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http断点续传简单实现(java)

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/* w8R7Ksn(  
**SiteFileFetch.java yo->mD  
*/ =0] K(p,  
package NetFox; - _ 8-i1?  
import java.io.*; H"(#Tp ZTE  
import java.net.*; G4*&9Wo  
f S/:OnH  
F-rhxJd  
public class SiteFileFetch extends Thread { vs[!B-  
#::+# G  
{<@ud0A:\  
SiteInfoBean siteInfoBean = null; //文件信息Bean /;+\6(+X  
long[] nStartPos; //开始位置 9  @ <  
long[] nEndPos; //结束位置 ar\|D\0V  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _s#]WyU1g  
long nFileLength; //文件长度 iKV|~7nwO  
boolean bFirst = true; //是否第一次取文件 ;$zvm`|:  
boolean bStop = false; //停止标志 l7jen=(Zb;  
File tmpFile; //文件下载的临时信息 2wB *c9~  
DataOutputStream output; //输出到文件的输出流 } % Ie  
3IQI={:k|D  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) |v8h g])I+  
public SiteFileFetch(SiteInfoBean bean) throws IOException J&fIW Z  
{ 9xz@2b@  
siteInfoBean = bean; &z40l['4bz  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &U?4e'N)T  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ``k[CgV  
if(tmpFile.exists ()) .U=x2txb  
{ ;lb  
bFirst = false; ;YY<KuT  
read_nPos(); <(@S;?ZEW  
} \ui'~n_t]  
else 9/e>%1.  
{ \P+^BG!  
nStartPos = new long[bean.getNSplitter()]; y[85eM  
nEndPos = new long[bean.getNSplitter()]; ; 8DtnnE  
} Vdx o  
ru2M"]T  
{+_p?8X  
hvO$ f.i  
} e,p*R?Y{[  
5o 5DG  
;z9 ,c  
public void run() aV|V C $  
{ \9OKf|#j  
//获得文件长度 =,;$d&#*h  
//分割文件 -r<8mL:yW  
//实例FileSplitterFetch j>;1jzr2}  
//启动FileSplitterFetch线程 UakVmVN/P  
//等待子线程返回 kP[fhOpn  
try{ |3E|VGm~  
if(bFirst) 4[x` \  
{ *,CJ 3< >  
nFileLength = getFileSize(); B*O/>=_  
if(nFileLength == -1) pXlqE,  
{ :Bt,.uN C  
System.err.println("File Length is not known!"); [Z2[Iy  
} CSoVB[vS  
else if(nFileLength == -2) 2HBey  
{ U W8yu.`?  
System.err.println("File is not access!"); IoJI|lP  
} GqsV 6kH  
else +u=VO#IA#  
{ *&IvEu  
for(int i=0;i<nStartPos.length;i++) wT- -i@@  
{ ]!^wB 3j  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tlD^"eq4:  
} *q=\ e9  
for(int i=0;i<nEndPos.length-1;i++) s?m_zJh  
{ xg, 9~f[  
nEndPos = nStartPos[i+1]; xLFMC?I  
} ~E8/m_> rU  
nEndPos[nEndPos.length-1] = nFileLength; W&cs&>F#  
} zj2y=A| Y  
} r`sKe &  
zfI{cMn'J  
Zy9IRZe4U  
//启动子线程 9]ZfSn)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nM &a2Z,T  
for(int i=0;i<nStartPos.length;i++) k)D5>T  
{ > O?<?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eQ)*jeD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <5j%!6zo  
nStartPos,nEndPos,i); "2-D[rYZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LqI&1$#  
fileSplitterFetch.start(); _i7yyt;h  
} EX!`Zejf  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `5oXf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @>$qb|j  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", jPz1W4pk  
nEndPos = " + nFileLength); GY@:[u.&  
// fileSplitterFetch[nPos.length-1].start(); seAPVzWUU  
<w*WL_P  
0S>L0qp  
//等待子线程结束 ](n)bF+ym  
//int count = 0; l?_Fy_fBt  
//是否结束while循环 XABP}|aWK  
boolean breakWhile = false; JQej$=*  
6hR ` sE  
F?FfRzZ[  
while(!bStop) #b)`as?!1  
{ [+W<;iep  
write_nPos(); Yc6.v8a  
Utility.sleep(500); ~;]zEq-hG  
breakWhile = true; vN_ 8qzWk  
kzK9 .  
