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http断点续传简单实现(java)

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/* a,'Ncg  
**SiteFileFetch.java l^ 0_> R  
*/ ihiuSF<NaQ  
package NetFox; tpa^k  
import java.io.*; hB7pR"P  
import java.net.*; ^0~c 7`k`V  
!/6\m!e|1R  
TD{=L*{+  
public class SiteFileFetch extends Thread { 2:iYYRrg  
|ck ZyDA  
& &" 'dL  
SiteInfoBean siteInfoBean = null; //文件信息Bean Lo9G4Cu  
long[] nStartPos; //开始位置 z^rhgs?4  
long[] nEndPos; //结束位置 vXWsF\g  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 i}`_H^  
long nFileLength; //文件长度 j!x<QNNX  
boolean bFirst = true; //是否第一次取文件 J-tq8   
boolean bStop = false; //停止标志 p:JRQT"A  
File tmpFile; //文件下载的临时信息 R+{^@M&  
DataOutputStream output; //输出到文件的输出流 Y@]);MyL  
HkdN=q  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) #7]o6  
public SiteFileFetch(SiteInfoBean bean) throws IOException W(2+z5z  
{ qE0FgqRB  
siteInfoBean = bean; _,_8X7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X a"XB  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); lI4J=8O0  
if(tmpFile.exists ()) F?b'L JS  
{ "7kgez#Y  
bFirst = false; mQJ4;BJw  
read_nPos(); =t3vbV  
} N.0HfYf  
else M|UxE/  
{ YX ;n6~y  
nStartPos = new long[bean.getNSplitter()]; j|[(*i%7|  
nEndPos = new long[bean.getNSplitter()]; 4ZI!,lv*  
} tw'hh@7-Y  
?7yQ&p  
,u}<Ws8N  
OL=ET)Y  
} 8:HSPDU.  
9H h~ nR?  
X`yNR;>  
public void run() .!JMPf"QEI  
{ 3(!/["@7  
//获得文件长度 IXZ(]&we  
//分割文件 Z|ZBKcmg  
//实例FileSplitterFetch ~reQV6oQua  
//启动FileSplitterFetch线程 .3{[_iTM  
//等待子线程返回 / R_ u\?k(  
try{ ;TL(w7vK  
if(bFirst) 0)d?Y  
{ uxa=KM1H  
nFileLength = getFileSize(); Q[J [=  
if(nFileLength == -1) k42b:W5%  
{ Es'-wr\Hm  
System.err.println("File Length is not known!"); :be:-b%K  
}  Y*@|My`  
else if(nFileLength == -2) !8xKf*y  
{ zmf"I[)  
System.err.println("File is not access!");  3L%WVCB  
} ,IIZ Xl@  
else i8Fs0U4"  
{ T3PX gL)o  
for(int i=0;i<nStartPos.length;i++) ^|wT_k\  
{ 2GSgG.%SSM  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); la'e[t7  
} Z#-k.|}  
for(int i=0;i<nEndPos.length-1;i++) `n 3FT=  
{ \O kc5;kB2  
nEndPos = nStartPos[i+1]; S dIGU[fm  
} &/s~? Iq  
nEndPos[nEndPos.length-1] = nFileLength; hPa n  
} 0iYP  
} 1"}B]5!  
[{`)j  
Bul.RCP'  
//启动子线程 aXe{U}eow  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~|&="K4,:  
for(int i=0;i<nStartPos.length;i++) LeY+p]n~  
{ q*L ]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sN m,Fmuz:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), oW^k7 #<e}  
nStartPos,nEndPos,i); ~xS@]3n=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jCzGus!rM  
fileSplitterFetch.start(); pd d|n2q  
} I>{!U$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R N@^j  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  bRNK.[|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @ ]f3| >I  
nEndPos = " + nFileLength); u7HvdLql  
// fileSplitterFetch[nPos.length-1].start(); %yiD~&  
|/VL35b  
Uz 0W <u3v  
//等待子线程结束 tp Xa*6  
//int count = 0; NCa~#i:F8  
//是否结束while循环 A2y6UzLYD  
boolean breakWhile = false; 2B-.}OJ  
m}98bw  
rFo\+//  
while(!bStop) }sv!=^}BY3  
{ ^IBGYl5n  
write_nPos(); & g:%*>7P  
Utility.sleep(500); %y>+1hakkX  
breakWhile = true; Va7c#P?  
