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http断点续传简单实现(java)

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/* p#wQW[6  
**SiteFileFetch.java D>|m8-@]  
*/ l E=(6Q  
package NetFox; yl/-!  
import java.io.*; zRd^Uks  
import java.net.*; o|YY,G=C  
(/UW}$] h  
Hm!ffqO_  
public class SiteFileFetch extends Thread { :hr% 6K7  
hCVe05  
%4|*  
SiteInfoBean siteInfoBean = null; //文件信息Bean gHpA@jdC*  
long[] nStartPos; //开始位置 0}C> e`<'  
long[] nEndPos; //结束位置 [nZf4KN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  S<#>g s4  
long nFileLength; //文件长度 {4J:t_<nKO  
boolean bFirst = true; //是否第一次取文件 zP$0B!9  
boolean bStop = false; //停止标志 IL;JdIa  
File tmpFile; //文件下载的临时信息 kU{+@MA;  
DataOutputStream output; //输出到文件的输出流 @E;'Ffo  
XP'<\  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) gBp,p\ Xc  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q>Voa&tYn  
{ ^aYlu0Wm  
siteInfoBean = bean; ?~X*\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); vikA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;rXkU9  
if(tmpFile.exists ()) }K':tX?  
{ Q#w mS&$f  
bFirst = false; &YC Z L  
read_nPos(); h_#x@p  
} > Dy<@e  
else ix4O-o{  
{ <qJI]P  
nStartPos = new long[bean.getNSplitter()]; FcVQ_6  
nEndPos = new long[bean.getNSplitter()]; P'%#B&LZo  
} dO]N&'P7  
{w:*t)@j  
U4)x"s[CP  
<LL+\kfTZO  
} Sk7l&B  
p}H:t24Cr5  
$WmB__  
public void run() t|-TG\Q X  
{ t6u>_Sh e  
//获得文件长度 \OPJ*/U  
//分割文件 0<tce  
//实例FileSplitterFetch ^{Wx\+*!  
//启动FileSplitterFetch线程 hWc`4xdl  
//等待子线程返回 zwJB.4@  
try{ } DQ<YF+  
if(bFirst) ?+Gc. lU  
{ 1<|\df.  
nFileLength = getFileSize(); j11FEE<W  
if(nFileLength == -1) mV!Ia-k  
{ )S?.YCv?  
System.err.println("File Length is not known!"); 6d~[j <@2  
} N{+6V`\  
else if(nFileLength == -2) TQ`s&8"P  
{ UU\wP(f  
System.err.println("File is not access!"); 4`E[ WE:Q  
} t&|M@Ouet  
else >-8r|};+  
{ XBx&&  
for(int i=0;i<nStartPos.length;i++)  -c%#Hd  
{ <[.{aj]QV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P:D@ 5  
} qZQB"Q.*  
for(int i=0;i<nEndPos.length-1;i++) *^[m?3"W  
{ @yV.Yx"p_  
nEndPos = nStartPos[i+1]; Yr!@pHy  
} )R %>g-dw  
nEndPos[nEndPos.length-1] = nFileLength; B ]*v{?<W  
} T{ WJf-pI  
} ZkWX4?&OMt  
JG^fu*K  
$-^ ;Jl  
//启动子线程 LV}Z[\?   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VT ikLuH  
for(int i=0;i<nStartPos.length;i++) ;]gj:6M  
{ ycD.X"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9 +1}8"~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), e^!>W %.7Z  
nStartPos,nEndPos,i); uwI$t[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s!73To}>  
fileSplitterFetch.start(); I{nrOb1G(  
} q,;8Ka )  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ! 2=m |,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); GN1Q\8)o  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %Z~0vwY  
nEndPos = " + nFileLength); >o/+z18x  
// fileSplitterFetch[nPos.length-1].start(); B`<a~V  
`@<>"ff#F  
y@XE! L  
//等待子线程结束 9U]3B)h%m  
//int count = 0; TmviYP gb  
//是否结束while循环 (V(8E%<c  
boolean breakWhile = false; G^1 5V'*  
G/ sRi wL  
ol3].0Vc]  
while(!bStop) =w!>/#U  
{ !)r1zSY"g  
write_nPos(); pNFVa<D  
Utility.sleep(500); uKA-<nM._c  
breakWhile = true; F ?N+ __o  
_ASyGmO{  
.n\j<Kq  
for(int i=0;i<nStartPos.length;i++) 7&`Yl[G  
{ c`Q#4e]%_  
if(!fileSplitterFetch.bDownOver) %2@O,uCo@  
{ ?3#L?Cq  
breakWhile = false; $G<!+^T  
break; }Y~<|vZ  
} ,DL%oQR  
} qtR/K=^i  
if(breakWhile) )U|0vr8:  
break; ~o8  
R4_BP5+  
d DrzO*a\  
//count++; W?H-Ng3E  
//if(count>4) f7_V ]  
// siteStop(); |S6L[Uo  
} Au10]b  
n@=D,'cn  
XpH d"(*  
System.err.println("文件下载结束!"); ]mR!-Fqj  
} mI> =S  
catch(Exception e){e.printStackTrace ();} 'w"hG$".  