Hq gg*4#  
for(int i=0;i<nStartPos.length;i++) fyT|xI`iD  
{ nvwf!iU6  
if(!fileSplitterFetch.bDownOver) b?,%M^9\`  
{ :EYUBtTj  
breakWhile = false; ` s+kYWg'Z  
break; :Sd`4"AA  
} H0])>1sWB  
} 8_Uh h5[  
if(breakWhile) (xTGt",_Jo  
break; $'eY-U8q  
k$f2i,7'  
;-"q;&1e  
//count++; 9I<~t@q5e@  
//if(count>4) +G"YQq'b  
// siteStop(); GNrRc3dr$  
} bd}[X'4d  
H n]( )/  
0J466H_d{  
System.err.println("文件下载结束!"); b3 =Z~iLv  
} YIgHLM(  
catch(Exception e){e.printStackTrace ();} (G{S*+  
} :O&jm.2m  
dXM8iP  
Y}2Sr-@u  
//获得文件长度 `[}X_d 1A  
public long getFileSize() zAklS 7L  
{ ?D)$O CS  
int nFileLength = -1; *pnaj\  
try{ %-K5sIz  
URL url = new URL(siteInfoBean.getSSiteURL()); -$g~,dIwj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @b.,pwZF  
httpConnection.setRequestProperty("User-Agent","NetFox"); KDGrX[L:6  
'PFjZGaKR  
FAM:; F30  
int responseCode=httpConnection.getResponseCode(); #QcRN?s  
if(responseCode>=400) @+p(%  
{ /)K;XtcN  
processErrorCode(responseCode); ]63! Wc  
return -2; //-2 represent access is error u=]*,,5<  
}  !=*8*?@  
ew dTsgt'  
vV 9vB3K5?  
String sHeader; 0#uB[N  
c[ 0`8s!  
Piwox1T ;  
for(int i=1;;i++) ,!%E\`  
{ emrA!<w!W  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "sDs[Lcq  
//Utility.log(in.readLine()); lP]Y^Gz  
sHeader=httpConnection.getHeaderFieldKey(i); OQ wO7Z  
if(sHeader!=null) z9OpxW@Ou  
{ ,tyPZR_  
if(sHeader.equals("Content-Length")) j} ^3v #  
{ 5}]+|d;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $Q'z9ghEg  
break; X9FO"(J  
} 4L{]!dox  
} kMnG1K  
else U{pg y#/  
break; ]a~sJz!  
} N#e9w3Rli  
} =VZ_';b h  
catch(IOException e){e.printStackTrace ();} ?(K=du  
catch(Exception e){e.printStackTrace ();} \>lA2^E f  
2?Jw0Wq5D  
Xfqin4/jC  
Utility.log(nFileLength); m}RZ )c  
m9:ah<  
1%N*GJlwJ  
return nFileLength; ?f q!BV  
} g%[:wjV;  
v;;3 K*c>  
8uH8)  
//保存下载信息(文件指针位置) vo*oCfm  
private void write_nPos() `Z5dRLrd  
{ VR&dy|5BO  
try{ Z^as ?k(iM  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S!z3$@o  
output.writeInt(nStartPos.length); |#Lz0<c;  
for(int i=0;i<nStartPos.length;i++) y1PyH  
{ ,~ZD"'*n6g  
// output.writeLong(nPos); $*%,  
output.writeLong(fileSplitterFetch.nStartPos); ?H@<8Ra=3  
output.writeLong(fileSplitterFetch.nEndPos); gSw <C+  
} $rr@3H+  
output.close(); "uIaKb  
} \$Wpt#V  
catch(IOException e){e.printStackTrace ();}  @,k5T51m  
catch(Exception e){e.printStackTrace ();} (Y7zaAG]  
} 5BXku=M  
$S?gQN.e  
"H`Be  
//读取保存的下载信息(文件指针位置) ][?J8F  
private void read_nPos() >J S^yVk  
{ ^4"AWps  
try{ sr&W+4T  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0D@$  
int nCount = input.readInt(); !\BZ_guz  
nStartPos = new long[nCount]; 1Pw1TO"Z  
nEndPos = new long[nCount]; ^w~B]*A :"  
for(int i=0;i<nStartPos.length;i++) g:JSy  
{ $'Mf$h  
