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http断点续传简单实现(java)

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/* do>wwgr  
**SiteFileFetch.java [<@.eH$hU/  
*/ ;@oN s-  
package NetFox; &OH={Au  
import java.io.*; Fww :$^_ k  
import java.net.*; W:pIPDx1=!  
pOIJH =#  
s{ *[]!  
public class SiteFileFetch extends Thread { k5'Vy8q  
p$] 3'jw  
o6.^*%kM'  
SiteInfoBean siteInfoBean = null; //文件信息Bean W*2BT z  
long[] nStartPos; //开始位置 [M=7M}f;  
long[] nEndPos; //结束位置 QTk}h_<u  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 GjvOM y  
long nFileLength; //文件长度 VA#"r!1  
boolean bFirst = true; //是否第一次取文件 I&x=;   
boolean bStop = false; //停止标志 9y"@(  
File tmpFile; //文件下载的临时信息 i9,ge Q7d  
DataOutputStream output; //输出到文件的输出流 p8Qk 'F=h  
KW pVw!  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) k_rt&}e+Gi  
public SiteFileFetch(SiteInfoBean bean) throws IOException Swig;`  
{ t-tg-<  
siteInfoBean = bean; 8p 'L#Q.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); g}1B;zGf  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j8 ^Iz  
if(tmpFile.exists ()) 52Z2]T c ,  
{ LTQ"8  
bFirst = false; &]|?o_p3W  
read_nPos(); m[~y@7AK<  
} P@V0Mi),  
else K0|FY=#2y  
{ W}@c|d $`  
nStartPos = new long[bean.getNSplitter()]; aC8} d  
nEndPos = new long[bean.getNSplitter()]; 65JF`]  
} V ]lLw)  
KQ% GIz x  
8Fz#A.%P  
z]_wjYn Z  
} {EB;h\C  
s+$ Q}|?u  
dy%;W%  
public void run() B9jC?I |`  
{ vc;$-v$&  
//获得文件长度 B" 1c  
//分割文件 yg<R=$n,Q  
//实例FileSplitterFetch rr],DGg+B]  
//启动FileSplitterFetch线程 0d)M\lG  
//等待子线程返回 IL#"~D?  
try{ wDal5GJp  
if(bFirst) l[0RgO*S  
{ 2lH&  
nFileLength = getFileSize(); nS }<-s  
if(nFileLength == -1) Fo5FNNiID  
{ {HltvO%8  
System.err.println("File Length is not known!"); XpB_N{v9w  
} 5H<m$K4z  
else if(nFileLength == -2) 6 $4[gcL'  
{ y}" O U  
System.err.println("File is not access!"); l*Gvf_UH  
} M2,l7  
else -A^_{4X  
{ %S960  
for(int i=0;i<nStartPos.length;i++) t&C1Oo}=3  
{ _7Ju  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %} SrL*  
} > PRFWO  
for(int i=0;i<nEndPos.length-1;i++) ;#W2|'HD  
{ p_gm3Q  
nEndPos = nStartPos[i+1]; AUG#_HE]k  
} c<:-T  
nEndPos[nEndPos.length-1] = nFileLength; t6 "%3#s  
} r= `Jn6@  
} ^1I19q  
|.: q  
RB7tmJ c  
//启动子线程 q_[o" wq/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]nn98y+  
for(int i=0;i<nStartPos.length;i++) !Iy_UfW  
{ V(I8=rVH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $Vg>I>i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), EU/C@B2*Dl  
nStartPos,nEndPos,i); C_}]`[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nV|EQs4(  
fileSplitterFetch.start(); mp1@|*Sn  
} Uiw2oi&_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HAdg/3Hw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?=sDM& '  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :%=Xm   
