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http断点续传简单实现(java)

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/* ;<A/e  
**SiteFileFetch.java DPOPRi~  
*/ Ah`dt8t  
package NetFox; 4@I]PG  
import java.io.*; EUkNh>U?  
import java.net.*; =)8Ct  
g]#Wve  
_;{-w%Vf  
public class SiteFileFetch extends Thread { i]z i[Zo$  
h(-&.Sm")H  
Q/9b'^UJ  
SiteInfoBean siteInfoBean = null; //文件信息Bean Q:\hh=^  
long[] nStartPos; //开始位置 _1'Pb/1  
long[] nEndPos; //结束位置 Tjqn::~D  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 bph*X{lFK  
long nFileLength; //文件长度 M}Mzm2d#`  
boolean bFirst = true; //是否第一次取文件 4;||g@f'[  
boolean bStop = false; //停止标志 ?s]`G'=>V`  
File tmpFile; //文件下载的临时信息 JPG!cX%  
DataOutputStream output; //输出到文件的输出流 4/?Zp4g  
)QD}R36Ic  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `9l\ ~t(M  
public SiteFileFetch(SiteInfoBean bean) throws IOException o{p_s0IX;S  
{ 3XtGi<u  
siteInfoBean = bean; @U JmbD{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &?6w 2[}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \tx/!tA  
if(tmpFile.exists ()) { )qP34rM  
{ ~tvoR&{I  
bFirst = false; ~~,<+X:  
read_nPos(); >lmL  
} P1n@E*~V5  
else _O%p{t'q<  
{ DG=Ap:sl*$  
nStartPos = new long[bean.getNSplitter()]; h :R)KM  
nEndPos = new long[bean.getNSplitter()]; rUjr'O0  
} Pa +BE[z  
D$E9%'ir  
`t&;Yk]-L  
C 5 UDez  
} S+Yg!RrNqj  
;g jp&g9Q  
[@Y q^.6t  
public void run() C6~dN& q  
{ bobkT|s^s  
//获得文件长度 I:<R@V<~#  
//分割文件 m=B0!Z1xx  
//实例FileSplitterFetch ?y)X$D^  
//启动FileSplitterFetch线程 9K<a}QJP  
//等待子线程返回 eB*8)gYh  
try{ ;r"B?]JO  
if(bFirst) |$2N$6\SP  
{ J *?_SnZ  
nFileLength = getFileSize(); Vz]=J;`Mz  
if(nFileLength == -1) 5i#w:O\cz  
{ ^^l"brPa  
System.err.println("File Length is not known!"); h+D=/:B  
} YWrY{6M  
else if(nFileLength == -2) .`N` M9  
{ {1|7N GQ  
System.err.println("File is not access!"); ZF (=^.gc  
} V JL;+  
else W2h[NimU  
{ (t$/G3E  
for(int i=0;i<nStartPos.length;i++) cV,Dl`1r  
{ 1C=P#MU`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); FSs$ ] d;  
} &Ld8Z9IeFp  
for(int i=0;i<nEndPos.length-1;i++) WI_mJ/2  
{ ]_8I_V cQ  
nEndPos = nStartPos[i+1]; `0|&T;7  
} L$ Ar]O)  
nEndPos[nEndPos.length-1] = nFileLength; JSK5x(GlH  
} -U[`pUY?f  
} y|{?>3  
\'Kj.EO{?$  
#`0z=w/)  
//启动子线程 ya g  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; TR_oI<xB2  
for(int i=0;i<nStartPos.length;i++) ItE~MJ5p  
{ a' o8n6i  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), = [os<+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), h\\2r>  
nStartPos,nEndPos,i); Q$/FgS  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "0zXpQi,B  
fileSplitterFetch.start(); M|e n>P  
} (Gc`3jJ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =3dbw8I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <|Eby!KXR  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |S`yXsg  
nEndPos = " + nFileLength); 9R"N#w.U]  
// fileSplitterFetch[nPos.length-1].start(); <L/vNP  
sNmC#,  
p+UHJ&  
//等待子线程结束 <JM%Kn )  
//int count = 0; F6]!?@  
//是否结束while循环 4~YQ\4h=  
boolean breakWhile = false; Prz +kPP  
P Xn>x8z  
1'm`SRX#e  
while(!bStop) PFgjWp"Y  
{ l'". }6S  
write_nPos(); QYw4kD}  
Utility.sleep(500);  >E ;o"  
breakWhile = true; /M*\t.[ 46  
8;f<qu|w  
T-2p`b}h W  
for(int i=0;i<nStartPos.length;i++) o\;"|O}  
{ N<"6=z@w+  
if(!fileSplitterFetch.bDownOver) dQ`ZrWd_U  
{ )wzs~Fn/  
breakWhile = false; c&?a ,fpb  
break; tSc>@Q_|  
} r9a!,^}F  
} '# IuY  
if(breakWhile) !vVjZ  
break; p2DNbY\]  
as |c`4r\O  
Y1aF._Z  
//count++; `=$jc4@J  
//if(count>4) hIo S#]  
// siteStop(); ^npS==Y]!.  
