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http断点续传简单实现(java)

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/* (`}O!;/E}  
**SiteFileFetch.java 7<V(lX.{  
*/ lc/q0  
package NetFox; {s}@$rW  
import java.io.*; Y|FJ1x$r  
import java.net.*; OHeVm-VC  
S_cba(0-|\  
cDMA#gp  
public class SiteFileFetch extends Thread { EB'(%dH  
mjbr}9  
W/U&w.$  
SiteInfoBean siteInfoBean = null; //文件信息Bean V.Pb AN  
long[] nStartPos; //开始位置 o0Qy?14T-  
long[] nEndPos; //结束位置 B@Zed Xi  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *9}2Bmojv  
long nFileLength; //文件长度 o.DT`L8  
boolean bFirst = true; //是否第一次取文件 JFVal#  
boolean bStop = false; //停止标志 T69'ta32V  
File tmpFile; //文件下载的临时信息 HVzG }r(J  
DataOutputStream output; //输出到文件的输出流 :&Xy#.un  
CK1Xdyf_S  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 4CO:*qG)o  
public SiteFileFetch(SiteInfoBean bean) throws IOException (9x8,f0z  
{ CW>f;  
siteInfoBean = bean; {.2A+JT,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]Lq9Ompf(t  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); cCN[c)[c|  
if(tmpFile.exists ()) L_uliBn  
{ O#Ab1FQn  
bFirst = false; 1,fjdd8OM;  
read_nPos(); afRUBjs  
} .3k"1I '\  
else _@0>y MZ^  
{ e"^* ~'mJ  
nStartPos = new long[bean.getNSplitter()]; VJ P]Jy_  
nEndPos = new long[bean.getNSplitter()]; jJ-j   
} b@@`2O3"  
6R% I)  
(NUwkAO M}  
'M2Jw8i  
} u= ( kii=/  
RWf4Wh?d  
('!90  
public void run() &G?b|Tb2  
{ ?1 $.^  
//获得文件长度 zRsG$)B  
//分割文件 A<.`HCv2  
//实例FileSplitterFetch . Rxz;-VA  
//启动FileSplitterFetch线程 SLRQ3<0W_  
//等待子线程返回 }./__gJ  
try{ iF2/:iP  
if(bFirst) :WejY`}H%  
{ |) QE+|?P  
nFileLength = getFileSize(); #kT3Sx  
if(nFileLength == -1) rz0~W6 U  
{ +9>t; Ty  
System.err.println("File Length is not known!"); 2w93 ~j  
} 'Uqz,  
else if(nFileLength == -2) :N5R.@9  
{ gTZ1LJ  
System.err.println("File is not access!"); '~A~gK0  
} n?vrsqmZ  
else h_L-M}{OG  
{ bY7d  
for(int i=0;i<nStartPos.length;i++) K:/%7A_{  
{ xS]=WO*  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^yiRrcOo  
} [_ESR/&N  
for(int i=0;i<nEndPos.length-1;i++) c*ac9Y'o  
{ mjG-A8y  
nEndPos = nStartPos[i+1]; * 3mF.^  
} ) 2C`;\/:  
nEndPos[nEndPos.length-1] = nFileLength; " cx\P,<  
} %gDMz7$~  
} ^.y}2  
<hgt{b4  
iqURlI);P  
//启动子线程 ?)k;.<6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0m_c43+^  
for(int i=0;i<nStartPos.length;i++) I:[^><?E  
{ )xIk#>)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2ku\R7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), + |MHiC  
nStartPos,nEndPos,i); ]cLO-A  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hrPm$`  
fileSplitterFetch.start(); Lh0Pvq0C  
} vFXih'=_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @D&VOJV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9/TF #  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;muxIr`?  
nEndPos = " + nFileLength); m[,! orq  
// fileSplitterFetch[nPos.length-1].start(); xpt*S~  
8W Mhe=[  
V~` ?J6  
//等待子线程结束 XfmPq'#Z  
//int count = 0; 57^ X@ra$  
//是否结束while循环 LC)-aw>-  
boolean breakWhile = false; q-O=Em<*  
.4pWyqU)!  
|T0jq  
while(!bStop) ZAVjq;bq  
{ Nw'i;}0v7r  
write_nPos(); e*.l6H/B  
Utility.sleep(500); 6VpT*,2d~  
breakWhile = true; ^6`"f  
<eK F  
F Cg{!h  
for(int i=0;i<nStartPos.length;i++) 9mfqr$3  
{ E'zLgU)r`  
if(!fileSplitterFetch.bDownOver) {(#Dou  
{ H'Q4IRT  
breakWhile = false; >QV=q`I  
break; LO0<=4iN(  
} h-<2N)>!  
