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http断点续传简单实现(java)

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/* 6( ~DS9  
**SiteFileFetch.java *=~X1s  
*/ otSF8[  
package NetFox; DNp4U9  
import java.io.*; TkjPa};R  
import java.net.*; L |pJ\~  
|@lVFEl]  
:eR[lR^4*  
public class SiteFileFetch extends Thread { Mz:t[rfs  
r\f|r$i  
ypA)G/;  
SiteInfoBean siteInfoBean = null; //文件信息Bean NX5NE2@^qH  
long[] nStartPos; //开始位置 uom~, k$|  
long[] nEndPos; //结束位置 /ar/4\b  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _!'sj=n]q  
long nFileLength; //文件长度 Kj`sq":Je0  
boolean bFirst = true; //是否第一次取文件 0Q= o"@  
boolean bStop = false; //停止标志 GK.U_`4?  
File tmpFile; //文件下载的临时信息 8~s-@3J  
DataOutputStream output; //输出到文件的输出流 AcCM W@e  
`h+1u`FJ  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) u, Rhm-`  
public SiteFileFetch(SiteInfoBean bean) throws IOException Vo-]&u&cr  
{ 4}t&AW4  
siteInfoBean = bean; v*.#LJEm  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2`]_c=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q=|0lZ$`V_  
if(tmpFile.exists ()) 2xJT!lN  
{ my(yN|  
bFirst = false; 9b}AZ]$  
read_nPos(); 8G0DuMI5  
} TR([u  
else JHCV7$RS  
{ lS:R##  
nStartPos = new long[bean.getNSplitter()]; B>TI dQ  
nEndPos = new long[bean.getNSplitter()]; qf qp}g\  
} Y =BXV7\  
af WEt -  
oL 69w1  
bAl0z)p  
} 7Yjxx+X9  
05>xQx?"m4  
FII>6c  
public void run() R.+yVO2  
{ {<_9QAS  
//获得文件长度 iTq~ ^9G  
//分割文件 hm5A@Z   
//实例FileSplitterFetch )xMP  
//启动FileSplitterFetch线程 8;r7ksE~  
//等待子线程返回 Q, !b  
try{ >5|;8v-r  
if(bFirst) x# &ZGFr~  
{ At#'q>Dn  
nFileLength = getFileSize(); rH<iUiA?O  
if(nFileLength == -1) `Wf)qMb  
{ |UO&18Y7-  
System.err.println("File Length is not known!"); }M I9?\"q  
} G3G"SJ np  
else if(nFileLength == -2) aF'9&A;q  
{ \I4*|6kA  
System.err.println("File is not access!"); 8'kA",P  
} jSj (ZU6  
else }Pj3O~z  
{  9g*MBe:  
for(int i=0;i<nStartPos.length;i++) R{"7q:-  
{ q;kN+NK64  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [-bT_X  
} vKX $Nf  
for(int i=0;i<nEndPos.length-1;i++) wPl!}HNf  
{ o5N];Nj  
nEndPos = nStartPos[i+1]; M!s@w%0?'  
} \q8D7/q  
nEndPos[nEndPos.length-1] = nFileLength; =lf&mD _/  
} Hkv4t5F  
} U*' YGv  
L|3wG Y9E  
 t : =  
//启动子线程 "lp),  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fi[c^e+IX  
for(int i=0;i<nStartPos.length;i++) O_p:`h:;M  
{ oR=^NEJv  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ass8c]H@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <Dr*^GX>?  
nStartPos,nEndPos,i); ,cvLvN8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gJy Ft8Z<  
fileSplitterFetch.start(); QPH2TXw  
} M-2:$;D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "$Wi SR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <9S?wju4W'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", KJwkkCE/=  
nEndPos = " + nFileLength); I]`>m3SJ  
// fileSplitterFetch[nPos.length-1].start(); ~[i,f0O,  
z:aT5D  
COw]1 R  
//等待子线程结束 9 GdrJ~h  
//int count = 0; S!GjCog^J  
//是否结束while循环 'U)|m  
boolean breakWhile = false; #pxc6W /  
+|OkT  
Bu'PDy~W,  
while(!bStop) / 4K*iq  
{ EX[X|"r   
write_nPos(); j/bebR}X  
Utility.sleep(500); sBuVm<H  
breakWhile = true; g#V3u=I8~  
d0b--v/  
2O|o%`?  
