQL59XOT4  
} 8+Td-\IMk  
catch(IOException e){e.printStackTrace ();} 2z@\R@F  
catch(Exception e){e.printStackTrace ();} 4);)@&0Md~  
B7Tk4q\;Q  
. ]8E7  
Utility.log(nFileLength); n\ Hs@.  
>~\89E 02  
MJ\eh>v&  
return nFileLength; %r iK+  
} k'PQ} ,Vb  
3.)b4T  
o#[ KS:Y  
//保存下载信息(文件指针位置) Q_vW3xz  
private void write_nPos() w%zRHf8C  
{ :>81BuMvg  
try{ nL?oTze*p  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H-p;6C<  
output.writeInt(nStartPos.length); K)_WL]RJ.4  
for(int i=0;i<nStartPos.length;i++) 9V.u-^o&  
{ \`w4|T  
// output.writeLong(nPos); u(!&:A9JFd  
output.writeLong(fileSplitterFetch.nStartPos); oW;6h.  
output.writeLong(fileSplitterFetch.nEndPos); ]LZ`LL'#Y_  
} k;5Pom  
output.close(); o-cAG{.WC  
} g_Im;1$  
catch(IOException e){e.printStackTrace ();} =@)d5^<5F  
catch(Exception e){e.printStackTrace ();} wIf {6z{  
} ,]5Ic.};p  
_xLHrT!y  
Y+qQIMZ  
//读取保存的下载信息(文件指针位置) =\{\g7  
private void read_nPos() j8K,jZ  
{ X o{`]  
try{ #*>E*#?t  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ! <WBCclX  
int nCount = input.readInt(); ,Os? f:Y6  
nStartPos = new long[nCount]; 7zTqNnPnf  
nEndPos = new long[nCount]; p*l$Wj  
for(int i=0;i<nStartPos.length;i++) F6hmku>\1  
{ A!63p$VT;  
nStartPos = input.readLong(); )J(q49  
nEndPos = input.readLong(); .4l/_4,s_  
} #Z~C`n u  
input.close(); %5\3Aw  
} [= "r<W0  
catch(IOException e){e.printStackTrace ();} %/.a]j!  
catch(Exception e){e.printStackTrace ();} ,pBh`av  
} T$= 4O9G  
Q7bq  
pA4*bO+  
private void processErrorCode(int nErrorCode) ]h9!ei [  
{ QjPj[c  
System.err.println("Error Code : " + nErrorCode); $t-n'Qh^2  
} jtm?z c  
]8;n{ }X  
N:"C+ a(  
//停止文件下载 ~}DQT>7$  
public void siteStop() >`jU`bR@  
{ T5O _LCIws  
bStop = true; NcM>{{8  
for(int i=0;i<nStartPos.length;i++) bY~@}gC**@  
fileSplitterFetch.splitterStop(); rx:z#"?I  
bqx0d=Z~[  
l?*r5[O>n  
} OJ4SbI  
} Wn|&cG9  
//负责部分文件的抓取 iK_c.b  
**FileSplitterFetch.java 5y4u5Tm-%  
*/ y/c%+ Ca/  
package NetFox; kWj \x|E  
,572n[-q  
X%9*O[6{  
import java.io.*; 4F MAz^  
import java.net.*; i.1U|Pi  
DDd|T;8  
 StYzGJ  
public class FileSplitterFetch extends Thread { VK3it3FI>3  
o5aLU Wi-  
c3 &m9zC  
String sURL; //File URL SNT5Amz!  
long nStartPos; //File Snippet Start Position T{vR,  
long nEndPos; //File Snippet End Position iwY'4 Z e  
int nThreadID; //Thread's ID YW; Hk1  
boolean bDownOver = false; //Downing is over N6Z{BLZ  
boolean bStop = false; //Stop identical P|jF6?C  
FileAccessI fileAccessI = null; //File Access interface vs&8wbS)  
_U)%kY8  
i z]rFNR  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException rSV gWr8  
{ !Ngw\@f  
this.sURL = sURL; KbxR Lx]w  
this.nStartPos = nStart; xU9@$am  
this.nEndPos = nEnd; H]#Rg`~n  
nThreadID = id; 5c -N0@\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (S^ck%]]a!  
