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http断点续传简单实现(java)

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/* 7l7eUy/z  
**SiteFileFetch.java g84~d(\?  
*/ M[R, m_p  
package NetFox; S]9:3~  
import java.io.*; ?Hf^& yo  
import java.net.*; 8S@ ~^D  
@+ Berb  
EFf<| v  
public class SiteFileFetch extends Thread { mh.0% 9`9  
T6Ue\Sp'  
gJ c5Y  
SiteInfoBean siteInfoBean = null; //文件信息Bean mv SNKS  
long[] nStartPos; //开始位置 KHcf P7  
long[] nEndPos; //结束位置 {.H}+@0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |vTirZP  
long nFileLength; //文件长度 .-`7Av+7  
boolean bFirst = true; //是否第一次取文件 K,|Gtaa~  
boolean bStop = false; //停止标志 s3_i5,y  
File tmpFile; //文件下载的临时信息 Z=R>7~H  
DataOutputStream output; //输出到文件的输出流 Trbgg  
=d7lrx+z  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 11X-X  
public SiteFileFetch(SiteInfoBean bean) throws IOException y$*Tbzp  
{ &>@nW!n u  
siteInfoBean = bean; @6 gA4h  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); N ^h,[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0$}+tq+  
if(tmpFile.exists ()) uc=-+*D'I  
{ 0l.+yr}PE  
bFirst = false; W5_t/_EWD  
read_nPos(); 4'Vuhqk  
} Nh]eZ3O  
else a%;$l_wVT:  
{ u~1[nH:  
nStartPos = new long[bean.getNSplitter()]; g}$]K! F  
nEndPos = new long[bean.getNSplitter()]; !z(POK  
} bW3e*O$V  
Bu>srX9f  
)f(#Fn  
;'}1   
}  4rwfY<G  
@w,-T@nAW  
I@+dE V`Lf  
public void run() "]*0)h_  
{ S=krF yFw  
//获得文件长度 `"zX<  
//分割文件 aMZ6C <N  
//实例FileSplitterFetch K}`.?6O  
//启动FileSplitterFetch线程 1reJ7b0  
//等待子线程返回 G:c)e ,pD  
try{ *@cXBav/<  
if(bFirst) b&HA_G4  
{ !ygh`]6V  
nFileLength = getFileSize(); ;|soc:aH  
if(nFileLength == -1) o8 q@rwu3  
{ :~ zK0v"  
System.err.println("File Length is not known!"); 9i yNR!  
} UR1U; k  
else if(nFileLength == -2) 7AV!v`  
{ u{ JAC!  
System.err.println("File is not access!"); ud'r ?QDM  
} f/*Xw{s#  
else NLoJmOi;L7  
{ rm+|xvZ4  
for(int i=0;i<nStartPos.length;i++) 9N5 &N3  
{ !j%vUe;t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @,i:fY  
} a&.8*|w3  
for(int i=0;i<nEndPos.length-1;i++) 3 5B0L.R  
{ 5z5#_*)O  
nEndPos = nStartPos[i+1]; 2o6KVQ  
} ^Ml)g=Fq  
nEndPos[nEndPos.length-1] = nFileLength; 1 q}iUnR  
} fg*IHha  
} p r(:99~3  
B3c rms['  
Cbx/  
//启动子线程 *S:^3{.m=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \[B5j0vV,  
for(int i=0;i<nStartPos.length;i++) &P&M6v+  
{ Zh{Pzyp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 80![aj}z4G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -% 5*c61  
nStartPos,nEndPos,i); Br`Xw^S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &h`s:Y  
fileSplitterFetch.start(); #=OKY@z/  
} (05/}PhB`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2%. A{!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pu0IhDMn  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3-lJ]7OT  
nEndPos = " + nFileLength); }_@*,  
// fileSplitterFetch[nPos.length-1].start(); 9=ns.r  
Xb?P'nD  
?`u Y*+u  
//等待子线程结束 {tOu+zy  
//int count = 0; R',Q)<  
//是否结束while循环 ,=Xr'7w,  
boolean breakWhile = false; QPg QM6  
O:{I9V-=>s  
|XtN\9V.  
