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http断点续传简单实现(java)

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/* [ x|{VJ(h  
**SiteFileFetch.java rx;zd?  
*/ j-etEWOTr  
package NetFox; GEi^3UD  
import java.io.*; mdHC{sp  
import java.net.*; aMjCqu05  
jl4rEzVu  
*CXVA&?  
public class SiteFileFetch extends Thread { \(ZOt.3!J  
FKB)o7  
>pA9'KWs]  
SiteInfoBean siteInfoBean = null; //文件信息Bean  /=7[Q  
long[] nStartPos; //开始位置 ^zaN?0%S33  
long[] nEndPos; //结束位置 "A9 c]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 cb~m==G  
long nFileLength; //文件长度 \>-%OcYlM  
boolean bFirst = true; //是否第一次取文件 RpY#_\^hI  
boolean bStop = false; //停止标志 _u`W$EG L  
File tmpFile; //文件下载的临时信息 wD&b[i  
DataOutputStream output; //输出到文件的输出流 J&6]3x  
Z?-l-s K  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) T/C1x9=?  
public SiteFileFetch(SiteInfoBean bean) throws IOException W1J7$   
{ (wIpq<%  
siteInfoBean = bean; ouUU(jj02  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \6${Na' \  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {%b-~& F9  
if(tmpFile.exists ()) NASRr  
{ JEes'H}Y  
bFirst = false; z '%Vy  
read_nPos(); ?5 d3k%  
} XX(;,[(_  
else ?Yp: h  
{ 1cdM^k  
nStartPos = new long[bean.getNSplitter()]; C,D~2G  
nEndPos = new long[bean.getNSplitter()]; etH%E aF[  
} dGzZ_Vf  
*l^%7W rk  
4<&`\<jZ  
;=6~,k)  
} 3J}bI {3  
up7]Yy;o=  
jM3{A;U2  
public void run() <&rvv4*H  
{ bmO[9 )G  
//获得文件长度 RtR]9^:~  
//分割文件 IPnbR)[%  
//实例FileSplitterFetch 6]^}GyM!  
//启动FileSplitterFetch线程 l8hOryB&  
//等待子线程返回 o3l_&?^  
try{ Xu:S h<:R  
if(bFirst) MLcc   
{ 3l 0>  
nFileLength = getFileSize(); m>6,{g)  
if(nFileLength == -1) pemb2HQ'4j  
{ x AD:Z "  
System.err.println("File Length is not known!"); nV%1/e"5  
} v7/qJ9l  
else if(nFileLength == -2) e? fFh,a  
{ ~V"D|U;i +  
System.err.println("File is not access!"); yg gQ4y6  
} LEkO#F(  
else :WT O*M  
{ \qqt/  
for(int i=0;i<nStartPos.length;i++) tq^H)  
{ T?c:z?j_9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >_]j{}~\k  
} |}\et ecB  
for(int i=0;i<nEndPos.length-1;i++) ,!3G  
{ >T4.mB7+>  
nEndPos = nStartPos[i+1]; P/?`  
} "el}@  
nEndPos[nEndPos.length-1] = nFileLength; Q': }'CI  
} Xb=9~7&,$  
} R1FBH:Iu  
_{6QvD3kg.  
Cv|ya$}a  
//启动子线程 cSBYC_LU  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nmVL%66K  
for(int i=0;i<nStartPos.length;i++) W@1Nit-R  
{ _d&FB~=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5TVDt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C-$S]6  
nStartPos,nEndPos,i); hof:+aW  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ajW[}/)  
fileSplitterFetch.start(); _.OajE\T  
} c?CjJ}-7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9Ay*'   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5~CHj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0I4RZ.2*Y  
nEndPos = " + nFileLength); a="Z]JGk  
// fileSplitterFetch[nPos.length-1].start(); V7!x-E/  
C9U~lcIS  
o@r+Y  
//等待子线程结束 e qQAst#~  
//int count = 0; m#mM2Guxe  
//是否结束while循环 g&H6~ +\  
boolean breakWhile = false; `6b!W0$ -  
T"XP`gk  
G_g~-[O  
while(!bStop) i!<,8e=  
{ auqM>yx  
write_nPos(); HKCMKHR  
Utility.sleep(500); =)(o(bfSKr  
breakWhile = true; i3*S`/]p  
" ;cWK29\f  
YsXP$y]g-  
for(int i=0;i<nStartPos.length;i++) z{cIG8z  
{ ]n0kO&  
if(!fileSplitterFetch.bDownOver) GmB7@-[QA%  
{ b,8W |  
breakWhile = false; a 1Qg&s<  
break; Tz1St{s\  
} ^ S'}RZ*>  
} ;GO>#yg4Eh  
if(breakWhile) ,YJ\ $?  