nEndPos = " + nFileLength); @Md/Q~>  
// fileSplitterFetch[nPos.length-1].start(); yLvDMPj  
<`=j^LU  
UERLtSQ  
//等待子线程结束 .5_2zat0H  
//int count = 0; 2`K=Hby  
//是否结束while循环 gh]cXuph  
boolean breakWhile = false; ZPLm]I\]  
AofKw  
SwGx?U  
while(!bStop) g wRZ%.Cn  
{ S&wMrQ  
write_nPos(); W' VslZG  
Utility.sleep(500); 6P l<'3&  
breakWhile = true; /hR&8 `\\  
,?%Zc$\LW  
9s q  
for(int i=0;i<nStartPos.length;i++) Rh{f5-  
{ kS);xA8s]  
if(!fileSplitterFetch.bDownOver) l ukB8  
{ eu-*?]&Di  
breakWhile = false; Dw.J2>uj  
break; -`h)$&,  
} H/ HMm{4  
} EI%89i`3^  
if(breakWhile) rglXs  
break; gPI ?C76  
K($Npuu]  
6<QQ@5_  
//count++; @Cyvf5|bL  
//if(count>4) 4xje$/_d  
// siteStop(); *w\W/Y  
} $Ds2>G4c  
*L^,|   
77f9(~ZnT  
System.err.println("文件下载结束!"); .|70;  
} i[3'ec3  
catch(Exception e){e.printStackTrace ();} [}=B8#Jl-C  
} IOmfF[  
K+3=tk]W9u  
+I|vzz`ZVr  
//获得文件长度 2HA:"v8  
public long getFileSize() hL{KRRf>  
{ tS=(}2Q  
int nFileLength = -1; ;*Et[}3  
try{ "<1{9  
URL url = new URL(siteInfoBean.getSSiteURL()); /(*q}R3Kfo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }&J q}j  
httpConnection.setRequestProperty("User-Agent","NetFox"); :crW9+  
0'C1YvF  
dR,fXQm  
int responseCode=httpConnection.getResponseCode(); 29.h91  
if(responseCode>=400) @RKryY)  
{ z Rr*7G  
processErrorCode(responseCode); #)O6 5GI  
return -2; //-2 represent access is error aX'*pK/-  
} sDlO#  
%P|/A+Mg"  
Z@!+v 19^  
String sHeader; mz0X3  
/nA{#HY  
YNF k  
for(int i=1;;i++) BW4J>{  
{ htF] W|z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ggR.4&<  
//Utility.log(in.readLine()); gjDHo$  
sHeader=httpConnection.getHeaderFieldKey(i); HIZe0%WPw  
if(sHeader!=null) Kn1a>fLaJ_  
{ E ~<JC"]  
if(sHeader.equals("Content-Length")) rjYJs*#  
{ 0x@ mZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); OQJ6e:BGt  
break; q@8*Xa>  
} jQB9j  
} Tyx_/pJT  
else H**Xu;/5@  
break; s.C_Zf~3  
} &V/Mmm T  
} *z8\Lnv~k  
catch(IOException e){e.printStackTrace ();} k5pN  
catch(Exception e){e.printStackTrace ();} %* }(}~  
0\P1; ak%  
Ad_h K O  
Utility.log(nFileLength); %Q|Atgp  
zK@@p+n_#.  
HG^'I+Yn  
return nFileLength; vXje^>_6  
} `b$.%S8uj=  
!+v$)3u9  
2BwO!Y[  
//保存下载信息(文件指针位置) ISvpQ 3{)s  
private void write_nPos() fNFY$:4X  
{ }pkzH'$HJ  
try{ wf<M)Rs|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }BP;1y6-r  
output.writeInt(nStartPos.length); KbeC"mi  
for(int i=0;i<nStartPos.length;i++) Qvhl4-XjZa  
{ H/M@t\$Dc  
// output.writeLong(nPos); cbTm'}R(G  
output.writeLong(fileSplitterFetch.nStartPos); PdWx|y{%  
output.writeLong(fileSplitterFetch.nEndPos); 5=ryDrx  
} >4CbwwMA  
output.close(); _oeS Uzq.  
} gg2( 5FPP  
catch(IOException e){e.printStackTrace ();} w\O;!1iU  
catch(Exception e){e.printStackTrace ();} 4o[{>gW  
} sfl<qD+?  