for(int i=0;i<nStartPos.length;i++) $ ;/Ny)"  
{ G6zFCgFJ^y  
if(!fileSplitterFetch.bDownOver) gz[Ng> D+  
{ V 'Gi2gNaP  
breakWhile = false; @NXGVmY1}  
break; qVFz-!6b  
} Q^v8n1  
} <G59>H5  
if(breakWhile) a$MMp=p  
break; ^c1I'9(r5  
s &v<5W2P  
>qn@E?Uf  
//count++; }TRr*] P<%  
//if(count>4) W|T"'M_  
// siteStop(); .ukP)rGe  
} H{x}gBQ  
unmuY^+<  
n>\BPiz  
System.err.println("文件下载结束!"); `}F=Zjy  
} twx8TQ9  
catch(Exception e){e.printStackTrace ();} ij6ME6  
} c7IgndVAV  
jow^~   
\PzC:H  
//获得文件长度 &_&])V)<\S  
public long getFileSize() `X]-blHo  
{ F'Fc)9qFa<  
int nFileLength = -1; WjGv%^?  
try{ J%xp1/= 2  
URL url = new URL(siteInfoBean.getSSiteURL()); .9 WUp>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M6!kn~  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~aH*ZA*f  
5/mW:G,&  
"HVwm>qEi  
int responseCode=httpConnection.getResponseCode(); B[-%A!3 F  
if(responseCode>=400) Z>a_vC  
{ d {moU\W  
processErrorCode(responseCode); kT UQ8U  
return -2; //-2 represent access is error 9U58#  
} /U)w:B+p/g  
K4xZT+Qb  
%yQ-~T@  
String sHeader; *ZGQ`#1.X6  
mCtuyGY  
)xP]rOT  
for(int i=1;;i++) ~@z5Ld3xz  
{ @P"q`*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )G ,LG0"-  
//Utility.log(in.readLine()); Z8k O*LYv  
sHeader=httpConnection.getHeaderFieldKey(i); QA.B.U7!  
if(sHeader!=null) < V"'j  
{ .F)b9d[?  
if(sHeader.equals("Content-Length")) '[5tc fG#z  
{ F& H~JJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); h|%d=`P,  
break; %M9^QHyo@  
} [}lv!KmzW  
} n=t%,[Op  
else *NDLGdQqz  
break; v{=-#9-4 &  
} Q%QpG)E  
} X!,Ngmw.  
catch(IOException e){e.printStackTrace ();} -H.;73Kb[  
catch(Exception e){e.printStackTrace ();} #>~$`Sg  
h&yaug,.  
Y*f7& '[  
Utility.log(nFileLength); >K-O2dry*  
c.&vWmLSGE  
jRB:o?S  
return nFileLength; cY#TH|M  
} zv#i\8h^p  
3 %dbfT j  
d&?B/E^  
//保存下载信息(文件指针位置) /R k5n  
private void write_nPos() 3Luv$6  
{ :":W(O  
try{ OU9=O>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0+r/>-3]  
output.writeInt(nStartPos.length); 4_t aCK  
for(int i=0;i<nStartPos.length;i++) Z/;rM8[{&  
{ wC=IN   
// output.writeLong(nPos); K N0S$nW+  
output.writeLong(fileSplitterFetch.nStartPos); ;=)CjC8)  
output.writeLong(fileSplitterFetch.nEndPos); xvp{F9~qT  
} #JuO  
output.close(); 'L3 \I  
} &r DOqj  
catch(IOException e){e.printStackTrace ();} 66)@4 3V  
catch(Exception e){e.printStackTrace ();} _BtlO(0&  
} ,[Cl'B  
[b;Oalw  
Ylt[Ks<2  
//读取保存的下载信息(文件指针位置) %F&j B  
private void read_nPos() g:;v]   
{ S3qUzK  
try{ g"C$B Fc  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); r7ywK9UL  
int nCount = input.readInt(); tk}qvW.Ii  
nStartPos = new long[nCount]; ,*S?L qv^  
nEndPos = new long[nCount]; \~y>aYy  
for(int i=0;i<nStartPos.length;i++) -zc9=n<5  
{ z^}T= $&  
nStartPos = input.readLong(); #|$i H kVY  
nEndPos = input.readLong(); yo (&~r  
} |[o2S90  
input.close(); r*+9<8-ZX<  
} &% M^:WT  
catch(IOException e){e.printStackTrace ();} 0U`Ic_.  
