Spring JdbcTemplate學習筆記

1、使用JdbcTemplate的execute()方法執行SQL語句

jdbcTemplate.execute("CREATE TABLE USER (user_id integer, name varchar(100))");

jdbcTemplate.update("INSERT INTO USER VALUES('"


       + user.getId() + "', '"
       + user.getName() + "', '"
       + user.getSex() + "', '"
       + user.getAge() + "')");</pre><br />

3、帶參數的更新

jdbcTemplate.update("UPDATE USER SET name = ? WHERE user_id = ?", new Object[] {name, id});


jdbcTemplate.update("INSERT INTO USER VALUES(?, ?, ?, ?)", new Object[] {user.getId(), user.getName(), user.getSex(), user.getAge()});


4、使用JdbcTemplate進行查詢時，使用queryForXXX()等方法

int count = jdbcTemplate.queryForInt("SELECT COUNT(*) FROM USER");




String name = (String) jdbcTemplate.queryForObject("SELECT name FROM USER WHERE user_id = ?", new Object[] {id}, java.lang.String.class);




List rows = jdbcTemplate.queryForList("SELECT * FROM USER");




List rows = jdbcTemplate.queryForList("SELECT * FROM USER");
Iterator it = rows.iterator();
while(it.hasNext()) {
    Map userMap = (Map) it.next();
    System.out.print(userMap.get("user_id") + "\t");
    System.out.print(userMap.get("name") + "\t");
    System.out.print(userMap.get("sex") + "\t");
    System.out.println(userMap.get("age") + "\t");
}




   JdbcTemplate將我們使用的JDBC的流程封裝起來，包括了異常的捕捉、SQL的執行、查詢結果的轉換等等。spring大量使用Template Method模式來封裝固定流程的動作，XXXTemplate等類別都是基于這種方式的實現。

    除了大量使用Template Method來封裝一些底層的操作細節，spring也大量使用callback方式類回調相關類別的方法以提供JDBC相關類別的功能，使傳統的JDBC的使用者也能清楚了解spring所提供的相關封裝類別方法的使用。



JDBC的PreparedStatement

final String id = user.getId();
final String name = user.getName();
final String sex = user.getSex() + "";
final int age = user.getAge();

jdbcTemplate.update("INSERT INTO USER VALUES(?, ?, ?, ?)",
                     new PreparedStatementSetter() {
                         public void setValues(PreparedStatement ps) throws SQLException {
                             ps.setString(1, id);
                             ps.setString(2, name);

                             ps.setString(3, sex);
                             ps.setInt(4, age);
                         }
                     });</pre>



final User user = new User();
jdbcTemplate.query("SELECT * FROM USER WHERE user_id = ?",
                    new Object[] {id},
                    new RowCallbackHandler() {
                        public void processRow(ResultSet rs) throws SQLException {
                            user.setId(rs.getString("user_id"));
                            user.setName(rs.getString("name"));
                            user.setSex(rs.getString("sex").charAt(0));
                            user.setAge(rs.getInt("age"));
                        }
                    });








class UserRowMapper implements RowMapper {
    public Object mapRow(ResultSet rs, int index) throws SQLException {
        User user = new User();


    user.setId(rs.getString("user_id"));
    user.setName(rs.getString("name"));
    user.setSex(rs.getString("sex").charAt(0));
    user.setAge(rs.getInt("age"));

    return user;
}

}
public List findAllByRowMapperResultReader() {
    String sql = "SELECT * FROM USER";
    return jdbcTemplate.query(sql, new RowMapperResultReader(new UserRowMapper()));
}</pre>



在getUser(id)里面使用UserRowMapper

public User getUser(final String id) throws DataAccessException {
    String sql = "SELECT * FROM USER WHERE user_id=?";
    final Object[] params = new Object[] { id };
    List list = jdbcTemplate.query(sql, params, new RowMapperResultReader(new UserRowMapper()));


return (User) list.get(0);

}</pre>



網上收集

org.springframework.jdbc.core.PreparedStatementCreator 返回預編譯SQL   不能于Object[]一起用

 public PreparedStatement createPreparedStatement(Connection con) throws SQLException {
  return con.prepareStatement(sql);
 }


1.增刪改

org.springframework.jdbc.core.JdbcTemplate   類(必須指定數據源dataSource)

 template.update("insert into web_person values(?,?,?)",Object[]);


  或

 template.update("insert into web_person values(?,?,?)",new PreparedStatementSetter(){ 匿名內部類 只能訪問外部最終局部變量

public void setValues(PreparedStatement ps) throws SQLException {
   ps.setInt(index++,3);
 });</pre>

org.springframework.jdbc.core.PreparedStatementSetter 接口 處理預編譯SQL

 public void setValues(PreparedStatement ps) throws SQLException {
  ps.setInt(index++,3);
 }


2.查詢JdbcTemplate.query(String,[Object[]/PreparedStatementSetter],RowMapper/RowCallbackHandler)

org.springframework.jdbc.core.RowMapper   記錄映射接口  處理結果集

 public Object mapRow(ResultSet rs, int arg1) throws SQLException {   int表當前行數
   person.setId(rs.getInt("id"));
 }
 List template.query("select * from web_person where id=?",Object[],RowMapper);


org.springframework.jdbc.core.RowCallbackHandler  記錄回調管理器接口 處理結果集

 template.query("select * from web_person where id=?",Object[],new RowCallbackHandler(){
  public void processRow(ResultSet rs) throws SQLException {
   person.setId(rs.getInt("id"));
 });