http断点续传简单实现（java)

/* 4Eh 2sI  
**SiteFileFetch.java o, e y.  
*/ |r*btyOJk  
package NetFox; FT'_{e!M  
import java.io.*; 6v7H?4  
import java.net.*; `k~.>#  
Oo{+W5[  
1jU<]09.  
public class SiteFileFetch extends Thread { *gRg--PY%  
2Eg*Yb 1  
;4<CnC**  
SiteInfoBean siteInfoBean = null; //文件信息Bean nHxos`Qx  
long[] nStartPos; //开始位置 $c4Q6w  
long[] nEndPos; //结束位置 Ek\fx*Lz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c]:sk[u  
long nFileLength; //文件长度 F4+mkB:w*7  
boolean bFirst = true; //是否第一次取文件 ,|SO'dG  
boolean bStop = false; //停止标志 OM5"&ZIZb  
File tmpFile; //文件下载的临时信息 C 9IKX  
DataOutputStream output; //输出到文件的输出流 6FPGQ0q  
WbZ{) i  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -kY7~yS7  
public SiteFileFetch(SiteInfoBean bean) throws IOException G!},jO*"  
{ Oq~>P!=  
siteInfoBean = bean; jR
<yV  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]Cd1&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); c|q!C0X[  
if(tmpFile.exists ()) @7xb/&N  
{ IxC/X5Mp^q  
bFirst = false; }}Ah-QU  
read_nPos(); seWYY $$  
} ]Hk8XT@Q+  
else <4s$$Uw}6%  
{ OoOKr  
nStartPos = new long[bean.getNSplitter()]; 5 OR L  
nEndPos = new long[bean.getNSplitter()]; !Irmc*;QE  
} 9hG)9X4  
jSbO1go#  
pVe@HJy6G  
pjr,X+6o  
} yP2[!vYw  
}5dYmny  
:_v/a+\n  
public void run() SpbOvY=>  
{ O)C y4[  
//获得文件长度 #iD5& klo\  
//分割文件 UKyOkuY:w  
//实例FileSplitterFetch rQT@:$)  
//启动FileSplitterFetch线程 0KqGJ:Ru  
//等待子线程返回 '/+l\.z"&  
try{ 4~-"k{Xt  
if(bFirst) !FOPFPn  
{ VQE8hQ37  
nFileLength = getFileSize(); z:f[<`,GT  
if(nFileLength == -1) tK)E*!  
{ *k'D%}N:  
System.err.println("File Length is not known!"); w6>'n }  
} NikY0=i  
else if(nFileLength == -2) Q`ERI5b6  
{ c]jK Y<  
System.err.println("File is not access!"); y05(/NH>  
} pUby0)}t  
else m#Rgelhk.  
{ h,B ]5Of  
for(int i=0;i<nStartPos.length;i++) q%8%J'Fro  
{ TTcMIMyLT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -+4:} sD  
} ($:s}_<>s  
for(int i=0;i<nEndPos.length-1;i++) g+BW~e)  
{ RE/'E?G  
nEndPos = nStartPos[i+1]; `
oN~  
} w^tNYN,i  
nEndPos[nEndPos.length-1] = nFileLength; lC&U9=
7W  
} $/;:Xb=q  
} 9?B}CCE<LR  
@f442@_4  
f h05*]r  
//启动子线程 IT& U%hw  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; n1K"VjZk  
for(int i=0;i<nStartPos.length;i++) g(xuA^~J  
{ w J FEua  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5]cmDk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [?uiM^&  
nStartPos,nEndPos,i); ,Zs:e.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); GKdQ  
fileSplitterFetch.start(); OI;0dS  
} yQb^]|XG  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v3 4!rL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7eb^^a?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %g7 !4  
nEndPos = " + nFileLength); G]5m@;~l5  
// fileSplitterFetch[nPos.length-1].start(); TV)b
X  
mmP>Ji  
A-<\?13uW  
//等待子线程结束 vfAR^*7e  
//int count = 0; y7aBF13Kl  
//是否结束while循环 `Q?rQ3A}  
boolean breakWhile = false; -U;2 b_  
$ ;cZq  
xVHZZ?e  
while(!bStop) VS0 &[bl  
{ 6W&huIQ[  
write_nPos(); --E_s/  
Utility.sleep(500); 1~\YJEsb}d  
breakWhile = true; u50 o1^<X  
27q9zi!Q  
xab1`~%K  
for(int i=0;i<nStartPos.length;i++) b:Oa4vBa  
{ j4H]HGHv  
if(!fileSplitterFetch.bDownOver) LwIl2u*  
{ EhDKh\OY5  
breakWhile = false; /bm$G"%d  
break; y]$%>N0vLX  
} Dz$GPA   
} U{(B)dFTH  
if(breakWhile) urmx
})=  
break; !v(j#N< m  
C5mq@$6  
mX))*e4k  
//count++; #DjSS.iW  
//if(count>4) M qq/k J  
// siteStop(); -Z)j"J  
} )P   
Htd-E^/
 
Rn6;@Cw  
System.err.println("文件下载结束！"); "
HI&dC  
} guJS;VC6U  
catch(Exception e){e.printStackTrace ();} QiBo]`)%  
} BUR96YN.  