=dN@Sa/  
N;`n@9BF  
//读取保存的下载信息(文件指针位置) 8Zd]wYO  
private void read_nPos() =T7.~W  
{ Y.p;1"  
try{ oEpFuWp%A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _H@DLhH|=  
int nCount = input.readInt(); GZIa 4A  
nStartPos = new long[nCount]; sFRQe]zCcP  
nEndPos = new long[nCount]; u>vL/nI  
for(int i=0;i<nStartPos.length;i++) H<+TR6k<  
{ Xsa].  
nStartPos = input.readLong(); cw <l{A  
nEndPos = input.readLong(); 4o5t#qP5$S  
} Jln:`!#fDf  
input.close(); j#4kY R{  
} o ^uA">GH  
catch(IOException e){e.printStackTrace ();} 1?l1:}^L  
catch(Exception e){e.printStackTrace ();} U]rRQ d/:;  
} do'GlU oMC  
'LDQgC*%  
\s\?l(ooq"  
private void processErrorCode(int nErrorCode) 4#Jg9o   
{ O;3>sLgc  
System.err.println("Error Code : " + nErrorCode); p6S8VA  
} =7UsVn#o  
^S; -fYW2  
cFXp  
//停止文件下载 [dz _R  
public void siteStop() $%f&a3#  
{ ~a2}(]  
bStop = true; 5[0?g@aO  
for(int i=0;i<nStartPos.length;i++) w,D+j74e$  
fileSplitterFetch.splitterStop(); j1<Yg,_.p  
CAf6:^0  
&UFZS94@r  
} ~wdGd+ez  
} #AY&BWS$  
//负责部分文件的抓取 gjlx~.0d  
**FileSplitterFetch.java !5!<C,U  
*/ {{!-Gr  
package NetFox; Q+{n-? :  
%(Icz ?  
);YDtGip J  
import java.io.*; 1xvu<|F  
import java.net.*; r.U`Kh]K  
Q,Eo mt  
|w3M7;~eF  
public class FileSplitterFetch extends Thread { gRzxLf`K  
VIbq:U  
N2o7%gJw  
String sURL; //File URL /gas2k==^  
long nStartPos; //File Snippet Start Position \Oo Wo  
long nEndPos; //File Snippet End Position %a7$QF]  
int nThreadID; //Thread's ID izR"+v  
boolean bDownOver = false; //Downing is over ~}Pfu  
boolean bStop = false; //Stop identical % ] U  
FileAccessI fileAccessI = null; //File Access interface vP,n(reM  
7xR\kL.,  
e'<)V_  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "J1 4C9u   
{ "r2 r   
this.sURL = sURL; 2fS:- 8N  
this.nStartPos = nStart; vih9 KBT  
this.nEndPos = nEnd; W%w~ah|/]  
nThreadID = id; 0*v2y*2V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Gq P5Kx+=  
} $:^td/p J  
Ho]su?  
;AG()NjOO:  
public void run() 19] E 5'AI  
{ W@esITr  
while(nStartPos < nEndPos && !bStop) +w~oH=  
{ Uw:"n]G]D?  
 0+8e,  
G+m }MOQP7  
try{ MqMQtU9w  
URL url = new URL(sURL); z(~_AN M4,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E*lxVua  
httpConnection.setRequestProperty("User-Agent","NetFox"); moE2G?R  
String sProperty = "bytes="+nStartPos+"-"; eJX#@`K  
httpConnection.setRequestProperty("RANGE",sProperty); !'O@2{?B  
Utility.log(sProperty); Vt ohL+  
1E$|~   
uw8f ~:LT  
InputStream input = httpConnection.getInputStream(); !`r$"}g  
//logResponseHead(httpConnection); )M^ gT}M  
]_$[8#kg  
w2'5#`m  
byte[] b = new byte[1024]; 5-A\9UC*@  
int nRead; & nK<:^n  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qJw_  
{ y_[vr:s5pG  
nStartPos += fileAccessI.write(b,0,nRead); I`#JwMU;m  
//if(nThreadID == 1) J~- 4C)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  AOx[  
} " Yy n/  
t`QENXA}  
Xnh8e  
Utility.log("Thread " + nThreadID + " is over!"); ##ANrG l  
bDownOver = true; i@'dH3-kO  
//nPos = fileAccessI.write (b,0,nRead); S]{oPc[7  
} K> e7pu  
catch(Exception e){e.printStackTrace ();} ;n},"&  
} sR8"3b<qA  
} 3 gf1ownC  
g\AY|;T  
M3Kfd  
//打印回应的头信息 b`_Q8 J  
public void logResponseHead(HttpURLConnection con) j+YJbL v  
{ ,z?':TZ  
for(int i=1;;i++) A2Tw<&Tw(  
{ ,u!sjx  
String header=con.getHeaderFieldKey(i); aQ~s`^D  
if(header!=null) D)Dr__x  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); wA.\i  
Utility.log(header+" : "+con.getHeaderField(header)); MO]&bHH7;  
else nj4/#W  
break; dqAw5[qMJ  
} eDB;cN  
} w*Ihk)  
"7`<~>9t.  