while(!bStop) !X` 5  
{ c/^} =t(  
write_nPos(); #i%it  
Utility.sleep(500); CDK0 $W n  
breakWhile = true; ?y>P  
vYKKv%LE  
1 }Tbp_  
for(int i=0;i<nStartPos.length;i++) + Hc[5WL  
{ !)?n n3  
if(!fileSplitterFetch.bDownOver) !0zbWB9  
{ l"W9uS;\T  
breakWhile = false; }/4 AT  
break; E<:XHjm  
} ?k TVC  
} }cn46 L%/  
if(breakWhile) VY<$~9a&1  
break; 58DkVQ6  
FWq+'Gk SV  
WJ<nc+/v:  
//count++; M56^p ,  
//if(count>4) 2RFYnDN  
// siteStop(); ylUxK{  
} IX$dDwY|O>  
p^3 ]Q  
-= H* (M  
System.err.println("文件下载结束!"); yS[:C 2v  
} 0BMKwZg  
catch(Exception e){e.printStackTrace ();} 47|Lk]+O  
} n;@PaE^8=  
s )POtJ<  
+ 0{m(%i  
//获得文件长度 6NPCp/  
public long getFileSize() MCZTeYnx  
{ EcxPbRg  
int nFileLength = -1; <1YINkRz  
try{ (0/,R  
URL url = new URL(siteInfoBean.getSSiteURL()); umaF}}-Q{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '- oS=OrZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); :.e`w#$7  
|]1-ck!  
9]<p  
int responseCode=httpConnection.getResponseCode(); i,r O3J n  
if(responseCode>=400) z#ab V1 Xi  
{ VCSHq&p8  
processErrorCode(responseCode); {F6>XuS=u  
return -2; //-2 represent access is error twv|,kM  
} 48hu=,)81*  
=iW!Mq  
Ebw1 %W KC  
String sHeader; $N'AZY]4]  
cXU8}>qY7  
w#vSZbh  
for(int i=1;;i++) Uy2NZ%rnt  
{ "(zvI>A  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )h6hN"#V5  
//Utility.log(in.readLine()); gHdNqOy c  
sHeader=httpConnection.getHeaderFieldKey(i); Px{Cvc  
if(sHeader!=null) e/Wrm^]y  
{ V T8PV5z  
if(sHeader.equals("Content-Length")) jd8`D6|Z  
{ gqV66xmJ3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *oopdGue  
break; B>Tfyo  
} UF0W%Z  
} O=~8+sa  
else ZKy)F-yX  
break; s~ ||Vv!  
} cyrVz4_a  
} d` %8qLIW  
catch(IOException e){e.printStackTrace ();} ^0)Mc"&{  
catch(Exception e){e.printStackTrace ();} r<VZE bm)  
Oxo?\ :T  
#hG0{_d7  
Utility.log(nFileLength); C))5,aX  
h DpIwzJ  
7=i8$v&GX  
return nFileLength; YXz*B5R  
} 2;Vss<hR4A  
~e*3_l>9  
-FQ!  
//保存下载信息(文件指针位置) hgIqr^N9  
private void write_nPos() H'KCIqo  
{ kt`_n+G  
try{ BIGln`;,f  
output = new DataOutputStream(new FileOutputStream(tmpFile)); E Q 'L"  
output.writeInt(nStartPos.length); )4:K@  
for(int i=0;i<nStartPos.length;i++) Loz5[L  
{ =1Nz* c  
// output.writeLong(nPos); aF*KY<w  
output.writeLong(fileSplitterFetch.nStartPos); sB!#`kh  
output.writeLong(fileSplitterFetch.nEndPos); ?YE'J~0A6  
} -#<6  
output.close(); T8<pb^#  
} .5L|(B=H  
catch(IOException e){e.printStackTrace ();} #&zM.O1Q  
catch(Exception e){e.printStackTrace ();} Yc~(W ue  
} tfB}U.  
