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http断点续传简单实现(java)

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/* @72x`&|I?u  
**SiteFileFetch.java ";PG%_(  
*/ `OKo=e~,  
package NetFox; 5%<TF .;-J  
import java.io.*; 7$(_j<o`  
import java.net.*; 'FShNY5  
t|;%DA)fjw  
j\2] M  
public class SiteFileFetch extends Thread { 44|deE3Z  
2?GXkPF2;A  
bnijM/73  
SiteInfoBean siteInfoBean = null; //文件信息Bean sS, zzx<  
long[] nStartPos; //开始位置 o"|O ]  
long[] nEndPos; //结束位置 .aNO( /kO  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7w "sJ  
long nFileLength; //文件长度 f5@.^hi[  
boolean bFirst = true; //是否第一次取文件 p QluGIX0V  
boolean bStop = false; //停止标志 [J~aAB  
File tmpFile; //文件下载的临时信息 z*6$&sS\>  
DataOutputStream output; //输出到文件的输出流 ZV!R#Xv  
'sj9[o@]  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) sf Dg/ a  
public SiteFileFetch(SiteInfoBean bean) throws IOException &&;ex9  
{ P?^JPbfV  
siteInfoBean = bean; mT96 ]V \  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eh$G.-2N  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); XjX 2[*l  
if(tmpFile.exists ()) +.w[6  
{ @. "q  
bFirst = false; gf+o1\5t@  
read_nPos(); F?7u~b|@{  
} xb%/sz(4  
else Ay 2b,q  
{ uu}'i\Q  
nStartPos = new long[bean.getNSplitter()]; 8{oZi]ob  
nEndPos = new long[bean.getNSplitter()]; F4Rr26M  
} );=Q] >  
Q}=fVY  
4 GUA&qs  
,1,&b_  
} <z,+Eg  
'r~8  
rB,ldy,f  
public void run() >gr<^$  
{ C?,*U  
//获得文件长度 M3ZOk<O<R  
//分割文件 Q\H_t)-  
//实例FileSplitterFetch v' C@jsx M  
//启动FileSplitterFetch线程 +a-D#^ 2;  
//等待子线程返回 vyE{WkZxR  
try{ 5\WUoSgy  
if(bFirst) WhH!U0  
{ N8VVGPa  
nFileLength = getFileSize(); hje! w`  
if(nFileLength == -1) /w0sj`;"  
{ a_Jb> }  
System.err.println("File Length is not known!"); -!l^]MU  
} YNI;h%w  
else if(nFileLength == -2) 6;gLwOeOHY  
{ MZ WmlJ   
System.err.println("File is not access!"); xWDR72 6  
} z?)He)d  
else =LOk13l\"  
{ wZQ)jo7*g  
for(int i=0;i<nStartPos.length;i++) ^_sQG  
{ 0Q7MM6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sdrWOq  
} )AI?x@  
for(int i=0;i<nEndPos.length-1;i++) "TfI+QgLF  
{ <KX&zi<L)  
nEndPos = nStartPos[i+1]; i0\)%H:z  
} ?IILt=)<  
nEndPos[nEndPos.length-1] = nFileLength; iUTU*El>  
} f~q4{  
} L"^OdpOs  
5Dd:r{{ Q  
s"WBw'_<<  
//启动子线程 $C u R}g  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6x/s|RWL1  
for(int i=0;i<nStartPos.length;i++) }-74 f  
{ 9mDn KW  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "Kq>#I'%W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0'`S,  
nStartPos,nEndPos,i); 6lsEGe  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `"c'z;  
fileSplitterFetch.start(); `;$h'eI9  
} ->h5T%sn  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;g+]klR!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); KzNm^^#/$A  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", { D+Ym%n  
nEndPos = " + nFileLength); w.z<60%},0  
// fileSplitterFetch[nPos.length-1].start(); ~@D/A/|  
A @2Bs 5F  
e\D| o?v  
//等待子线程结束 U7h(-dV   
//int count = 0; a~opE!|m  
//是否结束while循环 P#MK  
boolean breakWhile = false; &<Zdyf?[Ou  
8eN7VT eb  
\x(^]/@  
while(!bStop) f}iU& 3S  
{ dw9T f^V  
write_nPos(); +P)ys#=  
Utility.sleep(500); {~'H  
breakWhile = true; u h )o  
CW p#^1F  
H O*YBL  
for(int i=0;i<nStartPos.length;i++) [9AM\n>g  
{ 'mE^5K  
if(!fileSplitterFetch.bDownOver) cDIBDC  
{ s6n`?,vw  
breakWhile = false; APq7 f8t  
break; @^&7$#jq%  
} mlB~V3M'G  
} moZm0` WR  
if(breakWhile) ~8{sA5y  
break; KP{3iUqvO  
_{)9b24(  
s$ z2 c  
//count++; N 9LgU)-Jt  
//if(count>4) uokc :D  
// siteStop(); /8c&Axuv  
} S)7/0N79A  
ix&'0IrX*  
lP3h<j  
System.err.println("文件下载结束!"); orqJ[!u)`  
} y' [LNp V  
catch(Exception e){e.printStackTrace ();} cU8xUpq  
} <cj{Qk  
Ryv_1gR!  