Wt=QCutt  
M6J~%qF^  
//获得文件长度 . 7WNd/WG  
public long getFileSize() L{_Q%!h3]  
{ LbX>@2(&  
int nFileLength = -1; R7%' vZk  
try{ %Wy$m?gD  
URL url = new URL(siteInfoBean.getSSiteURL()); Cx(|ZD^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 82ay("ZY  
httpConnection.setRequestProperty("User-Agent","NetFox"); ()K,~  
1#LXy%^tO  

._2#89V  
int responseCode=httpConnection.getResponseCode(); 1&
%6sZN  
if(responseCode>=400) "b)Y5[nW  
{ v
sc)EM ]  
processErrorCode(responseCode); aH7i$U&  
return -2; //-2 represent access is error nn'a`N  
} 1b*
Me'  
j>f  
[-}LEH1[p  
String sHeader; ' lt5|  
2JY]$$K7  
]o}g~Xn  
for(int i=1;;i++) :
E ]Ys  
{ hKa<9>MI`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); kY d'6+m  
//Utility.log(in.readLine()); :iW+CD)j  
sHeader=httpConnection.getHeaderFieldKey(i); ~*aPeJ  
if(sHeader!=null) !EO
*xxQ  
{ f;os\8JdM  
if(sHeader.equals("Content-Length")) s|*0cK!K^  
{ )IN!CmpN  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &/XRiK1"0  
break; GQ=Zp3[  
} OCR`1  
} 'T G4
3^  
else }G8gk"st  
break; z4GcS/3K  
} )UBU|uYR\  
} %eK=5Er jx  
catch(IOException e){e.printStackTrace ();} Sg#$ B#g  
catch(Exception e){e.printStackTrace ();} SrlTwcD  
&>Zm gz  
1<gY  
Utility.log(nFileLength); \<k5c-8Hb  
gumT"x .^  
QH~;B[->  
return nFileLength; +fh@m h0[  
} c3S}(8g5.  
Tp vq5Cz  
K&T[F!  
//保存下载信息（文件指针位置） wm1`<r^M.  
private void write_nPos() *`D}voU  
{ IXjFK  
try{ "cJ))v-'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^qB a~  
output.writeInt(nStartPos.length); 9]u=b\fzZ  
for(int i=0;i<nStartPos.length;i++) %x}iEqkU  
{ BQ8vg8e]B  
// output.writeLong(nPos); is?#wrV=K  
output.writeLong(fileSplitterFetch.nStartPos); jh7-Fl
`  
output.writeLong(fileSplitterFetch.nEndPos); rV6&:\  
} :#_Ne?\a@  
output.close(); S F:>dneB  
} il8n K  
catch(IOException e){e.printStackTrace ();} ,|5|aVfh  
catch(Exception e){e.printStackTrace ();} Ez()W,6]g  
} ]iI2  
%5g(|Y]  
S10"yhn(-t  
//读取保存的下载信息（文件指针位置） :%&|5Y
tb  
private void read_nPos() )P13AfK  
{ j p"hbV  
try{ AW{"9f4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .wH`9aq;5@  
int nCount = input.readInt(); <'y}y}%  
nStartPos = new long[nCount]; rdQKzJiX=U  
nEndPos = new long[nCount]; 7+(on  
for(int i=0;i<nStartPos.length;i++) `kE ;V!n?  