~LbS~_\C=  
O#Z/+\U  
for(int i=0;i<nStartPos.length;i++) gmY/STN   
{ a:A n=NA  
if(!fileSplitterFetch.bDownOver) +0J@y1  
{ |xh&p(  
breakWhile = false; Z==!C=SBv  
break; .U9 R> #  
} M#xQW`-`  
} )u;JwFstX  
if(breakWhile) .d~\Ysve  
break; )GVBE%!WEd  
Sk\n;mL:  
4qt+uNe!  
//count++; IZ*}idlkn/  
//if(count>4) 'w(y J  
// siteStop(); ;K_}A4K  
} JWWYVl VC  
f])M04<  
NPm;  
System.err.println("文件下载结束!"); 9JPEj-3`g  
} T"?Y5t`(  
catch(Exception e){e.printStackTrace ();} jv =EheD  
} !EOQhh  
.s2$al  
G}VDEC  
//获得文件长度 +3;Ody"59  
public long getFileSize() g:_hj_1Y M  
{ ;1 |x  
int nFileLength = -1; rfs(#  
try{  GP+2/D  
URL url = new URL(siteInfoBean.getSSiteURL()); TnNWO+ kg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y7z(&M@  
httpConnection.setRequestProperty("User-Agent","NetFox"); .k@^KY  
5;mRGY  
KY$k`f6?P  
int responseCode=httpConnection.getResponseCode(); i5"5&r7r  
if(responseCode>=400) BFWi(58q  
{ WuM C^  
processErrorCode(responseCode); r?p[3JJ;mG  
return -2; //-2 represent access is error EyY],W1 Y  
} _({@B`N}  
$W&:(&  
XE1$K_m  
String sHeader; vT c7an6fy  
H_w%'v&  
l4vTU=  
for(int i=1;;i++) ?^9BMQ+  
{ R4{-Qv#8 q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); E1  |<Pt  
//Utility.log(in.readLine()); XWUP=D~  
sHeader=httpConnection.getHeaderFieldKey(i); X*F_<0RC1  
if(sHeader!=null) cJDd0(tD!  
{ M-J<n>hl  
if(sHeader.equals("Content-Length")) LL(|$}yW  
{ ZyI$M3{J  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F2;:vTA>  
break; eY,O@'"8`  
} |0sPka/u16  
} #G#g|x*V  
else R,t$"bOd  
break; S2K#[mDG  
} %2"J:0j  
} |sIr?RL{C  
catch(IOException e){e.printStackTrace ();} 8#X_#  
catch(Exception e){e.printStackTrace ();} PLA#!$c7q  
rp's  
m\ S\3n  
Utility.log(nFileLength); O9s?h3  
icgJ;Q 5  
hJ*Ihwn|  
return nFileLength; ObG=>WPJa  
} j6S"UwJjp  
q0&$7GH4  
G:IP? z]  
//保存下载信息(文件指针位置) j1*f]va  
private void write_nPos() BT,b-= ;J-  
{ \X|sU:g  
try{ h|bT)!|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); w0w1PE-V=  
output.writeInt(nStartPos.length); h3!$r~T!a:  
for(int i=0;i<nStartPos.length;i++) PFrfd_s{>\  
{ ]$A(9Pn"  
// output.writeLong(nPos); };,/0Fu  
output.writeLong(fileSplitterFetch.nStartPos); v.&>Ih/L  
output.writeLong(fileSplitterFetch.nEndPos); GZ3 ]N  
} n~.*1. P  
output.close(); v2)g 1sXd  
} < zOi4v0  
catch(IOException e){e.printStackTrace ();} &nj&:?w  
catch(Exception e){e.printStackTrace ();} "m$3)7 $  
} Lrd[O v  
/<Ld'J  
i47j lyH  
//读取保存的下载信息(文件指针位置) ,"\@fwy{  
private void read_nPos() lv%9MW0 z  
{ -!e7L>w  
try{ s?rBE.g@}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ZnW@YC#9  
int nCount = input.readInt(); W*N$'%  
