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http断点续传简单实现(java)

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/* i)=m7i  
**SiteFileFetch.java 18jJzYawh  
*/ 'gYg~=  
package NetFox; z23#G>I&  
import java.io.*; OH>r[,z0  
import java.net.*;  %W(^6p!  
nkTYWw  
(9E( Q*J5x  
public class SiteFileFetch extends Thread { / HL_$g<  
nMkOUW:T!  
{ yTpRQN~  
SiteInfoBean siteInfoBean = null; //文件信息Bean ~)_K"h.DY  
long[] nStartPos; //开始位置 2.ew^D#  
long[] nEndPos; //结束位置 :Pc(DfkS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3+ e4e  
long nFileLength; //文件长度 d<!IGt4Ky  
boolean bFirst = true; //是否第一次取文件 sp^Wo7&g  
boolean bStop = false; //停止标志 -ovoRI^6`}  
File tmpFile; //文件下载的临时信息 ea 2 `q  
DataOutputStream output; //输出到文件的输出流 p:Oz<P  
-'j7SOGk  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) hzv3F9.x  
public SiteFileFetch(SiteInfoBean bean) throws IOException N0nj`  
{ 0JK2%%  
siteInfoBean = bean; +N7"EROc  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); w\Iqzpikr  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); vf[&7n  
if(tmpFile.exists ())  ![ a  
{ dIvy!d2l  
bFirst = false; pp<E))&R  
read_nPos(); o OQ'*7_  
} ;>8kPG  
else vmLpm xS  
{ X~Cq  
nStartPos = new long[bean.getNSplitter()]; /p,{?~0mj  
nEndPos = new long[bean.getNSplitter()]; x7H A722w  
} ]W;:|/,c  
zz&vfO31J  
=PZWS& (L  
pcnl0o~  
} oXdel Ju?  
=MxpH+spI  
vTHq)C.7G  
public void run() !3@{U@*Z]  
{ VtWT{y5Ec  
//获得文件长度 _W}(!TKO  
//分割文件 ^zg acn  
//实例FileSplitterFetch TU%bOAKF\  
//启动FileSplitterFetch线程 "T7>)fbu  
//等待子线程返回 NZ+7p{&AN  
try{ sDX/zF6t  
if(bFirst) -R:X<eb  
{ "b`7[;a  
nFileLength = getFileSize(); ] opto  
if(nFileLength == -1) &atyDFJ'  
{ Q(e{~ ]*  
System.err.println("File Length is not known!"); O5M2`6|As  
} D#ZPq,f  
else if(nFileLength == -2) J0sGvj{  
{ YQYX,b  
System.err.println("File is not access!"); modC6d%  
} "W5rx8a  
else T<6GcI>A  
{ l#$TYJi  
for(int i=0;i<nStartPos.length;i++) *7Xzht&f  
{ z0 \N{rP&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Gc'M[9Mh  
} lH6fvz  
for(int i=0;i<nEndPos.length-1;i++) Y& 5.9 s@'  
{ YQ7@D]#  
nEndPos = nStartPos[i+1]; l sr?b  
} +(&|uq^  
nEndPos[nEndPos.length-1] = nFileLength; T pD;  
} *{|$FQnR>(  
} $ser+Jt=  
ceG&,a$\  
*QE"K2\5  
//启动子线程 *gDl~qNRoS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <h@]Ri  
for(int i=0;i<nStartPos.length;i++) ^Q\XGl  
{ G,|KL" H6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CdL.?^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ot }6D  
nStartPos,nEndPos,i); #q;z8 @  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |z*>ixK  
fileSplitterFetch.start(); 3ev -Iqz  
} (hN?:q?'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zSXA=   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ha)np  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $w/E9EJ)3A  
nEndPos = " + nFileLength); mX;H((  
// fileSplitterFetch[nPos.length-1].start(); Cfv]VQQE  
P#;Th8k{K2  
1'fb @vO  
//等待子线程结束 y42#n  
//int count = 0; Du!._  
//是否结束while循环 %K l(>{N  
boolean breakWhile = false; /[{auUxSX  
+GeWg` \=  
`*k@4.J{  
while(!bStop) 95L yYg  
{ \0&SI1Yp  
write_nPos(); jT-<IJh!o  
Utility.sleep(500); 9yL6W'B!  
