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http断点续传简单实现(java)

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/* N$N 7aE$  
**SiteFileFetch.java ; ,n}>iTE  
*/ ;a 6Z=LB  
package NetFox; xSrjN  
import java.io.*; 9m%2&fjK^  
import java.net.*; P&IS$FC.\  
sB8v:  
-% \LW1  
public class SiteFileFetch extends Thread { ?7uK:'8  
Fv<3VKueK[  
'U-8w@\Z  
SiteInfoBean siteInfoBean = null; //文件信息Bean '*D>/hn|:]  
long[] nStartPos; //开始位置 4JRQ=T|P7I  
long[] nEndPos; //结束位置 B?l 0u  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ipyc(u6Z5  
long nFileLength; //文件长度 L~Y^O`c  
boolean bFirst = true; //是否第一次取文件 |3mcL'  
boolean bStop = false; //停止标志 9[R+m3V/`  
File tmpFile; //文件下载的临时信息 q $PO. #  
DataOutputStream output; //输出到文件的输出流 RFPcH8-u7  
7%Ou6P$^fr  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) L7[f-cK2:  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7(d#zu6n  
{ ^l<!:SS  
siteInfoBean = bean; ZCuoYE$g  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); E24j(>   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); re4A5Ev$  
if(tmpFile.exists ()) s|I$c;>  
{ *7w!~mn[m  
bFirst = false; ~G1B}c]  
read_nPos(); a7!{`fR5  
} Xk!wT2;  
else +j %y#_~  
{ :D4'x{#H  
nStartPos = new long[bean.getNSplitter()]; P *&Cght>0  
nEndPos = new long[bean.getNSplitter()]; R90#T6^  
} ^*w}+tB  
gJ~CD1`O  
Z/T( 4  
kj6H+@ {  
} Lrmhr3 w5  
X]o"4#CQIX  
z;MPp#Y  
public void run() ZL:SJ,C  
{ zI\+]U'  
//获得文件长度 jYvl-2A'  
//分割文件 ?C- ju8]|  
//实例FileSplitterFetch m2P&DdN[  
//启动FileSplitterFetch线程 =sAU5Ag68  
//等待子线程返回 t1G__5wp  
try{ |>OBpb  
if(bFirst) 9s*QHCB0  
{ zXU g(xu  
nFileLength = getFileSize(); @AM11v\:  
if(nFileLength == -1) " %qr*|  
{ r Nurzag  
System.err.println("File Length is not known!"); ns *:mGh  
} ^!x! F  
else if(nFileLength == -2) u:Ye`]~o  
{ R1/c@HQw?  
System.err.println("File is not access!"); c&N;r|N  
} R>]7l!3^1  
else K|l}+:k  
{ VN (*m(b  
for(int i=0;i<nStartPos.length;i++) bWSc&/ 9y  
{ R7K`9 c1f6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^d@2Y0hH  
} jD%|@ux  
for(int i=0;i<nEndPos.length-1;i++) g"k4Z  
{ KVh#"]<WV  
nEndPos = nStartPos[i+1]; TZ `Ypi7r  
} ~Uey'Xz  
nEndPos[nEndPos.length-1] = nFileLength; ^G2M4+W|  
} !tcz_%  
} 5Zd oem  
ecQ{ePoU  
'2hy%  
//启动子线程 >*opEI+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .9WOT ti  
for(int i=0;i<nStartPos.length;i++) 5!cp^[rGL  
{ TUz4-Pd  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j7QK8O$XL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /!^,+  
nStartPos,nEndPos,i); [ZC\8tP`V  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); MBU|<tc  
fileSplitterFetch.start(); 0[M2LF!m  
} 2K{'F1"RM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {I0U 4]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); UP$>,05z6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Yh!=mW!OY  
nEndPos = " + nFileLength); %p$XK(6  
// fileSplitterFetch[nPos.length-1].start(); X 6tJ  
M:/(~X{?  
M. % p'^5  
//等待子线程结束  }( CYok  
//int count = 0; M_Q`9  
//是否结束while循环 hc[J,yG  
boolean breakWhile = false; c*.  
