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http断点续传简单实现(java)

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/* I<&) P#"  
**SiteFileFetch.java ~MK%^5y?  
*/ $C{-gx+:  
package NetFox; ]PH'G>x  
import java.io.*; 9$R}GK  
import java.net.*; )*BG-nM u  
Uo:=-NNI  
CY@#_z  
public class SiteFileFetch extends Thread { Q\le3KB  
#.@D}7y5  
kbx4I?  
SiteInfoBean siteInfoBean = null; //文件信息Bean al]-*=v7}  
long[] nStartPos; //开始位置 Cj6$W5I m  
long[] nEndPos; //结束位置 thh0~g0/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >\1j`/ :ZI  
long nFileLength; //文件长度 [@$t35t~  
boolean bFirst = true; //是否第一次取文件 7t% |s!~  
boolean bStop = false; //停止标志 U ,\t2z  
File tmpFile; //文件下载的临时信息 |198A,^  
DataOutputStream output; //输出到文件的输出流 bqZ5GKUo  
[_tBv" z  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) mw${3j~&  
public SiteFileFetch(SiteInfoBean bean) throws IOException N*}g+ IS  
{ Y c>.P  
siteInfoBean = bean; `Y<FR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); mx0EEU*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Fau24-g  
if(tmpFile.exists ()) GUvEOD=p  
{ E$5A 1  
bFirst = false; h`MTB!o  
read_nPos(); ShU1RQk  
} =?1B|hdo  
else '!XVz$C  
{ GaOM|F'>  
nStartPos = new long[bean.getNSplitter()]; lMb&F[KJ7  
nEndPos = new long[bean.getNSplitter()]; EUuk%<q7C(  
} 3ZL<6`YF  
AbOF/ g)C  
iq`caoi  
5wm(gF_t  
} ;v%f +  
}m.45n/  
>B+!fi'SS>  
public void run() t`"pn <  
{ qbD[<T  
//获得文件长度 IFW"S fdZk  
//分割文件 :sJQ r._L  
//实例FileSplitterFetch $36.*s m  
//启动FileSplitterFetch线程 P^m&oH5]EG  
//等待子线程返回 _G ^Cc}X  
try{ 0hOps5c8=  
if(bFirst) h5 PZ?Zd  
{ !TPKD  
nFileLength = getFileSize(); <2fgao&-n  
if(nFileLength == -1) oYrg;]H  
{ A0gRX]  
System.err.println("File Length is not known!"); )s>R~7  
} *f3? 0w  
else if(nFileLength == -2) 3 V0^v  
{ :$&v4IW  
System.err.println("File is not access!"); c#`&uLp  
} lw_PQ4Hp  
else qPgny/(  
{ {*K7P>&  
for(int i=0;i<nStartPos.length;i++) *w23(f  
{ X~ g9TUv8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); qW|_|%{U+  
} !4(QeV-=  
for(int i=0;i<nEndPos.length-1;i++) 1R7w  
{ cP >[H:\Xc  
nEndPos = nStartPos[i+1]; a3SBEkC  
} Q-y`IPtA<  
nEndPos[nEndPos.length-1] = nFileLength; J*+[?FXRL  
} jF0>w  m  
} 2 UPG8]  
-5#cfi4^*  
! +XreCw  
//启动子线程 F4 =V* /7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I@:"Qee  
for(int i=0;i<nStartPos.length;i++) :r}C&3  
{ ~Nn}FNe  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #7p!xf^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), oR'u&\mB  
nStartPos,nEndPos,i); ^BhS*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }sW%i#CV  
fileSplitterFetch.start(); t-)d*|2n}o  
} ygYy [IZ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J)P7QTC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); QeG3X+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,d$D0w  
nEndPos = " + nFileLength); #.@-ng6C  
// fileSplitterFetch[nPos.length-1].start(); o8u;2gZx  
X \qG WpN%  
8 Cw3b\ne  
//等待子线程结束 Tx|y!uHh  
//int count = 0; }mOo=)C!  