nStartPos = new long[nCount]; IH9.F  
nEndPos = new long[nCount]; By)u-)g9  
for(int i=0;i<nStartPos.length;i++) y<:<$22O  
{ z>m=h)9d~  
nStartPos = input.readLong(); P7.'kX9  
nEndPos = input.readLong(); ^oM|<";!?D  
} 9'[ N1Un.=  
input.close(); }ns-W3B'  
} (R!hjw~  
catch(IOException e){e.printStackTrace ();} ~" i0x  
catch(Exception e){e.printStackTrace ();} 1} %B%*N  
} T/1gI9 X  
rl08 R  
pkgjTXR2b  
private void processErrorCode(int nErrorCode) BlA[T%  
{ "IQ/LbOqm_  
System.err.println("Error Code : " + nErrorCode); 4_/?:$KO  
} #V,R >0"  
MGJ.,tK1  
k8AW6oO/i  
//停止文件下载 Wb}c=hZv  
public void siteStop() yQNV@T<o  
{ &;&ho+qD  
bStop = true; n>>Qn&ym  
for(int i=0;i<nStartPos.length;i++) k,yZ[n|`  
fileSplitterFetch.splitterStop(); ?9{~> 4@  
QXgE dsw  
ml`8HXK0  
} #OO>rm$  
} 'o_:^'c  
//负责部分文件的抓取 iB[~U3  
**FileSplitterFetch.java 0Hxmm@X2  
*/ jho**TQ P  
package NetFox; QX4ai3v  
42J {aJVH  
;r[@v347  
import java.io.*; HlvuW(,x=  
import java.net.*; W2FD+ wt  
_tTNG2  
gKYfQ+  
public class FileSplitterFetch extends Thread { "ZM4F?x  
E_e6^Sk5B(  
. mLK`c6  
String sURL; //File URL 4%nE*H%  
long nStartPos; //File Snippet Start Position q@t0NvNSu  
long nEndPos; //File Snippet End Position Zwz&rIQpT  
int nThreadID; //Thread's ID ",7Q   
boolean bDownOver = false; //Downing is over *!s;"U  
boolean bStop = false; //Stop identical #|&Sc_#4)  
FileAccessI fileAccessI = null; //File Access interface 1i[FY?6`dh  
nw>8GivO  
#9-P%%kQ  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (0YZZ93  
{ /='. 4 v  
this.sURL = sURL; d)4 m6  
this.nStartPos = nStart; CHrFM@CM  
this.nEndPos = nEnd; p2Zo  
nThreadID = id; 1cS}J:0P  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8>,jpAN}r  
} S"wR%\NIp  
7(5xL T$  
5[0 O'%$  
public void run() ho##Z*O  
{ =  C4  
while(nStartPos < nEndPos && !bStop) EkgE_8  
{ r\qj!   
W`\R%>$H  
EQ'V{PIfj  
try{ ?7<JQh)"e  
URL url = new URL(sURL); Zjbc3 M5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a}%#*J)!  
httpConnection.setRequestProperty("User-Agent","NetFox"); =|3fs7  
String sProperty = "bytes="+nStartPos+"-"; *%{gYpn  
httpConnection.setRequestProperty("RANGE",sProperty); <B9C*M"4%  
Utility.log(sProperty); *s9C!w YMZ  
kY*rb_2j  
&|f@$ff  
InputStream input = httpConnection.getInputStream(); H,Z;=N_  
//logResponseHead(httpConnection); rE}%KsZ  
.C8PitS  
sCR67/  
byte[] b = new byte[1024]; =c/wplv*  
int nRead; uV!^,,~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q09[[  
{ +L7n<U3  
nStartPos += fileAccessI.write(b,0,nRead); ma"3qGy  
//if(nThreadID == 1) ]IoUwgpI)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VeW>[08  
} ek#O3Oz  
S H!  