} :786Z,')  
if(breakWhile) { [ QCuR  
break; zts%oIgV  
HM ;9%rtO  
 Svj%O(  
//count++; 1>bG]l1//  
//if(count>4) F1%-IBe  
// siteStop(); \zCT""'i  
} =n|n%N4Y  
vfPL;__{Y]  
.XQ_,  
System.err.println("文件下载结束!"); ;:NW  
} `b 6j7  
catch(Exception e){e.printStackTrace ();} ,,vl+Z <&  
} YNV4w{>FD  
qV2aa9p+  
#]pFE.o  
//获得文件长度 T7_i: HU%  
public long getFileSize()  oZTKG'  
{ 45fk+#  
int nFileLength = -1; zX{K\yp  
try{ Y8YNRyc=  
URL url = new URL(siteInfoBean.getSSiteURL()); [A99e`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ib8@U}Vn1  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7xidBVx  
q_K8vGm4e  
%7WGodlXW  
int responseCode=httpConnection.getResponseCode(); *^+8_%;1  
if(responseCode>=400) qELy'\  
{ k_$:?$  
processErrorCode(responseCode); ^F/gJ3_;  
return -2; //-2 represent access is error `) s]T.-  
} fH[Yc>(oj  
^y"5pf SR  
@%mJw u  
String sHeader; Oo<L~7B  
7kJ =C  
luAmq+  
for(int i=1;;i++) V*HkF T  
{ x`/"1]Nf  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :s|" ZR  
//Utility.log(in.readLine()); t_cNH@^3<3  
sHeader=httpConnection.getHeaderFieldKey(i); 5lehASBz  
if(sHeader!=null) _s{on/u  
{ vqDd][n  
if(sHeader.equals("Content-Length")) ";\na!MT  
{ 5{ ?J5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); z.EpRJn  
break; ZdQt!  
} .=rS,Tpo  
} n@IpO i$Q  
else ^)|8N44O  
break; rbfP6t:c3  
} "i3wc&9!?W  
} ^5n"L2 9V  
catch(IOException e){e.printStackTrace ();} Te&F2`vo  
catch(Exception e){e.printStackTrace ();} fHK`u'  
t;g= @o9YA  
<49Gsm&0  
Utility.log(nFileLength); M}Sn$h_  
{uVvo=3  
hfzmv~*  
return nFileLength; |Et8FR3[m  
} \/E+nn\)  
M'gw-^(  
Xtv^q> !  
//保存下载信息(文件指针位置) M:&g5y&  
private void write_nPos() RlJt+lnV  
{ A|3'9iL{9  
try{ !>gi9z,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )nncCU W  
output.writeInt(nStartPos.length); Rs*]I\  
for(int i=0;i<nStartPos.length;i++) 4#jW}4C{  
{ aPD4S&"Q  
// output.writeLong(nPos); O2z{>\  
output.writeLong(fileSplitterFetch.nStartPos); z^;0{q,  
output.writeLong(fileSplitterFetch.nEndPos); IpX.ube  
} y>4r<Y ZQ  
output.close(); S3Q^K.e?  
} `1;m:,9  
catch(IOException e){e.printStackTrace ();} @APv?>$)  
catch(Exception e){e.printStackTrace ();} Ll 4/P[7:?  