//是否结束while循环 gvoYyO#cm  
boolean breakWhile = false; `zsooA Gt  
eR:C?v  
W7"UhM  
while(!bStop) u Fn?U)  
{ #N;McF;W  
write_nPos(); R0YWe  
Utility.sleep(500); K#xL-   
breakWhile = true; 2$FH+wuW  
t"jiLOQ[6  
D4$2'h  
for(int i=0;i<nStartPos.length;i++) /o9 0O&  
{ l;}3J3/qq]  
if(!fileSplitterFetch.bDownOver) W}@IUCRs  
{ q@vqhE4  
breakWhile = false; jR>`Xz  
break; -.l.@  
} Q2<v: *L  
} %#C9E kr  
if(breakWhile) K>G.HN@  
break; h`f$]_c  
Ik-E_U2  
fw)Q1"|  
//count++; D 3Tqk^5  
//if(count>4) rG3?Z^&R+  
// siteStop(); moL3GV%]Gq  
} 5:(/k\9+yv  
"<&) G{  
DcN!u6sJ  
System.err.println("文件下载结束!"); ~]SCf@pRk  
} DGNn#DP  
catch(Exception e){e.printStackTrace ();} P=R-1V  
} D.gD4g_O/  
!wTrWD!  
-quJX;~  
//获得文件长度 2@Oz_?O=  
public long getFileSize() J;'H],w}f  
{ ]EdZ,`B4  
int nFileLength = -1; B_ bZa  
try{ &cwN&XBY  
URL url = new URL(siteInfoBean.getSSiteURL());  C=qL0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ch33+~Nn  
httpConnection.setRequestProperty("User-Agent","NetFox"); $ i%#fN  
{@hJPK8  
8J:=@X^}  
int responseCode=httpConnection.getResponseCode(); % _nmv  
if(responseCode>=400) D~n-;T  
{ d .%2QkL  
processErrorCode(responseCode); Yz#E0aTTA  
return -2; //-2 represent access is error _ Y7 Um  
} g)7@EU2  
X0]{8v%  
~ +h4i'  
String sHeader; <!F".9c@A  
8*Ty`G&v  
vIf-TQw  
for(int i=1;;i++) !,]2.:{0z  
{ c#TV2@   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U9jdb9 |  
//Utility.log(in.readLine()); {.ypZ8JU  
sHeader=httpConnection.getHeaderFieldKey(i); (__$YQ-  
if(sHeader!=null) {vdY(  
{ \ &47u1B  
if(sHeader.equals("Content-Length")) $gZiW8  
{ =\G`g #  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~RLWr.pK  
break; @0(%ayi2Y  
} y?U@F/^}N  
} FC WF$'cO  
else F}=_"IkZ  
break; udmLHc  
} n|Ts:>`V  
} %xr'96d  
catch(IOException e){e.printStackTrace ();} _0UE*l$t  
catch(Exception e){e.printStackTrace ();} =J|jCK[r  
BS(jC  
\Foo:jON  
Utility.log(nFileLength); m^ Epw4eg  
%7QSBL  
m_.9 PZ  
return nFileLength; L/In~' *-  
} W]XM<# ^^  
2_ 1RJ  
[w!T  
//保存下载信息(文件指针位置) iiF`2  
private void write_nPos() +*,!q7Gt  
{ {Q c,Nl [?  
try{ xojt s;n   
output = new DataOutputStream(new FileOutputStream(tmpFile)); Mdq|: ^px  
output.writeInt(nStartPos.length); Z_fwvcZ?05  
for(int i=0;i<nStartPos.length;i++) P^!g0K  
{ w 62m}5eA  
// output.writeLong(nPos); eK5~YM:o  
output.writeLong(fileSplitterFetch.nStartPos); %|D) U>o{  
output.writeLong(fileSplitterFetch.nEndPos); -}PE(c1%?q  
} #RbdQH !  
output.close(); mG$N%`aG  
} l(Dr@LB~  
catch(IOException e){e.printStackTrace ();} `Ns Q&G  
catch(Exception e){e.printStackTrace ();} !&:Cp_  
}  ? 8/r=  
QUaV;6 4  
+~ Hb}0ry  
//读取保存的下载信息(文件指针位置) V^4v`}Wgx  
private void read_nPos()  ;u [:J  
{ #!E`%' s]  
try{ nCQ".G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); RN|Bk  
int nCount = input.readInt(); u})*6l.  
