jdbcTemplate学习笔记(转)

1、使用JdbcTemplate的execute()方法执行SQL语句

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

2、如果是UPDATE或INSERT,可以用update()方法

jdbcTemplate.update("INSERT INTO USER VALUES('"  
          + user.getId() + "', '"  
          + user.getName() + "', '"  
          + user.getSex() + "', '"  
          + user.getAge() + "')");  

3、带参数的更新

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进行查询时，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将我们使用的JDBC的流程封装起来，包括了异常的捕捉、SQL的执行、查询结果的转换等等。spring大量使用Template Method模式来封装固定流程的动作，XXXTemplate等类别都是基于这种方式的实现。
    除了大量使用Template Method来封装一些底层的操作细节，spring也大量使用callback方式类回调相关类别的方法以提供JDBC相关类别的功能，使传统的JDBC的使用者也能清楚了解spring所提供的相关封装类别方法的使用。

 

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);   
	                          }   
	                      });  

 

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()));   
		 }

 

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);   
		 }

网上收集
org.springframework.jdbc.core.PreparedStatementCreator 返回预编译SQL   不能于Object[]一起用

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

1.增删改

org.springframework.jdbc.core.JdbcTemplate   类(必须指定数据源dataSource)

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

 

template.update("insert into web_person values(?,?,?)",new PreparedStatementSetter(){ 匿名内部类 只能访问外部最终局部变量   
		 
		  public void setValues(PreparedStatement ps) throws SQLException {   
		  ps.setInt(index++,3);   
		 });

org.springframework.jdbc.core.PreparedStatementSetter 接口 处理预编译SQL

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

2.查询JdbcTemplate.query(String,[Object[]/PreparedStatementSetter],RowMapper/RowCallbackHandler)
org.springframework.jdbc.core.RowMapper   记录映射接口  处理结果集

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

org.springframework.jdbc.core.RowCallbackHandler  记录回调管理器接口 处理结果集

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