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http断点续传简单实现(java)

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/* l2KR=& SX/  
**SiteFileFetch.java $;Lb|~  
*/ Lz2 AWqR  
package NetFox; &*RJh'o|N(  
import java.io.*; =YkJS%)M)  
import java.net.*; @ 'rk[S}A  
2`/JT  
wy"^a45h  
public class SiteFileFetch extends Thread { 0PD]#.+  
I&qT3/SVI  
Ce}wgKzr  
SiteInfoBean siteInfoBean = null; //文件信息Bean oqHI`Tu  
long[] nStartPos; //开始位置 6*Jd8Bva\o  
long[] nEndPos; //结束位置 >l{<p(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h|"98PI  
long nFileLength; //文件长度 \[oU7r}?/V  
boolean bFirst = true; //是否第一次取文件 &bBK#d*-u?  
boolean bStop = false; //停止标志 7yxZe4~|#  
File tmpFile; //文件下载的临时信息 D`PnY&ffT  
DataOutputStream output; //输出到文件的输出流 EAp6IhW{  
:\x53-&hO4  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) f sAgXv  
public SiteFileFetch(SiteInfoBean bean) throws IOException nk9Kq\2f:  
{ gUzCDB^.:  
siteInfoBean = bean; >up'`K,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); pXPwn(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); J6/Mm7R  
if(tmpFile.exists ()) RRig  
{ vU LlAQG  
bFirst = false; IwhZzw w  
read_nPos(); "*|plB  
} w35r\x +  
else 8=OK8UaU  
{ &Al9%W  
nStartPos = new long[bean.getNSplitter()]; pUki!TA  
nEndPos = new long[bean.getNSplitter()]; JS% &ipm  
} /Za'L#=R  
ww82)m8  
t=J\zyX!  
|ZW%+AQ|  
} 1ux~dP  
|rkj$s,  
iJuh1+6:c9  
public void run() I^ sWf3'db  
{ "&%: 9O  
//获得文件长度 5*~Mv<#  
//分割文件 $8h^R#  
//实例FileSplitterFetch |^Nz/PN  
//启动FileSplitterFetch线程 p"f=[awp  
//等待子线程返回 4thLK8/c5g  
try{ q3Re F_  
if(bFirst) $Z(fPKRN/  
{ uhvmh  
nFileLength = getFileSize(); N r5 aU6]  
if(nFileLength == -1) jC> l<d_  
{ rXXIpQRi$S  
System.err.println("File Length is not known!"); L {(\k$>'  
} ^l;nBD#nJ  
else if(nFileLength == -2) Z<6xQTx  
{ Vd^_4uqnV  
System.err.println("File is not access!"); 5f2ah4 g  
} cMOvM0f  
else :#v8K;C  
{ &x19]?D"+  
for(int i=0;i<nStartPos.length;i++) '{WYho!  
{ FU/yJy  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); " ,&#9  
} Va,M9)F  
for(int i=0;i<nEndPos.length-1;i++) "H\'4'hg  
{ Bi2be$nV  
nEndPos = nStartPos[i+1]; ;%P$q9 *C  
} sL|lfc'bB  
nEndPos[nEndPos.length-1] = nFileLength; wP3_RA]z  
} Tyt:Abym=  
} BUB#\v#a  
eSf e s  
q/ -8sO}q  
//启动子线程 }7YDe'5V  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; z:<mgp&/<  
for(int i=0;i<nStartPos.length;i++) [q]"_4L0;d  
{ A,D67G<v`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6T{Zee  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Z#YkAQHv5  
nStartPos,nEndPos,i); ! )$ PD@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V0+D{|thh6  
fileSplitterFetch.start(); |$@/ Z +  
} flp<QT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D7cOEL<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z!27#gbL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Gs%IZo_  
nEndPos = " + nFileLength); ""l_& 3oz  
// fileSplitterFetch[nPos.length-1].start(); ]z`Y'wSxd  
xMJF1O?3  
+cv7]  
//等待子线程结束 ;Vc@]6Ck  
//int count = 0; 6dQa|ACX_  
//是否结束while循环 Icf 4OAx  
boolean breakWhile = false; #+Z3!VS  
2xRb$QF  
uV.3g 1 m  
while(!bStop) ?PORPv#  
{ eA9U|&o  
write_nPos(); <Ur(< WTV  
Utility.sleep(500); E< nXkqD  
breakWhile = true; fo~8W`H&  
<e"O`*ZJ  
yO.3~H)c  
for(int i=0;i<nStartPos.length;i++) +;SQ }[  
{ o<P@:}K  
if(!fileSplitterFetch.bDownOver) a*JM2^,HO  
{ |,M&ks  
breakWhile = false; r*]0PQ{?  