anXc|  
Utility.log("Thread " + nThreadID + " is over!"); 0g0i4IV  
bDownOver = true; ;W>k@L  
//nPos = fileAccessI.write (b,0,nRead); l c+g&f  
} 9 FB19  
catch(Exception e){e.printStackTrace ();} =EHUR'  
} zuUW|r  
} !o:f$6EA~C  
D#3\y*-y?  
rg^'S1x|  
//打印回应的头信息 XUz3*rfs  
public void logResponseHead(HttpURLConnection con) :A/d to  
{ 5H*\t 7  
for(int i=1;;i++) TWA-.>c  
{ Z'"tB/=W  
String header=con.getHeaderFieldKey(i); ILGMMA_2  
if(header!=null) a(l29>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _d5QbTe  
Utility.log(header+" : "+con.getHeaderField(header)); "wNJ  
else 9I}-[|`u  
break; Wf|Q$MHos  
} gIjh:_ Pz  
} 7@D@ucL  
`$ 6rz  
tfj:@Z5&$C  
public void splitterStop() Qk:Y2mL  
{ 8fl`r~bqZ  
bStop = true; wne,e's}   
} LDPUD'  
`aciXlqIF  
Lm%:K]X  
} Tf'hc]`vS  
G3Z)Z) N  
%J+E/  
/* KrQ1GepJ  
**FileAccess.java  # 1OOU  
*//文件访问(定位,写) e)d`pQ6  
package NetFox; <g$~1fa  
import java.io.*; !2ZF(@C /  
;U-jO &  
<0Xf9a8>  
public class FileAccessI implements Serializable{ ? m DI#~)  
E|iQc8gr&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 F(>Np2oi6  
RandomAccessFile oSavedFile; .+$ Q<L  
long nPos; <3LbN FP  
32&;`]C  
M/b Sud?@%  
public FileAccessI() throws IOException .(K)?r-g5  
{ ~E17L]ete  
this("",0); 3LOdjT J  
} e"|efE  
KVclhT<F  
VK m&iidU  
public FileAccessI(String sName,long nPos) throws IOException '=b/6@&  
{ {*G9|#[/@  
oSavedFile = new RandomAccessFile(sName,"rw"); ].-1v5  
this.nPos = nPos; h`^jyoF"(  
oSavedFile.seek(nPos); dYJ(!V&  
} y [}.yyye  
UtoT  
os=e|vkB*  
public synchronized int write(byte[] b,int nStart,int nLen) u_oaebOrpP  
{ k\5c|Wq|g  
int n = -1; ~%&LTX0s|  
try{ 9jM}~XvV  
oSavedFile.write(b,nStart,nLen); H\ F :95  
n = nLen; Lt64JH^lz  
} <:+x+4ru  
catch(IOException e) 5?{ r  
{ +^60T$  
e.printStackTrace (); TM%| '^)  
} ]cHgleHQ  
)_YX DU  
9X}10u:  
return n; ]_f_w 9]  
} T(id^ w  
Q /U2^  
$V -~Bu-  
} gb[5&> (#  
M?1Y,5  
=^M/{51j  
/* 6]K_m(F  
**SiteInfoBean.java %O|iE M  
*/ Ag-(5:  
package NetFox; (KjoSN( K  
+}Dw3;W}m  
xQ7l~O b  
public class SiteInfoBean { rBQ_iB_  
<FV1Wz  
G#ZH.24Y  
private String sSiteURL; //Site's URL <sb~ ^B  
private String sFilePath; //Saved File's Path }bb;~  
private String sFileName; //Saved File's Name {'7B6  
private int nSplitter; //Count of Splited Downloading File - YEZ]:"  
G/)O@Ugp  
6AAz  
public SiteInfoBean() BX`{73sw  
{//nSplitter的缺省值为5 D+rxT: d  
//default value of nSplitter is 5 bQg c8/  
this("","","",5); t% d Z-Ym  
} 0yk]o5a++  
rD*jp6Cl  
cN/6SGHK  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) W=~~5jFX  
{ ;AG8C#_  
sSiteURL= sURL; .]8ZwAs=&  
sFilePath = sPath; d[iQ` YW5  
sFileName = sName; c[0}AG J  
this.nSplitter = nSpiltter; wON!MhA;  
/CrSu  
uy>q7C  
} lU8l}Ndz"  
}7b%HTF=  
(~p< P+  
public String getSSiteURL() ; 5*&xz  
{ )3cAQ'w  
return sSiteURL; j`{?OYD  
} Y`~Ut:fZ  
'g}!  
