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http断点续传简单实现(java)

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/* 1$rrfg  
**SiteFileFetch.java HXRK<6k$  
*/ H%`|yUE(  
package NetFox; /mFa*~dj2  
import java.io.*; g+92}$_  
import java.net.*; vhu5w#]u*  
:X ~{,J  
)x&OdFX  
public class SiteFileFetch extends Thread { &oqzQ+H  
UNd+MHE74I  
&io*pmUm6  
SiteInfoBean siteInfoBean = null; //文件信息Bean -S *MQA4  
long[] nStartPos; //开始位置 @1G`d53N  
long[] nEndPos; //结束位置  Q~AK0W  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 73'.TReK  
long nFileLength; //文件长度 99..]  
boolean bFirst = true; //是否第一次取文件 'P<T,:z?  
boolean bStop = false; //停止标志 =;@?bTmqD  
File tmpFile; //文件下载的临时信息 dnUiNs8  
DataOutputStream output; //输出到文件的输出流 A+1>n^^_<  
9mfP9  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ixIfJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException Xu#K<#V  
{ tD !$!\`O  
siteInfoBean = bean; ]h0K*{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jCv%[H7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %y}l^P5z  
if(tmpFile.exists ()) >6zXr.  
{ a76`"(W  
bFirst = false; V61.UEN  
read_nPos(); zWEt< `1M  
} 4GTB82V$  
else f8?c[%br  
{ \3v}:E+3  
nStartPos = new long[bean.getNSplitter()]; 2zN%Z!a#J  
nEndPos = new long[bean.getNSplitter()]; qT+:oMrTSm  
} 7BDoF!kCx  
S`?cs^?  
gw);b)&mx  
8st~ O  
} u4p){|x7s  
V;-YM W  
$S _VR  
public void run() pJ 7="n  
{ >rb8A6  
//获得文件长度 2pQdDbm  
//分割文件 C [h^bBq  
//实例FileSplitterFetch +HOHu*D  
//启动FileSplitterFetch线程 -%#F5br%  
//等待子线程返回 "G3zl{?GP  
try{ B '"RKs]  
if(bFirst) 5Myp#!|x:  
{ H]/!J]  
nFileLength = getFileSize(); zV8^Hxl  
if(nFileLength == -1) ?h4Rh0rkX  
{ 49m}~J=*  
System.err.println("File Length is not known!"); C0@[4a$8f  
} B&oP0 jS  
else if(nFileLength == -2) d;9F2,k$w  
{  E\! <=  
System.err.println("File is not access!"); T=n)ea A  
} nd/.]"  
else dNMz(~A[Y  
{ Y"&1jud4xl  
for(int i=0;i<nStartPos.length;i++) t*'U|K4L/  
{ Ei[>%Ah  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8bIwRVA2\  
} b4HUgW3Ac  
for(int i=0;i<nEndPos.length-1;i++) $-:j'e:j  
{ 6$|!_94>*)  
nEndPos = nStartPos[i+1]; %+,7=Wt-  
} &=d0'3k>  
nEndPos[nEndPos.length-1] = nFileLength; 1SYBq,[])  
} 9 L^:N)-  
}  + Y  
U F ]g6u  
XV> )[Nd\H  
//启动子线程 P,@ :?6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $rG~0  
for(int i=0;i<nStartPos.length;i++) GE{u2<%@  
{ 56 raZC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TQ\\/e:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <CnTiS#  
nStartPos,nEndPos,i); lZa L=HS#L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c/q -WEKL  
fileSplitterFetch.start(); m|5yET  
} bez_|fY{T  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $WV N4fg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]7ZY|fP2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", c<gvUVHIxR  
nEndPos = " + nFileLength); _PR> <L_  
// fileSplitterFetch[nPos.length-1].start(); OAhCW*B  
bq<DW/  
sC=fXCGW\p  
//等待子线程结束  #nS  
//int count = 0; j>70AE3[8  
//是否结束while循环 ~20O&2  
boolean breakWhile = false; 3LaqEj  
.;&1"b8G  
psHW(Z8G  
while(!bStop) oMj;9,WK'  
{ JNYFu0  
write_nPos(); 5#SD$^  
Utility.sleep(500); I2$.o0=3Y  
breakWhile = true; e+t2F |xDh  
gVs8W3GW  
g}\Yl.  
