如何将Java对象转换成JSON

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.47</version>         
</dependency>

package Bean;
public class User 
{
	private Integer id;
	private String name;
	private String pass;
	private String sex;
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPass() {
		return pass;
	}
	public void setPass(String pass) {
		this.pass = pass;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
}

package WebTest;
import Bean.User;
import com.alibaba.fastjson.JSON;
public class JsonTest 
{
	public static void main(String[] args) 
	{
		User user= new User();
		user.setId(1);
		user.setName("lzc");
		user.setPass("123");
		user.setSex("male");
		String json=JSON.toJSONString(user);//关键
		System.out.println(json);
	}
}