nStartPos = input.readLong(); Q35\wQ#  
nEndPos = input.readLong(); bK~Toz< k  
} Sm4BZF~!B  
input.close(); At=d//5FFP  
} 8/dMvAB1So  
catch(IOException e){e.printStackTrace ();} LPJ7V` !k  
catch(Exception e){e.printStackTrace ();} sV%DX5@  
} =NC??e{  
P o@;PR=  
|w{Qwf!2  
private void processErrorCode(int nErrorCode) U[?_|=~7  
{ Zc1x"j  
System.err.println("Error Code : " + nErrorCode); 5{V"!M+<  
} 1r$-Uh  
T Q4L~8  
}5oI` 9VT  
//停止文件下载 6 V0Ayxg7  
public void siteStop() #Iz)Mu  
{ #c@&mus  
bStop = true; 13 #ff  
for(int i=0;i<nStartPos.length;i++) nD*iSb*  
fileSplitterFetch.splitterStop(); qovsM M  
<.4(#Ebd  
N?vb^?  
} Vl5>o$G|<.  
} L7 }nmP>aR  
//负责部分文件的抓取 ;HXk'xN  
**FileSplitterFetch.java $-1ajSVJ  
*/ 0x-g0]  
package NetFox; 2n@`O g_0  
PtW2S 1?j  
t7F0[E'=5\  
import java.io.*; 2'S&%UyP  
import java.net.*; d%'#-w'  
`Fr ,,Q81\  
2\1+M)  
public class FileSplitterFetch extends Thread { {HEWU<5  
AtCT  
\]Ah=`  
String sURL; //File URL o( zez  
long nStartPos; //File Snippet Start Position (cLKhn@  
long nEndPos; //File Snippet End Position jC>ZMy8U)4  
int nThreadID; //Thread's ID N { oVz],  
boolean bDownOver = false; //Downing is over Nz`8)Le  
boolean bStop = false; //Stop identical T"Y#u  
FileAccessI fileAccessI = null; //File Access interface <9fXf*  
H;nzo3x  
Zio! j%G  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y`ip. Nx  
{ *% ;A85V/  
this.sURL = sURL; 9S]pC?N]E  
this.nStartPos = nStart; ~&)\8@2  
this.nEndPos = nEnd; U%:%. Bys  
nThreadID = id; Ljz)%y[s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?l6yLn5si^  
} a^J(TW/  
/8qR7Z^HZ  
Hl8-q!  
public void run() mnM]@8^G  
{ sX~E ~$_g  
while(nStartPos < nEndPos && !bStop) |(%<FY$  
{ n>.@@  
g3kbsi7_:  
Hu<]*(lK%  
try{ lot`6]  
URL url = new URL(sURL); @QmN= X5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wd*B3  
httpConnection.setRequestProperty("User-Agent","NetFox"); H I|a88   
String sProperty = "bytes="+nStartPos+"-"; ]j7`3%4uK  
httpConnection.setRequestProperty("RANGE",sProperty); p+=zl`\=|  
Utility.log(sProperty); AJi+JO-  
t!rrYBSCr  
3'.3RKV  
InputStream input = httpConnection.getInputStream(); }~@/r5Zl  
//logResponseHead(httpConnection); r[Pp[ g-J  
2K>1,[C'Z  
p4z4[=-:  
byte[] b = new byte[1024]; ),N,!15j,  
int nRead; UiV#w#&P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) eWv:wNouk  
{ QO;Dyef7b  
nStartPos += fileAccessI.write(b,0,nRead); 'hr_g* i  
//if(nThreadID == 1) `e'wW V  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Jt]RU+TB  
} %l&oRBC  
kBk>1jn"  
~F-knEvL  
Utility.log("Thread " + nThreadID + " is over!");  Q(w;  
bDownOver = true; ^?Xs!kJP  
//nPos = fileAccessI.write (b,0,nRead); }'wZ)N@  
} "|(.W3f1  
catch(Exception e){e.printStackTrace ();} %|H]T] s  
} eoww N>-2C  
} Y(6ev o&IR  
`G!HGzVx;j  
Nxt:U{`T'  