break; lQQXV5NV  
} x bF*4;^SI  
} b2c% 0C  
if(breakWhile) Ry*NRP;  
break; -}|GkTM  
|qbCmsY5/  
i$[wgvJIV  
//count++; Xm`s=5%  
//if(count>4) 6ae  
// siteStop(); ]$(::'pmK  
} m)9N9Ii#)  
rZ<0ks  
> kOca  
System.err.println("文件下载结束!"); 'TpW-r:  
} l!e8=QlJ  
catch(Exception e){e.printStackTrace ();} l=*^FK]L`  
} |sz`w^#  
Ib.`2@ o&  
'JY*K:-  
//获得文件长度 n m(yFX?=  
public long getFileSize() hH:7  
{ TN3, \qgV  
int nFileLength = -1; 8}h ^Frh  
try{ h-hU=I8  
URL url = new URL(siteInfoBean.getSSiteURL()); hKjvD.6]%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6'ye-}vD-  
httpConnection.setRequestProperty("User-Agent","NetFox"); WmLl.Vv=  
Pi::cf>3  
Yu=4j9e_mG  
int responseCode=httpConnection.getResponseCode(); vfzGRr  
if(responseCode>=400) >R3~P~@30  
{ _H^Ij  
processErrorCode(responseCode); 6~GaFmW=  
return -2; //-2 represent access is error ;>[).fX>/  
} pW O-YZ#+  
=Xzqp,  
f ^mxj/%L  
String sHeader; 8,2l >S  
d}tn/Eu?B  
B#o(21s  
for(int i=1;;i++) Dr6"~5~9w  
{ OO_{ o  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LA$uD?YA  
//Utility.log(in.readLine()); 3P Twpq1  
sHeader=httpConnection.getHeaderFieldKey(i); 0K7]<\)  
if(sHeader!=null) pVn 6>\xa  
{ lqA U5K{wQ  
if(sHeader.equals("Content-Length")) USu/Y29  
{ (FZL>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); E>TD`  
break; m s\:^a  
} 6"WR}S0o  
} A=|LMJMWR  
else l;U9dO}/[  
break; JGt4B  
} 'GQ1;9A57  
} vq_W zxaG  
catch(IOException e){e.printStackTrace ();} a{Y:hrd:Z  
catch(Exception e){e.printStackTrace ();} DCX 4!,ZF  
@I}:HiF  
>=^g%K$L6J  
Utility.log(nFileLength); mU:C{<Z  
tp$NT.z  
>#dNXH]9  
return nFileLength; Q6Q>b4 .3  
} R6dw#;6{I  
=%Gecj  
n|NI]Qi*  
//保存下载信息(文件指针位置) R?1;'pvpa[  
private void write_nPos() X obiF  
{ $f>Mz|j  
try{ W-=~Afy  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^te9f%>$l  
output.writeInt(nStartPos.length); CZE5RzG  
for(int i=0;i<nStartPos.length;i++) t)g1ICt  
{ Zb-TCS+3l  
// output.writeLong(nPos); f[ GH  
output.writeLong(fileSplitterFetch.nStartPos); MUz.-YRt  
output.writeLong(fileSplitterFetch.nEndPos); oLk>|J  
} a}`4BMi3  
output.close(); +^<CJNDL9  
} hF+YZU]rT  
catch(IOException e){e.printStackTrace ();} \l_RyMi  
catch(Exception e){e.printStackTrace ();} .rSeJZzuj  
} ] =b?^'  
:Y y+%  
al=Dy60|z  
//读取保存的下载信息(文件指针位置) bj(U?$  
private void read_nPos() kxoJL6IC  
{ O(,Ezy x  
try{ ru3nnF_I  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); m\U@L+L  
int nCount = input.readInt(); ?nrd$,  
nStartPos = new long[nCount]; ^C>i(j&  
