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http断点续传简单实现(java)

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/* K-$gTV  
**SiteFileFetch.java ~-+lZ4}  
*/ %ZF6%m0S  
package NetFox; *$ZLu jy7  
import java.io.*; HvWnPh1l  
import java.net.*; Ns6Vf5T.  
83*"58  
jk0Ja@8PK  
public class SiteFileFetch extends Thread { Fe(qf>E  
5feCA ,v7  
R3]Ra&h6N)  
SiteInfoBean siteInfoBean = null; //文件信息Bean m6P!#=a:l<  
long[] nStartPos; //开始位置 &n% 3rC5{  
long[] nEndPos; //结束位置 tHhA _  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,q yp2Y7  
long nFileLength; //文件长度 |w(@a:2 kw  
boolean bFirst = true; //是否第一次取文件 LbGyD;#_  
boolean bStop = false; //停止标志 c&Pgz~iP  
File tmpFile; //文件下载的临时信息 ^O cM)Z6h  
DataOutputStream output; //输出到文件的输出流 W/O&(t  
UR~9*`Z ,  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) lGa'Y  
public SiteFileFetch(SiteInfoBean bean) throws IOException anj*a<C<  
{ ^(p}hSLAfQ  
siteInfoBean = bean; K0xZZ`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); kLKd O0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dP(*IOO.  
if(tmpFile.exists ()) K!q:A+]  
{ 1mw<$'pm0  
bFirst = false; ~=5vc''  
read_nPos(); ~F`t[p  
} Re <G#*^  
else M[ea!an  
{ Ku{DdiTg>  
nStartPos = new long[bean.getNSplitter()]; L]o 5=K  
nEndPos = new long[bean.getNSplitter()]; ?XVJ$nzW  
} utq*<,^  
C LhD[/Fo  
z5CZ!"&v  
:^mfTj$  
} NGHzifaE   
(,<ti):  
J[:3H6%`  
public void run() (ilU<Ht  
{ F`9;s@V*  
//获得文件长度 @P:  
//分割文件 W{\){fr6O  
//实例FileSplitterFetch ;mV,r,\dH  
//启动FileSplitterFetch线程 v%|()Z0  
//等待子线程返回 2nOoG/6 E  
try{ *yGOm i  
if(bFirst) >r7{e:~q  
{ n237%LH[  
nFileLength = getFileSize(); CErkmod{}e  
if(nFileLength == -1) J7R+|GTcx  
{ :F:<{]oG_  
System.err.println("File Length is not known!"); RltG/ZI  
} 'J^E|1P  
else if(nFileLength == -2) C[$uf  
{ )1H$5h  
System.err.println("File is not access!"); N{@kgc  
} ^Bihm] Aq  
else @b=b>V[d6  
{ 8S1%;@c  
for(int i=0;i<nStartPos.length;i++) CtwMMZXX3  
{ |[x) %5F  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %Uk]e5Hu  
} Z7&Bn  
for(int i=0;i<nEndPos.length-1;i++) zmI?p4,  
{ XfF Z;ul  
nEndPos = nStartPos[i+1]; C% <[mM  
} 2U6j?MyH2  
nEndPos[nEndPos.length-1] = nFileLength; yi3@-  
} @>'.F<:P<  
} K;2tY+I  
vVF#]t b|  
4*9y4"  
//启动子线程 /ey[cm2#[s  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9V&%_.Z  
for(int i=0;i<nStartPos.length;i++) FJ3Xeo s4|  
{ $l:?(&u  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pmAir:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5fS89?/?  
nStartPos,nEndPos,i); jp2AU,Cl  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )J+vmY~&  
fileSplitterFetch.start(); iq`y  
} zzfwI@4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r=dFk?8XbC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); S86%o,Saq\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", uY;-x~Z  
nEndPos = " + nFileLength); 7SE=otZ>  
// fileSplitterFetch[nPos.length-1].start(); 7>EjP&l  
IMzhEm  
eRllF` *  
//等待子线程结束 EAq/Yw2$  
//int count = 0; LV{a^!f`y  
//是否结束while循环  }5^j08  
boolean breakWhile = false; j'i-XIs  
d [z+/L  
:0pxacD"!  
while(!bStop) ^ MkT">  
{ 6.|f iQs ]  
write_nPos(); fRJSo%  
Utility.sleep(500); s%`o  
breakWhile = true; b w5|gmO  
6Gjr8  
NS "hdyA  
for(int i=0;i<nStartPos.length;i++) Ftj3`Mu  
{ S~`& K  
if(!fileSplitterFetch.bDownOver) w5|az6wZB!  