Q{?\qCrrYl  
Bpm COA  
while(!bStop) FU/:'/ L  
{ 'W4B  
write_nPos(); :aomDK*  
Utility.sleep(500); D!! B4zt  
breakWhile = true; ?bt;i>O\  
j6RV{Lkr_  
@&`^#pok  
for(int i=0;i<nStartPos.length;i++) }/&Zo=Q$  
{ sS;)d  
if(!fileSplitterFetch.bDownOver) DbLo{mFEIj  
{ yP"}(!~m  
breakWhile = false; q~ Z UtF  
break; $[?N^   
} U5wh( vi  
} m"/..&'GC  
if(breakWhile) }4!}vkVx  
break; !-^oU"  
.\T!oSb4[  
6vAZLNG3  
//count++; m(MQ  
//if(count>4) 3N- '{c6]U  
// siteStop(); NfPWcK [  
} Z!~_#_Ugl  
!;h&@LXG(  
VgIk'.  
System.err.println("文件下载结束!"); M1Ff ,]w  
} |8~)3P k  
catch(Exception e){e.printStackTrace ();} xWXLk )A  
} C]8w[)d[`;  
9xz@2b@  
(}6\_k[}m  
//获得文件长度 ut\ X{.r7  
public long getFileSize() @@U  
{ ukEJD3i  
int nFileLength = -1; ><D2of|  
try{ f4\$<g/~  
URL url = new URL(siteInfoBean.getSSiteURL());  8Cp@k=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0Zwx3[bq6K  
httpConnection.setRequestProperty("User-Agent","NetFox"); M0xhcU_  
4]tg!ks  
; 8DtnnE  
int responseCode=httpConnection.getResponseCode(); h[iO'Vq  
if(responseCode>=400) ^gx~{9`RR  
{ n/(}|xYU  
processErrorCode(responseCode); 3%(r,AD  
return -2; //-2 represent access is error aWJ BYw6{L  
} aV|V C $  
+@!\3a4!  
zEO~mJzo  
String sHeader; hx&fV#m  
#~/9cVm$  
*9r(lmrfj  
for(int i=1;;i++) [zN*P$U]  
{ %.f%Q?P  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2;"vF9WMm  
//Utility.log(in.readLine()); lMu9Dp  
sHeader=httpConnection.getHeaderFieldKey(i); [<U=)!Swg  
if(sHeader!=null) R[l`# I  
{ ^j${#Q  
if(sHeader.equals("Content-Length")) $dKfUlO  
{ 2HBey  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #tHYCSr]  
break; IoJI|lP  
} zLe(#8G  
} +u=VO#IA#  
else .hxFFk%5  
break; ?'a>?al%>  
} \.iejB  
} 1 +-Go}I  
catch(IOException e){e.printStackTrace ();} hy;V~J#  
catch(Exception e){e.printStackTrace ();} &F :.V$  
Ru#pJb(R  
=J)-#|eZG  
Utility.log(nFileLength); V6d,}Z+"z'  
zL}`7*d:v  
l3^'bp6HQ  
return nFileLength; $PRd'YdL/  
} Q~ Ad{yC  
{aV,h@>  
e<=Nd,v4;  
//保存下载信息(文件指针位置) `u_MdB}<x;  
private void write_nPos() TAOsg0  
{ VhLfSN>W  
try{ Ws0)B8y,|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); LqI&1$#  
output.writeInt(nStartPos.length); Ws2?sn#x  
for(int i=0;i<nStartPos.length;i++) |P& \C8h  
{ u@:[ dbJ  
// output.writeLong(nPos); 73S N\  
output.writeLong(fileSplitterFetch.nStartPos); @N<h`vDa  
output.writeLong(fileSplitterFetch.nEndPos); n05GM.|*s  
} #+_=(J  
output.close(); o-&0_Zq_  
} l44QB8 9  
catch(IOException e){e.printStackTrace ();} tj*0Y-F~  
catch(Exception e){e.printStackTrace ();} Iy;"ht6  
} ?5B?P:=kl  
|N6.:K[`  
t OJyj49^a  
//读取保存的下载信息(文件指针位置) 7Q Ns q  
private void read_nPos() vN_ 8qzWk  
{ ; }T+ImjA  
try{ H{i|?a)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); RS&BS;  
int nCount = input.readInt(); UEx<;P8rP  
nStartPos = new long[nCount]; xj8z*fC;  
nEndPos = new long[nCount]; &M3KJ I0L  
for(int i=0;i<nStartPos.length;i++) #1*7eANfr  
{ w8$> 2  
nStartPos = input.readLong(); jy>?+hm?  