breakWhile = true; " #v%36U  
oM-[B h]A  
OaaH$B  
for(int i=0;i<nStartPos.length;i++) D5L{T+}Oi%  
{ i*CnoQH  
if(!fileSplitterFetch.bDownOver) 5\'AD^{  
{ d.AC%&W  
breakWhile = false; esI'"hVJ  
break; 7&|6KN}c  
} <u0,Fp  
} 4K7{f+T  
if(breakWhile) cz(G]{N  
break; 2Wl{Br.  
wE6A 7\k%  
328L)BmW  
//count++; oKa>.e7.  
//if(count>4) }#/l N  
// siteStop(); H=<LutnZ  
} F#|Z# Mu  
RRzP* A%=  
hB>^'6h+  
System.err.println("文件下载结束!"); T 1zi0fa'  
} H1&RI4XC  
catch(Exception e){e.printStackTrace ();} [.-a$J[4+F  
} a g;dc  
FN\GE\H  
pkk4h2Ah  
//获得文件长度 "dtlME{Bx  
public long getFileSize() (a#pvEY  
{ 0Oap39  
int nFileLength = -1; Y;_T=  L  
try{ -Qb0:]sV#  
URL url = new URL(siteInfoBean.getSSiteURL()); >lLo4M 3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $[z<oN_Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); Yqj+hC6>,  
<5IQc[3]aP  
(Ilsk{aB;A  
int responseCode=httpConnection.getResponseCode(); bVK$.*,  
if(responseCode>=400)  }_%P6  
{ ir&.Z5=  
processErrorCode(responseCode); "DpKrVuG  
return -2; //-2 represent access is error yU_9a[$V  
} L~&" aF/b  
,LUTHWEo"I  
7I >J$"  
String sHeader; @i1q]0  
gtYRV*^q  
"8/dD]=f^a  
for(int i=1;;i++) !y*oF{RZ  
{ U^?= 0+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J?D\$u:  
//Utility.log(in.readLine()); 1;&T^Gdj  
sHeader=httpConnection.getHeaderFieldKey(i); tX?J@+  
if(sHeader!=null) e U;jP]FA  
{ XwPx9+b6j  
if(sHeader.equals("Content-Length")) 8Q(8b@ZO,  
{ P {H{UKs#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Le@? /  
break; 3.),bm  
} 4f {+pf^R  
} c0[k T  
else 6Xa.0(h  
break; ^73=7PZ  
} ~:Mm<*lL%  
} }N,>A-P  
catch(IOException e){e.printStackTrace ();} e{!vNJ0`  
catch(Exception e){e.printStackTrace ();} VMHC/jlX@r  
;J=:IEk  
R|Y~u*D  
Utility.log(nFileLength); :-Wv>V\t  
8&.-]{Z  
7>,rvW:]  
return nFileLength; 1VLLo~L%  
} .'lN4x  
&HL{LnLP@/  
Ef,Cd[]b  
//保存下载信息(文件指针位置) >FF1)~  
private void write_nPos() [h HG .  
{ jVYH;B%%z  
try{ .$wLLE^*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hk;bk?:m  
output.writeInt(nStartPos.length); *h:kmT  
for(int i=0;i<nStartPos.length;i++) 3_zSp.E\l  
{ D9o*8h2$  
// output.writeLong(nPos); :Tb7r6  
output.writeLong(fileSplitterFetch.nStartPos); _6rKC*Pe1  
output.writeLong(fileSplitterFetch.nEndPos); bU+9Gi@v  
} h=[-Er'B  
output.close(); xa#gWIP*  
} QJSr:dP4dG  
catch(IOException e){e.printStackTrace ();} (\vXA4Oa,  
catch(Exception e){e.printStackTrace ();} } yq  
} euZ I`*0  
^'W%X  
x+^Vg3 q  
//读取保存的下载信息(文件指针位置) 4_Y!elH)  
private void read_nPos() 5;Ia$lm=y  
{ N-QCfDao  
try{ `~nCbUUee  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =]b9X7}  
int nCount = input.readInt(); 61:9(*4~!F  
nStartPos = new long[nCount]; C3.=GRg~l  
nEndPos = new long[nCount]; }n[Bq#  
for(int i=0;i<nStartPos.length;i++) , ` o+ ?  