break; Q_xE:#!;  
yw2^kk93|  
C+$dm)M/q  
//count++; iK1<4)  
//if(count>4) >n)N=Zyu  
// siteStop(); V4}9f5FR  
} HjV3PFg  
-4o6 OkK<  
L{;q^  
System.err.println("文件下载结束!"); qCn(~:  
} <XX\4[wb  
catch(Exception e){e.printStackTrace ();} Sb+pB58&N  
} l)fF)\|;=  
Q i#%&Jz>f  
Z16G  
//获得文件长度 R 28v5  
public long getFileSize() s!``OyI/Z  
{ ZJ@M}-4O1  
int nFileLength = -1; #[C |%uq  
try{ J (Yfup  
URL url = new URL(siteInfoBean.getSSiteURL()); 0ejx; Mum  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iV[g.sP-  
httpConnection.setRequestProperty("User-Agent","NetFox"); s (J,TS#I]  
!9DqW&8  
' D+h_*H  
int responseCode=httpConnection.getResponseCode(); ~S15tZ $  
if(responseCode>=400) .HF+JHIUu  
{ %p)6m 2Sb  
processErrorCode(responseCode); |j$&W;yC  
return -2; //-2 represent access is error @;M( oFS9  
} 3Ln~"HwP  
g= k}6"F~  
i2/:' i  
String sHeader; .{LFc|Z[  
yv^j~  
@dV'v{:,  
for(int i=1;;i++) G eN('0  
{ qi_[@da f?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wP- pFc  
//Utility.log(in.readLine()); f@T/^|`mh  
sHeader=httpConnection.getHeaderFieldKey(i); ~cVFCM  
if(sHeader!=null) deHhl(U;  
{ 1+v&SU  
if(sHeader.equals("Content-Length")) C 2Fklp6  
{ Z!60n{T79c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V|ax(tHv  
break; 2cr~/,YY  
}  8Br*  
}  ;?1H&  
else 2Otd  
break; W)ihk\E  
} I.A7H'j  
} "]Wrir?l  
catch(IOException e){e.printStackTrace ();} +^YXqOXU  
catch(Exception e){e.printStackTrace ();} E!&A[TlX\  
-bu.Ar-#;h  
bv$_t)Xh  
Utility.log(nFileLength); @T  
:2{6Pa(eg  
kG/:fP  
return nFileLength; ifl`QZp_  
} \dTX%<5D  
lcHw Kd  
rlmzbIu I9  
//保存下载信息(文件指针位置) +',[q  
private void write_nPos() E8zga )  
{ /UTeaM!?"  
try{ N}b/; Y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); kB {  
output.writeInt(nStartPos.length); o8.KakrPP  
for(int i=0;i<nStartPos.length;i++) 0m $f9b|Q?  
