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http断点续传简单实现(java)

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/* )('%R|$ /  
**SiteFileFetch.java agjv{  
*/ wi4=OU1L)a  
package NetFox; 1RK=,Wx  
import java.io.*; ?r?jl;A&  
import java.net.*; UN zlN  
4\6N~P86  
iVd.f A  
public class SiteFileFetch extends Thread { (cN}Epi(D  
c05%iv  
rk7QZVE  
SiteInfoBean siteInfoBean = null; //文件信息Bean R,|d`)T  
long[] nStartPos; //开始位置 G(~;]xNW+  
long[] nEndPos; //结束位置 d1U\ft:gV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 yQ^($#Yk  
long nFileLength; //文件长度 <o+<H  
boolean bFirst = true; //是否第一次取文件 ~ug= {b  
boolean bStop = false; //停止标志 Nkp)Ax&  
File tmpFile; //文件下载的临时信息 6S+U&Ce\  
DataOutputStream output; //输出到文件的输出流 ]p;FZ4-T  
tkXEHsRT  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ;$a@J&  
public SiteFileFetch(SiteInfoBean bean) throws IOException mZx&Xez_G  
{ q*2N{  
siteInfoBean = bean; RTv qls  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lWqrU1Sjl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); # g_Bx  
if(tmpFile.exists ()) RB+N IoQQ|  
{ ]|sAK%/  
bFirst = false;  nv0]05.4  
read_nPos(); t`+'r}=d  
} h}]fn A  
else ~M\I;8ne  
{ J,zO2572u  
nStartPos = new long[bean.getNSplitter()]; 4"xPr[=iG  
nEndPos = new long[bean.getNSplitter()]; cCa|YW^j  
} NcP.;u;`  
{; .T7dL  
2D:fJ~|-[  
?c7*_<W5  
} |]aE<`D  
Zc!@0  
e'=MQ,EWd  
public void run() C-Ht(x|  
{ zkO<-w  
//获得文件长度 ] Puy!Q  
//分割文件 bd<m%OM""  
//实例FileSplitterFetch &NSY9'N,  
//启动FileSplitterFetch线程 Fr%d}g  
//等待子线程返回 #( 1j#\  
try{ b*FC\ :\  
if(bFirst) Le*.*\  
{ D`xHD#j h  
nFileLength = getFileSize(); vmLxkjUm#  
if(nFileLength == -1) zlMlMyG4  
{ W?PWJkIw  
System.err.println("File Length is not known!"); %gTVW!q  
} *R!]47Y d  
else if(nFileLength == -2) bA+[{  
{ 0Q3YN(  
System.err.println("File is not access!"); ;&`:|Hf*  
} <,-,?   
else 5 ZUy:  
{ y*|L:!   
for(int i=0;i<nStartPos.length;i++) nk>8SW^  
{ 4(sttd_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [iXi\Ex  
} ]c,l5u}A$  
for(int i=0;i<nEndPos.length-1;i++) K Dz]wNf  
{ O 'Am RJ  
nEndPos = nStartPos[i+1]; q-uLA&4  
} f~v"zT  
nEndPos[nEndPos.length-1] = nFileLength; , #Ln/;  
} #}j]XWy  
} _M&{^d  
P09,P  
'W+i[Ep5Q  
//启动子线程 @dl<-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \3: L Nt  
for(int i=0;i<nStartPos.length;i++) BUV/twU)  
{ cyHhy_~R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GM77Z.Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $&Ac5Zo%}  
nStartPos,nEndPos,i); A_]D~HH  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n8Q* _?Z/  
fileSplitterFetch.start(); vQcUaPm\$  
} ?}v}U^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m"q/,}DR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); N@}gLBf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", h\2}875  
nEndPos = " + nFileLength); >0 7shNX  
// fileSplitterFetch[nPos.length-1].start(); M!-q}5';  
:`;(p{  
^}tL nF  
//等待子线程结束 r /^'Xj'(  
//int count = 0; mUiOD$rO  
