FastJSON是一个很好的java开源json工具类库，相比其他同类的json类库，它的速度的确是快，所以在开发中我们会使用到fastjson，那fastjson如何使用?下面来我们就来给大家讲解一下fastjson使用详解。
FastJson基本使用
将POJO对象转换成Json格式String
JSON.toJSONString(Object)
将Json格式字符串转换成POJO对象
JSON.parseObject(jsonStr, pojoCls)
实例
private static class UserGroup
{
private int groupId;
private String name;
public int getGroupId()
{
return groupId;
}
public void setGroupId(int groupId)
{
this.groupId = groupId;
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
}UserGroup userGroup = new UserGroup();
userGroup.setGroupId(1);
userGroup.setName("group1");
//encode
String jsonValue = JSON.toJSONString(userGroup);
//decode
UserGroup group = JSON.parseObject(jsonValue, UserGroup.class);FastJson自定义序列化与反序列化
1.自定义序列化
a.实现ObjectSerializer
public class OrderActionEnumSerializer implements ObjectSerializer
{
@Override
public void write(JSONSerializer serializer, Object object, Object fieldName, Type fieldType, int features) throws IOException
{
SerializeWriter writer = serializer.out;
OrderActionEnum orderActionEnum = (OrderActionEnum) object;
writer.write(orderActionEnum.getValue());
}
}b.注册序列化接口
SerializeConfig.getGlobalInstance() .put(OrderActionEnum.class, new OrderActionEnumSerializer());
2.自定义反序列化
a. 实现反序列化接口
public class OrderActionEnumDeserializer implements ObjectDeserializer
{
@Override
public < T > T deserialze(DefaultJSONParser parser, Type type, Object fieldName)
{
Integer intValue = parser.parseObject(int.class);
OrderActionEnum orderActionEnum = OrderActionEnum.getOrderAction(intValue);
if (orderActionEnum != null)
{
return (T) orderActionEnum;
}
throw new IllegalStateException();
}
@Override
public int getFastMatchToken()
{
return JSONToken.LITERAL_INT;
}
}b.注册反序列化
ParserConfig.getGlobalInstance() .putDeserializer(OrderActionEnum.class, new OrderActionEnumDeserializer());
3.序列化和反序列化测试
public void test()
{
Msg msg = new Msg();
msg.setBody("hello world");
msg.setActionEnum(OrderActionEnum.SUC);
String jsonValue = JSON.toJSONString(msg);
System.out.println(jsonValue);
Msg msg2 = JSON.parseObject(jsonValue, Msg.class);
Assert.assertTrue(msg2.getBody()
.equals(msg.getBody()));
Assert.assertTrue(msg2.getActionEnum()
.equals(msg.getActionEnum()));
System.out.println(msg2);
}public enum OrderActionEnum
{
FAIL(1, "FAIL")
, SUC(0, "SUC"), ;
private int value;
private OrderActionEnum(int value, String desc)
{
this.value = value;
}
public int getValue()
{
return value;
}
public static OrderActionEnum getOrderAction(int value)
{
for (OrderActionEnum valueEnm: values())
{
if (value == valueEnm.getValue())
{
return valueEnm;
}
}
return null;
}
}public class Msg
{
private OrderActionEnum actionEnum;
private String body;
public OrderActionEnum getActionEnum()
{
return actionEnum;
}
public void setActionEnum(OrderActionEnum actionEnum)
{
this.actionEnum = actionEnum;
}
public String getBody()
{
return body;
}
public void setBody(String body)
{
this.body = body;
}
}总之FastJson是阿里巴巴的开源JSON解析库，它可以解析JSON格式的字符串，支持将Java Bean序列化为JSON字符串，也可以从JSON字符串反序列化到JavaBean，并且虽然FastJson有漏洞，但是也是开发中重要解析库哦!最后大家如果想要了解更多json相关知识，敬请关注奇Q工具网。
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