0` 5e  
//获得文件长度 I2[]A,f ,  
public long getFileSize() 'SV7$,mK@  
{  "r$/  
int nFileLength = -1; )];aIA$  
try{ tJ'iX>9I  
URL url = new URL(siteInfoBean.getSSiteURL()); snC/H G7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FnE6?~xa  
httpConnection.setRequestProperty("User-Agent","NetFox"); G3a7`CD  
wxdyF&U n  
:kG)sw7  
int responseCode=httpConnection.getResponseCode(); x-;`-Uo%  
if(responseCode>=400) t)a;/scT  
{ HdNnUDb$B  
processErrorCode(responseCode); !0" nx{7.  
return -2; //-2 represent access is error N'?u1P4G  
} bK*~ol  
H M:r0_  
T1bd:mC}n  
String sHeader; kO_5|6  
L l}yJ#3,  
K 1W].(-@4  
for(int i=1;;i++) KY.ZT2k  
{ 76@qHTh }  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); H=~9CJ+tc  
//Utility.log(in.readLine()); (MLhaux-  
sHeader=httpConnection.getHeaderFieldKey(i); +@:L|uFU  
if(sHeader!=null) , ;jGJr  
{ m3 -9b"  
if(sHeader.equals("Content-Length")) *9 D!A  
{ N`$!p9r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3WUH~l{UJ  
break; ,:GN;sIXg  
} *y]+dK&-  
} K{=PQ XSU  
else #/70!+J_UF  
break; (kw5>c7  
} 93o;n1rS  
} |He=LQ }0  
catch(IOException e){e.printStackTrace ();} "rNL `P7  
catch(Exception e){e.printStackTrace ();} SSA W52xC  
C5 X(U :  
|.U)ll(c  
Utility.log(nFileLength); q.V-LXM  
{y-^~Q"z  
rRb+_]Lg  
return nFileLength; ^?GmrHC)  
} y7lWeBnC  
[TTSA2  
z&}-8JykH  
//保存下载信息(文件指针位置) go'j/4Tp  
private void write_nPos() DBgMC"_   
{ ^jSsa  
try{ g0R[xOS|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `u_Qa  
output.writeInt(nStartPos.length); i.y)mcB4  
for(int i=0;i<nStartPos.length;i++) l=={pb  
{ 3z8C  
// output.writeLong(nPos); EL D!{bMT  
output.writeLong(fileSplitterFetch.nStartPos); JAjku6  
output.writeLong(fileSplitterFetch.nEndPos); \".^K5Pm  
} E>uVofhml  
output.close(); ,r^"#C0J}  
} 57I}RMT"  
catch(IOException e){e.printStackTrace ();}  jNyoN1M  
catch(Exception e){e.printStackTrace ();} #&8rcu;/  
} [V}, tO|  
iK;opA"  
CIC[1,  
//读取保存的下载信息(文件指针位置) Lx[ ,Z,kD  
private void read_nPos() diT=x52  
{ cgT  
try{ (< c7<_-H  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); = |U@  
int nCount = input.readInt(); WO*9+\[v  
nStartPos = new long[nCount]; LKF/u` 0dP  
nEndPos = new long[nCount]; e %O0hE  
for(int i=0;i<nStartPos.length;i++) k$i'v:c|:i  
{ 01@t~v3!Z  
nStartPos = input.readLong(); md Gwh7/3  
nEndPos = input.readLong(); 04@cLDX8uB  
} RHY4P4B<v>  
input.close(); -:Rp'SJ  