} =QG@{?JTl  
QnHb*4<  
4KH8dau.fF  
//读取保存的下载信息(文件指针位置) Vqr#%. N  
private void read_nPos() xw[KP [(  
{ 4}C^s\?z  
try{ 1< 22,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); IY$v%%2WZ  
int nCount = input.readInt(); C%#%_ "N  
nStartPos = new long[nCount]; :x85:pa  
nEndPos = new long[nCount]; `[.b>ztqgJ  
for(int i=0;i<nStartPos.length;i++) |%p;4b  
{ S}QvG&c  
nStartPos = input.readLong(); \53(D7+  
nEndPos = input.readLong(); njhDrwN  
} O}$@|w(8;  
input.close(); +hoZW R  
} 6} b1*xQ  
catch(IOException e){e.printStackTrace ();} e+`LtEve0  
catch(Exception e){e.printStackTrace ();} {w/{)B nPG  
} #J4{W84B  
W|C>X=zTi  
v2Lx4:dzi  
private void processErrorCode(int nErrorCode) l~_] k  
{ e+'PRVc  
System.err.println("Error Code : " + nErrorCode); gXrXVv<)yw  
} =t@8Y`9w  
)Q:.1Hgl  
e u{  
//停止文件下载 L$T23*9XY  
public void siteStop() BC*)@=7fx  
{ 4gyC?#Ede  
bStop = true; c:[z({`  
for(int i=0;i<nStartPos.length;i++) I[P43>F3  
fileSplitterFetch.splitterStop(); Ii*tux!S  
hh%f mc  
pK_n}QW  
} Q:nBx[%  
} 0j@nOj(3  
//负责部分文件的抓取 #ZzFAt  
**FileSplitterFetch.java aHhr_.>X  
*/ | DB7o+4  
package NetFox; ">-J+ST%  
*/8b)I}yY  
OD;-0Bj  
import java.io.*; PIo8mf/  
import java.net.*; p= fj1*  
.k_> BD];  
S5%I+G3  
public class FileSplitterFetch extends Thread { |"gg2p  
)R~l@QBN  
7IEG%FY T  
String sURL; //File URL A(j9T,!  
long nStartPos; //File Snippet Start Position oR``Jiob|  
long nEndPos; //File Snippet End Position _lK+/"-l  
int nThreadID; //Thread's ID aRt`IcZYz  
boolean bDownOver = false; //Downing is over !Eqp,"ts7  
boolean bStop = false; //Stop identical VXfp=JE  
FileAccessI fileAccessI = null; //File Access interface F'NX  
uD'GI  
u*W6fg/"  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /Soc,PjZ  
{ Bz7rf^H`Z  
this.sURL = sURL; G@.TE7a2Z  
this.nStartPos = nStart; bi:TX<K+  
this.nEndPos = nEnd; Ne!0`^`~  
nThreadID = id; 6}q8%[l|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6ct'O**k*&  
} +mgm39  
Es7+bFvsE8  
f!H~BMA+a  
public void run() w!GPPW(  
{ )qbjX{GZ7  
while(nStartPos < nEndPos && !bStop) zw2qv'  
{ L lNd97Z  
Tgf\f%,h  
AlVB hR`  
try{ @N(*1,s2  
URL url = new URL(sURL); NQ9/,M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cN?}s0  
httpConnection.setRequestProperty("User-Agent","NetFox"); T_=IH~"  
String sProperty = "bytes="+nStartPos+"-"; 3RbPc8($Y  
httpConnection.setRequestProperty("RANGE",sProperty); neLQ>WT L  
Utility.log(sProperty); ^KlW"2:  
yJ0q)x sS  
J*%XtRio  
InputStream input = httpConnection.getInputStream(); 8.Z9 i  
//logResponseHead(httpConnection); WP}NHz4H  
$2><4~T;|A  
j0X Jf<  
byte[] b = new byte[1024]; >>>&{>}!  
