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http断点续传简单实现(java)

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/* \/ ipYc  
**SiteFileFetch.java )Z)Gb~G  
*/ Ub/ZzAwq  
package NetFox; |-L7qZu%  
import java.io.*; ^h^.;Iqr=  
import java.net.*; in6*3C4  
(e Ssx/  
HoK+g_9~  
public class SiteFileFetch extends Thread { ]kd:p*U6P  
p<3<Zk 7~0  
aa" 3 Io  
SiteInfoBean siteInfoBean = null; //文件信息Bean A9;,y'm^8  
long[] nStartPos; //开始位置 $O%"[w  
long[] nEndPos; //结束位置 DTG-R>y^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Jj?HOtaM  
long nFileLength; //文件长度 Q-z `rW  
boolean bFirst = true; //是否第一次取文件 :W;eW%Y  
boolean bStop = false; //停止标志 ;Y0M]pC  
File tmpFile; //文件下载的临时信息 W4UK?#S+  
DataOutputStream output; //输出到文件的输出流 {@6:kkd  
sNM ]bei  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) t&Q(8Hz  
public SiteFileFetch(SiteInfoBean bean) throws IOException No`*->R  
{ Tl2(%qB  
siteInfoBean = bean; =#=}|Q}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5?Pf#kq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @)U;hk)j;  
if(tmpFile.exists ()) F?[1 m2  
{ )FNn  
bFirst = false;  TD%&9$F  
read_nPos(); )Xa_ry7  
} Em !%3C1r  
else u`D _  
{ 4}s'xMT!  
nStartPos = new long[bean.getNSplitter()]; YxrMr9>l1  
nEndPos = new long[bean.getNSplitter()]; ` FOCX;  
} 4XAs^>N+  
"blq)qo)  
lV$CBS  
t<ZBp0  
} ==Xy'n9'  
Q-rG~O9-  
Qj|rNeM_  
public void run() \Y>b#*m(4  
{ D<|$ZuB4  
//获得文件长度 b3FKDm[  
//分割文件 R:$E'PSx  
//实例FileSplitterFetch C+g}+  
//启动FileSplitterFetch线程 ~(8fUob  
//等待子线程返回 >lKu[nq;  
try{ 8&M<?oe  
if(bFirst) E- [Eg  
{ V:>r6  
nFileLength = getFileSize(); 0N~kq-6.\  
if(nFileLength == -1) X</Sl>[8  
{ ul#y'iY]  
System.err.println("File Length is not known!"); y0`; br\X  
} ;0Q" [[J  
else if(nFileLength == -2) ,n[<[tkCR  
{ x;<0Gg~jB  
System.err.println("File is not access!"); NyT%S?@y<  
} @HPr;m!  
else heL`"Y2'y>  
{ IT{c:jo1{`  
for(int i=0;i<nStartPos.length;i++) PpKjjA<  
{ 0|.jIix;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^b$_I31D  
} (qvH=VTwP  
for(int i=0;i<nEndPos.length-1;i++) jXLd#6  
{ o$eCd{HuX  
nEndPos = nStartPos[i+1]; ;mT}Q;F#  
} q/@+.q  
nEndPos[nEndPos.length-1] = nFileLength; 3UaW+@  
} ^ghYi|kQq  
} qxDMDMN  
"T{WOGU+  
Hy1$Kvub  
//启动子线程 }Nd1'BVf  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >}\s-/  
for(int i=0;i<nStartPos.length;i++) f;Oh"Yt  
{ "[!b5f3!I  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v/9DD%An  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !Ve0:$  
nStartPos,nEndPos,i); w7.,ch  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1Acs0` 3  
fileSplitterFetch.start(); ?'Hd0)yZ  
} l _%<U  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1O< 6=oH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g4b#U\D@)/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", IdN3Ea]  
nEndPos = " + nFileLength); |Y05 *!\P*  
// fileSplitterFetch[nPos.length-1].start(); mvK^')  
HE-5e): k  
Ak,JPz T  
//等待子线程结束 a#"orc j  
//int count = 0; -fk;Qq3O  
//是否结束while循环 rR :ZTfJs"  
boolean breakWhile = false; +Wg/ O -  
Jw8?o/1D@  
bXvO+I<  
while(!bStop) `-.2Z 0  
{ pB\:.?.pd  
write_nPos(); r dSL  
Utility.sleep(500); 8-NycG&)  
breakWhile = true; ~abyjM  
X!K>.r_Dg  
X=KW >  
for(int i=0;i<nStartPos.length;i++) ^)?Wm,{"w  
{ [#mk TY  
if(!fileSplitterFetch.bDownOver) N|$9v{ j_  
{ ~HhB@G!3  
breakWhile = false; #Zw:&' QB  
break; $BMXjXd}  
} :MY=Q]l  
} Y|Q(JX  
if(breakWhile) E`I(x&_  
break; 9D+k71"+  
$] "M`h  
zmGHI! tP  
//count++; n|)((W  
//if(count>4) Hp04apM:  
// siteStop(); lUB?eQuN_  
} <O 0Q]`i  
G(.G>8pf  
)f|`mM4DW!  