} Xk>YiV",?  
> I>=/i^  
)z\ 73|w  
//获得文件长度 he! Uq%e  
public long getFileSize() 'ZFbyt Q2  
{ c BcZ@e;  
int nFileLength = -1; @ JfQ}`  
try{ 'O^<i`8U]  
URL url = new URL(siteInfoBean.getSSiteURL()); b3.}m[]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?Gnx!3Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); i'YM9*yN  
+/>XOY|Ie  
P>nz8NRq  
int responseCode=httpConnection.getResponseCode(); !sVW0JSh  
if(responseCode>=400) nPR*mbW  
{ itmFZZh  
processErrorCode(responseCode); wiP )"g.t  
return -2; //-2 represent access is error h+DK .$  
} c#zx" ,K  
4+B&/}FDLo  
tk\)]kj  
String sHeader; ;9;jUQ]MyG  
PfN[)s4F{R  
gP2<L5&Z,  
for(int i=1;;i++) O0_kLH$.  
{ /l` "@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); TCI)L}L|  
//Utility.log(in.readLine()); /?%1;s:'  
sHeader=httpConnection.getHeaderFieldKey(i); *v#Z/RrrA  
if(sHeader!=null) {d '>J<Da  
{ &BxZ}JH=k  
if(sHeader.equals("Content-Length")) je;|zfe]  
{ \R[f< K%  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,1 ^IFBJ  
break; K3^2;j1F Q  
} *&BS[0;  
} X:JU#sI  
else rVM?[_'O  
break; *J3Z.fq%:i  
} 'FM_5`&  
} 2l}H=DZV  
catch(IOException e){e.printStackTrace ();} Oj1B @QE  
catch(Exception e){e.printStackTrace ();} r7+Ytr  
G%MdZg&i  
MlV3qM@  
Utility.log(nFileLength); B=)tq.Q7  
R4%}IT^%P  
)mu[ye"p  
return nFileLength; ('6sW/F*ab  
} H;N6X y*~  
=X3Rk)2r  
|"+UCAU  
//保存下载信息(文件指针位置) 2O(= 2X  
private void write_nPos() z9 $1jC  
{ b *Ca*!  