catch(Exception e){e.printStackTrace ();} Jz%&-e3  
} :?RK>}4|F  
S~Q7>oNm  
Z/beROW)  
private void processErrorCode(int nErrorCode) =/dW5qy;*+  
{ sSD(mO<(  
System.err.println("Error Code : " + nErrorCode); IUc!nxF#  
} 3\mFK$#sr  
i,4JS,82I  
7BI0g@$Nn]  
//停止文件下载 R>gj"nB  
public void siteStop() y-sQ"HPN  
{ yuI5# VUS  
bStop = true; E/s3@-/  
for(int i=0;i<nStartPos.length;i++) &nz1[,  
fileSplitterFetch.splitterStop(); f+I*aBQ  
X:62 )^~'  
8<.KWr  
} wau81rSd  
} 79x^zqLb  
//负责部分文件的抓取 *^.b}K%  
**FileSplitterFetch.java -BoN}xE4  
*/ I}k!i+Yl  
package NetFox; &|{K*pNa  
 6f1;4Jfp  
*ZaK+ B  
import java.io.*; g_n=vO('X  
import java.net.*; OvK_CN{  
C|!E' 8Rw  
>Q+EqT  
public class FileSplitterFetch extends Thread { |qbJ]v!  
k+i}U9c"  
NqF-[G<  
String sURL; //File URL mup3ua]!  
long nStartPos; //File Snippet Start Position h{PLyWH  
long nEndPos; //File Snippet End Position ojIh;e  
int nThreadID; //Thread's ID 4 &|9304<H  
boolean bDownOver = false; //Downing is over "lmiGR*u  
boolean bStop = false; //Stop identical 5utj$ha2  
FileAccessI fileAccessI = null; //File Access interface gWWy!H  
z6{0\#'K  
v"$; aJ  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &kO4^ A  
{ Xq)'p8C?  
this.sURL = sURL; >nr1|2  
this.nStartPos = nStart; {g )kT_  
this.nEndPos = nEnd; Vq<|DM3z<  
nThreadID = id; 0q`'65 lx  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2RE }l=h5  
} le[5a=e(  
t}oxHEa V  
eq4<   
public void run() e|4jT7L}  
{ y|lP.N/  
while(nStartPos < nEndPos && !bStop) UoKBcarm  
{ vNtbb]')m  
+ZZiZ&y  
ZcdS?Z2k  
try{ 3G>E>yJ  
URL url = new URL(sURL); ?tSY=DK\n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;w6\r!O,  
httpConnection.setRequestProperty("User-Agent","NetFox"); u YH{4%  
String sProperty = "bytes="+nStartPos+"-"; $x2<D :  
httpConnection.setRequestProperty("RANGE",sProperty); vF([mOZ  
Utility.log(sProperty); 0cS.|\ZTA  
`$#64UZ>U1  
-#Wc@\;  
InputStream input = httpConnection.getInputStream(); K1+,y1c  
//logResponseHead(httpConnection); m=}kGzIY4  
@wa/p`gj5w  
km|~DkJ\a`  
byte[] b = new byte[1024]; NKI&n]EO  
int nRead; c2F`S1Nu<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P)}:lTe  
{ mGY 74>/  
nStartPos += fileAccessI.write(b,0,nRead); { aB_t%`w  
//if(nThreadID == 1) (sl]%RjGa  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); iu1iO;q  
} _*`AGda  
Y5npz^i  
m[8#h(s*t  
Utility.log("Thread " + nThreadID + " is over!"); -u9{R\S  
bDownOver = true; @\q~OyV  
//nPos = fileAccessI.write (b,0,nRead); <]!IC]+  
} 8vP d~te  
catch(Exception e){e.printStackTrace ();} Aw|3W ]  
} '$U"RP^(  
} <Jvr mm[  
j5HOdy2  
dm 2_Fj  
//打印回应的头信息 Q,DumOq  
public void logResponseHead(HttpURLConnection con) t)v#y!Ci"  
{ sP&E{{<QTF  
for(int i=1;;i++) 4^i*1&"  
{ P.fgt>v]  
String header=con.getHeaderFieldKey(i); f~U|flL^  
if(header!=null) ~O|0.)71]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gT+/CVj R  
Utility.log(header+" : "+con.getHeaderField(header)); Mz{>vb  
else My1E@<  
break; ahf$#UQLb  
} @a3<fmJ  
} *Js<VR  
:g\qj? o  
d6n6= [*  
public void splitterStop() |0bSxPXn!  