int nRead; bF"1M#u:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &"R`:`XF  
{ 3D2\#6yo  
nStartPos += fileAccessI.write(b,0,nRead); aN^x]0P!0  
//if(nThreadID == 1) ]YF_c,Q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y\C_HCU H  
} #a$k3C  
lx)Bj6  
Q 1:7 9  
Utility.log("Thread " + nThreadID + " is over!"); $~h\`vF&  
bDownOver = true; Vw@?t(l>  
//nPos = fileAccessI.write (b,0,nRead); gfPR3%EXs  
} 'xG:v)(  
catch(Exception e){e.printStackTrace ();} %fF0<c^-U  
} eX 0due  
} A,u}p rwH  
H,Y+n)5  
G+S MH`h  
//打印回应的头信息 xG7/[ jG  
public void logResponseHead(HttpURLConnection con) 5Z<y||=  
{ 0W6j F5T  
for(int i=1;;i++) 5ltrr(MeD  
{ 8TE2q Pm  
String header=con.getHeaderFieldKey(i); ?TLzOYJp  
if(header!=null) Y9w^F_relL  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |ctcY*+  
Utility.log(header+" : "+con.getHeaderField(header)); zF7*T?3b"  
else  yh'uH  
break; N!Cy)HnS\w  
} YD@n8?~$$  
} LJ{P93aq`^  
X$0&tmum  
[AA*B  
public void splitterStop() cvk$ I"q+  
{ TGSkJ 1Lx  
bStop = true; VJoobu1h  
} p* Q *}V  
XD8Q2un  
sWGc1jC?.F  
} GU,ztO.w3  
?E6 C|A$I  
cq0#~20  
/* ] v8.ym  
**FileAccess.java Q|] 9  
*//文件访问(定位,写) 1(`UzC=R|  
package NetFox; Pe`eF(J  
import java.io.*; M\!z='Fi  
_9 B ^@~  
5f- eWW]!  
public class FileAccessI implements Serializable{ tXg>R _\C  
L Rn)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z<jH{AU  
RandomAccessFile oSavedFile; iAn]hVW  
long nPos; %h^ f?.(:  
NN"!kuM  
\ 0J &^C  
public FileAccessI() throws IOException 8Rric[v  
{ ?Mj@;O9>'  
this("",0); 9J(jbJ7p  
} Pq<]`9/w^w  
)ePQN~#K}  
lG/h[  
public FileAccessI(String sName,long nPos) throws IOException 6b7SA ,  
{ KwxO%/-}S  
oSavedFile = new RandomAccessFile(sName,"rw"); AD0pmD  
this.nPos = nPos; cd3;uB4\,  
oSavedFile.seek(nPos); |<Rf^"T  
} zv>7;En3  
_I<LB0kgf.  
Ef"M e(  
public synchronized int write(byte[] b,int nStart,int nLen) /s|4aro  
{ +)U>mm,  
int n = -1; --BS/L-  
try{ C/{%f,rU  
oSavedFile.write(b,nStart,nLen); %]\IC(q  
n = nLen; +/|t8zFWs  
} V'm4DR#M  
catch(IOException e)  }0f"SWO>  
{ s+7#TdhA  
e.printStackTrace (); UR' P,  
} rL3 f%L  
G\ m`{jv  
i8+[-mh  
return n; tO8<N'TD  
} /5&' U!:+  
SMIr@*R  
u0?,CQPL  
} t(Sjo8, b  
=1e>$E#  
Y-y<gW  
/* 9yWQ}h  
**SiteInfoBean.java >j}.~$6dj_  
*/ m6iQB\ \  
package NetFox; =ec"G2$?"  
|x/00XhS  
uh 3yiDj@a  
public class SiteInfoBean { |4?O4QN  
M.h8Kr!.  
w^N3Ma  
private String sSiteURL; //Site's URL s;!Tz)  
private String sFilePath; //Saved File's Path T$vDw|KSVP  
private String sFileName; //Saved File's Name M_Z(+k{Gy  
private int nSplitter; //Count of Splited Downloading File :}{,u6\  
@q<F_'7is  
m |%ly  
public SiteInfoBean() l/:23\  
{//nSplitter的缺省值为5 Ow f:Kife  
//default value of nSplitter is 5 $5v:z   
this("","","",5); rc()Eo50  
} IuN:*P  
0.kQqy~5  
 _YPu  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) KoF_G[m  
{ HCOE'24I  
sSiteURL= sURL; Bq*aP*jv  
sFilePath = sPath; ,o68xfdZVW  
sFileName = sName; [_w;=l0 ;  
this.nSplitter = nSpiltter; S*9qpes-m|  
qdY*y&}"J  
Udl8?EVSz  
} %wk3&EC.  
