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http断点续传简单实现(java)

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/* $, fX:x  
**SiteFileFetch.java eQvg7aO;  
*/ d8x;~RA  
package NetFox; ?@ $r  
import java.io.*; e64^ChCoV  
import java.net.*; Lq!>kT<]!  
;P&OX5~V  
N$:8 ,9.z  
public class SiteFileFetch extends Thread { w"&n?L  
 1ZB"EQ  
FN) $0  
SiteInfoBean siteInfoBean = null; //文件信息Bean b*Q&CL  
long[] nStartPos; //开始位置 !_Z&a  
long[] nEndPos; //结束位置 R_S.tT!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?#Q #u|~  
long nFileLength; //文件长度 lCHO;7YHX  
boolean bFirst = true; //是否第一次取文件 2T[9f;jM'  
boolean bStop = false; //停止标志 $a ` G  
File tmpFile; //文件下载的临时信息 <yg F(  
DataOutputStream output; //输出到文件的输出流 &XUiKnNW  
tIS<U(N ;  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) >~+ELVB&  
public SiteFileFetch(SiteInfoBean bean) throws IOException L\z~uo3:  
{ K )k<Rh[<  
siteInfoBean = bean; VTHH&$ZNq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wJY'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n>U5R_T  
if(tmpFile.exists ()) 6/dI6C!  
{ 4]}'Hln*U  
bFirst = false; IRqy%@)  
read_nPos(); 42ivT_H  
} iM 3V=&)  
else i8HTzv"J  
{ 8Kk(8a&v  
nStartPos = new long[bean.getNSplitter()]; DrK{}uM  
nEndPos = new long[bean.getNSplitter()]; 8BNi1Qn$  
} ;@E$}*3[>V  
LvYB7<zk>  
-!]ZMi9  
?p8_AL'RS  
} >t_6B~x9  
5rZ  
F`]2O:[  
public void run() WQO) =n  
{ GF=g<H M  
//获得文件长度 /fV;^=:8c  
//分割文件 q?/a~a  
//实例FileSplitterFetch "|KP'<8%  
//启动FileSplitterFetch线程 r1RM  
//等待子线程返回 5bpEYW+  
try{ R<N ]B  
if(bFirst) fZA4q0  
{ }txX; "/  
nFileLength = getFileSize(); Aj]V`B:65  
if(nFileLength == -1) hp L;bM'  
{ ZLAy- 9^Y  
System.err.println("File Length is not known!"); R@k&SlL'`  
} "kgdbAZ  
else if(nFileLength == -2) Rr|VD@%  
{ i@M [>~  
System.err.println("File is not access!"); Y,zxbXZv'5  
} q{;:SgZ  
else c=.(!qdH  
{ l0A&9g*l2  
for(int i=0;i<nStartPos.length;i++) mUF,@>o  
{ p0<\G  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <B8!.|19  
} 0b(N^$js'  
for(int i=0;i<nEndPos.length-1;i++) fkNbS  
{ e'D&8z_;  
nEndPos = nStartPos[i+1]; I"7u2"@-8j  
} O/(xj2~$ J  
nEndPos[nEndPos.length-1] = nFileLength; vTw>JNVI  
} GYUn6P  
} yd`mG{Z  
'u<juFr  
RQu(Wu|m.  
//启动子线程 $[=%R`~w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,]c 1A$Sr0  
for(int i=0;i<nStartPos.length;i++) 3 xp)a%=7  
{ !H>R%g#28_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M?uC%x+S$_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xAMW-eF?d  
nStartPos,nEndPos,i); AX/m25x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w!clI8v/  
fileSplitterFetch.start(); Z Sd4z:/  
} Pdt vU-(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), , ^f+^^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $aXer:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", U2s /2 [.  
nEndPos = " + nFileLength); G,Azm }+  
// fileSplitterFetch[nPos.length-1].start(); I,@6J(9  
>> fH{/l  
*N'p~LJ  
//等待子线程结束 "d5n \@[t  
//int count = 0; OMg<V  
//是否结束while循环 ?zHPJLv|Y  
boolean breakWhile = false; L<{i ,'M  
ThbGQ"/  
zi*R`;_`,  
while(!bStop) pOG1jI5<{8  
{ 2'MZ s]??w  
write_nPos(); m#Z# .j_2  
Utility.sleep(500); Is?La  
breakWhile = true; 9ahWIO %  
j+v=Ul|l  
[!]2 djc  
for(int i=0;i<nStartPos.length;i++) L"*/:$EJL.  