nEndPos = new long[nCount]; ;E:ra_l  
for(int i=0;i<nStartPos.length;i++) ?v#t{e0eQ  
{ MR%M[SK1  
nStartPos = input.readLong(); Rb<aCX  
nEndPos = input.readLong(); 3s\2 9gq  
} !40{1U&@a`  
input.close(); LYGFE jS[  
} V!c{%zd  
catch(IOException e){e.printStackTrace ();}  {"y{V  
catch(Exception e){e.printStackTrace ();} QV+('  
} G9z Q{E  
\%&QIe;:k  
g6Qzkvw)  
private void processErrorCode(int nErrorCode) :g'"*VXYB  
{ Y%p"RB[  
System.err.println("Error Code : " + nErrorCode); tb AN{pX  
} {i~qm4+o  
a~OCo  
CY)Wuv ^  
//停止文件下载 ~t<BZu  
public void siteStop() ;W?e@ Lgxk  
{ 2{"Wa|o`  
bStop = true; 8l>/ZZ.NXi  
for(int i=0;i<nStartPos.length;i++) L GK0V!W  
fileSplitterFetch.splitterStop(); [[JwHM8H&  
%&Z!-k(  
!rb)Y;WQt  
} J\_tigd   
} !-x^b.${B  
//负责部分文件的抓取 VyCBJK  
**FileSplitterFetch.java .zlUN0oe  
*/ N-3w)23*:  
package NetFox; h_?D%b~5  
h\C  
|=l;UqB  
import java.io.*; -DX|[70  
import java.net.*; Y!i4P#4+q  
e.\d7_T+  
H h$D:ZO  
public class FileSplitterFetch extends Thread { | g> K$m^  
fcr\XCG7U  
!K'kkn,h  
String sURL; //File URL :b^tu 8E  
long nStartPos; //File Snippet Start Position (BMFGyE3  
long nEndPos; //File Snippet End Position Cf<i"   
int nThreadID; //Thread's ID ~c! XQJ  
boolean bDownOver = false; //Downing is over p8[Z/]p  
boolean bStop = false; //Stop identical U;;vNzcn  
FileAccessI fileAccessI = null; //File Access interface n0O- Bxhl  
bY+Hf\A  
}_3<Q\j  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException JmWN/mx  
{ pb$U~TvzhM  
this.sURL = sURL; -78 t0-lM  
this.nStartPos = nStart; `P)atQ  
this.nEndPos = nEnd; _R]la&^2F\  
nThreadID = id; rxIfatp^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *7nlel  
} <bXfjj6YJ@  
"1&C\}.7  
#]:yCiA  
public void run() TTmNPp4q  
{ `DC)U1  
while(nStartPos < nEndPos && !bStop) zvdtP'&uj  
{ ~( -B%Az  
rh${pHl  
3VB{Qj  
try{ $eX; 2  
URL url = new URL(sURL); 4tCyd5u a8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m-5Dbx!j  
httpConnection.setRequestProperty("User-Agent","NetFox"); zYYc#N/  
String sProperty = "bytes="+nStartPos+"-"; E >KV1P  
httpConnection.setRequestProperty("RANGE",sProperty); IBQmm(+v  
Utility.log(sProperty); Ts|&_|  
syv6" 2Z'B  
Xko[Z;4v8'  
InputStream input = httpConnection.getInputStream(); dW,$yH_  
//logResponseHead(httpConnection); opjrU$<]N  
NL0X =i  
"npj%O<bd  
byte[] b = new byte[1024]; My:wA;#  
int nRead; 1r\? uD  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) LC*@ /((  
{ 2y,NT|jp  
nStartPos += fileAccessI.write(b,0,nRead); mj%Iow.  