MFqM 6_  
/KLs+^c5  
public String getSSiteURL() 9n!IdqKN  
{ |a{~Imz{  
return sSiteURL; gkRbb   
} J%SuiT$L&Y  
qEy]Rc%  
jp|1S^b  
public void setSSiteURL(String value) 8AQ@?\Rc"2  
{ V+- ]txu|  
sSiteURL = value; ml\2%07  
} ._A@,]LS}  
,bnrVa(I  
Kh,zp{  
public String getSFilePath() '%\FT-{  
{ dRu|*s  
return sFilePath; e=#'rDm  
} NU{`eM  
ocDAg<wo  
]46#u=y~3  
public void setSFilePath(String value) k< i#agq  
{ LktH*ePO  
sFilePath = value; ccm(r~lhJ  
} s?pd&_kOv3  
KV {J>J1  
l0GsY.~,  
public String getSFileName() :$5$H  
{ 1$1[6 \3v  
return sFileName; 22_%u=p-|  
} hUO&rov3@  
+:jx{*}jo  
3Lw&HtH  
public void setSFileName(String value) GT3 ?)g{Z  
{ 4ht+u  
sFileName = value; RI</T3%~  
} +q-/~G'  
K]s*rPT/,  
,"U_oa3  
public int getNSplitter() ?D8 +wj  
{ 5*P+c(=  
return nSplitter; w_hN2eYo&e  
} 6<>T{2b:(p  
IwJ4K+  
y3{ F\K  
public void setNSplitter(int nCount) ##_Jz5P  
{ 6L4<c+v_  
nSplitter = nCount; B?pNF+?'z  
} T**v!Ls  
} 4Ow0g-{  
IqrT@jgN-  
z [9f  
/* '#Pg:v_  
**Utility.java /.>8e%)  
*/ { M&Vh]  
package NetFox; "2 "gTS  
i?0+f }5<p  
k/]4L!/ T  
public class Utility { ] lONi  
e|2@z-Sp-  
RP|/rd]-k  
public Utility() \#O}K  
{ guc[du  
\Jy/ a-  
}?KfL$@$  
} ]sL)[o  
K#_x.: <J  
//线程睡眠 ecIZ +G)k  
public static void sleep(int nSecond) & Y Y^Bd#  
{ !wNj;ST*  
try{ 'wm :Xa  
Thread.sleep(nSecond); M`u&-6  
} op5G}QZ  
catch(Exception e) Tc.k0n%W:b  
{ BK;Gh0mp  
e.printStackTrace (); {.mP e|  
} i0/RvrLc  
} Pua| Z x  
]~!?(d!J/  
//日志 Al-;-t#Dc  
public static void log(String sMsg) XMpa87\  
{ & c V$`L  
System.err.println(sMsg); , tb\^  
} DITo.PU  
Ae[Na:G+  
{2,vxGi  
public static void log(int sMsg) Z\. n6  
{ _'Rzu'$`  
System.err.println(sMsg); %8hjMds  
} 05PRlz *x=  
} P~d&PhOe  
;:DDz  
/|MHZ$Y9w?  
/* LfsqtQ=J`  
**TestMethod.java mtd ,m  
*/ pEp`Z,p  
package NetFox; 2*)2c[/0F  
K~6,xZlDWM  
rU!QXg]uD  
public class TestMethod { 4#"_E:;PQ  
HY!R|  
ky#5G-X  
public TestMethod() K*id 1YY  
{ ///xx/weblogic60b2_win.exe |^k&6QO5  
try{ (2uF<$7(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); z}z 6Vg  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); dgp1B\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3[F9qDAy  
fileFetch.start(); [@;q#.}Z  
} ,*MA teD  
catch(Exception e){e.printStackTrace ();} (<KFA,  
w 8B SY  
W{W8\  
} 1LZ[i89&%  
~;S  
DV{0|E  
public static void main(String[] args) }huFv*<@'  
{ {'@`: p&3r  
new TestMethod(); a2%xW_e  
} M)6iYA%$  
} B9(@ .  
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