{ O~K>4 ax  
if(!fileSplitterFetch.bDownOver) gi _5?$  
{ ` 3K)GA  
breakWhile = false; O2dW6bt  
break; )*x6 FfTUd  
} u-G+ j)  
} Jd^,]  
if(breakWhile) uT7B#b7  
break; gz#i.-  
q2:6QM&  
eHNyNVz  
//count++; \%N!5>cZ{  
//if(count>4) 6-B|Y3)B  
// siteStop(); ):_\;.L  
} Ur=(.%@  
R)ITy!z  
b-Q>({=i  
System.err.println("文件下载结束!"); !.(P~j][  
} T&o(N3lW  
catch(Exception e){e.printStackTrace ();} VYImI>.t{  
} Ob`d  
!AfHk|  
s?,Ek  
//获得文件长度 Opc ZU{4 b  
public long getFileSize() JB]q   
{ ia E^a^*  
int nFileLength = -1; H{?vbqQ  
try{ "J8vjr1/  
URL url = new URL(siteInfoBean.getSSiteURL()); 0Bi.6r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  e5*hE  
httpConnection.setRequestProperty("User-Agent","NetFox"); rJbf_]^  
=\wxsL  
>!bJslWA  
int responseCode=httpConnection.getResponseCode(); @{tz:f  
if(responseCode>=400) 8~z~_TD6m@  
{ 3! oi+_  
processErrorCode(responseCode); dD|OSB7 I7  
return -2; //-2 represent access is error NmJWU:W_@  
} hD*SpVI U  
YhE+W  
LKOwxF#TKT  
String sHeader; P0j8- I  
p(`6hWx  
(w/T-*  
for(int i=1;;i++) B s#hr3h-  
{ .|b$NM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K<ft2anY5  
//Utility.log(in.readLine()); +kO!Xc%P&  
sHeader=httpConnection.getHeaderFieldKey(i); (UvM@]B  
if(sHeader!=null) q[W 0 N >  
{ Q&=w_Wc  
if(sHeader.equals("Content-Length")) jun_QiU:2  
{ _Wq  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); cacr=iX  
break; %'7lbpy,f  
} J1sv[$9  
} hp7|m0.JW  
else ?6un4EVL{  
break; UK O[r;  
} ^!ZC?h!rG  
} YS@ypzc/  
catch(IOException e){e.printStackTrace ();} J1I ;Jgql(  
catch(Exception e){e.printStackTrace ();} ERE)A-8  
^N;.cY  
TNY&asQo  
Utility.log(nFileLength);  s ;oQS5Y  
1o;J,dYu  
xLWw YK  
return nFileLength; $oU*9}}Rn  
} b TM{l.Aq3  
%GA"GYL9'  
evAMJ=  
//保存下载信息(文件指针位置) -Rd/G x  
private void write_nPos() #_J@-f7^  
{ pg.ri64H<  
try{ UT=tT )4b  
output = new DataOutputStream(new FileOutputStream(tmpFile)); F{Jw ^\  
output.writeInt(nStartPos.length); N OiN^::m  
for(int i=0;i<nStartPos.length;i++) ,p2s:&"  
{ !K}~/9Z=m  
// output.writeLong(nPos); (ehK?6[  
output.writeLong(fileSplitterFetch.nStartPos); `W:%mJd9  
output.writeLong(fileSplitterFetch.nEndPos); ?:8ido#-  
} +*T7@1  
output.close(); Dhw(#{N  
} ;q:zT\A  
catch(IOException e){e.printStackTrace ();} $M lW4&a|  
catch(Exception e){e.printStackTrace ();} Ax?y  
} O%(fx!c`  
kabnVVn~  
uK$9Ll{lk  
//读取保存的下载信息(文件指针位置) q[`]D7W "  
private void read_nPos() !tMuuK?IL=  
{ BJB^m|b)  
try{ D2!X?"[ P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); UAFwi%@!-q  
int nCount = input.readInt(); x:>wUhzZ  
nStartPos = new long[nCount]; E^lvbLh'  
nEndPos = new long[nCount]; Wm"4Ae:B  
for(int i=0;i<nStartPos.length;i++) + SFVv_n  
{ gp^ 5#  
nStartPos = input.readLong(); d + /&?3  
nEndPos = input.readLong(); %?uc><&?e  
} ;WM"cJo9  
input.close(); {VvqO7A  
} cU@SIJ)  
catch(IOException e){e.printStackTrace ();} [}/LD3  
catch(Exception e){e.printStackTrace ();} u7\J\r4,+  
} i2YuOV!  