.|=\z9_7S8  
public void splitterStop() &.ACd+Cd  
{ <-0]i_4sK  
bStop = true; azU"G(6y?+  
} Y^]rMK/;  
O H7FkR  
=w^M{W.w  
}  S[QrS 7  
E)3NxmM#  
)}ROLe  
/* (iGTACoF  
**FileAccess.java B?wq=DoG  
*//文件访问(定位,写) 2+O'9F_v  
package NetFox; We z 5N  
import java.io.*; O'~+_ykTl  
hzC>~Ub5  
Vz[C=_m  
public class FileAccessI implements Serializable{ U<-D(J  
CH/rp4NeSy  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^W@5TkkBQq  
RandomAccessFile oSavedFile; "h ^Z  
long nPos; aN=B]{!  
Er[A X.3  
J-4:H gx  
public FileAccessI() throws IOException 'W#D(l9nI  
{ 1nOCQ\$l  
this("",0); bN88ua}k{  
} |Ds=)S" K  
A(N4N  
(9h`3#  
public FileAccessI(String sName,long nPos) throws IOException &~w}_Fjk  
{ BluVmM3Vj  
oSavedFile = new RandomAccessFile(sName,"rw"); 9{uO1O\  
this.nPos = nPos; P }uOJVQ_  
oSavedFile.seek(nPos); $wU\Js`/S]  
} u2[w#   
%K QQ,{ b  
d5l UGRg  
public synchronized int write(byte[] b,int nStart,int nLen) QdC<Sk!G  
{ a}u Sm/S  
int n = -1; { BHO/q3  
try{ PxE3K-S)G  
oSavedFile.write(b,nStart,nLen); \|ao`MMaD<  
n = nLen; v.ui!|c  
} bu"!jHPB  
catch(IOException e) a'z7(8$$  
{ &VcV$8k  
e.printStackTrace (); 1i ] ^{;]  
} FCn_^l)EA  
Tb-F]lg$  
.}*" Nv  
return n; wvPk:1wD5  
} i 3SHg\~Z  
;S*}WqP,  
m#F`] {  
} 9)=ctoZ'  
ei{eTp4HpV  
 f V(J|  
/* 8KNZ](Dj  
**SiteInfoBean.java cs'{5!i]  
*/ 4'Zp-k?5`  
package NetFox; d`6 ' Z  
V470C@  
+t;7tQDVB  
public class SiteInfoBean { Xs?o{]Fe  
"wHFN>5B  
~3 bPIg7D  
private String sSiteURL; //Site's URL E+JqWR5  
private String sFilePath; //Saved File's Path :/Qq@]O>  
private String sFileName; //Saved File's Name ]$_NyAoBb  
private int nSplitter; //Count of Splited Downloading File kSh( u  
?F;8Pa/  
! v0LBe4  
public SiteInfoBean() /FJu)H..U  
{//nSplitter的缺省值为5 C>w|a  
//default value of nSplitter is 5 = 9]~ yt  
this("","","",5); )>- =R5ZV  
} \'bzt"f$j  
O0y_Lm\  
09Cez\0  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0K2`-mL  
{ *D3/@S$B  
sSiteURL= sURL; tNX|U:Y*  
sFilePath = sPath; >e"#'K0?\  
sFileName = sName; jalg5`PU0  
this.nSplitter = nSpiltter; @|%2f@h  
t`mV\)fa  
Wiu"k%Qsh  
} U`m54f@U  
}AH] th  
?1eK#Z.  
public String getSSiteURL() 7Rt9od< )!  