} EqM;LgE=  
F:37MUQi  
2)/NFZ  
public void run() g\M5:Qm  
{ `^U&#K  
while(nStartPos < nEndPos && !bStop) XT@Mzo49z\  
{ '7I g.K&  
}{],GHCjQ  
G\iyJSj[P  
try{ G { mC7@  
URL url = new URL(sURL); v vE\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `3iQZu i  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1x >iz `A  
String sProperty = "bytes="+nStartPos+"-"; KhM.Tc  
httpConnection.setRequestProperty("RANGE",sProperty); :]eb<J  
Utility.log(sProperty); QYThW7S  
~S(^T9R  
mgkyC5)d  
InputStream input = httpConnection.getInputStream(); pvXcLR)L+3  
//logResponseHead(httpConnection); ^i_Iqph=  
{8NwFN.  
3#.\  
byte[] b = new byte[1024]; XrN- 2HTV  
int nRead; ms~8QL  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :mv`\  
{ _dU P7H (  
nStartPos += fileAccessI.write(b,0,nRead); Nf?\AK!  
//if(nThreadID == 1) LAZVW</  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [>w%CY<Fd  
} 5 d ;|=K  
r[HT9  
w+f=RHX"{  
Utility.log("Thread " + nThreadID + " is over!"); O]nT>;PXX  
bDownOver = true; E8/rZ~0O~  
//nPos = fileAccessI.write (b,0,nRead); ehOs9b  
} ^b53}f8H  
catch(Exception e){e.printStackTrace ();} xFsmf<Vm  
} %cW;}Y[?P  
} J4yt N3  
QB1M3b  
Q_}/ Pn$1  
//打印回应的头信息 ; Zq/eiB  
public void logResponseHead(HttpURLConnection con) }e=e",eAT  
{ zLek& s&-  
for(int i=1;;i++) C+l?k2  
{ HZ\k-!2  
String header=con.getHeaderFieldKey(i); ~b8a^6:R"  
if(header!=null) ]C *10S`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Q\#UWsN(T/  
Utility.log(header+" : "+con.getHeaderField(header)); `fW{yb  
else \p6 }  
break; v["3  
}  wOHEv^,  
} :t2B^})\  
/PC` 0/b  
#%cR%Z  
public void splitterStop() jzrt7p*k}  
{ 6An{3 "  
bStop = true;  `$-lL"  
} RG? MRxC  
rl|Q)A{  
ahp1!=Z-=  
} u33zceE8  
K^ 6+Ily  
@+dHF0aXd  
/* p\+6"28{_~  
**FileAccess.java pF='jj51  
*//文件访问(定位,写) pbdF]>\  
package NetFox; #`j][F@N  
import java.io.*; 2nx9#B*/T  
vPsq<l}  
L<)Z>@fR  
public class FileAccessI implements Serializable{ }jcIDiSu  
Opry`}5h  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (rMZ  
RandomAccessFile oSavedFile; 2f`xHI/@fj  
long nPos; >a9l>9fyY  
73pC  
[|<EDR  
public FileAccessI() throws IOException yjeL9:jH[  
{ .93S>U<_  
this("",0); YOKR//|3  
} ,TJ/3_lH  
^^ j/  
h60\ Y 8  
public FileAccessI(String sName,long nPos) throws IOException DvJB59:_}  
{ M8Juykw  
oSavedFile = new RandomAccessFile(sName,"rw"); s*+ZYPk  
this.nPos = nPos; 2+&R" #I  
oSavedFile.seek(nPos); .~22^k  
} )rbc;{.  
9,KVBO  
{]@Qu"M  
public synchronized int write(byte[] b,int nStart,int nLen) kDg{ >mf  
{ <THUsY`3P&  
int n = -1; H8<m9zDvl  
try{ NlMQHma  
oSavedFile.write(b,nStart,nLen); s+N^PX3  
n = nLen; tgfM:kzw  
} 1{7_ `[  
catch(IOException e) L77EbP`P  
{ }JH`' &3  
e.printStackTrace (); v0u\xX[H;  
} {N Y]L==H  
8k%H[Smn:  
"& Ff[ O*  
return n; G ;jF9i  
} 5{HtJ?sKc5  
-P*xyI  
p/4S$ j#Tn  
} \ bC}&Iz6  
sD.6"w7}  
.oEFX8  
/* "u,sRbL  
**SiteInfoBean.java <gR`)YF7  
*/ ~X[S<Gi#  
package NetFox; V!H(;Tuuo  
6,a%&1_  
z,M'Tr.1|  
public class SiteInfoBean { v<%]XHN  
|zT%$  
Mo~ki"9.  
private String sSiteURL; //Site's URL ?C FS}v  
private String sFilePath; //Saved File's Path (}sDm ~;s  
private String sFileName; //Saved File's Name Wf_CR(  
private int nSplitter; //Count of Splited Downloading File { _-wG3f|  
m&,bC)}  
#i@ACAgn;6  
public SiteInfoBean() zLo;.X[Y  
{//nSplitter的缺省值为5 }z8{B3K  
//default value of nSplitter is 5 vT&j{2U7XW  
this("","","",5); w< v1 N  
} uSH> $;a  
aX:#'eDB  
i1tVdbC]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u mqLKf=x!  