//是否结束while循环 nc- Qz  
boolean breakWhile = false; a&8l[xe1  
^b:Xo"q#H  
+fkP+RVY  
while(!bStop) s5nB(L*Pjp  
{ Pb3EnNqYbM  
write_nPos(); |E? ,xWN  
Utility.sleep(500); ~.FnpMDY  
breakWhile = true; j_(?=7Y3g  
(e 0_RQ  
jm4)gmC  
for(int i=0;i<nStartPos.length;i++) sK#H4y+<  
{ hl*MUD,  
if(!fileSplitterFetch.bDownOver) eS* *L 3  
{ ;r%<2(  
breakWhile = false; FF8WTuzB+  
break; hJ<:-u+yk}  
} R !jhwY$  
} _ \_3s  
if(breakWhile) f>|9 l  
break; j`{fB}  
 )Kxs@F  
#&}%70R)  
//count++; >s44  
//if(count>4) Io2,% !D  
// siteStop(); 8TUF w@H%  
} i'U,S`L6>  
;g&7*1E  
YmZC?x_{M2  
System.err.println("文件下载结束!"); G,+xT}@wu  
} sYl&Q.\q  
catch(Exception e){e.printStackTrace ();} bb*c+XN0  
} hT\p)w  
zwKg  
 ~WzMK  
//获得文件长度 ~}epq6L>  
public long getFileSize() 3O#~dFnp  
{ GU2]/\W*a  
int nFileLength = -1; owP6dtd)  
try{ o]dK^[/*  
URL url = new URL(siteInfoBean.getSSiteURL()); \o0z@Ntq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |}l@w +N3  
httpConnection.setRequestProperty("User-Agent","NetFox"); n+v!H O"2u  
X*_ SHt  
:8GlyN<E  
int responseCode=httpConnection.getResponseCode(); E=$7ieW  
if(responseCode>=400) 8[vl3C  
{ u!hqq^1  
processErrorCode(responseCode); Bidqf7v  
return -2; //-2 represent access is error 6(\q< fx  
} q] 2}UuM|U  
Sr4dY`V*:z  
Uyz;U34 oI  
String sHeader; _HSTiJVr  
8h55$j  
@hE7r-}]  
for(int i=1;;i++) kxcgOjrmI  
{ E!:.G+SEl  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #-l!`\@  
//Utility.log(in.readLine()); `HE>%=]b  
sHeader=httpConnection.getHeaderFieldKey(i); jB}_Slh1j  
if(sHeader!=null) :_W 0Af09  
{ gvow\9{|C  
if(sHeader.equals("Content-Length")) XHU<4l:kl  
{ R^n* o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8#[%?}tK  
break; AT2NC6{M  
} 8 /:X& &  
} J"m%q\'  
else {s9y@c*15.  
break; : OS mr  
} Dx9$H++6$X  
} | 7t=\  
catch(IOException e){e.printStackTrace ();} )Mm;9UA  
catch(Exception e){e.printStackTrace ();} sa\|"IkD2  
Enq6K1@%G  
Gnuo-8lb  
Utility.log(nFileLength); u* #-7   
GQEI f$  
A>rWGo.{E  
return nFileLength; EZgxSQaPH  
} Pf^Ly 97  
[wXwKr  
/6Jy'"+'0  
//保存下载信息(文件指针位置) 3G:NZ)p  
private void write_nPos() ,"v)vTt  
{ #dxJ#  
try{ !W+p<F1i  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6KBzlj0T+  
output.writeInt(nStartPos.length); N,'[:{GOY  
for(int i=0;i<nStartPos.length;i++) r7]?g~zb  
{ mjkw&2  
// output.writeLong(nPos); 3Vb=6-|  
output.writeLong(fileSplitterFetch.nStartPos); LOyCx/n  
output.writeLong(fileSplitterFetch.nEndPos); r1^m#!=B  
} 5bGjO&$l  
output.close(); J?|K#<%  
} yhJA;&}>  
catch(IOException e){e.printStackTrace ();} ebl)6C  
catch(Exception e){e.printStackTrace ();} q.u[g0h;  
} YU ]G5\UU  
UIm[DYMS  
(}/.4xE  
//读取保存的下载信息(文件指针位置) R-2FNl  
private void read_nPos() ,YAPCj  
{ d~P<M3#>  
try{ i_jax)m%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #NVF\  
int nCount = input.readInt(); =:v><  
nStartPos = new long[nCount]; VDb,$i.Z0  
nEndPos = new long[nCount]; 8VAYIxRv  
for(int i=0;i<nStartPos.length;i++) T9U2j-lA?  