for(int i=0;i<nStartPos.length;i++) oL2 a:\7  
{ ATb[/=hP<R  
if(!fileSplitterFetch.bDownOver) xxN=,p  
{ wwtk6;8@  
breakWhile = false; mz~aSbb|  
break; i9FHEu_  
} 0WjPo  
} m:1f7Z>  
if(breakWhile) ??!+2G#%!  
break; ' N@1+v=  
]hxE^/87  
(KF=v31_m  
//count++; ?u`TX_OsB  
//if(count>4) IC6}s  
// siteStop(); ; iK9'u  
} &!lGx7zf  
D6KYkN(,v  
Gg3cY{7  
System.err.println("文件下载结束!"); *0 0K3  
} ?1z." &  
catch(Exception e){e.printStackTrace ();} Y0||>LX  
} n' \poB?  
DhL]\ 4  
'01ifA^  
//获得文件长度 ,KMt9 <  
public long getFileSize() %S<0l@=5`l  
{ cG"+n@ \  
int nFileLength = -1; +s}"&IV%  
try{ Q599@5aS  
URL url = new URL(siteInfoBean.getSSiteURL()); u5, \Kz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w1je|Oil  
httpConnection.setRequestProperty("User-Agent","NetFox"); Zljj  
`nxm<~-\  
kAEm#oz=g  
int responseCode=httpConnection.getResponseCode(); xt%-<%s%f  
if(responseCode>=400) 39w|2%(O.  
{ ]0VjVU-  
processErrorCode(responseCode); ?~;8Y=O  
return -2; //-2 represent access is error 8}& O7zO?  
} )PRyDC-  
c teUKK.|)  
uHv9D%R  
String sHeader; d{UyiZm\  
nH#|]gVI  
K&t+3O  
for(int i=1;;i++) 4&Q.6HkL  
{ O;u&>BMk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~"E@do("  
//Utility.log(in.readLine()); yX}riXe  
sHeader=httpConnection.getHeaderFieldKey(i); }4!R2c  
if(sHeader!=null) 8u,f<XHi"a  
{ E6{|zF/3'  
if(sHeader.equals("Content-Length")) 5AWIk,[  
{ 0$-N  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); cMCGaaLU  
break; poqcoSL"}  
} r.5}Q?  
} _`/: gkZS  
else 'nOc_b0  
break; ltKUpRE\?  
} gg>O:np8  
} DA5kox&cU  
catch(IOException e){e.printStackTrace ();} Z\{"/( Hi  
catch(Exception e){e.printStackTrace ();} Ut;, Z  
".9 b}}  
6]=R#d 7U  
Utility.log(nFileLength); ,qS-T'[v,(  
Hoaf3 `n  
):@XMECa  
return nFileLength; o<*H!oyP\  
} m"{D}(TA  
CH6^;.  
fa7I6 i  
//保存下载信息(文件指针位置) Pd99vq/  
private void write_nPos() w&eX)!  
{ vjy59m  
try{ kxJ! #%w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); d]JiJgfa%  
output.writeInt(nStartPos.length); %1uY  
for(int i=0;i<nStartPos.length;i++) hrpql_9.  