{ U~/ID  
nStartPos = input.readLong(); kl<g;3  
nEndPos = input.readLong(); ) ,Npv3(  
} ?Aw3lH#:  
input.close(); 0N5bPb  
} !Uy>eji}  
catch(IOException e){e.printStackTrace ();} e1 ^l.>2d6  
catch(Exception e){e.printStackTrace ();} uV77E*+7\  
} c&e0OV\m  
^Y 7U1I  
ZNL5({lv  
private void processErrorCode(int nErrorCode) s=U\_koyH  
{ ke6n/ h5`  
System.err.println("Error Code : " + nErrorCode); g;G5 r&T  
} Q|//Z  
;)|nkI  
!*bdG(pK  
//停止文件下载 oHsP?%U  
public void siteStop() `M]BhW)  
{ PL@7 KD Q  
bStop = true; 2sun=3qb  
for(int i=0;i<nStartPos.length;i++) NCDxcz;Gb  
fileSplitterFetch.splitterStop(); D|TR!  
b1)\Zi  
v, 0<9!'v  
} 7d9Z/J@>  
} (hsZ  
//负责部分文件的抓取 0WXVc  
**FileSplitterFetch.java **HrWM%?8o  
*/ E9R]sXf8  
package NetFox; L*^ V5^-  
iT$d;5_pU  
vZk9gGjk  
import java.io.*; `^e*T'UPl  
import java.net.*; Wr#~GFg  
?(Bl~?zD  
3+zzi  
public class FileSplitterFetch extends Thread { 9b%j.Q-W  
Tk](eQsy.v  
PUKVn+h  
String sURL; //File URL d?}hCo=/Xq  
long nStartPos; //File Snippet Start Position #ovM(Mld  
long nEndPos; //File Snippet End Position ;@4sd%L8V  
int nThreadID; //Thread's ID UN(3i(d  
boolean bDownOver = false; //Downing is over )Ga8`t"  
boolean bStop = false; //Stop identical PW)8aLU  
FileAccessI fileAccessI = null; //File Access interface =mLeMk/7 w  
.hne)K%={y  
hgwn> p:S#  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException oG\>--  
{ ^'Y HJEK  
this.sURL = sURL; r0uJ$/!  
this.nStartPos = nStart; |0]YA  
this.nEndPos = nEnd; 1tyNRoET  
nThreadID = id; rXDJ:NP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;-Ado8  
} `u=oeM :  
Wl TpX`  
WG\Q5k4Ba  
public void run() 07Y_^d  
{ X TM$a9)  
while(nStartPos < nEndPos && !bStop) nF|Oy0  
{ 4 +I 3+a"  
<M305BH  
B G5X_s0/  
try{ "$P'Wv  
URL url = new URL(sURL); %2YN,a4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v^\JWPR/  
httpConnection.setRequestProperty("User-Agent","NetFox"); DZ2Fl>7  
String sProperty = "bytes="+nStartPos+"-"; '}CN?f|.  
