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http断点续传简单实现(java)

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/* OwPHp&{ Y  
**SiteFileFetch.java D5({&.X[-  
*/ 8z7eL>)  
package NetFox; PhV/WjCZ  
import java.io.*; X8}\m%gCU  
import java.net.*; YlT&.G  
5Ma."?rW   
4p+Veo6B  
public class SiteFileFetch extends Thread { Z]WX 7d  
1zG6^U  
RRYcg{g  
SiteInfoBean siteInfoBean = null; //文件信息Bean ut]UU*g^$  
long[] nStartPos; //开始位置 N !ay#V  
long[] nEndPos; //结束位置 ,UC|[-J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 m\CU,9;;(  
long nFileLength; //文件长度 6R8>w,  
boolean bFirst = true; //是否第一次取文件 R]Z#VnL@qz  
boolean bStop = false; //停止标志 !>ZBb\EyK  
File tmpFile; //文件下载的临时信息 f x4#R(N  
DataOutputStream output; //输出到文件的输出流 s]`6u yW"  
n@h$V\&\iM  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `F1Yfm jZT  
public SiteFileFetch(SiteInfoBean bean) throws IOException yS:w>xU @<  
{ |+JO]J#bc  
siteInfoBean = bean; )c1Pj#|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); R/fE@d2~In  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); u rQvJ  
if(tmpFile.exists ()) ]Ol w6W?%  
{ 6(t'B!x  
bFirst = false; CS*lk!C  
read_nPos(); uOKD#   
} bG*l_  
else ^&y*=6C  
{ bivo7_  
nStartPos = new long[bean.getNSplitter()]; J}4RJ9  
nEndPos = new long[bean.getNSplitter()]; &'i>d&  
} p\#;(pf}s  
'rFLG+W  
[+CFQf>  
/X0<2&v  
} l x0BKD?n  
L0H^S)g  
:SO4@JT{W  
public void run() -:Fr($^  
{ b"}ya/  
//获得文件长度 O'^AbO=,  
//分割文件 Oml3=TV  
//实例FileSplitterFetch [T)>RF  
//启动FileSplitterFetch线程 B-L@ 0gH  
//等待子线程返回 Q>;Aq!mr=  
try{ oRcP4k;d=  
if(bFirst) %}-ogi/c  
{ wv\"(e7(  
nFileLength = getFileSize(); r4gLoHD)  
if(nFileLength == -1) y?3u6q++  
{ `('Up?  
System.err.println("File Length is not known!"); EG &me  
} W>?aZv  
else if(nFileLength == -2) g2}aEfp!H  
{ "Wk K1u  
System.err.println("File is not access!"); 4AvIU!0w  
} Z\QN n  
else 3m21n7F4*  
{ Sx Bo%  
for(int i=0;i<nStartPos.length;i++)  ;0$qT$,  
{ 9^C6ZgNS  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); f*hnzj  
} *!Gb_!98  
for(int i=0;i<nEndPos.length-1;i++) ;[g~h |{6  
{ Eg&Q,dH[  
nEndPos = nStartPos[i+1]; 4\ )WMP  
} 'u%_Ab_H  
nEndPos[nEndPos.length-1] = nFileLength; iWUxB28  
} 2\O!vp>|-  
} x 0vW9*&  
i!JSEQ_8  
f4dHOH  
//启动子线程 prIJjy-F  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2JeEmG9  
for(int i=0;i<nStartPos.length;i++) [!} uj`e  
{ Kuk@x.~0m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yTe25l{QaF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LS# _K-  
nStartPos,nEndPos,i); #L*MMC"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [5M!'  
fileSplitterFetch.start(); VzcW9'"#  
} +:c}LCI9<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yd45y}uS;F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +, rm  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v] Xy^7?  
