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http断点续传简单实现(java)

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/* c~+l|r=u?  
**SiteFileFetch.java U GJ# "9  
*/ q#N8IUN}4  
package NetFox; ro4 XA1  
import java.io.*; KBo/GBD]|  
import java.net.*; nr<&j#!L  
3pKr {U92  
G>0S( M)  
public class SiteFileFetch extends Thread { u9"1%  
KCkA4`IeM  
v-@xO&<  
SiteInfoBean siteInfoBean = null; //文件信息Bean u%=M4|7  
long[] nStartPos; //开始位置 G#;$;  
long[] nEndPos; //结束位置 ZO $}m?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 t`X-jr)g  
long nFileLength; //文件长度 {'#^  
boolean bFirst = true; //是否第一次取文件 +kKfx!  
boolean bStop = false; //停止标志 <t0o{}^P*  
File tmpFile; //文件下载的临时信息 OQON~&~  
DataOutputStream output; //输出到文件的输出流 85 tQHm6j  
7$7Y)&\5 w  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) [/ E_v gZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException wDV%.Cc  
{ Yg6 f  
siteInfoBean = bean; agFWye  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); D'Gmua]I  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); L.z`>1  
if(tmpFile.exists ()) NK+iLXC  
{ j6KGri  
bFirst = false; $z~sN  
read_nPos(); cO"7wgg  
} ;Qc_Tf=,  
else NQ@."8  
{ T)ra>r<#  
nStartPos = new long[bean.getNSplitter()]; J34lu{'if  
nEndPos = new long[bean.getNSplitter()]; vH+QI  
} 6 ztM(2[  
J!o[/`4ib  
)MZQ\8,)]  
MNKB4C8 >  
} KS/1ux4x  
wU#79:h  
PXk+Vi,%k  
public void run() "1H?1"w~  
{ }w&+ H28.#  
//获得文件长度 t YmR<^  
//分割文件 37@_"  
//实例FileSplitterFetch Q2)z1'Wv  
//启动FileSplitterFetch线程 =M'y& iz-  
//等待子线程返回 $!<J_ d*  
try{ A({8p  
if(bFirst) mzz77i  
{ Y,kTk  
nFileLength = getFileSize(); 8qfg=mu+ %  
if(nFileLength == -1) zUqt^_  
{ t/K<fy 6  
System.err.println("File Length is not known!"); eM*@zo<-  
} j|&?BBa9  
else if(nFileLength == -2) shwKB 5  
{ H1'`* }V  
System.err.println("File is not access!"); 99}n %(V  
} n; 0bVVMV  
else a(Bo.T<2@  
{ ;Bo{.916  
for(int i=0;i<nStartPos.length;i++) I% 43rdoPe  
{ tdn[]|=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^<R*7mB*  
} !+4}x;!8  
for(int i=0;i<nEndPos.length-1;i++) y8Bi5Ae,+1  
{ \$2E  
nEndPos = nStartPos[i+1]; Kv[,!P"Y  
} gg(^:`+  
nEndPos[nEndPos.length-1] = nFileLength; *BYSfcX6  
} /s>ZT8vaAs  
} Eoug/we  
;K[`o/#4"  
MX 2UYZ&  
//启动子线程 'Lft\.C  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; EnJAHgRV;e  
for(int i=0;i<nStartPos.length;i++) jZcjiOX  
{ g_}r)CgG|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `Njv#K} U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !Jw   
nStartPos,nEndPos,i); Yz0ruhEMk  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !Re/W ykY  
fileSplitterFetch.start(); ,>n 4 `A  
} N0h"EV[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q#-szZQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \. A~>=:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R/M:~h~F!  