try{ |xFSGrC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]D<3y IGS  
output.writeInt(nStartPos.length); J'C%  
for(int i=0;i<nStartPos.length;i++) }k0B   
{ bScW<DZJ-  
// output.writeLong(nPos); /s Bs eI  
output.writeLong(fileSplitterFetch.nStartPos); XP(fWRT1  
output.writeLong(fileSplitterFetch.nEndPos); \:jJ{bl^A  
} bL2b^UB~%  
output.close(); -Mzm~@_s]  
} ,In}be$:  
catch(IOException e){e.printStackTrace ();} <O3,b:vw  
catch(Exception e){e.printStackTrace ();} WesEZ\V  
} hQ}y(2A.XI  
TG6E^3a P  
^wD@)Dz  
//读取保存的下载信息(文件指针位置) RG6U~o1  
private void read_nPos() M.K%;j`  
{ ;Dp<|n  
try{ r*g<A2g%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,&LGAa  
int nCount = input.readInt(); jJ3dZ<#  
nStartPos = new long[nCount]; Q\ pI\]p:  
nEndPos = new long[nCount]; Z$y~:bz  
for(int i=0;i<nStartPos.length;i++) $O9,Gvnxx  
{ aucG|}B  
nStartPos = input.readLong(); % U|4%P  
nEndPos = input.readLong(); >JHQA1mX  
} )\+1*R|H}  
input.close(); y Dw#V`Y^M  
} ;:aCZ8e  
catch(IOException e){e.printStackTrace ();} #@:GLmD%  
catch(Exception e){e.printStackTrace ();} j4+kL4M@H  
} (%)<jg1  
<P_B|Y4N/  
LLPbZ9q  
private void processErrorCode(int nErrorCode) ?sc lOOh  
{ v5 I}a7  
System.err.println("Error Code : " + nErrorCode); P( 1Z  
} ;v m$F251  
[&+5E1%L  
S8Yti  
//停止文件下载 vt(cC) )  
public void siteStop() EttQ<z_T  
{ eT@, QA(3  
bStop = true; k? !'OHmBL  
for(int i=0;i<nStartPos.length;i++) )KKmV6>b  
fileSplitterFetch.splitterStop(); B`?5G\7L  
v4VP7h6uD)  
Fjw+D1q.  
} Y(R .e7]  
} lj 2OOU{  
//负责部分文件的抓取  K2D, *w  
**FileSplitterFetch.java =6xxZy[  
*/ wY*tq{7  
package NetFox; f5,!,]XO  
sh;>6xB  
dPmNX-'7  
import java.io.*; %<h+_(\h  
import java.net.*; wqAj=1M\  
7i88iT  
Q6hWHfS  
public class FileSplitterFetch extends Thread { ;` ! j~  
i| CAN,'  
wqA7_ -  
String sURL; //File URL J'@`+veE  
long nStartPos; //File Snippet Start Position ,rWej;CzN  
long nEndPos; //File Snippet End Position ,XYtoZa  
int nThreadID; //Thread's ID 2!";?E  
boolean bDownOver = false; //Downing is over "U*6?]f  
boolean bStop = false; //Stop identical lH"4"r  
FileAccessI fileAccessI = null; //File Access interface #_'| TT>p#  
'<Jqp7$dL  
aUbmEHFTV  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *V?p&/>MT  
{ 1Ts$kdO  
this.sURL = sURL; \kG;T=H  
this.nStartPos = nStart; ?K= X[  
this.nEndPos = nEnd; BL H~`N3U  
nThreadID = id; wD5fm5r=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |WsB0R  
} tQ Ia6c4|  
yc.9CTxx  
ab^>_xD<  
public void run() $m;DwlM  
{ ~ }?*v}  
while(nStartPos < nEndPos && !bStop) X^)v ZL?  
{ `-[|@QNFz  
YxWA] yL  
|%12Vr]J  
try{ 0tEe $9eK@  
URL url = new URL(sURL); XG01g3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @Q%<~b[y  
httpConnection.setRequestProperty("User-Agent","NetFox"); ( !0fmL  
String sProperty = "bytes="+nStartPos+"-"; tl^![Z  
httpConnection.setRequestProperty("RANGE",sProperty); y28 e=i  
Utility.log(sProperty); Rp_)LA  
!+T29QYK8  
~'#,*kA:6  
InputStream input = httpConnection.getInputStream(); =k:yBswi  
//logResponseHead(httpConnection); lFbf9s:$B  
Jq_AR!} %  
FwqaWEk  
byte[] b = new byte[1024]; <L+y 6B  
int nRead; evGUl~</~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >6 A8+=  
{ 48RSuH  
nStartPos += fileAccessI.write(b,0,nRead); zaG1  
//if(nThreadID == 1) Q8^g WBc  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C!}t6  
} 6Ej.X)~'K  
< m/@_"  
KYR64[1  
Utility.log("Thread " + nThreadID + " is over!"); :Hq#co  
bDownOver = true; `w EAU7m:  
//nPos = fileAccessI.write (b,0,nRead); Z Z9D6+R  
} 9;R'Xo=y  
catch(Exception e){e.printStackTrace ();} `} S; _g!  