{ d|5u<f5  
breakWhile = false; /EhojODMF  
break; pLL ^R  
} Dq+rEt  
} 67 >*AL  
if(breakWhile)  L's_lC  
break; C^RO@kM  
NMY~f (x  
uD_|/(  
//count++; 39?iX'*p  
//if(count>4) T$13"?sr=  
// siteStop(); '.oEyZA;o  
} f+Nq?GvwBQ  
CDei+ q  
'6u;KIG  
System.err.println("文件下载结束!"); I'G$:GX  
} o9~Z! &p  
catch(Exception e){e.printStackTrace ();} KcP86H52I  
} ZbCu -a{v  
DGdSu6s$  
~q#UH'=%  
//获得文件长度 zLue j'  
public long getFileSize() Zr'VA,v  
{ ihKnZcI$i  
int nFileLength = -1; y1^<!I  
try{ NvXds;EC  
URL url = new URL(siteInfoBean.getSSiteURL()); VN|P(S6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R<)7,i`F  
httpConnection.setRequestProperty("User-Agent","NetFox"); YVZm^@ZVV  
GWRKiTu9  
6w<jg/5t  
int responseCode=httpConnection.getResponseCode(); ]1rr$f9  
if(responseCode>=400) RUm1;MWs  
{ Fsv%=E{  
processErrorCode(responseCode); 31k.{dnm  
return -2; //-2 represent access is error C/ow{MxA  
} 9f;\fe  
| "DQ^)3Pi  
Q u2W  
String sHeader; 21M@z(q*  
/og2+!  
l,HMm|oU  
for(int i=1;;i++) azz6_qk8  
{ u\-xlp?"o  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ( du<0J|PT  
//Utility.log(in.readLine()); D_`MeqF}C  
sHeader=httpConnection.getHeaderFieldKey(i); tlu-zUsi  
if(sHeader!=null) PoY+Y3  
{ >F6'^9|  
if(sHeader.equals("Content-Length")) e?3 S0}  
{ D#508{)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); UyBI;k^]  
break; W"YFx*W  
} t.c XrX`k  
} &%L1n?>Q}  
else ^rjICF e  
break; \kZxys!4  
} cF3V{b|bU  
} y^=\w?d  
catch(IOException e){e.printStackTrace ();} &V$_u#<  
catch(Exception e){e.printStackTrace ();} (}vi"mCeW  
bNp RGhlV  
a_w# ,^/P  
Utility.log(nFileLength); l~Hs]*jm  
?8fa/e  
v/\l  
return nFileLength; :CNWHF4$  
} ZY+NKb_  
4StiYfae  
0RN]_z$;H  
//保存下载信息(文件指针位置) z%(m:/N70  
private void write_nPos() 9a"[-B:  
{ `] ;*k2  
try{ ^aN;M\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?SRG;G1  
output.writeInt(nStartPos.length); kJq8"Klg  
for(int i=0;i<nStartPos.length;i++) xq- R5(k  
{ 4!,x3H'  
// output.writeLong(nPos); #GT/Q3{C  
output.writeLong(fileSplitterFetch.nStartPos); ir-srVoXy  
output.writeLong(fileSplitterFetch.nEndPos); )8p FPr  
} 4*d$o=wa  
output.close(); (e S4$$g  
} &z8@  rk|  
catch(IOException e){e.printStackTrace ();} x6\EU=,  
catch(Exception e){e.printStackTrace ();} Y` Oz\W  
} ,IF3VE&r  
i[sHPEml(5  
vdAaqM6D  
//读取保存的下载信息(文件指针位置) ='a[(C&Y  
private void read_nPos() q asbK:}  
{ thIuK V{CO  
try{ BSYJ2   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Pqli3(  
int nCount = input.readInt(); 3#`_t :"A  
nStartPos = new long[nCount]; S*VG;m #  
nEndPos = new long[nCount]; ?%dsY\  
for(int i=0;i<nStartPos.length;i++) ET;YAa*  
{ C;];4[XR  
nStartPos = input.readLong(); d5T M_ C  
nEndPos = input.readLong(); ~CCRs7V/L  
} 1p=^I'#  
input.close(); Md mS  
} {.qeVE{  
catch(IOException e){e.printStackTrace ();} G?)NDRM  
catch(Exception e){e.printStackTrace ();} <]xGd!x$  