//if(nThreadID == 1) }Wn6r_:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?#rDoYt/Sx  
} $wdIOfaH  
Q^DKKp  
c3`X19'%fM  
Utility.log("Thread " + nThreadID + " is over!"); ka[]pY  
bDownOver = true; zRD{"uqi  
//nPos = fileAccessI.write (b,0,nRead);  z4&|~-m,  
} (JL{X`gs#  
catch(Exception e){e.printStackTrace ();} y2TJDb1  
} PC7U&*x@  
} * "~^k^_b}  
31  QT  
`Q, moz  
//打印回应的头信息 Qi w "x,  
public void logResponseHead(HttpURLConnection con)  *9`@  
{ SH<Nt[8C  
for(int i=1;;i++) #QXB2x<*  
{ +K; X$kB  
String header=con.getHeaderFieldKey(i); teg LGp@_  
if(header!=null) oZmni9*SD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *t 3fbD  
Utility.log(header+" : "+con.getHeaderField(header)); c9=;:E  
else p3\F1](Z  
break; A>bo Xcr  
} UCa(3p^V_  
} 3!Gnc0%c  
n* 9)Y~  
Z '/:  
public void splitterStop() ]Yp;8#:1  
{ `CUTb*{`  
bStop = true; }RO Cj,|  
} :&/'rMi<T  
,~hvFTJI  
&+xNR2";  
} p4fU/  
|/Ggsfmby  
(VI4kRj  
/* *A@~!@XE4  
**FileAccess.java /Pxt f~$  
*//文件访问(定位,写) *=$Jv1"Q +  
package NetFox; bsmZR(EnU  
import java.io.*; Cz+`C9#  
X) owj7U;  
NJI-8qTGI  
public class FileAccessI implements Serializable{ q#xoM1  
GASDkVoij  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $GSn#} yz  
RandomAccessFile oSavedFile; ^Cst4=:W  
long nPos; !.?2zp~  
quTM|>=_R  
& VJ+X|Z  
public FileAccessI() throws IOException [W ,Ej  
{ i ?%;s5<  
this("",0); d!D#:l3;  
} >KNiMW^V  
]t=m  
LS}u6\(  
public FileAccessI(String sName,long nPos) throws IOException 5hr$tkk L  
{ L09YA  
oSavedFile = new RandomAccessFile(sName,"rw"); ||;V5iR:  
this.nPos = nPos; 0>6J -   
oSavedFile.seek(nPos); @a'Rn  
} P6!c-\  
[o<Rgq 4  
dzjp,c@  
public synchronized int write(byte[] b,int nStart,int nLen) \'xF\V  
{ /vYuwaWG=  
int n = -1; l:-$ulAx  
try{ 3,8<5)ds*  
oSavedFile.write(b,nStart,nLen); ]]Sz|6P  
n = nLen; %?Yf!)owh  
} w<!F& kQB  
catch(IOException e) V8@VR`!'  
{ fZw/kjx@  
e.printStackTrace (); p9 <XaJ}   
} 1Mn=m w  
DI{VJ&n66  
E z?O gE{  
return n; I q]+O Q  
} -y|>#`T/  
)"/.2S;  
v-B{7 ~=#Z  
} mSm:>hBd  
U>H"N1  
r7+"i9  
/* F0t-b%w,  
**SiteInfoBean.java I<L  
*/ Y``50{7  
package NetFox; xAbx.\  
uD0T()J.P5  
e{EKM4  
public class SiteInfoBean { w j !YYBH  
A=JPmsj.  
{$-lXw4  
private String sSiteURL; //Site's URL (HbA?Aja  
private String sFilePath; //Saved File's Path 9AF%Y:y  
private String sFileName; //Saved File's Name S~()A*5  
private int nSplitter; //Count of Splited Downloading File :[xFp}w{  
uH="l.u  
F$.h+v   
public SiteInfoBean() Rsd~t_a1  
{//nSplitter的缺省值为5 |(u6xPs;P  
//default value of nSplitter is 5 <|8N\FU{  
this("","","",5); 1Bp?HyCR  
} q4=Gj`\43  
*eL&fC  
@rI+.X  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) NXo$rf:  
{ 4zKmoYt  
sSiteURL= sURL; hGh91c;4  
sFilePath = sPath; OIJNOuI  
sFileName = sName; eocq Hwbv  
this.nSplitter = nSpiltter; ;}1O\nngR  
/|Z_Dy  
) rw!. )  
} xs,,)jF(u  
CoZOKRoaH  
o]/*YaB2>  
public String getSSiteURL() >n$V1U&/  
{ ^x2zMB\t  
return sSiteURL; NH9"89]E  
} 3MX&%_wUhB  
n x4:n@J  
U/}YpLgdD  
public void setSSiteURL(String value) 0OCmyy  
{ PtsQV!  