<$D`Z-6  
public void setSSiteURL(String value) sA+ }TNhq  
{ /:cd\A}  
sSiteURL = value; g@d*\ P)  
} ]%;:7?5l  
9)l$ aBa  
#|uCgdi  
public String getSFilePath() )HEa<P^kJl  
{ [:7'?$  
return sFilePath; #]\Uk,mhZB  
} ^ gdaa>L  
)*u8/U  
`}p0VmD{NE  
public void setSFilePath(String value)  on4HKeO  
{ iDpSj!x/_  
sFilePath = value; mVj9, q0  
} * ` JYC  
z0 d.J1VW  
/4yo`  
public String getSFileName() sU=H&D99  
{ D(~U6SR  
return sFileName; D, k6$`  
} f[]dfLS"W  
H%[eV8  
C"y(5U)d  
public void setSFileName(String value) dn& s*  
{  {y)=eX9  
sFileName = value;  CT&|QH{  
} 5tl< 3g `  
0 j^Kgx  
B`EJb71^Xy  
public int getNSplitter() l5~os>  
{ d9k0F OR1  
return nSplitter; R|'ybW'Y  
} AzPu)  
QFA8N  
rjK%t|aV^  
public void setNSplitter(int nCount) hqD*z6aH  
{ @ JGP,445  
nSplitter = nCount; 49eD1h3'X[  
} |44Ploz2b  
} M$ wC=b  
R7%#U`Q^A  
91/Q9xY  
/* \UA[  
**Utility.java L7l FtX+b  
*/ ]>!K3kB  
package NetFox; Z*F3G#A  
11NQR[  
9p]QM)M  
public class Utility { HVRZ[Y<^  
s9 mx  
p#-Z4-`  
public Utility() rm7ANMB:  
{ [z:!j$K  
&0d# Y]D4`  
9gW|}&-  
} e+EQ]<M  
 8$=n j  
//线程睡眠 ?d*z8w  
public static void sleep(int nSecond) @@f"%2ZR[  
{ GC-5X`Sq  
try{ .e#w)K  
Thread.sleep(nSecond); x[p|G5  
} KR} ?H#%  
catch(Exception e) 9+|$$)  
{ KM, \  
e.printStackTrace (); }PlRx6r@  
} jRa43ck  
} ~g91Pr   
#<fRE"v:Q  
//日志 ZtNN<7  
public static void log(String sMsg) (g]!J_Z"  
{ 8\^R~K`sY  
System.err.println(sMsg); Xg6Jh``  
} 9X6h  
Ov@gh kr  
}CSDV9).S  
public static void log(int sMsg)  1~gnc|?  
{ l$KA)xbI  
System.err.println(sMsg); t 9lPb_70  
} FaAC&F@u  
} MpT8" /.]A  
Q0sI(V#  
hgG9m[?K  
/* r `=I  
**TestMethod.java '@v\{ l  
*/ SO/c}vnBB  
package NetFox; AYBns]!  
[jQp~&nY  
&u."A3(  
public class TestMethod { CO/]wS  
`v!urE/gg%  
%@b0[ZC  
public TestMethod() h,:m~0gmj  
{ ///xx/weblogic60b2_win.exe ]h`&&Bqt  
try{ LE Nq_@$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); bIDj[-CDG  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); K-)] 1BG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (XTG8W sN  
fileFetch.start(); k=$TGqQY?  
} ;nfdGB  
catch(Exception e){e.printStackTrace ();} bW427B0  
Wu/]MBM  
BKCiIfkZ  
} 5Pc;5 o0C  
8Al{+gx@?  
v4TQX<0s  
public static void main(String[] args) -m zIT4  
{ u {cW:  
new TestMethod(); QT5TE: D  
} a=_g*OK}D  
} o'aEY<mZ7  
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