} _>+!&_h  
q@8Jc[\d  
=~6A c}$  
private void processErrorCode(int nErrorCode) 6^y*A!xY  
{ s(jixAf  
System.err.println("Error Code : " + nErrorCode); j\k|5 ="w-  
} ;NQ9A &$)  
9z6-HZG'~<  
g|ewc'y  
//停止文件下载 5&Al  
public void siteStop() W{:^P0l  
{ gpDH_!K  
bStop = true; 4v9jGwnzt  
for(int i=0;i<nStartPos.length;i++) /5 yjON{  
fileSplitterFetch.splitterStop(); &u&+:m  
X)^eaw]Q0  
wd*8w$\  
} 9"hH2jc  
} + 2 v6fan  
//负责部分文件的抓取 15dhr]8E  
**FileSplitterFetch.java pW$ZcnU  
*/ Ey96XJV  
package NetFox; V,:^@ 7d  
~A^E_  
dZ}gf}.v  
import java.io.*; @i2"+_}*  
import java.net.*; /iURP-rl  
3'tcEFkH  
_#32hAI  
public class FileSplitterFetch extends Thread { p_%dH  
HR'sMu3  
P t< JF  
String sURL; //File URL U[7 &   
long nStartPos; //File Snippet Start Position S v3O${B|  
long nEndPos; //File Snippet End Position w3l2u1u  
int nThreadID; //Thread's ID OBY^J1St  
boolean bDownOver = false; //Downing is over )+ifVv50  
boolean bStop = false; //Stop identical HXV4E\JA  
FileAccessI fileAccessI = null; //File Access interface &JMp)zaI[  
:Y wb  
8LuM eGs  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >}<1  
{ SFqY*:svOw  
this.sURL = sURL; 8R|!$P  
this.nStartPos = nStart; h;" 9.  
this.nEndPos = nEnd; W D8  
nThreadID = id; j=|cx+nb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 p1t qwV  
} IE*eDj  
h pf,44Kg  
c_"=G#^9@i  
public void run() 0b=1Ce+0q  
{ 3Ye{a<ckK  
while(nStartPos < nEndPos && !bStop) _EPfeh;  
{ ;::]R'F[  
|m{u]9  
@vyq?H$U;N  
try{ YoDL/  
URL url = new URL(sURL); ri.}G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); phCItN;  
httpConnection.setRequestProperty("User-Agent","NetFox"); aF8'^xF  
String sProperty = "bytes="+nStartPos+"-"; B|WM;Y^  
httpConnection.setRequestProperty("RANGE",sProperty); H@, h$$  
Utility.log(sProperty); +G: CR,Z>+  
6_mkt|E=  
i?{)o]i  
InputStream input = httpConnection.getInputStream(); KXrZ:4bg  
//logResponseHead(httpConnection); j xc^OsYj  
_:+hB9n s  
*Aqd["q  
byte[] b = new byte[1024]; L(RI4d  
int nRead; W kP`qD3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) trx y3k;  
{ 6W\G i>  
nStartPos += fileAccessI.write(b,0,nRead); LX'z7fh  
//if(nThreadID == 1) m&MAA^I  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [?>\]  
} &&PXWR!%]  
-v %n@8p  
px${ "K<  
Utility.log("Thread " + nThreadID + " is over!"); .9NYa|+0  
bDownOver = true; n2A ; `=  
//nPos = fileAccessI.write (b,0,nRead); {,+{,Ere  
} WuuF &0?8C  
catch(Exception e){e.printStackTrace ();} '3|fv{I  
} { )g $  
} S( ^HIJK  
MCO2(E-  
,ZV>"'I:  
//打印回应的头信息 7Is:hx|:  
public void logResponseHead(HttpURLConnection con) ]9 $iUA%Ef  
{ a^o'KN{  
for(int i=1;;i++) LvqWA}  
{ )FpizoVq0  
String header=con.getHeaderFieldKey(i); *fCmZ$U:{  
if(header!=null) q0C%">>1 #  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d/Sw.=vq  
Utility.log(header+" : "+con.getHeaderField(header)); @WCA 7DW!  