} I+j|'=M  
fZ~kw*0*  
vp75u93  
System.err.println("文件下载结束!"); 2n;;Tso"  
} \{=`F`oB=  
catch(Exception e){e.printStackTrace ();} xgqv2s>L  
} uQtk|)T E  
dzE Q$u/I  
?$@ KwA  
//获得文件长度 E(3+o\w  
public long getFileSize() &G|jzXE  
{ 6O@ ^`T  
int nFileLength = -1; m#'rI=}!  
try{ |U$de2LF  
URL url = new URL(siteInfoBean.getSSiteURL()); ecqz@*d&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); HZ<f(  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^r$iN %&~  
""v`0OP&J  
c]!D`FA*K  
int responseCode=httpConnection.getResponseCode(); R ms01m>Y  
if(responseCode>=400) s.I1L?s1w?  
{ pM'IQ3N  
processErrorCode(responseCode); 5v>{Z0TE[6  
return -2; //-2 represent access is error &J/4J  
} 3auJ^B}  
9H, &nET  
CBnouKc:  
String sHeader; .Lr)~  
~eV!!38 J  
CNRU"I+jU  
for(int i=1;;i++) xAd>",=~  
{ s3_e7D ^H  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); PVS<QN%  
//Utility.log(in.readLine()); ) 4L%zl7  
sHeader=httpConnection.getHeaderFieldKey(i); :_QAjU  
if(sHeader!=null) ['Y+z2k  
{ uJ/?+5TU  
if(sHeader.equals("Content-Length")) 5ih"Nds[H  
{ !ga (L3vf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :OQ:@Yk  
break; $,QpSK`9i  
} bu"68A;>  
} ic0v*Y$  
else ,+f0cv4  
break; m~j\?mb{+  
} 7=p-A _X  
} 'D0X?2  
catch(IOException e){e.printStackTrace ();} M$]O=2h+2  
catch(Exception e){e.printStackTrace ();} Neo^C_[vN  
rv%ye H  
x#j\"$dla  
Utility.log(nFileLength); *n*N|6 +  
PZ!dn%4jy  
#?$'nya*u  
return nFileLength; X# kjt )W  
} ZP6 3Alt  
o ,Tr^e$  
_+Jf.n20  
//保存下载信息(文件指针位置) EB29vHAt~  
private void write_nPos() dp[w?AMhM9  
{ e:GgA  
try{ ^`jZKh8)h  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ;&W;  
output.writeInt(nStartPos.length); fr'huvc  
for(int i=0;i<nStartPos.length;i++) Hr<C2p^a  
{ -wf RR>)d  
// output.writeLong(nPos); @( n^S?(  
output.writeLong(fileSplitterFetch.nStartPos); 16[-3cJ T  
output.writeLong(fileSplitterFetch.nEndPos); :B*vkwT  
} ^QXw[th!d  
output.close(); C7jc6(> m  
} JwI`"$ > w  
catch(IOException e){e.printStackTrace ();} ANFg]g.Az  
catch(Exception e){e.printStackTrace ();} 7dlKdKH  
} C'8!cPFVv  
EOBs}M;  
sR>`QIi(a  
//读取保存的下载信息(文件指针位置) m,@1LwBH  
private void read_nPos() orB8Q\p'  
{ KCJN<  
try{ L*UV  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~ gfA](N  
int nCount = input.readInt(); :zj9%4A  
nStartPos = new long[nCount]; 2-$bh  