{ ^A dHP!I  
// output.writeLong(nPos); ?*|AcMw5  
output.writeLong(fileSplitterFetch.nStartPos); im|( 4 f  
output.writeLong(fileSplitterFetch.nEndPos); trcG^uV  
} Q{T6t;eH  
output.close(); 7T9m@  
} >Lx,<sE  
catch(IOException e){e.printStackTrace ();} q  9lz  
catch(Exception e){e.printStackTrace ();} ]l7) F-v  
} kg?[   
=<R")D]4z  
'd4I/  
//读取保存的下载信息(文件指针位置) S.1\e"MfI  
private void read_nPos() [Hw  
{ rXc-V},az8  
try{ L|.q19b*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5wYYYo=  
int nCount = input.readInt(); =/Pmi_  
nStartPos = new long[nCount];  \B) a57  
nEndPos = new long[nCount]; a|rN %hA4  
for(int i=0;i<nStartPos.length;i++) ~=91Kxf  
{ 5[}3j1  
nStartPos = input.readLong(); Osncl5PD)  
nEndPos = input.readLong(); 9W88_rE'e}  
} ".A+'pJ  
input.close(); NC'+-P'y  
} 'NHtCs=F   
catch(IOException e){e.printStackTrace ();} 1$T;u~vg  
catch(Exception e){e.printStackTrace ();} "S)2<tV  
} <qjNX-|  
@q:v?AO  
/8(c^  
private void processErrorCode(int nErrorCode) ~XGBE  
{ $Wt0e 4YSu  
System.err.println("Error Code : " + nErrorCode); /(Mi2$@v1  
} f.8Jp<S2K  
mW~t/$Y$  
|^9+c2   
//停止文件下载 5Z"IM8?  
public void siteStop() uvR9BL2=  
{ JLo'=(  
bStop = true; s+IU%y/9$a  
for(int i=0;i<nStartPos.length;i++) vFKX@wV S  
fileSplitterFetch.splitterStop(); gv)F`uRWA  
4Gz5Ju  
&AM<H}>  
} 7R9.g6j  
} vU,AOK[l{  
//负责部分文件的抓取 kHLpa/A  
**FileSplitterFetch.java vM )2F  
*/ p|fSPSz  
package NetFox; !lxs1!:  
QcQQQM  
C><]o  
import java.io.*; .,Q j3  
import java.net.*; eS)2#=  
uG<VQ2LM  
/]7FX"  
public class FileSplitterFetch extends Thread { CR8a)X4j#  
{6H%4n  
GP=i6I6C  
String sURL; //File URL |m{Q_zAB  
long nStartPos; //File Snippet Start Position + / s2;G  
long nEndPos; //File Snippet End Position qYpuo D   
int nThreadID; //Thread's ID [MLJs-*   
boolean bDownOver = false; //Downing is over >d#oJ?goX  
boolean bStop = false; //Stop identical h1O^~"x  
FileAccessI fileAccessI = null; //File Access interface Z{-x}${  
V)x(\ls]SX  
qkQ _#  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException E.~;  
{ !;Hi9,<#7g  
this.sURL = sURL; DXX(qk)6  
this.nStartPos = nStart; UrAg*v!Qy  
this.nEndPos = nEnd; V.<$c1#=$  
nThreadID = id; >JdA,i}1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 X^204K%:  
} C-25\  
"mT95x\NA\  
"s[Y$!#  
public void run() ;/tZsE{  
{ ^Ej4^d  
while(nStartPos < nEndPos && !bStop) ?naPti1GX  
{ p#-ov-znp  
lIR0jgP@z  
Hgu:*iYA  
try{ nT7{`aaQl  
URL url = new URL(sURL); [HEqMBX=;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n0nf;E  
httpConnection.setRequestProperty("User-Agent","NetFox"); e| AA7  
String sProperty = "bytes="+nStartPos+"-"; 4a'O#;h o  
httpConnection.setRequestProperty("RANGE",sProperty); DGfhS`X  
Utility.log(sProperty); ?Q$LIoR  
/48W]a}JS  
2 uuI_9 "^  
InputStream input = httpConnection.getInputStream(); >y P`8Oq[  
//logResponseHead(httpConnection); 2kv%k3 Q{  
D+$k  
kk`BwRh)d;  
byte[] b = new byte[1024]; -KzU''  
int nRead; /cmnX'z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G`!ff  
{ _W@SCV)yH  
nStartPos += fileAccessI.write(b,0,nRead); dU!`aPL?  
//if(nThreadID == 1) 3,`.$   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NF?FEUoxz  
} iQ[0d.(A  
sU7>q}!  