nEndPos = " + nFileLength); ur-&- G^  
// fileSplitterFetch[nPos.length-1].start(); BlS0I%SN  
@4 m_\]Wy  
AA9OElCa  
//等待子线程结束 : 2?J#/o  
//int count = 0; gOZ$rv^g  
//是否结束while循环 }'dnL  
boolean breakWhile = false; }> k9]Y  
9}Tf9>qP>M  
W$@q ~/E  
while(!bStop) [1'`KJ]  
{ 4^VY  
write_nPos(); C_?L$3 U0  
Utility.sleep(500); *plsZ*Q8  
breakWhile = true; lNQt  
N\Bygjw|  
3=1aMQ  
for(int i=0;i<nStartPos.length;i++)  ;uNcrv0J  
{ mCe,(/>l+  
if(!fileSplitterFetch.bDownOver) M ]W'>g)G  
{ K Ii Vz<  
breakWhile = false; b5 YE4h8%  
break; )+Wx!c,mb  
} FGBPhH% (8  
} }%[TJ@R;  
if(breakWhile) y@'8vOh`  
break; {IJV(%E   
3x9O<H}  
V< 0gD?Kx  
//count++; [a\:K2*'  
//if(count>4) @#1k+tSA,  
// siteStop(); )H#Hs<)Qy  
} Er Ji  
db:b%1hk:  
1agyT  
System.err.println("文件下载结束!"); eb2~$ ,$  
} *@l NL=%R  
catch(Exception e){e.printStackTrace ();} m,$oV?y>j  
} Ck2O?Ne  
gpsEN(.w  
too=+'<N</  
//获得文件长度 RyC]4 QyC  
public long getFileSize() BV$lMLD{r  
{ gQgG_&xkC  
int nFileLength = -1; PkQuN;a  
try{ 9zEO$<e o  
URL url = new URL(siteInfoBean.getSSiteURL()); ~qLbyzHaB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I)V2cOrXM  
httpConnection.setRequestProperty("User-Agent","NetFox"); Vp\BNq_!s  
=U!'v X d  
CN\SxK`,  
int responseCode=httpConnection.getResponseCode(); j/{F#auI  
if(responseCode>=400) {LbNKjn  
{ eHi|_3A&*  
processErrorCode(responseCode); mKtZ@r)u  
return -2; //-2 represent access is error (tP>z+  
} *j2P#et  
EYd`qk 3  
+?[TH?2c+  
String sHeader; xaX3<V@S  
QS,IM >Nr  
\CM(  
for(int i=1;;i++) 7qV_QZ!.  
{ bqN({p&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); y'xB? >|  
//Utility.log(in.readLine()); 7w_`<b6  
sHeader=httpConnection.getHeaderFieldKey(i); ej47'#EY  
if(sHeader!=null) +,9I3Dq  
{ xvQJTR k  
if(sHeader.equals("Content-Length")) c~b[_J)  
{ !v<r=u  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,(}7 ST  
break; abuHu'73  
} bKYLBu:  
} [Oe$E5qv)]  
else FEw51a+V  
break; 5Jd&3pO  
} FAJ\9  
} ! ]&a/$U  
catch(IOException e){e.printStackTrace ();} aJ88U69  
catch(Exception e){e.printStackTrace ();} 6 9ia #  
U_m<W$"HF  
m.EI("n"J  
Utility.log(nFileLength); !m^;Apuy  
s\1h=V)!H  
pvQw+jX  
return nFileLength; u1/4WYJeJ  
} :h=];^/E  
a9mLPP  
I1BVqIt1i  
//保存下载信息(文件指针位置) v$s3f|Y  
private void write_nPos() `QXO+'j4  
{ )t9<cJ=  
try{ 2PE|4zG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); HvN!_}[  
output.writeInt(nStartPos.length); _-x|g~pV*  
for(int i=0;i<nStartPos.length;i++) di>"\On-  
{ 2B3H -`  
// output.writeLong(nPos); YH&`+ +  
output.writeLong(fileSplitterFetch.nStartPos); f%` =>l  
output.writeLong(fileSplitterFetch.nEndPos); b/5?)!I  
} SN(:\|f 2  
output.close(); kq8:h  
} {'E%SIRZ)  
catch(IOException e){e.printStackTrace ();} 1T!b# x4  
catch(Exception e){e.printStackTrace ();} "n," >  
} xmb]L:4F  
IkFrzw p  
v*<hE>J0  
//读取保存的下载信息(文件指针位置) jxL} tS{j  
private void read_nPos() "yXKu)_  
{ lPSyFb"  
try{ Zk__CgS#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /T]2ZX>  
int nCount = input.readInt(); H ifKa/}P8  
nStartPos = new long[nCount]; /@X!  