nEndPos = input.readLong(); 9(!AKKrr;  
} 0k5uqGLXe  
input.close(); 8EdaxeDq  
} x3U>5F@  
catch(IOException e){e.printStackTrace ();} >/ A'G  
catch(Exception e){e.printStackTrace ();} `x>6Wk1  
} Pe\Obd8d  
/joY? T  
,G="wI  
private void processErrorCode(int nErrorCode) z6B#F<h  
{ o-l-Z|)7  
System.err.println("Error Code : " + nErrorCode); 1 \aTA,  
} (@!K tW  
PP!-*~F0Jr  
y4IQa.F  
//停止文件下载 ?GhMGpd Mq  
public void siteStop() 0m> 8  
{ N`?/kubD  
bStop = true; +zLw%WD[l  
for(int i=0;i<nStartPos.length;i++) #6D>e~>n  
fileSplitterFetch.splitterStop(); !m-`~3P#l,  
xw_)~Y%\  
FAM:; F30  
} -Edy ~;_  
} 2&]LZ:(  
//负责部分文件的抓取 6`7bk35B  
**FileSplitterFetch.java ' i5KRFy-  
*/ T!41[vm(  
package NetFox; 2.MUQ;OX  
.b<W*4{j0H  
T2azHo7  
import java.io.*; &?1^/]'"r  
import java.net.*; Piwox1T ;  
&)||~  
I"3C/ pU2  
public class FileSplitterFetch extends Thread { VMJaL}J]  
ybFxz  
>!']w{G  
String sURL; //File URL +'olC^?5 }  
long nStartPos; //File Snippet Start Position SRk!HuXh  
long nEndPos; //File Snippet End Position $Q'z9ghEg  
int nThreadID; //Thread's ID +0Q +0:  
boolean bDownOver = false; //Downing is over vbtZ5Gm  
boolean bStop = false; //Stop identical pO:]3qv  
FileAccessI fileAccessI = null; //File Access interface z;<~j=lP  
Pz:,de~5Qm  
G![4K#~NM  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException uG6.(A1LM  
{ 2?Jw0Wq5D  
this.sURL = sURL; </xf4.C  
this.nStartPos = nStart; o'(BL:8s  
this.nEndPos = nEnd; q6nRk~  
nThreadID = id; ?{`7W>G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +By'6?22  
} oxL<\4)WJ  
5n}<V-yJ*m  
vo*oCfm  
public void run() H7;, Kr  
{ DQXcf*R  
while(nStartPos < nEndPos && !bStop) "qR, V9\  
{ ,&M#[>\(3  
{GnZ@Q:F  
. o /uA  
try{ vBF9!6X.  
URL url = new URL(sURL); `<>QKpAn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *xsBFCRU  
httpConnection.setRequestProperty("User-Agent","NetFox"); L;j++^p  
String sProperty = "bytes="+nStartPos+"-"; R*lq7n9  
httpConnection.setRequestProperty("RANGE",sProperty); N AY3.e  
Utility.log(sProperty);  @,k5T51m  
Gvh"3|u ?z  
_&S#;ni\c  
InputStream input = httpConnection.getInputStream(); <anKw|  
//logResponseHead(httpConnection); h ka_Fo  
F5/,S   
W~D_+[P|_  
byte[] b = new byte[1024]; 457{9k  
int nRead; I%a-5f$0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xt,Qn460;  
{ Q#SQ@oUzD  
nStartPos += fileAccessI.write(b,0,nRead); ?-mOAHW0q  
//if(nThreadID == 1) SiX<tj#HH\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \#dacQ2E@  
} LAf#Rco4  
Sm4BZF~!B  
0: hv6Ge^  
Utility.log("Thread " + nThreadID + " is over!"); C,l,fT  
bDownOver = true; , %z HykP  
//nPos = fileAccessI.write (b,0,nRead); (M$>*O3SR  
} k"&o)*d  
catch(Exception e){e.printStackTrace ();} \b(&-=(  
} @g5y_G{SP  
} /ugyUpyg  
.06D_L"M  
~d]v{<3  
//打印回应的头信息 pl&nr7\  
public void logResponseHead(HttpURLConnection con) ~r8<|$;  
{ j;coPehB  
for(int i=1;;i++) 9_:"`)] 3B  
{ # lvt4a"P"  
String header=con.getHeaderFieldKey(i); ? F #&F  
if(header!=null) A3_p*n@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); eP>_CrJb  
Utility.log(header+" : "+con.getHeaderField(header)); k B]`py!  