{ E9Qd>o  
nStartPos = input.readLong(); D:RBq\8  
nEndPos = input.readLong(); u+I r:k  
} /w}B07.  
input.close(); D=q;+,Pc  
} O[5_ 9W 4  
catch(IOException e){e.printStackTrace ();} N c&i) qh  
catch(Exception e){e.printStackTrace ();} y . ivz  
} &?5{z\;1"  
6S&=OK^  
9wDBC~.  
private void processErrorCode(int nErrorCode) u]>>B>KOJ7  
{ :<WQ;q  
System.err.println("Error Code : " + nErrorCode); I!soV0V U]  
} :+?W  
yjM@/b  
08d_DCR  
//停止文件下载 "`$'tk[  
public void siteStop() 7/U<\(V!g  
{ s&QBFyKtJ  
bStop = true; &Curvc1fm  
for(int i=0;i<nStartPos.length;i++)  7KSGG1ts  
fileSplitterFetch.splitterStop(); n'&`9M['%d  
W2W2WyPk  
U_ ?elz\  
} 3A}nNHpN  
} #ejw@bd  
//负责部分文件的抓取 -'p@ lk  
**FileSplitterFetch.java 5M\=+5wB  
*/ 9,EaN{GM  
package NetFox; EV?47\ ~  
R6WgA@Z|r  
#@\NdW\  
import java.io.*; UmD-7Fd  
import java.net.*; :z0>H5  
K9qEi{[  
c!u}KVH  
public class FileSplitterFetch extends Thread { p,AD!~n`  
o"ah\"#el  
:@@A  
String sURL; //File URL @gqs4cg{f  
long nStartPos; //File Snippet Start Position 7U[L\1zS  
long nEndPos; //File Snippet End Position `2mbF ^-4  
int nThreadID; //Thread's ID R;TEtu7  
boolean bDownOver = false; //Downing is over EAd:`X,Y  
boolean bStop = false; //Stop identical /E4}d =5L  
FileAccessI fileAccessI = null; //File Access interface `TlUJ]d)  
sQw`U{JG  
F)5B[.ce  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException if!`Qid  
{ PSQ:'  
this.sURL = sURL; ,fG_'3wb  
this.nStartPos = nStart; .iN*V|n  
this.nEndPos = nEnd; }B '*8^S  
nThreadID = id; 'iISbOM  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C.B}Py+   
} \;:@=9`  
73z|'0.  
qD%&\ZT  
public void run() y" 6~9j  
{ 5<?c_l9X^  
while(nStartPos < nEndPos && !bStop) i`nw"8  
{ 9H%xZ(`vN  
8!%"/*P$  
n25tr'=  
try{ OUk5c$M(  
URL url = new URL(sURL); U>-#('  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fQ.>G+0 I>  
httpConnection.setRequestProperty("User-Agent","NetFox"); Cbg#Yz~/  
String sProperty = "bytes="+nStartPos+"-"; p+sPCF  
httpConnection.setRequestProperty("RANGE",sProperty); @$yYljP  
Utility.log(sProperty); hG;=ci3EE  
.QQI~p0:  
c2mt<DtWW  
InputStream input = httpConnection.getInputStream(); Bpo68%dx89  
//logResponseHead(httpConnection); |j}F$*SE[  
Y9L6W+=T  
N_k6UA9  
byte[] b = new byte[1024]; UR2)e{RXg  
int nRead; *#^1rKGWK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u\geD  
{ \ J:T]  
nStartPos += fileAccessI.write(b,0,nRead); ~d `4W<1a  
//if(nThreadID == 1) ;GT)sI   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Jb.u^3R@  
} Ib8{+j  
khIa9Nm  
ViT 5Jn7  
Utility.log("Thread " + nThreadID + " is over!"); >@Vr'kg+V  
bDownOver = true; [=F |^KL  
//nPos = fileAccessI.write (b,0,nRead); htrj3$q(4  
} 6SO7iFS  
catch(Exception e){e.printStackTrace ();} 6%INNIyAWa  
} }Q^a.`h  
} .) ;:K  
O:p649A  
dTQvz9C  
//打印回应的头信息 A":b_!sW  
public void logResponseHead(HttpURLConnection con) >D4Ez  
{ 6jo&i  
for(int i=1;;i++) B]F7t4Y!  