{ 3
8<Z=#S  
nStartPos = input.readLong(); DxM$4  
nEndPos = input.readLong(); KM-d8^\:  
} 1>~bzXY#  
input.close(); 0H9UM*O  
}
G4&vrM,f  
catch(IOException e){e.printStackTrace ();} e\8|6<o[  
catch(Exception e){e.printStackTrace ();} +aY]?]  
} k-V3l  
&\Ze<u  
]Rk4"i  
private void processErrorCode(int nErrorCode) ` x|=vu-  
{ ;?h+8Z/{  
System.err.println("Error Code : " + nErrorCode); K*!qt(D&  
} `;~A  
QsemN7B"<  
*F:)S"3_~e  
//停止文件下载 PTS dW~3  
public void siteStop() MpNgp)%>  
{ 8-||Nh  
bStop = true; uM"_3je{W2  
for(int i=0;i<nStartPos.length;i++) DXI{ jalL  
fileSplitterFetch.splitterStop(); `erKHZ]S  
C@o8C%o  
#Sc9&DfX  
} i)!2DXn  
} z=FOymvC  
//负责部分文件的抓取 mb\"qD5  
**FileSplitterFetch.java Svicw`uX0  
*/ -~_[2u^3  
package NetFox; 969Y[XQ  
{P{h|+;  
Tr@|QNu  
import java.io.*; wU}%]FqtZ=  
import java.net.*; &7J-m4BI  
@sdHB./  
+0l-zd\  
public class FileSplitterFetch extends Thread { Q\W?qB_  
{*PbD;/f  
jLM}hwJ8  
String sURL; //File URL ` n#Db  
long nStartPos; //File Snippet Start Position :L+%5Jq  
long nEndPos; //File Snippet End Position 9)?_[|2  
int nThreadID; //Thread's ID 8a8CY,n{  
boolean bDownOver = false; //Downing is over 31GqWN`>$  
boolean bStop = false; //Stop identical M!Ua/g=u  
FileAccessI fileAccessI = null; //File Access interface \=qZ),bU@  
1c\KRK4  
C0gY  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException e"(SlR  
{ c5em*qCw$  
this.sURL = sURL; |Vo{ {
)  
this.nStartPos = nStart; VPr`[XPXb  
this.nEndPos = nEnd; |!q,J  
nThreadID = id; elGwS\sw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -=WQed}  
} s-801JpiJ  
LrH"d  
L$z(&%Nx  
public void run() A\w"!tNM|  
{ h!mx/H
x  
while(nStartPos < nEndPos && !bStop) ]3Y J a  
{ 5W!#,jz  
&[z<p  
WYN0,rv1:+  
try{ >ZwDcuJ~Lz  
URL url = new URL(sURL); X> T_Xc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `iNH`:[w  
httpConnection.setRequestProperty("User-Agent","NetFox"); Kw7uUJR  
String sProperty = "bytes="+nStartPos+"-"; [G",Yky  
httpConnection.setRequestProperty("RANGE",sProperty); 3;JF5e\?x  
Utility.log(sProperty); .TM. v5B  
Y#t9DhzFWo  
X#>:9  
InputStream input = httpConnection.getInputStream(); $@HW|Y  
//logResponseHead(httpConnection); eg1Mdg\a  
FnPn#Cv>*  
Itz[%Dbiq9  
byte[] b = new byte[1024]; YuUJgt .1  
int nRead; Ea)=K'Pz  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7J;\&q'  
{ |ju+{+  
nStartPos += fileAccessI.write(b,0,nRead); <Uy $b4h  
//if(nThreadID == 1) M%YxhuT0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vW-o%u*  
} n-u HKBq  
$ ~%w21?&  
2~l+2..  