nEndPos = new long[nCount];  U2  
for(int i=0;i<nStartPos.length;i++) T=(/n=  
{ t,M _  
nStartPos = input.readLong(); VUxuX5B3M  
nEndPos = input.readLong(); ZZ?0%9  
} E?z3 D*U  
input.close(); __teh>MC  
} ^Wo/vm*]  
catch(IOException e){e.printStackTrace ();} <iuESeDG  
catch(Exception e){e.printStackTrace ();} )o;/*h%@  
} iagl^(s  
a$yAF4HR<  
aTuD|s  
private void processErrorCode(int nErrorCode) e) 42SL^s  
{ f 5"1WtB  
System.err.println("Error Code : " + nErrorCode); u\ro9l  
} G|Rsj{2'  
7"@^JxYN  
^[,Q2MHCT(  
//停止文件下载 d&4 ve Lu  
public void siteStop() M(KsLu1   
{ ExeD3Zj  
bStop = true; =,$*-<p=3  
for(int i=0;i<nStartPos.length;i++) R8I%Cyc  
fileSplitterFetch.splitterStop(); f_Ma~'3   
dKTyh:_{  
3p6QJuSB  
} Oq@+/UWX  
} f6vhW66:?x  
//负责部分文件的抓取 njtz,qt_;G  
**FileSplitterFetch.java 2 -72 8  
*/ ukpbx;O:hc  
package NetFox; {^=T&aCYdS  
"s]r"(MX  
aUa.!,_dh  
import java.io.*; a$r- U_?  
import java.net.*; $nF|n+m  
.A<G$ db ?  
/2l&D~d"  
public class FileSplitterFetch extends Thread { Z8E-(@`q5Q  
EudX^L5U<d  
Yz]c'M@  
String sURL; //File URL r*HbglB  
long nStartPos; //File Snippet Start Position #%N v\ g;  
long nEndPos; //File Snippet End Position M<^]Ywq*p  
int nThreadID; //Thread's ID 7aRtw:PQn  
boolean bDownOver = false; //Downing is over fqrQ1{%UH  
boolean bStop = false; //Stop identical V 6I77z  
FileAccessI fileAccessI = null; //File Access interface `|coA2$rw  
$9+|_[ ]v.  
FlGU1%]m  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException J!Er%QUR  
{ :dq.@:+<R  
this.sURL = sURL; 94VtGg=b}  
this.nStartPos = nStart; J{;XNf =  
this.nEndPos = nEnd; KBE3q)  
nThreadID = id; .2"-N5Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m:B9~ lbT+  
} E@ J/_l;  
M2H +1ic  
(StX1g'  
public void run() 60,z!Vv  
{ T<yAfnTb`  
while(nStartPos < nEndPos && !bStop) X-LCIT|1  
{ /By:S/[1pL  
|y9(qcKn$  
v+Eub;m   
try{ 0DtewN{Z  
URL url = new URL(sURL); 2[~|#0x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ak3cE_*Y/  
httpConnection.setRequestProperty("User-Agent","NetFox"); %O6r  
String sProperty = "bytes="+nStartPos+"-"; !q\MXS($#u  
httpConnection.setRequestProperty("RANGE",sProperty); ]QKo>7%[  
Utility.log(sProperty); p3r("\Za,  
GsIVx!  