{ xGH%4J\  
bStop = true; 3NJH"amk  
} :@3d  
onmO>q*  
vLC&C-f  
} zzx4;C",u  
[NFAdE  
~/.&Z`ls  
/* 0FW=8hFp,  
**FileAccess.java ~KNxAxyVi  
*//文件访问(定位,写) 3&zmy'b*:  
package NetFox; f2Slsl;  
import java.io.*;   C[Fh^  
zZ wD)p?_g  
3 (<!pA  
public class FileAccessI implements Serializable{ \:#b9t{B-  
8<G@s`*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 v0y7N_U5n  
RandomAccessFile oSavedFile; {B}0LJIpL  
long nPos; Ay_<?F+&  
Gm%[@7-  
K0#tg^z5d  
public FileAccessI() throws IOException 0I&rZMpF&  
{ ht-6_]+ME  
this("",0); kOjq LA  
} qI"mW@G~H  
&0l Nj@/  
kP6r=HH@  
public FileAccessI(String sName,long nPos) throws IOException l&yR-FJ7KY  
{ <)&ykcB  
oSavedFile = new RandomAccessFile(sName,"rw"); JxWHrsh[  
this.nPos = nPos; bH.">IV  
oSavedFile.seek(nPos); 4EELaP|%  
} HWd,1  
D"Xm9 (  
Jw^+t)t  
public synchronized int write(byte[] b,int nStart,int nLen) p\HXE4d'  
{ 2<O hO ^  
int n = -1; 1ERz:\  
try{ jgYiuM3c\  
oSavedFile.write(b,nStart,nLen); $@NZ*m%?JQ  
n = nLen; N7;2BUIXJ  
} M-Js"cB[  
catch(IOException e) Pf!K()<uJ  
{ 4VooU [Ka(  
e.printStackTrace (); FD6|>G  
} x=Ru@nK;  
1TVTP2&Rd  
BAPi<U'D  
return n; "-Ns1A8  
} J>'o,"D  
hb_Ia]b  
RWoiV10  
} x O)nS _I  
7}#vANm  
78Gvc~j  
/* %iGME%oXr  
**SiteInfoBean.java e 9:l  
*/ $`Ou*  
package NetFox; {L+?n*;CA  
l(`w]=t&  
bT;C8i4b\H  
public class SiteInfoBean { g &za/F  
;aF / <r  
:{fsfZXXr  
private String sSiteURL; //Site's URL q4Z \y  
private String sFilePath; //Saved File's Path J3'"-,Hv  
private String sFileName; //Saved File's Name QVP $e`4  
private int nSplitter; //Count of Splited Downloading File CeZ5Ti?F  
Q A%GK4F70  
|9Y9pked8  
public SiteInfoBean() 0I cyi#N  
{//nSplitter的缺省值为5 >Kr,(8rA  
//default value of nSplitter is 5 z(m*]kpL"  
this("","","",5); vS X 6~m  
} D"o>\Q  
]EK"AuEz`  
mrJQB I+  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) o1Xk\R{  
{ m$o|s1t  
sSiteURL= sURL; hsl8@=_ B  
sFilePath = sPath; _ 9k^Hd[L$  
sFileName = sName; W$3p,VTMmB  
this.nSplitter = nSpiltter; ?T^$,1 -  
1"'//0 7  
$v^F>*I1  
} "qF&%&#r'  
[$./'-I]  
@wg*~"d  
public String getSSiteURL() Y,8M[UIK  
{ $HH(8NoL  
return sSiteURL; *s!8BwiE  
} _ x7Vyy5  
:4WwCpgz,  
Y3-P*  
public void setSSiteURL(String value) H p,r @  
{ 2M;{|U  
sSiteURL = value; mr/^lnO  
} 1xx-}AIH#  
T.{I~_  
tVe*J@i\$  
public String getSFilePath() ,:#prT[P"  
{ K.cNx  
return sFilePath; <1@_MY o  
} GJW1|Fk  
E:i3 /Ep?  