nEndPos = new long[nCount]; I NPYJ#%  
for(int i=0;i<nStartPos.length;i++) ^)hAVf~E  
{ @m/;ZQ  
nStartPos = input.readLong(); #j^('K|  
nEndPos = input.readLong(); >9.5-5"   
} Wiq{wxe  
input.close(); 4{*tn"y  
} |ilv|UV  
catch(IOException e){e.printStackTrace ();} L8bI0a]r"*  
catch(Exception e){e.printStackTrace ();} OBI+<2`Oc  
} EREolCASb  
+-H}s`  
43J\8WBn@  
private void processErrorCode(int nErrorCode) $c@w$2  
{ 83  i1  
System.err.println("Error Code : " + nErrorCode); `sk!C7%  
} q6C6PPc  
m1hW<  
u( 1J=h  
//停止文件下载 2<[ eD`u  
public void siteStop() N>A{)_k3  
{ 9@#h}E1$  
bStop = true; QM[A;WBr7  
for(int i=0;i<nStartPos.length;i++) })o~E  
fileSplitterFetch.splitterStop(); q:Y6fbt<7  
CYPazOfj  
2ec$xms  
} t_I\P.aMA  
} *t#s$Ga  
//负责部分文件的抓取 A$%Q4jC}  
**FileSplitterFetch.java >Lw}KO`  
*/ \);.0  
package NetFox; VX^o"9Ntl  
49+ >f  
p{ @CoOn  
import java.io.*; )YzHk ;(  
import java.net.*; XMN?;Hj>  
fg9?3x Z  
JJ/1daj  
public class FileSplitterFetch extends Thread { 0T9@,scY  
Dd!Sr8L[  
f {y]  
String sURL; //File URL /OQK/ t63  
long nStartPos; //File Snippet Start Position $ ^W-Wmsz  
long nEndPos; //File Snippet End Position F . K2  
int nThreadID; //Thread's ID "t[M'[ `C  
boolean bDownOver = false; //Downing is over On{~St'V  
boolean bStop = false; //Stop identical !;o\5x<'$O  
FileAccessI fileAccessI = null; //File Access interface 24T@N~\g  
QU^/[75Ea0  
xab]q$n]k  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *2JH_Cj`  
{ o {=qC:b  
this.sURL = sURL; ?xtt7*'D  
this.nStartPos = nStart; kAZC"qM%i  
this.nEndPos = nEnd; *:=];1 O  
nThreadID = id; UGhW0X3k  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  }Vvsh3  
} "sF Xl  
D9qX->p  
Qs|OG  
public void run() _Kc 1  
{ )\{'fF  
while(nStartPos < nEndPos && !bStop) IK*oFo{C=K  
{ Y%<`;wK=^  
UF@IBb}0  
#*!+b  
try{ t *{,Gk  
URL url = new URL(sURL); ![^EsgEB*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %ZujCZn  
httpConnection.setRequestProperty("User-Agent","NetFox"); _9D|u<D  
String sProperty = "bytes="+nStartPos+"-"; 9pWi.J  
httpConnection.setRequestProperty("RANGE",sProperty); #F_'}?09%  
Utility.log(sProperty); Dn~Z SrJ  
 f>.4-a?  
[f<"p[  
InputStream input = httpConnection.getInputStream(); q1YLq(e  
//logResponseHead(httpConnection); U?bG`. X  
c]A Y  
IE&_!ce  
byte[] b = new byte[1024]; ?22d},.  