(-S<9u-r  
mm}y/dO~}  
//读取保存的下载信息(文件指针位置) O2i7w1t  
private void read_nPos() gJa48 pi  
{ #b~B 0:U  
try{ -55[3=#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _y>mmE   
int nCount = input.readInt(); SeuC7!q{  
nStartPos = new long[nCount]; +cH,2^&  
nEndPos = new long[nCount]; :j(e+A1@  
for(int i=0;i<nStartPos.length;i++) R[_Q}W'HG  
{ jfmHc(fX4  
nStartPos = input.readLong(); a ?D]]0%  
nEndPos = input.readLong(); zT<fTFJ1  
} I=aoP}_  
input.close(); 42/MBP`\Y  
} TF]bmM})0  
catch(IOException e){e.printStackTrace ();} *JnY0xP  
catch(Exception e){e.printStackTrace ();} l5h+:^#M5c  
} X,5}i5'!  
Z2n Jw  
k+9*7y8w  
private void processErrorCode(int nErrorCode) *Bfo"["0.  
{ G5WQTMzf&  
System.err.println("Error Code : " + nErrorCode); `iHyGfm  
} 8^IV`P~2M  
zM+4<k_dH]  
LZ#=Ks  
//停止文件下载 pbCj ^  
public void siteStop() {6 #Qm7s-  
{ j1zrjhXI  
bStop = true; jY;T:C-T  
for(int i=0;i<nStartPos.length;i++) ;X_bDiG$  
fileSplitterFetch.splitterStop(); I+oe{#:.  
[8C|v61Y  
m}UcF oaO  
} T`?7z+2A  
} o*MiKgQ&  
//负责部分文件的抓取 Xr:gm`[  
**FileSplitterFetch.java u+/Uc:XK)  
*/ {c  : 7:  
package NetFox; ]& 8c 45c  
~];r{IU  
rn$G.SMgz  
import java.io.*; Cn"_x  
import java.net.*; y^!>'cdV  
YD3jP}Ym  
yj$$k~@  
public class FileSplitterFetch extends Thread { GB%kxtGD;\  
,NO2{Ha$  
q t(+X  
String sURL; //File URL Hs:0j$  
long nStartPos; //File Snippet Start Position 1d$qr`  
long nEndPos; //File Snippet End Position t1JU_P  
int nThreadID; //Thread's ID sX@}4[)<&  
boolean bDownOver = false; //Downing is over ^ps6\>=0cW  
boolean bStop = false; //Stop identical &Fiesi!tET  
FileAccessI fileAccessI = null; //File Access interface W [*Go  
4,,DA2^!  
%p48=|+  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _sb~eB~<(  
{ 0g 2?  
this.sURL = sURL; Iuyq!R4:7  
this.nStartPos = nStart; ZUyS+60  
this.nEndPos = nEnd; m?< ^b_a}  
nThreadID = id; ~8 B]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 f+ cN'jH E  
}  -uKTEG[  
Ypx5:gm|J  
y Nc@K|  
public void run() z''ejq  
{ j.&Y'C7GOC  
while(nStartPos < nEndPos && !bStop) o%b6"_~%3  
{ /78zs-  
;J@U){R  
KqN;a i,F  
try{ 4U8N7  
URL url = new URL(sURL); uTdx`>M,O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); GE8.{P  
httpConnection.setRequestProperty("User-Agent","NetFox"); u`.3\Geh  
String sProperty = "bytes="+nStartPos+"-"; o)bKs>` U  
httpConnection.setRequestProperty("RANGE",sProperty); SK5_^4  
Utility.log(sProperty); r6eZ-V`4  
<{+U- ^rzR  
w%?Zb[!&  
InputStream input = httpConnection.getInputStream(); 5tI#UBha  
//logResponseHead(httpConnection); zfD@/kU  
&cWC&Ws"  
{wDq*va  
byte[] b = new byte[1024]; +/[L-&,  
int nRead;  bUsX~R-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *rgF[ :  
{ y6dQ4Whv&  
nStartPos += fileAccessI.write(b,0,nRead); -Qn l)JB  
//if(nThreadID == 1) 4VHWoN"U  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VFrp7;z43  
} VA>0Y  
p,V%wGM  
3(Ns1/;?,  
Utility.log("Thread " + nThreadID + " is over!"); )oALB vX  
bDownOver = true; 5hHLC7tT9  
//nPos = fileAccessI.write (b,0,nRead); 3ey.r%n  
} .=)[S5.BVq  
catch(Exception e){e.printStackTrace ();} abAw#XQ8  
} RWRqu }a  
} 1V wcJd  
W ]$/qyc&J  
.Y|wG<E  
//打印回应的头信息 <PFF\NE9  
public void logResponseHead(HttpURLConnection con) q;lR|NOh  
{ (rc 7Cp3  
for(int i=1;;i++) 8(Q|[  
{ [_KV;qS%/  
String header=con.getHeaderFieldKey(i); S n<X   
if(header!=null) m68>`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); B^!-%_q  
Utility.log(header+" : "+con.getHeaderField(header)); -e_|^T"  
else QH,Fw$1  
break; m2H?VY .^K  
} y^e3Gyk  
} J )^F  
9[`c"Pd  
Lu~E5 ,  
public void splitterStop() ^9`|QF  
{ joDqv,iW8  
bStop = true; `M*jrkM]x  
} op@=0d??  