nStartPos = new long[nCount]; mln4Vl(l2M  
nEndPos = new long[nCount]; WrcmC$ff  
for(int i=0;i<nStartPos.length;i++)  + K`.ck  
{ RyU8{-q  
nStartPos = input.readLong(); 5*+DN U@  
nEndPos = input.readLong(); 'J3yJ{  
} !Z |_3  
input.close(); 4_ypFuS^  
} [V qiF~o,  
catch(IOException e){e.printStackTrace ();} yf!7 Q>_G^  
catch(Exception e){e.printStackTrace ();} @$!6u0x  
} O2?yI8|Jn  
EZ:? (|h  
x2a ?ugQ  
private void processErrorCode(int nErrorCode) S=lCzL;j"  
{ wVFa51a)yy  
System.err.println("Error Code : " + nErrorCode); IZm6.F  
} `"PHhCG+z  
&@'%0s9g  
e$_gOwB  
//停止文件下载 +nHr+7}  
public void siteStop() B8?9L8M}  
{ ah f,- ?S  
bStop = true; kZo# Ny  
for(int i=0;i<nStartPos.length;i++) w\ 0vP  
fileSplitterFetch.splitterStop(); H }]Zp  
H C,5j)1  
1h(IrV5g  
} oV;sd5'LG  
} uD?RL~M  
//负责部分文件的抓取 \At~94  
**FileSplitterFetch.java %rJDpB{  
*/ QH4m7M@ni  
package NetFox; #pgD-0_  
.P7q)lj36h  
' `c \Dq  
import java.io.*; f3qR7%X?  
import java.net.*; Er|&4-9  
&bfM`h'  
qo 7<g*kf~  
public class FileSplitterFetch extends Thread { Mpyza%zj  
!/tV}.*  
}No#_{  
String sURL; //File URL R.2i%cU  
long nStartPos; //File Snippet Start Position n0gjcDHQ  
long nEndPos; //File Snippet End Position -?:8s v*X  
int nThreadID; //Thread's ID 1Az&BZU[  
boolean bDownOver = false; //Downing is over qTRP2rH,L&  
boolean bStop = false; //Stop identical h.]^o*DJ  
FileAccessI fileAccessI = null; //File Access interface SmD#hE[  
\)wVO*9*0  
v;5-1  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Q]GS#n  
{ d }fd^x/  
this.sURL = sURL; Sz<:WY/(x  
this.nStartPos = nStart; Gey-8  
this.nEndPos = nEnd; _<jU! R  
nThreadID = id; ,mvFeo;@f  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H)E,([   
} g.Qn,l]X/p  
6Iv};f"Y  
a@&qdp  
public void run() TCzlu#w  
{ :Zkjtr.\  
while(nStartPos < nEndPos && !bStop) UJDI[`2  
{ @ U"Ib  
: UH*Wft1  
m <z?6VC  
try{ ^GrSvl}v'  
URL url = new URL(sURL); K$D+TI)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [h-NX  
httpConnection.setRequestProperty("User-Agent","NetFox"); PPrvVGP   
String sProperty = "bytes="+nStartPos+"-"; \'u+iB g  
httpConnection.setRequestProperty("RANGE",sProperty); [.Md_  
Utility.log(sProperty); bZgo}`o%  
L\"wz scn  
Fje /;p  
InputStream input = httpConnection.getInputStream(); '_Pb\ jK  
//logResponseHead(httpConnection); 4clCZ@\K^  
f% t N2k  
!Sy9v  
byte[] b = new byte[1024]; 3hBYx@jTO  
int nRead; RrrlfFms  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0Bp0ScE|FA  
{ 7Dl^5q.|  
nStartPos += fileAccessI.write(b,0,nRead); ' Kkp!eZQ~  
//if(nThreadID == 1) ,wg(}y'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |0u qW1  
} <_pLmYI  
@XL49D12c  
Gdx %#@/  
Utility.log("Thread " + nThreadID + " is over!"); *L>usLh  
bDownOver = true; z;@<J8I  
//nPos = fileAccessI.write (b,0,nRead); s0vcGh#w  
} ] s 2ec  
catch(Exception e){e.printStackTrace ();} DwFvM0O6\  
} )>b1%x} =  
} 5N6R%2,A  
jt323hHth  
fM:bXR2Y'  
//打印回应的头信息 {Fyw<0 [@  
public void logResponseHead(HttpURLConnection con) s2QgR37s>  
{ \8a014  
for(int i=1;;i++) !=;Evf  
{ ?wmu 0rR  
String header=con.getHeaderFieldKey(i); kn HrMD;  
if(header!=null) XAF]B,h=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %jq R^F:J  
Utility.log(header+" : "+con.getHeaderField(header)); veh=^K%G |  
else ]5`A8-Q@  
break; uQW[2f  
} i>G:*?a  
} rk ,64(  
V_v+i c^  
wod{C!  