int nRead;  X ?tj$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o_iEkn  
{ pG/ NuImA  
nStartPos += fileAccessI.write(b,0,nRead); ]]>nbgGn#  
//if(nThreadID == 1) tf4*R_6;1$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ecn}iN  
} :/+>e IE  
B;VH`*+X  
>&bv\R/  
Utility.log("Thread " + nThreadID + " is over!"); Rr%tbt.sE  
bDownOver = true; $bk>kbl P  
//nPos = fileAccessI.write (b,0,nRead); \X&]FZ(*  
} @u,+F0Yd  
catch(Exception e){e.printStackTrace ();} KwS`3 6:  
} zQ,f5x  
} m&Lt6_vi  
Z.!g9fi8>  
#nKRTb+{  
//打印回应的头信息 g^1r0.Sp{8  
public void logResponseHead(HttpURLConnection con) S|HY+Z6n'  
{ Ba<ngG !  
for(int i=1;;i++) / T ,zZ9=  
{ z VdKYs i^  
String header=con.getHeaderFieldKey(i); l1&5uwuF  
if(header!=null) 4<u;a46Z#M  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); : (cb2j(C  
Utility.log(header+" : "+con.getHeaderField(header)); :3v9h^|+  
else V|TA:&:7  
break; z;J  
} H ZPcd_(  
} L^lS^P  
GE@uO J6H  
Qh^R Ax  
public void splitterStop() /mc*Hc 8R8  
{ dgXg kB'  
bStop = true; ] GNh)  
} I-,>DLG  
i<mevL  
3c b[RQf  
}  ozU2  
/J;;|X#P  
{B3(HiC  
/* 6#E7!-u(-  
**FileAccess.java yr5NRs  
*//文件访问(定位,写) aVP5%  
package NetFox; ,(P %z.P@  
import java.io.*; *%X.ym'  
T8U[xu.>  
l8^y]M  
public class FileAccessI implements Serializable{ (v!mR+\x  
x@Y|v@}BE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 gV|Y54}T  
RandomAccessFile oSavedFile; |~eY%LB  
long nPos; L;3aZt,#O  
[<yz)<<  
PB+\jj  
public FileAccessI() throws IOException G.Tpl-m  
{ !3h{lE B  
this("",0); Je^Y&a~  
} *<r%aeG$em  
|CwG3&8  
N+NK`  
public FileAccessI(String sName,long nPos) throws IOException BhLZ7*  
{ ^#;RLSv   
oSavedFile = new RandomAccessFile(sName,"rw");  //<:k8  
this.nPos = nPos; p5-<P?B  
oSavedFile.seek(nPos); `gI~|A4  
} pw3 (t  
S;8.yj-  
6}ftBmv  
public synchronized int write(byte[] b,int nStart,int nLen)  ;1@C_5C  
{ ';6X!KY+]  
int n = -1; q[P~L`h S  
try{ -KiRj!v|  
oSavedFile.write(b,nStart,nLen); + 8f>^*:u  
n = nLen; 2 5Q+1  
} @V$I?iXV  
catch(IOException e) &$F[/[Ds+  
{ -D#5o,]3  
e.printStackTrace (); @bT3'K-4  
} dQ<(lzS~  
g5}lLKT  
]YsR E>  
return n; T`?n,'!(  
} @^!\d#/M  
\!<"7=(J{4  
b/nOdFO@  
} wWTQ6~Y%d  
y@A6$[%(E|  
^X &)'H  
/* &dRjqn^&X  
**SiteInfoBean.java b66R}=P l  
*/ [/OQyb4F<  
package NetFox;  , ]7XMU3  
&2{]hRM  
c|lU(Tf  
public class SiteInfoBean { j&CZ=?K^c  
q`^3ov^</  
WYLX?x  
private String sSiteURL; //Site's URL >)^N J2Fd  
private String sFilePath; //Saved File's Path < Y>3  
private String sFileName; //Saved File's Name o8{<qn|  
private int nSplitter; //Count of Splited Downloading File W`x)=y]Z  
1~@|e Wr|  
)~}PgbZ^  
public SiteInfoBean() +9zA^0   
{//nSplitter的缺省值为5 ~KRnr0  
//default value of nSplitter is 5 ~C| ,b"  
this("","","",5); E0YU[([G  