Q}K#'Og  
{QZUDPPR  
private void processErrorCode(int nErrorCode) *4xat:@{{  
{ SHbtWq}T  
System.err.println("Error Code : " + nErrorCode); ~\.w^*$#Y  
} ^3{TZ=_;|  
OK6] e3UO  
;04Ldb1{|3  
//停止文件下载 e8]\U/  
public void siteStop() 8V)^R(\;  
{ r>"   
bStop = true; RGg(%.  
for(int i=0;i<nStartPos.length;i++) n'01Hh`0  
fileSplitterFetch.splitterStop(); oA7;.:3  
V7[zAq  
"@d[h,TM  
} wsN?[=l{s  
} x&9hI  
//负责部分文件的抓取 C\nhqkn  
**FileSplitterFetch.java fX.>9H[w@~  
*/ 4%}*&nsI-Z  
package NetFox; ZF|+W?0&%  
>`wV1^M6?  
lR[qqFR  
import java.io.*; 'u_t<F ]b  
import java.net.*; Ikiib WQL+  
T/xp?Vq6/  
2 :mn</z  
public class FileSplitterFetch extends Thread { I8<,U!$  
\B 0ywN?  
2Sp=rI  
String sURL; //File URL CkD#/  
long nStartPos; //File Snippet Start Position ;SaX;!`39+  
long nEndPos; //File Snippet End Position C;`XlQG `  
int nThreadID; //Thread's ID Bj}^\Pc;}  
boolean bDownOver = false; //Downing is over {>,V\J0p  
boolean bStop = false; //Stop identical !V\Q<So<  
FileAccessI fileAccessI = null; //File Access interface \XM^oE#G  
ZAUQJS 91E  
&S]@Ot<z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException F;[T#N:~  
{ w@ c87;c  
this.sURL = sURL; |- rI@2`  
this.nStartPos = nStart; rEv*)W  
this.nEndPos = nEnd; r8&^>4  
nThreadID = id; OD 3f.fT  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E3l> 3  
} :.d:9Z|_  
\&3"<6xA  
^;maotHn  
public void run() J.dLPKU;-  
{ t|!j2<e  
while(nStartPos < nEndPos && !bStop) E)7F\w  
{ S:q3QgU=X  
CQr<N w  
.E&z$N  
try{ FwY&/\J7V  
URL url = new URL(sURL); f<*Js)k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]M[#.EX  
httpConnection.setRequestProperty("User-Agent","NetFox"); I}t3 p|z  
String sProperty = "bytes="+nStartPos+"-"; A"l?:?rtw]  
httpConnection.setRequestProperty("RANGE",sProperty); r"a5(Q;n  
Utility.log(sProperty); dT$M y`>  
qY$qaM^=  
Fxqp-}:  
InputStream input = httpConnection.getInputStream(); n?ctLbg  
//logResponseHead(httpConnection); ~$f;U  
E55t*^`  
UH>F|3"d  
byte[] b = new byte[1024]; D?,#aB"  
int nRead; M$d%p6Cv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xD /9F18  
{ RZ7( J  
nStartPos += fileAccessI.write(b,0,nRead); .tmiQ.  