public void splitterStop() ~ W8 M3(^  
{ gGA5xkA  
bStop = true; 6rG7/  
} U:MZN[Cc[  
TQ/#  
_uJ6Vy  
} 5HL>2 e[  
a04S&ezj  
{/?{UbU  
/* em^2\*sxpA  
**FileAccess.java WRAv>s9  
*//文件访问(定位,写) >[T6/#M  
package NetFox; }c4F}Cy  
import java.io.*; uF|[MWcy0#  
+U<Ae^V  
o 0b\<}  
public class FileAccessI implements Serializable{ @N> rOA  
2e ~RM2PQ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 HQ4WunH2Y  
RandomAccessFile oSavedFile; rvnm*e,  
long nPos; {"|GV~  
5y0LkuRR:  
T_)+l)  
public FileAccessI() throws IOException r`u 9MJ*  
{ P:X X8&#  
this("",0); j.c4  
} flBJO.2  
#^i+'Z=L  
cx)x="c  
public FileAccessI(String sName,long nPos) throws IOException J[K>)@I/  
{ {=R vFA  
oSavedFile = new RandomAccessFile(sName,"rw"); #LwDs,J:  
this.nPos = nPos; zn*i  
oSavedFile.seek(nPos); l`JKQk   
} g8"{smP/  
*;t_V laZ  
n1+J{EPH  
public synchronized int write(byte[] b,int nStart,int nLen) )5;|mV  
{ _J3\e%ys  
int n = -1; W`wT0kP?*]  
try{ `wLmGv+V  
oSavedFile.write(b,nStart,nLen); 2V+[:>F  
n = nLen; g@>y`AFnr  
} CFY4PuI"!  
catch(IOException e) a[lx&CHgI  
{ 0b,{4DOD  
e.printStackTrace (); {`L,F  
} 9B3}LVg\  
*(*XNd||  
.8|5;!`WB  
return n; '+S!>Lqb  
} O,I7M?dRf  
hM(Hq4ed,  
Qcs0w(  
} etP`q:6^c  
= &U7:u  
N9f;X{  
/* Ahg6>7+R.  
**SiteInfoBean.java kRzqgVr%  
*/ P'Jb')m  
package NetFox; G&0JK ,Y  
< *{(>  
-f(< 2i  
public class SiteInfoBean { gBd~:ZUa  
_NbhWv  
dFpP_U  
private String sSiteURL; //Site's URL L w/ZKXDU2  
private String sFilePath; //Saved File's Path MS%h`Ypo  
private String sFileName; //Saved File's Name 8ax3"G  
private int nSplitter; //Count of Splited Downloading File 'DH_ihZ  
nZS*"O#L  
g[xn0 rG  
public SiteInfoBean() y {Mh ?H  
{//nSplitter的缺省值为5 $4TawFf"nc  
//default value of nSplitter is 5 2 BwpxV8  
this("","","",5); v|>'m#Ln2  
} jZ69sDhE  
qjvIp-  
B;L^!sLP  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2) A$bx  
{ H*dQT y,  
sSiteURL= sURL; }KrZ6cG9#  
sFilePath = sPath; kI$X~s$r  
sFileName = sName; zB{be_Tw  
this.nSplitter = nSpiltter; JvLa@E)  
:cTwp K  
Dr"F5Wbg  
} AyZBH &}RZ  
~48mCD  
TqMy">>  
public String getSSiteURL() 4dvuw{NZ  
{ V6 ,59  
return sSiteURL; )'?@raB!  