} H,0Io  
} Xsd+5="{N  
u:M)JG  
XxLauJP K  
//打印回应的头信息 Y|~+bKa  
public void logResponseHead(HttpURLConnection con) D"8?4+  
{ kn&>4/')  
for(int i=1;;i++) T1i}D"H %  
{ +{au$v}  
String header=con.getHeaderFieldKey(i); I8Q!`K J  
if(header!=null) o e,yCdPs  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); '|@?R|i0  
Utility.log(header+" : "+con.getHeaderField(header)); $$e"[g  
else lky5%H  
break; M6XpauR-  
} \`Ow)t:  
} T':} p2}w+  
!U4<4<+  
jP}Ix8vc=  
public void splitterStop() DE!c+s_g4  
{ }fh<LCwTi  
bStop = true; q6EZ?bo{  
} THY=8&x)  
s5J?,xu  
GGez!?E%  
} 4x|\xg( l  
4KB>O)YNg'  
W[t0hbV w  
/* 1h#e-Oyff  
**FileAccess.java Sc9}W U  
*//文件访问(定位,写) bPVQ-  
package NetFox; *u]aWx  
import java.io.*; >,a$)z  
.> 5[;  
GBYwS{4  
public class FileAccessI implements Serializable{ ):7mK03J  
'q\[aKEX=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vJ{aBx`VS  
RandomAccessFile oSavedFile; h?P- :E  
long nPos; GUC.t7!  
^T*'B-`C7X  
9wdl1QS  
public FileAccessI() throws IOException |vtj0 ,[  
{ wyB  
this("",0); $[V-M\q  
} 2Z+:^5  
*9tRh Rc  
*;[g Ga~  
public FileAccessI(String sName,long nPos) throws IOException (O"-6`w[  
{ ^NXxMC( e+  
oSavedFile = new RandomAccessFile(sName,"rw");  6h?)x  
this.nPos = nPos; +;bP.[Z  
oSavedFile.seek(nPos); {<Y\flj{@m  
} )4^Sz&\  
$7*@TMX  
R?HuDxHk  
public synchronized int write(byte[] b,int nStart,int nLen) eXi}-~o  
{ 4(&sw<k  
int n = -1; "2Q*-  
try{ p|Qn?^C:  
oSavedFile.write(b,nStart,nLen); ?H!QV;ku  
n = nLen; e[Jh7r>'  
} ..Bf-)w  
catch(IOException e) _*++xF1  
{ th%T(D5n  
e.printStackTrace (); Wo{4*~f  
} [Gc9 3PA7q  
ZoR6f\2M  
{ t@7r  
return n; 6[Wv g  
} DLO2$d  
Ie(M9QMp  
+}iuTqu5  
} 6"yIk4u:  
v]y=+* A  
y wmC>`0p  
/* [:8+ +#KD  
**SiteInfoBean.java ),XDY_9K  
*/ 7X<#  
package NetFox; Y'yGhpT~  
;%Kh~  
;]>a7o  
public class SiteInfoBean { 7M<co,"  
C(n_*8{  
cUr5x8<W).  