{ >oe]$r  
return sSiteURL; J9[r|`gJ(  
} :[!j?)%>  
abLnI =W`  
e@OX_t_  
public void setSSiteURL(String value) {8%a5DiM  
{ w*JGUk  
sSiteURL = value; $ DSZO!pB  
} Q)[C?obd v  
> "=>3  
J6aef ^>  
public String getSFilePath() & 9 ?\b7  
{ w)Qp?k d  
return sFilePath; 2('HvH]k  
} Hg$lXtn]  
w G<yBI0  
46&/gehr  
public void setSFilePath(String value) NPe%F+X  
{ <HVt V9R  
sFilePath = value; EJNU761  
} >s?S+W[L  
:zF,A,)  
'y3!fN =h  
public String getSFileName() .xWC{}7[  
{ OH(waKq2I  
return sFileName; +&2%+[nBZ  
} =$Nq   
e;}7G  
Ak"m 85B  
public void setSFileName(String value) KNIn:K^/  
{ 5,6"&vU,  
sFileName = value; [ ~&/s:Vvo  
} ah+iZ}E%  
wx0j(:B]  
X*@dj_,  
public int getNSplitter() 9c :cw  
{ d,n 'n  
return nSplitter; &@Be2!%'9K  
} Y\?"WGL)p  
>e[i5  
(jl D+Y_  
public void setNSplitter(int nCount) 6MMOf\   
{ BeoDKdAwY  
nSplitter = nCount; JHTSUq  
} Hn+~5@.  
} !NvI:C_4|  
l3I:Q^x@  
r:ptQo`1-  
/* >_"an~Ss  
**Utility.java $6iX   
*/ 2)HuZda  
package NetFox; D!-g&HBTC  
 DwE[D]7o  
T !WT;A  
public class Utility { AogVF  
!\.pq  2  
jQ^|3#L\  
public Utility() R3&Iu=g  
{ wHMX=N1/  
DjQFi  
'=8d?aeF  
} MXNFlP  
uH- l%17  
//线程睡眠 LR.<&m%~.  
public static void sleep(int nSecond) Fgh_9S9J  
{ A1>OY^p3%  
try{ Oso#+  
Thread.sleep(nSecond); .jT#:_  
} c?[I?ytl  
catch(Exception e) MH9q ;?.J  
{ ;LSANr&  
e.printStackTrace (); 1+{{EOZ4  
} %oa-WmWm  
} *Y7u'v  
W_(j3pV?Ml  
//日志 E GU 0)<  
public static void log(String sMsg) X296tA>C`  
{ hxd`OG<gF  
System.err.println(sMsg); 94.DHZqh  
} DJ [#5h5  
BdblLUGK#  
;d"F%M y  
public static void log(int sMsg) Y}|X|!0x  
{ " h~Z u  
System.err.println(sMsg); CiLg]va   
} `1{ZqRFQ  
} F]]]y5t  
/,&<6c-Q@W  
=O_4|7Zl  
/* `l){!rg8IC  
**TestMethod.java KD7dye  
*/ Tg)| or/ %  
package NetFox; O6a<`]F  
wX5tp1 ?1J  
ipgC RHE  
public class TestMethod { j8{i#;s!"  
qqr?!vem6  
f:|1_j  
public TestMethod() 6J6BF%  
{ ///xx/weblogic60b2_win.exe oiT[de\S  
try{ j2.|ln"!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {Y=WW7:Qx  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); YPK(be_|I  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =llvuUd\n  
fileFetch.start(); pF:$  ko  
} 9gEwh<  
catch(Exception e){e.printStackTrace ();} ?; +1)>{  
)E@.!Ut4o  
JNYFD8J~  
} >#~& -3  
>j(_[z|v3  
cr?Q[8%t1  
public static void main(String[] args) (\hx` Yh=>  
{ 7#ibN!  
new TestMethod(); q#ClnG*  
} %D}kD6=  
} aweV#j(y  
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