httpConnection.setRequestProperty("RANGE",sProperty); 4v>o%  
Utility.log(sProperty); 1 yJ75/  
SdSgn|S  
bq: [Nj  
InputStream input = httpConnection.getInputStream(); ,zoB0([  
//logResponseHead(httpConnection); I}_;A<U  
/} a_8iM\  
0}D-KvjyP  
byte[] b = new byte[1024]; 4uPH  
int nRead; H7}g!n?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L9$&-A9ix  
{ T?#s'd  
nStartPos += fileAccessI.write(b,0,nRead); nfa_8  
//if(nThreadID == 1) '(TmV#3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?N`qLGRm  
} cB<O.@  
|zh +  
|+u+)C  
Utility.log("Thread " + nThreadID + " is over!"); ot0U-G(  
bDownOver = true; ovbEmb  
//nPos = fileAccessI.write (b,0,nRead); +\srZ<67  
} 3jXR"@Z-  
catch(Exception e){e.printStackTrace ();} L7<+LA)s0  
} e|JIrOnc  
} e) ]RA?bF  
pbPz$Y  
G~S))p  
//打印回应的头信息 }\DAg'e)  
public void logResponseHead(HttpURLConnection con) ,!r@9T  
{ *|^,DGfQ6  
for(int i=1;;i++) ;}UzJe ,S  
{ L,WkJe3  
String header=con.getHeaderFieldKey(i); gU+ss  
if(header!=null) 1z3]PA!R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \FVNXU MU  
Utility.log(header+" : "+con.getHeaderField(header)); B#QL M^  
else b]"2 VN  
break; }#&~w 0P  
} sbgJw  
} ~};]k}  
)=y.^@UT@  
$,.3&zsy  
public void splitterStop() O/(3 87=U  
{ k{_1r;  
bStop = true; 0u>yT?jP  
} +)?,{eE|  
)dqR<)  
c5<kbe  
} 7&h\l6}Yh  
hN[X 1*  
*B %y`cj|  
/* zf`5>h|  
**FileAccess.java - Sx0qi'%  
*//文件访问(定位,写) 1]Gf)|  
package NetFox; o T:j:n  
import java.io.*; 1k$2LQ  
eU`;L [  
q)NXyy4BT  
public class FileAccessI implements Serializable{ -!@H["  
jiqi!*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 WUzS lZq  
RandomAccessFile oSavedFile; hK Fk$A  
long nPos; bAN10U  
mlD%d!.  
15o9CaQw4"  
public FileAccessI() throws IOException :DDO=  
{ y:~eU  
this("",0); ,|6Y\L  
} oN_S}o  
#,t2*tM  
u$apH{  
public FileAccessI(String sName,long nPos) throws IOException %B[YtWqm`/  
{ :wFb5"  
oSavedFile = new RandomAccessFile(sName,"rw"); fdN45in=>  
this.nPos = nPos; "&@gX_%  
oSavedFile.seek(nPos); j[_t6Z  
} dUI3erO  
Rk}\)r\  
mluW=fE  
public synchronized int write(byte[] b,int nStart,int nLen) p 7 , f6kG  
{ 3gC\{y!8  
int n = -1; C\y[&egww  
try{ 2=jd;2~  
oSavedFile.write(b,nStart,nLen); kZJt ~}  
n = nLen; eH ;Wfs2f  
} o^8*aH)I>Y  
catch(IOException e) 4 U3C~J  
{ Tw2Xe S  
e.printStackTrace (); =g/4{IL%  
} :8](&B68gE  
@m5O{[euj<  
bjuYA/w<  
return n; r5D jCV"  
} <9=zP/Q  
X'YfjbGo  
n>u.3w L  
} wYZy e^7  
W/b"a?wE{  
s.f`.o  
/* d&/^34gn  
**SiteInfoBean.java )C'G2RV  
*/ ` 52% XI  
package NetFox; =9kj? u~  
]\[m=0K  
jn.R.}TT  
public class SiteInfoBean { d1UVvyH  
P h9Hg'  
oxUE79  
private String sSiteURL; //Site's URL &r&;<Q  
private String sFilePath; //Saved File's Path V*~1,6N [  
private String sFileName; //Saved File's Name ,h3269$J  
private int nSplitter; //Count of Splited Downloading File J@oEV=L  
jVLY!7Z4  
='7er.~\  
public SiteInfoBean() K#_~ !C4L  
{//nSplitter的缺省值为5 :&xz5c`"04  
//default value of nSplitter is 5 83mlZ1jQz  
this("","","",5); 6\; 4 4,3  
} ;M%oQ> ].[  
u)<Ysx8G  
N!tpzHXw  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jjJc1p0  
{ $KoPGgC[  
sSiteURL= sURL; lc\>DH\n6  
sFilePath = sPath; ;n% ]*v  
sFileName = sName; TX< e_[$\  
this.nSplitter = nSpiltter; ;b, -$A  
2z'+1+B'  
/X(@|tk:  
} 1"8Z y6t  
N BV}4  
*ah>-}-  
public String getSSiteURL() v_y!Oh?EG  
{ ^L>MZA ?  