{ FF!g9>  
String header=con.getHeaderFieldKey(i); qML*Kwg  
if(header!=null) .%Q Ea_\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,4W((OQ^  
Utility.log(header+" : "+con.getHeaderField(header)); $[CA#AXE  
else 5@%-=87S  
break; 5m?$\h  
} j:KQIwc  
} gK\7^95  
ZKPkx~,U[  
S)|b%mVwR  
public void splitterStop() oz-I/g3go  
{ :=eUNH  
bStop = true; 8vW`E_n  
} 0%NI- Zyo  
VDY1F_Fk  
)_K@?rWS  
} !QS<;)N@  
'\\Cpc_g  
 PuCA @qY  
/* Ka\b_P&  
**FileAccess.java QXj(U&#rp  
*//文件访问(定位,写) }3y\cv0ct  
package NetFox; 4PM`hc  
import java.io.*; :?k=Yr  
lFY8^#@  
yLOLv6g~e  
public class FileAccessI implements Serializable{ " <a|Q,!  
&ru0i@?)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !T . @  
RandomAccessFile oSavedFile; }*R6p?L5  
long nPos; ye2Oh7  
z1s"C[W2T  
jloyJ@ck  
public FileAccessI() throws IOException |R/50axI  
{ dwMwd@*j  
this("",0); mP[u[|]  
} 8:fiO|~%  
9(j!#`O7&  
@ RBwT  
public FileAccessI(String sName,long nPos) throws IOException hz<J8'U  
{ e*s{/a?,  
oSavedFile = new RandomAccessFile(sName,"rw"); V1A3l{>L  
this.nPos = nPos; nTKfwIeg5  
oSavedFile.seek(nPos); NLY5L7  
} 3vU (4}@  
B4aZ3.&W  
3: Uik  
public synchronized int write(byte[] b,int nStart,int nLen) #KW:OFT  
{ sc60:IxgI  
int n = -1; =YIQ _,{u  
try{ E:k?*l  
oSavedFile.write(b,nStart,nLen); yk{alSF  
n = nLen; .vMi <U;  
} I&Y(]S,cU  
catch(IOException e) 3(5Y-.aK}^  
{ {eUfwPAa3  
e.printStackTrace (); 6< Z9p@6  
} e.V){}{V  
|e&Kg~~C  
EA.U>5Fq  
return n; &=bI3-  
} 2-84  
vNGvEJ`qn  
J~.kb k  
} G\%hT5^  
6! 'Xo:p  
W6Pg:Il7  
/* _8 J (;7  
**SiteInfoBean.java >kYyR.p.b  
*/ :xCobMs_/  
package NetFox; ny=iAZM>q  
F1>,^qyG6  
^ a:F*<D  
public class SiteInfoBean { kx[8#+P  
E<dN=#f6  
&&O=v]6,V  
private String sSiteURL; //Site's URL y1X.Mvc  
private String sFilePath; //Saved File's Path ~_%[j8o&l  
private String sFileName; //Saved File's Name pG&.Ye]j  
private int nSplitter; //Count of Splited Downloading File M .,|cx  
UlrY  
FhGbQJ?[3  
public SiteInfoBean() rNc>1}DDS  
{//nSplitter的缺省值为5 2lRZ/xaF%P  
//default value of nSplitter is 5 {y'k wU  
this("","","",5); d yd_dK/  
} 7(H/|2;-d8  
zYgLGwi{  
GcuZPIN%D  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >nX'RE|F  
{ EcU9Tm`h  
sSiteURL= sURL; wal }[F#  
sFilePath = sPath; Sgj6tH2M  
sFileName = sName; }_ E  
this.nSplitter = nSpiltter; ]7;;uhn`  
']Z8C)tK  
xpz Jt2S  
} P}gh-5x  
#LiC@>  
RMXP)[  
public String getSSiteURL() ^d,d<Uc  
{ 6]VTn-  
return sSiteURL; iYnt:C  
} x>cu<,e$d\  
k4v[2y`  
',f[y:v;  
public void setSSiteURL(String value) V6Y!0,w!a  
{ bGZy0.  