nEndPos = " + nFileLength); n4"xVDL  
// fileSplitterFetch[nPos.length-1].start(); 3z#fFP@E  
AI9=?X<kh  
u+jx3aP:  
//等待子线程结束 I3l1 _  
//int count = 0; bOV]!)o  
//是否结束while循环 Nii5},  
boolean breakWhile = false; Ur""&@  
z!~{3M  
}y*rO(cu7G  
while(!bStop) ?ia O6HD  
{ N a.e1A&?j  
write_nPos(); [f$pq5f='  
Utility.sleep(500); &mA{_|>  
breakWhile = true; z^%`sUgP  
RcI0n"Gi_  
%V!!S#W  
for(int i=0;i<nStartPos.length;i++) : :/vDUDc  
{ lx82:_  
if(!fileSplitterFetch.bDownOver) )hK;27m4  
{ MSt@yKq  
breakWhile = false; Z$)jPDSr  
break; %.{xo.`a[  
} |l?*' =  
} k9&pX8#  
if(breakWhile) PC!X<C8*  
break; U/rFH9e$  
AIA4c"w.EO  
_9iF`Q  
//count++; ]U 1S?p  
//if(count>4) h#|Ac>fz  
// siteStop(); sNC~S%[  
} gkx<<)y l  
-N2m|%B  
-PiZvge  
System.err.println("文件下载结束!"); %9t=Iu*  
} .8CfCRq  
catch(Exception e){e.printStackTrace ();} q&wv{  
} EixAmG  
f{D~ZC.*  
<bBgevL+_K  
//获得文件长度 GIUyW  
public long getFileSize() !t&C,@Ox  
{ Lez]{%+.`[  
int nFileLength = -1; )Vx C v  
try{ l-[5Zl;"  
URL url = new URL(siteInfoBean.getSSiteURL()); r9^~I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NX<Q}3cC  
httpConnection.setRequestProperty("User-Agent","NetFox"); S'AS,'EnY  
6uWPIM;  
i$'#7U  
int responseCode=httpConnection.getResponseCode(); 28xLaob  
if(responseCode>=400) ~NO'8 Mr  
{ 3:!5 ]  
processErrorCode(responseCode); BOW`{=  
return -2; //-2 represent access is error z8w@pT  
} 7!8R)m^1[  
xa%2w]  
mDIN%/S'  
String sHeader; =$vy_UN  
B+=Xb;p8  
\YF'qWB  
for(int i=1;;i++) 1f5;^T I  
{ th|TwD&mO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4= hz4(5a  
//Utility.log(in.readLine()); YR68'Sft[  
sHeader=httpConnection.getHeaderFieldKey(i); GG`;c?d@  
if(sHeader!=null) 6C*4' P9>  
{ jR,3 -JQ  
if(sHeader.equals("Content-Length")) Jb` yK@x  
{ k.#[h@Pm  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); p/&s-G F  
break; 5%XEybc2  
} .^?Z3iA",  
} 1`EkN0iZ  
else fmk(}  
break; @)Sd3xw[  
} * n>YS  
} BQ77 n2(@  
catch(IOException e){e.printStackTrace ();} tumYZ)nW  
catch(Exception e){e.printStackTrace ();} P;l D ri  
>]l7AZ:,  
u=!n9W~"  
Utility.log(nFileLength); <o&\/uO~H  
TInp6w+u  
 Wwo`R5  
return nFileLength; (C8r^m|A  
} $T}Dn[.  
% KmhR2v  
{DGnh1  
//保存下载信息(文件指针位置) *[wj )  
private void write_nPos() ~px)Jd  
{ WzO[-csy  
try{ n%:&N   
output = new DataOutputStream(new FileOutputStream(tmpFile)); ;"D I)hd z  
output.writeInt(nStartPos.length); &<S]=\  
for(int i=0;i<nStartPos.length;i++) "Bbd[ZI8  
{ {}v<2bS  
// output.writeLong(nPos); RB/;qdqR  
output.writeLong(fileSplitterFetch.nStartPos); 2o9IP>#u  
output.writeLong(fileSplitterFetch.nEndPos); D,;6$Pvg^  
} FPXB>D'  
output.close(); 23[XmBf  
} 1c03<(FCd  
catch(IOException e){e.printStackTrace ();} 7e`h,e=  
catch(Exception e){e.printStackTrace ();} L k]/{t0  
} 0@PI=JZ%  
5QJ FNE  
BpZ17"\z  
//读取保存的下载信息(文件指针位置) )qV&sru.$  
private void read_nPos() LDv>hzo  
{ )1S"D~j-  
try{ `?xE-S ;Pn  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5Gsjt+ o  
int nCount = input.readInt(); 8 n)3'ok  
nStartPos = new long[nCount]; Nc[V kJ]  
nEndPos = new long[nCount]; ,O ]AB  
for(int i=0;i<nStartPos.length;i++) 2*@.hBi  
{ 5!^DKyw:  
nStartPos = input.readLong(); RI64QD  
nEndPos = input.readLong(); 1q;r4$n  
} 05Go*QvV  
input.close(); rA#Ji~  
} Cu +u'&U!  