{ #S57SD  
// output.writeLong(nPos); n M +(  
output.writeLong(fileSplitterFetch.nStartPos); "t4$%7L]  
output.writeLong(fileSplitterFetch.nEndPos); k^ CFu  
} eIz T(3(  
output.close(); vZHm'  
} 35dbDgVz$  
catch(IOException e){e.printStackTrace ();} jl;%?bx  
catch(Exception e){e.printStackTrace ();} j4v.8;  
} *C~O[:6D  
R^`#xQ  
S\"/=|\  
//读取保存的下载信息(文件指针位置) kKU,|> 3h  
private void read_nPos() \ /3Xb  
{ VP|ga }(  
try{ EkV LSur  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  #K8kz  
int nCount = input.readInt(); g1JBssw&m  
nStartPos = new long[nCount]; }B=`nbgIG7  
nEndPos = new long[nCount]; orB8q((  
for(int i=0;i<nStartPos.length;i++) ;(cq aB  
{ #$&!)13  
nStartPos = input.readLong(); /8\gT(@  
nEndPos = input.readLong(); 1epj/bB&  
} 9?xMsu-H  
input.close(); DYJ F6O  
} -r%3"C=m  
catch(IOException e){e.printStackTrace ();} +I$ k_  
catch(Exception e){e.printStackTrace ();} xFU*,Y  
} 'lPt.*Y<u  
4ZY0!'be-R  
n\f8%z  
private void processErrorCode(int nErrorCode) s2-`}LL  
{ VKW9Rn9Qg  
System.err.println("Error Code : " + nErrorCode); wb@TYvDt  
} d4Y8q1  
|!VSed#FSn  
`GsFvxz  
//停止文件下载 Sm6hyZFy  
public void siteStop() 1wX0x.4d  
{ R;2tb7o  
bStop = true; }%K)R 5C  
for(int i=0;i<nStartPos.length;i++) =-XI)JV#  
fileSplitterFetch.splitterStop(); 0{0|M8  
 jpc bW  
qJ).;S{AAt  
} |{ E\ 2U  
} T %   
//负责部分文件的抓取 -e6~0%X  
**FileSplitterFetch.java K:PPZ|  
*/ ]?n)!u  
package NetFox; !"w1Pv,  
?!R Z~~d  
C5Fk>[fS  
import java.io.*; >k gL N  
import java.net.*; |D `r o  
J7FCW^-`3  
~)';[Ha  
public class FileSplitterFetch extends Thread { 5l"/lGw  
W`}C0[%VW  
@D<q=:k  
String sURL; //File URL mJBvhK9%  
long nStartPos; //File Snippet Start Position s68&AB   
long nEndPos; //File Snippet End Position %E\&9,  
int nThreadID; //Thread's ID L0\97AF  
boolean bDownOver = false; //Downing is over a1lF8;[  
boolean bStop = false; //Stop identical N*~G ]  
FileAccessI fileAccessI = null; //File Access interface {U:c95#.!S  
qDR`)hle  
*>x~`  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q8U*  
{ RP}.Ei  
this.sURL = sURL; ?]i.Zi\[f  
this.nStartPos = nStart; so~vnSQ!x  
this.nEndPos = nEnd; 4CR.=  
nThreadID = id; {0J TN%e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9,h'cf`F  
} ?T+Uu  
fv1pA+zN[  
6$"gm$3O]  
public void run() o)_;cCr)q  
{ ?LP&VU1  
while(nStartPos < nEndPos && !bStop) 7_,)"J2^  
{ wB(A['k  
uWs5 +  
>EQd;Af  
try{ @ lo6?9oNo  
URL url = new URL(sURL); 4a'GWzUtS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3B }Oy$p  
httpConnection.setRequestProperty("User-Agent","NetFox"); $ b Q4[  
String sProperty = "bytes="+nStartPos+"-"; !}u'%  
httpConnection.setRequestProperty("RANGE",sProperty);  yQkj4v{  
Utility.log(sProperty); y#[PQ T  
obUX7N  
i3T]<&+j5  
InputStream input = httpConnection.getInputStream(); jOuz-1x,&  
//logResponseHead(httpConnection); }R.<\  
_1D'9!+   
p=T,JAIt  
byte[] b = new byte[1024]; sq6|J])GgU  
int nRead; "xS?#^a  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) m791w8Vr  
{ 9UD~$_<\  
nStartPos += fileAccessI.write(b,0,nRead); SKx&t-  
//if(nThreadID == 1) =d#3& R]p  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %xE9vN;  
} P{ AJH1  
2jQ|4$9j  
h=uv4&  
Utility.log("Thread " + nThreadID + " is over!"); OidF{I*O  
bDownOver = true; wyqXD.o f  
//nPos = fileAccessI.write (b,0,nRead); 3Lx]-0h  
} S|U/m m  
catch(Exception e){e.printStackTrace ();} ^rd]qii"  
} &%QtUPvr9  
} BdHLow  
'%&i#Eb  
q4)8]Y2  
//打印回应的头信息 V#!ftu#c?  
public void logResponseHead(HttpURLConnection con) \ "193CW!  
