JdbcTemplate学习笔记

URL:http://www.iteye.com/topic/53526

1、使用JdbcTemplate的execute()方法执行SQL语句
Java代码 复制代码

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

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


2、如果是UPDATE或INSERT,可以用update()方法。
Java代码 复制代码

   1. jdbcTemplate.update("INSERT INTO USER VALUES('"  
   2.            + user.getId() + "', '"  
   3.            + user.getName() + "', '"  
   4.            + user.getSex() + "', '"  
   5.            + user.getAge() + "')");  

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


3、带参数的更新
Java代码 复制代码

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

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


Java代码 复制代码

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

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
Java代码 复制代码

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

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



Java代码 复制代码

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

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



Java代码 复制代码

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

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



Java代码 复制代码

   1. List rows = jdbcTemplate.queryForList("SELECT * FROM USER");  
   2. Iterator it = rows.iterator();  
   3. while(it.hasNext()) {  
   4.     Map userMap = (Map) it.next();  
   5.     System.out.print(userMap.get("user_id") + "\t");  
   6.     System.out.print(userMap.get("name") + "\t");  
   7.     System.out.print(userMap.get("sex") + "\t");  
   8.     System.out.println(userMap.get("age") + "\t");  
   9. }  

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
Java代码 复制代码

   1. final String id = user.getId();  
   2. final String name = user.getName();  
   3. final String sex = user.getSex() + "";  
   4. final int age = user.getAge();  
   5.   
   6. jdbcTemplate.update("INSERT INTO USER VALUES(?, ?, ?, ?)",  
   7.                      new PreparedStatementSetter() {  
   8.                          public void setValues(PreparedStatement ps) throws SQLException {  
   9.                              ps.setString(1, id);  
  10.                              ps.setString(2, name);            
  11.                              ps.setString(3, sex);  
  12.                              ps.setInt(4, age);  
  13.                          }  
  14.                      });  

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);
                         }
                     });




Java代码 复制代码

   1. final User user = new User();  
   2. jdbcTemplate.query("SELECT * FROM USER WHERE user_id = ?",  
   3.                     new Object[] {id},  
   4.                     new RowCallbackHandler() {  
   5.                         public void processRow(ResultSet rs) throws SQLException {  
   6.                             user.setId(rs.getString("user_id"));  
   7.                             user.setName(rs.getString("name"));  
   8.                             user.setSex(rs.getString("sex").charAt(0));  
   9.                             user.setAge(rs.getInt("age"));  
  10.                         }  
  11.                     });  

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"));
                        }
                    });






Java代码 复制代码

   1. class UserRowMapper implements RowMapper {  
   2.     public Object mapRow(ResultSet rs, int index) throws SQLException {  
   3.         User user = new User();  
   4.   
   5.         user.setId(rs.getString("user_id"));  
   6.         user.setName(rs.getString("name"));  
   7.         user.setSex(rs.getString("sex").charAt(0));  
   8.         user.setAge(rs.getInt("age"));  
   9.   
  10.         return user;  
  11.     }  
  12. }  
  13.   
  14. public List findAllByRowMapperResultReader() {  
  15.     String sql = "SELECT * FROM USER";  
  16.     return jdbcTemplate.query(sql, new RowMapperResultReader(new UserRowMapper()));  
  17. }  

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
Java代码 复制代码

   1. public User getUser(final String id) throws DataAccessException {  
   2.     String sql = "SELECT * FROM USER WHERE user_id=?";  
   3.     final Object[] params = new Object[] { id };  
   4.     List list = jdbcTemplate.query(sql, params, new RowMapperResultReader(new UserRowMapper()));  
   5.   
   6.     return (User) list.get(0);  
   7. }  

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
Java代码 复制代码

   1. public PreparedStatement createPreparedStatement(Connection con) throws SQLException {  
   2.  return con.prepareStatement(sql);  
   3. }  

 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)
Java代码 复制代码

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

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


或
Java代码 复制代码

   1. 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  
   2.   
   3.  public void setValues(PreparedStatement ps) throws SQLException {  
   4.   ps.setInt(index++,3);  
   5. });  

 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
Java代码 复制代码

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

 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
Java代码 复制代码

   1. public Object mapRow(ResultSet rs, int arg1) throws SQLException {   int表当前行数  
   2.   person.setId(rs.getInt("id"));  
   3. }  
   4. List template.query("select * from web_person where id=?",Object[],RowMapper);  

 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
Java代码 复制代码

   1. template.query("select * from web_person where id=?",Object[],new RowCallbackHandler(){  
   2.  public void processRow(ResultSet rs) throws SQLException {  
   3.   person.setId(rs.getInt("id"));  
   4. });