Utility.log("Thread " + nThreadID + " is over!"); xOx=Z\ c  
bDownOver = true; x=03WQ8  
//nPos = fileAccessI.write (b,0,nRead); t3b M4+n  
} &`IJ55Z-)  
catch(Exception e){e.printStackTrace ();} `x`zv1U  
} .lAPlJOO  
} bA1O]:`  
>a;LBQ0  
)UtK9;@"  
//打印回应的头信息 I|l5e2j  
public void logResponseHead(HttpURLConnection con) 9vP#/-g  
{ tlM >=s'T  
for(int i=1;;i++) TkR#Kzv380  
{ cGyR_8:2cv  
String header=con.getHeaderFieldKey(i); Nwo*tb:  
if(header!=null) \UP=pT@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2fgYcQ8`  
Utility.log(header+" : "+con.getHeaderField(header)); Zb7%$1)L~  
else p}Um+I=1  
break; B7wzF"  
} 29^(weT"]  
} `MHixQ;j  
Q@uWh:  
Ob/i_  
public void splitterStop() }9 ]7V<  
{ :PK2! 0nK  
bStop = true; "A*;V  
} {
"2Hv;x  
Mh2Zj  
{oS/Xa  
} r~G amjS  
>`
l^ C  
1En:QQ4/  
/* UIkO_/}  
**FileAccess.java *a^wYWa  
*//文件访问(定位，写) <iBn-EG l>  
package NetFox; :Q,~Nw>  
import java.io.*; CTe!jMZ=  
;Y,zlq2  
vJ{F)0 K  
public class FileAccessI implements Serializable{ F1S0C>N?5  
1(pv3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 rp4{lHw>C/  
RandomAccessFile oSavedFile; (f2r4Io|}  
long nPos; _F(Np\%_  
^E_chx-e}  

gCF
9XKW  
public FileAccessI() throws IOException
u_}UU 2  
{ bXeJk]#y  
this("",0); 86eaX+F  
} 5|7<ZL3  
k(M"
k!M  
O)ose?Z  
public FileAccessI(String sName,long nPos) throws IOException \<hHZS  
{ +4p=a [  
oSavedFile = new RandomAccessFile(sName,"rw"); ,|GjrT{vf  
this.nPos = nPos; 4s9."
)G  
oSavedFile.seek(nPos); If]rg+|U  
} HRyhq;C  
p({Lp}'  
6XHM`S  
public synchronized int write(byte[] b,int nStart,int nLen) 0Y'ow=8M  
{ `t\\O  
int n = -1; d+vAm3.Dg  
try{ xSm~V3bc  
oSavedFile.write(b,nStart,nLen); &JYkh >  
n = nLen;
BnfuI  
} F2MC)&#  
catch(IOException e) .<E7Ey#  
{ 1JJ1!& >  
e.printStackTrace (); $ce*W9`  
} Ly/  
{>PEl;,-  
B873UN  
return n; @LFB}B  
} t&p I  
R)4,f~@"  
>Q'*~S@v3  
} |#{ i7>2U  
;>/yY]F7  
A^$xE6t  
/* >JA>np  
**SiteInfoBean.java ujl?!  
*/ vRn]u57O  
package NetFox; ~W={"n?=  
`DE_<l  
+]( #!}oH  
public class SiteInfoBean { W9oWj7&h  
Sb?Ua*(L:  
\3]O?'  
private String sSiteURL; //Site's URL 86 9sS
  
private String sFilePath; //Saved File's Path =HB(N|9_d  
private String sFileName; //Saved File's Name {2QP6XsJ  
private int nSplitter; //Count of Splited Downloading File V2xvuDHI  
a#G3dY>  
.XkD2~;  
public SiteInfoBean() ~g%Ht#<  
{//nSplitter的缺省值为5 FhPCFmmUT  
//default value of nSplitter is 5 ,`OQAJ)>  
this("","","",5); S>p0{:zM  
} G;J)[y  
+Wgfxk'{  
_"OE}$C  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 717G CL@  
{ QN?EI: q=  
sSiteURL= sURL; FC~%G&K/q^  
sFilePath = sPath; \{!,a  
sFileName = sName; *-(o. !#1  
this.nSplitter = nSpiltter; !! )W`  
'x<oILOG  
-rjQ^ze  
} 9[W >`JKo  
Gg]Jp:GF  
[Y?Y@x"MZ  
public String getSSiteURL() ms!|a_H7r  
{ {]Cn@.TPD  
return sSiteURL; wf1p/bpf  
}  ^u#iz  
<3/_'/C  
Lz p}<B  
public void setSSiteURL(String value) M#-E  
{ C^5 V  
sSiteURL = value; lN8l71N^  
} >p0,]-.J,r  
bBXLW}W  
:<k (y?GB  
public String getSFilePath() ]NI CQ9  
{ tJn"$A^N  
return sFilePath; T9!NuKfur  
} A%7f;&x!  
