java关闭resultset,connection,preparedstatement出错


    public List<Product>  searchAll(){
        List<Product> ps = new ArrayList<Product>();
        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        
        try{
            String url = "jfdbc:mysql://localhost:3306/bookstoredb";
            conn = DriverManager.getConnection(url,"root","0609chenwanyi");
            
            String sql = "select * from bookstoredb.product";
            pstmt = conn.prepareStatement(sql);
            rs = pstmt.executeQuery();
            
                while (rs.next()) {
                Product p = new Product();
                p.setId(rs.getString(1));
                p.setName(rs.getString(2));
                p.setPrice(rs.getDouble(3));
                p.setCategory(rs.getString(4));
                p.setPnum(rs.getInt(5));
                p.setImgurl(rs.getString(6));
                p.setDescription(rs.getString(7));
                ps.add(p);
                }
        }catch(Exception e) {e.printStackTrace();}
        finally {
        }
        if (rs != null)
            rs.close();
        if (pstmt != null)
            pstmt.close();
        if (conn != null)
            conn.close();
        return ps;
    }

img

代码改动:

    try{
        String url = "jfdbc:mysql://localhost:3306/bookstoredb";
        conn = DriverManager.getConnection(url,"root","0609chenwanyi");
        
        String sql = "select * from bookstoredb.product";
        pstmt = conn.prepareStatement(sql);
        rs = pstmt.executeQuery();
        
            while (rs.next()) {
            Product p = new Product();
            p.setId(rs.getString(1));
            p.setName(rs.getString(2));
            p.setPrice(rs.getDouble(3));
            p.setCategory(rs.getString(4));
            p.setPnum(rs.getInt(5));
            p.setImgurl(rs.getString(6));
            p.setDescription(rs.getString(7));
            ps.add(p);
            }
    }catch(Exception e) {e.printStackTrace();}
    finally {
      try {
        if (rs != null)
        rs.close();
    if (pstmt != null)
        pstmt.close();
    if (conn != null)
        conn.close();
          } catch(Exception e) {
        e.printStackTrace();
      }
    }
    
    return ps;
}

需捕获异常,再有错误,贴出来。

把他们用try/catch块抱起来,这里是需要抛出或者捕获异常的