return sSiteURL; #Tr;JAzVjG  
} ygmv_YLjm  
k! J4Z ${k  
eXj\DjttG}  
public void setSSiteURL(String value) CBiU#h q  
{ 0_YxZS\  
sSiteURL = value; BP)q6?Mz  
} 9oZ } h&  
@5{.K/s  
1Z^`l6|2  
public String getSFilePath() 4M;sD;3  
{ J!21`M-Ue  
return sFilePath; i /O1vU#  
} [W^6u7~  
Y|{r vBKjf  
-ET*M<  
public void setSFilePath(String value) $=e&q  
{ u=p ;A1oy  
sFilePath = value; ]_^"|RJ  
} aukk|/3Ih  
w.4u=e >Z4  
\zk?$'d  
public String getSFileName() :FX'[7;p  
{ +-Z"H)  
return sFileName; ,pQ'w7  
} MgJ%26TZ  
3a'Rs{qxn  
h(C#\{V  
public void setSFileName(String value) :z izca4  
{ =]_d pEEQ  
sFileName = value; mQwk!* U  
} viW~'}^k7  
"D ts*  
Wrf^O2  
public int getNSplitter() _&k'j)rg  
{ 4A\BGD*5  
return nSplitter; U^E  
} p9FA_(`^  
)LXoey!aZ  
v`[Tl  
public void setNSplitter(int nCount) %v?jG(o  
{ AijPN  
nSplitter = nCount; "E@NZ*"u  
} [ 4?cM\_u@  
} Uv @!i0W  
9%p7B~}E  
O:oU`vE  
/* .u&&H_ UmE  
**Utility.java d1srV`  
*/ "_ PH"W  
package NetFox; !SLP8|Cd  
^@|<'g.R-  
>< <$  
public class Utility { <GL}1W"Ay  
ql#{=oGDnA  
>,w\lf9  
public Utility() ?6gDbE%  
{ !(MA5L-  
Z^/z  
1S*8v 7  
} w>NZRP_3  
?/`C~e<J  
//线程睡眠 R`Ys;g/!  
public static void sleep(int nSecond) <;$Sa's,LE  
{ ,_"7|z wb  
try{ ~6@c]:  
Thread.sleep(nSecond); D-TNFYYy2  
} 1=9qAp;?o  
catch(Exception e) ! /|0:QQi  
{ #hy5c,}>  
e.printStackTrace (); ugIm:bg&  
} 38x[Ad4%  
} _Ep{|]:gw  
xWenKY,  
//日志 }AMYU>YE=  
public static void log(String sMsg) }<5\O*kX4  
{ yBYuDfeZ  
System.err.println(sMsg); Xhq? 7P$3  
} 7`uA  
X <ba|(  
7.lK$J:  
public static void log(int sMsg) 8 7|8eU2:k  
{ O" X!S_R  
System.err.println(sMsg); c"f-$^<  
} 7(A G]  
} I&'S2=s  
KV^:sxU  
^-e3=&  
/* ~WYE"(  
**TestMethod.java 75hFyh;u  
*/ .v #0cQX+.  
package NetFox; 8T>3@kF  
y]QQvCJr3d  
|*]X\UE  
public class TestMethod { ,%)WT>  
&;NNU T>Q  
d!}jdt5%  
public TestMethod() xVHQ[I%  
{ ///xx/weblogic60b2_win.exe eu}:Wg2  
try{ i h`y0(<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7)8rc(58  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); np'M4^E;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w{YtTZp3  
fileFetch.start(); ;H m-,W  
} &geOFe}R  
catch(Exception e){e.printStackTrace ();} 5H'b4Cyi`  
(04j4teE  
Ru9pb~K  
} m5'__<  
2kp|zX(  
:uT fhr  
public static void main(String[] args) T_(e(5  
{ Fu1|b2B-x  
new TestMethod(); XqE55Jclp  
} TeGLAt  
} 6bRQL}[  
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