JdbcTemplate学习笔记

使用JdbcTemplate的execute()方法执行SQL语句
Java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

   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

   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

   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

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

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



Java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

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

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



Java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

   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

   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

   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

   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

   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

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

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


  或
Java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

   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

   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

   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. });