else nEt{ltsS0  
break; ;Zm-B]\  
} h6b(FTC^  
} H)k V8wU  
QHXA?nBX  
baoyU#X9  
public void splitterStop() +)hxYLk&I  
{ uf^HDr r<L  
bStop = true; `r'$l<(4WV  
} =`ZRPA!aY  
hmkm^2  
=Y-.=}jp;  
} 5OCt Q4u  
$b~[>S-Q  
2@N9Zk{{J  
/* ZsNZ3;d@u(  
**FileAccess.java Z EK,Z['  
*//文件访问(定位,写) OO2uE ;( 3  
package NetFox; S]&:R)#@  
import java.io.*; n$ rgJ  
Xub*i^(]  
u69UUkG  
public class FileAccessI implements Serializable{ O dbXna  
ff;~k?L  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 esiU._:u  
RandomAccessFile oSavedFile; D0Mxl?S?  
long nPos; &,P; 7R  
a&2UDl%K  
I_m3|VCa|t  
public FileAccessI() throws IOException 5Gs>rq" #  
{ [D+,I1u2h  
this("",0); fGd1  
} ppo0DC\>  
9 JhCSw-<)  
u`ry CZo#g  
public FileAccessI(String sName,long nPos) throws IOException k;B[wEW@  
{ ]$u C~b   
oSavedFile = new RandomAccessFile(sName,"rw"); A`#?Bj   
this.nPos = nPos; eBH:_Ls_-^  
oSavedFile.seek(nPos); dF[|9%)  
} d>?C?F  
9Fy 'L#%  
HSWki';G  
public synchronized int write(byte[] b,int nStart,int nLen) {+m8^-T  
{ ,CI-IR2  
int n = -1; a>6D3n W  
try{ Q6HghG  
oSavedFile.write(b,nStart,nLen); #UE}JR3g  
n = nLen; 'ieTt_1.G  
} !Rc %  
catch(IOException e) cQ]c!G|a4  
{ k'_f?_PBu  
e.printStackTrace (); h% KEg667  
} r.'xqzF/  
@ x .`z  
; Xf1BG r  
return n; c`/VYgcTqB  
} soLW'8  
9%Tqk"x?  
Zs]n0iwM'@  
} {sf ,(.W  
HUMy\u84H  
gV-*z}`U  
/* u]Q}jqiq"  
**SiteInfoBean.java +;\w'dBi,  
*/ }K={HW1>  
package NetFox; sE'c$H  
b*(K;`9)B  
8Ji`wnkXe  
public class SiteInfoBean { j^5YFUwsQg  
[-VK! 9pQ  
Qu1&$oO  
private String sSiteURL; //Site's URL v)T# iw[  
private String sFilePath; //Saved File's Path B~E">}=!  
private String sFileName; //Saved File's Name @dk-+YxG  
private int nSplitter; //Count of Splited Downloading File Vz$xV!  
M(nzJ  
 ?HRS*  
public SiteInfoBean() "-djA,`  
{//nSplitter的缺省值为5 Pro?xY$E)  
//default value of nSplitter is 5 %.hJDX\j  
this("","","",5); up+0-!AH  
} dOKp:|9G  
<{k`K[)  
ZG 0^O"B0  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6}m`_d?  