//打印回应的头信息 &'^.>TJ\  
public void logResponseHead(HttpURLConnection con) *ilh/Hd>  
{ H}GGUE&c*  
for(int i=1;;i++) \l(J6Tu  
{ 1#3|PA#>  
String header=con.getHeaderFieldKey(i); (mP{A(kwJ  
if(header!=null) FLG"c690  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )lLeL#]FLO  
Utility.log(header+" : "+con.getHeaderField(header)); _(g0$vRP~  
else 15J"iN2"W  
break; %]7 6u7b/  
} b|.Cqsb  
} t!3s@  
lv/im/]v  
X>`03?L  
public void splitterStop() qZF&^pCF}  
{ mmJnE  
bStop = true; py\:u5QS  
} AJB NM  
stK}K-=`  
f@YdL6&d-  
} U)f('zD  
nxhlTf>3  
P]n0L4c  
/* m2^vH+wD  
**FileAccess.java M>5OC)E  
*//文件访问(定位,写) "|I.j)  
package NetFox; C~4SPCU  
import java.io.*; J|{50?S{^  
v|~=rvXFC  
swZi O_85  
public class FileAccessI implements Serializable{ uz+ WVmb  
A^FkU  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #pPOQv:~  
RandomAccessFile oSavedFile; .n8O 3V  
long nPos; 6e# wR/  
M/#U2!iFk  
t77'fm  
public FileAccessI() throws IOException v459},!P  
{ ]fE3s{y &-  
this("",0); F;kvH  
} V#J"c8n  
oLS7`+b$  
tS<h8g_  
public FileAccessI(String sName,long nPos) throws IOException fY_%33_I$  
{ e+@xs n3  
oSavedFile = new RandomAccessFile(sName,"rw"); b_vTGl1_6  
this.nPos = nPos; {eR9 ;2!  
oSavedFile.seek(nPos); S}cF0B1E*  
} v[&'k\  
fHfY}BQS  
nxQ}&n  
public synchronized int write(byte[] b,int nStart,int nLen) XLb0 9;  
{ Hku=pr3Gn  
int n = -1; fsvYU0L  
try{ k1fRj_@WPT  
oSavedFile.write(b,nStart,nLen); 31}W6l88c  
n = nLen; 0S.?E.-&0  
} rk,p!}FqL  
catch(IOException e) -H\,2FO  
{ u D(t`W"  
e.printStackTrace (); J]fS({(\I  
} t5) J;0/  
"'A"U  
V;93).-$  
return n; ;|TT(P:d  
} qks|d_   
f1Zt?=  
TpP8=8_Lh  
} |Q!4GeQL[  
-t4 [oB  
Q4wc-s4RN  
/* 5AOfp2O  
**SiteInfoBean.java Jqru AW<  
*/ 16$y`~c-z  
package NetFox; R2LK.bTVn  
<zfKC  
CgnXr/!L  
public class SiteInfoBean { 6[?}6gQ  
1q]c7"  
ut5yf$%  
private String sSiteURL; //Site's URL wFL3& *  
private String sFilePath; //Saved File's Path ez*jjm  
private String sFileName; //Saved File's Name %S#WPD'Y  
private int nSplitter; //Count of Splited Downloading File >5Lexj  
NHiq^ojk  
&qRJceT(  
public SiteInfoBean() Q6^x8  
{//nSplitter的缺省值为5 0YS?=oi  
//default value of nSplitter is 5 EXpSh}  
this("","","",5); 0H:dv:#WAI  
} @GG ccF  
[ rdsv  
\9/1L ?@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )|]Z>>%t  
{ hz)9"B\S  
sSiteURL= sURL; 4P kfUMX  
sFilePath = sPath; {L0;{  
sFileName = sName; nGrVw&  
this.nSplitter = nSpiltter; yP\Up  
0"4@;e_)>  
8D~x\!(p\  
} BUC,M:J+H  
X\sm[_I  
T[.[ g/`  
public String getSSiteURL() (@&I_>2Q  
{ x / XkD]Hq  
return sSiteURL; nNn56&N]  
} e.;M.8N#SQ  
I/p]DT  
L11L23:  
public void setSSiteURL(String value) 'sU)|W(3U  
{ _CdROo6I  
sSiteURL = value; LprM;Q_  
} =!<G!^  
>oqZ !V5[  
9]$`)wZ  
public String getSFilePath() ^ KH>1!  