C^;8M
'8z0  
1E'PSq  
public void setSFilePath(String value) =
au!rda  
{ fH?A.JP=a  
sFilePath = value; ?8?vBkz~  
} XGbpH<
 
-Ah&|!/  
VCiq'LOR,<  
public String getSFileName() QtXiUx^ k<  
{ /988K-5k  
return sFileName; YTmHht{j#  
} Y*p<\{,oC  
sLJ]N0t  
Iz j-,a  
public void setSFileName(String value) :dRC$?f4  
{ X%&7-P
O  
sFileName = value; u0,QsD)_X0  
} FE^/us7r  
?daxb  
IbL'Z   
public int getNSplitter() H_t0$x(\  
{ kaiK1/W0;  
return nSplitter; QRrAyRf[  
} m&DI2he  
x3#:C=  
0'.z|
Jg=  
public void setNSplitter(int nCount) s]0 J'UN  
{ gPc1oc(  
nSplitter = nCount; rPyjr(I"_  
} <uJ {>~  
} MMC$c=4"  
S9 $t9o  
FE{c{G<  
/* Tp{jR<  
**Utility.java WAR!#E#J7  
*/ )\VuN-d  
package NetFox; 67&Q<`V1*q  
aXQAm$/ >  
pc@mQI  
public class Utility { 2RF3pIFrm  
&a e!lB  
F.i}&UQ%  
public Utility() +Yq?:uBV  
{ pY3/AO=  
.d[^&<^  
dTCLE t.  
} T,uF^%$@AQ  
<t
a{)}IN^  
//线程睡眠 +v5f-CBu  
public static void sleep(int nSecond) skan1wQ  
{ RMpiwO^  
try{ KnA BFH  
Thread.sleep(nSecond);  4q7H  
} C;/ONF   
catch(Exception e) .|g@#XIwe#  
{ Mt`LOdiC_  
e.printStackTrace (); eN </H.bm]  
} "eOl(TSu/  
} ^E\n^D-RV  
}vOg9/[{  
//日志 N%Y!{k5T7  
public static void log(String sMsg) ohyq/u+y~A  
{ _Li.}g@Bd  
System.err.println(sMsg); He4HIZ  
} 0-{E% k  
wme#8/eUk  
MZf?48"f  
public static void log(int sMsg) 4gev^/^^  
{ w/*#TDR  
System.err.println(sMsg); }a,ycFt  
} cC/32SmY4  
} sq(5k+y*J  
rr\u)D#)  
fJ5mKN  
/* .57Fh)Y  
**TestMethod.java "q=ss:(  
*/ ?SO
!INJ  
package NetFox; zh=0zJ  
@6+_0^  
/U!B2%vq_  
public class TestMethod { +aM[!pW(e  
st)v'ce,  
a'Odw2Q_  
public TestMethod() :OjmaP
 
{ ///xx/weblogic60b2_win.exe NvTK7? v  
try{ 8rlf9m  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *q,nALs  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); RFFbS{
U*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5[B)U">]  
fileFetch.start(); b&4JHyleF  
} X 5}=|%Y  
catch(Exception e){e.printStackTrace ();} uqI'e_&=&5  
p<0=. ~  
-EFdP]XO  
} :eD-'#@$u  
/4+Q; P  
|@1(^GX  
public static void main(String[] args) 0g=vMLi  
{ 3WwCo.q;m  
new TestMethod(); UY({[?Se  
} LY)Wwl*wc  
} S *J{  
点击下载更多相关资料