{ Lu {/"&)  
sSiteURL= sURL; G^tazAEfo  
sFilePath = sPath; :'B(DzUR  
sFileName = sName; SzIzQR93&  
this.nSplitter = nSpiltter; Q 8Hl7__^  
PDPK|FU  
P))BS  
} p5$}h,7  
[.^ol6  
&9^4- 5]  
public String getSSiteURL() +WAkBE/  
{ S't9F  
return sSiteURL; .hu7JM+  
} 9DJ&J{2W  
zt: !hM/Vt  
S9Oz5_x  
public void setSSiteURL(String value) Dm{Xd+Y  
{ o5p{ O>D[z  
sSiteURL = value; O-HS)g$2  
} &BLCP d  
J}&Us p  
,{!,%]bC  
public String getSFilePath() :>.{w$Ln%  
{ "d:rPJT)(@  
return sFilePath; W03mdRW  
} 1$eoW/8.  
F$DA/{.D  
bJetqF6 n  
public void setSFilePath(String value) X5YOxMq  
{ t$(#$Z,RS  
sFilePath = value; CDM6o!ur3  
} _\KFMe= PV  
WM`3QJb  
COsmVQ.  
public String getSFileName() d_d&su E  
{ =TDKU  
return sFileName; ~1D^C |%  
} r) x  
bwzx_F/  
&muBSQ-  
public void setSFileName(String value) ru@#s2  
{ PkrVQH9^w  
sFileName = value; U!o7Nw@ z  
} ;.Bz'Q  
ns%gb!FBJX  
:-}K:ucaj  
public int getNSplitter() pe vXixl  
{ {o5|(^l  
return nSplitter; k7Bh[ ..!  
} )`rD]0ua;  
I4G0 !"T+  
 y Ne?a{  
public void setNSplitter(int nCount) 5aizWz  
{ T8a' 6otc  
nSplitter = nCount; y<kUGsD  
} RbL?(  
} ,Q56A#Y\  
@KK6JyOTQ  
U}5fjY  
/* =}#yi<Lt  
**Utility.java JY2<ECO  
*/ `jGeS[FhR  
package NetFox; xcr2|  
GMJ4v S  
0TmEa59P  
public class Utility { $KYGQP  
WVRIq'  
>t3_]n1e  
public Utility() VKl,m ;&N  
{ )vS0Au^C~  
RFL * qd4  
e&;e<6l&{  
} ]0."{^ksL  
uK@d?u!`  
//线程睡眠 Ob/)f)!!  
public static void sleep(int nSecond) y017 B<Ou  
{ 6?F88;L  
try{ &N^~=y^`C'  
Thread.sleep(nSecond); _ l|%~  
} IFTNr2I  
catch(Exception e) 20V~?xs~  
{ Zu,:}+niU  
e.printStackTrace (); %PYO9:n  
} :s_> y_=g  
} K>DN6{hnV;  
j**[[  
//日志 vHf)gi}O|  
public static void log(String sMsg) =$J(]KPv!?  
{ 4CF;>b f~  
System.err.println(sMsg); -5b|nQuY  
} =@Oo3*>  
\:4*h  
)k=KLQ\b  
public static void log(int sMsg) :')[pO_FW*  
{ ]gq)%T]  
System.err.println(sMsg); oh8:1E,I  
} @e)}#kN.  
} f256;3n  
X%'z  
_/LGGt4&%  
/* f\hMTebma$  
**TestMethod.java ]?4;Lw  
*/ A0Mjk  
package NetFox;  pX_#Y)5  
t Ly:F*1i  
^xa, r#N:V  
public class TestMethod { R'v~:wNTNs  
&IQ=M.!r  
uI-T]N:W8x  
public TestMethod() 2|>\A.I|=  
{ ///xx/weblogic60b2_win.exe 9~Dg<wQ  
try{ z ?\it(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); KQPu9f9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @PvO;]]%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); o^@"eG$,  
fileFetch.start(); 'GJB9i+a^  
} \C3I6Qx  
catch(Exception e){e.printStackTrace ();} XYo,5-  
!kE5]<H\  
5!F;|*vC8  
} E%`J =C}  
p/<DR |  
]lC%HlID  
public static void main(String[] args) Xfc$M(a K{  
{ (L/>LZn|  
new TestMethod(); &'z_:Wm  
} UTkPA2x  
} }/a%-07R  
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