>[}lC7 z,  
InputStream input = httpConnection.getInputStream(); R !g'zS'  
//logResponseHead(httpConnection); GWFF.Mo^  
yq.<,b=87  
f~Y;ZvB  
byte[] b = new byte[1024]; F<.oTP-B  
int nRead; ezimQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ! Gob `# r  
{ <*JFY%y "  
nStartPos += fileAccessI.write(b,0,nRead); qm^|7m^  
//if(nThreadID == 1) "5<:Dj/W  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ( jACLo  
} GuK3EM*_  
P5Lb)9_Jw  
L~oy|K67  
Utility.log("Thread " + nThreadID + " is over!"); "<Ozoo1&w  
bDownOver = true; L4O.=*P1  
//nPos = fileAccessI.write (b,0,nRead); r{ >Q{$Q  
} UE9RrfdN  
catch(Exception e){e.printStackTrace ();} W(pq_H'  
} :eIi^K z[  
} Z8C~o)n9  
l266ufO.u-  
}1fi#  
//打印回应的头信息 Cj%n?-  
public void logResponseHead(HttpURLConnection con) ;w/@_!~  
{ >?<S(  
for(int i=1;;i++) Tp46K\}Uf  
{ T@wgWE<0y_  
String header=con.getHeaderFieldKey(i); 5{/uHscwLa  
if(header!=null) 'oKen!?A  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); u9nJ;:  
Utility.log(header+" : "+con.getHeaderField(header)); |I[/Fl:  
else "; 1@f"kw  
break; P~ : N  
} d1P|v( `S9  
} "QD>m7  
"I3 #/~q  
8 Y4mTW  
public void splitterStop() IR2=dQS  
{ dx@|M{jz'  
bStop = true; Mj&G5R~_  
} s$%t2UaV  
Vv54;Js9  
 `j1oxJm  
} azz=,^U#  
\sMe2OL#z  
*\.8*6*$!  
/* rJZR8bo  
**FileAccess.java lArKfs/   
*//文件访问(定位,写) +7\d78U  
package NetFox; '-U&S  
import java.io.*; ]p8 zT|bv  
p}oGhO&=  
/4*Y#IpZ  
public class FileAccessI implements Serializable{ 2FR+Z3&z  
!4-4i  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X+1Mv  
RandomAccessFile oSavedFile; d-3.7nJ:  
long nPos; /#WvC;B  
V7b;qC'  
]_BH"ng}  
public FileAccessI() throws IOException Q,K$)bM  
{ ({ O~O5k  
this("",0); %pIP#y[4  
} {E; bT|3z  
.TMLg(2hgv  
}* \*<d 3  
public FileAccessI(String sName,long nPos) throws IOException ,ZghV1z  
{ [ *Dj7z t:  
oSavedFile = new RandomAccessFile(sName,"rw"); y8_$YA/g  
this.nPos = nPos; b)@D@K"5  
oSavedFile.seek(nPos); ?3lA ogB  
} ph}%Ay$  
2x>7>;>  
a^={X<K|/  
public synchronized int write(byte[] b,int nStart,int nLen) MyZVx|7 E  
{ ZIKSHC9  
int n = -1; ,Nt^$2DZW  
try{ t~7OtPF  
oSavedFile.write(b,nStart,nLen); ]1FLG* sB  
n = nLen; TjDtNE  
} 'hE'h?-7  
catch(IOException e) cZJ5L>ox  
{ Y[l<fbh(}  
e.printStackTrace (); ^,0Lr$+  
} lb$_$+@Vr  
eT Fep^[  
pd B\D  
return n; CT5s`v!s  
} N>Ih2>8t  
W]oa7VAq  
76bMy4re  
} hxzA1s%~  
CuD}Uo+u  
m.p $f$A_  
/* C6EGM/m8  
**SiteInfoBean.java C{,^4Eh3r  
*/ 9dw* ++  
package NetFox; XUzOt_L5<  
p^|6 /b  
wZZ~!"O &  
public class SiteInfoBean { N8pV[\f  
.X qeO@z  
HMC-^4\%[  
private String sSiteURL; //Site's URL  =n5n  
private String sFilePath; //Saved File's Path _Dd>e=v  
private String sFileName; //Saved File's Name #|4G,!  
private int nSplitter; //Count of Splited Downloading File =\_gT=tZ  
jz`3xFy *]  
7Q]c=i cg  
public SiteInfoBean() `LNhamp  
{//nSplitter的缺省值为5 iGSA$U P|  
//default value of nSplitter is 5 Y/6>OD  
this("","","",5); `!t-$i  
} ~|9VVeE  
zz[fkH3  
B2oKvgw  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'da 'WZG  
{ #bBh. ^  
sSiteURL= sURL; UOsK(mB  
sFilePath = sPath; #M{qMJHDo  
sFileName = sName; ,#FP]$FK  
this.nSplitter = nSpiltter; gyD;kn\CP  
H<[~V0=  
)l$}plT4  
} $'I&u  
D HT^.UM28  
3rB0H   
public String getSSiteURL() ,,BP}f+l$  
{ =/_uk{  
return sSiteURL; _XT'h;m  
} $,2T~1tE  
Bcarx<P-p  
4xEw2F  
public void setSSiteURL(String value) mE`qA*=?  