} EL{vFP  
catch(IOException e){e.printStackTrace ();} nt :N!suP3  
catch(Exception e){e.printStackTrace ();} 8Ogv9  
} F -gE<<  
9S7A!AKE  
h2q/mi5{  
private void processErrorCode(int nErrorCode) qUJ aeQ  
{ p( LZ)7/  
System.err.println("Error Code : " + nErrorCode); E-2 eOT  
} Y] g?2N=E  
aUopNmN  
vqdX^m^PY  
//停止文件下载 obH; g*  
public void siteStop() CI7A# 6-  
{ aaW]J mRb  
bStop = true; j<yiNHC  
for(int i=0;i<nStartPos.length;i++) j}JZ  
fileSplitterFetch.splitterStop(); q6d~V] 4:  
_e<o7Y@_  
T6BFX0$  
} A#y@`} ]!'  
} n6Z|Q@F  
//负责部分文件的抓取 `ldz`yu6++  
**FileSplitterFetch.java Me3dpF  
*/ mTDVlw0dh  
package NetFox; &, a3@i  
Fke//- R  
7<\C ?`q"  
import java.io.*; C(?blv-vM0  
import java.net.*; 5FeFN)  
@'2m$a  
t*S." q  
public class FileSplitterFetch extends Thread { hGTV;eU  
Xl-e !  
:l\V'=%9'@  
String sURL; //File URL J$ut_N):N  
long nStartPos; //File Snippet Start Position Lxl_"k G  
long nEndPos; //File Snippet End Position I:j3sy  
int nThreadID; //Thread's ID ~mz%E  
boolean bDownOver = false; //Downing is over =r. >N\  
boolean bStop = false; //Stop identical /F/;G*n  
FileAccessI fileAccessI = null; //File Access interface XP?rOOn  
ssQ BSbx  
%yS3&Ju  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3251Vq %  
{ H*I4xT@  
this.sURL = sURL; G;iEo4\?  
this.nStartPos = nStart; |UUdz_i!:  
this.nEndPos = nEnd; P5 <vf  
nThreadID = id; aoW6U{\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <yUstz,Xu^  
} L@Nu/(pB=  
N_C;&hJN$w  
4_?7&G0(  
public void run() 'fd1Pj9~$  
{ i b6^x:HGU  
while(nStartPos < nEndPos && !bStop) AONDx3[   
{ 2'0K WYM  
uKr1Z2  
|AZW9  
try{ mh/n.*E7  
URL url = new URL(sURL); 4Ft1@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "y?\Dx   
httpConnection.setRequestProperty("User-Agent","NetFox"); W&Y"K)`  
String sProperty = "bytes="+nStartPos+"-"; VyLH"cCv  
httpConnection.setRequestProperty("RANGE",sProperty); eDKxn8+(H  
Utility.log(sProperty); [#^#+ |{\  
E>jh"|f:{  
a}yXC<}$  
InputStream input = httpConnection.getInputStream(); g=@_Z"  
//logResponseHead(httpConnection); >pL2*O^{9  
q>!L6h5]t  
lEjwgk {  
byte[] b = new byte[1024]; /! ajsn  
int nRead; F'RUel_%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =3xE:  
{ QP@<)`1t9  
nStartPos += fileAccessI.write(b,0,nRead); iI1n2>V3y  
//if(nThreadID == 1) iPG0o %  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *~XA'Vw!  