//if(nThreadID == 1) N!x =eC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "zY](P  
} ND,Kldji  
zBp{K@U[|M  
{}m PEd b  
Utility.log("Thread " + nThreadID + " is over!"); nG, U>)  
bDownOver = true; >Clh] ;K  
//nPos = fileAccessI.write (b,0,nRead); +|{RE.DL  
} f%)zg(YlO  
catch(Exception e){e.printStackTrace ();} $GQ-(/  
} ;k86"W  
} za9)Q=6FD  
rVa?JvDO=  
6ubL1K  
//打印回应的头信息 fr}Eaa-{^  
public void logResponseHead(HttpURLConnection con) X_G| hx  
{ >'5_Y]h4m|  
for(int i=1;;i++) :BukUket1e  
{ he-Ji  
String header=con.getHeaderFieldKey(i); JwRF(1_sM  
if(header!=null) eo!zW  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); GK}'R=   
Utility.log(header+" : "+con.getHeaderField(header)); 9F- )r'  
else 'snn~{hG  
break; 5,;`$'?a%  
} G"59cv8z4R  
} a7/-wk  
\WrFqm#  
lvpc*d|K  
public void splitterStop() X$\i{p9jw  
{ KZ e)K_1[  
bStop = true; `L5~mb;7*  
} J3b4cxm  
@[?!s%*2  
nGf);U#K  
} &Q=ZwC7#  
omf  Rs  
]:$ O{y  
/* L~/qGDXC?  
**FileAccess.java qxMnp}O  
*//文件访问(定位,写) >x@P|\  
package NetFox; c<BO gNr  
import java.io.*; XC3Kh^  
'[(nmx'yVJ  
}o,z!_^PLQ  
public class FileAccessI implements Serializable{ +P`(Rf"luu  
\#x}q'BC4  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 E%TpJl'U  
RandomAccessFile oSavedFile; 9>#:/g/  
long nPos; x/MZ(A%D  
^D_/=4rz8  
6V+ qnUk  
public FileAccessI() throws IOException &>jAe_{",  
{ ]43bere  
this("",0); (5Tvsw`  
} V' 2EPYB  
+1Ph<zq"  
l  n }}5Q  
public FileAccessI(String sName,long nPos) throws IOException "%QD{z_L  
{ m:O(+Fl  
oSavedFile = new RandomAccessFile(sName,"rw"); y8bM<e2 U  
this.nPos = nPos; OAZ#|U   
oSavedFile.seek(nPos); Pe~`16f  
} k)FmDX  
&?p:3%;Dr  
|"$uRV=qm  
public synchronized int write(byte[] b,int nStart,int nLen) 0-3rQ~u  
{ ?vGf fMm  
int n = -1; 5lJ )(|_  
try{ ?68uS;  
oSavedFile.write(b,nStart,nLen); :Ze+%d=  
n = nLen; :y,v&Kk#T  
} d( *fy}  
catch(IOException e) W {.78Zi9K  
{ td-3h,\\  
e.printStackTrace (); ? {F{;r  
} -,":5V26  
]y)Q!J )Q  
baoD(0d  
return n; N 6O8Wn  
} dd7 =)XT+  
y9;#1:ic  
qJT0Y/l:(  
} ]&i+!$N_  
[{<dbW\ 9  
6a>H|"P NE  
/* E)t  
**SiteInfoBean.java 4R) |->"  
*/ 6j8 <Q 2  
package NetFox; jUjr6b"  
!m{2WW-  
9-bG<`v\E  
public class SiteInfoBean { Lg`Jp&Kg  
, Ut Hc]  
cf[vf!vi  
private String sSiteURL; //Site's URL r<L#q)]  
private String sFilePath; //Saved File's Path 3@O0^v-  
private String sFileName; //Saved File's Name ?Zyok]s  
private int nSplitter; //Count of Splited Downloading File gw3NS8 A+  
JK~ m(oQ  
P-JfV7(O8  
public SiteInfoBean() $ A-b vL  
{//nSplitter的缺省值为5 F}rPY:  
//default value of nSplitter is 5 HrqF![_  
this("","","",5); ._p""'Sa  
} \w )?SVp  
76#.F  
*"G8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {%']w  
{ d\XRUO[  
sSiteURL= sURL; i&@,5/'-_O  
sFilePath = sPath; ^ZQCIS-R  
sFileName = sName; LE c8NQs  
this.nSplitter = nSpiltter; DQ=N1pft2v  
A@$fb}CF  
s5Fr)q// !  