catch(IOException e){e.printStackTrace ();} M-+= t8  
catch(Exception e){e.printStackTrace ();} piKR*|F  
} DANndXQLH  
07tSXl5!  
{oc7Chv=/H  
private void processErrorCode(int nErrorCode) 23=SXA!  
{ ,}_uk]AQ  
System.err.println("Error Code : " + nErrorCode); n"c3C)  
} &26H   
I &I q  
AT]Ty  
//停止文件下载 JPfE`NZ  
public void siteStop() TZ+2S93c  
{ `h|>;u   
bStop = true; 1$G'Kg/  
for(int i=0;i<nStartPos.length;i++) X-=J7G`\h#  
fileSplitterFetch.splitterStop(); 1(12`3  
;Q} H'Wg,  
4 Gm(P~N  
} d9sqO9Ud8  
} t.E3Fh!o  
//负责部分文件的抓取 bZsg7[: C  
**FileSplitterFetch.java z@n779i  
*/ f.SmCgG  
package NetFox; =3?"s(9  
SR\F2@u  
P",E/beV  
import java.io.*; {Lm%zdk*k  
import java.net.*; ;NzS;C'  
Nt#a_  
lKF<]25  
public class FileSplitterFetch extends Thread { o{&UT VyGs  
6 C|]Fm  
'uOzC"_yF  
String sURL; //File URL iNAaTU  
long nStartPos; //File Snippet Start Position HfgK0wIi  
long nEndPos; //File Snippet End Position =q-HR+  
int nThreadID; //Thread's ID Rr>h8Ni <  
boolean bDownOver = false; //Downing is over hPHrq{YZ  
boolean bStop = false; //Stop identical @|GKNW#  
FileAccessI fileAccessI = null; //File Access interface d~b#dcv$"  
{<3>^ o|"  
#UpxF?A(  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException SMdkD]{g  
{ {Q la4U  
this.sURL = sURL; T>;Kq;(9  
this.nStartPos = nStart; ^."HD(  
this.nEndPos = nEnd; d4#Ra%   
nThreadID = id; 2dF:;k k  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 op%?V :  
} [d_sd  
_("&jfn  
sR1 &2hB  
public void run() CxOBH89(  
{ Lx"a#rZ  
while(nStartPos < nEndPos && !bStop) sC .R.  
{ >%D=#}8l@  
k5@_8Rc  
)*Qa 9+ :  
try{ |e@Bi#M[  
URL url = new URL(sURL); G Riu]   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h8yv:}XU*  
httpConnection.setRequestProperty("User-Agent","NetFox"); HGgw<Os-k  
String sProperty = "bytes="+nStartPos+"-"; ] cv|A^  
httpConnection.setRequestProperty("RANGE",sProperty); drQioH-  
Utility.log(sProperty); PUN.nt  
'd"\h#  
nAp7X-t  
InputStream input = httpConnection.getInputStream(); !\NKu1ta  
//logResponseHead(httpConnection); adJoT-8P6  
,QpDz{8  
"Jp6EL%  
byte[] b = new byte[1024]; ]rh)AE!Y(  
int nRead; DT=!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i`g>Y5   
{ Te{L@sj  
nStartPos += fileAccessI.write(b,0,nRead); $Q:5KNF+p  
//if(nThreadID == 1) X |f'e@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o4kNDXP#S  
} / N@0qQ  
pg~`NN  
} V4"-;P  
Utility.log("Thread " + nThreadID + " is over!");  *ihg'  
bDownOver = true; |7zm!^t$  
//nPos = fileAccessI.write (b,0,nRead); ubhem(p#  
}  <C4^Vem  
catch(Exception e){e.printStackTrace ();} EMH?z2iGd  
} `.dTkL  
} ^}8_tZs8\  
f ( `.q  
)^!-Aj\x  
//打印回应的头信息 U[S;5xeF.j  
public void logResponseHead(HttpURLConnection con) ^;YD3EZw  
{ i[ BR"(  
for(int i=1;;i++) 2|~& x~  
{ ?<  w +{  
String header=con.getHeaderFieldKey(i); "VWxHRVg4M  
if(header!=null) >?e*;f$VdJ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); e_6 i896  
Utility.log(header+" : "+con.getHeaderField(header)); JoZC+G  
else xuelo0h,  
break; "0L@cOyG  
} /]xd[^  
} j.C C.[$g  
YA^9, q6u?  