private String sSiteURL; //Site's URL ZMGC@4^F  
private String sFilePath; //Saved File's Path gWfMUl  
private String sFileName; //Saved File's Name pkc*toW  
private int nSplitter; //Count of Splited Downloading File g`dAj4B  
W1ql[DqE{  
bMGXx>x  
public SiteInfoBean() yH0vESgv  
{//nSplitter的缺省值为5 S]?I7_  
//default value of nSplitter is 5 gwDVWhq  
this("","","",5); jD ?*sd  
} dH)\zCt  
IHv>V9yiG  
t:YMF$Z  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) KM/c^ a4V  
{ OlM3G^1e1  
sSiteURL= sURL; lJt?0;gn  
sFilePath = sPath; WmuYHEU  
sFileName = sName; 4VhKV JX  
this.nSplitter = nSpiltter; QBjvbWoIG(  
(Q"~bP{F  
>cH}sNHy  
} vf-8DB  
]Xg7XY  
7n7UL0Oc1  
public String getSSiteURL() Z6#(83G4  
{ 4A)_D{(SH  
return sSiteURL; Q+*@!s  
} KebC$g@W  
"Ug+# ;}p$  
7MIrrhk  
public void setSSiteURL(String value) +iw4>0pi  
{ o\X|\nUk  
sSiteURL = value; x{S2   
} ,zh_-2^X  
T:g%b @  
hbm #H7Y  
public String getSFilePath() d(C5i8d  
{ e6Kyu*  
return sFilePath; QObHW[:F  
} (3&P8ZGNR  
x5b .^75p$  
))I[@D1b  
public void setSFilePath(String value) ak zKX}  
{ !:a^f2^=  
sFilePath = value; m2[J5n?zLL  
} JvYs6u  
AE=E"l1]  
@[bFlqs E  
public String getSFileName() |}Z2YDwO/  
{ e?:1wU  
return sFileName; WQsu}_g5y  
} .f`KP!p.  
T>w;M?`9K  
8Yf=)  
public void setSFileName(String value) cC9haxW  
{ DK1{Z;Z  
sFileName = value; %rO)w?  
} E+J+fi  
(?ZS 9&y}  
Tj6kCB  
public int getNSplitter() p5J!j I=  
{ 95Q^7oI  
return nSplitter; ,3Nna:~f  
} ?;ZnD(4?  
$`<-;kI  
!*o{xq   
public void setNSplitter(int nCount) { }P~nP  
{ w`[`:H_z  
nSplitter = nCount; 5 Q,j+  
} 9>;CvR  
} &t}6sD9o  
&}d5'IRT  
f<>CSjQ4c  
/* fzUG1|$e  
**Utility.java Nb)Mh  
*/ ( ; _AP.  
package NetFox; ie7P^:T|+  
Nt687  
dg&GMo  
public class Utility { S2EV[K8#  
o0TB>DX$`  
0@RVM|  
public Utility() L$ZsNs+  
{ w@H@[x  
iyr<qtwK  
U "v=XK)!  
} M|7][! <G!  
U5[r&Y D  
//线程睡眠 |{La@X  
public static void sleep(int nSecond) `t+;[G>ZE  
{ FBa- gm<9  
try{ L$^)QxH7  
Thread.sleep(nSecond); >J{e_C2ZS  
} zICrp  
catch(Exception e) zb.sh  
{ S 9;FD3  
e.printStackTrace (); Bnw^W _  
} )lP(is FP  
} Z<'iT%6+r  
H=9{|%iS  
//日志 l@`n4U.Gwl  
public static void log(String sMsg) {dlG3P='`f  
{ q><wzCnRu~  
System.err.println(sMsg); ;A0ZcgF  
} (O/W`qo  
oSl}A,aQ(  
[d=BN ,?  
public static void log(int sMsg) |}@teN^J*U  
{ qNUd "%S  
System.err.println(sMsg); VH] <o0  
} O6ltGtF  
} +pe\9F  
? 3oUkGfn  
J)sOne  
/* 79B+8= K  
**TestMethod.java .e\PCf9v  
*/ lDVgW}o@  
package NetFox; ^G "Qp8 "  
 p4P"U  
MR zY<MD  
public class TestMethod { yO@@-)$[y  
&D&U!3~(  
HcpAp]L)  
public TestMethod() $5@[l5cJU;  
{ ///xx/weblogic60b2_win.exe HC"yC;_  
try{ $|VdGRZ1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); qR kPl!5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); K{XE|g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Mtn{63cK  
fileFetch.start(); [@NW  
} Fe2t[y:8h  
catch(Exception e){e.printStackTrace ();} ;8cTy8  
ek d[|g  
f||S?ns_  
} ~|ha9 1  
wdIJ?\/763  
rj/nn)vv;  
public static void main(String[] args) 31N5dIi,  
{ fn8|@)J  
new TestMethod(); Q)5V3Q]@^  
} 'fZ\uMdTx  
} hJ?PV@xy  
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