{ SOq:!Qt  
sSiteURL = value; W^H3=hZ  
} 9sT5l"?g  
$:%E<j 4Dn  
}04mJY[  
public String getSFilePath() _crhBp5@T3  
{ ka!v(j{E  
return sFilePath; ,5"(m?[m  
} aUzCKX%>C  
oWL_Hh%-f`  
u1L^INo/  
public void setSFilePath(String value) }rI:pp^KS  
{ p09p/  
sFilePath = value; ?!&%-R6*  
} C&>*~  
@`dg:P*[  
GE(~d '  
public String getSFileName() 3PGAUQR#"q  
{ _<LL@IX  
return sFileName; @U18Dj[  
} i4,p\rE0  
BH1h2OEe#  
w^ut,`yW R  
public void setSFileName(String value) oR&z,%0wMK  
{ jtlRom}  
sFileName = value; ?T2>juf]5~  
} n V7Vc;  
o^vX\a?`u  
E Izy  
public int getNSplitter() .dk<?BI#H  
{ 7Vsp<s9bj  
return nSplitter; A$3Rbn}"  
} R`cP%7K  
o(oOB  
a3<:F2=~\  
public void setNSplitter(int nCount) @2/|rq  
{ 1f}(=Hv{  
nSplitter = nCount; uD>=  
} N=BG0t$  
} R ,qQC<  
>< $LV&  
WA8<:#{e  
/* @wgd 3BU  
**Utility.java #dj?^n g  
*/ uy'seJ  
package NetFox; )rK2%\Z  
(tX3?[ii  
+ODua@ULFB  
public class Utility { OALNZKP  
x_nwD"   
WJOoDS!i  
public Utility() (MI>7| ';  
{  ~2"hh$  
h<U?WtWT-p  
+T$Olz  
} &\N>N7/1  
teg5g|*  
//线程睡眠 HCs^?s8Pp  
public static void sleep(int nSecond) gHLI>ew*QR  
{ JP5e=Z<  
try{ E(P 6s;LZ  
Thread.sleep(nSecond); FKTF?4+\U  
} ;"Kgg:K>W  
catch(Exception e) D#b*M)X"  
{ 8x U*j  
e.printStackTrace (); -!Myw&*\V  
} Kd`(^  
} a)JXxst  
g[O?wH-a  
//日志 d fj23+  
public static void log(String sMsg) N $) G 8  
{ W5 F\e[Ax5  
System.err.println(sMsg); "Gp[.=.z?  
} 985F(r  
HE,L8S  
K:a8}w>Up  
public static void log(int sMsg) m!/TJhiQ  
{ 2bNOn%!  
System.err.println(sMsg); Cf=H~&`Z  
} [i`  
} LpU}.  
V:kRr cX  
.J)TIc__|A  
/* T;/GHC`{Y  
**TestMethod.java |#@7$#j  
*/ ?8-!hU@QC  
package NetFox; 'q-q4 QCB  
z l@^[km{  
hy*{ {f;  
public class TestMethod { *8Z2zmZtR^  
[CI&4) #  
w(Z?j%b  
public TestMethod() Sf*)Z3f  
{ ///xx/weblogic60b2_win.exe ]nhh|q9r{  
try{ NUFz'MPv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5l6/5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); qNQ54#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); e^Zm09J  
fileFetch.start(); VI2lw E3  
} fHup&|.  
catch(Exception e){e.printStackTrace ();} 4!/JN J  
/| v.A\ :  
<kK>C8+  
} 7AV{ h[J  
2tq2   
uQ5h5Cfz  
public static void main(String[] args) -F~DOG%  
{ d. wGO]"  
new TestMethod(); Tc6cBe,  
} IL].!9  
} Z+El(f x  
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