KctD=6  
public void setSFilePath(String value) ^C'k.pV n~  
{ 4Q]+tXes  
sFilePath = value; "_(o% \"7  
} kL&^/([9  
v/^2K,[0>  
y/PEm)=Tt  
public String getSFileName() n3)g{K^  
{ ~U^0z|.  
return sFileName; # v v k7  
} -_2= NA?t  
4];NX  
h)YqC$A-s  
public void setSFileName(String value) q<7Nz] Td  
{ yx-{}Yj^  
sFileName = value; LAr6J  
} YY.;J3C  
2=#O4k.@  
`R; ct4-  
public int getNSplitter() {g);HnmPN  
{ :H?p^d e  
return nSplitter; p?!] sO1l  
} r3KV.##u,  
*mBEF"  
51rM6 BT  
public void setNSplitter(int nCount) NfN#q:w1  
{ $GYy[-.`  
nSplitter = nCount; ]];7ozS)X  
} ]{y ';MZ  
} C 4n5U^  
!|`YNsR  
=GLsoc-b  
/*  @P~ u k  
**Utility.java S>'wb{jj!  
*/ qV(Plt%  
package NetFox; 3rWqt  
-m__I U  
}X AoMp  
public class Utility { )`U T#5  
pZWp2hj{X  
.AV--oA~  
public Utility() Tn-H8;Hg  
{ 3FS:]|oC  
ha(hG3C  
HFf| >&c&  
} ]])i"oew  
HDC`g  
//线程睡眠 )kd PAw  
public static void sleep(int nSecond) b|xz`wUH0$  
{ >`lf1x  
try{ ?49wq4L;a  
Thread.sleep(nSecond); PS6G 7  
} 1&m08dZm5  
catch(Exception e) {)Gh~~57_W  
{ [,fMh $t  
e.printStackTrace (); PPmZ[N9(;  
} !>! l=Z  
} QALMF rWH  
pM4 j=F  
//日志 "Pu P J|  
public static void log(String sMsg) .2u%;)S  
{ yJgnw6>r2  
System.err.println(sMsg); zZA I"\;W  
} I]} MK?  
7-(tTBH  
(apAUIE  
public static void log(int sMsg) $YW z~^f  
{ jCy2bE  
System.err.println(sMsg); %5uuB4P&|$  
} =b; v:HC  
} c[Y7tj%y  
O[-wm;_(=*  
ZL@7Mr!e  
/* )ll}hGS  
**TestMethod.java MEo+S  
*/ Ib!`ChZ  
package NetFox; !.F`8OD`u  
 ) .#,1  
(I\aGGW  
public class TestMethod { fPspJug  
C~:aol i;  
{)`5*sd  
public TestMethod() &hZcj dB  
{ ///xx/weblogic60b2_win.exe =n$,Vv4A  
try{ 6KV&E8Gn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (?~F}u v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |>p\*Dl}H  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  g\n@(T$)  
fileFetch.start(); 9}5Q5OZ  
} vL-%"*>v  
catch(Exception e){e.printStackTrace ();} jd~r~.y  
f9#B(4Tgi  
BPC$ v\a  
} g*8sh  
)L^WD$"'Q  
:e gSW2"5S  
public static void main(String[] args) whvM^  
{ `oq 3G }  
new TestMethod(); /(vT49(]  
} x!Wl&  
} 5vY1 XZt{  
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