} .J|" bs9  
^`!EpO>k9  
o"A%dC_  
public void setSSiteURL(String value) nF| m*_DW  
{ <0)@Ikhx  
sSiteURL = value; uI[lrMQYa  
} IqONDdep9  
P!2[#TL0  
,t>/_pI+=  
public String getSFilePath() $yg}HS7HC  
{ !7[Rhk7bW  
return sFilePath; dCMWv~>  
} ~4~>; e  
kv3jbSKCT  
axi%5:I  
public void setSFilePath(String value) V?Zvu9b&  
{ Eq/%k $6#1  
sFilePath = value; G;pxB,4s5  
} $X;fz)u  
X<"W@  
%7rWebd-  
public String getSFileName() t%<d}QuHW  
{ zc-.W2"Hu  
return sFileName; J;BG/VI1  
} e c`3Qw  
G@QZmuj&KH  
<)(STo  
public void setSFileName(String value) xlaBOKa%  
{ wXsA-H/`  
sFileName = value; QFf lx  
} dPRGL hWF  
e[8p/hId  
6*2z^P9FRj  
public int getNSplitter() cB7=4:U  
{ G P/3r[MH  
return nSplitter; 7nHlDPps)  
} "VcG3.  
5 lC"10  
GVp2| \-L  
public void setNSplitter(int nCount) 8V3SZ17  
{ O<h`[1eUjS  
nSplitter = nCount; b9([)8  
} S\jN:o#b  
} RyxIJJui  
rm4j8~Ef  
Y&5h_3K;<  
/* 8a1G0HRQ  
**Utility.java a8%/Xwr~  
*/ '?k*wEu  
package NetFox;  B9^@]  
Jj'~\j  
*(x`cf;k  
public class Utility { l+Tw#2s$  
%zB `Sd<  
w]\O3'0Js  
public Utility() |L7 `7!Z  
{ (byFr9z  
'5eW"HGU]`  
G?d28p',.  
} z6R<*$4  
*Ta*0Fr=9|  
//线程睡眠 0BIH.ZV#  
public static void sleep(int nSecond) kf$0}T`  
{ @$;"nVZ4v  
try{ M(S:&GOU  
Thread.sleep(nSecond); ]#[ R^t  
} 6?ylSQ]1  
catch(Exception e) OY6l t.t  
{ d7tH~9GX8  
e.printStackTrace (); cX553&  
} b07 MTDFH7  
} Y] nY.5irL  
e2%Y8ZJG.  
//日志 Zcv1%hI  
public static void log(String sMsg) e?G] fz  
{ ?+b )=Z  
System.err.println(sMsg); g(MeCoCc  
} 6P!M+PO  
mg*[,_3q33  
z.pP~he  
public static void log(int sMsg) W04-D  
{ bY;ah;<  
System.err.println(sMsg); oO>mGl36H  
} `hL16S  
} 5>JrTO 5  
dH zo_VV  
>t O(S  
/* X'WbS  
**TestMethod.java 'zZN]P  
*/ q!9SANTx  
package NetFox; R y0n_J:7  
zrG&p Z  
_Y*]'?g`  
public class TestMethod { Q5/".x^@  
5B@+$D[0?3  
4?,N;Q  
public TestMethod() +=^10D  
{ ///xx/weblogic60b2_win.exe a4L8MgF&$-  
try{ $v+Q~\'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N'!a{rF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~(%nnG6x  
SiteFileFetch fileFetch = new SiteFileFetch(bean); S!k cC-7  
fileFetch.start(); o6ec\v!l-  
} d?*=<w!A  
catch(Exception e){e.printStackTrace ();} \:\rkc9LI  
sUcx;<|BC  
-D0kp~AO4N  
} *<zfe.  
Sim\+SL{#  
}^^X-_XT  
public static void main(String[] args) 0S;H`w_S  
{ INE8@}e  
new TestMethod(); -Yy,L%E]F:  
} ;+`t[ go  
} {d(@o!;Fi  
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