JDBC PreparedStatement操作

1 插入數據

public boolean ChaRu3(User user){
boolean flag=true;
        Connection conn=null;
        PreparedStatement ps=null;    //創建PreparedStatement 對象
        String sql= "insert into user (name,pwd) values(?,?)";  //sql語句不再採用拼接方式，應用佔位符問號的方式寫sql語句。
        conn=DBConnUtil.getConn();
try {
            ps=conn.prepareStatement(sql);
            ps.setString(1, user.getName()); //對佔位符設置值，佔位符順序從1開始，第一個參數是佔位符的位置，第二個參數是佔位符的值。
            ps.setString(2, user.getPwd()); 
int i=ps.executeUpdate();
if(i==0){
                flag=false;
            }
        } catch (SQLException e) {
// TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            DBConnUtil.closeAll(null, ps, conn);
        }
return flag;

    }

 

2 修改數據

 

public boolean XiuGai3(User user){
boolean flag=true;
        Connection conn=null;
        PreparedStatement ps=null;
        String sql="update user set pwd=? where name=?";
        conn=DBConnUtil.getConn();
try {
            ps=conn.prepareStatement(sql);
            ps.setString(1, user.getPwd());
            ps.setString(2, user.getName());
int i= ps.executeUpdate();
if(i==0){
                flag=false;
            }

        } catch (SQLException e) {
// TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            DBConnUtil.closeAll(null, ps, conn);
        }
return flag;
    }

 

3 刪除數據

public boolean ShanChu3(int id){
boolean flag=true;
        Connection conn=null;
        PreparedStatement ps=null;
        String sql="delete from user where id=?";
        conn=DBConnUtil.getConn();
try {
            ps=conn.prepareStatement(sql);
            ps.setInt(1, id);
int i=ps.executeUpdate();
if(i==0){
                flag=false;
            }
        } catch (SQLException e) {
// TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            DBConnUtil.closeAll(null, ps, conn);
        }

return flag;
    }

 

4 查看數據

public List<User> ChaKan3(){
         List<User> list= new ArrayList<User>();
         Connection conn=null;
         PreparedStatement ps=null;
         ResultSet rs=null;
         String sql="select * from user";
         conn=DBConnUtil.getConn();
try {
               ps=conn.prepareStatement(sql);
             rs=ps.executeQuery();
while(rs.next()){
                User user= new User();
                user.setName(rs.getString("name"));
                list.add(user);
             }
        } catch (SQLException e) {
// TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            DBConnUtil.closeAll(rs, ps, conn);
        }

return list;
     }