{ Vj^<V|=  
for(int i=1;;i++) e<_p\LiOS  
{ ocwh*t)<k  
String header=con.getHeaderFieldKey(i); wIi_d6?  
if(header!=null) 2=pVX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :-x F=Y(;  
Utility.log(header+" : "+con.getHeaderField(header)); S<Zb>9pl  
else w!{g^*R+!  
break; !(=bH"P  
} b[<Q_7~2  
} v#EXlpS  
=i jGB~  
r"s <;  
public void splitterStop() P$MAURFm  
{ Yrb[:;Y  
bStop = true; a =LjFpv/]  
} rYI9?q  
^:Vwblv(  
tWkD@w`Lnn  
} [ F id  
+R}(t{b#  
>mzK96  
/* a%2r]:?^?  
**FileAccess.java K-V NU  
*//文件访问(定位,写) SooSOOAx[  
package NetFox; Z/=x(I0  
import java.io.*; Pyc/6~ ?  
I~lX53D  
ndRy&[f7  
public class FileAccessI implements Serializable{ ]<D9Q>  
RFyeA. N  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *Q bPz4,"  
RandomAccessFile oSavedFile; ^J0*]k%   
long nPos; PfTjC"`,  
D0(QZrVa  
Y$8 >fv  
public FileAccessI() throws IOException 3RpDIl`0  
{ ~Ein)5  
this("",0); U[5  
} (r_xs  
,]e!OZ[$m  
/M>8ad  
public FileAccessI(String sName,long nPos) throws IOException M~Tq'>Fn  
{ <'H^}gQow  
oSavedFile = new RandomAccessFile(sName,"rw"); #&vP(4p  
this.nPos = nPos; Yrp WGK520  
oSavedFile.seek(nPos); qv<[f=X9|  
} oy90|.]G  
3{o5AsVv  
h amn9  
public synchronized int write(byte[] b,int nStart,int nLen) vluA46c  
{ BR5r K  
int n = -1; )cc:Z7p  
try{ eaQ)r?M  
oSavedFile.write(b,nStart,nLen); Ct[{>asun  
n = nLen; ^S*~<0NQ'  
} > t *+FcD  
catch(IOException e) kDuN3  
{ il=y m  
e.printStackTrace (); F0 WM&{v  
} |]`\ak  
oGpyuB@A/  
wJA`e)>  
return n; qYj EQz  
} X-Y:)UT  
0sW=;R2  
OgjSyzc  
} /5:C$ik  
Sw~jyUEr  
|<&9_Aq_  
/* [>xwwm  
**SiteInfoBean.java 2<Lnfc<^k  
*/ 3A2X1V"  
package NetFox; G" &9u2k  
X $LX;Lv  
Y85M$]e,  
public class SiteInfoBean { -7)%J+5  
'r6s5 WC  
MKSiOM  
private String sSiteURL; //Site's URL fvKb0cIx]  
private String sFilePath; //Saved File's Path nff&~lwhZ  
private String sFileName; //Saved File's Name F)KUup)gc  
private int nSplitter; //Count of Splited Downloading File 9u";%5 4  
dM"Suw  
g+h)s!$sB  
public SiteInfoBean() #|76dU  
{//nSplitter的缺省值为5 xwG=&+66  
//default value of nSplitter is 5 uxF88$=!t  
this("","","",5); Ht,_<zP;  
} q h;ahX~  
4PUSFZK?  
v5U\E`)s  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5tI4m#y2  
{ B:dk>$>uQ  
sSiteURL= sURL; ! 9B| `  
sFilePath = sPath; D. !m*oq  
sFileName = sName; 4;@|tC|u  
this.nSplitter = nSpiltter; i_?";5B"  
y\&GPr  
C=L_@{^Rgb  
} =E@wi?  
lquY_lrri  
i{zg{$U  
public String getSSiteURL() BG!;9Z{u  
{ w7NJ~iy  
return sSiteURL; ed$g=qs>  
} kylR)  
7:x%^J+  
B,?Fjot#m  
public void setSSiteURL(String value) uKF?UXc  
{ HlEp Dph%  
sSiteURL = value; e<s56<3j  
} 1'tagv?  