CSU>nIE0  
public void splitterStop() $zCUQthL@  
{ $)@zlnU  
bStop = true; HIh oYSwB  
} >[xQUf,p  
I{cn ,,8  
ecf7g)+C  
} xDr *|d  
1'_OM h*;  
t*Q12Q  
/* fWm;cDM H  
**FileAccess.java wq]nz!  
*//文件访问(定位,写) y i@61XI  
package NetFox; dl{3fldb  
import java.io.*; Mdwh-Cis/  
lQ+-g#`  
. ~|^du<X  
public class FileAccessI implements Serializable{ <{-DYRiN  
dy`~%lX?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1xtbhk]D  
RandomAccessFile oSavedFile; Vxgc|E^J  
long nPos; ^U_jeAuk8[  
kLD)<D  
;pB?8Z  
public FileAccessI() throws IOException E/GI:}YUy_  
{ m d C. FO-  
this("",0); \+Cp<Hv+  
} */8\Z46z  
@pko zE-  
&(.ZHF  
public FileAccessI(String sName,long nPos) throws IOException R a*9d]N@  
{ BLJ-' 8G  
oSavedFile = new RandomAccessFile(sName,"rw"); "J{,P9P6  
this.nPos = nPos; 5d4-95['_  
oSavedFile.seek(nPos); -=qmYf  
} f CVSVn"o  
jN {ED_  
 b'{D4/  
public synchronized int write(byte[] b,int nStart,int nLen) P7Y[?='v  
{ \|&5eeE@  
int n = -1; )O&$-4gL'  
try{ U&eLj"XZ  
oSavedFile.write(b,nStart,nLen); Ns 9g>~  
n = nLen; MoF Z  
} |]]fcJOBP  
catch(IOException e) xjX5PQu  
{ OIWo* %  
e.printStackTrace (); $4M3j%S  
} Lq&xlW j  
oD}I{&=wa  
L|H{;r'  
return n;  z`_N|iEd  
} da<1,hF  
FP\[7?ZLn  
?QMs<  
} A=3 U4L  
@LmUCP~  
QTyl=z7  
/* $ `ho+  
**SiteInfoBean.java . }1!MK5  
*/ BW*zj=N%  
package NetFox; >%[W2L\'  
hmi15VW  
[j/-(?+  
public class SiteInfoBean { (nzzX?`nY  
D6m>>&E['  
Gce_gZH7{  
private String sSiteURL; //Site's URL j"dbl?og  
private String sFilePath; //Saved File's Path < <xJ-N  
private String sFileName; //Saved File's Name e'?(`yW>  
private int nSplitter; //Count of Splited Downloading File {oZ]1Qf_  
PQs9@]w[  
2KX *x_-   
public SiteInfoBean() }$UFc1He\J  
{//nSplitter的缺省值为5 Av[jFk  
//default value of nSplitter is 5 C^~iz in  
this("","","",5); BxG;vS3>*e  
} `<Ftn  
K4tX4U[Z  
>ylVES/V  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >9klh-f  
{ = G_6D  
sSiteURL= sURL; j?,$*Fi  
sFilePath = sPath; 0jyokER  
sFileName = sName; 2,fB$5+  
this.nSplitter = nSpiltter; R3<+z  
$200?[  
Owr`ip\  
} G@;aqe[dB  
p[$I{F*a  
Z~R i%XG  
public String getSSiteURL() O//e0?]W  
{ #-`lLI:w0  
return sSiteURL; WZr~Pb9  
} K XGs'D  
c2U>89LlZ  
ZA P+jX;  
public void setSSiteURL(String value) F,bl>;{[{  
{ A4^+p0@  
sSiteURL = value; 8?$2;uGL  
