使用Jackson来实现Java对象与JSON的相互转换的教程

 import java.io.IOException; import java.text.ParseException; import java.text.SimpleDateFormat; import com.fasterxml.jackson.databind.ObjectMapper; public class JacksonDemo { public static void main(String[] args) throws ParseException, IOException { User user = new User(); user.setName("小民"); user.setEmail("xiaomin@sina.com"); user.setAge(20); SimpleDateFormat dateformat = new SimpleDateFormat("yyyy-MM-dd"); user.setBirthday(dateformat.parse("1996-10-01")); /** * ObjectMapper是JSON操作的核心，Jackson的所有JSON操作都是在ObjectMapper中实现。 * ObjectMapper有多个JSON序列化的方法，可以把JSON字符串保存File、OutputStream等不同的介质中。 * writeValue(File arg0, Object arg1)把arg1转成json序列，并保存到arg0文件中。 * writeValue(OutputStream arg0, Object arg1)把arg1转成json序列，并保存到arg0输出流中。 * writeValueAsBytes(Object arg0)把arg0转成json序列，并把结果输出成字节数组。 * writeValueAsString(Object arg0)把arg0转成json序列，并把结果输出成字符串。 */ ObjectMapper mapper = new ObjectMapper(); //User类转JSON //输出结果：{"name":"小民","age":20,"birthday":844099200000,"email":"xiaomin@sina.com"} String json = mapper.writeValueAsString(user); System.out.println(json); //Java集合转JSON //输出结果：[{"name":"小民","age":20,"birthday":844099200000,"email":"xiaomin@sina.com"}] List users = new ArrayList(); users.add(user); String jsonlist = mapper.writeValueAsString(users); System.out.println(jsonlist); } } 

 import java.io.IOException; import java.text.ParseException; import com.fasterxml.jackson.databind.ObjectMapper; public class JacksonDemo { public static void main(String[] args) throws ParseException, IOException { String json = "{\"name\":\"小民\",\"age\":20,\"birthday\":844099200000,\"email\":\"xiaomin@sina.com\"}"; /** * ObjectMapper支持从byte[]、File、InputStream、字符串等数据的JSON反序列化。 */ ObjectMapper mapper = new ObjectMapper(); User user = mapper.readValue(json, User.class); System.out.println(user); } } 

 private static final String MODEL_BINDING = "{\"name\":\"name1\",\"type\":1}"; public void fullDataBinding() throws Exception{ ObjectMapper mapper = new ObjectMapper(); Model user = mapper.readValue(MODEL_BINDING, Model.class);//readValue到一个实体类中. System.out.println(user.getName()); System.out.println(user.getType()); } 

 private static class Model{ private String name; private int type; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getType() { return type; } public void setType(int type) { this.type = type; } } 

 /** Concrete Java types that Jackson will use for simple data binding are: JSON Type    Java Type object     LinkedHashMap array      ArrayList