System.err.println("文件下载结束!"); +1YEOOfVY  
} OyVP_Yx,V  
catch(Exception e){e.printStackTrace ();} Lo1ySLo$G  
} ;W|NG3_y  
05R"/r*  
myR{ }G  
//获得文件长度 Lm~<BBp.  
public long getFileSize() ;7qIm83  
{ 38p"lT  
int nFileLength = -1; H^*AaA9-   
try{ A6]X aF  
URL url = new URL(siteInfoBean.getSSiteURL()); M,_ $s,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &{.IUg  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z8ea)_ {#  
\hgd&H0UU  
P0}{xq'k9v  
int responseCode=httpConnection.getResponseCode(); 9>w~B|/  
if(responseCode>=400) 3\@2!:>  
{ IZj`*M%3  
processErrorCode(responseCode); olv?$]  
return -2; //-2 represent access is error o& FOp'  
} rL1yq|]I  
HvG %##  
'~&W'='b;  
String sHeader; @6yc^DAA  
;6P>S4`w  
?iP7Ki  
for(int i=1;;i++) Pgr2 S I  
{ @d0f+9d  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7/IL" D  
//Utility.log(in.readLine()); aE5-b ub c  
sHeader=httpConnection.getHeaderFieldKey(i); kZz'&xdv'.  
if(sHeader!=null) "ktuq\a@  
{ I{cH$jt<  
if(sHeader.equals("Content-Length")) qx5`lm~L  
{ i`2SebDj'w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c%/b*nQ(=  
break; \L(cFjLIl  
} |qn 2b=  
}  C7ivA h  
else ]5"k%v|  
break; ?d-w#<AiV  
} BA: x*(%~  
} ESRj<p%W  
catch(IOException e){e.printStackTrace ();} &~P4yI;,  
catch(Exception e){e.printStackTrace ();} #j~FlY5  
}8x+F2i  
NS z }  
Utility.log(nFileLength); oL@-<;zKO  
T<pG$4_  
F)hj\aHm k  
return nFileLength; \t7yH]:>@  
} ][S q^5`  
6XWNJb  
%m |I=P  
//保存下载信息(文件指针位置) ZX:rqc  
private void write_nPos() }4YzP 4  
{ ad: qOm  
try{ .g*N +T6O  
output = new DataOutputStream(new FileOutputStream(tmpFile)); jXE:aWQht  
output.writeInt(nStartPos.length); B>L7UQ6_[  
for(int i=0;i<nStartPos.length;i++) gUru=p  
{ {1OxJn1hd  
// output.writeLong(nPos); $o?U=  
output.writeLong(fileSplitterFetch.nStartPos); Dm}eX:'{  
output.writeLong(fileSplitterFetch.nEndPos); ^<OYW|q?\r  
} \~hrS/$[$  
output.close(); rpR yB9  
} v;<gCzqQh  
catch(IOException e){e.printStackTrace ();} 5U~KYy^v  
catch(Exception e){e.printStackTrace ();} JPqd} :u3  
} %, psUOY  
Y.Zd_,qy  
|&=-Nm  
//读取保存的下载信息(文件指针位置) 2nkA%^tR  
private void read_nPos() =tP9n;D  
{ nv:Qd\UM  
try{ T%eBgseS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); JI-i7P  
int nCount = input.readInt(); fwz:k]vk  
nStartPos = new long[nCount]; G{} 2"/   
nEndPos = new long[nCount]; bXnUz?1!d  
for(int i=0;i<nStartPos.length;i++) Z&n[6aV'F  
{ (&e!u{I  
nStartPos = input.readLong(); D!o[Sm}JO[  