} Kb ;dKQ  
/7c~nBU  
$rB3m~c|  
Utility.log("Thread " + nThreadID + " is over!"); :*514N  
bDownOver = true; ]jMKC8uz  
//nPos = fileAccessI.write (b,0,nRead); dtStTT  
} S^I,Iz+`S'  
catch(Exception e){e.printStackTrace ();} Dr<='Ux[5  
} k`KGB  
} <!d"E@%v@  
"8f?h%t  
j V3)2C}  
//打印回应的头信息 h!@,8y[B  
public void logResponseHead(HttpURLConnection con) JtKp(k&  
{ d50Vtm\  
for(int i=1;;i++) XKOUQc4!R  
{ vT^Sk;E  
String header=con.getHeaderFieldKey(i); Sb2v_o  
if(header!=null) + xv!$gJEj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); z`Wt%tL(  
Utility.log(header+" : "+con.getHeaderField(header)); :fcM:w&  
else c,EBF\r8*  
break; \/`?  
} =JLh?Wx  
} x+5k <Xi}  
SUCU P<G  
9Ru;`  
public void splitterStop() uLeRZSC  
{ 5v.DX`"  
bStop = true; d;[u8t  
} M5L{*>4|6  
R{Z-m2La  
kK>Xrj6  
} |iYg >  
zSTR^sgJ  
qeL pXe0c  
/* Ji'(`9F&a  
**FileAccess.java F'P Qqb{  
*//文件访问(定位,写) Lz9#A.  
package NetFox; 9;t]Hp_+K  
import java.io.*; M6|I6M<  
I_)*)d44_  
fN%jJ-[d  
public class FileAccessI implements Serializable{ >u +q1j.  
ZM#=`k9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _m E^rT  
RandomAccessFile oSavedFile; 9W7#u}Z  
long nPos; j|fd-<ng  
le)DgIT>=  
8ip7^  
public FileAccessI() throws IOException .Ce8L&cU  
{ OWjJxORB  
this("",0); . v)mZp  
} 0BPMmk  
IakKi4(  
`g ''rfk}  
public FileAccessI(String sName,long nPos) throws IOException 9<E g}Ic  
{ t G.(flW,  
oSavedFile = new RandomAccessFile(sName,"rw"); $P o}  
this.nPos = nPos; 'm=*u SJK  
oSavedFile.seek(nPos); H!IshZfktn  
} 5A Bhj*7  
[dX`K`k  
z2c5m  
public synchronized int write(byte[] b,int nStart,int nLen) M(q'%XL^  
{ 4EP<tV  
int n = -1; DC+wD Bp;  
try{ SS|z*h Z  
oSavedFile.write(b,nStart,nLen); 8y';\(;  
n = nLen; v`[Eb27W.  
} N^0uit  
catch(IOException e) i8X`HbmN  
{ ;Q0bT`/X  
e.printStackTrace (); =1;=  
} @ez Tbc3  
K ?$#nt p  
!<@J6??a}s  
return n; ^nK7i[yF.k  
} gYop--\14]  
]uL +&(cr  
Y$8JM  
} t%1^Li  
O;Y:uHf  
=nUW'  
/* [`=LTBt  
**SiteInfoBean.java &<'n^n  
*/ a?5[k}\  
package NetFox; i7[uLdQ  
`BFIC7a  
~:Uw g+]j  
public class SiteInfoBean { hPhZUL%  
2 +5e0/_V  
ZUXr!v/R:1  
private String sSiteURL; //Site's URL #%3rTU  
private String sFilePath; //Saved File's Path W1aa:hEf  
private String sFileName; //Saved File's Name "O>n@Q|  
private int nSplitter; //Count of Splited Downloading File 1r)kR@!LNG  
YA(@5CZ  
+ A_J1iJ<  
public SiteInfoBean() )x,8D ~p'  
{//nSplitter的缺省值为5 O{z}8&oR:  
//default value of nSplitter is 5 n";02?@F  
this("","","",5); ,"}Rg1\4t  
} 36m5bYMd)  
yI{5m^s{  
_A_ A$N~9  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p\v Mc\  
{ 2 -!L _W(  
sSiteURL= sURL; a@d=>CT$  
sFilePath = sPath; 9~IQw#<  
sFileName = sName; 0"k |H&  
this.nSplitter = nSpiltter; [p r"ZQ]  
Y]`.InG@  
6qvp*35Cx  
} E9! N>0  
N@o?b  
xh@-g|+g  
public String getSSiteURL() eBN)g^  
{ _#$9 y1bd  
return sSiteURL; bucR">_p  
} 7Ob*Yv=[  
u8zbYd3  
}}{!u0N},V  
public void setSSiteURL(String value) 6"j_iB  
{ {.e=qQ%P5)  
sSiteURL = value; :q##fG 'm/  
} woH)0v  
=/Aj  
%T`U^ Pnr  
public String getSFilePath() =wu*D5  
{ l?E a#  
return sFilePath; SJ' % ^  
} 7[v%GoE  
+m\|e{G  
{2'm^0Kl  
public void setSFilePath(String value) Jhkvd<L8`m  
{ 1MkI0OZE  
sFilePath = value; XhU@W}}  
} T".]m7!  