sSiteURL = value; RGEgYOO  
} +*uaB  
9UDanj P  
\.ukZqB3 0  
public String getSFilePath() f|f)Kys%5  
{ W%@r   
return sFilePath; eF-U 1ZJT  
} R&.mNji*  
fVf @Ngvu  
|2ImitN0  
public void setSFilePath(String value) ['m7Wry  
{ $,u>,  
sFilePath = value; *!oV?N[eA'  
} Yo%ph%e  
HpP82X xj  
&?g!)O  
public String getSFileName() ;P *`v  
{ mHe[ NkY6  
return sFileName; ba-4V8w  
} !E7JDk''@  
U45kA\[bZ  
FD'yT8]"  
public void setSFileName(String value) cl04fqX  
{ gcF:/@:Rm  
sFileName = value; Upw`|$1S  
} 9]C%2!Ur,  
B/O0 ~y!n  
"w&IO}j;=  
public int getNSplitter() Oh# z zo  
{ |xawguJ  
return nSplitter; )_n=it$  
} &cGa~#-u  
?}RPn f  
+>3jMs~&  
public void setNSplitter(int nCount) [s4|+  
{ tn{YIp   
nSplitter = nCount; :a/l9 m(  
} O NVhB  
} y%Rq6P=4Q  
hsB3zqotF  
`%A vn<  
/* ]A%]W^G  
**Utility.java fn#qcZv?  
*/ mUj_V#v  
package NetFox; PctXh, =  
"7q!u,u  
P{,A%t  
public class Utility { E)%D LZ  
+pPfvE`  
ee/3=/H|;  
public Utility() `^ZhxFX  
{ Um^4[rl:#g  
9;7Gzr6A"  
O!!N@Q2g  
} '8Cg2v5&w  
=kTHfdin&  
//线程睡眠 qxB|*P `  
public static void sleep(int nSecond) gLm,;'h%u  
{ x8w l  
try{ 2##;[  
Thread.sleep(nSecond); *8r^!(Kj  
} f$76p!pDa  
catch(Exception e) Vy=P*  
{ 3n,jrX75u  
e.printStackTrace (); cO$xT;kK  
} |k$6"dXSO  
} P!Brw72  
)SZzA'  
//日志 QLH!>9Ch  
public static void log(String sMsg) !RP0W  
{ \o*w#e[M  
System.err.println(sMsg); qjObu\r  
} q68CU~i*  
U&i#cF   
oam$9 q  
public static void log(int sMsg) yg.o?eML  
{ ~&?57Sw*m  
System.err.println(sMsg); X J`*dgJ  
} Xdi<V_!BC-  
} qV9}N-sS  
$PG(>1e  
\ZM5J  
/* v w 6$v  
**TestMethod.java cLEd -{x  
*/ -4[eZ>$A|  
package NetFox; 4E2#krE%  
(gnN </%  
Atb`Q'Yrw  
public class TestMethod { K@<*m!%<2  
_TLspqi  
Nw9@E R  
public TestMethod() E[WU  
{ ///xx/weblogic60b2_win.exe #.rkvoB0N  
try{ kebk f,`p  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); W[I$([  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); i=L 86Ks  
SiteFileFetch fileFetch = new SiteFileFetch(bean); x <a}*8"  
fileFetch.start(); I{ Ip  
} : tBe/(e4#  
catch(Exception e){e.printStackTrace ();} )RN3Oz@H  
0cSm^a  
vh.-9eD  
} Zb=;\l*&  
MJh.)kd$  
_CPj] m{  
public static void main(String[] args) cRH(@b Xr  
{ sj4\lpZ3h  
new TestMethod(); L pq)TE#  
} 43E)ltR=]  
} `*cqT  
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