yM}3u4FG  
KYZ#.f@  
} @tJ4^<`P{  
')}itS8  
,J '_Vi  
/* .hM t:BMf*  
**FileAccess.java E]v]fy"  
*//文件访问(定位,写) /N({"G'  
package NetFox; !g`I*ZE+e  
import java.io.*; w=CzPNRHH!  
p>O/H1US;  
<@# g2b  
public class FileAccessI implements Serializable{ Y]=k"]:%  
oB%_yy+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &qK:LHhj  
RandomAccessFile oSavedFile; : h(Z\D_  
long nPos; F\hVunPVx  
6yBd9=3K  
Z ^}[CQ&Am  
public FileAccessI() throws IOException pH2/." zE<  
{ }a/z.&x]V  
this("",0); 'Hzc"<2Y\  
} $hHV Ie]+  
*Ojl@N  
piH0_7qr  
public FileAccessI(String sName,long nPos) throws IOException Q)y5'u qZ  
{ mo3A*|U  
oSavedFile = new RandomAccessFile(sName,"rw"); m?; ?I]`  
this.nPos = nPos; sYo&@~T  
oSavedFile.seek(nPos); 7AS_Aw1L  
} 1hlU 6 =Y  
MRw4?HqB  
?:M4GY" gV  
public synchronized int write(byte[] b,int nStart,int nLen) :h |]j[2p  
{ |V4<eF-0S  
int n = -1; $.t>* Bq  
try{ mBJr*_p  
oSavedFile.write(b,nStart,nLen); D)pTE?@W'  
n = nLen; >_xuXEslUz  
} YF-A8gXS  
catch(IOException e) TpwN2 =  
{ 7R7+jL,  
e.printStackTrace (); 3u/AqL  
} !yVY[  
dA (n,@{  
6-uLK'E  
return n; -%]1q#C>@  
} rQ_]%ies8  
PqL. ^  
jVLJ qWP'!  
} Xz)qtDN|(  
j#2E Q  
u]7wd3(  
/* a??8)=0|}  
**SiteInfoBean.java !V(r p80  
*/ s*_fRf:  
package NetFox; 1og+(m`BL  
G&Dl($  
|`Noj+T47I  
public class SiteInfoBean { (hdu+^Qj=  
SASLeGaV  
jI0gf&v8  
private String sSiteURL; //Site's URL 'e' p`*  
private String sFilePath; //Saved File's Path 7i{(,:  
private String sFileName; //Saved File's Name *Ow2,{Nn  
private int nSplitter; //Count of Splited Downloading File W;cY g.W2  
79c M _O  
Ncsh{.  