sSiteURL = value; L6T_&AiL$  
} sZc<h]L(g  
Y%3j >_\;  
D%zIm,bf  
public String getSFilePath() ",a fv{C  
{ PyYe>a;.  
return sFilePath; Wxjpe4  
} v!2`hq O  
"2mVW_k  
F>OYZOC]  
public void setSFilePath(String value) 7DD ot_qb  
{ kDsUKO p  
sFilePath = value; #]rw@c  
} Ab`Gb  
#ed]zI9O  
6*$N@>8&  
public String getSFileName() _wIAr  
{ fw<'ygd  
return sFileName; ^#+9v  
} /=%4gWtr  
>|<6s],v  
J{H475GqiT  
public void setSFileName(String value) /9sUp} *  
{ m35G;  
sFileName = value; ZP1EO Z  
} ws=y*7$y  
Mvux=Ws  
H_9~gi  
public int getNSplitter() tZJKB1#WbP  
{ sB $!X@  
return nSplitter; !*p lK6a  
} :H~r _>E  
!)GPI?{^5  
\>+gZc]an  
public void setNSplitter(int nCount) =Oy,SX  
{ bbz86]AhY  
nSplitter = nCount; #C|iW@  
} p?Y1^/   
} 3'8~H]<W  
7\.5G4dr%  
[* Lh4K  
/* S5j#&i  
**Utility.java + EM '-  
*/ 7Ev~yY;N  
package NetFox; d%WFgf}  
>6Q-e$GS@  
\o/oM,u  
public class Utility { PWTAy\  
d< y B ~Y  
fSj^/>  
public Utility() f.!cR3XgV  
{ 74Lq!e3hMF  
h-<+Pjc  
qu?D`29  
} t JJaIb6Xj  
5z0SjQ  
//线程睡眠 by- B).7  
public static void sleep(int nSecond) b(wiJ&t  
{ 'i}Q R~pe  
try{ x,n;GR  
Thread.sleep(nSecond); 8E D6C"6  
} wuPx6hCl  
catch(Exception e) \5Hfe;ny-~  
{ 'Ic$p>  
e.printStackTrace (); 'C(YUlT2?P  
} X4jtti  
} #U^@)g6  
X"yLo8y8$  
//日志 dD=dPi#  
public static void log(String sMsg) q?`bu:yS  
{ 0 ~VniF^  
System.err.println(sMsg); By" =]|Q  
} }_K7}] 1  
JD.WH|sZ5  
?>2k>~xlQ  
public static void log(int sMsg) hW(Mf  
{ m!g f!  
System.err.println(sMsg); lOql(ZH`w  
} !iMsTH<  
} 5@?P 8  
%|UCs8EFm  
(R{W Jjj  
/* )nQ.6  
**TestMethod.java cO' \s  
*/ fxjs"rD5  
package NetFox; %{axoGd  
WUKYwA/t  
ri6_u;Ch  
public class TestMethod { TeQpmhN  
geua8;  
^MuO;<<,.  
public TestMethod() H.*XoktC]  
{ ///xx/weblogic60b2_win.exe _E3*;  
try{ *U8Pjb1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Y7 = *-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4\3Z$%2^LZ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); G >bQlZG  
fileFetch.start(); LXr nAt  
} JW (.,Ztm  
catch(Exception e){e.printStackTrace ();} >osY?9  
+[ !K  
LyH{{+V  
} \It8+^d@  
F8f@^LVM/  
c5pF?kFaD  
public static void main(String[] args) &0~E+ 9b  
{ 8ex{N3  
new TestMethod(); Hr:WE+'  
} LNtBYdB`pK  
} iCnKQG  
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