else [C6ba{9 B  
break; 9!Mh (KtQ  
} ye$_=KARP  
} [%dsq`b#  
<5z!0m-G  
K}@rte  
public void splitterStop() g-d{"ZXd J  
{ d%'#-w'  
bStop = true; T@yQOD7  
} tp cB}HUv  
I{(!h90  
mk1R~4v  
} I&La0g_E  
/)_4QSz7  
hTn"/|_SW  
/* Pqya%j  
**FileAccess.java X#$ oV#  
*//文件访问(定位,写) @r*GGI!  
package NetFox; iLSUz j`  
import java.io.*; z U[pn)pe  
:wIA.1bK}  
U U_0@V<  
public class FileAccessI implements Serializable{ u9S*2'  
_r3Y$^!U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 n?r8ZDJ'  
RandomAccessFile oSavedFile; `S|F\mI ~  
long nPos; #0<pRDXj  
(]'wQ4iQ  
)?[7}(4jI  
public FileAccessI() throws IOException <h/q^|tZ{  
{ {"Sv~L|J;  
this("",0); o!UB x<4  
} I20~bW  
c.]QIIdK  
SnFyK5  
public FileAccessI(String sName,long nPos) throws IOException o4FHR+u<M  
{  <Y"RsW9  
oSavedFile = new RandomAccessFile(sName,"rw"); O oA!N-Q  
this.nPos = nPos; i_*yS+Z;  
oSavedFile.seek(nPos); =_k  
} 3 twA5)v  
a%`Yz"<lQ  
p4z4[=-:  
public synchronized int write(byte[] b,int nStart,int nLen) ;?HP/dZLz  
{  }cMkh  
int n = -1; [x{$f7CEh  
try{ G$Mf(S'f  
oSavedFile.write(b,nStart,nLen); yGtTD9j  
n = nLen; )KFxtM-  
} }TMO>eB'  
catch(IOException e) xwD`R *  
{ 'm*W<  
e.printStackTrace (); -hnNa A  
} n! 5(Z5=  
?=Ceo#Er  
#w|v.35%?  