public SiteInfoBean() ;9WUt,R  
{//nSplitter的缺省值为5 W7b m}JHn  
//default value of nSplitter is 5 },#7  
this("","","",5); p}h.2)PO  
} : \qapFV  
+&S6se4  
x~R,rb   
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) I#M>b:"t e  
{ j)Ak:l%a  
sSiteURL= sURL; 4bp})>}jB  
sFilePath = sPath; '2i !RT-  
sFileName = sName; rm9>gKN;#  
this.nSplitter = nSpiltter; q^sZP\i,*;  
,c  ^nW  
"OK[uug  
} R3U|{vgl  
#T2J +  
1%*\*z  
public String getSSiteURL() 7(X z%v   
{ GM'yOJo  
return sSiteURL; '7PaJj=Nx  
} G"E_4YkJ  
>;hAw!|#  
i>,AnkI&  
public void setSSiteURL(String value) T}=^D=  
{ :>;F4gGVG  
sSiteURL = value; r~h#  
} J ffaT_"\  
xlJWCA*>  
M /v@C*c  
public String getSFilePath() !rr,(!Ip?O  
{ hL6;n*S=  
return sFilePath; ~gff{Nzk  
} Tn1V+)  
}.E^_`  
,0,FzxX0!  
public void setSFilePath(String value) YfB)TK\W9/  
{ 'UWkJ2:!  
sFilePath = value; cPuXy e  
} [bP^RY:  
`MuX/ [q  
ls:oC},p*  
public String getSFileName() ]q{_i   
{ bI|G %  
return sFileName; o}114X4q;  
} )]FXUz|;  
&`v?oN9$  
UAhWJ$(C  
public void setSFileName(String value) kl.;E{PL  
{ ;]Q6K9.d8  
sFileName = value; bV&9>fC  
} (~zu4^9w  
2<I=xWwFA  
f%@~|:G:  
public int getNSplitter() =dDPQZEin  
{ `sT;\  
return nSplitter; lMGO4U[z  
} m","m  
jL^@;"/XhC  
czD" mI!  
public void setNSplitter(int nCount) {<gv1Yht  
{ >x;\H(g  
nSplitter = nCount; aF^N  Ye  
} 94ruQ/  
} $$NWN?H~  
~>u| 7 M$(  
7GsKD=bl]  
/* ApeqbD5g&  
**Utility.java IoLi7NKw  
*/ s__xBY  
package NetFox; "d$~}=a[  
;un@E:  
z80P5^9  
public class Utility { bc'IoD/  
=b:XL#VA  
EwN{|34C  
public Utility() MVzuE}  
{ f1ANziC;i  
GT<oYrjU  
<z,)4z++  
} ==m[t- 9x  
F/5G~17  
//线程睡眠 Mg`!tFe3  
public static void sleep(int nSecond) Dc-K08c  
{ z eT`kZ  
try{ fF0i^E<  
Thread.sleep(nSecond); T3z ovnR  
} ]5f;Kz)  
catch(Exception e) {V QGfN  
{ OLb s~ >VA  
e.printStackTrace (); ?yef?JI$p  
} r9_ ON|  
} mEd2f^R  
8eS(gKD  
//日志 Fk/I (Q  
public static void log(String sMsg) ZgxB7zl//  
{ tjx8 UgSi  
System.err.println(sMsg); 3?*d v14  
} 2 3PRb<q  
-|m3=#  
+zMPkbP6  
public static void log(int sMsg) #!R>`l(S  
{ }b(h D|e  
System.err.println(sMsg); cr!W5+r  
} Jh E C  
} iX+8!>Q  
JKM(fX+  
+ausm!~6  
/* I </P_:4G  
**TestMethod.java f $Agcy  
*/ "i;.>  
package NetFox; sq_>^z3T  
c]|vg=W  
n;Oe-+oSC  
public class TestMethod { 7 <^+)DsS?  
2 L4[~>  
]H n:c'aT  
public TestMethod() DPzW,aIgv  
{ ///xx/weblogic60b2_win.exe )sm9%|.&  
try{ hc|A:v)]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); NlEyT9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~{Iw[,MJ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ZR}v_]l^  
fileFetch.start(); eA!Z7 '  
} .A< HM}   
catch(Exception e){e.printStackTrace ();} '\#q7YjaL  
IEy$2f>Ns  
YP02/*'  
} aA|{r/.10K  
%[p*6&V  
`}),wBq  
public static void main(String[] args) zVS{X=u  
{ g9pKoi|\E  
new TestMethod(); <\^o  
} crIF5^3Yby  
} 9xK>fM&u  
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