nEndPos = input.readLong(); fIoc)T  
} 4$KDf;m@  
input.close(); H]/ ~ #a  
} 031"D*W'i  
catch(IOException e){e.printStackTrace ();} M_ukG~/  
catch(Exception e){e.printStackTrace ();} q~R8<G%YK  
} V8M()7uJ  
Qfm$q~`D^W  
^Lgvey%  
private void processErrorCode(int nErrorCode) w{W+WJ  
{ P5<9;PPbZ  
System.err.println("Error Code : " + nErrorCode); A O:F*%Q u  
} L\2"1%8Wj  
H[~ D]RG}'  
"#O9ij  
//停止文件下载 @Ul3J )=m  
public void siteStop() MQ!4"E5"j  
{ epiviCYC  
bStop = true; 05LkLB  
for(int i=0;i<nStartPos.length;i++) n= <c_a)Nb  
fileSplitterFetch.splitterStop(); K<J,n!zc  
#BLHHK/[  
,j*9)  
} i=Qy?aU?  
} W Ej{2+  
//负责部分文件的抓取 J 4gtm"2)  
**FileSplitterFetch.java xQFY/Z  
*/ {^dq7!  
package NetFox; {1SsH ir>  
dS6 $  
jKml:)k  
import java.io.*; ?kO.>o  
import java.net.*; n|{K_! f  
 =1Sny7G  
E5^\]`9P  
public class FileSplitterFetch extends Thread { >N|?>M*  
;mU;+~YE  
MR1I"gqE}I  
String sURL; //File URL |E1U$,s~u  
long nStartPos; //File Snippet Start Position DJ"PP 5d  
long nEndPos; //File Snippet End Position QOXo(S  
int nThreadID; //Thread's ID 3lp'U&3`5  
boolean bDownOver = false; //Downing is over Lm4`O %  
boolean bStop = false; //Stop identical w.x&3aG  
FileAccessI fileAccessI = null; //File Access interface  +|LM"  
H4y9\ -  
^N/d`IAjv  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException r ]7: ?ir  
{ wo0j/4o  
this.sURL = sURL; O^MI073Q>t  
this.nStartPos = nStart; 6MVu"0#  
this.nEndPos = nEnd; vS8& ,wJ!  
nThreadID = id; 3xy2ZYw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 f5V-;  
} v])ew|  
i{6&/TBnr  
"UTW(~D'  
public void run() L/ 7AGR|;C  
{ @ual+=L  
while(nStartPos < nEndPos && !bStop) ,4Q4{Tx  
{ RzqgN*]lY  
-hXKCb4YU  
!.6n=r8 d  
try{ F{ %*(U  
URL url = new URL(sURL); v.(dOIrX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sE[`x^1'8  
httpConnection.setRequestProperty("User-Agent","NetFox"); a.V5fl0?I@  
String sProperty = "bytes="+nStartPos+"-"; CV @P +  
httpConnection.setRequestProperty("RANGE",sProperty); *tUOTA 3L  
Utility.log(sProperty); 3>h2 W  
^bv^&V&IB  
q-`&C  
InputStream input = httpConnection.getInputStream(); O t)}:oG  
//logResponseHead(httpConnection); &4:R(]|  
M(a%Qk?]/  
3mHzOs\jU  
byte[] b = new byte[1024]; lOt7 ij(,L  
int nRead; e-rlk5k%f  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) J%CCUl2  
{ g!XC5*}  
nStartPos += fileAccessI.write(b,0,nRead); INA3^p'w  
//if(nThreadID == 1) =@!t/LR7kg  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;stjqTd  
} hW#^H5?  