return n; .\$A7DD+A  
} @* vVc`;  
4$VDJ  
=|AYT6z,  
} %( 7##f_  
5;KJ0N*-  
#:BkDidt2v  
/* 8zeeC eIU  
**SiteInfoBean.java ktfm  
*/ [r"Oi| 8I  
package NetFox; rVP\F{Q4Tr  
*CXc{{  
=M-=94  
public class SiteInfoBean { | U0s1f  
?u:`?(\  
u_NLgM7*  
private String sSiteURL; //Site's URL Y)/|C7~W  
private String sFilePath; //Saved File's Path G8vDy1`q6  
private String sFileName; //Saved File's Name =cV|o]  
private int nSplitter; //Count of Splited Downloading File  b}NNkM  
g(i6Uj~)  
GFLat  
public SiteInfoBean() ?l%4 P5  
{//nSplitter的缺省值为5 9NwUX h(:(  
//default value of nSplitter is 5 nxhlTf>3  
this("","","",5); P]n0L4c  
} 8>WA5:]v  
'i$. _Tx  
hO[_ _j8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ojz'p5d`>  
{ eEBNO*2  
sSiteURL= sURL; _fZec+oM  
sFilePath = sPath; b||usv[or  
sFileName = sName; 0<v5_ pB  
this.nSplitter = nSpiltter; +&)/dHbL`]  
?3K~4-!? /  
b?OA|JqX  
} >6yQuB  
F% a&|X  
!;8Y?c-D  
public String getSSiteURL() RuYIG?J=/  
{ ZqrS]i@$  
return sSiteURL; Q/3*65  
} \:Tq0|]Px  
A z@@0  
x[};x;[ZE  
public void setSSiteURL(String value) Nb:j]U  
{ ;UgwV/d  
sSiteURL = value; a]fFR~ OY  
} UfPB-EFl$D  
G{6@]72  
=(hBgNH  
public String getSFilePath() X@[5nyILf  
{ e0 y.J  
return sFilePath;  ij:a+T  
} 9Br+]F _i  
]tu OWR  
r4[=pfe25  
public void setSFilePath(String value) X=-=z5  
{ *JX$5bZsI  
sFilePath = value; `^{G`es  
} Z?xaXFm_  
tH;9"z# ~  
MkFWZ9c3  
public String getSFileName() A@|Z^T:  
{ 9~j"6wS  
return sFileName; A4(L47^  
} l opl  
:_i1gY)  
[dLc+h1{B  
public void setSFileName(String value) t)8c rX}P  
{ eD7\,}O  
sFileName = value; S+KKGi_e  
} XsJ`x  
fhZwYx&t  
0_je@p+$  
public int getNSplitter() jA?[*HB  
{ i| cA)  
return nSplitter; P\WHM(  
} #]+BIr`  
hb~d4J=S  
V9< E `C  
public void setNSplitter(int nCount) ,[p?u']yZz  
{ hU(  
nSplitter = nCount; < q(i(%  
} bZWR. </  
} E l.eK9L  
!V#*(_+n  
pvt/{  
/* R-n%3oh  
**Utility.java Kg2@]J9m  
*/ QP<P,Bi~  
package NetFox; |af<2(d  
p({|=+bl  
vr47PM2al  
public class Utility { ~qb?#IY]`  
E.$//P n|1  
05 6yhB  
public Utility() ]lJ#|zd8o  
{ /-<]v3J  
=#TQXm']Gi  
ocW`sE?EED  
} Rbm+V{EF&  
zXGI{P0O  
//线程睡眠 3S^Qo9S  
public static void sleep(int nSecond) c?xeBC1-  
{ 3s:)CXO  
try{ hhjsg?4uL  
Thread.sleep(nSecond); .*FlB>1jy  
} IP !zg|c,  
catch(Exception e) uTbMp~cYB  
{ $\4Or  
e.printStackTrace (); ~c1~) QzZ  
} ,,9vk\  
} 3kJSz-_M  
)Knsy  
//日志 #2.C$  
public static void log(String sMsg) z9#jXC#OdN  
{ 0Z%<H\Z  
System.err.println(sMsg); y;9K  
} . 55aY~We  
@iz S_I,  
a~tBgy+9  
public static void log(int sMsg) 4f0dc\$  
{ kr1^`>O5  
System.err.println(sMsg); yNx"Ey dk`  
} @qJv  
} +fIy eX  
&P8Q|A-u  
.fW`/BXE  
/* `+r5I5  
**TestMethod.java Z3T26Uk  
*/ yFP#z5G  
package NetFox; D3 E!jQ1  
VHws9)  
|@)ij c4i  
public class TestMethod { !lB,2_  
`V0]t_*D  
==j3 9  
public TestMethod() t! Av [K  
{ ///xx/weblogic60b2_win.exe BQ&h&57K  
try{ 9zd)[4%=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IPE(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 17qrBG-/MD  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9p$q@Bc  
fileFetch.start(); Bp6Evi  
} #wm)e)2@  
catch(Exception e){e.printStackTrace ();} ZNA?`Z)f  
Ap>n4~  
86} rz  
} aA yFu_  
Ip 1QmP  
n:!J3pR  
public static void main(String[] args) CC87<>V  
{ q{JD]A:  
new TestMethod();  3i$AR  
} {S&&X&A`v  
} 3 \WdA$Wx  
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