}  eu9w|g  
@6b[GekZ<  
Q>=-ext}q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *H" aOT^{  
{ y9!:^kDI  
sSiteURL= sURL; ;Iq5|rzDn  
sFilePath = sPath; K_#UZA< Y  
sFileName = sName; uN bIX:L,  
this.nSplitter = nSpiltter; {y6C0A*  
-!TcQzHUs  
D0ruTS  
} TsD;Kl1  
A"4@L*QV  
3ji:O T  
public String getSSiteURL() + |C=ZU  
{ .S_QQM}Q  
return sSiteURL; U5<@<j(@  
} o/1JO_41  
RZh}:  
(6R4 \8z2  
public void setSSiteURL(String value) &@6 GI<  
{ g$w6kz_[  
sSiteURL = value; A(+:S"|@  
} ;SY.WfVA7  
e+@xs n3  
QNArZ6UQ  
public String getSFilePath() ,|pp67  
{ t$ZkdF  
return sFilePath; J3=BE2L  
} *1bzg/T<  
)GJP_*Ab  
Qh-4vy =r  
public void setSFilePath(String value) m7m \`;  
{ cPuHLwwYf  
sFilePath = value; e$wt&^W  
} |<(t}}X  
XLb0 9;  
tjxvN 4l  
public String getSFileName() C:GvP>  
{ Qq3fZ=  
return sFileName; `6F +Rrn  
} w$>3pQ8d  
jBpVxv  
}OrYpZob  
public void setSFileName(String value) /DO'IHC.o  
{ UX_I6_&  
sFileName = value; zfjw;sUX  
} 3LW[H+k  
>a=d;  
>^3zU   
public int getNSplitter() >nry0 ;z0,  
{ +'XhC#:  
return nSplitter; l^r' $;<m  
} Mr* |9h  
S$O,] @)  
2EfflZL3  
public void setNSplitter(int nCount) "HC)/)Mv@  
{ c7qwNs*f  
nSplitter = nCount; @~o`#$*|  
} 3eKQ<$w  
} }q'WC4.  
GuO`jz F  
wiE]z  
/* yd>}wHt  
**Utility.java ?/d!R]3  
*/ wL2XNdo}<  
package NetFox; l!IGc:  
``9 GY  
^,V[nfQR  
public class Utility { Q4wc-s4RN  
#T\  
%&<W(|U1<  
public Utility() o:UXPAj  
{ `^##b6jH  
te'*<HM  
|4Ha?W  
} s'L?;:)dyB  
a+?~;.i~  
//线程睡眠 'm O2t~n  
public static void sleep(int nSecond) )( bxpW  
{ j}RzXJ~t  
try{ T~s}Nx#  
Thread.sleep(nSecond); yVS\Q,:J9  
} sKfXg`0  
catch(Exception e) wFL3& *  
{ cOku1 g8  
e.printStackTrace (); 70Ka!  
} 3ATjsOL  
} " s]y!BLk  
>&Fa(o;*  
//日志 NHiq^ojk  
public static void log(String sMsg) m mw-a0  
{ 6c<ezEJ  
System.err.println(sMsg); Q6^x8  
} 6fwY$K\X  
T=\!2gt  
~HDdO3  
public static void log(int sMsg) Np)aS[9W  
{ dWR1cvB(wY  
System.err.println(sMsg); HomN/wKh  
} >. LKct*5K  
} l`gTU?<xd  
]}LGbv"`A  
xjq0D[  
/* 2P5_zND  
**TestMethod.java _e'Y3:  
*/ {4rQ7J4Ux  
package NetFox; jJ++h1 K  
qtzRCA!9(Z  
{L0;{  
public class TestMethod { ^?"^Pmw  
zk=\lp2  
r4;Bu<PQN1  
public TestMethod() !T'X 'Q  
{ ///xx/weblogic60b2_win.exe nq;#_Rkr  
try{ X~RH^VYv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); z\.1>/Z=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); nyhMnp#<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z $6JpG  
fileFetch.start(); C6@t  
} 'IQsve7cI  
catch(Exception e){e.printStackTrace ();} xb$yu.c  
.>]N+:O  
OVswt  
} dZ2`{@AYY  
8$}OS-  
Oif,|:  
public static void main(String[] args) Vxh.<b6&'  
{ [Ox(.  
new TestMethod(); Y<LNQ]8\G  
} h&'=F)5  
} 1D{#rA.X  
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