} FyEDt@J  
%N~C vN@T  
VVrwOo CN  
public String getSSiteURL() iM64,wnA  
{ .:;fAJPf  
return sSiteURL; `.k5v7!o  
} 5&4F,v[zp  
yCM{M  
<~%t$:  
public void setSSiteURL(String value) zw:/!MS  
{ \kwe51MQ  
sSiteURL = value; +|nsu4t,<  
} gB CC  
{>.>7{7  
S+*cbA{J|  
public String getSFilePath() ;x>;jS.t  
{ T=? bdIl  
return sFilePath; .{N\<01  
} )Ul&1UYA  
ye r> x  
.g-3e"@  
public void setSFilePath(String value) uU+s!C9r  
{ O=O(3Pf>  
sFilePath = value; -"Gl 4)  
} L/k40cEI^z  
tmxPO e  
BpXEK.Xw  
public String getSFileName() HRRngk#lV  
{ f0F#Yi{fw  
return sFileName; VA]ZR+m  
} _XN~@5elrC  
F|]rA*2u  
9c5!\m1  
public void setSFileName(String value) >1XL;)IL>  
{ dx359  
sFileName = value; x9*ys;~w  
}  g@(30{  
CB@B.)E  
|,fh)vO  
public int getNSplitter() x[m'FsR4  
{ T^.{9F]*S  
return nSplitter; $wXih#7  
} rAatJc"0  
S 1>Z6  
WRMz]|+}4  
public void setNSplitter(int nCount) WB"$u2{|i  
{ j];1"50?  
nSplitter = nCount; |\p5mh  
} anitqy#E  
} xXa#J)'  
#HcI4j:s!  
)9pBu B  
/* Y_shy6" KH  
**Utility.java }I<N^j=/pO  
*/ H5^Y->  
package NetFox; & 3I7]Wm  
sRil>6QR  
i0&) N,5_  
public class Utility { 6(5c7R#  
}` @?X"r  
ks^|>  
public Utility() 0- Yeu5A  
{ $pBr &,  
3V!x?H$  
>huqt|S*9  
} { ;' :h  
pqd4iR Wv  
//线程睡眠 1'OD3~[R  
public static void sleep(int nSecond) B$EK_@M  
{ IHfSkFz`j  
try{ )ldUayJ  
Thread.sleep(nSecond); r?XDvU  
} C_89YFn+  
catch(Exception e) 8ok7|DJ  
{ z5I^0'  
e.printStackTrace (); Lj-{t% }  
} $ACe\R/%  
} 8|_K  
dTgM"k  
//日志 6 cr^<]v!  
public static void log(String sMsg) Uc>LFX& -B  
{ o[H\{a>  
System.err.println(sMsg); |<2JQ[]  
} iqlVlm>E  
vD"_X"v  
nvwDx*[qN  
public static void log(int sMsg) J4&XPr9  
{ 8Y]}Gb!  
System.err.println(sMsg); BfEx'C  
} k4* ! Q_A  
} n+S&!PB  
%`N&ti  
iPJ9Gh7  
/* ^$?7H>=_ha  
**TestMethod.java >R) F}  
*/ gtl;P_  
package NetFox; aSxG|OkKy  
Ny[s+2?  
(#lm#?<)  
public class TestMethod { fLc!Sn.Y  
V4qZc0<,H  
T=O l`?5  
public TestMethod() 2@OBeR  
{ ///xx/weblogic60b2_win.exe `,Q<YT ~  
try{ ] +sSg=N7i  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >dcqPNDg1^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1_XO3P\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); nN!vgn j  
fileFetch.start(); la1D2 lM  
} MH2OqiCI  
catch(Exception e){e.printStackTrace ();} <m:4g ,6  
{m>~`   
sL;z"N@PK  
} SIJ# ?0,  
V&$  J;  
t P At?  
public static void main(String[] args) Fj36K6!#?  
{ 'XG:1Bpm  
new TestMethod(); h7)VJY  
} 6Eij>{v  
} `mQP{od?"?  
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