} nGt8u4gcP  
w*}9;l  
l1??b  
public String getSFilePath() : )z_q!$j  
{ :s5g6TR  
return sFilePath; O<hHo]jLF  
} 3,[2-obmi  
pA2U+Q@  
j0GI[#  
public void setSFilePath(String value) Dz{e@+>M  
{ YJy*OS_&  
sFilePath = value; 9NT;^K^ I  
} i_MI!o  
\x!>5Z Y  
LWI~m2  
public String getSFileName() @FTi*$Ix  
{ cNVdGY%&  
return sFileName; 1 W0;YcT]  
} 0D'Wr(U(  
TU/J]'))C  
aPC!M4#  
public void setSFileName(String value) ~g{,W  
{ )=D&NO67Pq  
sFileName = value; b>i=",i\  
} nqBu C  
/\#5\dHj  
8syo_sC |  
public int getNSplitter() @K9T )p]  
{ No7Q,p  
return nSplitter; Y[!a82MTzn  
} ]Q3Gj@6  
8VZ-`?p  
zCHr  
public void setNSplitter(int nCount) x3Ud0[(  
{ zgqw*)C~  
nSplitter = nCount; P5>CSWy%  
} TI>yi ^}  
} tX251S  
@>Keu\)  
x}{VHp`|ld  
/* h,x]  
**Utility.java fDd!Mt  
*/ <IVz mzpL  
package NetFox; yShHFlO=  
0REWbcxd"  
K>[H@|k\k  
public class Utility { 5)UmA8"zVB  
CC\z_C*P-p  
K\b O[J  
public Utility() +HX'AC  
{ +]-KzDsr"V  
lIz_0rE  
))`Zv=y"  
} 9^u?v`!  
qN@a<row&~  
//线程睡眠 o!~bR  
public static void sleep(int nSecond) to3J@:V8e  
{ d<'xpdxc  
try{ |Z ,G  
Thread.sleep(nSecond); Q7|13^ |C  
} !qlGt)G3  
catch(Exception e) mB{{o}'<u  
{ ??Zmj:8E'  
e.printStackTrace (); X}(0y  
} ?^~"x.<nr  
} yUO|3ONT  
{ ZX C%(u  
//日志 PoJ$%_a}  
public static void log(String sMsg) $hSZ@w|IF  
{ :,m)D775S  
System.err.println(sMsg); BuTIJb+Q\  
} H |UL5<:]D  
%z~U@Mka  
^d80\PXz  
public static void log(int sMsg) :eW~nI.Vc  
{ hli 10p$  
System.err.println(sMsg); QIK73^  
} pGY]Vw Y  
} ?Z>.G{Wm@  
"!tw ,Gp  
6[.Mx}h6  
/* X:lPWz!7{  
**TestMethod.java L]d@D0.Z  
*/ N;'HR)  
package NetFox; s.`d<(X?  
T3./V0]\I  
8[)]3K x  
public class TestMethod { y.p6%E_`  
fm%RNAPvc  
7 Zt\G-QV  
public TestMethod() gvNZrp>e!  
{ ///xx/weblogic60b2_win.exe -j_I_  
try{ :(>9u.>l?5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -l H>8+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .dT;T%3fO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xGfD z*t  
fileFetch.start(); 87KrSZ  
} c^O#O  
catch(Exception e){e.printStackTrace ();} z,FTsR$x  
8e!DDh  
pYl{:uIPN8  
} 1?|6odc  
b$O_L4CP  
9K':Fn2,  
public static void main(String[] args) lt6;*z[  
{ UZP6x2:=  
new TestMethod(); _i[)$EgFm  
} 2BDan^:-Av  
} DBJA}Cw  
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