'3S S%W  
u*u>F@C8  
public String getSFilePath() 8%OS ,Z  
{ p@`rBzGp  
return sFilePath; w8E6)wF=7  
} e _\]Q-  
&U\Xy+  
!l!^`c  
public void setSFilePath(String value) (.Tkv Uj`  
{ -#srn1A>  
sFilePath = value; [V'3/#Z  
} tpw0j CVu  
&>kklP  
~7aBli=  
public String getSFileName() ~#3h-|]*  
{ UO(B>Abp  
return sFileName; MJ^NRT0?b  
}  5|2v6W!e  
[9S\3&yoh  
No8~~  
public void setSFileName(String value) PGZ.\i  
{ kb<Nuw  
sFileName = value; u=B_cA}:  
} x9}D2Ui  
:<Z*WoEmt  
n|`L>@aw,  
public int getNSplitter() ;n?72&h  
{ jR<yV  
return nSplitter; lN94 b3_W  
} - Z?rx5V;t  
ldcYw@KQ  
}}Ah-QU  
public void setNSplitter(int nCount) DueQ1+ P  
{ 2Wz/s 0`  
nSplitter = nCount; Hm2}xnY  
} 41 sClC"  
} ~J1;Z0}#  
|0:&d w?*!  
Ep-{Ew{T_=  
/* v w$VR PW  
**Utility.java A[L+w9  
*/ pC,MiV$c"  
package NetFox; "-JJ6Bk  
pnin;;D*  
\zA$|) x  
public class Utility { O[[:3!6q  
h _6QVab@  
#iD5& klo\  
public Utility() UKyOkuY:w  
{ rQT@:$ )  
Hb5^+.xur  
V#jFjObTN  
} 9u<4Q_I`  
=)5eui>{  
//线程睡眠 Ro :/J  
public static void sleep(int nSecond) CpHF3o`Z6  
{ H?tonG.^(  
try{ Kd}cf0  
Thread.sleep(nSecond); R?3^Kx  
} S N_!o2F2  
catch(Exception e) ^S!^$d*  
{ sl^i%xJ|l'  
e.printStackTrace (); ~5$V8yfx h  
} g2%&/zq/  
} X~XpX7d!  
5`,qKJ  
//日志 + 5E6|  
public static void log(String sMsg) %.,-dV'  
{ J^[>F{8!n  
System.err.println(sMsg); QUd`({/@:  
} ]5IG00`  
tU7,nE>p  
A2 r1%}{  
public static void log(int sMsg) )@)wcf!b  
{ FNlzpCT~L  
System.err.println(sMsg); ?_36uJo}  
} "e62g  
} SPKGbp&  
$ hwJjSZ0  
"l~wzPY)  
/* nokk! v/  
**TestMethod.java v>zeK  
*/ I$sJ8\|gw'  
package NetFox; !7ct=L  
+r[u4?  
bTB/M=M  
public class TestMethod { 0-#SvTf>;:  
@? 4-  
K~"uZa^s  
public TestMethod() Q#NXJvI  
{ ///xx/weblogic60b2_win.exe B0I(/ 7  
try{ 6wH]W+A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); O o9 ePw7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A-<\?13uW  
SiteFileFetch fileFetch = new SiteFileFetch(bean); CuRYtY@9  
fileFetch.start(); r@L19d)J  
} Q?Vq/3K;  
catch(Exception e){e.printStackTrace ();} +')\,m "z  
Sz4YP l  
)70-q yA  
} `*nVLtT Y  
WP-?C<Iw  
N{v <z 6  
public static void main(String[] args) 6jjmrc[#}X  
{ >#).3  
new TestMethod(); (Qmpz  
} ju#/ {V;D  
} GkqKIs  
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