-P}A26qB  
t5+p]7  
Utility.log("Thread " + nThreadID + " is over!"); Y1h)aQ5{  
bDownOver = true; a?-&O$UHf\  
//nPos = fileAccessI.write (b,0,nRead); +*8su5:[&@  
} EX8+3>)  
catch(Exception e){e.printStackTrace ();} C 7C4 eW8  
} ooVs8T2  
} 9ngxkOGx  
yJI~{VmU7  
3=d%WPgQ  
//打印回应的头信息 +4:eb)e  
public void logResponseHead(HttpURLConnection con) bG]0|  
{ ?y? 9;;  
for(int i=1;;i++) I!L J&>  
{ ["D!IqI :  
String header=con.getHeaderFieldKey(i); D&):2F^9.  
if(header!=null) ?h[HC"V/2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {'M<dI$  
Utility.log(header+" : "+con.getHeaderField(header)); -Rpra0o. C  
else <[[yV  
break; yUnV%@.  
} UQu6JkbLL  
} :(A&8<}-6  
q}Q G<%VR  
G!Brt&_'  
public void splitterStop() 3Q$ 4`p;  
{ vclc%ws  
bStop = true; |*c1S -#  
} b&P)J|Fe  
 JQQ[jl;  
, '0#q  
}  v%:deaF  
E<jajYj  
Lng. X8D  
/* GNJ /|9  
**FileAccess.java ;}E}N:A  
*//文件访问(定位,写) NF&Sv  
package NetFox; ~LS</_N  
import java.io.*; iE''>Z  
RB %+|@c  
F%6wdM W  
public class FileAccessI implements Serializable{ o-@01_j  
F-s{#V1=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 y$%oR6 K7-  
RandomAccessFile oSavedFile; S($/Ov  
long nPos; %C/p+Tg  
#%[;v K  
Fl_}Auj{&(  
public FileAccessI() throws IOException v":q_w<k  
{ \x-2qlZ  
this("",0); 1%v6d !  
} |<u+Xi ~  
cANt7  
cTq@"v di  
public FileAccessI(String sName,long nPos) throws IOException 4G,FJjE`p  
{  2 q4p-  
oSavedFile = new RandomAccessFile(sName,"rw"); @mCe{r*`  
this.nPos = nPos; MSmr7%g3D  
oSavedFile.seek(nPos); .zgh,#=  
} Br!;Ac&N  
HS <Jp44  
)Jjp^U3Ub  
public synchronized int write(byte[] b,int nStart,int nLen) ?SNacN@r  
{ 8H4NNj Oy  
int n = -1; +ALrHFG  
try{ @/:4beh  
oSavedFile.write(b,nStart,nLen); 4NID:<  
n = nLen; %4nf(|8n  
} )9nW`d+  
catch(IOException e) I#2$CSJ  
{ qj;i03 +@  
e.printStackTrace (); =_`q;Tu=  
} X\m\yv}}  
/F;2wT;  
&ww-t..  
return n; xfeED^?  
} W\~ie}D{  
*F1TZ_GS  
\}Am]Y/ w  
} OWibmX  
ms0V1`  
}*(_JR4G  
/* tM]Gu?6  
**SiteInfoBean.java 0;l~B  
*/ h}a}HabA  
package NetFox; m FTuqujO  
iF+:j8 b  
?xqS#^Z  
public class SiteInfoBean { !+eU  
!K(  
Da 7(jA+  
private String sSiteURL; //Site's URL $Y7VA  
private String sFilePath; //Saved File's Path :%h1Q>F  
private String sFileName; //Saved File's Name 9jjeZc'  
private int nSplitter; //Count of Splited Downloading File w(V%EEk  
(B4)L%  
j;`pAN('  
public SiteInfoBean() rci,&>L"  
{//nSplitter的缺省值为5 av!;k2"  
//default value of nSplitter is 5 Ga 5s9wC  
this("","","",5); cjL)M=pIS  
} *F%1~  
<q=Zg7zB  
D;P=\i>9-  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |p/ *OFC6  
{ ]_(hUj._  
sSiteURL= sURL; inU5eronuj  
sFilePath = sPath; }W'j Dz7O  
sFileName = sName; )IcSdS0@M  
this.nSplitter = nSpiltter; sY!JB7!j  
=Smd/'`_  
J+t51B(a  
} ,^G+<T6  
^<!R%"o-  
&lLk[/b  
public String getSSiteURL() ?TpjU*Cxy  
{ JxinfWk  
return sSiteURL; gfK_g)'2U  
} ei4LE XQ16  
KfjWZ4{v  
T!]rdN!  
public void setSSiteURL(String value) Az@@+?,%Y  
{ iz=cjmV?  
sSiteURL = value; tn$TyCzckW  
} 4vbGXb}!  