{ `:V}1ioX5  
sSiteURL= sURL; 4,gol?a  
sFilePath = sPath; { ( _B  
sFileName = sName;  4c  
this.nSplitter = nSpiltter; VjC*(6<Gj  
.@fK;/OuC  
vU?b"n  
} P"oYC$  
mJSK; @w<O  
Fecx';_1`  
public String getSSiteURL() a|8| @,  
{ r9+E'\  
return sSiteURL; w:ORmR .p  
} F\o;t:  
E]e, cd  
X!HDj<  
public void setSSiteURL(String value) @^'G&%j  
{ (Nm}3p  
sSiteURL = value; S`ax*`  
} 6F@zCv"w  
 $&ex\_W  
^2C0oX  
public String getSFilePath() pg} ~vb"  
{ UOn!Y@  
return sFilePath; BM|-GErE  
} I{`KKui<M  
*p""YEN  
83{x"G3>  
public void setSFilePath(String value) $ /}:P  
{ X{5v?4wI  
sFilePath = value; ~AEqfIx*^&  
} [ c ~LY4:  
h5LJij J  
f}L>&^I)  
public String getSFileName() 2neF<H?^o  
{ \e`6=Q%  
return sFileName; r24\DvS  
} A6@+gP<  
)ZS:gD  
<Cf7E  
public void setSFileName(String value) ;J,,f1Vw  
{ ]7#^])>  
sFileName = value; OhSt6&+  
} iFAoAw(  
"-0pz\a  
gt2>nTJz.Z  
public int getNSplitter() b9W<1eqF  
{ V\iIvBpWg  
return nSplitter; j6&zRFX  
} n.Ur-ot  
9J-!o]f .b  
/{eih]`x(  
public void setNSplitter(int nCount) ;[WSf{k  
{ oW yN:Qh  
nSplitter = nCount; 6nY )D6$JG  
} ]X >QLD0W  
} Q7 0**qm  
zVc7q7E  
eI/\I:G{f  
/* }\PE {  
**Utility.java e B(S+p?  
*/ ?c=R"Yg$  
package NetFox; 'y+bx?3Z  
J^s<x#C  
O5G<O(,\  
public class Utility { RAD4q"}k  
8 ACY uN\  
@MlU!oR&  
public Utility() W[1f]w3  
{ V:0uy>  
= h<? /Krs  
Rktn/Vi  
} xu_XX#9?b  
:YRzI(4J  
//线程睡眠 JucxhjV#,  
public static void sleep(int nSecond) {P<BJ52=  
{ [F AOp@7W  
try{ 7fN&Q~.  
Thread.sleep(nSecond); jnU*l\,  
} XTi0,e]5{u  
catch(Exception e) Sf4h!ly  
{ }VGI Y>v  
e.printStackTrace (); P/gb+V=g!  
} iRj x];:Vu  
} 0oi5]f6g?8  
LO$#DHPt  
//日志 xo)?XFM2  
public static void log(String sMsg) YCB 3  
{ jB/q1vFO  
System.err.println(sMsg); bKt3x+x(  
} O%++0k;  
u>Axq3F  
A^r [_dyZ  
public static void log(int sMsg) XvzV lKL  
{ sA j$U^Gp  
System.err.println(sMsg); a[#BlH  
} ~_6rD`2cJ  
} $(hZw  
\EqO;A%<  
'7%9Sqx  
/* of<OOh%3  
**TestMethod.java 8;bOw  
*/ a#@ opUn-  
package NetFox; RR9s%>^  
;0WlvKF  
<Z wEdq  
public class TestMethod { #7)6X:/O  
zoXF"Nz  
aUQq<H'R  
public TestMethod() #]a0 51Y  
{ ///xx/weblogic60b2_win.exe Z r*ytbt  
try{ YI/vt2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >8c9-dTmf  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *e=e7KC6kI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6N ^FJCs  
fileFetch.start(); v "07H  
} NB[b[1 Ch  
catch(Exception e){e.printStackTrace ();} U-(d~]$  
d+kIof,  
7_LE2jpC,5  
} %~@}wHMB  
o Vs&r?\Z  
V@F~Cx  
public static void main(String[] args) <D?`*#K  
{ q;U[f6JjE  
new TestMethod(); ?6|EAKJ`lK  
} 16AYB17  
} 3>Yec6Hs  
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