9$K;Raz%  
?0*8R K  
public String getSFileName() 9|' B9C  
{ }71LLzG`/  
return sFileName; /Poet%XvRx  
} (3vHY`9  
`RQ#.   
1,y&d}GW  
public void setSFileName(String value) y9Y1PH7G  
{ g{s'GyV8t  
sFileName = value; FXKF\1`( H  
} "HMP$)d  
nCg66-3A  
 EEy$w1ec  
public int getNSplitter() d4[(8} x$/  
{ Tq<2`*Qs  
return nSplitter; [}mA`5  
} @* 1U{`  
r WtZj}A  
=#5D(0Ab  
public void setNSplitter(int nCount) <T?oKOD ]  
{ OqhD7 +  
nSplitter = nCount; 6V9doP]i  
} z(RL<N%  
} ~K_Uq*dCE  
<{(/E0~V/<  
^o?SM^  
/* > Vb@[  
**Utility.java dHnR_.  
*/ 6" T['6:j  
package NetFox; k ^'f[|}  
?q2j3e[>  
UO`;&e-DB  
public class Utility { AtS;IRN@  
e`tLR- &  
l kIn%=Z  
public Utility() UK#&lim  
{ yKagT$-  
=?0lA_ 0  
}`VDD?M  
} <c[U#KrvJ  
wHjLd$ +o  
//线程睡眠 FwKj+f"  
public static void sleep(int nSecond) vZ7gS  
{ FaTa(3$%  
try{ tU wRE|_  
Thread.sleep(nSecond); G>qZxy`c  
} ".*x!l0y7  
catch(Exception e) co4h*?q  
{ n#Dv2 E=6  
e.printStackTrace (); gB,G.QM*6  
} :S@1  
} #(Or|\t  
Id'RL2Kq*&  
//日志 8cx=#Me  
public static void log(String sMsg) <hnCUg1  
{ l2%bF8]z  
System.err.println(sMsg); ]-o"}"3Ef  
} eg+!*>GaX  
1B>Vt*=  
I&9S;I$  
public static void log(int sMsg) _&3<6$}i"  
{ |iFVh$N  
System.err.println(sMsg); <3PL@orO  
} u),Qa=Wp  
} TjK{9A  
{npcPp9  
_#e&t"@GS  
/* v ]Sl<%ry  
**TestMethod.java gJt`?8t  
*/ Bc-yxjsw  
package NetFox; SZ![%)83  
S/vf'gj  
rtJl _0`  
public class TestMethod { tqPx$s  
q}uHFp/J  
W_O)~u8  
public TestMethod() a\uie$"cr]  
{ ///xx/weblogic60b2_win.exe /T^ JS  
try{ 5M]z5}n/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Hk_y/97OO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); v}G]X Z8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z7.|fE)<6  
fileFetch.start(); _?7#MWe&  
} C9n}6Er=,  
catch(Exception e){e.printStackTrace ();} >C WKH~  
5(2|tJw-H;  
"bg'@:4F  
} g3@Rl2yQJ  
;Lw{XqT  
M_ 0zC1  
public static void main(String[] args) 1xNVdI   
{ HJ?+A-n/  
new TestMethod(); $h9='0Wi0'  
} Uv_N x10  
} ~cAZB9Fa  
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