<5G(Y#s/?  
HK :K~h  
public String getSFilePath() bIGcszWr  
{ *{VC<<`  
return sFilePath; ufk2zL8y  
} .hH_1Mo8  
!AXLoq$SY  
oIO@#   
public void setSFilePath(String value) :!s7B|_U  
{ .bY>++CAPA  
sFilePath = value; X`_tm3HC  
} u)Kiwa  
6MM\nIU)/  
9_wDh0b~p  
public String getSFileName() 5 <k)tF%  
{ Evj%$7H1L1  
return sFileName; *eHa4I  
} lt-3OcC  
>bWpj8Kv  
?jz\[0)s  
public void setSFileName(String value) |aenQA#  
{ '1DY5`i{  
sFileName = value; W#U|;@"  
} O\f`+Q`0  
4*Hzys[{  
E+i(p+=4  
public int getNSplitter() /TsXm-g#  
{ ,ASNa^7/>  
return nSplitter; $yi:0t8t  
} Ub f5 :  
!4Zy$69R  
*g*"bi*  
public void setNSplitter(int nCount) m19\H  
{ I )yaR+l  
nSplitter = nCount; e 1XKlgl  
} ~zfF*A  
} ASov/<D_q  
~x(|'`  
)SP"V~^Wn  
/* W*s=No3C  
**Utility.java 6p }a!  
*/ _O}U4aGMTC  
package NetFox; o]tfvGvU*  
pf'DbY!  
NV?x<LNWd  
public class Utility { s@$0!8sxm  
]8wm1_qV  
h8O\sKn  
public Utility() 9h+Hd&=  
{ !pU^?Hy=  
wz3X;1l`c  
!GvT{  
} 5\zR>Tg".  
Q?T+^J   
//线程睡眠 DqY"N ]  
public static void sleep(int nSecond) TU)Pi.Aa  
{ h-Y>>l>PW0  
try{ C3^3<  
Thread.sleep(nSecond); /"="y'Wx  
} SVwxK/Fci  
catch(Exception e) esZhX)dS  
{ !BW!!/U  
e.printStackTrace (); msCz\8Xd  
} z[ ;n2o|s  
} H0tu3Pqk  
hd9~Zw]V  
//日志 4 y}z+4  
public static void log(String sMsg) %JPr 7 }  
{ N/WtQSl  
System.err.println(sMsg); Zs}h>$E5_B  
} !nL94:8U  
:RIqA/  
>A]l|#Rz  
public static void log(int sMsg) #t1? *4.p  
{ jtfC3E,U  
System.err.println(sMsg); @I1*b>X~<  
} X&aQR[X  
} 4J`-&05O  
Ux?G:LLz  
q("l?'  
/* c8]%,26.  
**TestMethod.java g,*fpk  
*/ c)Ef]E\  
package NetFox; (&)uWjq `  
f#AuZ]h  
cahlYv'  
public class TestMethod {  w<!&%  
=; n>#<  
$l.8  
public TestMethod() S.iUiS"  
{ ///xx/weblogic60b2_win.exe %#4;'\'5  
try{ NR&a er  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0 )PZS>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); gjK: a@{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Bk.`G)t  
fileFetch.start(); bg9_$laDi  
} S]T71W<i  
catch(Exception e){e.printStackTrace ();} 2>x[_  
4E!Pxjl3a  
=$~x]  
} +NB5Fd4  
;CL^2{  
*WzPxQ_  
public static void main(String[] args) LM"b%  
{ GQ.akA_(  
new TestMethod(); Z^mIGy}  
} `ALQSo~l  
} 23;\l   
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