{ V5 MO}  
return sFilePath; [7\>"v6  
} f a5]a  
,w`~K:b.  
a %K}j\M  
public void setSFilePath(String value) {Y_Nj`#BT  
{ jA`a/v Wu  
sFilePath = value; ;KcFy@ 6q5  
} ty- r&  
SrZ50Se  
- L~Uu^o  
public String getSFileName() PqEAqP  
{ a [C&e,)}  
return sFileName; =`p&h}h-L  
} $G[KT):N  
Y4To@TrN#\  
u!1/B4!'O  
public void setSFileName(String value) GqUSVQ  
{ _01Px a2.  
sFileName = value; YIO R$  
} 3k{ @.V ?]  
J}@GKNm  
9X]f[^  
public int getNSplitter() Efr&12YSS  
{ )w"0w(   
return nSplitter; ;.s: X  
} /DU*M,  
8"M<{72U]  
g rbTcLSF  
public void setNSplitter(int nCount) V^En8  
{ 7a<_BJXx  
nSplitter = nCount; ]^@0+!  
} \_ -DyD#3  
} @ER1zKK?  
~zyQ('  
 cht  
/* xIgql}.  
**Utility.java }m_t$aaUc1  
*/ UC|JAZL  
package NetFox; AZ wa4n}"  
%fpsc _  
\!wh[qEQ\  
public class Utility { F^rl$#pCS  
}n95< {  
RVP18ub.S  
public Utility() $4Y&j}R  
{ t w!.%_1^  
}17bV, t  
76cEKHa<  
} ,?y7 ,nb  
*<k&#D"m  
//线程睡眠 k1iLnza%  
public static void sleep(int nSecond) C BlXC7_Mi  
{ XU-*[\K  
try{ ~:Ixmqi}R  
Thread.sleep(nSecond); q?i Cc c  
} hbnS~sva  
catch(Exception e) mJ$Htyr  
{ $e1:Q#den2  
e.printStackTrace (); <[9?Rj@  
} 3{pk5_c  
} SG`)PW?  
6Ahr_{  
//日志 yFO)<GLk  
public static void log(String sMsg) d h?dO`  
{ f".q9{+p,  
System.err.println(sMsg); R&!]Rl9hf  
} gvo?([j-m  
i;]CL[#2e`  
D1ZC&B_}-  
public static void log(int sMsg) f9F2U )  
{ :<UtHf<=k  
System.err.println(sMsg); 5Hy3\_ +  
} <Wf0QO,  
} eP?~- #  
kp; &cQu!  
mt^`1ekoY  
/* |h D~6a  
**TestMethod.java 6Pijvx^0  
*/ m9Il\PoTq  
package NetFox; 1t#XQ?8  
"ZqEP R)  
`:gYXeR  
public class TestMethod { QES^^PQe:  
UAKu_RO6S  
^(g_.>  
public TestMethod() LU G9 #.  
{ ///xx/weblogic60b2_win.exe dm  2EH  
try{ KcnjF^k  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  `~h0?g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6Wb!J>93  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )r pD2H  
fileFetch.start(); F;W'  
} :ovt?q8">  
catch(Exception e){e.printStackTrace ();}  RY9. n  
Onyh1  
?#i|>MRR>  
} F#KF6)P  
aC}p^Nkr"k  
X7b!;%3@  
public static void main(String[] args) o Fi) d[`  
{ jVs(x  
new TestMethod(); .=CH!{j  
} V4Qz*z%  
} k1m'Ka-  
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