>;E[XG^  
Utility.log("Thread " + nThreadID + " is over!"); qg7] YT&  
bDownOver = true; sOyWsXd+R'  
//nPos = fileAccessI.write (b,0,nRead); iz|mJUx  
} w1zI"G~4/Q  
catch(Exception e){e.printStackTrace ();} |. bp  
} TmN}TMhZ  
} IKJ~sw~AQ  
O5"o/Y~m  
 eiLtZQ  
//打印回应的头信息 WA);Z=  
public void logResponseHead(HttpURLConnection con) P1P P#>E-2  
{ &&1q@m,cP  
for(int i=1;;i++) Sr7+DCr  
{ E\M{/.4 4  
String header=con.getHeaderFieldKey(i); DNgQ.lV  
if(header!=null) wp/u*g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4fDo}~  
Utility.log(header+" : "+con.getHeaderField(header)); ' pE %'8R  
else |pIA9/~Z  
break;  L_+0[A  
} Dl862$_Q  
} nMU#g])y)  
WY@x2bBi  
f;/t7=>d  
public void splitterStop() * *?mZtF  
{ (wJtEoB9^  
bStop = true; cz_4cMgxu  
} lYd#pNN  
V/5hEoDt  
h6*=Fn7C  
} T[$Sbz`  
Z$R2Z$f  
{HqwpB\@  
/* Df_W>QC  
**FileAccess.java &`7~vA&c  
*//文件访问(定位,写) (vIrXF5Dnj  
package NetFox; I3Sl>e(Z  
import java.io.*;  1fbd/-h  
0/.#V*KM  
ArkFC  
public class FileAccessI implements Serializable{ ixJUq o  
-_jV.`t  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 inBd.%Yr  
RandomAccessFile oSavedFile; H*QN/{|RU  
long nPos; mRCgKW<  
R|Ft@]  
=#XsY,r  
public FileAccessI() throws IOException A!v-[AI[  
{ CiP-Zh[gZ  
this("",0); @S~'m;  
} }iy`Ko+B"b  
$ql-"BB  
_ED1".&#f  
public FileAccessI(String sName,long nPos) throws IOException (.,E6H|zI  
{ GS{:7%=j  
oSavedFile = new RandomAccessFile(sName,"rw"); 6RZ[X[R[}  
this.nPos = nPos; v)JQb-<  
oSavedFile.seek(nPos); D} 0>x~  
} :C42yQAP  
&QOob)  
FH8?W| G  
public synchronized int write(byte[] b,int nStart,int nLen) }\u~He%  
{ TJY$<:  
int n = -1; 98C~%+  
try{ [Hdk=p  
oSavedFile.write(b,nStart,nLen); , IUMH]D  
n = nLen; NrvS/ cI!t  
} \3q{E",\>@  
catch(IOException e) m@JU).NKCS  
{ ;hs:wLVa"  
e.printStackTrace (); 6\86E$f=h  
} 2h&pm   
;J\{r$q  
BN4dr9T  
return n; )<.S 3  
} wrG*1+r  
#)R;6"  
s)=L6t^a6  
} lGB7(  
#py7emu  
>/n5=RWh  
/* V`69%35*@  
**SiteInfoBean.java se_zCS4Y  
*/ ^F?H)[0  
package NetFox; _0F6mg n  
iy tSC  
MbnV5b:X  
public class SiteInfoBean { zi>f436-  
~s^&*KaA  
[ur/`   
private String sSiteURL; //Site's URL mC~W/KReA  
private String sFilePath; //Saved File's Path c%~'[W04\  
private String sFileName; //Saved File's Name `@.YyPxX\  
private int nSplitter; //Count of Splited Downloading File svpWABO  
! # tRl  
Lu:!vTRmw  
public SiteInfoBean() q\#3G  
{//nSplitter的缺省值为5 @7lZ{jV$  
//default value of nSplitter is 5 jZv8X 5i  
this("","","",5); 8zj09T[  
} l^`!:BOtR  
Wr)% C  
>mF`XbS  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8KWT d  
{ |[34<tIN  
sSiteURL= sURL; C,PCU<q  
