怎样在一个文件中查找一个字符串？

Question

Stringint indexOf(String str) 
          Returns the index within this string of the first occurrence of the specified substring. 

Answer 1

String filename = new String();
FileInputStream in = null;
in = new FileInputStream(path+"/"+name);
int num = in.available();
byte[] buffer = new byte[num];
in.read(buffer);
in.close();
dessert = new String(buffer,0);
int bein = 0;
bein = dessert.indexOf("所要查询的字串");
/*所以bein就是字符串所在的位置,如果是-1，就说明不包含该字串*/

Answer 2

public static void Find() throws Exception {
  
           BufferedReader bj=new BufferedReader(new InputStreamReader(System.in));                System.out.print("\nPlease input the name of file:>");                String FileName=bj.readLine().trim();                BufferedReader in=new BufferedReader(new FileReader(FileName));
                
                System.out.print("\nPlease input the String you want to locate:>");
                
                //enter the string that the users want to find;
                String FindLine=bj.readLine();
                
         String Line;
        
         int flat=0, SumLine=0;
        
         //read each line in file;
         Line=in.readLine();
        
           //if this file is empty,then display some information; then go to next loop; menu choice
           if (Line==null) {
        
         System.out.print("\nSorry,The string you want to find doesn't exist!"); 
        
        
           }
           
           else {
           
           //if Line isn't equal to null ,add one to SumLine;
           SumLine++;
        
           //find the column location of string;
           flat=Line.indexOf(FindLine);
           
           
             
             while(true){
           
             //if find string in current line, then display some information;then go out of while loop
             if (flat!=-1) {
                        
                       System.out.print("\nThe string you want to find is located in "+SumLine+ " Line, "
                           
                                        +(flat+1)+" Column.");
        
                break;
                             
                       } 
                          
                     //if do not find string in current line,the program will continuously go to next line,
                     //and if "Line"=null, we can conclude the process has already arrived the last Line. 
                     else  {
                              
                            Line=in.readLine(); 
                                                                   
             if (Line==null) {
        
                System.out.print("\nSorry,The string you want to find doesn't exist!"); 
                             
                               //can't find. so quit the loop to go to the first menu loop;
                               break;
                            
                               } 
                             
                            //if do not find string. pass the each Line ,the SumLine will be added itself;
                            SumLine++;
        
             //find the column location of string repeatly;
                            flat=Line.indexOf(FindLine);
                          
                          }
               
                  }
        
          }        
        
     }