sFilePath = sPath; Rl5}W\&  
sFileName = sName; M/V >25`  
this.nSplitter = nSpiltter; +G/~v`Bv  
3"[ KXzn  
M`?/QU~  
} LR)is  
\yG_wZs  
f`Wfw3  
public String getSSiteURL() tu!u9jVv  
{ 56<LMY|d  
return sSiteURL; kj0A%q#'}  
} z5'VsK:  
'&<-,1^L  
He!0&B\7h  
public void setSSiteURL(String value) Xkv>@7ec  
{ #gN{8Yk>  
sSiteURL = value; ]Vwky]d  
} G|O"Kv6  
W>@%d`>o5  
L0&!Qct  
public String getSFilePath() RM<\bZPc  
{ M2xUs  
return sFilePath; bkOm/8k|4  
} j|aT`UH03  
}4 $EN  
-nk%He  
public void setSFilePath(String value) G~esSL^G/  
{ J"83S*2(j  
sFilePath = value; 0_]aF8j  
} +V'r >C:  
},Z -w_H  
BK /;H G  
public String getSFileName() df J7Dhn  
{ Ej34^*m9k  
return sFileName; a|s=d  
} [\.>BK  
gdG: &{|x  
ONfJ"Rp3  
public void setSFileName(String value) +$ -#V   
{ b&_p"8)_  
sFileName = value; oNCDG|8z  
} t o?"{  
hXr vb[6  
pP/o2  
public int getNSplitter() }bnkTC  
{ X r)d;@yi  
return nSplitter; pH~JPNng  
} gRqz8UI  
ZRQPOy  
!CMN/=  
public void setNSplitter(int nCount) |y=gp  
{ YJL=|v  
nSplitter = nCount; X1'Ze,34  
} ud#8`/!mq  
} &1u ?W%(Px  
O0{v`|w9+  
RCX4;,DHx  
/* B+B v(p  
**Utility.java qnm9L w#  
*/ 3}gK`1Nq1  
package NetFox; AN1bfF:C  
z`2d(KE?  
``z="oD  
public class Utility { 0,3 ':Df  
dk]ro~ [  
7> ]C2!  
public Utility() ~ dk1fh  
{ Ce)Wvuh  
UD(#u3z  
`dNb%f>  
} 7>mYD3  
vSL{WT]m  
//线程睡眠 h/VYH(Tj  
public static void sleep(int nSecond) ]s S oIT  
{ 2M1mdkP3  
try{ ky%%H;  
Thread.sleep(nSecond); Oxvw`a#  
} A&7jE:Ew  
catch(Exception e) `&6]P:_qp  
{ :)yM9^<D  
e.printStackTrace (); ^KF'/9S  
} S\rfR N  
} v;8XRR:  
lpM{@JC  
//日志 Smu x&e  
public static void log(String sMsg) fh 3 6  
{ $3Ia+O   
System.err.println(sMsg); gc:>HX );)  
} c8s/`esA  
qs b4@jt+  
>dGYZfqD  
public static void log(int sMsg) 4>HGwk@+8  
{ sP |i '  
System.err.println(sMsg); CUG<v3\  
} tSYnc7  
}  M:$nL  
}.vy|^X  
s#fmGe"8  
/* <>oW f  
**TestMethod.java iau&k `b`  
*/ R}Y=!qjYE=  
package NetFox; :F\f}G3  
E;Hjw0M'k  
<coCu0  
public class TestMethod { Ye6O!,R  
HXQ rtJ  
u5_fM*Ka  
public TestMethod() 5b'S~Qj#r$  
{ ///xx/weblogic60b2_win.exe qsRh ihPX  
try{ Sx"I]N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); d!:SoZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `y#C%9#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \nWpV7TSN  
fileFetch.start(); A&'%ou  
} 8IH gsW";  
catch(Exception e){e.printStackTrace ();} I2T2'_I  
k#&SWp=  
.#J3UZ  
} co80M;4  
YLo$n  
M[{:o/]<  
public static void main(String[] args) 1aG}-:$t'  
{ ZM?r1Z4  
new TestMethod(); ]l'ki8  
} {@%(0d{n}  
} >cb gL%  
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